earth objects neo: Topics by Science.gov

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Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies

NASA Technical Reports Server (NTRS)

2010-01-01

The United States spends approximately four million dollars each year searching for near-Earth objects (NEOs). The objective is to detect those that may collide with Earth. The majority of this funding supports the operation of several observatories that scan the sky searching for NEOs. This, however, is insufficient in detecting the majority of NEOs that may present a tangible threat to humanity. A significantly smaller amount of funding supports ways to protect the Earth from such a potential collision or "mitigation." In 2005, a Congressional mandate called for NASA to detect 90 percent of NEOs with diameters of 140 meters of greater by 2020. Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies identifies the need for detection of objects as small as 30 to 50 meters as these can be highly destructive. The book explores four main types of mitigation including civil defense, "slow push" or "pull" methods, kinetic impactors and nuclear explosions. It also asserts that responding effectively to hazards posed by NEOs requires national and international cooperation. Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies is a useful guide for scientists, astronomers, policy makers and engineers.
Accessible Near-Earth Objects (NEOs)

NASA Technical Reports Server (NTRS)

Barbee, Brent W.

2015-01-01

Near Earth Objects (NEOs) are asteroids and comets whose orbits are in close proximity to Earth's orbit; specifically, they have perihelia less than 1.3 astronomical units. NEOs particularly near Earth asteroids (NEAs) are identified as potential destinations for future human exploration missions. In this presentation I provide an overview of the current state of knowledge regarding the astrodynamical accessibility of NEAs according to NASA's Near Earth Object Human Space Flight Accessible Targets Study (NHATS). I also investigate the extremes of NEA accessibility using case studies and illuminate the fact that a space-based survey for NEOs is essential to expanding the set of known accessible NEAs for future human exploration missions.
Near-Earth object hazardous impact: A Multi-Criteria Decision Making approach.

PubMed

Sánchez-Lozano, J M; Fernández-Martínez, M

2016-11-16

The impact of a near-Earth object (NEO) may release large amounts of energy and cause serious damage. Several NEO hazard studies conducted over the past few years provide forecasts, impact probabilities and assessment ratings, such as the Torino and Palermo scales. These high-risk NEO assessments involve several criteria, including impact energy, mass, and absolute magnitude. The main objective of this paper is to provide the first Multi-Criteria Decision Making (MCDM) approach to classify hazardous NEOs. Our approach applies a combination of two methods from a widely utilized decision making theory. Specifically, the Analytic Hierarchy Process (AHP) methodology is employed to determine the criteria weights, which influence the decision making, and the Technique for Order Performance by Similarity to Ideal Solution (TOPSIS) is used to obtain a ranking of alternatives (potentially hazardous NEOs). In addition, NEO datasets provided by the NASA Near-Earth Object Program are utilized. This approach allows the classification of NEOs by descending order of their TOPSIS ratio, a single quantity that contains all of the relevant information for each object.
The Near Earth Object (NEO) Scout Spacecraft: A Low-cost Approach to In-situ Characterization of the NEO Population

NASA Technical Reports Server (NTRS)

Woeppel, Eric A.; Balsamo, James M.; Fischer, Karl J.; East, Matthew J.; Styborski, Jeremy A.; Roche, Christopher A.; Ott, Mackenzie D.; Scorza, Matthew J.; Doherty, Christopher D.; Trovato, Andrew J.;

2014-01-01

This paper describes a microsatellite spacecraft with supporting mission profile and architecture, designed to enable preliminary in-situ characterization of a significant number of Near Earth Objects (NEOs) at reasonably low cost. The spacecraft will be referred to as the NEO-Scout. NEO-Scout spacecraft are to be placed in Geosynchronous Equatorial Orbit (GEO), cis-lunar space, or on earth escape trajectories as secondary payloads on launch vehicles headed for GEO or beyond, and will begin their mission after deployment from the launcher. A distinguishing key feature of the NEO-Scout system is to design the spacecraft and mission timeline so as to enable rendezvous with and landing on the target NEO during NEO close approach (<0.3 AU) to the Earth-Moon system using low-thrust/high-impulse propulsion systems. Mission durations are on the order 100 to 400 days. Mission feasibility and preliminary design analysis are presented, along with detailed trajectory calculations.

An High Resolution Near-Earth Objects Population Enabling Next-Generation Search Strategies

NASA Technical Reports Server (NTRS)

Tricaico, Pasquale; Beshore, E. C.; Larson, S. M.; Boattini, A.; Williams, G. V.

2010-01-01

Over the past decade, the dedicated search for kilometer-size near-Earth objects (NEOs), potentially hazardous objects (PHOs), and potential Earth impactors has led to a boost in the rate of discoveries of these objects. The catalog of known NEOs is the fundamental ingredient used to develop a model for the NEOs population, either by assessing and correcting for the observational bias (Jedicke et al., 2002), or by evaluating the migration rates from the NEOs source regions (Bottke et al., 2002). The modeled NEOs population is a necessary tool used to track the progress in the search of large NEOs (Jedicke et al., 2003) and to try to predict the distribution of the ones still undiscovered, as well as to study the sky distribution of potential Earth impactors (Chesley & Spahr, 2004). We present a method to model the NEOs population in all six orbital elements, on a finely grained grid, allowing us the design and test of targeted and optimized search strategies. This method relies on the observational data routinely reported to the Minor Planet Center (MPC) by the Catalina Sky Survey (CSS) and by other active NEO surveys over the past decade, to determine on a nightly basis the efficiency in detecting moving objects as a function of observable quantities including apparent magnitude, rate of motion, airmass, and galactic latitude. The cumulative detection probability is then be computed for objects within a small range in orbital elements and absolute magnitude, and the comparison with the number of know NEOs within the same range allows us to model the population. When propagated to the present epoch and projected on the sky plane, this provides the distribution of the missing large NEOs, PHOs, and potential impactors.
The Mission Accessible Near-Earth Objects Survey (MANOS): First Photometric Results

NASA Astrophysics Data System (ADS)

Thirouin, A.; Moskovitz, N.; Binzel, R. P.; Christensen, E.; DeMeo, F. E.; Person, M. J.; Polishook, D.; Thomas, C. A.; Trilling, D.; Willman, M.; Hinkle, M.; Burt, B.; Avner, D.; Aceituno, F. J.

2016-12-01

The Mission Accessible Near-Earth Objects Survey aims to physically characterize sub-km near-Earth objects (NEOs). We report the first photometric results from the survey that began in 2013 August. Photometric observations were performed using 1-4 m class telescopes around the world. We present rotational periods and light curve amplitudes for 86 sub-km NEOs, though in some cases only lower limits are provided. Our main goal is to obtain light curves for small NEOs (typically, sub-km objects) and estimate their rotational periods, light curve amplitudes, and shapes. These properties are used for a statistical study to constrain overall properties of the NEO population. A weak correlation seems to indicate that smaller objects are more spherical than larger ones. We also report seven NEOs that are fully characterized (light curve and visible spectra) as the most suitable candidates for a future human or robotic mission. Viable mission targets are objects fully characterized, with Δv NHATS ≤ 12 km s-1, and a rotational period P > 1 hr. Assuming a similar rate of object characterization as reported in this paper, approximately 1230 NEOs need to be characterized in order to find 100 viable mission targets.
Physical modeling and high-performance GPU computing for characterization, interception, and disruption of hazardous near-Earth objects

NASA Astrophysics Data System (ADS)

Kaplinger, Brian Douglas

For the past few decades, both the scientific community and the general public have been becoming more aware that the Earth lives in a shooting gallery of small objects. We classify all of these asteroids and comets, known or unknown, that cross Earth's orbit as near-Earth objects (NEOs). A look at our geologic history tells us that NEOs have collided with Earth in the past, and we expect that they will continue to do so. With thousands of known NEOs crossing the orbit of Earth, there has been significant scientific interest in developing the capability to deflect an NEO from an impacting trajectory. This thesis applies the ideas of Smoothed Particle Hydrodynamics (SPH) theory to the NEO disruption problem. A simulation package was designed that allows efficacy simulation to be integrated into the mission planning and design process. This is done by applying ideas in high-performance computing (HPC) on the computer graphics processing unit (GPU). Rather than prove a concept through large standalone simulations on a supercomputer, a highly parallel structure allows for flexible, target dependent questions to be resolved. Built around nonclassified data and analysis, this computer package will allow academic institutions to better tackle the issue of NEO mitigation effectiveness.
Goals for Near-Earth-Object Exploration Examined

NASA Astrophysics Data System (ADS)

Showstack, Randy

2010-09-01

With Japan's Hayabusa space probe having returned a sample of the Itokawa asteroid this past June, and with NASA's Deep Impact spacecraft impactor having successfully struck comet Tempel 1 in 2006, among other recent missions, the study of near-Earth objects (NEOs) recently has taken some major steps forward. The recent discovery of two asteroids that passed within the Moon's distance of Earth on 8 September is a reminder of the need to further understand NEOs. During NASA's Exploration of Near-Earth Objects (NEO) Objectives Workshop, held in August in Washington, D. C., scientists examined rationales and goals for studying NEOs. Several recent documents have recognized NEO research as important as a scientific precursor for a potential mission to Mars, to learn more about the origins of the solar system, for planetary defense, and for resource exploitation. The October 2009 Review of Human Space Flight Plans Committee report (known as the Augustine report), for example, recommended a “flexible path ” for human exploration, with people visiting sites in the solar system, including NEOs. The White House's National Space Policy, released in June, indicates that by 2025, there should be “crewed missions beyond the moon, including sending humans to an asteroid.” In addition, NASA's proposed budget for fiscal year 2011 calls for the agency to send robotic precursor missions to nearby asteroids and elsewhere and to increase funding for identifying and cataloging NEOs.
The Near-Earth Object Camera

NASA Astrophysics Data System (ADS)

Mainzer, Amy K.; NEOCam Science Team

2017-10-01

The Near-Earth Object Camera (NEOCam) is a NASA mission in formulation designed to find, track, and provide basic physical characterization of asteroids and comets that make close approaches to Earth. Its goal is to reduce the risk of impacts from undetected near-Earth objects (NEOs) capable of causing global and regional disasters. NEOCam consists of a 50 cm telescope operating at two channels dominated by NEO thermal emission, 4.2-5.0um and 6-10um, in order to better constrain the objects' temperatures and diameters. Orbiting the Sun-Earth L1 Lagrange point, the mission would find hundreds of thousands of NEOs and would make significant progress toward the Congressional objective of discovering more than 90% of NEOs larger than 140 m during its five-year lifetime. The mission uses novel 2048x2048 HgCdTe detectors that extend the wavelength cutoff beyond 10um at an operating temperature of 40K (Dorn et al. 2016). Both the optical system and the detectors are cooled passively using radiators and thermal shields to enable long mission life and to avoid the complexity of cryocoolers or cryogens. NEOCam is currently in an extended Phase A.
Nasa s near earth object program office

NASA Astrophysics Data System (ADS)

Yeomans, D.; Chamberlin, A.; Chesley, S.; Chodas, P.; Giorgini, J.; Keesey, M.

In 1998, NASA formed the Near-Earth Object Program Office at JPL to provide a focal point for NASA's efforts to discover and monitor the motions of asteroids and comets that can approach the Earth. This office was charged with 1.) facilitating communication between the near-Earth object (NEO) community and the public, 2.) helping coordinate the search efforts for NEOs, 3.) monitoring the progress in finding NEOs at NASA -supported sites, and 4.) monitoring the future motions of all known NEOs and cataloging their orbits. There are far more near-Earth asteroids (NEAs) than near-Earth comets and one of the driving motivations for NASA's NEO Program is the Spaceguard Goal to find 90% of the NEAs larger than one kilometer by 2008. While the total population of NEAs is not clearly established, the consensus opinion seems to be that the total population of NEAs larger than one kilometer is about 1000 (with a range of perhaps 800 - 1200). By April 2002, nearly 60% of the total population of large NEAs had been discovered and while the discovery rate will likely drop off as the easy ones are found, these early discovery efforts are encouraging. The five NASA-supported NEO discovery teams are the Lincoln Laboratory Near-Earth Asteroid Research effort (LINEAR, Grant Stokes, Principal Investigator), the Near-Earth Asteroid Tracking team at JPL (NEAT, Eleanor Helin, P.I.), the Lowell Observatory Near-Earth Object Search (LONEOS, E. Bowell, P.I.), and two discovery teams near Tucson Arizona - the Spacewatch effort (R. McMillan, P.I.) and the Catalina Sky Survey group (S. Larson, P.I.). Mention should also be made of the Japanese Spaceguard discovery site at Bisei Japan (S. Isobe, P.I.). A substantial portion of the critical follow-up observations necessary to secure the orbits of NEOs and provide information on their physical characteristics is provided by a group of very sophisticated amateur astronomers who might better be described as unfunded professionals. After nearly two years in development, the JPL SENTRY system has been brought on line to provide automatic updates of near-Earth asteroid (NEA) orbits and to predict future close Earth approaches along with their associated impact probabilities. For those NEAs that can approach the Earth, a Palermo Scale risk number is computed based upon the object's impact probability at a particular time, the energy upon impact and the time interval before the potential impact. A Palermo Scale number larger than zero implies the predicted impact event has risen above the expected background level of impacts that could occur between now and the predicted time of impact from all NEAs of the same size or larger. Computed Palermo Scale values are used to prioritize automatic Monte Carlo numerical integration runs to determine robust impact probabilities for those NEAs where a future impact cannot be ruled out - usually because of poor orbits and/or close planetary encounters. Our interactive web site at http://neo.jpl.nasa.gov will allow the user access to the latest information on NEOs including coming close Earth approaches, the risk page for poorly determined orbits, the progress toward meeting the Spaceguard Goal, links to the web sites of the NEO search teams, the rationale for studying NEOs, space missions to NEOs, as well as information on the characteristics, future motions, orbits and orbital movies for well over 120,000 comets and asteroids.
The Mission Accessible Near-Earth Objects Survey (MANOS): spectroscopy results

NASA Astrophysics Data System (ADS)

Thomas, Cristina A.; Moskovitz, Nicholas; Hinkle, Mary L.; Mommert, Michael; Polishook, David; Thirouin, Audrey; Binzel, Richard; Christensen, Eric J.; DeMeo, Francesca E.; Person, Michael J.; Trilling, David E.; Willman, Mark; Burt, Brian

2016-10-01

The Mission Accessible Near-Earth Object Survey (MANOS) is an ongoing physical characterization survey to build a large, uniform catalog of physical properties including lightcurves and visible wavelength spectroscopy. We will use this catalog to investigate the global properties of the small NEO population and identify individual objects that can be targets of interest for future exploration. To accomplish our goals, MANOS uses a wide variety of telescopes (1-8m) in both the northern and southern hemispheres. We focus on targets that have been recently discovered and operate on a regular cadence of remote and queue observations to enable rapid characterization of small NEOs. Targets for MANOS are selected based on three criteria: mission accessibility, size, and observability. With our resources, we observe 5-10 newly discovered sub-km NEOs per month. MANOS has been operating for three years and we have observed over 500 near-Earth objects in that time.We will present results from the spectroscopy component of the MANOS program. Visible wavelength spectra are obtained using DeVeny on the Discovery Channel Telescope (DCT), Goodman on the Southern Astrophysical Research (SOAR) telescope, and GMOS on Gemini North and South. Over 300 NEO spectra have been obtained during our program. We will present preliminary results from our spectral sample. We will discuss the compositional diversity of the small NEO population and how the observed NEOs compare to the meteorite population.MANOS is funded by the NASA Near-Earth Object Observations program.
The orbital distribution of Near-Earth Objects inside Earth's orbit

NASA Astrophysics Data System (ADS)

Greenstreet, Sarah; Ngo, Henry; Gladman, Brett

2012-01-01

Canada's Near-Earth Object Surveillance Satellite (NEOSSat), set to launch in early 2012, will search for and track Near-Earth Objects (NEOs), tuning its search to best detect objects with a < 1.0 AU. In order to construct an optimal pointing strategy for NEOSSat, we needed more detailed information in the a < 1.0 AU region than the best current model (Bottke, W.F., Morbidelli, A., Jedicke, R., Petit, J.M., Levison, H.F., Michel, P., Metcalfe, T.S. [2002]. Icarus 156, 399-433) provides. We present here the NEOSSat-1.0 NEO orbital distribution model with larger statistics that permit finer resolution and less uncertainty, especially in the a < 1.0 AU region. We find that Amors = 30.1 ± 0.8%, Apollos = 63.3 ± 0.4%, Atens = 5.0 ± 0.3%, Atiras (0.718 < Q < 0.983 AU) = 1.38 ± 0.04%, and Vatiras (0.307 < Q < 0.718 AU) = 0.22 ± 0.03% of the steady-state NEO population. Vatiras are a previously undiscussed NEO population clearly defined in our integrations, whose orbits lie completely interior to that of Venus. Our integrations also uncovered the unexpected production of retrograde orbits from main-belt asteroid sources; this retrograde NEA population makes up ≃0.1% of the steady-state NEO population. The relative NEO impact rate onto Mercury, Venus, and Earth, as well as the normalized distribution of impact speeds, was calculated from the NEOSSat-1.0 orbital model under the assumption of a steady-state. The new model predicts a slightly higher Mercury impact flux.
The Exploration of Near-Earth Objects

NASA Astrophysics Data System (ADS)

1998-01-01

Near-Earth objects (NEOs) are asteroids and comets with orbits that intersect or pass near that of our planet. About 400 NEOs are currently known, but the entire population contains perhaps 3000 objects with diameters larger than 1 km. These objects, thought to be similar in many ways to the ancient planetesimal swarms that accreted to form the planets, are interesting and highly accessible targets for scientific research. They carry records of the solar system's birth and the geologic evolution of small bodies in the interplanetary region. Because collisions of NEOs with Earth pose a finite hazard to life, the exploration of these objects is particularly urgent. Devising appropriate risk-avoidance strategies requires quantitative characterization of NEOS. They may also serve as resources for use by future human exploration missions. The scientific goals of a focused NEO exploration program are to determine their orbital distribution, physical characteristics, composition, and origin. Physical characteristics, such as size, shape, and spin properties, have been measured for approximately 80 NEOs using observations at infrared, radar, and visible wavelengths. Mineralogical compositions of a comparable number of NEOs have been inferred from visible and near-infrared spectroscopy. The formation and geologic histories of NEOs and related main-belt asteroids are currently inferred from studies of meteorites and from Galileo and Near-Earth Asteroid Rendezvous spacecraft flybys of three main-belt asteroids. Some progress has also been made in associating specific types of meteorites with main-belt asteroids, which probably are the parent bodies of most NEOs. The levels of discovery of NEOs in the future will certainly increase because of the application of new detection systems. The rate of discovery may increase by an order of magnitude, allowing the majority of Earth-crossing asteroids and comets with diameters greater than 1 km to he discovered in the next decade. A small fraction of NEOs are particularly accessible for exploration by spacecraft. To identify the exploration targets of highest scientific interest, the orbits and classification of a large number of NEOs should be determined by telescopic observations. Desired characterization would also include measurements of size, mass, shape, surface composition and heterogeneity, gas and dust emission, and rotation. Laboratory studies of meteorites can focus NEO exploration objectives and quantify the information obtained from telescopes. Once high-priority targets have been identified, various kinds of spacecraft missions (flyby, rendezvous, and sample return) can be designed. Some currently operational (Near-Earth Asteroid Rendezvous [NEAR]) or planned (Deep Space 1) U.S. missions are of the first two types, and other planned U.S. and Japanese spacecraft missions will return samples. Rendezvous missions with sample return are particularly desirable from a scientific perspective because of the very great differences in the analytical capabilities that can be brought to bear in orbit and in the laboratory setting. Although it would be difficult to justify human exploration of NEOs on the basis of cost-benefit analysis of scientific results alone, a strong case can be made for starting with NEOs if the decision to carry out human exploration beyond low Earth orbit is made for other reasons. Some NEOs are especially attractive targets for astronaut missions because of their orbital accessibility and short flight duration. Because they represent deep space exploration at an intermediate level of technical challenge, these missions would also serve as stepping stones for human missions to Mars. Human exploration of NEOs would provide significant advances in observational and sampling capabilities. With respect to ground based telescopic studies, the recommended baseline is that NASA and other appropriate agencies suupport research programs for interpreting the spectra of near-Earth objects (NEOs), continue and coordinate currently supported surveys to discover and determine the orbits of NEOs and develop policies for the public disclosure of results relating to potential hazards. Augmentation to this baseline program include in priority order: (1) provide routine or priority access to existiing ground-based optical and infrared telescopes and radar facilities for characterization of NEOs during favorable encounters; or (2) provide expanded, dedicated telescope access for characterization of NEOs. Appropriate augmentations to existing programs include the following: (1) Develop technological advances in spacecraft capabilities, including nonchemical propulsion and autonomous navigation systems, low-power and low-mass anlaytical instrumentation for remote and in situ studies, and multiple penetrators and other sampling and sample-handling systems to allow low-cost rendezvous and sample return missions; and (2) study technical requirements for human expeditions to NEOs. Although studies evaluating the risk of asteroid collisions with Earth and the means of averting them are desirable, they are beyond the scope of this report.
Near-Earth Objects: Targets for Future Human Exploration, Solar System Science, and Planetary Defense

NASA Technical Reports Server (NTRS)

Abell, Paul A.

2011-01-01

Human exploration of near-Earth objects (NEOs) beginning circa 2025 - 2030 is one of the stated objectives of U.S. National Space Policy. Piloted missions to these bodies would further development of deep space mission systems and technologies, obtain better understanding of the origin and evolution of our Solar System, and support research for asteroid deflection and hazard mitigation strategies. This presentation will discuss some of the physical characteristics of NEOs and review some of the current plans for NEO research and exploration from both a human and robotic mission perspective.
How Many Ultra-Low Delta-v Near Earth Objects Remain Undiscovered? Implications for missions.

NASA Astrophysics Data System (ADS)

Elvis, Martin; Ranjan, Sukrit; Galache, Jose Luis; Murphy, Max

2015-08-01

The past decade has witnessed considerable growth of interest in missions to Near-Earth Objects (NEOs). NEOs are considered prime targets for manned and robotic missions, for both scientific objectives as well as in-situ resource utilization including harvesting of water for propellant and life support and mining of high-value elements for sale on Earth. Appropriate targets are crucial to such missions. Hence, ultra-low delta-v mission targets are strongly favored. Some mission architectures rely on the discovery of more ultra-low delta-v NEOs. In fact the approved and executed NEO missions have all targeted asteroids with ultra-low LEO to asteroid rendezvous delta-v <5.5 km/s.In this paper, we estimate the total NEO population as a function of delta-v, and how many remain to be discovered in various size ranges down to ~100m. We couple the NEOSSat-1 model (Greenstreet et al., 2012) to the NEO size distribution derived from the NEOWISE survey (Mainzer et al., 2011b) to compute an absolute NEO population model. We compare the Minor Planet Center (MPC) catalog of known NEOs to this NEO population model. We compute the delta-v from LEO to asteroid rendezvous orbits using a modified Shoemaker-Helin (S-H) formalism that empirically removes biases found comparing S-H with the results from NHATS. The median delta-v of the known NEOs is 7.3 km/s, the median delta-v predicted by our NEO model is 9.8 km/s, suggesting that undiscovered objects are biased to higher delta-v. The survey of delta-v <10.3 km/s NEOs is essentially complete for objects with diameter D >300 m. However, there are tens of thousands of objects with delta-v <10.3 km/s to be discovered in the D = 50 - 300 m size class (H = 20.4 - 24.3). Our work suggests that there are 100 yet-undiscovered NEOs with delta-v < 5:8 km/s, and 1000 undiscovered NEOs with v < 6.3 km/s. We conclude that, even with complete NEO surveys, the selection of good (i.e. ultra-low delta-v) mission targets is limited given current propulsion technology. Visiting the full range of NEO sub-types will likely require improved propulsion systems.
Near-Earth Objects. Chapter 27

NASA Technical Reports Server (NTRS)

Harris, Alan W.; Drube, Line; McFadden, Lucy A.; Binzel, Richard P.

2014-01-01

A near-Earth object (NEO) is an asteroid or comet orbiting the Sun with a perihelion distance of less than 1.3 Astronomical Units (AU) (1 AU, an astronomical unit, is the mean distance between the Earth and the Sun, around 150 million kilometers). If the orbit of an NEO can bring it to within 0.05 AU of the Earth's orbit, and it is larger than about 120 meters, it is termed a potentially hazardous object (PHO); an object of this size is likely to survive passage through the atmosphere and cause extensive damage on impact. (The acronyms NEA and PHO are used when referring specifically to asteroids.)
The LCOGT Near Earth Object (NEO) Follow-up Network

NASA Astrophysics Data System (ADS)

Lister, Tim; Gomez, Edward; Christensen, Eric; Larson, Steve

2014-11-01

Las Cumbres Observatory Global Telescope (LCOGT) network is a planned homogeneous network of over 35 telescopes at 6 locations in the northern and southern hemispheres. This network is versatile and designed to respond rapidly to target of opportunity events and also to do long term monitoring of slowly changing astronomical phenomena. The global coverage of the network and the apertures of telescope available make LCOGT ideal for follow-up and characterization of Solar System objects (e.g. asteroids, Kuiper Belt Objects, comets, Near-Earth Objects (NEOs)) and ultimately for the discovery of new objects.LCOGT has completed the first phase of the deployment with the installation and commissioning of nine 1-meter telescopes at McDonald Observatory (Texas), Cerro Tololo (Chile), SAAO (South Africa) and Siding Spring Observatory (Australia). The telescope network is now operating and observations are being executed remotely and robotically.I am using the LCOGT network to confirm newly detected NEO candidates produced by the major sky surveys such as Catalina Sky Survey (CSS), NEOWISE and PanSTARRS (PS1). Over 600 NEO candidates have been targeted so far this year with 250+ objects reported to the MPC, including 70 confirmed NEOs. An increasing amount of time is being spent to obtain follow-up astrometry and photometry for radar-targeted objects in order to improve the orbits and determine the rotation periods. This will be extended to obtain more light curves of other NEOs which could be Near-Earth Object Human Space Flight Accessible Targets Study (NHATS) or Asteroid Retrieval Mission (ARM) targets. Recent results have included the first period determination for the Apollo 2002 NV16 and our first NEO spectrum from the FLOYDS spectrographs on the LCOGT 2m telescopes obtained for 2012 DA14 during the February 2013 closepass.
The population of natural Earth satellites

NASA Astrophysics Data System (ADS)

Granvik, Mikael; Vaubaillon, Jeremie; Jedicke, Robert

2012-03-01

We have for the first time calculated the population characteristics of the Earth’s irregular natural satellites (NESs) that are temporarily captured from the near-Earth-object (NEO) population. The steady-state NES size-frequency and residence-time distributions were determined under the dynamical influence of all the massive bodies in the Solar System (but mainly the Sun, Earth, and Moon) for NEOs of negligible mass. To this end, we compute the NES capture probability from the NEO population as a function of the latter’s heliocentric orbital elements and combine those results with the current best estimates for the NEO size-frequency and orbital distribution. At any given time there should be at least one NES of 1-m diameter orbiting the Earth. The average temporarily-captured orbiter (TCO; an object that makes at least one revolution around the Earth in a co-rotating coordinate system) completes (2.88 ± 0.82) rev around the Earth during a capture event that lasts (286 ± 18) d. We find a small preference for capture events starting in either January or July. Our results are consistent with the single known natural TCO, 2006 RH120, a few-meter diameter object that was captured for about a year starting in June 2006. We estimate that about 0.1% of all meteors impacting the Earth were TCOs.
Exploration Roadmap Working Group (ERWG) Data Collection, NASA's Inputs

NASA Technical Reports Server (NTRS)

Drake, Bret; Landis, Rob; Thomas, Andrew; Mauzy, Susan; Graham, Lee; Culbert, Chris; Troutman, Pat

2010-01-01

This slide presentation reviews four areas for further space exploration: (1) Human Exploration of Mars Design Reference Architecture (DRA) 5.0, (2) Robotic Precursors targeting Near Earth Objects (NEO) for Human Exploration, (3) Notional Human Exploration of Near Earth Objects and (4) Low Earth Orbit (LEO) Refueling to Augment Human Exploration. The first presentation reviews the goals and objectives of the Mars DRA, presents a possible mission profile, innovation requirements for the mission and key risks and challenges for human exploration of Mars. The second presentation reviews the objective and goals of the robotic precursors to the NEO and the mission profile of such robotic exploration. The third presentation reviews the mission scenario of human exploration of NEO, the objectives and goals, the mission operational drivers, the key technology needs and a mission profile. The fourth and last presentation reviews the examples of possible refueling in low earth orbit prior to lunar orbit insertion, to allow for larger delivered payloads for a lunar mission.
The Mission Accessible Near-Earth Objects Survey (MANOS): photometric results

NASA Astrophysics Data System (ADS)

Thirouin, Audrey; Moskovitz, Nicholas; Binzel, Richard; Christensen, Eric J.; DeMeo, Francesca; Person, Michael J.; Polishook, David; Thomas, Cristina; Trilling, David E.; Willman, Mark; Hinkle, Mary L.; Burt, Brian; Avner, Dan

2016-10-01

The Mission Accessible Near-Earth Object Survey (MANOS) is a physical characterization survey of Near-Earth Objects (NEOs) to provide physical data for several hundred mission accessible NEOs across visible and near-infrared wavelengths. Using a variety of 1-m to 8-m class telescopes, we observe 5 to 10 newly discovered sub-km NEOs per month in order to derive their rotational properties and taxonomic class.Rotational data can provide useful information about physical properties, like shape, surface heterogeneity/homogeneity, density, internal structure, and internal cohesion. Here, we present results of the MANOS photometric survey for more than 200 NEOs. We report lightcurves from our first three years of observing and show objects with rotational periods from a couple of hours down to a few seconds. MANOS found the three fastest rotators known to date with rotational periods below 20s. A physical interpretation of these ultra-rapid rotators is that they are bound through a combination of cohesive and/or tensile strength rather than gravity. Therefore, these objects are important to understand the internal structure of NEOs. Rotational properties are used for statistical study to constrain overall properties of the NEO population. We also study rotational properties according to size, and dynamical class. Finally, we report a sample of NEOs that are fully characterized (lightcurve and visible spectra) as the most suitable candidates for a future robotic or human mission. Viable mission targets are objects with a rotational period >1h, and a delta-v lower than 12 km/s. Assuming the MANOS rate of object characterization, and the current NEO population estimates by Tricarico (2016), and by Harris and D'Abramo (2015), 10,000 to 1,000,000 NEOs with diameters between 10m and 1km are expected to be mission accessible. We acknowledge funding support from NASA NEOO grant number NNX14AN82G, and NOAO survey program.

Sentry: An Automated Close Approach Monitoring System for Near-Earth Objects

NASA Astrophysics Data System (ADS)

Chamberlin, A. B.; Chesley, S. R.; Chodas, P. W.; Giorgini, J. D.; Keesey, M. S.; Wimberly, R. N.; Yeomans, D. K.

2001-11-01

In response to international concern about potential asteroid impacts on Earth, NASA's Near-Earth Object (NEO) Program Office has implemented a new system called ``Sentry'' to automatically update the orbits of all NEOs on a daily basis and compute Earth close approaches up to 100 years into the future. Results are published on our web site (http://neo.jpl.nasa.gov/) and updated orbits and ephemerides made available via the JPL Horizons ephemeris service (http://ssd.jpl.nasa.gov/horizons.html). Sentry collects new and revised astrometric observations from the Minor Planet Center (MPC) via their electronic circulars (MPECs) in near real time as well as radar and optical astrometry sent directly from observers. NEO discoveries and identifications are detected in MPECs and processed appropriately. In addition to these daily updates, Sentry synchronizes with each monthly batch of MPC astrometry and automatically updates all NEO observation files. Daily and monthly processing of NEO astrometry is managed using a queuing system which allows for manual intervention of selected NEOs without interfering with the automatic system. At the heart of Sentry is a fully automatic orbit determination program which handles outlier rejection and ensures convergence in the new solution. Updated orbital elements and their covariances are published via Horizons and our NEO web site, typically within 24 hours. A new version of Horizons, in development, will allow computation of ephemeris uncertainties using covariance data. The positions of NEOs with updated orbits are numerically integrated up to 100 years into the future and each close approach to any perturbing body in our dynamic model (all planets, Moon, Ceres, Pallas, Vesta) is recorded. Significant approaches are flagged for extended analysis including Monte Carlo studies. Results, such as minimum encounter distances and future Earth impact probabilities, are published on our NEO web site.
A Space-Based Near-Earth Object Survey Telescope in Support of Human Exploration, Solar System Science, and Planetary Defense

NASA Technical Reports Server (NTRS)

Abell, Paul A.

2011-01-01

Human exploration of near-Earth objects (NEOs) beginning in 2025 is one of the stated objectives of U.S. National Space Policy. Piloted missions to these bodies would further development of deep space mission systems and technologies, obtain better understanding of the origin and evolution of our Solar System, and support research for asteroid deflection and hazard mitigation strategies. As such, mission concepts have received much interest from the exploration, science, and planetary defense communities. One particular system that has been suggested by all three of these communities is a space-based NEO survey telescope. Such an asset is crucial for enabling affordable human missions to NEOs circa 2025 and learning about the primordial population of objects that could present a hazard to the Earth in the future.
Scientific Exploration of Near-Earth Objects via the Crew Exploration Vehicle

NASA Technical Reports Server (NTRS)

Abell, P. A.; Korsmeyer, D. J.; Landis, R. R.; Lu, E.; Adamo, D.; Jones, T.; Lemke, L.; Gonzales, A.; Gershman, B.; Morrison, D.;

2007-01-01

The concept of a crewed mission to a near-Earth object (NEO) has been previously analyzed several times in the past. A more in depth feasibility study has been sponsored by the Advanced Projects Office within NASA's Constellation Program to examine the ability of a Crew Exploration Vehicle (CEV) to support a mission to a NEO. The national mission profile would involve a crew of 2 or 3 astronauts on a 90 to 120 day mission, which would include a 7 to 14 day stay for proximity operations at the target NEO.

Strategy for NEO follow-up observations

NASA Astrophysics Data System (ADS)

Tichy, Milos; Honkova, Michaela; Ticha, Jana; Kocer, Michal

2015-03-01

The Near-Earth Objects (NEOs) belong to the most important small bodies in the solar system, having the capability of close approaches to the Earth and even possibility to collide with the Earth. In fact, it is impossible to calculate reliable orbit of an object from a single night observations. Therefore it is necessary to extend astrometry dataset by early follow-up astrometry. Follow-up observations of the newly discovered NEO candidate should be done over an arc of several hours after the discovery and should be repeated over several following nights. The basic service used for planning of the follow-up observations is the NEO Confirmation Page (NEOCP) maintained by the Minor Planet Center of the IAU. This service provides on-line tool for calculating geocentric and topocentic ephemerides and sky-plane uncertainty maps of these objects at the specific date and time. Uncertainty map is one of the most important information used for planning of follow-up observation strategy for given time, indicating also the estimated distance of the newly discovered object and including possibility of the impact. Moreover, observatories dealing with NEO follow-up regularly have prepared their special tools and systems for follow-up work. The system and strategy for the NEO follow-up observation used at the Klet Observatory are described here. Methods and techniques used at the Klet NEO follow-up CCD astrometric programme, using 1.06-m and 0.57-m telescopes, are also discussed.
Feasibility study for near-earth-object tracking by a piggybacked micro-satellite with penetrators

NASA Astrophysics Data System (ADS)

Weiss, P.; Leung, W.; Yung, K. L.

2010-05-01

As of August 2007, over 5000 near-earth-objects (NEO) have been discovered. Some already represent a potential danger to the Earth while others might become hazards in the future. The Planetary Society organised in 2007 the "Apophis Mission Design Competition" in response to this potential threat with the objective to identify promising concepts to track NEOs; the asteroid 99942 Apophis was taken as the study case. This paper describes the "Houyi" proposal which was evaluated by the competition jury as an innovative approach to this problem. Instead of launching a large satellite for NEO tracking, this novel concept proposes a miniaturized satellite that is piggybacked onto a larger (scientific) mission. Such mission design would drastically reduce the costs for NEO surveillance. The presented scenario uses the ESA's SOLO mission as a design baseline for the piggyback option. This paper summarizes the architecture of this CubeSat towards Apophis and extends the previous study by focusing on the feasibility of a piggybacked mission in terms of propulsion requirements.
The Size Distribution of Near-Earth Objects Larger Than 10 m

NASA Astrophysics Data System (ADS)

Trilling, D. E.; Valdes, F.; Allen, L.; James, D.; Fuentes, C.; Herrera, D.; Axelrod, T.; Rajagopal, J.

2017-10-01

We analyzed data from the first year of a survey for Near-Earth Objects (NEOs) that we are carrying out with the Dark Energy Camera (DECam) on the 4 m Blanco telescope at the Cerro Tololo Inter-American Observatory. We implanted synthetic NEOs into the data stream to derive our nightly detection efficiency as a function of magnitude and rate of motion. Using these measured efficiencies and the solar system absolute magnitudes derived by the Minor Planet Center for the 1377 measurements of 235 unique NEOs detected, we directly derive, for the first time from a single observational data set, the NEO size distribution from 1 km down to 10 m. We find that there are {10}6.6 NEOs larger than 10 m. This result implies a factor of 10 fewer small NEOs than some previous results, though our derived size distribution is in good agreement with several other estimates.
Survey of Technologies Relevant to Defense From Near-Earth Objects

NASA Technical Reports Server (NTRS)

Adams, R. B.; Alexander, R.; Bonometti, J.; Chapman, J.; Fincher, S.; Hopkins, R.; Kalkstein, M.; Polsgrove, T.; Statham, G.; White, S.

2004-01-01

Several recent near-miss encounters with asteroids and comets have focused attention on the threat of a catastrophic impact with the Earth. This Technical Publication reviews the historical impact record and current understanding of the number and location of near-Earth objects (NEOs) to address their impact probability. Various ongoing projects intended to survey and catalog the NEO population are also reviewed. Details are given of a Marshall Space Flight Center-led study intended to develop and assess various candidate systems for protection of the Earth against NEOs. Details of analytical tools, trajectory tools, and a tool that was created to model both the undeflected inbound path of an NEO as well as the modified, postdeflection path are given. A representative selection of these possible options was modeled and evaluated. It is hoped that this study will raise the level of attention about this very real threat and also demonstrate that successful defense is both possible and practicable, provided appropriate steps are taken.
Results from the LCOGT Near-Earth Object Follow-up Network

NASA Astrophysics Data System (ADS)

Greenstreet, Sarah; Lister, Tim; Gomez, Edward; Christensen, Eric; Larson, Steve

2015-11-01

Las Cumbres Observatory Global Telescope Network (LCOGT) has deployed a homogeneous telescope network of nine 1-meter and two 2-meter telescopes to five locations in the northern and southern hemispheres, with plans to extend to twelve 1-meter telescopes at 6 locations. The versitility and design of this network allows for rapid response to target of opportunity events as well as the long-term monitoring of slowly changing astronomical phenomena. The network's global coverage and the apertures of telescopes available make LCOGT ideal for follow-up and characterization of Solar System objects (e.g. asteroids, Kuiper Belt Objects, comets, Near-Earth Objects (NEOs)) and ultimately for the discovery of new objects.LCOGT has completed the first phase of the deployment with the installation and commissioning of the nine 1-meter telescopes at McDonald Observatory (Texas), Cerro Tololo (Chile), SAAO (South Africa) and Siding Spring Observatory (Australia). This is complimented by the two 2-meter telescopes at Haleakala (Hawaii) and Siding Spring Observatory. The telescope network has been fully operational since May 2014, and observations are being executed remotely and robotically. Future expansion to sites in the Canary Islands and Tibet are planned for 2016.The LCOGT near-Earth object group is using the network to confirm newly detected NEO candidates produced by the major sky surveys such as Catalina Sky Survey (CSS), PanSTARRS (PS1) and NEOWISE, with several hundred targets being followed per year. Follow-up astrometry and photometry of radar-targeted objects and those on the Near-Earth Object Human Space Flight Accessible Targets Study (NHATS) or Asteroid Retrieval Mission (ARM) lists are improving orbits, producing light curves and rotation periods, and better characterizing these NEOs. Recent results include the first period determinations for several of the Goldstone-targeted NEOs. In addition, we are in the process of building a NEO portal that will allow professionals, amateurs, and Citizen Scientists to plan, schedule, and analyze NEO imaging and spectroscopy observations and data using the LCOGT Network and to act as a coordination hub for the NEO follow-up efforts.
Planetary Defense. Department of Defense Cost for the Detection, Exploration, and Rendezvous Mission of Near-Earth Objects

DTIC Science & Technology

1997-01-01

or even impact the Earth. In the past 15 years, research on NEOs has dra mati cally increased as astrono mers and ge olo gists real ize the Earth...fig. 7). In 1989, astrono mers discov ered an aster oid labeled 1989FC after its closest approach to Earth. This illus trates a disturb ing fact...Cur rently only astrono mers on shoestring, aca demic budgets are trying to locate and track NEOs, making esti mates of NEO popu la tions very impre
Energetic Techniques For Planetary Defense

NASA Astrophysics Data System (ADS)

Barbee, B.; Bambacus, M.; Bruck Syal, M.; Greenaugh, K. C.; Leung, R. Y.; Plesko, C. S.

2017-12-01

Near-Earth Objects (NEOs) are asteroids and comets whose heliocentric orbits tend to approach or cross Earth's heliocentric orbit. NEOs of various sizes periodically collide with Earth, and efforts are currently underway to discover, track, and characterize NEOs so that those on Earth-impacting trajectories are discovered far enough in advance that we would have opportunities to deflect or destroy them prior to Earth impact, if warranted. We will describe current efforts by the National Aeronautics and Space Administration (NASA) and the National Nuclear Security Administration (NNSA) to assess options for energetic methods of deflecting or destroying hazardous NEOs. These methods include kinetic impactors, which are spacecraft designed to collide with an NEO and thereby alter the NEO's trajectory, and nuclear engineering devices, which are used to rapidly vaporize a layer of NEO surface material. Depending on the amount of energy imparted, this can result in either deflection of the NEO via alteration of its trajectory, or robust disruption of the NEO and dispersal of the remaining fragments. We have studied the efficacies and limitations of these techniques in simulations, and have combined the techniques with corresponding spacecraft designs and mission designs. From those results we have generalized planetary defense mission design strategies and drawn conclusions that are applicable to a range of plausible scenarios. We will present and summarize our research efforts to date, and describe approaches to carrying out planetary defense missions with energetic NEO deflection or disruption techniques.
Small Solar Electric Propulsion Spacecraft Concept for Near Earth Object and Inner Solar System Missions

NASA Technical Reports Server (NTRS)

Lang, Jared J.; Randolph, Thomas M.; McElrath, Timothy P.; Baker, John D.; Strange, Nathan J.; Landau, Damon; Wallace, Mark S.; Snyder, J. Steve; Piacentine, Jamie S.; Malone, Shane;

2011-01-01

Near Earth Objects (NEOs) and other primitive bodies are exciting targets for exploration. Not only do they provide clues to the early formation of the universe, but they also are potential resources for manned exploration as well as provide information about potential Earth hazards. As a step toward exploration outside Earth's sphere of influence, NASA is considering manned exploration to Near Earth Asteroids (NEAs), however hazard characterization of a target is important before embarking on such an undertaking. A small Solar Electric Propulsion (SEP) spacecraft would be ideally suited for this type of mission due to the high delta-V requirements, variety of potential targets and locations, and the solar energy available in the inner solar system.Spacecraft and mission trades have been performed to develop a robust spacecraft design that utilizes low cost, off-the-shelf components that could accommodate a suite of different scientific payloads for NEO characterization. Mission concepts such as multiple spacecraft each rendezvousing with different NEOs, single spacecraft rendezvousing with separate NEOs, NEO landers, as well as other inner solar system applications (Mars telecom orbiter) have been evaluated. Secondary launch opportunities using the Expendable Secondary Payload Adapter (ESPA) Grande launch adapter with unconstrained launch dates have also been examined.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thirouin, A.; Moskovitz, N.; Burt, B.

The Mission Accessible Near-Earth Objects Survey aims to physically characterize sub-km near-Earth objects (NEOs). We report the first photometric results from the survey that began in 2013 August. Photometric observations were performed using 1–4 m class telescopes around the world. We present rotational periods and light curve amplitudes for 86 sub-km NEOs, though in some cases only lower limits are provided. Our main goal is to obtain light curves for small NEOs (typically, sub-km objects) and estimate their rotational periods, light curve amplitudes, and shapes. These properties are used for a statistical study to constrain overall properties of the NEOmore » population. A weak correlation seems to indicate that smaller objects are more spherical than larger ones. We also report seven NEOs that are fully characterized (light curve and visible spectra) as the most suitable candidates for a future human or robotic mission. Viable mission targets are objects fully characterized, with Δ v {sup NHATS} ≤ 12 km s{sup −1}, and a rotational period P > 1 hr. Assuming a similar rate of object characterization as reported in this paper, approximately 1230 NEOs need to be characterized in order to find 100 viable mission targets.« less
Near-Earth Objects: Targets for Future Human Exploration, Solar System Science, Resource Utilization, and Planetary Defense

NASA Technical Reports Server (NTRS)

Abell, Paul A.

2011-01-01

U.S. President Obama stated on April 15, 2010 that the next goal for human spaceflight will be to send human beings to a near-Earth asteroid by 2025. Given this direction from the White House, NASA has been involved in studying various strategies for near-Earth object (NEO) exploration in order to follow U.S. Space Exploration Policy. This mission would be the first human expedition to an interplanetary body beyond the Earth-Moon system and would prove useful for testing technologies required for human missions to Mars and other Solar System destinations. Missions to NEOs would undoubtedly provide a great deal of technical and engineering data on spacecraft operations for future human space exploration while conducting in-depth scientific investigations of these primitive objects. In addition, the resulting scientific investigations would refine designs for future extraterrestrial resource extraction and utilization, and assist in the development of hazard mitigation techniques for planetary defense. This presentation will discuss some of the physical characteristics of NEOs and review some of the current plans for NEO research and exploration from both a human and robotic mission perspective.
How to Communicate Near Earth Objects with the Public - Klet Observatory Experience

NASA Astrophysics Data System (ADS)

Ticha, Jana; Tichy, Milos; Kocer, Michal

2015-08-01

Near-Earth Object (NEO) research is counted among the most popular parts of communicating astronomy with the public. Increasing research results in the field of Near-Earth Objects as well as impact hazard investigations cause growing interest among general public and media. Furthermore NEO related issues have outstanding educational value. So thus communicating NEO detection, NEO characterization, possible impact effects, space missions to NEOs, ways of mitigation and impact warnings with the public and media belong to the most important tasks of scientists and research institutions.Our institution represents an unique liaison of the small professional research institution devoted especially to NEO studies (the Klet Observatory, Czech Republic) and the educational and public outreach branch (the Observatory and Planetarium Ceske Budejovice, Czech Republic). This all has been giving us an excellent opportunity for bringing NEO information to wider audience. We have been obtaining a wide experience in communicating NEOs with the public more than twenty years.There is a wide spectrum of public outreach tools aimed to NEO research and hazard. As the most useful ones we consider two special on-line magazines (e-zins) devoted to asteroids (www.planetky.cz) and comets (www.komety.cz) in Czech language, educational multimedia presentations for schools at different levels in planetarium, summer excursions for wide public just at the Klet Observatory on the top of the Klet mountain, public lectures, meetings and exhibitions. It seems to be very contributing and favoured by public to have opportunities for more or less informal meetings just with NEO researchers from time to time. Very important part of NEO public outreach consists of continuous contact with journalists and media including press releases, interviews, news, periodical programs. An increasing role of social media is taken into account through Facebook and Twitter profiles.The essential goal of all mentioned NEO public communication and educational tools is to bring relevant, clear, comprehensive and up to date information to students, educators, wide public and media.
Multiple NEO Rendezvous Using Solar Sails

NASA Technical Reports Server (NTRS)

Johnson, Les; Alexander, Leslie; Fabisinski, Leo; Heaton, Andy; Miernik, Janie; Stough, Rob; Wright, Roosevelt; Young, Roy

2012-01-01

Mission concept is to assess the feasibility of using solar sail propulsion to enable a robotic precursor that would survey multiple Near Earth Objects (NEOs) for potential future human visits. Single spacecraft will rendezvous with and image 3 NEOs within 6 years of launch
Near-Earth Object Survey Simulation Software

NASA Astrophysics Data System (ADS)

Naidu, Shantanu P.; Chesley, Steven R.; Farnocchia, Davide

2017-10-01

There is a significant interest in Near-Earth objects (NEOs) because they pose an impact threat to Earth, offer valuable scientific information, and are potential targets for robotic and human exploration. The number of NEO discoveries has been rising rapidly over the last two decades with over 1800 being discovered last year, making the total number of known NEOs >16000. Pan-STARRS and the Catalina Sky Survey are currently the most prolific NEO surveys, having discovered >1600 NEOs between them in 2016. As next generation surveys such as Large Synoptic Survey Telescope (LSST) and the proposed Near-Earth Object Camera (NEOCam) become operational in the next decade, the discovery rate is expected to increase tremendously. Coordination between various survey telescopes will be necessary in order to optimize NEO discoveries and create a unified global NEO discovery network. We are collaborating on a community-based, open-source software project to simulate asteroid surveys to facilitate such coordination and develop strategies for improving discovery efficiency. Our effort so far has focused on development of a fast and efficient tool capable of accepting user-defined asteroid population models and telescope parameters such as a list of pointing angles and camera field-of-view, and generating an output list of detectable asteroids. The software takes advantage of the widely used and tested SPICE library and architecture developed by NASA’s Navigation and Ancillary Information Facility (Acton, 1996) for saving and retrieving asteroid trajectories and camera pointing. Orbit propagation is done using OpenOrb (Granvik et al. 2009) but future versions will allow the user to plug in a propagator of their choice. The software allows the simulation of both ground-based and space-based surveys. Performance is being tested using the Grav et al. (2011) asteroid population model and the LSST simulated survey “enigma_1189”.
Suborbital Asteroid Intercept and Fragmentation for Very Short Warning Time Scenarios

NASA Technical Reports Server (NTRS)

Hupp, Ryan; Dewald, Spencer; Wie, Bong; Barbee, Brent W.

2015-01-01

Small near-Earth objects (NEOs) 50150 m in size are far more numerous (hundreds of thousands to millions yet to be discovered) than larger NEOs. Small NEOs, which are mostly asteroids rather than comets, are very faint in the night sky due to their small sizes, and are, therefore, difficult to discover far in advance of Earth impact. However, even small NEOs are capable of creating explosions with energies on the order of tens or hundreds of megatons (Mt).We are, therefore, motivated to prepare to respond effectively to short warning time, small NEO impact scenarios. In this paper we explore the lower bound on actionable warning time by investigating the performance of notional upgraded Intercontinental Ballistic Missiles (ICBMs) to carry Nuclear Explosive Device (NED) payloads to intercept and disrupt a fictitious incoming NEO at high altitudes (generally, at least 2500 km above Earth). We conduct this investigation by developing optimal NEO intercept trajectories for a range of cases and comparing their performances.Our results show that suborbital NEO intercepts using Minuteman III or SM-3 IIA launch vehicles could achieve NEO intercept a few minutes prior to when the NEOwould strike Earth. We also find that more powerful versions of the launch vehicles (e.g., total V 9.511 kms) could intercept incoming NEOs over a day prior to when the NEO would strike Earth, if launched at least several days prior to the time of NEO intercept. Finally, we discuss a number of limiting factors and practicalities that affect whether the notional systems we describe could become feasible.
Threat Assessment of Small Near-Earth Objects

NASA Astrophysics Data System (ADS)

Ryan, E.; Ryan, W.

2010-09-01

Researchers at the Magdalena Ridge Observatory’s (MRO) 2.4-meter telescope facility are in their third year of a program to derive physical characterization information on some of the smallest (less than 200 meters in diameter) objects in the Near-Earth Object (NEO) population. Tiny comets and asteroids are being discovered by survey programs on a routine basis, so targets available for study have been abundant. Our primary objective is to derive rotation rates for these objects, and to place the results in context with previous data to enhance our understanding of asteroid impact physics and better address the threat from NEOs having Earth-crossing orbits. Rotation rate can be used to infer internal structure, which is a physical property important to assessing the energy needed for object disruption or other forms of hazard mitigation. Since the existing database of rotational data derived from lightcurves of objects in this small size regime is sparse, collection of additional observational data is beneficial. Acquiring more knowledge about the physical nature of NEOs not only contributes to general scientific pursuits, but is important to planetary defense.
Near-Earth Object Astrometric Interferometry

NASA Technical Reports Server (NTRS)

Werner, Martin R.

2005-01-01

Using astrometric interferometry on near-Earth objects (NEOs) poses many interesting and difficult challenges. Poor reflectance properties and potentially no significant active emissions lead to NEOs having intrinsically low visual magnitudes. Using worst case estimates for signal reflection properties leads to NEOs having visual magnitudes of 27 and higher. Today the most sensitive interferometers in operation have limiting magnitudes of 20 or less. The main reason for this limit is due to the atmosphere, where turbulence affects the light coming from the target, limiting the sensitivity of the interferometer. In this analysis, the interferometer designs assume no atmosphere, meaning they would be placed at a location somewhere in space. Interferometer configurations and operational uncertainties are looked at in order to parameterize the requirements necessary to achieve measurements of low visual magnitude NEOs. This analysis provides a preliminary estimate of what will be required in order to take high resolution measurements of these objects using interferometry techniques.
FIRST RESULTS FROM THE RAPID-RESPONSE SPECTROPHOTOMETRIC CHARACTERIZATION OF NEAR-EARTH OBJECTS USING UKIRT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mommert, M.; Trilling, D. E.; Petersen, E.

2016-04-15

Using the Wide Field Camera for the United Kingdom Infrared Telescope (UKIRT), we measure the near-infrared colors of near-Earth objects (NEOs) in order to put constraints on their taxonomic classifications. The rapid-response character of our observations allows us to observe NEOs when they are close to the Earth and bright. Here we present near-infrared color measurements of 86 NEOs, most of which were observed within a few days of their discovery, allowing us to characterize NEOs with diameters of only a few meters. Using machine-learning methods, we compare our measurements to existing asteroid spectral data and provide probabilistic taxonomic classificationsmore » for our targets. Our observations allow us to distinguish between S-complex, C/X-complex, D-type, and V-type asteroids. Our results suggest that the fraction of S-complex asteroids in the whole NEO population is lower than the fraction of ordinary chondrites in the meteorite fall statistics. Future data obtained with UKIRT will be used to investigate the significance of this discrepancy.« less

The NEOShield-2 EU Project - The Italian contribution

NASA Astrophysics Data System (ADS)

Ieva, Simone; Dotto, Elisabetta; Mazzotta Epifani, Elena; Di Paola, Andrea; Speziali, Roberto; Cortese, Matteo; Lazzarin, Monica; Bertini, Ivano; Magrin, Sara; Barucci, Maria Antonietta; Perna, Davide; Perozzi, Ettore; Micheli, Marco

2016-04-01

The Near Earth Object (NEO) population comprehends small bodies that periodically approach or intersect the Earth's orbit. NEOs could have possible impacts with the Earth and, whatever the scenario, their physical characterization is essential to define successful mitigation strategies. Moreover, their study is important per se, since they represent the closest remnants of the planetary formation, 4.5 billion years ago, and the knowledge of their physical properties allows us to put constraints on the formation and early evolution of the Solar System. On the basis of these considerations, the NEO population is an important target for ground-based studies. Unfortunately, less than 15% of the 13500 known NEOs has a physical characterization, showing a great diversity - in sizes, shapes, rotational periods, albedos, and composition - and their increasing discovery rate (currently ˜1500 objects/year) makes the situation progressively worse. At a European level, the European Commission promoted the study on NEOs by approving and financing the NEOShield-2 project (2015-2017) in the framework of the Horizon 2020 program. The aims of NEOShield-2 are: i) to study detailed technologies and instruments to conduct close approach missions to NEOs or to undertake mitigation demonstration, and ii) to retrieve the physical properties of a wide number of NEOs, in order to design impact mitigation missions and assess the consequences of an impact on Earth. The Italian contributors to the NEOShield-2 project (INAF-OAR and Padova University) are responsible for the Task 10.2.1 'Colours and Phase function'. The aim of this task is to acquire photometric measurements for a wide sample of NEOs in order to i) perform phase function analysis, ii) retrieve surface colors and iii) obtain a preliminary taxonomical classification. This activity is developed in close collaboration with the ESA SSA NEO Coordination Centre.
The Near Earth Object Scout Spacecraft: A Low Cost Approach to in-situ Characterization of the NEO Population

NASA Technical Reports Server (NTRS)

Koontz, Steven L.; Condon, Gerald; Graham, Lee; Bevilacqua, Ricardo

2014-01-01

In this paper we describe a micro/nano satellite spacecraft and a supporting mission profile and architecture designed to enable preliminary in-situ characterization of a significant number of Near Earth Objects (NEOs) at reasonable cost. The spacecraft will be referred to as the NEO Scout. NEO Scout spacecraft are to be placed in GTO, GEO, or cis-lunar space as secondary payloads on launch vehicles headed for GTO or beyond and will begin their mission after deployment from the launcher. A distinguishing key feature of the NEO scout system is to design the mission timeline and spacecraft to rendezvous with and land on the target NEOs during close approach to the Earth-Moon system using low-thrust/high- impulse propulsion systems. Mission feasibility and preliminary design analysis are presented along with detailed trajectory calculations. The use of micro/nano satellites in low-cost interplanetary exploration is attracting increasing attention and is the subject of several annual workshops and published design studies (1-4). The NEO population consists of those asteroids and short period comets orbiting the Sun with a perihelion of 1.3 astronomical units or less (5-8). As of July 30, 2013 10065 Near-Earth objects have been discovered. The spin rate, mass, density, surface physical (especially mechanical) properties, composition, and mineralogy of the vast majority of these objects are highly uncertain and the limited available telescopic remote sensing data imply a very diverse population (5-8). In-situ measurements by robotic spacecraft are urgently needed to provide the characterization data needed to support hardware and mission design for more ambitious human and robotic NEO operations. Large numbers of NEOs move into close proximity with the Earth-Moon system every year (9). The JPL Near-Earth Object Human Space Flight Accessible Targets Study (NHATS) (10) has produced detailed mission profile and delta V requirements for various NEO missions ranging from 30 to 420 days in duration and assuming chemical propulsion. Similar studies have been reported assuming high power electric propulsion for manned NEO rendezvous missions (11). The delta V requirement breakdown and mission profile data from references 10 and 11 are used as a basis for sizing the NEO Scout spacecraft and for conducting preliminary feasibility assessments using the Tsiokolvsky rocket equation, a (worst-case) delta V requirement of 10 km/sec, and a maximum spacecraft dry mass of 20 kg. Using chemical propellant for a 10 km/sec delta V drives spacecraft wet mass well above 300 kg so that chemical propulsion is a non-starter for the proposed mission profile and spacecraft wet mass limits. In contrast, a solar electric propulsion system needs only 8 kg of Xe propellant to accelerate the spacecraft to 10 km/sec in 163 days with 0.02 N of thrust and 500 W of power from1.6 sq m of 29% efficient solar panels. In a second example, accelerating a 4 kg payload to 7 km/sec over 180 days requires about 6.7 kg of propellant and 1.2 kg of solar panels (12 kg total spacecraft wet mass).
The Large Synoptic Survey Telescope: Projected Near-Earth Object Discovery Performance

NASA Technical Reports Server (NTRS)

Chesley, Steven R.; Veres, Peter

2016-01-01

The Large Synoptic Survey Telescope (LSST) is a large-aperture, wide-field survey that has the potential to detect millions of asteroids. LSST is under construction with survey operations slated to begin in 2022. We describe an independent study to assess the performance of LSST for detecting and cataloging near-Earth objects (NEOs). A significant component of the study will be to assess the survey's ability to link observations of a single object from among the large numbers of false detections and detections of other objects. We also will explore the survey's basic performance in terms of fraction of NEOs discovered and cataloged, both for the planned baseline survey, but also for enhanced surveys that are more carefully tuned for NEO search, generally at the expense of other science drivers. Preliminary results indicate that with successful linkage under the current baseline survey LSST would discover approximately 65% of NEOs with absolute magnitude H is less than 22, which corresponds approximately to 140m diameter.
The Mission Accessible Near-Earth Objects Survey (MANOS)

NASA Technical Reports Server (NTRS)

Abell, Paul; Moskovitz, Nicholas; DeMeo, Francesca; Endicott, Thomas; Busch, Michael; Roe, Henry; Trilling, David; Thomas, Cristina; Willman, Mark; Grundy, Will;

2013-01-01

Near-Earth objects (NEOs) are essential to understanding the origin of the Solar System. Their relatively small sizes and complex dynamical histories make them excellent laboratories for studying ongoing Solar System processes. The proximity of NEOs to Earth makes them favorable targets for space missions. In addition, knowledge of their physical properties is crucial for impact hazard assessment. However, in spite of their importance to science, exploration, and planetary defense, a representative sample of physical characteristics for sub-km NEOs does not exist. Here we present the Mission Accessible Near-Earth Objects Survey (MANOS), a multi-year survey of subkm NEOs that will provide a large, uniform catalog of physical properties (light curves + colors + spectra + astrometry), representing a 100-fold increase over the current level of NEO knowledge within this size range. This survey will ultimately characterize more than 300 mission-accessible NEOs across the visible and near-infrared ranges using telescopes in both the northern and southern hemispheres. MANOS has been awarded 24 nights per semester for the next three years on NOAO facilities including Gemini North and South, the Kitt Peak Mayall 4m, and the SOAR 4m. Additional telescopic assets available to our team include facilities at Lowell Observatory, the University of Hawaii 2.2m, NASA's IRTF, and the Magellan 6.5m telescopes. Our focus on sub-km sizes and mission accessibility (dv < 7 km/s) is a novel approach to physical characterization studies and is possible through a regular cadence of observations designed to access newly discovered NEOs within days or weeks of first detection before they fade beyond observational limits. The resulting comprehensive catalog will inform global properties of the NEO population, advance scientific understanding of NEOs, produce essential data for robotic and spacecraft exploration, and develop a critical knowledge base to address the risk of NEO impacts. We intend to conduct this survey with complete transparency, publicly sharing our target lists and survey progress. We invite collaborative uses for these data as a way to broaden the scientific impact of this survey.

Suborbital Intercept and Fragmentation of an Asteroid with Very Short Warning Time Scenario

NASA Technical Reports Server (NTRS)

Hupp, Ryan; DeWald, Spencer; Wie, Bong; Barbee, Brent W.

2015-01-01

Small near-Earth objects (NEOs) is approx. 50-150 m in size are far more numerous (hundreds of thousands to millions yet to be discovered) than larger NEOs. Small NEOs, which are mostly asteroids rather than comets, are very faint in the night sky due to their small sizes, and are, therefore, difficult to discover far in advance of Earth impact. Furthermore, even small NEOs are capable of creating explosions with energies on the order of tens or hundreds of megatons (Mt). We are, therefore, motivated to prepare to respond effectively to short warning time, small NEO impact scenarios. In this paper we explore the lower bound on actionable warning time by investigating the performance of notional upgraded Intercontinental Ballistic Missiles (ICBMs) to carry Nuclear Explosive Device (NED) payloads to intercept and disrupt a hypothetical incoming NEO at high altitudes (generally at least 2500 km above Earth). We conduct this investigation by developing optimal NEO intercept trajectories for a range of cases and comparing their performances. Our results show that suborbital NEO intercepts using Minuteman III or SM-3 IIA launch vehicles could achieve NEO intercept a few minutes prior to when the NEO would strike Earth. We also find that more powerful versions of the launch vehicles (e.g., total deltaV is approx. 9.5-11 km/s) could intercept incoming NEOs several hours prior to when the NEO would strike Earth, if launched at least several days prior to the time of intercept. Finally, we discuss a number of limiting factors and practicalities that affect whether the notional systems we describe could become feasible.
Mission Design and Analysis for Suborbital Intercept and Fragmentation of an Asteroid with Very Short Warning Time

NASA Technical Reports Server (NTRS)

Hupp, Ryan; DeWald, Spencer; Wie, Bong; Barbee, Brent W.

2014-01-01

Small near-Earth objects (NEOs) approximately 50-150 m in size are far more numerous (hundreds of thousands to millions yet to be discovered) than larger NEOs. Small NEOs, which are mostly asteroids rather than comets, are very faint in the night sky due to their small sizes, and are, therefore, difficult to discover far in advance of Earth impact. Furthermore, even small NEOs are capable of creating explosions with energies on the order of tens or hundreds of megatons (Mt). We are, therefore, motivated to prepare to respond effectively to short warning time, small NEO impact scenarios. In this paper we explore the lower bound on actionable warning time by investigating the performance of notional upgraded Intercontinental Ballistic Missiles (ICBMs) to carry Nuclear Explosive Device (NED) payloads to intercept and disrupt a hypothetical incoming NEO at high altitudes (generally at least 2500 km above Earth). We conduct this investigation by developing optimal NEO intercept trajectories for a range of cases and comparing their performances. Our results show that suborbital NEO intercepts using Minuteman III or SM-3 IIA launch vehicles could achieve NEO intercept a few minutes prior to when the NEO would strike Earth. We also find that more powerful versions of the launch vehicles (e.g., total delta V of approximately 9.5-11 km/s) could intercept incoming NEOs several hours prior to when the NEO would strike Earth, if launched at least several days prior to the time of intercept. Finally, we discuss a number of limiting factors and practicalities that affect whether the notional systems we describe could become feasible.
Scientific Exploration of Near-Earth Objects via the Crew Exploration Vehicle

NASA Technical Reports Server (NTRS)

Abell, Paul A.; Korsmeyer, D. J.; Landis, R. R.; Lu, E.; Adamo (D.); Jones (T.); Lemke, L.; Gonzales, A.; Gershman, B.; Morrison, D.;

2007-01-01

The concept of a crewed mission to a Near-Earth Object (NEO) has been analyzed in depth in 1989 as part of the Space Exploration Initiative. Since that time two other studies have investigated the possibility of sending similar missions to NEOs. A more recent study has been sponsored by the Advanced Programs Office within NASA's Constellation Program. This study team has representatives from across NASA and is currently examining the feasibility of sending a Crew Exploration Vehicle (CEV) to a near-Earth object (NEO). The ideal mission profile would involve a crew of 2 or 3 astronauts on a 90 to 120 day flight, which would include a 7 to 14 day stay for proximity operations at the target NEO. One of the significant advantages of this type of mission is that it strengthens and validates the foundational infrastructure for the Vision for Space Exploration (VSE) and Exploration Systems Architecture Study (ESAS) in the run up to the lunar sorties at the end of the next decade (approx.2020). Sending a human expedition to a NEO, within the context of the VSE and ESAS, demonstrates the broad utility of the Constellation Program s Orion (CEV) crew capsule and Ares (CLV) launch systems. This mission would be the first human expedition to an interplanetary body outside of the cislunar system. Also, it will help NASA regain crucial operational experience conducting human exploration missions outside of low Earth orbit, which humanity has not attempted in nearly 40 years.

Near Earth Objects and Cascading Effects from the Policy Perspective: Implications from Problem and Solution Definition

NASA Astrophysics Data System (ADS)

Lindquist, Eric

2016-04-01

The characterization of near-Earth-objects (NEOs) in regard to physical attributes and potential risk and impact factors presents a complex and complicates scientific and engineering challenge. The societal and policy risks and impacts are no less complex, yet are rarely considered in the same context as material properties or related factors. Further, NEO impacts are typically considered as discrete events, not as initial events in a dynamic cascading system. The objective of this contribution is to position the characterization of NEOs within the public policy process domain as a means to reflect on the science-policy nexus in regard to risks and multi-hazard impacts associated with these hazards. This will be accomplished through, first, a brief overview of the science-policy nexus, followed by a discussion of policy process frameworks, such as agenda setting and the multiple streams model, focusing events, and punctuated equilibrium, and their application and appropriateness to the problem of NEOs. How, too, for example, does NEO hazard and risk compare with other low probability, high risk, hazards in regard to public policy? Finally, we will reflect on the implications of alternative NEO "solutions" and the characterization of the NEO "problem," and the political and public acceptance of policy alternatives as a way to link NEO science and policy in the context of the overall NH9.12 panel.
The Mission Accessible Near-Earth Object Survey (MANOS): Project Status

NASA Astrophysics Data System (ADS)

Moskovitz, Nicholas; Thirouin, Audrey; Mommert, Michael; Thomas, Cristina A.; Skiff, Brian; Polishook, David; Burt, Brian; Trilling, David E.; DeMeo, Francesca E.; Binzel, Richard P.; Christensen, Eric J.; Willman, Mark; Hinkle, Mary

2017-10-01

The Mission Accessible Near-Earth Object Survey (MANOS) is a physical characterization survey of sub-km, low delta-v, newly discovered near-Earth objects (NEOs). MANOS aims to collect astrometry, lightcurve photometry, and reflectance spectra for a representative sample of these important target of opportunity objects in a rarely observed size range. We employ a diverse set of large aperture (2-8 meter) telescopes and observing modes (queue, remote, classical) to overcome the challenge of observing faint NEOs moving at high non-sidereal rates with short observing windows. We target approximately 10% of newly discovered NEOs every month for follow-up characterization.The first generation MANOS ran from late 2013 to early 2017, using telescopes at Lowell Observatory, NOAO, and the University of Hawaii. This resulted in the collection of data for over 500 targets. These data are continuing to provide new insights into the NEO population as a whole as well as for individual objects of interest. Science highlights include identification of the four fastest rotating minor planets found to date with rotation periods under 20 seconds, constraints on the distribution of NEO morphologies as quantified by de-biased estimates for lightcurve-derived axis ratios, and the compositional distribution of NEOs at sizes under 100 meters.The second generation MANOS will begin in late 2017 and will employ much of the same strategies while continuing to build a comprehensive dataset of NEO physical properties. This will grow the MANOS sample to ~1000 objects and provide the means to better address key questions related to understanding the physical properties of NEOs, their viability as exploration mission targets, and their relationship to Main Belt asteroids and meteorites. This continuation of MANOS will include an increased focus on spectroscopic observations at near-IR wavelengths using a new instrument called NIHTS (the Near-Infrared High-Throughput Spectrograph) at Lowell Observatory’s 4.3m Discovery Channel Telescope.We will present key results from the first generation survey and current status and plans for the second generation survey. MANOS is supported by the NASA SSO/NEOO program.
Physical Characterization of the Near-Earth Object Population

NASA Technical Reports Server (NTRS)

Binzel, Richard P.

2003-01-01

This program seeks to address the fundamental question: What are the relationships between asteroids, comets, and meteorites? To answer this question, we are studying the population of asteroids near the Earth which likely contain both asteroids and extinct comets and which is the immediate source for meteorites. An analysis of new and existing visible wavelength spectral data for more than 100 (Near-Earth Objects) NEOs, and Keck albedo data for more than 20 NEOs is underway. New asteroid-meteorite links are being found, the NEO population and hazard is being characterized, and the extinct comet component is being constrained. These results are contained within the following publication work during the current period: 1 book, 2 book chapters, 1 published paper, 2 papers submitted, 2 papers in preparation, 1 Ph. D. thesis in preparation, and 7 meeting abstracts/presentations.
Near-Earth asteroids: Observer alert network and physical observations

NASA Technical Reports Server (NTRS)

Davis, Donald R.; Chapman, Clark R.

1992-01-01

This project strives to obtain physical observations on newly discovered Near-Earth Objects (NEO's) in order to provide fundamental data needed to assess the resources available in the population. The goal is acquiring data on all objects brighter than magnitude V= 17.0. To accomplish this, an electronic mail alert and observer information service that informs observers around the world as to the status of physical observations on currently observable NEO's was established. Such data is also acquired ourselves through a cooperative program with European colleagues that uses telescopes on La Palma to obtain spectra of NEO's and through observations made from a local telescope on Tumamoc Hill. This latter telescope has the advantage that large amounts of observing time are available, so that whenever a new NEO's discovered, we can be assured of getting time to observe it.
Optimization of deflection of a big NEO through impact with a small one.

PubMed

Zhu, Kaijian; Huang, Weiping; Wang, Yuncai; Niu, Wei; Wu, Gongyou

2014-01-01

Using a small near-Earth object (NEO) to impact a larger and potentially threatening NEO has been suggested as an effective method to avert a collision with Earth. This paper develops a procedure for analysis of the technique for specific NEOs. First, an optimization method is used to select a proper small body from the database. Some principles of optimality are achieved with the optimization process. Then, the orbit of the small body is changed to guarantee that it flies toward and impacts the big threatening NEO. Kinetic impact by a spacecraft is chosen as the strategy of deflecting the small body. The efficiency of this method is compared with that of a direct kinetic impact to the big NEO by a spacecraft. Finally, a case study is performed for the deflection of the Apophis NEO, and the efficiency of the method is assessed.
Optimization of Deflection of a Big NEO through Impact with a Small One

PubMed Central

Zhu, Kaijian; Huang, Weiping; Wang, Yuncai; Niu, Wei; Wu, Gongyou

2014-01-01

Using a small near-Earth object (NEO) to impact a larger and potentially threatening NEO has been suggested as an effective method to avert a collision with Earth. This paper develops a procedure for analysis of the technique for specific NEOs. First, an optimization method is used to select a proper small body from the database. Some principles of optimality are achieved with the optimization process. Then, the orbit of the small body is changed to guarantee that it flies toward and impacts the big threatening NEO. Kinetic impact by a spacecraft is chosen as the strategy of deflecting the small body. The efficiency of this method is compared with that of a direct kinetic impact to the big NEO by a spacecraft. Finally, a case study is performed for the deflection of the Apophis NEO, and the efficiency of the method is assessed. PMID:25525627
Lost Near-Earth Object Candidates

NASA Astrophysics Data System (ADS)

Veres, Peter; Farnocchia, Davide; Williams, Gareth; Keys, Sonia; Boardman, Ian; Holman, Matthew J.; Payne, Matthew J.

2017-10-01

The number of discovered Near-Earth Objects (NEOs) increases rapidly, currently exceeding 16,000 NEOs. 2016 was the most productive year ever with 1,888 NEO discoveries. The NEO discovery process typically begins with three to five detections of a previously unidentified object that are reported to the Minor Planet Center (MPC). According to the plane-of-sky motion, the MPC ranks all of the new candidate discoveries for the likelihood of being NEOs using the so-called digest score. If the digest score is greater than 65 the observations appear on the publicly accessible NEO Confirmation Page (NEOCP). Objects on the NEOCP are followed up in subsequent hours and days. When enough observations are collected to ensure that the object is real and that the orbit is determined, the NEO is officially announced with its new designation by a Minor Planet Electronic Circular. However, 14% of NEO candidates never get confirmed and are therefore lost due to the lack of follow-up observations. We analyzed the lost NEO candidates that appeared on NEOCP in 2013-2016 and investigated the reasons why they were not confirmed. In particular, we studied the properties of the lost NEO candidates with a digest score of 100 that were reported by the two most prolific discovery sites - Pan-STARRS1 (F51) and Mt. Lemmon Survey (G96). We derived their plane-of-sky positions and rates, brightness, and ephemeris uncertainties, and assessed correlations with the phase of the moon and seasonal effects apparent in the given observatory’s data. We concluded that lost NEO candidates typically have a larger rate of motion and larger uncertainties than those of confirmed objects. However, many of the lost candidates could be recovered. In fact, the 1-sigma plane-of-sky uncertainty was still within ±0.5 deg in 79% (F51) and 69% (G96) of the cases 24 hours after discovery and in 31% (F51) and 30% (G96) of the cases 48 hours after discovery. If all of the NEO candidates with a digest score of 100 had been followed up, the number of discovered NEOs would have been larger by 685+/-30 in 2013-2016. The measures to decrease the number of lost NEO candidates include improved uncertainty maps and uncertainties as function of time on the NEOCP.
Projected Near-Earth Object Discovery Performance of the Large Synoptic Survey Telescope

NASA Technical Reports Server (NTRS)

Chesley, Steven R.; Veres, Peter

2017-01-01

This report describes the methodology and results of an assessment study of the performance of the Large Synoptic Survey Telescope (LSST) in its planned efforts to detect and catalog near-Earth objects (NEOs).
Physical characterization of the near-Earth object population

NASA Astrophysics Data System (ADS)

Ieva, S.; Dotto, E.; Mazzotta Epifani, E.; Perna, D.; Perozzi, E.; Micheli, M.

2017-08-01

The Near-Earth Object (NEO) population, being the remnants of the building blocks that originally formed our solar system, allows us to understand the initial conditions that were present in the protosolar nebula. Its investigation can provide crucial information on the origin and early evolution of the solar system, and shed light on the delivery of water and organic-rich material to the early Earth. Furthermore, the possible impact of NEOs poses a serious hazard to our planet. There is an urgent need to undertake a comprehensive physical characterization of the NEO population, particularly for the ones with the higher likelihood of catastrophic impact with the Earth. One of the main aims of the NEOShield-2 project (2015-2017), financed by the European Commission in the framework of the HORIZON 2020 program, is to undertake an extensive observational campaign and provide a physical and compositional characterization for a large number of NEOs in the < 300 m size range, retrieving in particular their mitigation-relevant properties (size, shape, albedo, diameter, composition, internal structure, ...) in order to design impact mitigation missions and assess the consequences of an impact on Earth. We carried out visible photometric measurements for a sample of 158 uncharacterized NEOs. We also made use of visible and near-infrared spectroscopy to assess NEO composition and perform a mineralogical analysis. We found that carbonaceous C-complex asteroids deserve a special attention, since their physical structure ( e.g., primitive nature, porosity) and their orbital parameters (mainly the inclination) make at the moment challenging the design of a successful mitigation strategy. Indeed, the most advanced mitigation technique (the kinetic impactor) is less effective on these bodies, and the high inclination of some possible impactors require a launch vehicle capability beyond the one currently available.
Near-Earth-Object identification over apparitions using n-body ranging

NASA Astrophysics Data System (ADS)

Granvik, Mikael; Muinonen, Karri

2007-05-01

Earth-based telescopes can observe Near-Earth objects (NEOs) continuously for a few weeks or months during each apparition. Due to the usually complicated dynamics of the Sun-Earth-NEO triplet, the time interval between consecutive apparitions typically ranges from months to several years. On these timescales single-apparition sets of observations (SASs) having reasonably small observational time-intervals lead to substantial orbital uncertainties. The linking of SASs over apparitions thus becomes a nontrivial task. Of a total of roughly 4,100 NEO observation sets, or orbits, currently known, some 500 are SASs for which the observational time interval is less than 7 days. Either these SASs have not been observed at an apparition following the discovery apparition (some 40% of the above NEO SASs have been obtained in 2005 or later), or the linkage of SASs has failed, an option which should preferably be eliminated. As a continuation to our work on the short-arc linking problem at the discovery moment (Granvik and Muinonen, 2005, Icarus 179, p. 109), we have investigated the possibility of using a similar method for the linking of SASs over apparitions. Assuming that the observational time-interval for SASs of NEOs is typically at least one day (minimum requirement set by the Minor Planet Center), the orbital-element probability density function is constrained as compared to the typical short-arc case with an observational time interval of only a few tens of minutes. Because of the smaller orbital-element uncertainty, we can use the short-arc method (comparison in ephemeris space) for longer time spans, or even do the comparison directly in orbital-element space (Keplerian, equinoctial, etc.), thus allowing us to assess the problem of linking SASs of NEOs. We will present linking results by using both simulated and real NEO SASs.
A Low Risk Strategy for the Exploration of Near-Earth Objects

NASA Technical Reports Server (NTRS)

Landis, Rob R.

2011-01-01

The impetus for asteroid exploration is scientific, political, and pragmatic. The notion of sending human explorers to asteroids is not new. Piloted missions to these primitive bodies were first discussed in the 1960s, pairing Saturn V rockets with enhanced Apollo spacecraft to explore what were then called "Earth-approaching asteroids." Two decades ago, NASA's Space Exploration Initiative (SEI) also briefly examined the possibility of visiting these small celestial bodies. Most recently, the U.S. Human Space Flight Review Committee (the second Augustine Commission) suggested that near-Earth objects (NEOs) represent a target-rich environment for exploration via the "Flexible Path" option. However, prior to seriously considering human missions to NEOs, it has become clear that we currently lack a robust catalog of human accessible targets. The majority of the NEOs identified by a study team across several NASA centers as "human-accessible" are probably too small and have orbits that are too uncertain to consider mounting piloted expeditions to these small worlds. The first step in developing such a catalog is, therefore, to complete a space-based NEO survey. The resulting catalog of candidate NEOs would then be transformed into a matrix of opportunities for robotic and human missions for the next several decades. This initial step of a space-based NEO survey first is the linchpin to laying the foundation of a low-risk architecture to venture out and explore these primitive bodies. We suggest such a minimalist framework architecture from 1) extensive ground-based and precursor spacecraft investigations (while applying operational knowledge from science-driven robotic missions), 2) astronaut servicing of spacecraft operating at geosynchronous Earth orbit to retain essential skills and experience, and 3) applying the sum of these skills, knowledge and experience to piloted missions to NEOs.
The Pan-STARRS search for Near-Earth Objects

NASA Astrophysics Data System (ADS)

Wainscoat, Richard J.; Weryk, Robert; Chambers, Kenneth

2018-01-01

The Pan-STARRS1 telescope on Haleakala, Hawaii has become the leading discovery telescope for Near-Earth Objects (NEOs), and is now responsible for discovering almost half of all new NEOs, more than half of all larger NEOs, and more than half of all new comets. The survey routinely reaches depths of V=22 or fainter (in dark sky conditions) over an area of approximately 1,000 square degrees per night. The survey strategy will be described. The survey will soon be augmented by the addition of the Pan-STARRS2 telescope, which has similar optics and an improved camera, and which will roughly double the survey power. A sample of the important recent solar system discoveries made by the Pan-STARRS survey will be summarized.
Properties and evolution of near-Earth-object families created by tidal disruption at the Earth

NASA Astrophysics Data System (ADS)

Schunova, E.; Walsh, K.; Granvik, M.; Jedicke, R.; Wainscoat, R.; Haghighipour, N.

2014-07-01

We have calculated the coherence and detectable lifetimes of synthetic near-Earth object (NEO) families created by catastrophic disruption of a progenitor as it suffers a very close Earth approach. The closest or slowest approaches yield the most violent 'S-class' disruption events and create a 'string of pearls' configuration of the resulting fragments after their reaccummulation into gravitationally bound components [3]. We found that the average absolute magnitude (H) difference between the parent body and the largest fragment is Δ H ˜ 1.0. The average slope of the absolute magnitude (H) distribution, N(H)∝10^{(0.55±0.04) H}, for the fragments in the S-class families is steeper than the slope of the NEO population [2] in the same size range. The families remain coherent as statistically significant clusters of orbits within the NEO population for an average of barτ_c = (14.7±0.6)×10^3 years after disruption. The detectable lifetimes of tidally disrupted families are extremely short compared to the multi-Myr and -Gyr lifetimes of main belt families due to the chaotic dynamical environment in NEO space -- they are detectable with the techniques developed by [1] and [4] for an average duration (barτ_{det}) ranging from about 2,000 to about 12,000 years for progenitors in the absolute magnitude (H_p) range from 20 to 13 corresponding to diameters in the range from about 0.5 to 10 km respectively. The maximum absolute magnitude of a progenitor capable of producing an observable NEO family (i.e. detectable by our family finding technique) is H_{p,max} = 20 (about 350 m diameter). The short detectability lifetime explains why zero NEO families have been discovered to-date. Nonetheless, every tidal disruption event of a progenitor with diameter greater than 0.5 km is capable of producing several million fragments in the 1 m to 10 m diameter range that can contribute to temporary local density enhancements of small NEOs in Earth's vicinity. These objects may be suitable targets for asteroid retrieval missions due to their Earth-like orbits with corresponding low v_∞ which permits low-cost missions. The fragments from the tidal disruptions evolve into orbits that bring them into collision with terrestrial planets or the Sun or they may be ejected from the solar system on hyperbolic orbits due to deep planetary encounters. The end-state for the fragments from a tidal disruption at Earth have ˜5× the collision probability with Earth compared to the background NEO population.

Human and Robotic Exploration of Near-Earth Objects

NASA Technical Reports Server (NTRS)

Abell, Paul A.

2010-01-01

A study in late 2006 was sponsored by the Advanced Projects Office within NASA's Constellation Program to examine the feasibility of sending the Orion Crew Exploration Vehicle to a near-Earth object (NEO). The ideal mission profile would involve two or three astronauts on a 90 to 180 day flight, which would include a 7 to 14 day stay for proximity operations at the target NEO. More recently U.S. President Obama stated on April 15, 2010 that the next goal for human spaceflight will be to send human beings to a near-Earth asteroid by 2025. Given this direction from the White House, NASA has been involved in studying various strategies for NEO exploration in order to follow U.S. space exploration policy. Prior to sending a human mission, a series of robotic spacecraft would be launched to reduce the risk to crew, and enhance the planning for the proximity and surface operations at the NEO. The human mission would ideally follow five or more years later. This mission would be the first human expedition to an interplanetary body beyond the Earth-Moon system and would prove useful for testing technologies required for human missions to Mars and other solar system destinations. Piloted missions to NEOs would undoubtedly provide a great deal of technical and engineering data on spacecraft operations for future human space exploration while conducting in-depth scientific investigations of these primitive objects. The main scientific advantage of sending piloted missions to NEOs would be the flexibility of the crew to perform tasks and to adapt to situations in real time. A crewed vehicle would be able to test several different sample collection techniques and target specific areas of interest via extra-vehicular activities (EVAs) more efficiently than robotic spacecraft. Such capabilities greatly enhance the scientific return from these missions to NEOs, destinations vital to understanding the evolution and thermal histories of primitive bodies during the formation of the early solar system. Data collected from these missions would help constrain the suite of materials possibly delivered to the early Earth, and would identify potential source regions from which NEOs originate. In addition, the resulting scientific investigations would refine designs for future extraterrestrial resource extraction and utilization, and assist in the development of hazard mitigation techniques for planetary defense.
New Technologies and Strategies to Exploit Near Earth Asteroids for Breakthrough Space Development

NASA Astrophysics Data System (ADS)

Rather, John; Powell, James; Maise, George

2010-01-01

The past two decades have brought a profound expansion of knowledge of near earth objects (NEO). If creatively exploited, NEOs can significantly increase human safety while reducing costs of exploration and development of the moon, Mars and the solar system. Synergistically, the ability to defend the Earth from devastating impacts will become very effective. A spherical volume having a radius equivalent to the moon's orbit, 400,000 km, is visited every day by approximately ten NEOs having diameters of ~10 meters, while ~30 meter diameter encounters occur about once per month. Because these objects are usually very faint and only within detectable range for a few days, they require specialized equipment to discover them with high probability of detection and to enable accurate determination of orbital parameters. Survey systems are now being implemented that are cataloging many thousands of objects larger than 30 meters, but numerous advantages will result from extending the complete NEO census down to 10 meter diameters. The typical compositions of such NEOs will range from ~80% that are low density dust & rock ``rubble piles'' to perhaps 2% containing heavy metals-properties well known from meteorite samples. It is quite possible that there will also be some fragments of short period comets that are rich in water ice and other volatile components. In this paper we will propose a set of new technologies and strategies for exploiting NEO resources that can yield important space development breakthroughs at much lower costs than existing concepts. Solar powered ``Tugboats'' deployed at the space station can rendezvous with carefully selected NEOs and steer them into captured orbits in the lunar L4 & L5 regions. Robotic equipment will then modify them for a plethora of benefits. Notably, the problem of radiation shielding against the Van Allen belts, solar flares and cosmic rays will be solved. Free transportation from low earth orbit to the moon and beyond will be feasible via shielded habitats in elliptical orbits. Large, comfortable habitats for long duration trips to Mars and beyond can be built. Propulsion for orbital transfer and maneuvering of heavy payloads can be accomplished by solar energized ejection of NEO materials. Industries can be developed based upon reconditioning materials for use in space and recovery of heavy metals for use on Earth.
Distribution of the near-earth objects

NASA Astrophysics Data System (ADS)

Emel'Yanenko, V. V.; Naroenkov, S. A.; Shustov, B. M.

2011-12-01

This paper analyzes the distribution of the orbits of near-Earth minor bodies from the data on more than 7500 objects. The distribution of large near-Earth objects (NEOs) with absolute magnitudes of H < 18 is generally consistent with the earlier predictions (Bottke et al., 2002; Stuart, 2003), although we have revealed a previously undetected maximum in the distribution of perihelion distances q near q = 0.5 AU. The study of the orbital distribution for the entire sample of all detected objects has found new significant features. In particular, the distribution of perihelion longitudes seriously deviates from a homogeneous pattern; its variations are roughly 40% of its mean value. These deviations cannot be stochastic, which is confirmed by the Kolmogorov-Smirnov test with a more than 0.9999 probability. These features can be explained by the dynamic behavior of the minor bodies related to secular resonances with Jupiter. For the objects with H < 18, the variations in the perihelion longitude distribution are not so apparent. By extrapolating the orbital characteristics of the NEOs with H < 18, we have obtained longitudinal, latitudinal, and radial distributions of potentially hazardous objects in a heliocentric ecliptic coordinate frame. The differences in the orbital distributions of objects of different size appear not to be a consequence of observational selection, but could indicate different sources of the NEOs.
The search for Near Earth Objects - why dark skies are critically important

NASA Astrophysics Data System (ADS)

Wainscoat, Richard

2015-08-01

Impact of Earth by asteroids is perhaps the only natural disaster that can be prevented. If an asteroid that will impact Earth can be identified sufficiently early, it is possible to modify its orbit to eliminate the impact. As a consequence, a major effort is presently underway to identify Near Earth Objects (NEOs) that may present a threat to Earth. The impact of a 20-meter diameter object near Chelyabinsk, Russia, provided a spectacular reminder of the threat that these objects present. Although no deaths were caused, injuries and a large amount of property damage were caused.The search for NEOs is mostly funded by NASA. The principal search telescopes are the Pan-STARRS telescopes, located on Haleakala, Maui, Hawaii, and the Catalina Sky Survey, located near Tucson, Arizona. Both of these locations are seriously threatened by light pollution. A new survey, ATLAS, will commence shortly, with one telescope located on Haleakala, Maui, and the other telescope located on Mauna Loa, Hawaii (which is less threatened).Artificial light (i.e., light pollution) at these observing sites raises the sky background, and makes faint objects harder or impossible to see.Searches for Near Earth Objects typically use very broad passbands in order to obtain the maximum amount of light. These passbands typically stretch from 400 to 820 nm. As such, they are very vulnerable to the changes in lighting that are occurring across the globe, with widespread introduction of blue-rich white lighting. It is critically important in all of these locations to limit the amount of blue light that is so readily scattered by the atmosphere.A network of followup telescopes, spread across the planet, play a crucial role in the discovery of NEOs. After a new NEO is identified by the survey telescopes such as Pan-STARRS and Catalina, additional observations must be secured to establish its orbit, and in order to determine whether it poses a threat to Earth. The majority of these followup telescopes are at locations that are impacted by light pollution, and this seriously impacts their ability to secure additional observations.
Sky-plane discovery rates for Near Earth Object discoveries from Pan-STARRS1 - implications for future search strategies

NASA Astrophysics Data System (ADS)

Wainscoat, Richard J.; Chambers, Kenneth C.; Chastel, Serge; Denneau, Larry; Lilly Schunova, Eva; Micheli, Marco; Weryk, Robert J.

2016-10-01

The Pan-STARRS1 telescope has been spending most of its time for the last 2.5 years searching the sky for Near Earth Objects (NEOs). The surveyed area covers the entire northern sky and extends south to -49 degrees declination. Because Pan-STARRS1 has a large field-of-view, it has been able survey large areas of the sky, and we are now able to examine NEO discovery rates relative to ecliptic latitude.Most contemporary searches, including Pan-STARRS1, have been spending large amounts of their observing time during the dark moon period searching for NEOs close to the ecliptic. The rationale for this is that many objects have low inclination, and all objects in orbit around the Sun must cross the ecliptic. New search capabilities are now available, including Pan-STARRS2, and the upgraded camera in Catalina Sky Survey's G96 telescope. These allow NEO searches to be conducted over wider areas of the sky, and to extend further from the ecliptic.We have examined the discovery rates relative to location on the sky for new NEOs from Pan-STARRS1, and find that the new NEO discoveries are less concentrated on the ecliptic than might be expected. This finding also holds for larger objects. The southern sky has proven to be very productive in new NEO discoveries - this is a direct consequence of the major NEO surveys being located in the northern hemisphere.Our preliminary findings suggest that NEO searches should extend to at least 30 degrees from the ecliptic during the more sensitive dark moon period. At least 6,000 deg2 should therefore be searched each lunation. This is possible with the newly augmented NEO search assets, and repeat coverage will be needed in order to recover most of the NEO candidates found. However, weather challenges will likely make full and repeated coverage of such a large area of sky difficult to achieve. Some simple coordination between observing sites will likely lead to improvement in efficiency.
The Undiscovered Country: How Many Low-Delta-V Near-Earth Objects Remain to be Found?

NASA Astrophysics Data System (ADS)

Elvis, Martin; Ranjan, Sukrit; Galache, Jose Luis

2014-11-01

Low delta-v near-Earth objects (NEOs) are of great interest as targets for science and human missions, for possible retrieval to cis-lunar space and as potential resource targets for both exploration and commercial uses. This interest stems from the exponential nature of the rocket equation that imposes a harsh mass penalty on any mission to a higher delta-v. We have compared the known NEO population from the IAU Minor Planet Center (MPC) with the NEOSSat-1 model residence times for the NEO population (Greenstreet & Gladman, 2012) to assess how many undiscovered NEOs there are as a function of H magnitude and delta-v. We find that the median of known NEOs is at lower delta-v (7.3 km/s) than the model population (9.8 km/s), suggesting a bias toward detecting lower delta-v NEOs. To the precision of our data, which is as low as 40% for the 300-500 m diameter (D) objects, the bulk of the larger D>300 m NEOs have been found from delta-v<10.3 km/s. However in the 50 < D < 300 m range there are tens of thousands of delta-v < 10.3 km/s to be found. We examine the total number of undiscovered NEOs as a function of delta-v and find that to find at least 100 now unknown NEOs requires a threshold delta-v of 5.7 km/s, while to find at least 1000 of them requires a threshold delta-v of 6.2 km/s. These numbers can be used to determine mission delta-v requirements for a given number of suitable targets, that will likely be restricted by other criteria (size, composition, spin state) to a few percent of the total population.
The Mission Accessible Near-Earth Object Survey (MANOS) -- Science Highlights

NASA Astrophysics Data System (ADS)

Moskovitz, Nicholas; Thirouin, Audrey; Binzel, Richard; Burt, Brian; Christensen, Eric; DeMeo, Francesca; Endicott, Thomas; Hinkle, Mary; Mommert, Michael; Person, Michael; Polishook, David; Siu, Hosea; Thomas, Cristina; Trilling, David; Willman, Mark

2015-08-01

Near-Earth objects (NEOs) are essential to understanding the origin of the Solar System through their compositional links to meteorites. As tracers of other parts of the Solar System they provide insight to more distant populations. Their small sizes and complex dynamical histories make them ideal laboratories for studying ongoing processes of planetary evolution. Knowledge of their physical properties is essential to impact hazard assessment. And the proximity of NEOs to Earth make them favorable targets for a variety of planetary mission scenarios. However, in spite of their importance, only the largest NEOs are well studied and a representative sample of physical properties for sub-km NEOs does not exist.MANOS is a multi-year physical characterization survey, originally awarded survey status by NOAO. MANOS is targeting several hundred mission-accessible, sub-km NEOs across visible and near-infrared wavelengths to provide a comprehensive catalog of physical properties (astrometry, light curves, spectra). Accessing these targets is enabled through classical, queue, and target-of-opportunity observations carried out at 1- to 8-meter class facilities in the northern and southern hemispheres. Our observing strategy is designed to rapidly characterize newly discovered NEOs before they fade beyond observational limits.Early progress from MANOS includes: (1) the de-biased taxonomic distribution of spectral types for NEOs smaller than ~100 meters, (2) the distribution of rotational properties for approximately 100 previously unstudied NEOs, (3) detection of the fastest known rotation period of any minor planet in the Solar System, (4) an investigation of the influence of planetary encounters on the rotational properties of NEOs, (5) dynamical models for the evolution of the overall NEO population over the past 0.5 Myr, and (6) development of a new set of online tools at asteroid.lowell.edu that will enable near realtime public dissemination of our data products while providing a portal to facilitate observation planning and coordination within the small body observer community. We will present highlights of these early MANOS science results.
A resonant family of dynamically cold small bodies in the near-Earth asteroid belt

NASA Astrophysics Data System (ADS)

de la Fuente Marcos, C.; de la Fuente Marcos, R.

2013-07-01

Near-Earth objects (NEOs) moving in resonant, Earth-like orbits are potentially important. On the positive side, they are the ideal targets for robotic and human low-cost sample return missions and a much cheaper alternative to using the Moon as an astronomical observatory. On the negative side and even if small in size (2-50 m), they have an enhanced probability of colliding with the Earth causing local but still significant property damage and loss of life. Here, we show that the recently discovered asteroid 2013 BS45 is an Earth co-orbital, the sixth horseshoe librator to our planet. In contrast with other Earth's co-orbitals, its orbit is strikingly similar to that of the Earth yet at an absolute magnitude of 25.8, an artificial origin seems implausible. The study of the dynamics of 2013 BS45 coupled with the analysis of NEO data show that it is one of the largest and most stable members of a previously undiscussed dynamically cold group of small NEOs experiencing repeated trappings in the 1:1 commensurability with the Earth. This new resonant family is well constrained in orbital parameter space and it includes at least 10 other transient members: 2003 YN107, 2006 JY26, 2009 SH2 and 2012 FC71 among them. 2012 FC71 represents the best of both worlds as it is locked in a Kozai resonance and is unlikely to impact the Earth. These objects are not primordial and may have originated within the Venus-Earth-Mars region or in the main-belt, then transition to Amor-class asteroid before entering Earth's co-orbital region. Objects in this group could be responsible for the production of Earth's transient irregular natural satellites.
NEOview: Near Earth Object Data Discovery and Query

NASA Astrophysics Data System (ADS)

Tibbetts, M.; Elvis, M.; Galache, J. L.; Harbo, P.; McDowell, J. C.; Rudenko, M.; Van Stone, D.; Zografou, P.

2013-10-01

Missions to Near Earth Objects (NEOs) figure prominently in NASA's Flexible Path approach to human space exploration. NEOs offer insight into both the origins of the Solar System and of life, as well as a source of materials for future missions. With NEOview scientists can locate NEO datasets, explore metadata provided by the archives, and query or combine disparate NEO datasets in the search for NEO candidates for exploration. NEOview is a software system that illustrates how standards-based interfaces facilitate NEO data discovery and research. NEOview software follows a client-server architecture. The server is a configurable implementation of the International Virtual Observatory Alliance (IVOA) Table Access Protocol (TAP), a general interface for tabular data access, that can be deployed as a front end to existing NEO datasets. The TAP client, seleste, is a graphical interface that provides intuitive means of discovering NEO providers, exploring dataset metadata to identify fields of interest, and constructing queries to retrieve or combine data. It features a powerful, graphical query builder capable of easing the user's introduction to table searches. Through science use cases, NEOview demonstrates how potential targets for NEO rendezvous could be identified by combining data from complementary sources. Through deployment and operations, it has been shown that the software components are data independent and configurable to many different data servers. As such, NEOview's TAP server and seleste TAP client can be used to create a seamless environment for data discovery and exploration for tabular data in any astronomical archive.
The Mission Accessible Near-Earth Object Survey (MANOS)

NASA Astrophysics Data System (ADS)

Moskovitz, N.; Manos Team

2014-07-01

Near-Earth objects (NEOs) are essential to understanding the origin of the Solar System through their compositional links to meteorites. As tracers of various regions within the Solar System they can provide insight to more distant, less accessible populations. Their relatively small sizes and complex dynamical histories make them excellent laboratories for studying ongoing Solar System processes such as space weathering, planetary encounters, and non-gravitational dynamics. Knowledge of their physical properties is essential to impact hazard assessment. Finally, the proximity of NEOs to Earth make them favorable targets for robotic and human exploration. However, in spite of their scientific importance, only the largest (km-scale) NEOs have been well studied and a representative sample of physical characteristics for sub-km NEOs does not exist. To address these issues we are conducting the Mission Accessible Near-Earth Object Survey (MANOS), a fully allocated multi-year survey of sub-km NEOs that will provide a large, uniform catalog of physical properties including light curves, spectra, and astrometry. From this comprehensive catalog, we will derive global properties of the NEO population, as well as identify individual targets that are of potential interest for exploration. We will accomplish these goals for approximately 500 mission-accessible NEOs across the visible and near-infrared ranges using telescope assets in both the northern and southern hemispheres. MANOS has been awarded large survey status by NOAO to employ Gemini-N, Gemini-S, SOAR, the Kitt Peak 4 m, and the CTIO 1.3 m. Access to additional facilities at Lowell Observatory (DCT 4.3 m, Perkins 72'', Hall 42'', LONEOS), the University of Hawaii, and the Catalina Sky Survey provide essential complements to this suite of telescopes. Targets for MANOS are selected based on three primary criteria: mission accessibility (i.e. Δ v < 7 km/s), size (H > 20), and observability. Our telescope assets allow us to obtain rotational light curves for objects down to V˜22, visible spectra down to V˜21, and near-IR spectra down to V˜19. MANOS primarily focuses on targets that are recently discovered. We employ a regular cadence of remote and queue observations to enable follow-up characterization within days or weeks after a target of interest is discovered. We will present a MANOS status report with an emphasis on noteworthy observations and ongoing efforts to achieve fully transparency by making target lists and data products publicly available online.
Options and uncertainties in planetary defense: Mission planning and vehicle design for flexible response

NASA Astrophysics Data System (ADS)

Barbee, Brent W.; Syal, Megan Bruck; Dearborn, David; Gisler, Galen; Greenaugh, Kevin; Howley, Kirsten M.; Leung, Ron; Lyzhoft, Josh; Miller, Paul L.; Nuth, Joseph A.; Plesko, Catherine; Seery, Bernard D.; Wasem, Joseph; Weaver, Robert P.; Zebenay, Melak

2018-02-01

This paper is part of an integrated study by NASA and the NNSA to quantitatively understand the response timeframe should a threatening Earth-impacting near-Earth object (NEO) be identified. The two realistic responses considered are the use of a spacecraft functioning as either a kinetic impactor or a nuclear explosive carrier to deflect the approaching NEO. The choice depends on the NEO size and mass, the available response time prior to Earth impact, and the various uncertainties. Whenever practical, the kinetic impactor is the preferred approach, but various factors, such as large uncertainties or short available response time, reduce the kinetic impactor's suitability and, ultimately, eliminate its sufficiency. Herein we examine response time and the activities that occur between the time when an NEO is recognized as being a sufficient threat to require a deflection and the time when the deflection impulse is applied to the NEO. To use a kinetic impactor for successful deflection of an NEO, it is essential to minimize the reaction time and maximize the time available for the impulse delivered to the NEO by the kinetic impactor to integrate forward in time to the eventual deflection of the NEO away from Earth impact. To shorten the response time, we develop tools to survey the profile of needed spacecraft launches and the possible mission payloads. We further present a vehicle design capable of either serving as a kinetic impactor, or, if the need arises, serving as a system to transport a nuclear explosive to the NEO. These results are generated by analyzing a specific case study in which the simulated Earth-impacting NEO is modeled very closely after the real NEO known as 101955 Bennu (1999 RQ36). Bennu was selected for our case study in part because it is the best-studied of the known NEOs. It is also the destination of NASA's OSIRIS-REx sample return mission, which is, at the time of this writing, enroute to Bennu following a September 2016 launch.
The Mission Accessible Near-Earth Object Survey (MANOS): Project Overview

NASA Astrophysics Data System (ADS)

Moskovitz, Nicholas; Polishook, David; Thomas, Cristina; Willman, Mark; DeMeo, Francesca; Mommert, Michael; Endicott, Thomas; Trilling, David; Binzel, Richard; Hinkle, Mary; Siu, Hosea; Neugent, Kathryn; Christensen, Eric; Person, Michael; Burt, Brian; Grundy, Will; Roe, Henry; Abell, Paul; Busch, Michael

2014-11-01

The Mission Accessible Near-Earth Object Survey (MANOS) began in August 2013 as a multi-year physical characterization survey that was awarded survey status by NOAO. MANOS will target several hundred mission-accessible NEOs across visible and near-infrared wavelengths, ultimately providing a comprehensive catalog of physical properties (astrometry, light curves, spectra). Particular focus is paid to sub-km NEOs, for which little data currently exists. These small bodies are essential to understanding the link between meteorites and asteroids, pose the most immediate impact hazard to the Earth, and are highly relevant to a variety of planetary mission scenarios. Accessing these targets is enabled through a combination of classical, queue, and target-of-opportunity observations carried out at 1- to 8-meter class facilities in both the northern and southern hemispheres. The MANOS observing strategy is specifically designed to rapidly characterize newly discovered NEOs before they fade beyond observational limits. MANOS will provide major advances in our understanding of the NEO population as a whole and for specific objects of interest. Here we present an overview of the survey, progress to date, and early science highlights including: (1) an estimate of the taxonomic distribution of spectral types for NEOs smaller than ~100 meters, (2) the distribution of rotational properties for approximately 100 previously unstudied objects, (3) models for the dynamical evolution of the overall NEO population over the past 0.5 Myr, and (4) progress in developing a new set of online tools at asteroid.lowell.edu that will enable near realtime public dissemination of our data while providing a portal to facilitate coordination efforts within the small body observer community.MANOS is supported through telescope allocations from NOAO and Lowell Observatory. We acknowledge funding support from an NSF Astronomy and Astrophysics Postdoctoral Fellowship to N. Moskovitz and NASA NEOO grant number NNX14AN82G (PI N. Moskovitz).
Properties and evolution of NEO families created by tidal disruption at Earth

NASA Astrophysics Data System (ADS)

Schunová, Eva; Jedicke, Robert; Walsh, Kevin J.; Granvik, Mikael; Wainscoat, Richard J.; Haghighipour, Nader

2014-08-01

We have calculated the coherence and detectable lifetimes of synthetic near-Earth object (NEO) families created by catastrophic disruption of a progenitor as it suffers a very close Earth approach. The closest or slowest approaches yield the most violent ‘s-class’ disruption events where the largest remaining fragment after disruption and reaccumulation retains less than 50% of the parent’s mass. The resulting fragments have a ‘string of pearls’ configuration after their reaccummulation into gravitationally bound components (Richardson, D.C., Bottke, W.F., Love, S.G. [1998]. Icarus 134, 47-76). We found that the average absolute magnitude (H) difference between the parent body and the largest fragment is ΔH∼1.0. The average slope of the absolute magnitude (H) distribution, N(H)∝10, for the fragments in the s-class families is steeper than the slope of the NEO population (Mainzer, A., et al. [2011]. Astrophys. J. 743, 156) in the same size range. The es remain coherent as statistically significant clusters of orbits within the NEO population for an average of τbarc=(14.7±0.6)×103 yr after disruption. The detectable lifetimes of tidally disrupted families are extremely short compared to the multi-Myr and -Gyr lifetimes of main belt families due to the chaotic dynamical environment in NEO space-they are detectable with the techniques developed by Fu et al. and Schunová et al. (Fu, H., Jedicke, R., Durda, D.D., Fevig, R., Binzel, R.P. [2005]. Icarus 178(2), 434-449 and Schunová, E., Granvik, M., Jedicke, R., Gronchi, G., Wainscoat, R., Abe, S. [2012]. Icarus 220, 1050-1063) for an average duration (τbardet) ranging from about 2000 to about 12,000 years for progenitors in the absolute magnitude (Hp) range from 20 to 13 corresponding to diameters in the range from about 0.5 to 10 km respectively. The maximum absolute magnitude of a progenitor capable of producing an observable NEO family (i.e. detectable by our family finding technique) is Hp,max=20 (about 350 m diameter). The short detectability lifetime explains why zero NEO families have been discovered to-date. Nonetheless, every tidal disruption event of a progenitor with diameter greater than 0.5 km is capable of producing several million fragments in the 1-10 m diameter range that can contribute to temporary local density enhancements of small NEOs in Earth’s vicinity. We expect that there are about 1200 objects in the steady state NEO population in this size range due to tidal disruption assuming that one 1 km diameter NEO tidally disrupts at Earth every 2500 years. These objects may be suitable targets for asteroid retrieval missions due to their Earth-like orbits with corresponding low v∞ which permits low-cost missions. The fragments from the tidal disruptions evolve into orbits that bring them into collision with terrestrial planets or the Sun or they may be ejected from the Solar System on hyperbolic orbits due to deep planetary encounters. The end-state for the fragments from a tidal disruption at Earth have ∼5× the collision probability with Earth compared to the background NEO population.
Dynamical evolution of near-Earth asteroid 1991 VG

NASA Astrophysics Data System (ADS)

de la Fuente Marcos, C.; de la Fuente Marcos, R.

2018-01-01

The discovery of 1991 VG on 1991 November 6 attracted an unprecedented amount of attention as it was the first near-Earth object (NEO) ever found on an Earth-like orbit. At that time, it was considered by some as the first representative of a new dynamical class of asteroids, while others argued that an artificial (terrestrial or extraterrestrial) origin was more likely. Over a quarter of a century later, this peculiar NEO has been recently recovered and the new data may help in confirming or ruling out early theories about its origin. Here, we use the latest data to perform an independent assessment of its current dynamical status and short-term orbital evolution. Extensive N-body simulations show that its orbit is chaotic on time-scales longer than a few decades. We confirm that 1991 VG was briefly captured by Earth's gravity as a minimoon during its previous fly-by in 1991-1992; although it has been a recurrent transient co-orbital of the horseshoe type in the past and it will return as such in the future, it is not a present-day co-orbital companion of the Earth. A realistic NEO orbital model predicts that objects like 1991 VG must exist and, consistently, we have found three other NEOs - 2001 GP2, 2008 UA202 and 2014 WA366 - which are dynamically similar to 1991 VG. All this evidence confirms that there is no compelling reason to believe that 1991 VG is not natural.
Conceptual Design of a Flight Validation Mission for a Hypervelocity Asteroid Intercept Vehicle

NASA Technical Reports Server (NTRS)

Barbee, Brent W.; Wie, Bong; Steiner, Mark; Getzandanner, Kenneth

2013-01-01

Near-Earth Objects (NEOs) are asteroids and comets whose orbits approach or cross Earth s orbit. NEOs have collided with our planet in the past, sometimes to devastating effect, and continue to do so today. Collisions with NEOs large enough to do significant damage to the ground are fortunately infrequent, but such events can occur at any time and we therefore need to develop and validate the techniques and technologies necessary to prevent the Earth impact of an incoming NEO. In this paper we provide background on the hazard posed to Earth by NEOs and present the results of a recent study performed by the NASA/Goddard Space Flight Center s Mission Design Lab (MDL) in collaboration with Iowa State University s Asteroid Deflection Research Center (ADRC) to design a flight validation mission for a Hypervelocity Asteroid Intercept Vehicle (HAIV) as part of a Phase 2 NASA Innovative Advanced Concepts (NIAC) research project. The HAIV is a two-body vehicle consisting of a leading kinetic impactor and trailing follower carrying a Nuclear Explosive Device (NED) payload. The HAIV detonates the NED inside the crater in the NEO s surface created by the lead kinetic impactor portion of the vehicle, effecting a powerful subsurface detonation to disrupt the NEO. For the flight validation mission, only a simple mass proxy for the NED is carried in the HAIV. Ongoing and future research topics are discussed following the presentation of the detailed flight validation mission design results produced in the MDL.
Towards Designing an Integrated Architecture for NEO Characterization, Mitigation, Scientific Evaluation, and Resource Utilization

NASA Technical Reports Server (NTRS)

Adams, Robert B.; LaPointe, Michael; Wilks, Rod; Allen, Brian

2009-01-01

This poster reviews the planning and design for an integrated architecture for characterization, mitigation, scientific evaluation and resource utilization of near earth objects. This includes tracks to observe and characterize the nature of the threat posed by a NEO, and deflect if a significant threat is posed. The observation stack can also be used for a more complete scientific analysis of the NEO.
Near Earth Objects - a threat and an opportunity

NASA Astrophysics Data System (ADS)

Tate, Jonathan R.

2003-05-01

In the past decade the hazard posed to the Earth by Near Earth Objects (NEOs) has generated considerable scientific and public interest. A number of major films, television programmes and media reports have brought the issue to public attention. From an educational perspective an investigation into NEOs and the effects of impacts on the Earth forms a topical and dynamic basis for study in a huge range of subjects, not just scientific. There are clear routes to chemistry, physics, mathematics and biology, but history, psychology, geography, palaeontology and geology are just a selection of other subjects involved. A number of projects have been established, mainly in the USA, to determine the extent of the hazard, and to develop ways of countering it, but the present situation is far from satisfactory. Current detection and follow-up programmes are underfunded and lack international coordination.
Synergistic Activities of Near-Earth Object Exploration

NASA Technical Reports Server (NTRS)

Abell, Paul

2011-01-01

U.S. President Obama stated on April 15, 2010 that the next goal for human spaceflight will be to send human beings to near-Earth asteroids by 2025. Missions to NEOs would undoubtedly provide a great deal of technical and engineering data on spacecraft operations for future human space exploration while conducting in-depth scientific examinations of these primitive objects. Information obtained from a human investigation of a NEO, together with ground-based observations and prior spacecraft investigations of asteroids and comets, will also provide a real measure of ground truth to data obtained from terrestrial meteorite collections. Major advances in the areas of geochemistry, impact history, thermal history, isotope analyses, mineralogy, space weathering, formation ages, thermal inertias, volatile content, source regions, solar system formation, etc. can be expected from human NEO missions. Samples directly returned from a primitive body would lead to the same kind of breakthroughs for understanding NEOs that the Apollo samples provided for understanding the Earth-Moon system and its formation history. In addition, robotic precursor and human exploration missions to NEOs would allow the NASA and its international partners to gain operational experience in performing complex tasks (e.g., sample collection, deployment of payloads, retrieval of payloads, etc.) with crew, robots, and spacecraft under microgravity conditions at or near the surface of a small body. This would provide an important synergy between the worldwide Science and Exploration communities, which will be crucial for development of future international deep space exploration architectures and has potential benefits for future exploration of other destinations beyond low-Earth orbit.
The LCOGT NEO Follow-up Network

NASA Astrophysics Data System (ADS)

Lister, Tim; Gomez, Edward; Greenstreet, Sarah

2015-08-01

Las Cumbres Observatory Global Telescope Network (LCOGT) has deployed a homogeneous telescope network of nine 1-meter telescopes to four locations in the northern and southern hemispheres, with a planned network of twelve 1-meter telescopes at 6 locations. This network is very versatile and is designed to respond rapidly to target of opportunity events and also to perform long term monitoring of slowly changing astronomical phenomena. The global coverage of the network and the apertures of telescope available make LCOGT ideal for follow-up and characterization of Solar System objects (e.g. asteroids, Kuiper Belt Objects, comets, Near-Earth Objects (NEOs)) and ultimately for the discovery of new objects.LCOGT has completed the first phase of the deployment with the installation and commissioning of the nine 1-meter telescopes at McDonald Observatory (Texas), Cerro Tololo (Chile), SAAO (South Africa) and Siding Spring Observatory (Australia). The telescope network has been fully operational since 2014 May, and observations are being executed remotely and robotically. Future expansion to sites in the Canary Islands and Tibet is planned for 2016.I am using the LCOGT network to confirm newly detected NEO candidates produced by the major sky surveys such as Catalina Sky Survey (CSS) and PanSTARRS (PS1) and several hundred targets are now being followed-up per year. An increasing amount of time is being spent to obtain follow-up astrometry and photometry for radar-targeted objects and those on the Near-Earth Object Human Space Flight Accessible Targets Study (NHATS) or Asteroid Retrieval Mission (ARM) lists in order to improve the orbits, determine the light curves and rotation periods and improve the characterization. This will be extended to obtain more light curves of other NEOs which could be targets. Recent results have included the first period determinations for several of the Goldstone-targeted NEOs. We are in the process of building a NEO Portal which will allow professionals, amateurs and Citizen Scientists to plan, schedule and analyze NEO imaging and spectroscopy observations and data using the LCOGT Network and to act as a co-ordination hub for the NEO follow-up efforts.
Astronomical Research Institute Photometric Results

NASA Astrophysics Data System (ADS)

Linder, Tyler R.; Sampson, Ryan; Holmes, Robert

2013-01-01

The Astronomical Research Institute (ARI) conducts astrometric and photometric studies of asteroids with a concentration on near-Earth objects (NEOs). A 0.76-m autoscope was used for photometric studies of seven asteroids of which two were main-belt targets and five were NEOs, including one potentially hazardous asteroid (PHA). These objects are: 3122 Florence, 3960 Chaliubieju, 5143 Heracles, (6455) 1992 HE, (36284) 2000 DM8, (62128) 2000 SO1, and 2010 LF86.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mainzer, A.; Bauer, J.; Masiero, J.

NASA's Wide-field Infrared Survey Explorer (WISE) spacecraft has been brought out of hibernation and has resumed surveying the sky at 3.4 and 4.6 μm. The scientific objectives of the NEOWISE reactivation mission are to detect, track, and characterize near-Earth asteroids and comets. The search for minor planets resumed on 2013 December 23, and the first new near-Earth object (NEO) was discovered 6 days later. As an infrared survey, NEOWISE detects asteroids based on their thermal emission and is equally sensitive to high and low albedo objects; consequently, NEOWISE-discovered NEOs tend to be large and dark. Over the course of itsmore » three-year mission, NEOWISE will determine radiometrically derived diameters and albedos for ∼2000 NEOs and tens of thousands of Main Belt asteroids. The 32 months of hibernation have had no significant effect on the mission's performance. Image quality, sensitivity, photometric and astrometric accuracy, completeness, and the rate of minor planet detections are all essentially unchanged from the prime mission's post-cryogenic phase.« less
Search for Near-Earth Objects with Small Aphelion Distances

NASA Technical Reports Server (NTRS)

Tholen, David J.

2004-01-01

Progress for the period 13 July 2003 through 11 August 2004 is reported. Report topics include personnel, NEO follow-up astrometry, and the continued search for near-Earth asteroids with small aphelion distances.
The Large Synoptic Survey Telescope as a Near-Earth Object discovery machine

NASA Astrophysics Data System (ADS)

Jones, R. Lynne; Slater, Colin T.; Moeyens, Joachim; Allen, Lori; Axelrod, Tim; Cook, Kem; Ivezić, Željko; Jurić, Mario; Myers, Jonathan; Petry, Catherine E.

2018-03-01

Using the most recent prototypes, design, and as-built system information, we test and quantify the capability of the Large Synoptic Survey Telescope (LSST) to discover Potentially Hazardous Asteroids (PHAs) and Near-Earth Objects (NEOs). We empirically estimate an expected upper limit to the false detection rate in LSST image differencing, using measurements on DECam data and prototype LSST software and find it to be about 450 deg-2. We show that this rate is already tractable with current prototype of the LSST Moving Object Processing System (MOPS) by processing a 30-day simulation consistent with measured false detection rates. We proceed to evaluate the performance of the LSST baseline survey strategy for PHAs and NEOs using a high-fidelity simulated survey pointing history. We find that LSST alone, using its baseline survey strategy, will detect 66% of the PHA and 61% of the NEO population objects brighter than H = 22 , with the uncertainty in the estimate of ± 5 percentage points. By generating and examining variations on the baseline survey strategy, we show it is possible to further improve the discovery yields. In particular, we find that extending the LSST survey by two additional years and doubling the MOPS search window increases the completeness for PHAs to 86% (including those discovered by contemporaneous surveys) without jeopardizing other LSST science goals (77% for NEOs). This equates to reducing the undiscovered population of PHAs by additional 26% (15% for NEOs), relative to the baseline survey.
Preparing for LSST with the LCOGT NEO Follow-up Network

NASA Astrophysics Data System (ADS)

Greenstreet, Sarah; Lister, Tim; Gomez, Edward

2016-10-01

The Las Cumbres Observatory Global Telescope Network (LCOGT) provides an ideal platform for follow-up and characterization of Solar System objects (e.g. asteroids, Kuiper Belt Objects, comets, Near-Earth Objects (NEOs)) and ultimately for the discovery of new objects. The LCOGT NEO Follow-up Network is using the LCOGT telescope network in addition to a web-based system developed to perform prioritized target selection, scheduling, and data reduction to confirm NEO candidates and characterize radar-targeted known NEOs.In order to determine how to maximize our NEO follow-up efforts, we must first define our goals for the LCOGT NEO Follow-up Network. This means answering the following questions. Should we follow-up all objects brighter than some magnitude limit? Should we only focus on the brightest objects or push to the limits of our capabilities by observing the faintest objects we think we can see and risk not finding the objects in our data? Do we (and how do we) prioritize objects somewhere in the middle of our observable magnitude range? If we want to push to faint objects, how do we minimize the amount of data in which the signal-to-noise ratio is too low to see the object? And how do we find a balance between performing follow-up and characterization observations?To help answer these questions, we have developed a LCOGT NEO Follow-up Network simulator that allows us to test our prioritization algorithms for target selection, confirm signal-to-noise predictions, and determine ideal block lengths and exposure times for observing NEO candidates. We will present our results from the simulator and progress on our NEO follow-up efforts.In the era of LSST, developing/utilizing infrastructure, such as the LCOGT NEO Follow-up Network and our web-based platform for selecting, scheduling, and reducing NEO observations, capable of handling the large number of detections expected to be produced on a daily basis by LSST will be critical to follow-up efforts. We hope our work can act as an example and tool for the community as together we prepare for the age of LSST.
DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, Alan W.; Drube, Line, E-mail: alan.harris@dlr.de

The metal content of asteroids is of great interest, not only for theories of their origins and the evolution of the solar system but, in the case of near-Earth objects (NEOs), also for impact mitigation planning and endeavors in the field of planetary resources. However, since the reflection spectra of metallic asteroids are largely featureless, it is difficult to identify them and relatively few are known. We show how data from the Wide-field Infrared Survey Explorer (WISE)/NEOWISE thermal-infrared survey and similar surveys, fitted with a simple thermal model, can reveal objects likely to be metal rich. We provide a listmore » of candidate metal-rich NEOs. Our results imply that future infrared surveys with the appropriate instrumentation could discover many more metal-rich asteroids, providing valuable data for assessment of the impact hazard and the potential of NEOs as reservoirs of vital materials for future interplanetary space activities and, eventually perhaps, for use on Earth.« less
Dangerous Near-Earth Asteroids and Meteorites

NASA Astrophysics Data System (ADS)

Mickaelian, A. M.; Grigoryan, A. E.

2015-07-01

The problem of Near-Earth Objects (NEOs; Astreoids and Meteorites) is discussed. To have an understanding on the probablity of encounters with such objects, one may use two different approaches: 1) historical, based on the statistics of existing large meteorite craters on the Earth, estimation of the source meteorites size and the age of these craters to derive the frequency of encounters with a given size of meteorites and 2) astronomical, based on the study and cataloging of all medium-size and large bodies in the Earth's neighbourhood and their orbits to estimate the probability, angles and other parameters of encounters. Therefore, we discuss both aspects and give our present knowledge on both phenomena. Though dangerous NEOs are one of the main source for cosmic catastrophes, we also focus on other possible dangers, such as even slight changes of Solar irradiance or Earth's orbit, change of Moon's impact on Earth, Solar flares or other manifestations of Solar activity, transit of comets (with impact on Earth's atmosphere), global climate change, dilution of Earth's atmosphere, damage of ozone layer, explosion of nearby Supernovae, and even an attack by extraterrestrial intelligence.
Magnetospheric Effects as a New Aspect of the Asteroid Impact Problem: Necessity and Possibilities of Laboratory Simulation Experiments

NASA Astrophysics Data System (ADS)

Zakharov, Yuri P.; Nikitin, Sergei A.; Ponomarenko, Arnold G.; Minami, Shigeyuki

1997-05-01

This paper discusses the possible consequences to the Earth's magnetosphere, when due to too short an advanced warning, attempts at mitigation of a near-Earth object (NEO) must be made in close proximity to the Earth. The energy Eo, and explosive plasma release during impact may be compared with the kinetic energy Ek of the NEO and with the energy, Ee (Ee approximately Ek), needed for NEO deflection by a strong (protective force) explosive, at distances close to the scale of the magnetosphere. If the energy, Em, of the Earth's dipole field latter is relatively small (Em is less than Eo for a NEO size approximately 1 km), global or even catastrophic disturbances could occur. These ecologically important magnetospheric aspects of the NEO impact problem have been discussed recently; particularly in the context of the comet SL-9/Jupiter impact. In the latter case, the effect on Jupiter's magnetosphere of the 'NEO' explosions was very small (x equals Eo/Em approximately 0.001, where Em is the 'outer' magnetic energy of the planetary dipole field) and the corresponding model of its 'fireball' development could be simulated numerically in 'zero' approximation, with the assumption of an undisturbed magnetospheric media as a whole. However, in general, and, in the rather probable case of NEO impacts with values x approximately 1, the development of such 3D, nonstationary MHD or PIC-models at this time. Such information can be obtained from new kinds of simulation experiments with the laboratory magnetosphere, the so-called 'terrella'.
Asteroid Impact Risk: Ground Hazard versus Impactor Size

NASA Technical Reports Server (NTRS)

Mathias, Donovan; Wheeler, Lorien; Dotson, Jessie; Aftosmis, Michael; Tarano, Ana

2017-01-01

We utilized a probabilistic asteroid impact risk (PAIR) model to stochastically assess the impact risk due to an ensemble population of Near-Earth Objects (NEOs). Concretely, we present the variation of risk with impactor size. Results suggest that large impactors dominate the average risk, even when only considering the subset of undiscovered NEOs.
Near Earth Object (NEO) Mitigation Options Using Exploration Technologies

NASA Technical Reports Server (NTRS)

Adams, Robert B.

2008-01-01

This presentation considers the use of new launch vehicles in defense against near-Earth objects, building upon expertise in launch vehicle and spacecraft design, astronomy and planetary science and missile defense. This work also seeks to demonstrate the synergy needed between architectures for human/robotic exploration initiatives and planetary defense. Three different mitigation operations were baselined for this study--nuclear standoff explosion, kinetic interceptor, and solar collector--however, these are not the only viable options. The design and predicted performance of each of these methods is discussed and compared. It is determined that the nuclear interceptor option can deflect NEOs of smaller size (100-500 m) with 2 years or more time before impact, and larger NEOs with 5 or more years warning; kinetic interceptors may be effective for deflection of asteroids up to 300-400 m but require 8-10 years warning time; and, solar collectors may be able to deflect NEOs up to 1 km if issues pertaining to long operation can be overcome. Ares I and Ares V vehicles show sufficient performance to enable the development of a near-term categorization and mitigation architecture.
Characterization of the Interior Density Structure of Near Earth Objects with Muons

NASA Astrophysics Data System (ADS)

Prettyman, T. H.; Sykes, M. V.; Miller, R. S.; Pinsky, L. S.; Empl, A.; Nolan, M. C.; Koontz, S. L.; Lawrence, D. J.; Mittlefehldt, D. W.; Reddell, B. D.

2015-12-01

Near Earth Objects (NEOs) are a diverse population of short-lived asteroids originating from the main belt and Jupiter family comets. Some have orbits that are easy to access from Earth, making them attractive as targets for science and exploration as well as a potential resource. Some pose a potential impact threat. NEOs have undergone extensive collisional processing, fragmenting and re-accreting to form rubble piles, which may be compositionally heterogeneous (e.g., like 2008 TC3, the precursor to Almahata Sitta). At present, little is known about their interior structure or how these objects are held together. The wide range of inferred NEO macroporosities hint at complex interiors. Information about their density structure would aid in understanding their formation and collisional histories, the risks they pose to human interactions with their surfaces, the constraints on industrial processing of NEO resources, and the selection of hazard mitigation strategies (e.g., kinetic impactor vs nuclear burst). Several methods have been proposed to characterize asteroid interiors, including radar imaging, seismic tomography, and muon imaging (muon radiography and tomography). Of these, only muon imaging has the potential to determine interior density structure, including the relative density of constituent fragments. Muons are produced by galactic cosmic ray showers within the top meter of asteroid surfaces. High-energy muons can traverse large distances through rock with little deflection. Muons transmitted through an Itokawa-sized asteroid can be imaged using a compact hodoscope placed on or near the surface. Challenges include background rejection and correction for variations in muon production with surface density. The former is being addressed by hodoscope design. Surface density variations can be determined via radar or muon limb imaging. The performance of muon imaging is evaluated for prospective NEO interior-mapping missions.
A concept for providing warning of earth impacts by small asteroids

NASA Astrophysics Data System (ADS)

Dunham, D. W.; Reitsema, H. J.; Lu, E.; Arentz, R.; Linfield, R.; Chapman, C.; Farquhar, R.; Ledkov, A. A.; Eismont, N. A.; Chumachenko, E.

2013-07-01

The atmospheric detonation of a 17 m-asteroid above Chelyabinsk, Russia on 2013 February 15 shows that even small asteroids can cause extensive damage. Earth-based telescopes have found smaller harmless objects, such as 2008 TC3, a 4 m-asteroid that was discovered 20h before it exploded over northeastern Sudan (Jenniskens, 2009). 2008 TC3 remains the only asteroid discovered before it hit Earth because it approached Earth from the night side, where it was observed by large telescopes searching for near-Earth objects (NEO's). The larger object that exploded over Chelyabinsk approached Earth from the day side, from too close to the Sun to be detected from Earth. A sizeable telescope in an orbit about the Sun-Earth L1 (SE-L1) libration point could find objects like the "Chelyabinsk" asteroid approaching approximately from the line of sight to the Sun about a day before Earth closest approach. Such a system would have the astrometric accuracy needed to determine the time and impact zone for a NEO on a collision course. This would give at least several hours, and usually 2-4 days, to take protective measures, rather than the approximately two-minute interval between the flash and shock wave arrival that occurred in Chelyabinsk. A perhaps even more important reason for providing warning of these events, even smaller harmless ones that explode high in the atmosphere with the force of an atomic bomb, is to prevent mistaking such an event for a nuclear attack that could trigger a devastating nuclear war. A concept using a space telescope similar to that needed for an SE-L1 monitoring satellite, is already conceived by the B612 Foundation, whose planned Sentinel Space Telescope could find nearly all 140 m and larger NEO's, including those in orbits mostly inside the Earth's orbit that are hard to find with Earth-based telescopes, from a Venus-like orbit (Lu, 2013). Few modifications would be needed to the Sentinel Space Telescope to operate in a SE-L1 orbit, 0.01 AU from Earth towards the Sun, to find most asteroids larger than about 5 meters that approach the Earth from the solar direction. The spacecraft would scan 165 square degrees of the sky around the Earth every hour, finding asteroids when they are brightest (small phase angle) as they approach Earth. We will undertake Monte Carlo studies to see what fraction of asteroids 5 m and larger approaching from the Sun might be found by such a mission, and how much warning time might typically be expected. Also, we will check the overall coverage for all Earth-approaching NEO's, including ground-based observations and observations by the recently-launched NEOSSat, which may best fill any gaps in coverage between that provided by an SE-L1 telescope and ground-based surveys. Many of the objects as large as 50 m, like the one that created Meteor Crater in Arizona, will not be found by current NEO surveys, while they would usually be seen by this possible mission even if they approached from the direction of the Sun. We should give better warning for future "Bolts out of the blue."
Follow-up and Characterization of NEOs with the LCOGT Network

NASA Astrophysics Data System (ADS)

Lister, Tim

2013-10-01

Las Cumbres Observatory Global Telescope (LCOGT) network is a planned homogeneous network of over 35 telescopes at 6 locations in the northern and southern hemispheres. This network is versatile and designed to respond rapidly to target of opportunity events and also to do long term monitoring of slowly changing astronomical phenomena. The global coverage of the network and the apertures of telescope available make LCOGT ideal for follow-up and characterization of Solar System objects (e.g. asteroids, Kuiper Belt Objects, comets, Near-Earth Objects (NEOs)) and ultimately for the discovery of new objects. LCOGT has completed the first phase of the deployment with the installation and commissioning of nine 1-meter telescopes at McDonald Observatory (Texas), Cerro Tololo (Chile), SAAO (South Africa) and Siding Spring Observatory (Australia). The telescope network is now operating and observations are being executed remotely and robotically. I am using the LCOGT network to confirm newly detected NEO candidates produced by the major sky surveys such as Catalina Sky Survey (CSS) and PanSTARRS (PS1). An increasing amount of time is being spent to obtain follow-up astrometry and photometry for radar-targeted objects in order to improve the orbits and determine the rotation periods. This will be extended to obtain more light curves of other NEOs which could be Near-Earth Object Human Space Flight Accessible Targets Study (NHATS) or Asteroid Retrieval Mission (ARM) targets. Recent results have included the first period determination for the Apollo 2002 NV16 and our first NEO spectrum from the FLOYDS spectrographs on the LCOGT 2m telescopes obtained for 2012 DA14 during the February 2013 closepass.
NEOPROP: A NEO Propagator for Space Situational Awareness

NASA Astrophysics Data System (ADS)

Zuccarelli, Valentino; Bancelin, David; Weikert, Sven; Thuillot, William; Hestroffer, Daniel; Yabar Valle, Celia; Koschny, Detlef

2013-09-01

The overall aim of the Space Situational Awareness (SSA) Preparatory Programme is to support the European independent utilisation of and access to space for research or services, through providing timely and quality data, information, services and knowledge regarding the environment, the threats and the sustainable exploitation of the outer space surrounding our planet Earth. The SSA system will comprise three main segments:• Space Weather (SWE) monitoring and forecast• Near-Earth Objects (NEO) survey and follow-up• Space Surveillance and Tracking (SST) of man-made space objectsCurrently, there are over 600.000 asteroids known in our Solar System, where more than 9.500 of these are NEOs. These could potentially hit our planet and depending on their size could produce considerable damage. For this reason NEOs deserve active detection and tracking efforts.The role of the SSA programme is to provide warning services against potential asteroid impact hazards, including discovery, identification, orbit prediction and civil alert capabilities. ESA is now working to develop a NEO Coordination Centre which will later evolve into a SSA-NEO Small Bodies Data Centre (SBDC), located at ESA/ESRIN, Italy. The Software prototype developed in the frame of this activity may be later implemented as a part of the SSA-NEO programme simulators aimed at assessing the trajectory of asteroids. There already exist different algorithms to predict orbits for NEOs. The objective of this activity is to come up with a different trajectory prediction algorithm, which allows an independent validation of the current algorithms within the SSA-NEO segment (e.g. NEODyS, JPL Sentry System).The key objective of this activity was to design, develop, test, verify, and validate trajectory prediction algorithm of NEOs in order to be able to computeanalytically and numerically the minimum orbital intersection distances (MOIDs).The NEOPROP software consists of two separate modules/tools:1. The Analytical Module makes use of analytical algorithms in order to rapidly assess the impact risk of a NEO. It is responsible for the preliminary analysis. Orbit Determination algorithms, as the Gauss and the Linear Least Squares (LLS) methods, will determine the initial state (from MPC observations), along with its uncertainty, and the MOID of the NEO (analytically).2. The Numerical Module makes use of numerical algorithms in order to refine and to better assess the impact probabilities. The initial state provided by the orbit determination process will be used to numerically propagate the trajectory. The numerical propagation can be run in two modes: one faster ("fast analysis"), in order to get a fast evaluation of the trajectory and one more precise ("complete analysis") taking into consideration more detailed perturbation models. Moreover, a configurable number of Virtual Asteroids (VAs) will be numerically propagated in order to determine the Earth closest approach. This new "MOID" computation differs from the analytical one since it takes into consideration the full dynamics of the problem.
The Impact Hazard

NASA Technical Reports Server (NTRS)

Morrison, David

1994-01-01

The Earth has been subject to hypervelocity impacts from comets and asteroids since its formation, and such impacts have played an important role in the evolution of life on our planet. We now recognize not only the historical role of impacts, but the contemporary hazard posed by such events. In the absence of a complete census of potentially threatening Earth-crossing asteroids or comets (called collectively Near Earth Objects, or NEOs), or even of a comprehensive cur-rent search program to identify NEOs, we can consider the hazard only from a probabilistic perspective. We know the steep power-law relationship between NEO numbers and size, with many more small bodies than large ones. We also know that few objects less than about 50 m in diameter (with kinetic energy near 10 megatons) penetrate the atmosphere and are capable of doing surface damage. But there is a spectrum of possible impact hazards associated with objects from this 10-megaton threshold all the way up to NEOs 5 km or larger in diameter, which are capable of inflicting severe damage on the environment, leading to mass extinction's of species. Detailed analysis has shown that, in general, the larger the object the greater the hazard, even when allowance is made for the infrequency of large impacts. Most of the danger to human life is associated with impacts by objects roughly 2 km or larger (energy greater than 1 million megatons), which can inject sufficient submicrometer dust into the atmosphere to produce a severe short-term global cooling with subsequent loss of crops, leading to starvation. Hazard estimates suggest that the chance of such an event occurring during a human lifetime is about 1:5000, and the global probability of death from such impacts is of the order of 1:20000, values that can be compared with risks associated with other natural hazards such as earthquakes, volcanic eruptions, and severe storms. However, the impact hazard differs from the others in that it can be largely prevented by a comprehensive survey for threatening objects and the application of technological solutions to deflect or destroy objects that are found to have orbits that will lead to collision with the Earth.
Characterization of NEOs from the Policy Perspective: Implications from Problem and Solution Definitions

NASA Astrophysics Data System (ADS)

Lindquist, E.

2015-12-01

The characterization of near-Earth-objects (NEOs) in regard to physical attributes and potential risk and impact factors presents a complex and complicates scientific and engineering challenge. The societal and policy risks and impacts are no less complex, yet are rarely considered in the same context as material properties or related factors. The objective of this contribution is to position the characterization of NEOs within the public policy process domain as a means to reflect on the science-policy nexus in regard to risks associated with NEOs. This will be accomplished through, first, a brief overview of the science-policy nexus, followed by a discussion of several policy process frameworks, such as agenda setting and the multiple streams model, focusing events, and punctuated equilibrium, and their application and appropriateness to the problem of NEOs. How, too, for example, does NEO hazard and risk compare with other low probability, high risk, hazards in regard to public policy? Finally, we will reflect on the implications of alternative NEO "solutions" and the characterization of the NEO "problem," and the political and public acceptance of policy alternatives as a way to link NEO science and policy in the context of the overall NH004 panel.
Survey and Risk Assessment of Near Earth Asteroids

NASA Astrophysics Data System (ADS)

Zhao, H. B.

2010-07-01

In 1994, 21 fragments of comet Shoemaker-Levy 9 impacted Jupiter with a velocity of about 60 km/s, which is the first grand collision between celestial bodies observed by human beings. The impact makes us informed definitely that the earth is faced with the small but serious threat of Near Earth Objects (NEOs). Chinese scientists of Purple Mountain Observatory proposed a plan of Chinese Near Earth Object Survey (CNEOS) in the conference on NEOs held in the building of the World Headquarters of United Nations, New York in 1995. This project started in 1998. During the past 7 years, CNEOS proceeded in selecting observational site, manufacturing telescope and CCD detector, carrying out observation, reducing mass data, and assessing impact risk from NEOs. Will those so-called potential hazardous asteroids be the terminator of mankind? In 2007, NASA proposed the Spaceguard goal to detect, track, catalogue and characterize 90% of the potentially hazardous objects with diameters greater than 140 m. This dissertation reviews the current situation of research on asteroids and NEOs, which will greatly enhance our understanding of the planetary sciences. The project of CNEOS, including selecting observational site, manufacturing telescope and CCD detector, had been put in practice since 1998. The telescope of CNEOS is a 1.04/1.20/1.80 m Schmidt telescope, equipped with a 4096 by 4096 CCD detector which has drift-scanning function. In this dissertation, the advantage and disadvantage of drift-scanning and corresponding observational method are discussed. This dissertation discusses residential district of asteroids and distribution of visual magnitudes of asteroids. As a result, we draw three principles of observational plan. This dissertation also develops algorithms of pretreatment of astronomical image, extracting objects, and cross-identification, then discusses the methods of identifying and classifying of move objects, establishes software to realize the reduction of the mass data. Until November 2007, CNEOS had found 332 new asteroids including an Apollo type NEO and a Jupiter-family periodic comet. The observation quantity of CNEOS ranked the eighth among all 378 asteroid observation plans, and the accuracy of positional reduction was also quite well. The dissertation carries out the research of dynamics of asteroids. A software on orbit determination, differential correction, dynamical evolution and asteroid ephemeris is reconstructed. This dissertation reviews the history of impact prediction theory, and covers the linear techniques for analyzing encounters, consisting of precise orbit determination and propagation followed by target plane analysis. The impact probabilities and risks between three NEOs and the earth in 200 years are calculated. In this dissertation, a set of numerical algorithms are built to discuss the observational prediction of Northern Taurids under the effect of the lunar gravitational assembling in 2011. In addition, the earth satellite measurement, the lunar orbiter measurement and lunar laser ranging measurement are used to constrain the intermediate-range gravity from λ = 1.2×107 ˜ 3.8 × 108 m.
DOE Office of Scientific and Technical Information (OSTI.GOV)

Mainzer, A.; Masiero, J.; Bauer, J.

Enhancements to the science data processing pipeline of NASA's Wide-field Infrared Survey Explorer (WISE) mission, collectively known as NEOWISE, resulted in the detection of >158,000 minor planets in four infrared wavelengths during the fully cryogenic portion of the mission. Following the depletion of its cryogen, NASA's Planetary Science Directorate funded a four-month extension to complete the survey of the inner edge of the Main Asteroid Belt and to detect and discover near-Earth objects (NEOs). This extended survey phase, known as the NEOWISE Post-Cryogenic Survey, resulted in the detection of {approx}6500 large Main Belt asteroids and 86 NEOs in its 3.4more » and 4.6 {mu}m channels. During the Post-Cryogenic Survey, NEOWISE discovered and detected a number of asteroids co-orbital with the Earth and Mars, including the first known Earth Trojan. We present preliminary thermal fits for these and other NEOs detected during the 3-Band Cryogenic and Post-Cryogenic Surveys.« less
Mapping Near-Earth Hazards

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2016-06-01

How can we hunt down all the near-Earth asteroids that are capable of posing a threat to us? A new study looks at whether the upcoming Large Synoptic Survey Telescope (LSST) is up to the job.Charting Nearby ThreatsLSST is an 8.4-m wide-survey telescope currently being built in Chile. When it goes online in 2022, it will spend the next ten years surveying our sky, mapping tens of billions of stars and galaxies, searching for signatures of dark energy and dark matter, and hunting for transient optical events like novae and supernovae. But in its scanning, LSST will also be looking for asteroids that approach near Earth.Cumulative number of near-Earth asteroids discovered over time, as of June 16, 2016. [NASA/JPL/Chamberlin]Near-Earth objects (NEOs) have the potential to be hazardous if they cross Earths path and are large enough to do significant damage when they impact Earth. Earths history is riddled with dangerous asteroid encounters, including the recent Chelyabinsk airburst in 2013, the encounter that caused the kilometer-sized Meteor Crater in Arizona, and the impact thought to contribute to the extinction of the dinosaurs.Recognizing the potential danger that NEOs can pose to Earth, Congress has tasked NASA with tracking down 90% of NEOs larger than 140 meters in diameter. With our current survey capabilities, we believe weve discovered roughly 25% of these NEOs thus far. Now a new study led by Tommy Grav (Planetary Science Institute) examines whether LSST will be able to complete this task.Absolute magnitude, H, of asynthetic NEO population. Though these NEOs are all larger than 140 m, they have a large spread in albedos. [Grav et al. 2016]Can LSST Help?Based on previous observations of NEOs and resulting predictions for NEO properties and orbits, Grav and collaborators simulate a synthetic population of NEOs all above 140 m in size. With these improved population models, they demonstrate that the common tactic of using an asteroids absolute magnitude as a proxy for its size is a poor approximation, due to asteroids large spread in albedos. Roughly 23% of NEOs larger than 140 m have absolute magnitudes fainter than H = 22 mag, the authors show which is the value usually assumed as the default absolute magnitude of a 140 m NEO.Fraction of NEOs weve detected as a function of time based on the authors simulations of the current surveys (red), LSST plus the current surveys (black), NEOCam plus the current surveys (blue), and the combined result for all surveys (green). [Grav et al. 2016]Taking this into account, Grav and collaborators then use information about the planned LSST survey strategies and detection limits to test what fraction of this synthetic NEO population LSST will be able to detect in its proposed 10-year mission.The authors find that, within 10 years, LSST will likely be able to detect only 63% of NEOs larger than 140 m. Luckily, LSST may not have to work alone; in addition to the current surveys in operation, a proposed infrared space-based survey mission called NEOCam is planned for launch in 2021. If NEOCam is funded, it will complement LSSTs discovery capabilities, potentially allowing the two surveys to jointly achieve the 90% detection goal within a decade.CitationT. Grav et al 2016 AJ 151 172. doi:10.3847/0004-6256/151/6/172
A New and Improved Model of the Near-Earth Object Population

NASA Astrophysics Data System (ADS)

Bottke, W. F., Jr.; Granvik, M.; Morbidelli, A.; Jedicke, R.; Bolin, B.; Beshore, E. C.; Vokrouhlicky, D.; Nesvorny, D.; Michel, P.

2014-12-01

This is a golden age for near-Earth Object (NEO) research. We have discovered some 90% of the most threatening NEOs, while ongoing surveys are finding many sub-km NEOs as well. NEO physical characterization studies by missions, space- and ground-based observatories are also revolutionizing our ideas about what NEOs are like. President Obama announced on April 15, 2010 that NASA would send astronauts to an NEA by 2025; this remains Administration policy. The Feb. 15, 2013 explosion of an NEO over Chelyabinsk, Russia, has further boosted interest in NEOs. This increasing interest, and a vast array of new data, have led us to re-investigate the debiased orbital and absolute magnitude distribution of the NEO population. Such models are asboluetly needed to make accurate predictions about NEOs that are likely exploration targets for human and robotic spacecraft. Using the methods of Bottke et al. (2002), we numerically tracked a large unbiased sample of asteroids escaping the main belt and TNO populations in order to locate all possible NEO source regions. From here, we recorded the orbital evolution of the bodies that entering the NEO region; their evolutionary pathways were used to create so-called NEO residence-time distributions. They were combined with the calculated observational selection effects for the Catalina Sky Survey, with the model fit to 4,550 NEOs (15 < H < 25) detected by the Catalina Sky Survey's Mt. Lemmon (G96) and Catalina (703) stations between 2005-2012. Our best fit case beautifully reproduces observations and provides us with a new and improved NEO model population. We find our results are in good agreement with the Bottke et al. (2002) model, but we also find many intriguing differences as well: (i) There is an increasing preference for small NEOs to come from the central main belt; (ii) Many low-perihelion-distance NEOs are apparently missing -- we suspect many were removed by a physical destruction mechanism; (iii) We are largely complete in H < 18 Atens and Amors, but we are still missing a good fraction of Apollo NEOs. In our talk, we will discuss our latest findings and will describe the nature of the NEO populations accessible by both ARM and human missions.
Methodology and Results of the Near-Earth Object (NEO) Human Space Flight (HSF) Accessible Targets Study (NHATS)

NASA Technical Reports Server (NTRS)

Barbee, Brent W.; Mink, Ronald G.; Adamo, Daniel R.; Alberding, Cassandra M.

2011-01-01

Near-Earth Asteroids (NEAs) have been identified by the Administration as potential destinations for human explorers during the mid-2020s. Planning such ambitious missions requires selecting potentially accessible targets from the growing known population of 8,008 NEAs. NASA is therefore conducting the Near-Earth Object (NEO) Human Space Flight (HSF) Accessible Targets Study (NHATS), in which the trajectory opportunities to all known NEAs are being systematically evaluated with respect to a set of defined constraints. While the NHATS algorithms have identified hundreds of NEAs which satisfy purposely inclusive trajectory constraints, only a handful of them offer truly attractive mission opportunities in the time frame of greatest interest. In this paper we will describe the structure of the NHATS algorithms and the constraints utilized in the study, present current study results, and discuss various mission design considerations for future human space flight missions to NEAs.

Astrometric and Photometric Follow-Up of Faint Near Earth Objects

NASA Technical Reports Server (NTRS)

Spahr, Timothy

2004-01-01

During the last year, the Near-Earth Object (NEO) follow-up program at Mt. Hopkins funded by the Near-Earth Object Observations (NEOO) program continued to improve. The Principal Investigator was again granted all the requested observing time. In addition to the requested time on the 4 8 in. telescope, 2 nights were also granted on the MMT for observations of extremely faint main-belt asteroids and NEOs. It is expected that the MMT can easily reach V = 25 over a 24 X 24 arcminute field of view. Improvements in the last year included more tweaks to the automatic astrometric routine for higher-quality astrometric fits. Use of the new USNO-B1.0 reference catalog has allowed the PI to push the average RMS of reference star solutions below 0.2 in.. Shift-and- stack techniques are used to improve the signal-to-noise ratio of the target objects. The 48 in. telescope at Mt. Hopkins is completely automated, and can be run remotely from either the Principal Investigator's office at SAO, or even his study at home. Most observing runs are now done remotely.
Physical Characterization of Warm Spitzer-observed Near-Earth Objects

NASA Technical Reports Server (NTRS)

Thomas, Cristina A.; Emery, Joshua P.; Trilling, David E.; Delbo, Marco; Hora, Joseph L.; Mueller, Michael

2014-01-01

Near-infrared spectroscopy of Near-Earth Objects (NEOs) connects diagnostic spectral features to specific surface mineralogies. The combination of spectroscopy with albedos and diameters derived from thermal infrared observations can increase the scientific return beyond that of the individual datasets. For instance, some taxonomic classes can be separated into distinct compositional groupings with albedo and different mineralogies with similar albedos can be distinguished with spectroscopy. To that end, we have completed a spectroscopic observing campaign to complement the ExploreNEOs Warm Spitzer program that obtained albedos and diameters of nearly 600 NEOs (Trilling et al., 2010). The spectroscopy campaign included visible and near-infrared observations of ExploreNEOs targets from various observatories. Here we present the results of observations using the low-resolution prism mode (approx. 0.7-2.5 microns) of the SpeX instrument on the NASA Infrared Telescope Facility (IRTF). We also include near-infrared observations of Explore-NEOs targets from the MIT-UH-IRTF Joint Campaign for Spectral Reconnaissance. Our dataset includes near-infrared spectra of 187 ExploreNEOs targets (125 observations of 92 objects from our survey and 213 observations of 154 objects from the MIT survey). We identify a taxonomic class for each spectrum and use band parameter analysis to investigate the mineralogies for the S-, Q-, and V-complex objects. Our analysis suggests that for spectra that contain near-infrared data but lack the visible wavelength region, the Bus-DeMeo system misidentifies some S-types as Q-types. We find no correlation between spectral band parameters and ExploreNEOs albedos and diameters. We investigate the correlations of phase angle with band area ratio and near-infrared spectral slope. We find slightly negative Band Area Ratio (BAR) correlations with phase angle for Eros and Ivar, but a positive BAR correlation with phase angle for Ganymed.The results of our phase angle study are consistent with those of (Sanchez et al., 2012). We find evidence for spectral phase reddening for Eros, Ganymed, and Ivar. We identify the likely ordinary chondrite type analog for an appropriate subset of our sample. Our resulting proportions of H, L, and LL ordinary chondrites differ from those calculated for meteorite falls and in previous studies of ordinary chondrite-like NEOs.
Ground-based Characterization of Earth Quasi Satellite (469219) 2016 HO3

NASA Astrophysics Data System (ADS)

Reddy, Vishnu; Kuhn, Olga; Thirouin, Audrey; Conrad, Al; Malhotra, Renu; Sanchez, Juan A.; Veillet, Christian

2017-10-01

(469219) 2016 HO3 is a small, <100 meter-size, near-Earth object (NEO) that while orbiting the Sun, also appears to circle around the Earth just beyond the Hill sphere as a Earth quasi-satellite. Only five quasi-satellites have been discovered so far, but 2016 HO3 is the most stable of them. The provenance of this object is unknown. On timescales of many centuries, 2016 HO3 remains within 38-100 lunar distance from us making it a prime target for future robotic and human exploration, provided it can be established it is indeed a natural object. In an effort to constrain its rotation period and surface composition, we observed 2016 HO3 on April 14 and 18 2017 (UTC) with the Large Binocular Telescope (LBT) and the Discovery Channel Telescope (DCT). We derive a rotation period of about 28 minutes based on our lightcurve observations. We obtained low-resolution (R ˜ 150 - 500) spectra of 2016 HO3 on 2017 April 14 (UTC) using the pair of MODS spectrographs mounted at the direct Gregorian foci of the LBT, obtaining the entire spectrum from 0.39-0.97 microns simultaneously. The visible wavelength spectrum shows a sharp rise in reflectance between 0.4-0.65 microns with a broad plateau beyond. The scatter near 0.8 microns makes it challenging to confirm the presence of a silicate absorption band at ~1 micron. Color ratios derived from the spectrum all suggest an S taxonomic type. We also derive an updated diameter of 36 meters for 2016 HO3 using an absolute magnitude of 24.3 and S-type albedo of 0.25. The derived rotation period and the spectrum are not uncommon amongst small NEOs, suggesting that 2016 HO3 is a natural object of similar provenance to other small NEOs. NASA Near-Earth Object Observations Program Grant NNX17AJ19G (PI: Reddy) funded parts of this work.
Next Gen NEAR: Near Earth Asteroid Human Robotic Precursor Mission Concept

NASA Technical Reports Server (NTRS)

Rivkin, Andrew S.; Kirby, Karen; Cheng, Andrew F.; Gold, Robert; Kelly, Daniel; Reed, Cheryl; Abell, Paul; Garvin, James; Landis, Rob

2012-01-01

Asteroids have long held the attention of the planetary science community. In particular, asteroids that evolve into orbits near that of Earth, called near-Earth objects (NEO), are of high interest as potential targets for exploration due to the relative ease (in terms of delta V) to reach them. NASA's Flexible Path calls for missions and experiments to be conducted as intermediate steps towards the eventual goal of human exploration of Mars; piloted missions to NEOs are such example. A human NEO mission is a valuable exploratory step beyond the Earth-Moon system enhancing capabilities that surpass our current experience, while also developing infrastructure for future mars exploration capabilities. To prepare for a human rendezvous with an NEO, NASA is interested in pursuing a responsible program of robotic NEO precursor missions. Next Gen NEAR is such a mission, building on the NEAR Shoemaker mission experience at the JHU/APL Space Department, to provide an affordable, low risk solution with quick data return. Next Gen NEAR proposes to make measurements needed for human exploration to asteroids: to demonstrate proximity operations, to quantify hazards for human exploration and to characterize an environment at a near-Earth asteroid representative of those that may be future human destinations. The Johns Hopkins University Applied Physics Laboratory has demonstrated exploration-driven mission feasibility by developing a versatile spacecraft design concept using conventional technologies that satisfies a set of science, exploration and mission objectives defined by a concept development team in the summer of 2010. We will describe the mission concept and spacecraft architecture in detail. Configuration options were compared with the mission goals and objectives in order to select the spacecraft design concept that provides the lowest cost, lowest implementation risk, simplest operation and the most benefit for the mission implementation. The Next Gen NEAR spacecraft was designed to support rendezvous with a range of candidate asteroid targets and could easily be launched with one of several NASA launch vehicles. The Falcon 9 launch vehicle supports a Next Gen NEAR launch to target many near-Earth asteroids under consideration that could be reached with a C3 of 18 km2/sec2 or less, and the Atlas V-401 provides added capability supporting launch to NEAs that require more lift capacity while at the same time providing such excess lift capability that another payload of opportunity could be launch in conjunction with Next Gen NEAR. Next Gen NEAR will measure and interact with the target surface in ways never undertaken at an asteroid, and will prepare for first human precursor mission by demonstrating exploration science operations at an accessible NEO. This flexible mission and spacecraft design concept supports target selection based on upcoming Earth-based observations and also provides opportunities for co-manifest & international partnerships. JHU/APL has demonstrated low cost, low risk, high impact missions and this mission will help to prepare NASA for human NEO exploration by combining the best of NASA s human and robotic exploration capabilities.
NEO follow-up, recovery and precovery campaigns at the ESA NEO Coordination Centre

NASA Astrophysics Data System (ADS)

Micheli, Marco; Koschny, Detlef; Drolshagen, Gerhard; Perozzi, Ettore; Borgia, Barbara

2016-01-01

The NEO Coordination Centre (NEOCC) has been established within the framework of the ESA Space Situational Awareness (SSA) Programme. Among its tasks are the coordination of observational activities and the distribution of up-to-date information on NEOs through its web portal. The Centre is directly involved in observational campaigns with various telescopes, including ESO's VLT and ESA's OGS telescope. We are also developing a network of collaborating observatories, with a variety of capabilities, which are alerted when an important observational opportunity arises. From a service perspective, the system hosted at the NEOCC collects information on NEOs produced by European services and makes it available to users, with a focus on objects with possible collisions with the Earth. Among the tools provided via our portal are the Risk List of all known NEOs with impact solutions, and the Priority List, which allows observers to identify NEOs in most urgent need of observations.
Why Atens Enjoy Enhanced Accessibility For Human Space Flight

NASA Technical Reports Server (NTRS)

Barbee, Brent; Adamo, Daniel

2011-01-01

In the context of human space flight (HSF), the concept of near-Earth object (NEO) accessibility is highly subjective. Whether or not a particular NEO is accessible critically depends on mass, performance, and reliability of interplanetary HSF systems yet to be designed. Such systems would certainly include propulsion and crew life support with adequate shielding from both solar flares and galactic cosmic radiation. Equally critical architecture options are relevant to NEO accessibility. These options are also far from being determined and include the number of launches supporting an HSF mission, together with whether or not consumables are to be pre-emplaced at the destination. Until the unknowns of HSF to NEOs come into clearer focus, the notion of relative accessibility is of great utility. Imagine a group of NEOs, each with nearly equal HSF merit determined from their individual characteristics relating to crew safety, scientific return, resource utilization, and planetary defense. The more accessible members of this group are more likely to be explored first. A highly accessible NEO could conceivably be deferred in favor of a less accessible HSF destination because the latter is more accessible during a programmatically desirable launch compliant mission trajectory solutions detected in association with a specific NEO. The known NEO population is then surveyed to illustrate in which regions of heliocentric semi-major axis, eccentricity, and inclination (a, e, i) space NEOs with large n values are mapped. The (a, e, i) mapping is also formatted such that membership in each of four NEO orbit classifications, as defined below, is evident. Amors have orbits everywhere superior to (outside of) Earth's. An Amor is therefore defined to have perihelion between 1.017 astronomical units (AU) and the maximum NEO value of 1.3 AU. As of 0 hrs Universal Time on 1 January 2011 (UT epoch 2011.0), Amors numbered 2855 in the Jet Propulsion Laboratory (JPL) Small-Body Database (SBDB), comprising 37.7% of known NEOs. Apollos have orbits crossing Earth's with periods greater than Earth's. An Apollo is therefore defined to have perihelion less than 1.017 AU and a greater than 1.0 AU. As of 2011.0 UT, Apollos numbered 4080 in the SBDB, comprising 53.9% of known NEOs. Atens have orbits crossing Earth's with periods less than Earth's. An Aten is therefore defined to have aphelion greater than 0.983 AU and a less than 1.0 AU. As of 2011.0 UT, Atens numbered 618 in the SBDB, comprising 8.2% of known NEOs. Atiras have orbits everywhere inferior to (inside of) Earth's. An Atira is therefore defined to have aphelion less than 0.983 AU. As of 2011.0 UT, Atiras numbered 11 in the SBDB, comprising 0.1% of known NEOs. It is no surprise that the largest n values are chiefly associated with Apollos and Atens. Because these orbits cross Earth's, distance to be covered in a given round trip mission time delta-t can be far less than is possible for Amors or Atiras . This delta-t or the sum of mission propulsive impulse magnitudes delta-v can more frequently be minimized to enhance NHATS compliance for Apollos and Atens than is generally the case for Amors and Atiras. A less intuitive trend in NHATS results is that Atens nearly outnumber the more numerous Apollos among the most compliant NEOs as measured by n. This trend is completely out of proportion to the degree Atens are represented among the known NEO population. A theory based on geocentric NEO dynamics is presented by this paper to explain why Atens enjoy inherently greater accessibility than do Apollos. Another trend evident from mapping into (a, e, i) space is the dearth of known NEOs at low e when a < 1 AU. Underrepresentation of Atens and Atiras in the NEO catalog is at least in part attributable to observing exclusively from a perspective near Earth. Generally inferior Aten and Atira orbits are rarely, if ever, in Earth's night sky. Until a comprehensive NEO survey is conducted from an appropriateegion remote from Earth, the theory developed in this paper indicates a substantial fraction of the most accessible NEOs will remain unknown. season. Such a season is really yet another undetermined HSF architecture option. A launch season's duration will likely be measured in weeks, and it will be utilized at an indeterminate point almost certainly more than a decade in the future when HSF programmatic maturity is sufficient. Furthermore, current knowledge of the NEO population relevant to HSF is far from complete. In the 100-m-diameter class of greatest interest, only a few percent of the estimated NEO population is known [2, Figure 2.4]. Therefore, any known, lost, or fictitious NEO in a highly accessible orbit is a potential HSF destination of merit. Even if lost, fictitious, small, or hazardous, such a potential target (or another in a similar orbit) may ultimately prove to be an early HSF destination when the pertinent NEO population is more thoroughly catalogued and NEO orbits are more thoroughly maintained at high accuracy. This paper first reviews methodology and pertinent results from NASA-sponsored research performed in late 2010 and dubbed NEO HSF Accessible Targets Study (NHATS, pronounced as "gnats"). A useful accessibility metric developed during this study is n, the tally of NHATS-
The future of planetary defense

NASA Astrophysics Data System (ADS)

Mainzer, A.

2017-04-01

Asteroids and comets have impacted Earth in the past and will do so in the future. While the frequency of impacts is reasonably well understood on geologic timescales, it is difficult to predict the next sizeable impact on human timescales by extrapolation from population statistics alone. Fortunately, by identifying and tracking individual objects, we can make precise predictions of any potential close encounters with Earth. As more advance notice is provided, the range of possible mitigation options expands. While the chance of an impact is very small, the potential consequences can be severe, meaning that sensible risk reduction measures should be undertaken. By implementing surveys, the risk of an unforeseen impact can be greatly reduced: the first step is finding the objects. Fortunately, the worldwide community of professional and amateur astronomers has made significant progress in discovering large near-Earth objects (NEOs). More than 95% of NEOs capable of causing global devastation (objects larger than 1 km in diameter) have been discovered, and none of these pose an impact hazard in the near future. Infrastructure is in place to link observations and compute close approaches in real time. Interagency and international collaborations have been undertaken to strengthen cooperative efforts to plan potential mitigation and civil defense campaigns. Yet much remains to be done. Approximately 70% of NEOs larger than 140 m (large enough to cause severe regional damage) remain undiscovered. With the existing surveys, it will take decades to identify the rest. Progress can be accelerated by undertaking new surveys with improved sensitivity.Plain Language SummaryAsteroids and comets have impacted Earth in the past and will do so in the future. Fortunately, by identifying and tracking them, we have the ability to predict any potential close encounters with Earth. By observing the sky repeatedly to search for near-Earth objects, the risk of an unforeseen impact can be greatly reduced; the first step is finding them. While much progress has been made by the astronomical community, much work remains to be done. About 70% of the near-Earth objects large enough to cause severe regional damage have yet to be discovered. Without investment in advanced search systems, it will take many decades to find these objects. While the chance of an impact is small, the consequences can potentially be severe, so reasonable measures (such as finding, tracking, and characterizing the asteroids) should be undertaken. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EPSC...11.1024D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EPSC...11.1024D">NASA's Planetary Defense Coordination Office at NASA HQ</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Daou, D.; Johnson, L.; Fast, K. E.; Landis, R.; Friedensen, V. P.; Kelley, M. 2017-09-01 NASA and its partners maintain a watch for near-Earth objects (NEOs), asteroids and comets that pass close to the Earth, as part of an ongoing effort to discover, catalog, and characterize these bodies. The PDCO is responsible for: • Ensuring the early detection of potentially hazardous objects (PHOs) - asteroids and comets whose orbit are predicted to bring them within 0.05 Astronomical Units of Earth; and of a size large enough to reach Earth's surface - that is, greater than perhaps 30 to 50 meters; • Tracking and characterizing PHOs and issuing warnings about potential impacts; • Providing timely and accurate communications about PHOs; and • Performing as a lead coordination node in U.S. Government planning for response to an actual impact threat. The PDCO collaborates with other U.S. Government agencies, other national and international agencies, and professional and amateur astronomers around the world. The PDCO also is responsible for facilitating communications between the science community and the public should any potentially hazardous NEO be discovered. In addition, the PDCO works closely with the United Nations Office of Outer Space Affairs, its Committee on the Peaceful Uses of Outer Space, and its Action Team on Near Earth Objects (also known as Action Team 14). The PDCO is a leading member of the International Asteroid Warning Network (IAWN) and the Space Missions Planning Advisory Group (SMPAG), multinational endeavors recommended by the United Nations for an international response to the NEO impact hazard and established and operated by the spacecapable nations. The PDCO also communicates with the scientific community through channels such as NASA's Small Bodies Assessment Group (SBAG). In this talk, we will provide an update to the office's various efforts and new opportunities for partnerships in the continuous international effort for Planetary Defense. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMNH13A0102D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMNH13A0102D">NASA's Planetary Defense Coordination Office at NASA HQ</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Daou, D.; Johnson, L.; Fast, K. E.; Landis, R.; Friedensen, V. P.; Kelley, M. 2017-12-01 NASA and its partners maintain a watch for near-Earth objects (NEOs), asteroids and comets that pass close to the Earth, as part of an ongoing effort to discover, catalog, and characterize these bodies. The PDCO is responsible for: Ensuring the early detection of potentially hazardous objects (PHOs) - asteroids and comets whose orbit are predicted to bring them within 0.05 Astronomical Units of Earth; and of a size large enough to reach Earth's surface - that is, greater than perhaps 30 to 50 meters; Tracking and characterizing PHOs and issuing warnings about potential impacts; Providing timely and accurate communications about PHOs; and Performing as a lead coordination node in U.S. Government planning for response to an actual impact threat. The PDCO collaborates with other U.S. Government agencies, other national and international agencies, and professional and amateur astronomers around the world. The PDCO also is responsible for facilitating communications between the science community and the public should any potentially hazardous NEO be discovered. In addition, the PDCO works closely with the United Nations Office of Outer Space Affairs, its Committee on the Peaceful Uses of Outer Space, and its Action Team on Near Earth Objects (also known as Action Team 14). The PDCO is a leading member of the International Asteroid Warning Network (IAWN) and the Space Missions Planning Advisory Group (SMPAG), multinational endeavors recommended by the United Nations for an international response to the NEO impact hazard and established and operated by the space-capable nations. The PDCO also communicates with the scientific community through channels such as NASA's Small Bodies Assessment Group (SBAG). In this talk, we will provide an update to the office's various efforts and new opportunities for partnerships in the continuous international effort for Planetary Defense. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MNRAS.476.4481B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MNRAS.476.4481B">Small D-type asteroids in the NEO population: new targets for space missions</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Barucci, Maria Antonietta; Perna, D.; Popescu, M.; Fornasier, S.; Doressoundiram, A.; Lantz, C.; Merlin, F.; Fulchignoni, M.; Dotto, E.; Kanuchova, S. 2018-06-01 In the framework of the Near Earth Objects (NEOs) observational campaign carried out within the NEOShield-2 project, we identify nine new small D-type asteroids with estimated diameter less than 600 m. The link with meteorites for this class of asteroids is weak and the best fit obtained is with the Tagish Lake meteorite for seven of them. D-type asteroids are believed to contain the most pristine material of the Solar system and could have delivered the pre-biotic material to the Earth. Our results double the known sample of the D-types in the NEO population and triple the candidates of this class for a sample-return mission (at very low ΔV). Our finding increases considerably the number of targets for sample-return mission. A sample-return mission to a D-type asteroid will provide a major progress in understanding the early history of the Solar system and to investigate the origin of life on the Earth. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20050203970&hterms=photometric&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dphotometric','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20050203970&hterms=photometric&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dphotometric">Astrometric and Photometric Follow-up of Faint Near Earth Objects</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Morgan, T. (Technical Monitor); Spahr, Timothy 2005-01-01 During the period April 2003 - April 2005, roughly 150 different faint NEO's were observed using the 1.2-m telescope at Mt. Hopkins. Among these were a couple of spacecraft/radar targets, including support observations in support of the Deep Impact mission. While not strictly an NEO target, comet P/Tempel 1 was nonetheless observed as an object of very high importance. During this time and independent contractor, Kyle Smalley, was trained in the use of the telescope and provided some basic software support for the project. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013DPS....4520824E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013DPS....4520824E">LINNAEUS: BOOSTING NEAR EARTH ASTEROID CHARACTERIZATION RATES</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Elvis, Martin; Beeson, C.; Galache, J.; DeMeo, F.; Evans, I.; Evans, J.; Konidaris, N.; Najita, J.; Allen, L.; Christensen, E.; Spahr, T. 2013-10-01 Near Earth objects (NEOs) are being discovered at a rate of about 1000 per year, and this rate is set to double by 2015. However, the physical characterization of NEOs is only ~100 per year for each type of follow-up observation. We have proposed the LINNAEUS program to NASA to raise the characterization rate of NEOs to the rate of their discovery. This rate matching is necessary as any given NEO is only available for a relatively short time (days to weeks), and they are usually fainter on subsequent apparitions. Hence follow-up observations must be initiated rapidly, without time to cherry-pick the optimum objects. LINNAEUS concentrates on NEO composition. Optical spectra, preferably extending into the near-infrared, provide compositions that can distinguish major compositional classes of NEOs with reasonable confidence (Bus and Binzel 2002, DeMeo et al. 2009). Armed with a taxonomic type the albedo, pV, of an NEO is better constrained, leading to more accurate sizes and masses. Time-resolved spectroscopy can give indications of period, axial ratio and surface homogeneity. A reasonable program of spectroscopy could keep pace with the NEO discovery rate. A ground-based telescope can observe faint NEOs about 210 nights a year, due to time lost due to weather, bright time, and equipment downtime (e.g. Gemini), for a total of ~2000 hours/year. At 1 hour per NEO spectrum, a well-run, dedicated, telescope could obtain almost 2000 spectra per year, about the rate required. If near-IR spectra are required then a 4 m or larger telescope is necessary to reach 20. However, if the Bus-Binzel taxomonmy suffices then only optical spectra are needed and a 2 meter class telescope is sufficient. LINNAEUS would use 50% of the KPNO 2.1 m telescope with an IFU spectrometer, the SED-machine (Ben-Ami et al. 2013), to obtain time-resolved optical spectra of 1200-2000 NEOs/year, or 4200-7000 in 3.5 years observing in an NEOO program. Robust pipeline analysis will release taxonomic types via the Minor Planet Center within 24 hours and a full archive of spectra and products will be provided. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AcAau.107..247W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AcAau.107..247W">Target selection for a hypervelocity asteroid intercept vehicle flight validation mission</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Wagner, Sam; Wie, Bong; Barbee, Brent W. 2015-02-01 Asteroids and comets have collided with the Earth in the past and will do so again in the future. Throughout Earth's history these collisions have played a significant role in shaping Earth's biological and geological histories. The planetary defense community has been examining a variety of options for mitigating the impact threat of asteroids and comets that approach or cross Earth's orbit, known as near-Earth objects (NEOs). This paper discusses the preliminary study results of selecting small (100-m class) NEO targets and mission analysis and design trade-offs for validating the effectiveness of a Hypervelocity Asteroid Intercept Vehicle (HAIV) concept, currently being investigated for a NIAC (NASA Advanced Innovative Concepts) Phase 2 study. In particular this paper will focus on the mission analysis and design for single spacecraft direct impact trajectories, as well as several mission types that enable a secondary rendezvous spacecraft to observe the HAIV impact and evaluate it's effectiveness. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110016598','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110016598">Large Bodies Associated with Meteoroid Streams</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Badadzhanov, P. B.; William, I. P.; Kokhirova, G. I. 2011-01-01 It is now accepted that some near-Earth objects (NEOs) may be dormant or dead comets. One strong indicator of cometary nature is the existence of an associated meteoroid stream with its consequently observed meteor showers. The complexes of NEOs which have very similar orbits and a likely common progenitor have been identified. The theoretical parameters for any meteor shower that may be associated with these complexes were calculated. As a result of a search of existing catalogues of meteor showers, activity has been observed corresponding to each of the theoretically predicted showers was found. We conclude that these asteroid-meteoroid complexes of four NEOs moving within the Piscids stream, three NEOs moving within the Iota Aquariids stream, and six new NEOs added to the Taurid complex are the result of a cometary break-up. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170001430','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170001430">Hybrid Guidance Control for a Hypervelocity Small Size Asteroid Interceptor Vehicle</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Zebenay, Melak M.; Lyzhoft, Joshua R.; Barbee, Brent W. 2017-01-01 Near-Earth Objects (NEOs) are comets and/or asteroids that have orbits in proximity with Earth's own orbit. NEOs have collided with the Earth in the past, which can be seen at such places as Chicxulub crater, Barringer crater, and Manson crater, and will continue in the future with potentially significant and devastating results. Fortunately such NEO collisions with Earth are infrequent, but can happen at any time. Therefore it is necessary to develop and validate techniques as well as technologies necessary to prevent them. One approach to mitigate future NEO impacts is the concept of high-speed interceptor. This concept is to alter the NEO's trajectory via momentum exchange by using kinetic impactors as well as nuclear penetration devices. The interceptor has to hit a target NEO at relative velocity which imparts a sufficient change in NEO velocity. NASA's Deep Impact mission has demonstrated this scenario by intercepting Comet Temple 1, 5 km in diameter, with an impact relative speed of approximately 10 km/s. This paper focuses on the development of hybrid guidance navigation and control (GNC) algorithms for precision hypervelocity intercept of small sized NEOs. The spacecraft's hypervelocity and the NEO's small size are critical challenges for a successful mission as the NEO will not fill the field of view until a few seconds before intercept. The investigation needs to consider the error sources modeled in the navigation simulation such as spacecraft initial state uncertainties in position and velocity. Furthermore, the paper presents three selected spacecraft guidance algorithms for asteroid intercept and rendezvous missions. The selected algorithms are classical Proportional Navigation (PN) based guidance that use a first order difference to compute the derivatives, Three Plane Proportional Navigation (TPPN), and the Kinematic Impulse (KI). A manipulated Bennu orbit that has been changed to impact Earth will be used as a demonstrative example to compare the three methods. In addition, a hybrid approach that is a combination between proportional navigation and kinematic impulse will be investigated to find an effective, error tolerant, and power saving approach. A 3-dimension mission scenario for both the asteroid and the interceptor spacecraft software simulator is developed for testing of the controllers. The current result demonstrates that a miss distance magnitude of less than 10m is found using the PN and TPPN guidance laws for small asteroid in the presence of error in the spacecraft states. Moreover, the paper presents these results and also the hybrid control approach simulation results. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090020399','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090020399">NEOCAM: Near Earth Object Chemical Analysis Mission: Bridging the Gulf between Telescopic Observations and the Chemical and Mineralogical Compositions of Asteroids or Diogenes A: Diagnostic Observation of the Geology of Near Earth Spectrally-Classified Asteroids</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Nuth, Joseph A. 2009-01-01 Studies of meteorites have yielded a wealth of scientific information based on highly detailed chemical and isotopic studies possible only in sophisticated terrestrial laboratories. Telescopic studies have revealed an enormous (greater than 10(exp 5)) number of physical objects ranging in size from a few tens of meters to several hundred kilometers, orbiting not only in the traditional asteroid belt between Mars and Jupiter but also throughout the inner solar system. Many of the largest asteroids are classed into taxonomic groups based on their observed spectral properties and are designated as C, D. X, S or V types (as well as a wide range in sub-types). These objects are certainly the sources far the meteorites in our laboratories, but which asteroids are the sources for which meteorites? Spectral classes are nominally correlated to the chemical composition and physical characteristics of the asteroid itself based on studies of the spectral changes induced in meteorites due to exposure to a simulated space environment. While laboratory studies have produced some notable successes (e.g. the identification of the asteroid Vesta as the source of the H, E and D meteorite classes), it is unlikely that we have samples of each asteroidal spectral type in our meteorite collection. The correlation of spectral type and composition for many objects will therefore remain uncertain until we can return samples of specific asteroid types to Earth for analyses. The best candidates for sample return are asteroids that already come close to the Earth. Asteroids in orbit near 1 A.U. have been classified into three groups (Aten, Apollo & Amor) based on their orbital characteristics. These Near Earth Objects (NEOs) contain representatives of virtually all spectral types and sub-types of the asteroid population identified to date. Because of their close proximity to Earth, NEOs are prime targets for asteroid missions such as the NEAR-Shoemaker NASA Discovery Mission to Eros and the Japanese Hyabusa Mission to Itokawa. Also due to their close proximity to Earth, NEOs constitute the most likely set of celestial objects that will impact us in the relatively near future. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014htu..conf...55C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014htu..conf...55C">The Catalina Sky Survey for Near-Earth Objects</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Christensen, E. The Catalina Sky Survey (CSS) specializes in the detection of the closest transients in our transient universe: near-Earth objects (NEOs). CSS is the leading NEO survey program since 2005, with a discovery rate of 500-600 NEOs per year. This rate is set to substantially increase starting in 2014 with the deployment of wider FOV cameras at both survey telescopes, while a proposed 3-telescope system in Chile would provide a new and significant capability in the Southern Hemisphere beginning as early as 2015. Elements contributing to the success of CSS may be applied to other surveys, and include 1) Real-time processing, identification, and reporting of interesting transients; 2) Human-assisted validation to ensure a clean transient stream that is efficient to the limits of the system (˜ 1σ); 3) an integrated follow-up capability to ensure threshold or high-priority transients are properly confirmed and followed up. Additionally, the open-source nature of the CSS data enables considerable secondary science (i.e. CRTS), and CSS continues to pursue collaborations to maximize the utility of the data. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AcAau..84..161L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AcAau..84..161L">The first steps towards a de minimus, affordable NEA exploration architecture</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Landis, Rob R.; Abell, Paul A.; Adamo, Daniel R.; Barbee, Brent W.; Johnson, Lindley N. 2013-03-01 The impetus for asteroid exploration is scientific, political, and pragmatic. The notion of sending human explorers to asteroids is not new. Piloted missions to these primitive bodies were first discussed in the 1960s, pairing Saturn V rockets with enhanced Apollo spacecraft to explore what were then called "Earth-approaching asteroids." Two decades ago, NASA's Space Exploration Initiative (SEI) also briefly examined the possibility of visiting these small celestial bodies. Most recently, the US Human Space Flight Review Committee (the second Augustine Commission) suggested that near-Earth objects (NEOs) represent a target-rich environment for exploration via the "Flexible Path" option. However, prior to seriously considering human missions to NEOs, it has become clear that we currently lack a robust catalog of human-accessible targets. The majority of the known NEOs identified by a study team across several NASA centers as "human-accessible" are probably too small and have orbits that are too uncertain to consider mounting piloted expeditions to these small worlds. The first step in developing a comprehensive catalog is, therefore, to complete a space-based NEO survey. The resulting catalog of candidate NEOs would then be transformed into a matrix of opportunities for robotic and human missions for the next several decades and shared with the international community. This initial step of a space-based NEO survey is therefore the linchpin to laying the foundation of a low-risk architecture to venture out and explore these primitive bodies. We suggest such a minimalist framework architecture from (1) extensive ground-based and precursor spacecraft investigations (while applying operational knowledge from science-driven robotic missions), (2) astronaut servicing of spacecraft operating at geosynchronous Earth orbit to retain essential skills and experience, and (3) applying the sum of these skills, knowledge and experience to piloted missions to NEOs. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018Icar..312..181G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018Icar..312..181G">Debiased orbit and absolute-magnitude distributions for near-Earth objects</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Granvik, Mikael; Morbidelli, Alessandro; Jedicke, Robert; Bolin, Bryce; Bottke, William F.; Beshore, Edward; Vokrouhlický, David; Nesvorný, David; Michel, Patrick 2018-09-01 The debiased absolute-magnitude and orbit distributions as well as source regions for near-Earth objects (NEOs) provide a fundamental frame of reference for studies of individual NEOs and more complex population-level questions. We present a new four-dimensional model of the NEO population that describes debiased steady-state distributions of semimajor axis, eccentricity, inclination, and absolute magnitude H in the range 17 < H < 25. The modeling approach improves upon the methodology originally developed by Bottke et al. (2000, Science 288, 2190-2194) in that it is, for example, based on more realistic orbit distributions and uses source-specific absolute-magnitude distributions that allow for a power-law slope that varies with H. We divide the main asteroid belt into six different entrance routes or regions (ER) to the NEO region: the ν6, 3:1J, 5:2J and 2:1J resonance complexes as well as Hungarias and Phocaeas. In addition we include the Jupiter-family comets as the primary cometary source of NEOs. We calibrate the model against NEO detections by Catalina Sky Surveys' stations 703 and G96 during 2005-2012, and utilize the complementary nature of these two systems to quantify the systematic uncertainties associated to the resulting model. We find that the (fitted) H distributions have significant differences, although most of them show a minimum power-law slope at H ∼ 20. As a consequence of the differences between the ER-specific H distributions we find significant variations in, for example, the NEO orbit distribution, average lifetime, and the relative contribution of different ERs as a function of H. The most important ERs are the ν6 and 3:1J resonance complexes with JFCs contributing a few percent of NEOs on average. A significant contribution from the Hungaria group leads to notable changes compared to the predictions by Bottke et al. in, for example, the orbit distribution and average lifetime of NEOs. We predict that there are 962-56+52 (802-42+48 ×103) NEOs with H < 17.75 (H < 25) and these numbers are in agreement with the most recent estimates found in the literature (the uncertainty estimates only account for the random component). Based on our model we find that relative shares between different NEO groups (Amor, Apollo, Aten, Atira, Vatira) are (39.4,54.4,3.5,1.2,0.3)%, respectively, for the considered H range and that these ratios have a negligible dependence on H. Finally, we find an agreement between our estimate for the rate of Earth impacts by NEOs and recent estimates in the literature, but there remains a potentially significant discrepancy in the frequency of Tunguska-sized and Chelyabinsk-sized impacts. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002EGSGA..27.6432M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002EGSGA..27.6432M">Electron Density and Temperature Measurements At Mercury Using Thermal Noise Spectroscopy</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Moncuquet, M.; Bougeret, J.-L.; Hellinger, P.; Issautier, K.; Maksimovic, M.; Manning, R.; Meyer-Vernet, N.; Travnicek, P.; Zarka, P. With an innovative procedure, we have constructed a model of the de-biased orbital and magnitude distribution of Near Earth Objects (NEOs), up to absolute magnitude H=22. This model accounts for 4 main sources of Near Earth Objects in the asteroid belt and for extinct Jupiter Family Comets (JFCs). It fits well the orbital-magnitude distribution of the NEOs detected by the Spacewatch Survey, once the observational biases are properly taken into account. The model predicts the existence of 960 NEOs with absolute magnitude H<18 and semimajor axis a<7.8 AU. of these, 58 bodies should be Aten (NEOs with a<1 AU), 590 should be Apollo (NEOs with a>1 AU and perihelion distance q<1 AU) and 310 should be Amor (NEOs with 1<q<1.3). All these numbers scale as a function of the limiting absolute magnitude H by a factor of 10 to the power 0.35(H-18). At present, 425 NEOs with H<18 are known, of which 26, 195 and 204 are Atens, Apollos and Amors, respectively. The current completeness of the known NEO population with H<18 is thus only 45%. Using the albedo distribution in each NEO sources given by a Synthetic main belt As- teroid Model (SAM), we have computed the albedo distribution of NEOs, as a function of their orbital parameters. This model allows to convert the estimated absolute mag- nitude distribution into a size distribution. We predict that the total number of NEOs with D>1km is 834, which, compared to the total number of NEOs with H<18 (963), shows that the usually assumed conversion H=18 <=> D=1km is slightly pessimistic, on average (the exact correspondence would be H=17.82). In a size limited sample, our model predicts that the de-biased ratio between dark and bright (albedo smaller or larger than 0.089) NEOs is 0.8 (I.E., 56% of the NEO with a < 7.4 AU have dark albedos). Moreover, combining our orbital distribution model with the new albedo distribution model, and assuming that the density of bright and dark bodies is 2.7 and 1.3 g/cm3, respectively, we estimate that the Earth should undergo a 1000 megatons collision every 64,000 years. Based on our model, we have computed the expected NEO distribution in the sky to- gether with their apparent magnitudes and rates of motion. This is the basis to simulate the efficiency of the various survey strategies. To understand the detection efficiency of various survey strategies, we have first simulated ``perfect surveys" as benchmarks. These are 100% efficient, all-sky, every night survey, subject only to the constraints of 1 detection above a specified air mass and when the Sun is below the horizon. We have computed that such a survey must have a limiting magnitude of about V=21 to reach 90% detection of NEOs with H<18 within ten years. Slightly more realistic surveys, limited by latitude, the galaxy, minimum rates of NEO motion, etc, require progres- sively fainter limiting magnitude to reach the 90% completion level. A survey with the sky-coverage of LINEAR could detect 90% of the NEOs with H<18 only if its limiting magnitude is 24 (the current 50% efficiency magnitude of LINEAR is around 18.5). Our simulations suggest that there may be little need for distributing survey telescopes in longitude and latitude as long as there is sufficient sky coverage from a telescope or network of telescopes which may be geographically close. Conversely, a space based survey, especially from a satellite orbit much interior to Earth, offers a tremendous advantage over their terrestrial planted brethren. For instance, a perfect survey based at Mercury with limiting magnitude V=18 would discover 90% of the NEOs with H<18 in less than 4 years. 2 </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active">6</li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_7" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active">7</li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="121"> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhDT........92C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhDT........92C">A feasibility study on the implementation of satellite-to-satellite tracking around a small near-Earth object</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Church, Christopher J. Near-earth objects (NEOs) are asteroids and comets that have a perihelion distance of less than 1.3 astronomical units (AU). There are currently more than 10,000 known NEOs. The majority of these objects are less than 1 km in diameter. Despite the number of NEOs, little is known about most of them. Characterizing these objects is a crucial component in developing a thorough understanding of solar system evolution, human exploration, exploitation of asteroid resources, and threat mitigation. Of particular interest is characterizing the internal structure of NEOs. While ground-based methods exist for characterizing the internal structure of NEOs, the information that can be gleaned from such studies is limited and often accompanied by large uncertainty. An alternative is to use in situ studies to examine an NEO's shape and gravity field, which can be used to assess its internal structure. This thesis investigates the use of satellite-to-satellite tracking (SST) to map the gravity field of a small NEO on the order of 500 m or less. An analysis of the mission requirements of two previously flown SST missions, GRACE and GRAIL, is conducted. Additionally, a simulation is developed to investigate the dynamics of SST in the vicinity of a small NEO. This simulation is then used to simulate range and range-rate data in the strongly perturbed environment of the small NEO. These data are used in conjunction with the analysis of the GRACE and GRAIL missions to establish a range of orbital parameters that can be used to execute a SST mission around a small NEO. Preliminary mission requirements for data collection and orbital correction maneuvers are also established. Additionally, the data are used to determine whether or not proven technology can be used to resolve the expected range and range-rate measurements. It is determined that the orbit semi-major axis for each spacecraft should be approximately 100% to 200% of the NEO's mean diameter and the two spacecraft should be in circular, near polar orbits. This configuration will produce trajectories, which exhibit reasonable stability over a period of roughly 24 hours. Corrective maneuvers will therefore be required with a frequency of approximately once per day. Due to the potentially rapid changes caused by the highly perturbed environment, it is likely that these maneuvers will need to be made autonomously. During the period between corrective maneuvers SST data collection will be possible. The expected range and range-rate measurements will be on the order of +/-10-5 m and +/-10 -5 m/s respectively and can be resolved using proven technology. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/22663137-neowise-reactivation-mission-year-three-asteroid-diameters-albedos','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22663137-neowise-reactivation-mission-year-three-asteroid-diameters-albedos">NEOWISE Reactivation Mission Year Three: Asteroid Diameters and Albedos</a> <a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Masiero, Joseph R.; Mainzer, A. K.; Kramer, E. The Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) reactivation mission has completed its third year of surveying the sky in the thermal infrared for near-Earth asteroids and comets. NEOWISE collects simultaneous observations at 3.4 and 4.6 μ m of solar system objects passing through its field of regard. These data allow for the determination of total thermal emission from bodies in the inner solar system, and thus the sizes of these objects. In this paper, we present thermal model fits of asteroid diameters for 170 NEOs and 6110 Main Belt asteroids (MBAs) detected during the third year of the survey,more » as well as the associated optical geometric albedos. We compare our results with previous thermal model results from NEOWISE for overlapping sample sets, as well as diameters determined through other independent methods, and find that our diameter measurements for NEOs agree to within 26% (1 σ ) of previously measured values. Diameters for the MBAs are within 17% (1 σ ). This brings the total number of unique near-Earth objects characterized by the NEOWISE survey to 541, surpassing the number observed during the fully cryogenic mission in 2010.« less </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IAUGA..2250930T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IAUGA..2250930T">KLENOT Project - Near Earth Objects Follow-up Program</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Tichy, Milos; Ticha, Jana; Kocer, Michal; Tichy, Milos 2015-08-01 Near Earth Object (NEO) research is important not only as a great challenge for science but also as an important challenge for planetary defense. Therefore NEO discoveries, astrometric follow-up, orbit computations as well as physical studies are of high interest both to science community and humankind.The KLENOT Project of the Klet Observatory, South Bohemia, Czech Republic pursued the confirmation, early follow-up, long-arc follow-up and recovery of NEOs since 2002. Tens of thousands astrometric measurements helped to make inventory of NEOs as well as to understand the NEO distribution. It ranked among the world most prolific professional NEO follow-up programmes during its first phase from 2002 to 2008.The fundamental improvement of the 1.06-m KLENOT Telescope was started in autumn 2008. The new computer controlled paralactic mount was built to substantially increase telescope-time efficiency, the number of observations, their accuracy and limiting magnitude. The testing observations of the KLENOT Telescope Next Generation were started in October 2011. The new more efficient CCD camera FLI ProLine 230 was installed in summer 2013.The original Klet Software Package has been continually upgraded over the past two decades of operation.Both the system and strategy for the NEO follow-up observation used in the framework of the KLENOT Project are described here, including methods for selecting useful and important targets for NEO follow-up astrometry.The modernized KLENOT System was put into full operation in September 2013. More than 8000 of minor planet and comet astrometric positions including NEA measurements were published from September 2013 to February 2015.The 1.06-m KLENOT telescope is still the largest telescope in continental Europe used exclusively for observations of asteroids and comets. Full observing time is dedicated to the KLENOT team. Considering our results and long-time experience obtained at the Klet Observatory, we have the large potential to contribute to recent NEO efforts.Since October 2014 the KLENOT Project has been a part of European Space Agency Space Systém Awareness Programme (ESA-SSA) - NEO Segment - Cooperating Sensors. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4851602M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4851602M">NEOs in the mid-infrared: from Spitzer to JWST</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Mueller, Michael; Thomas, Cristina A. 2016-10-01 Near-Earth Objects (NEOs) account for a surprisingly large fraction of the Spitzer observing time devoted to Solar System science. As a community, we should think of ways to repeat that success with JWST. JWST is planning an open Early Release Science Program, with the expected deadline for letters of intent in early 2017. We can't wait for next year's DPS to develop ideas. The time is now!In order to stir up the discussion, we will present ideas for NEO observing programs that are well adapted to JWST's capabilities and limitations, based on our recent PASP paper (Thomas et al., 2016). Obvious measurement objectives would include* size and albedo from thermal continuum (MIRI photometry)* thermal inertia for objects with well-known shape and spin state (MIRI)* taxonomy through reflection spectroscopy and emission spectroscopy in the NIR and MIR; NIR colors for faint objects.In all cases, JWST's sensitivity will allow us to go deeper than currently possible by at least an order of magnitude. Meter-sized NEOs similar to 2009 BD or 2011 MD are easy targets for MIRI spectrophotometry!The following limitations must be kept in mind, however: JWST's large size makes it slow to move. Most problematic for NEOs is probably the resulting 'speed limit': non-sidereal tracking is supported up to a rate of 30 mas/s, NEOs can easily move faster than that (ways to relax this constraint are under discussion). The average slew to a new target is budgeted to take 30 min, effectively ruling out programs many-target programs like ExploreNEOs or NEOSurvey (see D. Trilling's paper). Additionally, JWST will only observe close to quadrature, translating to large solar phase angles for NEO observations; this is familiar from other space-based IR facilities. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AJ....154...13V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AJ....154...13V">Near-Earth Object Orbit Linking with the Large Synoptic Survey Telescope</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Vereš, Peter; Chesley, Steven R. 2017-07-01 We have conducted a detailed simulation of the ability of the Large Synoptic Survey Telescope (LSST) to link near-Earth and main belt asteroid detections into orbits. The key elements of the study were a high-fidelity detection model and the presence of false detections in the form of both statistical noise and difference image artifacts. We employed the Moving Object Processing System (MOPS) to generate tracklets, tracks, and orbits with a realistic detection density for one month of the LSST survey. The main goals of the study were to understand whether (a) the linking of near-Earth objects (NEOs) into orbits can succeed in a realistic survey, (b) the number of false tracks and orbits will be manageable, and (c) the accuracy of linked orbits would be sufficient for automated processing of discoveries and attributions. We found that the overall density of asteroids was more than 5000 per LSST field near opposition on the ecliptic, plus up to 3000 false detections per field in good seeing. We achieved 93.6% NEO linking efficiency for H< 22 on tracks composed of tracklets from at least three distinct nights within a 12 day interval. The derived NEO catalog was comprised of 96% correct linkages. Less than 0.1% of orbits included false detections, and the remainder of false linkages stemmed from main belt confusion, which was an artifact of the short time span of the simulation. The MOPS linking efficiency can be improved by refined attribution of detections to known objects and by improved tuning of the internal kd-tree linking algorithms. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120003234','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120003234">Finding Near-Earth Asteroid (NEA) Destinations for Human Exploration: Implications for Astrobiology</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Landis, Rob; Abell, Paul; Barbee, Brent; Johnson, Lindley 2012-01-01 The current number of known potential NEA targets for HSF is limited to those objects whose orbital characteristics are similar to that of the Earth. This is due to the projected capabilities of the exploration systems currently under consideration and development at NASA. However, NEAs with such orbital characteristics often have viewing geometries that place them at low solar elongations and thus are difficult to detect from the vicinity of Earth. While ongoing ground-based surveys and data archives maintained by the NEO Program Observation Program Office and the Minor Planet Center (MPC) have provided a solid basis upon which to build, a more complete catalog of the NEO population is required to inform a robust and sustainable HSF exploration program. Since all the present NEO observing assets are currently confined to the vicinity of the Earth, additional effort must be made to provide capabilities for detection of additional HSF targets via assets beyond Earth orbit. A space-based NEO survey telescope located beyond the vicinity of the Earth, has considerable implications for planetary science and astrobiology. Such a telescope will provide foundational knowledge of our Solar System small body population and detect targets of interest for both the HSF and scientific communities. Data from this asset will yield basic characterization data on the NEOs observed (i.e., albedo, size determination, potential for volatiles and organics, etc.) and help down select targets for future HSF missions. Ideally, the most attractive targets from both HSF and astrobiology perspectives are those NEAs that may contain organic and volatile materials, and which could be effectively sampled at a variety of locations and depths. Presented here is an overview of four space-based survey concepts; any one of which after just a few years of operation will discover many highly accessible NEO targets suitable for robotic and human exploration. Such a space-based survey mission will reveal incredible returns for several disciplines including: exploration, in situ resource utilization, planetary defense, and science. Of particular, interest to the scientific </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014Icar..228..217T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014Icar..228..217T">Physical characterization of Warm Spitzer-observed near-Earth objects</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Thomas, Cristina A.; Emery, Joshua P.; Trilling, David E.; Delbó, Marco; Hora, Joseph L.; Mueller, Michael 2014-01-01 Near-infrared spectroscopy of Near-Earth Objects (NEOs) connects diagnostic spectral features to specific surface mineralogies. The combination of spectroscopy with albedos and diameters derived from thermal infrared observations can increase the scientific return beyond that of the individual datasets. For instance, some taxonomic classes can be separated into distinct compositional groupings with albedo and different mineralogies with similar albedos can be distinguished with spectroscopy. To that end, we have completed a spectroscopic observing campaign to complement the ExploreNEOs Warm Spitzer program that obtained albedos and diameters of nearly 600 NEOs (Trilling, D.E. et al. [2010]. Astron. J. 140, 770-784. http://dx.doi.org/10.1088/0004-6256/140/3/770). The spectroscopy campaign included visible and near-infrared observations of ExploreNEOs targets from various observatories. Here we present the results of observations using the low-resolution prism mode (˜0.7-2.5 μm) of the SpeX instrument on the NASA Infrared Telescope Facility (IRTF). We also include near-infrared observations of ExploreNEOs targets from the MIT-UH-IRTF Joint Campaign for Spectral Reconnaissance. Our dataset includes near-infrared spectra of 187 ExploreNEOs targets (125 observations of 92 objects from our survey and 213 observations of 154 objects from the MIT survey). We identify a taxonomic class for each spectrum and use band parameter analysis to investigate the mineralogies for the S-, Q-, and V-complex objects. Our analysis suggests that for spectra that contain near-infrared data but lack the visible wavelength region, the Bus-DeMeo system misidentifies some S-types as Q-types. We find no correlation between spectral band parameters and ExploreNEOs albedos and diameters. We investigate the correlations of phase angle with Band Area Ratio and near-infrared spectral slope. We find slightly negative Band Area Ratio (BAR) correlations with phase angle for Eros and Ivar, but a positive BAR correlation with phase angle for Ganymed. The results of our phase angle study are consistent with those of (Sanchez, J.A., Reddy, V., Nathues, A., Cloutis, E.A., Mann, P., Hiesinger, H. [2012]. Icarus 220, 36-50. http://dx.doi.org/10.1016/j.icarus.2012.04.008, arXiv:1205.0248). We find evidence for spectral phase reddening for Eros, Ganymed, and Ivar. We identify the likely ordinary chondrite type analog for an appropriate subset of our sample. Our resulting proportions of H, L, and LL ordinary chondrites differ from those calculated for meteorite falls and in previous studies of ordinary chondrite-like NEOs. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018sptz.prop14004T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018sptz.prop14004T">Physical characterization of Near Earth Objects with Spitzer</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Trilling, David; Hora, Joseph; Mommert, Michael; Chesley, Steve; Emery, Joshua; Fazio, Giovanni; Harris, Alan; Mueller, Migo; Smith, Howard 2018-05-01 We propose here an efficient, flux-limited survey of 426 optically discovered NEOs in order to measure their diameters and albedos. We include only targets not previously detected by Spitzer or NEOWISE and includes all NEOs available to Spitzer in Cycle 14. This program will maintain the fraction of all known NEOs with measured diameters and albedos at around 20% even in the face of increasingly successful NEO discovery surveys. By the conclusion of this program nearly 3500 NEOs will have measured diameters and albedos, with nearly 3000 of those observations being made by Spitzer and our team. We will determine an independent size distribution of NEOs at 100 meters that is free from albedo assumptions, addressing a current controversy. We will also derive, through our albedo measurements, the compositional distribution of NEOs as a function of size. We will measure or constrain lightcurves for more than 400 NEOs, thus constraining their shapes in addition to sizes and compositions. This catalog will enable a number of other science cases to be pursued by us and other researchers. Our team has unmatched experience observing NEOs with Spitzer. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009ExA....23..785B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009ExA....23..785B">MARCO POLO: near earth object sample return mission</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Barucci, M. A.; Yoshikawa, M.; Michel, P.; Kawagushi, J.; Yano, H.; Brucato, J. R.; Franchi, I. A.; Dotto, E.; Fulchignoni, M.; Ulamec, S. 2009-03-01 MARCO POLO is a joint European-Japanese sample return mission to a Near-Earth Object. This Euro-Asian mission will go to a primitive Near-Earth Object (NEO), which we anticipate will contain primitive materials without any known meteorite analogue, scientifically characterize it at multiple scales, and bring samples back to Earth for detailed scientific investigation. Small bodies, as primitive leftover building blocks of the Solar System formation process, offer important clues to the chemical mixture from which the planets formed some 4.6 billion years ago. Current exobiological scenarios for the origin of Life invoke an exogenous delivery of organic matter to the early Earth: it has been proposed that primitive bodies could have brought these complex organic molecules capable of triggering the pre-biotic synthesis of biochemical compounds. Moreover, collisions of NEOs with the Earth pose a finite hazard to life. For all these reasons, the exploration of such objects is particularly interesting and urgent. The scientific objectives of MARCO POLO will therefore contribute to a better understanding of the origin and evolution of the Solar System, the Earth, and possibly Life itself. Moreover, MARCO POLO provides important information on the volatile-rich (e.g. water) nature of primitive NEOs, which may be particularly important for future space resource utilization as well as providing critical information for the security of Earth. MARCO POLO is a proposal offering several options, leading to great flexibility in the actual implementation. The baseline mission scenario is based on a launch with a Soyuz-type launcher and consists of a Mother Spacecraft (MSC) carrying a possible Lander named SIFNOS, small hoppers, sampling devices, a re-entry capsule and scientific payloads. The MSC leaves Earth orbit, cruises toward the target with ion engines, rendezvous with the target, conducts a global characterization of the target to select a sampling site, and delivers small hoppers (MINERVA type, JAXA) and SIFNOS. The latter, if added, will perform a soft landing, anchor to the target surface, and make various in situ measurements of surface/subsurface materials near the sampling site. Two surface samples will be collected by the MSC using “touch and go” manoeuvres. Two complementary sample collection devices will be used in this phase: one developed by ESA and another provided by JAXA, mounted on a retractable extension arm. After the completion of the sampling and ascent of the MSC, the arm will be retracted to transfer the sample containers into the MSC. The MSC will then make its journey back to Earth and release the re-entry capsule into the Earth’s atmosphere. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014acm..conf..320L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014acm..conf..320L">The LCOGT near-Earth-object follow-up network</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Lister, T. 2014-07-01 Las Cumbres Observatory Global Telescope (LCOGT) network is a planned homogeneous network that will eventually consist of over 35 telescopes at 6 locations in the northern and southern hemispheres [1]. This network is versatile and designed to respond rapidly to target of opportunity events and also to do long term monitoring of slowly changing astronomical phenomena. The global coverage of the network and the apertures of telescope available make the LCOGT network ideal for follow-up and characterization of a wide range of solar-system objects (e.g. asteroids, Kuiper-belt objects, comets) and in particular near-Earth objects (NEOs). There are 3 classes to the telescope resources: 2-meter aperture, 1-meter aperture and 0.4-meter aperture. We have been operating our two 2-meter telescopes since 2005 and began a specific program of NEO follow-up for the Pan-STARRS survey in October 2010. The combination of all-sky access, large aperture, rapid response, robotic operation and good site conditions allows us to provide time-critical follow-up astrometry and photometry on newly discovered objects and faint objects as they recede from the Earth, allowing the orbital arc to be extended and preventing loss of objects. These telescope resources have greatly increased as LCOGT has completed the first phase of the deployment, designated as ''Version 1.0'', with the installation, commissioning and ongoing operation of nine 1-meter telescopes. These are distributed among four sites with one 1-meter at McDonald Observatory (Texas), three telescopes at Cerro Tololo (Chile), three telescopes at SAAO (South Africa) and the final two telescope at Siding Spring Observatory (Australia). In addition to the 1-meter network, the scheduling and control system for the two 2-meter telescopes have been upgraded and unified with that of the 1-meter network to provide a coherent robotic telescopic network. The telescope network is now operating and observations are being executed remotely and robotically. I am using the LCOGT network to confirm newly detected NEO candidates produced by the major sky surveys such as Catalina Sky Survey (CSS) and Pan-STARRS (PS1) with additional targets coming from the NEOWISE satellite and the Palomar Transient Factory (PTF). Robotic observations of NEOs and other solar-system objects have been routinely carried out for several years on the 2-m and 1-m telescopes, with over 20,000 positional and magnitude measurements reported to the Minor Planet Center (MPC) in the last two years. We have developed software to automatically fetch candidates from Pan-STARRS and the MPC Confirmation Page, compute orbits and ephemerides, plan and schedule observations on the telescopes and retrieve the processed data [2]. The program is being expanded which will allow us to greatly increase the amount of survey discoveries that are followed-up, obtain accurate astrometry and provide important characterization data in the form of colors, lightcurves, rotation rates and spectra for NEOs. An increasing amount of time is being spent to obtain follow-up astrometry and photometry for radar-targeted objects in order to improve the orbits and determine the rotation periods. Priority for follow-up is now given to the fainter and most southern targets on the Confirmation Page, objects that are scheduled for Goldstone/Arecibo radar targeting and those objects which could become potential mission destinations for spacecraft. This will be extended to obtain more light curves of other NEOs which could be Near-Earth Object Human Space Flight Accessible Targets Study (NHATS) or Asteroid Retrieval Mission (ARM) targets. With the increase in time available from the LCOGT 1-meter network and commissioning of low-resolution spectrographs on the 2-meter telescopes for moving objects, this will produce a large advance in capabilities for NEO follow-up and characterization. This will produce an unprecedented network for NEO follow-up, particularly in the Southern Hemisphere where there is currently a shortage of suitable facilities. We will continue to develop our software to take advantage of the increased resources and capabilities of the LCOGT Network. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EPSC...11..435I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EPSC...11..435I">A photometric survey of Near-Earth Objects in support of the NEOShield-2 project</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Ieva, S.; Dotto, E.; Mazzotta Epifani, E.; Perna, D.; Barucci, M. A.; Di Paola, A.; Micheli, M.; Perozzi, E.; Speziali, R.; Lazzarin, M.; Bertini, I.; Giunta, A.; Lazzaro, D.; Arcoverde, P. 2017-09-01 More than 85% of the 16,000 NEOs discovered up to now lack a physical characterization. The study of their physical properties is essential to define a proper mitigation scenario. One of the main aims of the NEOShield-2 project (2015-2017), financed by the European Community in the framework of the Horizon 2020 program, is therefore to retrieve physical properties of a wide number of NEOs, in order to design impact mitigation missions and assess the consequences of an impact on Earth. We present the results obtained during a 2-year Long-Term Program at the Telescopio Nazionale Galileo (TNG, La Palma, Spain), where we carried out BVRI photometry of about 150 NEOs, and the analysis of the phase curves obtained at the Campo Imperatore telescope (L'Aquila, Italy) and the Observatório Astronômico do Sertão de Itaparica (Nova Itacuruba, Brazil). </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009PhDT.........9T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009PhDT.........9T">Tracing meteorite source regions through asteroid spectroscopy</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Thomas, Cristina Ana By virtue of their landing on Earth, meteorites reside in near-Earth object (NEO) orbits prior to their arrival. Thus the population of observable NEOs, in principle, gives the best representation of meteorite source bodies. By linking meteorites to NEOs, and linking NEOs to their most likely main-belt source locations, we seek to gain insight into the original solar system formation locations for different meteorite classes. To forge the first link between meteorites and NEOs, we have developed a three dimensional method for quantitative comparisons between laboratory measurements of meteorites and telescopic measurements of near-Earth objects. We utilize meteorite spectra from the Reflectance Experiment Laboratory (RELAB) database and NEO data from the SpeX instrument on the NASA Infrared Telescope Facility (IRTF). Using the Modified Gaussian Model (MGM) as a mathematical tool, we treat asteroid and meteorite spectra identically in the calculation of 1-micron and 2-micron geometric band centers and their band area ratios (BARs). Using these identical numerical parameters we quantitatively compare the spectral properties of S-, Sq-, Q- and V-type NEOs with the spectral properties of the meteorites in the H, L, LL and HED meteorite classes. For each NEO spectrum, we assign a set of probabilities for it being related to each of these meteorite classes. Our NEO- meteorite correlation probabilities are then convolved with NEO-source region probabilities to yield a final set of meteorite-source region correlations. An apparent (significant at the 2.1-sigma level) source region signature is found for the H chondrites to be preferentially delivered to the inner solar system through the 3:1 mean motion resonance. A 3:1 resonance H chondrite source region is consistent with the short cosmic ray exposure ages known for H chondrites. The spectroscopy of asteroids is subject to several sources of inherent error. The source region model used a variety of S-type spectra without attempting to infer mineralogy. Yet work by Gaffey et al. (1993) describes the S-asteroid class as home to a wide variety of mineralogies. Using data from the Small Main-belt Asteroid Spectroscopic Survey (SMASS), the 24-color asteroid survey and the 52-color asteroid survey, the spectral parameters of subclass members are investigated to predict possible errors to our model. While spectra are a diagnostic tool, there are factors inherent to the environment of near-Earth asteroids that pose ambiguities, such as grain size, temperature and space weathering. These factors are difficult to deconvolve from the compositional signal and are addressed here by simulated effects on meteorites from RELAB, Moroz et al. (2000) and Strazzulla et al (2005). A long-standing puzzle in asteroid science is the space weathering process and its implications for the relationship between S-type asteroids and ordinary chondrites. While Q-type asteroids are most spectrally similar to ordinary chondrites, these meteorites share certain diagnostic similarities with S-type asteroids. Binzel et al. (2004) statistically demonstrated a trend in spectral slope in near-Earth objects from 0.1 to 5 km. This analysis provided a missing link between the Q- and S-type by showing a reddening of spectral slope with larger diameter that corresponds to a transition from Q-type asteroid spectra to S-type asteroid spectra. This reddening of spectral slope is attributed to the effects of space weathering on the observable surface composition. This work shows preliminary results of a photometric survey of small Koronis family members. Observations of these objects were obtained in visible and near- infrared Harris and Sloan filters. Due to their common origin, Koronis family members have shown similar S-type spectroscopic signatures. We assume this consistency applies to the small-unclassified bodies. This provides a unique opportunity to compare the effects of the space weathering process on potentially ordinary chondrite-like bodies within a population of identical initial conditions. By examining a size range similar to the Binzel et al. work we hope to compare the slope reddening transition sizes within the near-Earth population and the main-belt. This data set should prove crucial to our understanding of the space weathering process and its relevant timescales. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.) </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AcAau.103..362L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AcAau.103..362L">A decision analysis approach for risk management of near-earth objects</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Lee, Robert C.; Jones, Thomas D.; Chapman, Clark R. 2014-10-01 Risk management of near-Earth objects (NEOs; e.g., asteroids and comets) that can potentially impact Earth is an important issue that took on added urgency with the Chelyabinsk event of February 2013. Thousands of NEOs large enough to cause substantial damage are known to exist, although only a small fraction of these have the potential to impact Earth in the next few centuries. The probability and location of a NEO impact are subject to complex physics and great uncertainty, and consequences can range from minimal to devastating, depending upon the size of the NEO and location of impact. Deflecting a potential NEO impactor would be complex and expensive, and inter-agency and international cooperation would be necessary. Such deflection campaigns may be risky in themselves, and mission failure may result in unintended consequences. The benefits, risks, and costs of different potential NEO risk management strategies have not been compared in a systematic fashion. We present a decision analysis framework addressing this hazard. Decision analysis is the science of informing difficult decisions. It is inherently multi-disciplinary, especially with regard to managing catastrophic risks. Note that risk analysis clarifies the nature and magnitude of risks, whereas decision analysis guides rational risk management. Decision analysis can be used to inform strategic, policy, or resource allocation decisions. First, a problem is defined, including the decision situation and context. Second, objectives are defined, based upon what the different decision-makers and stakeholders (i.e., participants in the decision) value as important. Third, quantitative measures or scales for the objectives are determined. Fourth, alternative choices or strategies are defined. Fifth, the problem is then quantitatively modeled, including probabilistic risk analysis, and the alternatives are ranked in terms of how well they satisfy the objectives. Sixth, sensitivity analyses are performed in order to examine the impact of uncertainties. Finally, the need for further analysis, data collection, or refinement is determined. The first steps of defining the problem and the objectives are critical to constructing an informative decision analysis. Such steps must be undertaken with participation from experts, decision-makers, and stakeholders (defined here as "decision participants"). The basic problem here can be framed as: “What is the best strategy to manage risk associated with NEOs?” Some high-level objectives might be to minimize: mortality and injuries, damage to critical infrastructure (e.g., power, communications and food distribution), ecosystem damage, property damage, ungrounded media and public speculation, resources expended, and overall cost. Another valuable objective would be to maximize inter-agency/government coordination. Some of these objectives (e.g., “minimize mortality”) are readily quantified (e.g., deaths and injuries averted). Others are less so (e.g., “maximize inter-agency/government coordination”), but these can be scaled. Objectives may be inversely related: e.g., a strategy that minimizes mortality may cost more. They are also unlikely to be weighted equally. Defining objectives and assessing their relative weight and interactions requires early engagement with decision participants. High-level decisions include whether to deflect a NEO, when to deflect, what is the best alternative for deflection/destruction, and disaster management strategies if an impact occurs. Important influences include, for example: NEO characteristics (orbital characteristics, diameter, mass, spin and composition), impact probability and location, interval between discovery and projected impact date, interval between discovery and deflection target date, costs of information collection, costs and technological feasibility of deflection alternatives, risks of deflection campaigns, requirements for inter-agency and international cooperation, and timing of informing the public. The analytical aspects of decision analysis center on estimation of the expected value (i.e. utility) of different alternatives. The expected value of an alternative is a function of the probability-weighted consequences, estimated using Bayesian calculations in a decision tree or influence diagram model. The result is a set of expected-value estimates for all alternatives evaluated that enables a ranking; the higher the expected value, the more preferred the alternative. A common way to include resource limitations is by framing the decision analysis in the context of economics (e.g., cost-effectiveness analysis). An important aspect of decision analysis in the NEO risk management case is the ability, known as sensitivity analysis, to examine the effect of parameter uncertainty upon decisions. The simplest way to evaluate uncertainty associated with the information used in a decision analysis is to adjust the input values one at a time (or simultaneously) to examine how the results change. Monte Carlo simulations can be used to adjust the inputs over ranges or distributions of values; statistical means then are used to determine the most influential variables. These techniques yield a measure known as the expected value of imperfect information. This value is highly informative, because it allows the decision-maker with imperfect information to evaluate the impact of using experiments, tests, or data collection (e.g. Earth-based observations, space-based remote sensing, etc.) to refine judgments; and indeed to estimate how much should be spent to reduce uncertainty. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009P%26SS...57..384P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009P%26SS...57..384P">Space weathering on near-Earth objects investigated by neutral-particle detection</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Plainaki, C.; Milillo, A.; Orsini, S.; Mura, A.; De Angelis, E.; Di Lellis, A. M.; Dotto, E.; Livi, S.; Mangano, V.; Massetti, S.; Palumbo, M. E. 2009-03-01 The ion-sputtering (IS) process is active in many planetary environments in the solar system where plasma precipitates directly on the surface (for instance, Mercury, Moon and Europa). In particular, solar wind sputtering is one of the most important agents for the surface erosion of a near-Earth object (NEO), acting together with other surface release processes, such as photon stimulated desorption (PSD), thermal desorption (TD) and micrometeoroid impact vaporization (MIV). The energy distribution of the IS-released neutrals peaks at a few eVs and extends up to hundreds of eVs. Since all other release processes produce particles of lower energies, the presence of neutral atoms in the energy range above 10 eV and below a few keVs (sputtered high-energy atoms (SHEA)) identifies the IS process. SHEA easily escape from the NEO, due to NEO's extremely weak gravity. Detection and analysis of SHEA will give important information on surface-loss processes as well as on surface elemental composition. The investigation of the active release processes, as a function of the external conditions and the NEO surface properties, is crucial for obtaining a clear view of the body's present loss rate as well as for getting clues on its evolution, which depends significantly on space weather. In this work, an attempt to analyze processes that take place on the surface of these small airless bodies, as a result of their exposure to the space environment, has been realized. For this reason, a new space weathering model (space weathering on NEO-SPAWN) is presented. Moreover, an instrument concept of a neutral-particle analyzer specifically designed for the measurement of neutral density and the detection of SHEA from a NEO is proposed. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..1112066P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..1112066P">Space weathering on near-Earth objects investigated by neutral-particle detection</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Plainaki, C.; Milillo, A.; Orsini, S.; Mura, A.; de Angelis, E.; di Lellis, A. M.; Dotto, E.; Livi, S.; Mangano, V.; Palumbo, M. E. 2009-04-01 The ion-sputtering (IS) process is active in many planetary environments in the solar system where plasma precipitates directly on the surface (for instance, Mercury, Moon and Europa). In particular, solar wind sputtering is one of the most important agents for the surface erosion of a near-Earth object (NEO), acting together with other surface release processes, such as photon stimulated desorption (PSD), thermal desorption (TD) and micrometeoroid impact vaporization (MIV). The energy distribution of the IS-released neutrals peaks at a few eVs and extends up to hundreds of eVs. Since all other release processes produce particles of lower energies, the presence of neutral atoms in the energy range above 10 eV and below a few keVs (sputtered high-energy atoms (SHEA)) identifies the IS process. SHEA easily escape from the NEO, due to NEO's extremely weak gravity. Detection and analysis of SHEA will give important information on surface-loss processes as well as on surface elemental composition. The investigation of the active release processes, as a function of the external conditions and the NEO surface properties, is crucial for obtaining a clear view of the body's present loss rate as well as for getting clues on its evolution, which depends significantly on space weather. In this work, an attempt to analyze processes that take place on the surface of these small airless bodies, as a result of their exposure to the space environment, has been realized. For this reason, a new space weathering model (space weathering on NEO-SPAWN) is presented. Moreover, an instrument concept of a neutral-particle analyzer specifically designed for the measurement of neutral density and the detection of SHEA from a NEO is proposed. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013suba.prop...54K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013suba.prop...54K">Search for Dormant Comets in Near-Earth Space</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Kim, Yoonyoung 2013-06-01 It is considered that comets have been injected into near-Earth space from outer region (e.g. Kuiper-belt region), providing rich volatile and organic compounds to the earth. Some comets are still active while most of them are dormant with no detectable tails and comae. Here we propose to make a multi-band photometric observation of near-Earth objects (NEOs) with comet-like orbits. We select our targets out of infrared asteroidal catalogs based on AKARI and WISE observations. With a combination of taxonomic types by Subaru observation and albedos by AKARI or WISE, we aim to dig out dormant comet candidates among NEOs. Our results will provide valuable information to figure out the dynamical evolution and fate of comets. We would like to emphasize that this is the first taxonomic survey of dormant comets to utilize the infrared data archive with AKARI and WISE. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20060031565&hterms=quantifying+risk&qs=N%3D0%26Ntk%3DTitle%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dquantifying%2Brisk','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20060031565&hterms=quantifying+risk&qs=N%3D0%26Ntk%3DTitle%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dquantifying%2Brisk">Quantifying the risk posed by potential Earth impacts</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Chesley, S. R.; Chodas, P. W.; Harris, A. W.; Milani, A.; Valsecchi, G. B.; Yeomans, D. K. 2001-01-01 Predictions of future potential Earth impacts by near-Earth objects (NEOs) have become commonplace in recent years, and the rate of these detections is likely to accelerate as asteroid survey efforts continue to mature. In this paper we describe the metrics introduced, and we give numerous examples of their application. This enables us to establish in rough terms the levels at which events become interesting to various parties. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...818L..29Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...818L..29Y">Comet 252P/LINEAR: Born (Almost) Dead?</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Ye, Quan-Zhi; Brown, Peter G.; Wiegert, Paul A. 2016-02-01 Previous studies have revealed Jupiter-family comet 252P/LINEAR as a comet that was recently transported into the near-Earth object (NEO) region in ∼1800 AD yet only being weakly active. In this Letter, we examine the “formed (almost) dead” hypothesis for 252P/LINEAR using both dynamical and observational approaches. By statistically examining the dynamical evolution of 252P/LINEAR over a period of 107 years, we find the median elapsed residency in the NEO region to be 4 × 102 years, which highlights the likelihood of 252P/LINEAR as an (almost) first-time NEO. With available cometary and meteor observations, we find the dust production rate of 252P/LINEAR to be on the order of 106 kg per orbit since its entry to the NEO region. These two lines of evidence support the hypothesis that the comet was likely to have formed in a volatile-poor environment. Cometary and meteor observations during the comet's unprecedented close approach to the Earth around 2016 March 21 would be useful for understanding of the surface and evolutionary properties of this unique comet. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150011453','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150011453">An Innovative Solution to NASA's NEO Impact Threat Mitigation Grand Challenge and Flight Validation Mission Architecture Development</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Wie, Bong; Barbee, Brent W. 2015-01-01 This paper presents the results of a NASA Innovative Advanced Concept (NIAC) Phase 2 study entitled "An Innovative Solution to NASA's Near-Earth Object (NEO) Impact Threat Mitigation Grand Challenge and Flight Validation Mission Architecture Development." This NIAC Phase 2 study was conducted at the Asteroid Deflection Research Center (ADRC) of Iowa State University in 2012-2014. The study objective was to develop an innovative yet practically implementable mitigation strategy for the most probable impact threat of an asteroid or comet with short warning time (< 5 years). The mitigation strategy described in this paper is intended to optimally reduce the severity and catastrophic damage of the NEO impact event, especially when we don't have sufficient warning times for non-disruptive deflection of a hazardous NEO. This paper provides an executive summary of the NIAC Phase 2 study results. Detailed technical descriptions of the study results are provided in a separate final technical report, which can be downloaded from the ADRC website (www.adrc.iastate.edu). </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.P13A1363K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.P13A1363K">Multiple NEO Rendezvous, Reconnaissance and In Situ Exploration</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Klaus, K.; Elsperman, M. S.; Cook, T.; Smith, D. 2010-12-01 We propose a two spacecraft mission (Mother Ship and Small Body Lander) rendezvous with multiple Near Earth Objects (NEO). This two spacecraft mission mimics the likely architecture approach that human explorers will use: a “mother ship”(MS) designed to get from Earth to the NEO and a “Small Body Lander”(SBL) that performs in situ investigation on or close to the NEO’s surface. The MS carries the SBL to the target NEO. Once at the target NEO, the MS conducts an initial reconnaissance in order to produce a high resolution map of the surface. This map is used to identify coordinates of interest which are sent to the SBL. The SBL un-docks from the MS to rendezvous with the NEO and collect data. Landings are possible, though the challenges of anchoring to the NEO surface are significant. The SBL design is flexible and adaptable, enabling science data collection on or near the surface. After surface investigations are completed on the first NEO, the SBL will return and autonomously rendezvous and dock with the MS. The MS then goes to the next NEO target. During transit to the next NEO, the SBL could be refueled by the MS, a TRL8 capability demonstrated on the DARPA/NASA Orbital Express mission in 2007, or alternately sized to operate without requiring refueling depending on the mission profile. The mission goals are to identify surface hazards; quantify engineering boundary conditions for future human visits, and identify resources for future exploitation. The mission goals will be accomplished through the execution of key mission objectives: (1) high-resolution surface topography; (2) surface composition and mineralogy; (3) radiation environment near NEO; and (4) mechanical properties of the surface. Essential SBL instruments include: a) LIDAR (Obj. 1); b) 3D, high- resolution hyperspectral imaging cameras (Obj. 2); c) radiation sensor package (Obj. 3); and d) strain gauges (Obj. 4). Additional or alternative instruments could include: e) x-ray fluorescence or laser-induced breakdown spectroscopy (LIBS) sensor package (Obj. 2); f) gamma ray/neutron spectrometry package (Obj. 2); and g) radiometer package (to address variations in thermal environment). The ability to reach, survey, sample, and analyze multiple NEOs at close proximity is an enormous capability that can enable NASA to rapidly achieve the primary Exploration Precursor Robotic Mission (xPRM) Program goal of characterizing NEOs for future human exploration. Instead of launching multiple dedicated missions to each NEO of interest, a multi-NEO sortie mission can be planned and executed to achieve the same mission objectives with one launch, dramatically reducing the cost of NEO exploration. Collectively, our NEO Exploration System Architecture provides solutions for a wide variety of exploration activities using a common spacecraft bus and common core instrumentation for the spacecraft. This engineering consistency will substantially improve the probability of mission success, increase the likelihood of maintaining an aggressive launch schedule, and decrease the total cost of multiple missions. NASA successfully used this approach with the robotic precursors leading up to the Apollo missions, and we see significant benefits from this same programmatic approach for the xPRM program. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active">7</li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active">8</li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/22662922-neosurvey-initial-results-from-warm-spitzer-exploration-science-survey-near-earth-object-properties','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22662922-neosurvey-initial-results-from-warm-spitzer-exploration-science-survey-near-earth-object-properties">NEOSURVEY 1: INITIAL RESULTS FROM THE WARM SPITZER EXPLORATION SCIENCE SURVEY OF NEAR-EARTH OBJECT PROPERTIES</a> <a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Trilling, David E.; Mommert, Michael; Hora, Joseph Near-Earth objects (NEOs) are small solar system bodies whose orbits bring them close to the Earth’s orbit. We are carrying out a Warm Spitzer Cycle 11 Exploration Science program entitled NEOSurvey—a fast and efficient flux-limited survey of 597 known NEOs in which we derive a diameter and albedo for each target. The vast majority of our targets are too faint to be observed by NEOWISE, though a small sample has been or will be observed by both observatories, which allows for a cross-check of our mutual results. Our primary goal is to create a large and uniform catalog of NEO properties. Wemore » present here the first results from this new program: fluxes and derived diameters and albedos for 80 NEOs, together with a description of the overall program and approach, including several updates to our thermal model. The largest source of error in our diameter and albedo solutions, which derive from our single-band thermal emission measurements, is uncertainty in η , the beaming parameter used in our thermal modeling; for albedos, improvements in solar system absolute magnitudes would also help significantly. All data and derived diameters and albedos from this entire program are being posted on a publicly accessible Web page at nearearthobjects.nau.edu.« less </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070024872','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070024872">A Piloted Flight to a Near-Earth Object: A Feasibility Study</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Landis, Rob; Korsmeyer, Dave; Abell, Paul; Adamo, Dan; Morrison, Dave; Lu, Ed; Lemke, Larry; Gonzales, Andy; Jones, Tom; Gershman, Bob; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20070024872'); toggleEditAbsImage('author_20070024872_show'); toggleEditAbsImage('author_20070024872_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20070024872_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20070024872_hide"> 2007-01-01 This viewgraph presentation examines flight hardware elements of the Constellation Program (CxP) and the utilization of the Crew Exploration Vehicle (CEV), Evolvable Expendable Launch Vehicles (EELVs) and Ares launch vehicles for NEO missions. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150020912','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150020912">Near-Earth Asteroids 2006 RH120 And 2009 BD: Proxies For Maximally Accessible Objects?</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Barbee, Brent W.; Chodas, Paul W. 2015-01-01 Near-Earth Object Human Space Flight Accessible Targets Study(NHATS): http://neo.jpl.nasa.govnhats/. As of mid-July 2015: 1,434 of the 12,778 currently known NEAs are more astrodynamically accessible than is Mars (requiring less Delta v and or less flight time for round-trip missions). Within those 1,434 NEAs: 605 NEAs can be visited round-trip for less Delta v (9 km/s) than the lunar surface. 51 NEAs can be visited round-trip for less v (5 km/s) than low circular lunar orbit. NEO population statistical models:Tens of thousands of NEAs greater than 100 m yet to be discovered. At least several million NEAs less than or equal to100 m in size (down to approximately 3 m in size) yet to be discovered. How accessible are the NEAs that haven't yet been discovered? </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000P%26SS...48..801T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000P%26SS...48..801T">Space-based infrared near-Earth asteroid survey simulation</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Tedesco, Edward F.; Muinonen, Karri; Price, Stephan D. 2000-08-01 We demonstrate the efficiency and effectiveness of using a satellite-based sensor with visual and infrared focal plane arrays to search for that subclass of Near-Earth Objects (NEOs) with orbits largely interior to the Earth's orbit. A space-based visual-infrared system could detect approximately 97% of the Atens and 64% of the IEOs (the, as yet hypothetical, objects with orbits entirely Interior to Earth's Orbit) with diameters greater than 1 km in a 5-year mission and obtain orbits, albedos and diameters for all of them; the respective percentages with diameters greater than 500 m are 90% and 60%. Incidental to the search for Atens and IEOs, we found that 70% of all Earth-Crossing Asteroids (ECAs) with diameters greater than 1 km, and 50% of those with diameters greater than 500 m, would also be detected. These are the results of a feasibility study; optimizing the concept presented would result in greater levels of completion. The cost of such a space-based system is estimated to be within a factor of two of the cost of a ground-based system capable of about 21st magnitude, which would provide only orbits and absolute magnitudes and require decades to reach these completeness levels. In addition to obtaining albedos and diameters for the asteroids discovered in the space-based survey, a space-based visual-infrared system would obtain the same information on virtually all NEOs of interest. A combined space-based and ground-based survey would be highly synergistic in that each can concentrate on what it does best and each complements the strengths of the other. The ground-based system would discover the majority of Amors and Apollos and provide long-term follow-up on all the NEOs discovered in both surveys. The space-based system would discover the majority of Atens and IEOs and provide albedos and diameters on all the NEOs discovered in both surveys and most previously discovered NEOs as well. Thus, an integrated ground- and space-based system could accomplish the Spaceguard goal in less time than the ground-based system alone. In addition, the result would be a catalog containing well-determined orbits, diameters, and albedos for the majority of ECAs with diameters greater than 500 m. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AIPC.1278..502P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AIPC.1278..502P">Can Lasers Play a Rôle in Planetary Defense?</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Phipps, Claude 2010-10-01 It is now well-established that a Near-Earth Object (NEO) in the 5 to 10-km size range extinguished the dinosaurs. Although such events have an impact interval on the order of 100 M years, a method of rapid response to such a threat is crucial, since warning time is short. Objects in the 0.1 to 1 km size range may not be detected before approaching within 1 to 10 astronomical units (AU) of Earth and, since their approach velocity may be 30-60 km/s, that situation leaves 100-300 days to respond. Although the most frequently suggested response to such a threat is a standoff nuclear detonation, physically delivered to the NEO, this paper finds significant advantages in retargeting, probability of success and even precise target location are possible with a high power laser alternative. Assuming a momentum coupling coefficient Cm = 3.5 dyn-s/J and detection at 6.3 AU, a 770 kW repetitive pulse 355 nm laser (f = 1.7 ppm with 27 MJ, 10 ps pulses) will deflect a 200-m-diameter icy NEO sufficiently to avoid collision. The focusing mirror would need to be manufactured on the Moon. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Icar..265..209R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Icar..265..209R">The global impact distribution of Near-Earth objects</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Rumpf, Clemens; Lewis, Hugh G.; Atkinson, Peter M. 2016-02-01 Asteroids that could collide with the Earth are listed on the publicly available Near-Earth object (NEO) hazard web sites maintained by the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA). The impact probability distribution of 69 potentially threatening NEOs from these lists that produce 261 dynamically distinct impact instances, or Virtual Impactors (VIs), were calculated using the Asteroid Risk Mitigation and Optimization Research (ARMOR) tool in conjunction with OrbFit. ARMOR projected the impact probability of each VI onto the surface of the Earth as a spatial probability distribution. The projection considers orbit solution accuracy and the global impact probability. The method of ARMOR is introduced and the tool is validated against two asteroid-Earth collision cases with objects 2008 TC3 and 2014 AA. In the analysis, the natural distribution of impact corridors is contrasted against the impact probability distribution to evaluate the distributions' conformity with the uniform impact distribution assumption. The distribution of impact corridors is based on the NEO population and orbital mechanics. The analysis shows that the distribution of impact corridors matches the common assumption of uniform impact distribution and the result extends the evidence base for the uniform assumption from qualitative analysis of historic impact events into the future in a quantitative way. This finding is confirmed in a parallel analysis of impact points belonging to a synthetic population of 10,006 VIs. Taking into account the impact probabilities introduced significant variation into the results and the impact probability distribution, consequently, deviates markedly from uniformity. The concept of impact probabilities is a product of the asteroid observation and orbit determination technique and, thus, represents a man-made component that is largely disconnected from natural processes. It is important to consider impact probabilities because such information represents the best estimate of where an impact might occur. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140017387','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140017387">The Economics OF NEOS</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Schalkwyk, James D. 2014-01-01 NASA's Ames Research Center, in its role as partnerships lead for NASA asteroid redirect robotic missions and as a supporting Center for the Asteroid Grand Challenge, responded to increasing interest in near-Earth objects (NEOs) by holding a workshop entitled 'The Economics of NEOs' on the 6th and 7th of September 2014. The workshop was intended to serve as a catalyst for discussions and to foster collaborations between industry, academia and government. This document serves as a summary of the discussions which took place within three sessions and their respective table discussions; Session One: Background and Motivation; Session Two: Economics of NEOs; and Session Three: Policy and Legal Frameworks. This document is a collection of observations by individuals and does not express the consensus view of all participants; it does not express US Government or NASA policy. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20150006109&hterms=gpu&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dgpu','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20150006109&hterms=gpu&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dgpu">Granular Simulation of NEO Anchoring</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Mazhar, Hammad 2011-01-01 NASA is interested in designing a spacecraft capable of visiting a Near Earth Object (NEO), performing experiments, and then returning safely. Certain periods of this mission will require the spacecraft to remain stationary relative to the NEO. Such situations require an anchoring mechanism that is compact, easy to deploy and upon mission completion, easily removed. The design philosophy used in the project relies on the simulation capability of a multibody dynamics physics engine. On Earth it is difficult to create low gravity conditions and testing in low gravity environments, whether artificial or in space is costly and therefore not feasible. Through simulation, gravity can be controlled with great accuracy, making it ideally suited to analyze the problem at hand. Using Chrono::Engine [1], a simulation package capable of utilizing massively parallel GPU hardware, several validation experiments will be performed. Once there is sufficient confidence, modeling of the NEO regolith interaction will begin after which the anchor tests will be performed and analyzed. The outcome of this task is a study with an analysis of several different anchor designs, along with a recommendation on which anchor is better suited to the task of anchoring. With the anchors tested against a range of parameters relating to soil, environment and anchor penetration angles/velocities on a NEO. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010cosp...38.4261M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010cosp...38.4261M">The DLR AsteroidFinder for NEOs</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Mottola, Stefano; Kuehrt, Ekkehard; Michaelis, Harald; Hoffmann, Harald; Spietz, Peter; Jansen, Frank; Thimo Grundmann, Jan; Hahn, Gerhard; Montenegro, Sergio; Findlay, Ross; Boerner, Anko; Messina, Gabriele; Behnke, Thomas; Tschentscher, Matthias; Scheibe, Karsten; Mertens, Volker; Heidecke, Ansgar Potential Earth-impacting asteroids that spend most of their time interior to Earth's orbit are extremely difficult to be observed from the ground and remain largely undetected. Firstly, they are mostly located at small solar elongations, where the sky brightness and their faintness due to the large phase angle prevents their discovery. Secondly, these objects tend to have very long synodic orbital periods, which makes observation opportunities rare and impact warning times short. Because of these limitations, even the advent of next generation ground-based asteroid surveys is not likely to radically improve the situation (Veres et al. Icarus 203, p472, 2009). On the other hand, a small satellite with a suitable design can observe close to the Sun and detect these objects efficiently against a dark sky background. For this reason, DLR, the German Aerospace Center, has selected AsteroidFinder as the first experiment to be launched under its new compact satellite national program. The primary goal of the mission is to detect and characterize Near Earth Objects (NEOs), with a particular focus on the population of objects completely contained within Earth's orbit (IEOs or Inner Earth Objects). Current dynamical models predict the existence of more than 1000 such objects down to a size of 100m, of which, due to the abovementioned observation difficulties, only 10 have been discovered to date. Benefitting from the vantage point of a Low Earth Orbit (LEO), AsteroidFinder makes use of a small optical telescope to scan those regions of the sky that are close to the Sun, and therefore beyond the reach of ground based observatories. By estimating the population, the size and the orbital distribution of IEOs, AsteroidFinder will contribute to our knowledge of the inner Solar System, and to the assessment of the impact hazard for the Earth. A secondary goal of the mission is to demonstrate techniques that enable the space-based detection of space debris in the cm size range. With these mission goals, AsteroidFinder also addresses the programmatic goals of the ESA SSA initiative, both for the NEO and space debris domain. The AsteroidFinder mission is based on the DLR SSB standard platform, it employs a 400-cm2 clear-aperture, off-axis design telescope and an array of new technology CCDs. AsteroidFinder, which is presently in its Phase-B development stage, is planned to launch in 2013 with a one-year nominal mission duration and the possibility of an extension. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20030067577','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20030067577">Planetary Defense: Options for Deflection of Near Earth Objects</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Adams, R. B.; Statham, G.; Hopkins, R.; Chapman, J.; White, S.; Bonometti, J.; Alexander, R.; Fincher, S.; Polsgrove, T.; Kalkstein, M. 2003-01-01 Several recent near-miss encounters with asteroids and comets have focused attention on the threat of a catastrophic impact with the Earth. This document reviews the historical impact record and current understanding of the number and location of Near Earth Objects (NEO's) to address their impact probability. Various ongoing projects intended to survey and catalog the NEO population are also reviewed. Details are then given of an MSFC-led study, intended to develop and assess various candidate systems for protection of the Earth against NEOs. An existing program, used to model the NE0 threat, was extensively modified and is presented here. Details of various analytical tools, developed to evaluate the performance of proposed technologies for protection against the NEO threat, are also presented. Trajectory tools, developed to model the outbound path a vehicle would take to intercept or rendezvous with a target asteroid or comet, are described. Also, details are given of a tool that was created to model both the un-deflected inbound path of an NE0 as well as the modified, post-deflection, path. The number of possible options available for protection against the NE0 threat was too numerous for them to all be addressed within the study; instead, a representative selection were modeled and evaluated. The major output from this work was a novel process by which the relative effectiveness of different threat mitigation concepts can be evaluated during future, more detailed, studies. In addition, several new or modified mathematical models were developed to analyze various proposed protection systems. A summary of the major lessons learned during this study is presented, as are recommendations for future work. It is hoped that this study will serve to raise the level attention about this very real threat and also demonstrate that successful defense is both possible and practicable, provided appropriate steps are taken. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMNH23D1548D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMNH23D1548D">A Concept for Providing Warning of Chelyabinsk-like Meteors, including those approaching from the Sun</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Dunham, D. W.; Reitsema, H.; Lu, E.; Arentz, R.; Linfield, R.; Chapman, C. R.; Farquhar, R. W.; Furfaro, R.; Eismont, N. A.; Ledkov, A.; Chumachenko, E. 2013-12-01 The detonation of a 20m-asteroid above Chelyabinsk, Russia on 2013 February 15 shows that even small asteroids can cause extensive damage. Earth-based telescopes have found smaller harmless objects, such as 2008 TC3, discovered 20h before it exploded over northern Sudan . 2008 TC3 remains the only asteroid discovered before it hit Earth because it approached Earth from the night side, where it was observed by large telescopes searching for near-Earth objects. The larger object that exploded over Chelyabinsk approached Earth from the day side, from too close to the Sun to be detected from Earth. A sizeable telescope in an orbit about the Sun-Earth L1 (SE-L1) libration point 1.5 million km from Earth towards the Sun (about 4 times the distance to the Moon) could find objects like the 'Chelyabinsk' asteroid approaching approximately from the line of sight to the Sun about a day before Earth closest approach; this would find the approximately 35% of asteroids that approach Earth from a direction too close to the Sun to be observed, or likely to be missed, from the ground. Our concept would give at least several hours, and often a day or more, to take protective measures, rather than the approximately two-minute interval between the flash and shock wave arrival that occurred in Chelyabinsk. An important reason for providing warning of these events, even smaller harmless ones that explode high in the atmosphere with the force of an atomic bomb, is to prevent mistaking such an event for a nuclear attack that could trigger a devastating nuclear war. This concept could also discover many small asteroids that would not impact Earth; some of them would likely be suitable for retrieval to move to a lunar orbit for study by astronauts in the next decade. A concept using a space telescope similar to that needed by our concept is already conceived by the B612 Foundation, whose planned Sentinel Space Telescope could find nearly all 140m and larger near-Earth objects (NEO's), including those in orbits mostly inside the Earth's orbit that are hard to find with Earth-based telescopes, from a Venus-like orbit. Few modifications would be needed to the 50cm aperture passively-cooled infrared-observing Sentinel Space Telescope to operate in a SE-L1 orbit, 0.01 AU from Earth towards the Sun, to find most asteroids larger than about 5 meters that approach the Earth from the solar direction. Many objects in the 25-50m range will not be found by current NEO surveys, while they would nearly always be seen by this possible mission. A dense metallic NEO as small as 5m across can rain destruction over an area of 1 or 2 square kilometers, as the Sikhote-Alin meteor showed in 1947 Other concepts are either ineffective at providing warning of asteroids approaching from the Sun, or are more expensive, involving three or more spacecraft. We should give better warning for future 'Bolts out of the blue'. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050186569','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050186569">Near-Earth Object (NEO) Hazard Background</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Mazanek, Daniel D. 2005-01-01 The fundamental problem regarding NEO hazards is that the Earth and other planets, as well as their moons, share the solar system with a vast number of small planetary bodies and orbiting debris. Objects of substantial size are typically classified as either comets or asteroids. Although the solar system is quite expansive, the planets and moons (as well as the Sun) are occasionally impacted by these objects. We live in a cosmic shooting gallery where collisions with Earth occur on a regular basis. Because the number of smaller comets and asteroids is believed to be much greater than larger objects, the frequency of impacts is significantly higher. Fortunately, the smaller objects, which are much more numerous, are usually neutralized by the Earth's protective atmosphere. It is estimated that between 1000 and 10,000 tons of debris fall to Earth each year, most of it in the form of dust particles and extremely small meteorites. With no atmosphere, the Moon's surface is continuously impacted with dust and small debris. On November 17 and 18, 1999, during the annual Leonid meteor shower, several lunar surface impacts were observed by amateur astronomers in North America. The Leonids result from the Earth's passage each year through the debris ejected from Comet Tempel-Tuttle. These annual showers provide a periodic reminder of the possibility of a much more consequential cosmic collision, and the heavily cratered lunar surface acts a constant testimony to the impact threat. The impact problem and those planetary bodies that are a threat have been discussed in great depth in a wide range of publications and books, such as The Spaceguard Survey , Hazards Due to Comets and Asteroids, and Cosmic Catastrophes. This paper gives a brief overview on the background of this problem and address some limitations of ground-based surveys for detection of small and/or faint near-Earth objects. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E2199M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E2199M">A NEO population generation and observation simulation software tool</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Müller, Sven; Gelhaus, Johannes; Hahn, Gerhard; Franco, Raffaella One of the main targets of ESA's Space Situational Awareness (SSA) program is to build a wide knowledge base about objects that can potentially harm Earth (Near-Earth Objects, NEOs). An important part of this effort is to create the Small Bodies Data Centre (SBDC) which is going to aggregate measurement data from a fully-integrated NEO observation sensor network. Until this network is developed, artificial NEO measurement data is needed in order to validate SBDC algorithms. Moreover, to establish a functioning NEO observation sensor network, it has to be determined where to place sensors, what technical requirements have to be met in order to be able to detect NEOs and which observation strategies work the best. Because of this, a sensor simulation software was needed. This paper presents a software tool which allows users to create and analyse NEO populations and to simulate and analyse population observations. It is a console program written in Fortran and comes with a Graphical User Interface (GUI) written in Java and C. The tool can be distinguished into the components ``Population Generator'' and ``Observation Simulator''. The Population Generator component is responsible for generating and analysing a NEO population. Users can choose between creating fictitious (random) and synthetic populations. The latter are based on one of two models describing the orbital and size distribution of observed NEOs: The existing socalled ``Bottke Model'' (Bottke et al. 2000, 2002) and the new ``Granvik Model'' (Granvik et al. 2014, in preparation) which has been developed in parallel to the tool. Generated populations can be analysed by defining 2D, 3D and scatter plots using various NEO attributes. As a result, the tool creates the appropiate files for the plotting tool ``gnuplot''. The tool's Observation Simulator component yields the Observation Simulation and Observation Analysis functions. Users can define sensor systems using ground- or space-based locations as well as optical or radar sensors and simulate observation campaigns. The tool outputs field-of-view crossings and actual detections of the selected NEO population objects. Using the Observation Analysis users are able to process and plot the results of the Observation Simulation. In order to enable end-users to handle the tool in a user-intuitive and comfortable way, a GUI has been created based on the modular Eclipse Rich Client Platform (RCP) technology. Through the GUI users can easily enter input data for the tool, execute it and view its output data in a clear way. Additionally, the GUI runs gnuplot to create plot pictures and presents them to the user. Furthermore, users can create projects to organise executions of the tool. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018Icar..304....4M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018Icar..304....4M">The observing campaign on the deep-space debris WT1190F as a test case for short-warning NEO impacts</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Micheli, Marco; Buzzoni, Alberto; Koschny, Detlef; Drolshagen, Gerhard; Perozzi, Ettore; Hainaut, Olivier; Lemmens, Stijn; Altavilla, Giuseppe; Foppiani, Italo; Nomen, Jaime; Sánchez-Ortiz, Noelia; Marinello, Wladimiro; Pizzetti, Gianpaolo; Soffiantini, Andrea; Fan, Siwei; Frueh, Carolin 2018-04-01 On 2015 November 13, the small artificial object designated WT1190F entered the Earth atmosphere above the Indian Ocean offshore Sri Lanka after being discovered as a possible new asteroid only a few weeks earlier. At ESA's SSA-NEO Coordination Centre we took advantage of this opportunity to organize a ground-based observational campaign, using WT1190F as a test case for a possible similar future event involving a natural asteroidal body. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MsT..........1F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MsT..........1F">Automatic detection of asteroids by 16" and 41" telescopes at the SFA Observatory</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Fuls, David Carson 2015-05-01 Major upgrades were carried out to the hardware and software of the 16-inch and 41-inch telescopes at the Stephen F. Austin State University Observatory. These upgrades allow remote operation of both telescopes and are specifically designed to enhance the amount of time the telescopes are looking for Near Earth Objects (NEO's). This ability was tested by obtaining images and astrometry data remotely from both telescopes of target NEO's which required follow-up observation. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170000010','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170000010">Phase-Angle Dependence of Determinations of Diameter, Albedo, and Taxonomy: A Case Study of NEO 3691 Bede</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Wooden, Diane H.; Lederer, Susan M.; Jehin, Emmanuel; Howell, Ellen S.; Fernandez, Yan; Harker, David E.; Ryan, Erin; Lovell, Amy; Woodward, Charles E.; Benner, Lance A. 2015-01-01 Parameters important for NEO risk assessment and mitigation include Near-Earth Object diameter and taxonomic classification, which translates to surface composition. Diameters of NEOs are derived from the thermal fluxes measured by WISE, NEOWISE, Spitzer Warm Mission and ground-based telescopes including the IRTF and UKIRT. Diameter and its coupled parameters Albedo and IR beaming parameter (a proxy for thermal inertia and/or surface roughness) are dependent upon the phase angle, which is the Sun-target-observer angle. Orbit geometries of NEOs, however, typically provide for observations at phase angles greater than 20 degrees. At higher phase angles, the observed thermal emission is sampling both the day and night sides of the NEO. We compare thermal models for NEOs that exclude (NEATM) and include (NESTM) night-side emission. We present a case study of NEO 3691 Bede, which is a higher albedo object, X (Ec) or Cgh taxonomy, to highlight the range of H magnitudes for this object (depending on the albedo and phase function slope parameter G), and to examine at different phase angles the taxonomy and thermal model fits for this NEO. Observations of 3691 Bede include our observations with IRTF+SpeX and with the 10 micrometer UKIRT+Michelle instrument, as well as WISE and Spitzer Warm mission data. By examining 3691 Bede as a case study, we highlight the interplay between the derivation of basic physical parameters and observing geometry, and we discuss the uncertainties in H magnitude, taxonomy assignment amongst the X-class (P, M, E), and diameter determinations. Systematic dependencies in the derivation of basic characterization parameters of H-magnitude, diameter, albedo and taxonomy with observing geometry are important to understand. These basic characterization parameters affect the statistical assessments of the NEO population, which in turn, affects the assignment of statistically-assessed basic parameters to discovered but yet-to-be-fully-characterized NEOs. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010mia..confE...5B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010mia..confE...5B">Near-Earth Asteroids Astrometry with Gaia and Beyond</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Bancelin, D.; Hestroffer, D.; Thuillot, W. 2010-05-01 Gaia is an astrometric mission from the European Space Agency (ESA) that will be launched in Spring 2012. The Gaia telescope and spectrometer will operate in the visible wavelength scanning the whole sky during 5 years (nominal mission duration). It will observe about one billion stars and QSOs but also a large number of solar system bodies, mainly asteroids, and a few comets and planetary satellites. The unprecedented accuracy of the measures both astrometric and photometric (note that the spectroscopic observations are of little scientific value for Solar System objects science) will enable to significantly improve the knowledge of the dynamics and physical properties for a large number of asteroids. With a relatively limiting magnitude somewhat reduced to V≤20 (compared to other future or ongoing surveys) Gaia will mainly oserve main-belt asteroids (MBAs), and very few TNOs or Centaurs. The Gaia telescope will also be able to observe several thousands of Near- Earth Objects (NEOs) down to low solar elongation (observation of solar system objects are performed with elongation 45° ≤ L ≤ 135°). Gaia will not be a ''big'' NEO discover, however it can possibly discover inner-Earth orbiting objects (IEOs) or sub-Atens, from atmosphereless low solar-elongation observations. In the case of discovering a new NEO target, ground-based observations in network could be needed to avoid confusion in identifying the object in the database, or loss of the target. We are aiming to generate VO-alert for such eventuality. Ground-based observations of NEOs would also more generally enter into the operational centre in construction at the IMCCE that will deal with data mining, astrometric reduction, orbit computation, alerts, etc. On the other hand, in the framework of ESA Space Situational Awareness (SSA), ground-based astrometry, possibly complemented by Gaia data, is needed to refine the orbits and collision assessment of PHAs. High accuracy astrometric and colour-photometry observations of NEOs will provide information on their taxonomy, spin state and shape, and detailed information of their orbits. Small effects acting on their dynamics can then be measured; these include link of reference frame (kinematically non rotating and dynamically non rotating one), local tests of the General Relativity and measure of the solar quadrupole J2 basically from the drift of the perihelion, test of the variation of the constant of gravity dG/dt, and detection of non gravitational effect such as the thermal Yarkovsky effect and cometary activity. Dedicated ground-based observations can be used on specific targets to complement the limited wavelength, time resolution and imaging capabilities of the Gaia telescope. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4832711A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4832711A">Flagstaff Robotic Survey Telescope (FRoST): Rapid Response for NEOs</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Avner, Louis Daniel; Trilling, David E.; Dunham, Edward W. 2016-10-01 The Flagstaff Robotic Survey Telescope (FRoST) is a robotic 0.6m Schmidt telescope that will be used for instant follow-up observations of newly discovered Near Earth Objects (NEOs). Here, we present the progress being made on FRoST as well as the remaining tasks until the telescope is fully operational. With more than one thousand NEOs being found yearly, more telescopes are needed to carry out follow-up observations. Most NEOs are found at their peak brightness, meaning that these observations need to happen quickly before they fade. By using the Catalina Sky Survey Queue Manager, FRoST will be able to accept interruptions during the night and prioritize observations automatically, allowing instant follow-up observations. FRoST will help refine the orbit of these newly discovered objects while providing optical colors. We will ingest information from the NEOCP and JPL's Scout program at five minute intervals and observe newly discovered targets robotically, process the data automatically, and autonomously generate astrometry and colors. We estimate that will we provide essentially 100% recovery of objects brighter than V~20. This work was supported by the NSF MRI program as well as by NAU and Lowell Observatory. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005DPS....37.1531H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005DPS....37.1531H">Exploration-driven NEO Detection Requirements</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Head, J. N.; Sykes, M. V. 2005-12-01 The Vision for Space Exploration calls for use of in situ resources to support human solar system exploration goals. Focus has been on potential lunar polar ice, Martian subsurface water and resource extraction from Phobos. Near-earth objects (NEOs) offer easily accessible targets that may represent a critical component to achieving sustainable human operations, in particular small, newly discovered asteroids within a specified dynamical range having requisite composition and frequency. A minimum size requirement is estimated assuming CONOPs has an NEO harvester on station at L1. When the NEO launch window opens, the vehicle departs, rendezvousing within 30 days. Mining and processing operations ( 60 days) produces dirty water for the return trip ( 30 days) to L1 for final refinement into propellants. A market for propellant at L1 is estimated to be 700 mT /year: 250 mT for Mars missions, 100 mT for GTO services (Blair et al. 2002), 50 mT for L1 to lunar surface services, and 300 mT for bringing NEO-derived propellants to L1. Assuming an appropriate NEO has 5% recoverable water, exploited with 50% efficiency, 23000 mT/year must be processed. At 1500 kg/m3, this corresponds to one object per year with a radius of 15 meters, or two 5 m radius objects per month, of which it is estimated there are 10000 having delta-v < 4.2 km/s and 200/year of these available for short roundtrip missions to meet resource requirements (Jones et al. 2002). The importance of these potential resource objects should drive a requirement that next generation NEO detection systems (e.g., Pan-STARRS/LSST) be capable by 2010 of detecting dark NEOs fainter than V=24, allowing for identification 3 months before closest approach. Blair et al. 2002. Final Report to NASA Exploration Team, December 20, 2002. Jones et al. 2002. ASP Conf. Series Vol. 202 (M. Sykes, Ed.), pp. 141-154. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920073049&hterms=protect&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dprotect','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920073049&hterms=protect&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dprotect">An international program to protect the earth from impact catastrophe - Initial steps</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Morrison, David 1992-01-01 Risks posed by impacting objects of various sizes are analyzed using the Spaceguard Survey, the 1992 NASA report of International Near-Earth-Object (NEO) Detection workshop. The state-of-the-art technology makes it possible to discover and track nearly all earth-crossing asteroids and short-period comets large enough to threaten global catastrophe. To deal with this hazard a long-term telescopic search is required that reaches stellar magnitude 22 in order to achieve a nearly complete census of objects 1 km or larger. A program can be performed on the basis of an international network of six telescopes of 2-3 m aperture equipped with modern CCD detectors and automatic signal processing capability. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active">8</li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active">9</li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/22047881-production-near-earth-asteroids-retrograde-orbits','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22047881-production-near-earth-asteroids-retrograde-orbits"></a> <a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Greenstreet, S.; Gladman, B.; Ngo, H. While computing an improved near-Earth object (NEO) steady-state orbital distribution model, we discovered in the numerical integrations the unexpected production of retrograde orbits for asteroids that had originally exited from the accepted main-belt source regions. Our model indicates that {approx}0.1% (a factor of two uncertainty) of the steady-state NEO population (perihelion q < 1.3 AU) is on retrograde orbits. These rare outcomes typically happen when asteroid orbits flip to a retrograde configuration while in the 3:1 mean-motion resonance with Jupiter and then live for {approx}0.001 to 100 Myr. The model predicts, given the estimated near-Earth asteroid (NEA) population, that amore » few retrograde 0.1-1 km NEAs should exist. Currently, there are two known MPC NEOs with asteroidal designations on retrograde orbits which we therefore claim could be escaped asteroids instead of devolatilized comets. This retrograde NEA population may also answer a long-standing question in the meteoritical literature regarding the origin of high-strength, high-velocity meteoroids on retrograde orbits.« less </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150022454','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150022454">An Optimal Mitigation Strategy Against the Asteroid Impact Threat with Short Warning Time</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Wie, Bong; Barbee, Brent W. 2015-01-01 This paper presents the results of a NASA Innovative Advanced Concept (NIAC) Phase 2 study entitled "An Innovative Solution to NASA's Near-Earth Object (NEO) Impact Threat Mitigation Grand Challenge and Flight Validation Mission Architecture Development." This NIAC Phase 2 study was conducted at the Asteroid Deflection Research Center (ADRC) of Iowa State University in 2012-2014. The study objective was to develop an innovative yet practically implementable mitigation strategy for the most probable impact threat of an asteroid or comet with short warning time (less than 5 years). The mitigation strategy described in this paper is intended to optimally reduce the severity and catastrophic damage of the NEO impact event, especially when we don't have sufficient warning times for non-disruptive deflection of a hazardous NEO. This paper provides an executive summary of the NIAC Phase 2 study results. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PASP..128d5004M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PASP..128d5004M">Comparing NEO Search Telescopes</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Myhrvold, Nathan 2016-04-01 Multiple terrestrial and space-based telescopes have been proposed for detecting and tracking near-Earth objects (NEOs). Detailed simulations of the search performance of these systems have used complex computer codes that are not widely available, which hinders accurate cross-comparison of the proposals and obscures whether they have consistent assumptions. Moreover, some proposed instruments would survey infrared (IR) bands, whereas others would operate in the visible band, and differences among asteroid thermal and visible-light models used in the simulations further complicate like-to-like comparisons. I use simple physical principles to estimate basic performance metrics for the ground-based Large Synoptic Survey Telescope and three space-based instruments—Sentinel, NEOCam, and a Cubesat constellation. The performance is measured against two different NEO distributions, the Bottke et al. distribution of general NEOs, and the Veres et al. distribution of Earth-impacting NEO. The results of the comparison show simplified relative performance metrics, including the expected number of NEOs visible in the search volumes and the initial detection rates expected for each system. Although these simplified comparisons do not capture all of the details, they give considerable insight into the physical factors limiting performance. Multiple asteroid thermal models are considered, including FRM, NEATM, and a new generalized form of FRM. I describe issues with how IR albedo and emissivity have been estimated in previous studies, which may render them inaccurate. A thermal model for tumbling asteroids is also developed and suggests that tumbling asteroids may be surprisingly difficult for IR telescopes to observe. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IAUGA..2249572M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IAUGA..2249572M">The ESA SSA NEO Coordination Centre contribution to NEO hazard monitoring and observational campaigns</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Micheli, Marco; Borgia, Barbara; Drolshagen, Gerhard; Koschny, Detlef; Perozzi, Ettore 2015-08-01 The NEO Coordination Centre (NEOCC) has recently been established in Frascati, near Rome, within the framework of the ESA Space Situational Awareness (SSA) Programme. Among its tasks is the coordination of observational activities related to the NEO hazard, and the distribution of relevant and up-to-date information on NEOs to both the scientific community and general users through its web portal (http://neo.ssa.esa.int).On the observational side, the NEOCC is linked to an increasingly large worldwide network of collaborating observatories, ranging from amateurs observers to large professional telescopes. The Centre organizes observation campaigns, alerting the network to suggest urgent or high-priority observations, and providing them with observational support.The NEOCC is also directly obtaining astrometric observations of high-priority targets, especially Virtual Impactors (VIs), on challenging objects as faint as magnitude 26.5, thanks to successful collaborations with ESO VLT in Chile and the INAF-sponsored LBT in Arizona. In addition, the Centre carries out regular monthly runs dedicated to NEO follow-up, recovery and survey activities with the 1-meter ESA OGS telescope in Tenerife.From a service perspective, the NEO System hosted at the NEOCC collects data and information on NEOs produced by various European services (e.g. NEODyS, EARN) and makes them available to a variety of users, with a particular focus on objects with possible collision solutions with the Earth. Among the tools provided through the web portal are the Risk List (a table of all known NEOs with impact solutions), a table of recent and upcoming close approaches, a database of physical properties of NEOs and the so-called Priority List, which allows observers to identify NEOs in most urgent need of observations, and prioritise their observational activities accordingly.The results of our recent observation campaigns and some major recent improvements to the NEO System will presented and discussed in detail. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110000788','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110000788">Initial Considerations for Navigation and Flight Dynamics of a Crewed Near-Earth Object Mission</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Holt, Greg N.; Getchius, Joel; Tracy, William H. 2011-01-01 A crewed mission to a Near-Earth Object (NEO) was recently identified as a NASA Space Policy goal and priority. In support of this goal, a study was conducted to identify the initial considerations for performing the navigation and flight dynamics tasks of this mission class. Although missions to a NEO are not new, the unique factors involved in human spaceflight present challenges that warrant special examination. During the cruise phase of the mission, one of the most challenging factors is the noisy acceleration environment associated with a crewed vehicle. Additionally, the presence of a human crew necessitates a timely return trip, which may need to be expedited in an emergency situation where the mission is aborted. Tracking, navigation, and targeting results are shown for sample human-class trajectories to NEOs. Additionally, the benefit of in-situ navigation beacons on robotic precursor missions is presented. This mission class will require a longer duration flight than Apollo and, unlike previous human missions, there will likely be limited communication and tracking availability. This will necessitate the use of more onboard navigation and targeting capabilities. Finally, the rendezvous and proximity operations near an asteroid will be unlike anything previously attempted in a crewed spaceflight. The unknown gravitational environment and physical surface properties of the NEO may cause the rendezvous to behave differently than expected. Symbiosis of the human pilot and onboard navigation/targeting are presented which give additional robustness to unforeseen perturbations. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170002066','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170002066">Optimal Fragmentation and Dispersion of Hazardous Near-Earth Objects</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Wie, Bong 2012-01-01 The complex problem of protecting the Earth from the possibility of a catastrophic impact by a hazardous near-Earth object (NEO) has been recently reassessed in [1]. In a letter on NEOs from the White House Office of Science and Technology Policy (OSTP) to the U.S. Senate and Congress in 2010, the White House OSTP strongly recommended that NASA take the lead in conducting research activities for NEO detection, characterization, and deflection technologies. Furthermore, President Obama's new National Space Policy specifically directs NASA to "pursue capabilities, in cooperation with other departments, agencies, and commercial partners, to detect, track, catalog, and characterize NEOs to reduce the risk of harm to humans from an unexpected impact on our planet." The Planetary Defense Task Force of the NASA Advisory Council also recommended that the NASA Office of the Chief Technologist (OCT) begin efforts to investigate asteroid deflection techniques. With national interest growing in the United States, the NEO threat detection and mitigation problem was recently identified as one of NASA's Space Technology Grand Challenges. An innovative solution to NASA's NEO Impact Threat Mitigation Grand Challenge problem was developed through a NIAC Phase I study (9/16/11 - 9/15/12), and it will be further investigated for a NIAC Phase II study (9/10/12 - 9/9/14). Various NEO deflection technologies, including nuclear explosions, kinetic impactors, and slow-pull gravity tractors, have been proposed and examined during the past two decades. Still, there is no consensus on how to reliably deflect or disrupt hazardous NEOs in a timely manner. It is expected that the most probable mission scenarios will have a mission lead time much shorter than 10 years, so the use of nuclear explosives becomes the most feasible method for planetary defense. Direct intercept missions with a short warning time will result in arrival closing velocities of 10-30 kilometers per second with respect to the target asteroid. Given such a large arrival delta V requirement, a rendezvous mission to the target asteroid is infeasible with existing launch vehicles. Furthermore, state-of-the-art penetrating subsurface nuclear explosion technology limits the penetrator's impact velocity to less than approximately 300 meters per second because higher impact velocities prematurely destroy the nuclear fuzing mechanisms. Therefore, significant advances in hypervelocity nuclear interceptor/ penetrator technology must be achieved to enable a last-minute nuclear disruption mission with intercept velocities as high as 30 kilometers per second. Consequently, a HAIV (Hypervelocity Asteroid Intercept Vehicle) mission architecture (Figure 1.1), which blends a hypervelocity kinetic impactor with a subsurface nuclear explosion for optimal fragmentation and dispersion of hazardous NEOs, has been developed through a Phase I study, and it will be further developed and validated through a Phase II study. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20150006904&hterms=Layout+Design&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DLayout%2BDesign','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20150006904&hterms=Layout+Design&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DLayout%2BDesign">Power and Propulsion System Design for Near-Earth Object Robotic Exploration</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Snyder, John Steven; Randolph, Thomas M.; Landau, Damon F.; Bury, Kristen M.; Malone, Shane P.; Hickman, Tyler A. 2011-01-01 Near-Earth Objects (NEOs) are exciting targets for exploration; they are relatively easy to reach but relatively little is known about them. With solar electric propulsion, a vast number of interesting NEOs can be reached within a few years and with extensive flexibility in launch date. An additional advantage of electric propulsion for these missions is that a spacecraft can be small, enabling a fleet of explorers launched on a single vehicle or as secondary payloads. Commercial, flight-proven Hall thruster systems have great appeal based on their performance and low cost risk, but one issue with these systems is that the power processing units (PPUs) are designed for regulated spacecraft power architectures which are not attractive for small NEO missions. In this study we consider the integrated design of power and propulsion systems that utilize the capabilities of existing PPUs in an unregulated power architecture. Models for solar array and engine performance are combined with low-thrust trajectory analyses to bound spacecraft design parameters for a large class of NEO missions, then detailed array performance models are used to examine the array output voltage and current over a bounded mission set. Operational relationships between the power and electric propulsion systems are discussed, and it is shown that both the SPT-100 and BPT-4000 PPUs can perform missions over a solar range of 0.7 AU to 1.5 AU - encompassing NEOs, Venus, and Mars - within their operable input voltage ranges. A number of design trades to control the array voltage are available, including cell string layout, array offpointing during mission operations, and power draw by the Hall thruster system. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AcAau.111..198B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AcAau.111..198B">Target selection and mass estimation for manned NEO exploration using a baseline mission design</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Boden, Ralf C.; Hein, Andreas M.; Kawaguchi, Junichiro 2015-06-01 In recent years Near-Earth Objects (NEOs) have received an increased amount of interest as a target for human exploration. NEOs offer scientifically interesting targets, and at the same time function as a stepping stone for achieving future Mars missions. The aim of this research is to identify promising targets from the large number of known NEOs that qualify for a manned sample-return mission with a maximum duration of one year. By developing a baseline mission design and a mass estimation model, mission opportunities are evaluated based on on-orbit mass requirements, safety considerations, and the properties of the potential targets. A selection of promising NEOs is presented and the effects of mission requirements and restrictions are discussed. Regarding safety aspects, the use of free-return trajectories provides the lowest on-orbit mass, when compared to an alternative design that uses system redundancies to ensure return of the spacecraft to Earth. It is discovered that, although a number of targets are accessible within the analysed time frame, no NEO offers both easy access and high incentive for its exploration. Under the discussed aspects a first human exploration mission going beyond the vicinity of Earth will require a trade off between targets that provide easy access and those that are of scientific interest. This lack of optimal mission opportunities can be seen in the small number of only 4 NEOs that meet all requirements for a sample-return mission and remain below an on-orbit mass of 500 metric Tons (mT). All of them require a mass between 315 and 492 mT. Even less ideal, smaller asteroids that are better accessible require an on-orbit mass that exceeds the launch capability of future heavy lift vehicles (HLV) such as SLS by at least 30 mT. These mass requirements show that additional efforts are necessary to increase the number of available targets and reduce on-orbit mass requirements through advanced mission architectures. The need for on-orbit assembly also becomes apparent, as availability of a HLV alone does not provide sufficient payload capabilities for any manned mission targeting NEOs. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001DPS....33.4109B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001DPS....33.4109B">Catalog based two-color, relative photometry of NEOs at McDonald Observatory</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Barker, E. S.; Györgyey Ries, J.; Shelus, P. J.; Ricklefs, R. L. 2001-11-01 The McDonald Observatory astrometry group has been involved in Solar System positional observations since the early 1970's. Since 1995, it has evolved to a CCD-based, almost totally automated, astrometry package. We are focusing our observational program on Near Earth Objects (NEOs) as part of NASA's mission to discover and catalogue 90 percent of NEOs with diameters larger than 1 km by 2008. We carry out confirmation observations of newly discovered objects and contribute to orbit improvements of under-observed objects. Understanding the overall hazard that these objects pose to Earth requires their dynamical and physical characterization. We recently adopted the USNO-A2.0 catalogue to improve our astrometric results. The catalog, however, also provides stellar magnitudes in the standard Johnson R and B photometric bands. After completing the night’s observing program, we now regularly provide the IAU with R magnitudes in addition to astrometric positions. Our limiting magnitude in R is near 22 in a 15 minute exposure over a 46 arcmin field on the 0.8m prime focus camera. Typically, we are scheduled for 4 nights each lunation, but our semi-automated, IRAF/ICE based program can be used by other 0.8m users. We are testing procedures that will include B and V exposures as part of our standard confirmation triplet. We have confirmed that switching filters between exposures on standard fields does not compromise the astrometric accurary. Thus, we should be able to provide two color, sequential, relative photometry of any newly discovered asteroid, as part of the confirmation process. The time interval between exposures is less than 20 minutes, short compared to most asteroid rotation times. Consequently, a meaningful color index can be obtained in parallel with the astrometric positions. Although B-R is not the usual color index used in asteroid classification studies, we are testing whether we can use it as a quick diagnostic tool to roughly classify newly discovered NEOs as by product of our astrometric observing sequence. Preliminary results will be presented at the meeting. This research is funded by NASA's NEO Observation Program grants NAG5-6863 and NAG5-10183. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMIN11D..03W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMIN11D..03W">NASA Earth Observations (NEO): Data Imagery for Education and Visualization</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Ward, K. 2008-12-01 NASA Earth Observations (NEO) has dramatically simplified public access to georeferenced imagery of NASA remote sensing data. NEO targets the non-traditional data users who are currently underserved by functionality and formats available from the existing data ordering systems. These users include formal and informal educators, museum and science center personnel, professional communicators, and citizen scientists. NEO currently serves imagery from 45 different datasets with daily, weekly, and/or monthly temporal resolutions, with more datasets currently under development. The imagery from these datasets is produced in coordination with several data partners who are affiliated either with the instrument science teams or with the respective data processing center. NEO is a system of three components -- website, WMS (Web Mapping Service), and ftp archive -- which together are able to meet the wide-ranging needs of our users. Some of these needs include the ability to: view and manipulate imagery using the NEO website -- e.g., applying color palettes, resizing, exporting to a variety of formats including PNG, JPEG, KMZ (Google Earth), GeoTIFF; access the NEO collection via a standards-based API (WMS); and create customized exports for select users (ftp archive) such as Science on a Sphere, NASA's Earth Observatory, and others. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002EGSGA..27.4845S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002EGSGA..27.4845S">Relative 2-color Photometry Of Neo's</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Shelus, P.; Gyorgyey-Ries, J.; Ricklefs, R.; Barker, E. We have been making Solar System small body positional observations at McDon- ald Observatory since the early 1970's. In 1994 we moved to a CCD-based, almost totally automated, astrometry system (Whipple et al, 1996, Astron. J., Vol. 112, p. 316). Our present observational effort is focussed upon Near Earth Objects (NEOs) as part of NASA's mission to discover and catalogue 90 percent of NEOs with diameters larger than 1 km by 2008. Observing 4 nights per lunation, we conduct observations to confirm newly discovered NEOs, filling in the night on a target-of-opportunnity basis, with observations of under-observed NEOs. Our major intent is to understand the overall hazard that these objects pose to Earth and their dynamical and physical characterization. We recently adopted the USNO-A2.0 catalogue to improve astromet- ric results and a number of up-grades to the end-to-end system have been developed (Barker et al, 2001, Bull. AAS, Vol. 33, p. 1116). The USNO catalog also provides stellar magnitudes in the standard Johnson R and B photometric bands. We have thus taken the opportunity to expand our observational efforts to regularly provide R mag- nitudes, in addition to astrometric positions. Our limiting magnitude in R is near 22. We are now furthering our photometric efforts by including B exposures as part of our standard observation triplet. We have already confirmed that switching filters between exposures on standard fields does not compromise the astrometric accurary. Thus, we plan to provide two color, sequential, relative photometry, (B-R), of newly discov- ered or under observed asteroids, as part of our routine observation process. The time interval between exposures is always less than 20 minutes, short compared to most asteroid rotation times. Consequently, a meaningful color index can be obtained in parallel with the astrometric positions. Although (B-R) is not the usual color index used in asteroid classification studies, we are testing whether we can use it as a quick diagnostic tool to roughly classify newly discovered NEOs. The results so far obtained are presented here. This research is funded by NASA's NEO Observation Program grants NAG5-6863 and NAG5-10183. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DPS....4721314H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DPS....4721314H">Visible Wavelength Reflectance Spectra and Taxonomies of Near-Earth Objects from Apache Point Observatory</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Hammergren, Mark; Brucker, Melissa J.; Nault, Kristie A.; Gyuk, Geza; Solontoi, Michael R. 2015-11-01 Near-Earth Objects (NEOs) are interesting to scientists and the general public for diverse reasons: their impacts pose a threat to life and property; they present important albeit biased records of the formation and evolution of the Solar System; and their materials may provide in situ resources for future space exploration and habitation.In January 2015 we began a program of NEO astrometric follow-up and physical characterization using a 17% share of time on the Astrophysical Research Consortium (ARC) 3.5-meter telescope at Apache Point Observatory (APO). Our 500 hours of annual observing time are split into frequent, short astrometric runs (see poster by K. A. Nault et. al), and half-night runs devoted to physical characterization (see poster by M. J. Brucker et. al for preliminary rotational lightcurve results). NEO surface compositions are investigated with 0.36-1.0 μm reflectance spectroscopy using the Dual Imaging Spectrograph (DIS) instrument. As of August 25, 2015, including testing runs during fourth quarter 2014, we have obtained reflectance spectra of 68 unique NEOs, ranging in diameter from approximately 5m to 8km.In addition to investigating the compositions of individual NEOs to inform impact hazard and space resource evaluations, we may examine the distribution of taxonomic types and potential trends with other physical and orbital properties. For example, the Yarkovsky effect, which is dependent on asteroid shape, mass, rotation, and thermal characteristics, is believed to dominate other dynamical effects in driving the delivery of small NEOs from the main asteroid belt. Studies of the taxonomic distribution of a large sample of NEOs of a wide range of sizes will test this hypothesis.We present a preliminary analysis of the reflectance spectra obtained in our survey to date, including taxonomic classifications and potential trends with size.Acknowledgements: Based on observations obtained with the Apache Point Observatory 3.5-meter telescope, which is owned and operated by the Astrophysical Research Consortium. We gratefully acknowledge support from NASA NEOO award NNX14AL17G, and thank the University of Chicago Department of Astronomy and Astrophysics for observing time in 2014. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120003744','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120003744">Feasibility of Large High-Powered Solar Electric Propulsion Vehicles: Issues and Solutions</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Capadona, Lynn A.; Woytach, Jeffrey M.; Kerslake, Thomas W.; Manzella, David H.; Christie, Robert J.; Hickman, Tyler A.; Schneidegger, Robert J.; Hoffman, David J.; Klem, Mark D. 2012-01-01 Human exploration beyond low Earth orbit will require the use of enabling technologies that are efficient, affordable, and reliable. Solar electric propulsion (SEP) has been proposed by NASA s Human Exploration Framework Team as an option to achieve human exploration missions to near Earth objects (NEOs) because of its favorable mass efficiency as compared to traditional chemical systems. This paper describes the unique challenges and technology hurdles associated with developing a large high-power SEP vehicle. A subsystem level breakdown of factors contributing to the feasibility of SEP as a platform for future exploration missions to NEOs is presented including overall mission feasibility, trip time variables, propellant management issues, solar array power generation, array structure issues, and other areas that warrant investment in additional technology or engineering development. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014acm..conf..482S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014acm..conf..482S">Analysis of ejecta fate from proposed man-made impactors into near-Earth objects --- a NEOShield study</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Schwartz, S.; Michel, P.; Jutzi, M. 2014-07-01 Asteroids measuring 100 meters across tend to impact the Earth once every 5,000 years on average [1]. Smaller bodies enter into the Earth's atmosphere more frequently, but may detonate before reaching the surface. Conversely, impacts from larger bodies are more rare [2], but can come with devastating global consequences to living species. In 2005, a United States Congressional mandate called for NASA to detect, by 2020, 90 percent of near-Earth objects (NEOs) having diameters of 140 meters or greater [3]. One year prior, ESA's Near-Earth Object Mission Advisory Panel (NEOMAP) recommended the study of a kinetic impactor mission as a priority in the framework of NEO risk assessment [4]. A ''Phase-A'' study of such a mission, Don Quixote, took place at ESA until 2007. In accordance with NEOMAP and with the Target NEO Global Community's recommendations in 2011 [5], the NEOShield Project is being funded for 3.5 years by the European Commission in its FP7 program. NEOShield began in 2012 and is primarily, but not exclusively, a European consortium of research institutions and engineering industries that aims to analyze promising mitigation options and provide solutions to the critical scientific and technical obstacles involved in confronting threats posed by the small bodies in the neighborhood of the Earth's orbit [6]. To further explore the NEO threat mitigation via the strategy of kinetic impact, building upon the Don Quixote study, the idea is to target a specific NEO for impact and attempt to quantify the response. How long do ejecta remain aloft and where do they end up? Fragments that are ejected at high speeds escape, but what about material moving at or near the escape speed of the NEO or that suffer energy-dissipating collisions after being ejected? Where would be a ''safe'' location for an observing spacecraft during and subsequent to the impact? Here, we outline the early phases of an ongoing numerical investigation of the fate of the material ejected from a targeted spacecraft impact, part of a specific work package of NEOShield. To compute the initial, hypervelocity, phase of the impact (0.3 s), we use a Smoothed Particle Hydrodynamics (SPH) impact code, specially written to model geologic materials [7], using the Tillotson equation of state, a standard Drucker-Prager yield criterion for rocky materials, and a modified Grady-Kip tensile fracture model relying on a Weibull distribution of incipient flaws [8]. To determine the fate of the ejecta, the output is then ported into the N-Body code, PKDGRAV, originally developed for cosmological modeling of large-scale structure at the University of Washington [9]; the code was then outfitted to handle collisions and adapted for planetary-science applications [10]. We take advantage of PKDGRAV's sophisticated neighbor-finding tree to run its gravity solver and search for contacts as part of a soft-sphere collisional routine [11]. Simulating the evolution of the ejecta cloud is complex, involving a lot of material moving at a wide range of speeds. The fastest-moving ejecta easily escape the weak pull of the asteroid's gravity, but the trajectories of material sent aloft at or near escape speed must be followed for weeks in order to determine their fate. Slow-moving material lingers in the weak gravitational field, potentially posing a risk to nearby spacecraft (e.g., the ''orbiter'' in the Don Quixote study), and obscuring data collection, by ground- and/or space-based detectors, in the aftermath of the impact. Results of the study will be furnished. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016IAUS..318..319T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016IAUS..318..319T">Klenot Project - Near Earth Objects Follow-Up Program</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Tichý, Miloš; Tichá, Jana; Kočer, Michal 2016-01-01 NEO research is a great challenge just now - for science, for exploration and for planetary defence. Therefore NEO discoveries, astrometric follow-up, orbit computations as well as physical studies are of high interest both to science community and humankind. The KLENOT Project of the Klet Observatory, South Bohemia, Czech Republic pursued the confirmation, early follow-up, long-arc follow-up and recovery of Near Earth Objects since 2002. Tens of thousands astrometric measurements helped to make inventory of NEOs as well as to understand the NEO population. It ranked among the world most prolific professional NEO follow-up programmes during its first phase from 2002 to 2008. The fundamental improvement of the 1.06-m KLENOT Telescope was started in autumn 2008. The new computer controlled paralactic mount was built to substantially increase telescope-time efficiency, the number of observations, their accuracy and limiting magnitude. The testing observations of the KLENOT Telescope Next Generation (NG) were started in October 2011. The new more efficient CCD camera FLI ProLine 230 was installed in summer 2013. The original Klet Software Package has been continually upgraded over the past two decades of operation. Along with huge hardware changes we have decided for essential changes in software and the whole KLENOT work-flow. Using the current higher computing power available, enhancing and updating our databases and astrometry program, the core of our software package, will prove highly beneficial. Moreover, the UCAC4 as the more precise astrometric star catalog was implemented. The modernized KLENOT System was put into full operation in September 2013. This step opens new possibilities for the KLENOT Project, the long-term European Contribution to Monitoring and Cataloging Near Earth Objects. KLENOT Project Goals are confirmatory observations of newly discovered fainter NEO candidates, early follow-up of newly discovered NEOs, long-arc follow-up astrometry of NEOs in need of further data. The higher priority is given to Potentially Hazardous Asteroids (PHAs) and Virtual Impactors (VIs), recoveries of NEOs in the second opposition and also follow-up astrometry of radar or mission targets, special follow-up requests and follow-up astrometry of other unusual objects (comets, bright TNOs) including analysis of cometary features of suspected bodies, and also search for new asteroids, especially NEOs as well as other objects showing unusual motion. The KLENOT Telescope is located at the Klet Observatory, South Bohemia, Czech Republic (Central Europe), at geographical position: latitude 14° 17' 17'' E, longitude 48° 51' 48''N, elevation 1068 meters above sea level, in a rather dark site in the middle of the Protected Landscape Area Blanský les. Average number of clear nights per year about 120. Our IAU/MPC code is 246 KLENOT Project Advantages: • full observing time is dedicated to the KLENOT team • quick changes in an observing plan possible, even during an observing night • long-term NEO activities at Klet (since 1992) • experienced observers/measurers visually validate each moving object candidate • real-time processing of targeted objects KLENOT Next Generation Telescope technical data (since 2013): • new computer controlled paralactic mount • 1.06-m f/3 main mirror (Zeiss) • four lenses primary focus corrector • 1.06-m f/2.7 optical system • CCD camera FLI ProLine PL230 • chip e2v 2048 × 2048 pixels, pixel size 15 microns, Peltier cooling • FOV 37 × 37 arcminutes, image scale 1.1 arcseconds per pixel • limiting magnitude m V=21.5 mag. for 120-sec exposure time KLENOT Project First Phase Results(2002-2008) total of 52,658 astrometric measurements of 5,867 bodies, it contains: • 13,342 astrometric measurements of 1,369 NEAs (MPC,NEODys) • confirmation and astrometry of 623 NEAs from NEOCP (MPECs) • recoveries of 4 comets and 16 NEAs (including 196P/Tichý) • astrometry of 157 Virtual Impactors (CLOMON, SENTRY) • detection of cometary features of 34 bodies (IAUCs) • discovery of splitting of comet C/2004 S1 (Van Ness) • independent discovery of 4 fragments of comet 73P/S-W 3 • asteroid discoveries - 750 bodies • 3 NEOs - Apollo 2002 LK, Aten 2003 UT55, Apollo 2006 XR4, 1 JFA 2004 RT109 The first KLENOT Project Next Generation Results (since 2011) total of 10,054 astrometric measurements of 1,298 bodies, it contains: • 2,211 astrometric measurements of 263 NEAs(MPC,NEODys) • confirmation and astrometry of 143 NEAs from NEOCP (MPECs) • astrometry of 18 Virtual Impactors (CLOMON, SENTRY) • detection of cometary features of 5 bodies (IAUCs) </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.P13D3848L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.P13D3848L">Determining the Location, Number Density and Temporal Evolution of Streams of Hazardous Near-Earth Objects Using the Magnetic Signatures Produced in Destructive Collisions</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Lai, H.; Russell, C. T.; Wei, H.; Delzanno, G. L.; Connors, M. G. 2014-12-01 Near-Earth objects (NEOs) of tens of meters in diameter are difficult to detect by optical methods from the Earth but they result in the most damage per year. Many of these bodies are produced in non-destructive collisions with larger well-characterized NEOs. After generation, the debris spreads forward and backward in a cocoon around the orbit of the parent body. Thereafter, scattering will occur due to gravitational perturbations when the debris stream passes near a planet even when the parent body has no such close approaches. Therefore "safe" NEOs which have no close encounters to the Earth for thousands of years may be accompanied by potentially hazardous co-orbiting debris. We have developed a technique to identify co-orbiting debris by detecting the magnetic signature produced when some of the debris suffers destructive collisions with meteoroids, which are numerous and can be as small as tens of centimeters in diameter. Clouds of nanoscale dust/gas particles released in such collisions can interact coherently with the solar wind electromagnetically. The resultant magnetic perturbations are readily identified when they pass spacecraft equipped with magnetometers. We can use such observations to obtain the spatial and size distribution as well as temporal variation of the debris streams. A test of this technique has been performed and debris streams both leading and trailing asteroid 138175 have been identified. There is a finite spread across the original orbit and most of the co-orbitals were tens of meters in diameter before the disruptive collisions. We estimate that there were tens of thousands of such co-orbiting objects, comprising only 1% of the original mass of the parent asteroid but greatly increasing the impact hazard. A loss of the co-orbitals since 1970s has been inferred from observations with a decay time consistent with that calculated from the existing collisional model [Grün et al., 1985]. Therefore disruptive collisions are the main loss mechanism of the co-orbiting debris associated with 138175. In summary, our technique helps us to identify which NEOs are accompanied by hazardous debris trails. Although our technique provides only the statistical properties, it indicates where high resolution optical surveys should be obtained in order to identify and track specific hazardous bodies. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012DPS....4411101A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012DPS....4411101A">The Near-Earth Object Human Space Flight Accessible Targets Study (NHATS) List of Near-Earth Asteroids: Identifying Potential Targets for Future Exploration</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Abell, Paul; Barbee, B. W.; Mink, R. G.; Adamo, D. R.; Alberding, C. M.; Mazanek, D. D.; Johnson, L. N.; Yeomans, D. K.; Chodas, P. W.; Chamberlin, A. B.; Benner, L. A. M.; Drake, B. G.; Friedensen, V. P. 2012-10-01 Introduction: Much attention has recently been focused on human exploration of near-Earth asteroids (NEAs). Detailed planning for deep space exploration and identification of potential NEA targets for human space flight requires selecting objects from the growing list of known NEAs. NASA therefore initiated the Near-Earth Object Human Space Flight Accessible Target Study (NHATS), which uses dynamical trajectory performance constraints to identify potentially accessible NEAs. Accessibility Criteria: Future NASA human space flight capability is being defined while the Orion Multi-Purpose Crew Vehicle and Space Launch System are under development. Velocity change and mission duration are two of the most critical factors in any human spaceflight endeavor, so the most accessible NEAs tend to be those with orbits similar to Earth’s. To be classified as NHATS-compliant, a NEA must offer at least one round-trip trajectory solution satisfying purposely inclusive constraints, including total mission change in velocity ≤ 12 km/s, mission duration ≤ 450 days (with at least 8 days at the NEA), Earth departure between Jan 1, 2015 and Dec 31, 2040, Earth departure C3 ≤ 60 km2/s2, and Earth return atmospheric entry speed ≤ 12 km/s. Monitoring and Updates: The NHATS list of potentially accessible targets is continuously updated as NEAs are discovered and orbit solutions for known NEAs are improved. The current list of accessible NEAs identified as potentially viable for future human exploration under the NHATS criteria is available to the international community via a website maintained by NASA’s NEO Program Office (http://neo.jpl.nasa.gov/nhats/). This website also lists predicted optical and radar observing opportunities for each NHATS-compliant NEA to facilitate acquisition of follow-up observations. Conclusions: This list of NEAs will be useful for analyzing robotic mission opportunities, identifying optimal round trip human space flight trajectories, and highlighting attractive objects of interest for future ground-based observation opportunities. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008Icar..198..284Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008Icar..198..284Z">The orbit and size distribution of small Solar System objects orbiting the Sun interior to the Earth's orbit</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Zavodny, Maximilian; Jedicke, Robert; Beshore, Edward C.; Bernardi, Fabrizio; Larson, Stephen 2008-12-01 We present the first observational measurement of the orbit and size distribution of small Solar System objects whose orbits are wholly interior to the Earth's (Inner Earth Objects, IEOs, with aphelion <0.983 AU). We show that we are able to model the detections of near-Earth objects (NEO) by the Catalina Sky Survey (CSS) using a detailed parameterization of the CSS survey cadence and detection efficiencies as implemented within the Jedicke et al. [Jedicke, R., Morbidelli, A., Spahr, T., Petit, J.M., Bottke, W.F., 2003. Icarus 161, 17-33] survey simulator and utilizing the Bottke et al. [Bottke, W.F., Morbidelli, A., Jedicke, R., Petit, J.-M., Levison, H.F., Michel, P., Metcalfe, T.S., 2002. Icarus 156, 399-433] model of the NEO population's size and orbit distribution. We then show that the CSS detections of 4 IEOs are consistent with the Bottke et al. [Bottke, W.F., Morbidelli, A., Jedicke, R., Petit, J.-M., Levison, H.F., Michel, P., Metcalfe, T.S., 2002. Icarus 156, 399-433] IEO model. Observational selection effects for the IEOs discovered by the CSS were then determined using the survey simulator in order to calculate the corrected number and H distribution of the IEOs. The actual number of IEOs with H<18 (21) is 36±26 ( 530±240) and the slope of the H magnitude distribution ( ∝10) for the IEOs is α=0.44-0.22+0.23. The slope is consistent with previous measurements for the NEO population of α=0.35±0.02 [Bottke, W.F., Morbidelli, A., Jedicke, R., Petit, J.-M., Levison, H.F., Michel, P., Metcalfe, T.S., 2002. Icarus 156, 399-433] and α=0.39±0.013 [Stuart, J.S., Binzel, R.P., 2004. Icarus 170, 295-311]. Based on the agreement between the predicted and observed IEO orbit and absolute magnitude distributions there is no indication of any non-gravitational effects (e.g. Yarkovsky, tidal disruption) affecting the known IEO population. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018LPICo2063.3140D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018LPICo2063.3140D">Exploration of Near-Earth Objects from the Deep Space Gateway</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Dunham, D. W.; Stakkestad, K.; Vedder, P.; McAdams, J.; Horsewood, J.; Genova, A. L. 2018-02-01 The paper will show how clever use of orbital dynamics can lower delta-V costs to enable scientifically interesting missions. The high-energy Deep Space Gateway orbits can be used to reach NEOs, a trans node for crews, or to deploy small sats. Examples are given. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000DPS....32.1408R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000DPS....32.1408R">TMAP: A NEO follow-up program utilizing undergraduate observers</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Ramirez, C.; Deaver, D.; Martinez, R.; Foster, J.; Kuang, L.; Ates, A.; Anderson, M.; Mijac, M.; Gillam, S.; Hicks, M. D. 2000-10-01 In the spring of 2000 we began TMAP (Table Mountain Astrometry Project), a program designed to provide timely astrometric followup of newly discovered near-Earth asteroids. Relying on undergraduate observers from the local California State Universities, we have to date been involved with the over 50 NEO and new comet discoveries. This is a significant fraction of all near-Earth asteroids discovered over the time period. All observations are performed at JPL's Table Mountain Facility near Wrightwood California using the 0.6-meter telescope equipped with a Photometrics LN cooled 1k CCD mounted at the cassegrain focus. With this system we can routinely detect objects to R=20.5. We have typically scheduled two runs per month on weekends bracketing the new moon. The student observers man the telescope are trained to select and obtain R-band images of candidates from the Minor Planet Center's NEO Confirmation Page (http://cfa-www.harvard.edu/cfa/ps/NEO/TheNEOPage.html). The astrometry is then reduced and submitted to the Minor Planet Center the following day. TMAP has proven to be an efficient way both to obtain much needed astrometric measurements of newly discovered small bodies as well as to involve undergraduate researchers in planetary research. The limiting magnitudes provided by the 0.6-meter partially fills the gap between the extremely helpful and dedicated amateur astromitrists and the followup that the NEO detection programs do themselves. This work is supported by NASA. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active">9</li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active">10</li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20030110779&hterms=migration&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dmigration','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20030110779&hterms=migration&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dmigration">Volatiles Inventory to the Inner Planets Due to Small Bodies Migration</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Marov, M. Y.; Ipatov, S. I. 2003-01-01 The concurrent processes of endogeneous and exogeneous origin are assumed to be responsible for the volatile reserves in the terrestrial planets. Volatiles inventory through collisions is rooted in orbital dynamics of small bodies including near-Earth objects (NEOs), short and long-period comets, and trans-Neptunian objects (TNOs), the latter probably supplying a large amount of Jupiter crossing objects (JCOs). Our model testifies that even a relatively small portion (approx. 0.001) of JCOs which transit to orbits with aphelia inside Jupiter's orbit (Q<4.7 AU) and reside such orbits during more than 1 Myr may contribute significantly in collisions with the terrestrial planets. The total mass of volatiles delivered to the Earth from the feeding zone of the giant planets could be greater than the mass of the Earth's oceans. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014DPS....4640305F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014DPS....4640305F">Properties of Earth's temporarily-captured flybys</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Fedorets, Grigori; Granvik, Mikael 2014-11-01 In addition to the Moon, a population of small temporarily-captured NEOs is predicted to orbit the Earth. The definition of a natural Earth satellite is that it is on an elliptic geocentric orbit within 0.03 au from the Earth. The population is further divided into temporarily-captured orbiters (TCOs, or minimoons, making at least one full revolution around the Earth in a coordinate system co-rotating with the Sun) and temporarily-captured flybys (TCFs) which fail to make a full revolution, but are temporarily on an elliptic orbit around the Earth. Only one minimoon has been discovered to date, but it is expected that next generation surveys will be able to detect these objects regularly.Granvik et al. (2012) performed an extensive analysis of the behaviour of these temporarily-captured objects. One of the main results was that at any given moment there is at least one 1-meter-diameter minimoon in orbit around the Earth. However, the results of Granvik et al. (2012) raised questions considering the NES population such as the bimodality of the capture duration distribution and a distinctive lack of test particles within Earth's Hill sphere, which requires investigating the statistical properties also of the TCF population.In this work we confirm the population characteristics for minimoons described by Granvik et al. (2012), and extend the analysis to TCFs. For the calculations we use a Bulirsch-Stoer integrator implemented in the OpenOrb software package (Granvik et al. 2009). We study, e.g., the capture statistics, residence-time distributions, and steady-state properties of TCFs. Our preliminary results indicate that TCFs may be suitable targets for asteroid-redirect missions. More detailed knowledge of the TCF population will also improve our understanding of the link between temporarily-captured objects and NEOs in general.References: Granvik et al. (2009) MPS 44(12), 1853-1861; Granvik et al. (2012) Icarus 218, 262-277. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160004674','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160004674">Circumlunar Free-Return Cycler Orbits for a Manned Earth-Moon Space Station</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Genova, Anthony L.; Aldrin, Buzz 2015-01-01 Multiple free-return circumlunar cycler orbits were designed to allow regular travel between the Earth and Moon by a manned space station. The presented cycler orbits contain circumlunar free-return "figure-8" segments and yield lunar encounters every month. Smaller space "taxi" vehicles can rendezvous with (and depart from) the cycling Earth-Moon space station to enter lunar orbit (and/or land on the lunar surface), return to Earth, or reach destinations including Earth-Moon L1 and L2 halo orbits, near-Earth objects (NEOs), Venus, and Mars. To assess the practicality of the selected orbits, relevant cycler characteristics (including (Delta)V maintenance requirements) are presented and compared. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007epsc.conf..547M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007epsc.conf..547M">A sample return mission to a pristine NEO submitted to ESA CV 2015-2025</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Michel, P.; Barucci, A. 2007-08-01 ESA Cosmic Vision 2015-2025 aims at furthering Europe's achievements in space science, for the benefit of all mankind. ESA' multinational Space Science Advisory Committee prepared the final plan, which contains a selection of themes and priorities. In the theme concerning how the Solar System works, a Near-Earth Object (NEO) sample return mission is indicated among the priorities. Indeed, small bodies, as primitive leftover building blocks of the Solar System formation process, offer clues to the chemical mixture from which the planets formed some 4.6 billion years ago. The Near Earth Objects (NEOs) are representative of the population of asteroids and dead comets and are thought to be similar in many ways to the ancient planetesimal swarms that accreted to form the planets. NEOs are thus fundamentally interesting and highly accessible targets for scientific research and space missions. A sample return space mission to a pristine NEO has thus been proposed in partnership with the Japanese Space Agency JAXA, involving a large European community of scientists. The principal objectives are to obtained crucial information about 1) the properties of the building blocks of the terrestrial planets; 2) the major events (e.g. agglomeration, heating, ... .) which ruled the history of planetesimals; 3) the properties of primitive asteroids which may contain presolar material unknown in meteoritic samples; 4) the organics in primitive materials; 5) the initial conditions and evolution history of the solar nebula; and 6) on the potential origin of molecules necessary for life. This project appears clearly to have the potential to revolutionize our understanding of primitive materials. It involves a main spacescraft which will allow the determination of important physical properties of the target (shape, mass, crater distribution . . . ) and which will take samples by a touch-and-go procedure, a Lander for in-situ investigation of the sampling site, and sampling depending on technological development and resource allocations, a re-entry capsule, and scientific payloads. We will present the mission targets, scenarios and techniques that have been proposed. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DPS....4730802R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DPS....4730802R">Asteroid Detection Results Using the Space Surveillance Telescope</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Ruprecht, Jessica D.; Ushomirsky, Gregory; Woods, Deborah F.; Viggh, Herbert E. M.; Varey, Jacob; Cornell, Mark E.; Stokes, Grant 2015-11-01 From 1998-2013, MIT Lincoln Laboratory operated a highly successful near-Earth asteroid search program using two 1-m optical telescopes located at the MIT Lincoln Laboratory Experimental Test Site (ETS) in Socorro, N.M. In 2014, the Lincoln Near-Earth Asteroid Research (LINEAR) program successfully transitioned operations from the two 1-m telescopes to the 3.5-m Space Surveillance Telescope (SST) located at Atom Site on White Sands Missile Range, N.M. This paper provides a summary of first-year performance and results for the LINEAR program with SST and provides an update on recent improvements to the moving-object pipeline architecture that increase utility of SST data for NEO discovery and improve sensitivity to fast-moving objects. Ruprecht et al. (2014) made predictions for SST NEO search productivity as a function of population model. This paper assesses the NEO search performance of SST in the first 1.5 years of operation and compares results to model predictions.This work is sponsored by the Defense Advanced Research Projects Agency and the National Aeronautics and Space Administration under Air Force Contract #FA8721-05-C-0002. The views, opinions, and/or findings contained in this article/presentation are those of the authors / presenters and should not be interpreted as representing the official views or policies of the Department of Defense or the U.S. Government. Distribution Statement A: Approved for public release, distribution unlimited. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015amos.confE..92R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015amos.confE..92R">Asteroid Detection Results Using the Space Surveillance Telescope</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Ruprecht, J.; Ushomirsky, G.; Woods, D.; Viggh, H.; Varey, J.; Cornell, M.; Stokes, G. From 1998-2013, MIT Lincoln Laboratory operated a highly successful near-Earth asteroid search program using two 1-m optical telescopes located at the MIT Lincoln Laboratory Experimental Test Site (ETS) in Socorro, N.M. In 2014, the Lincoln Near-Earth Asteroid Research (LINEAR) program successfully transitioned operations from the two 1-m telescopes to the 3.5-m Space Surveillance Telescope (SST) located at Atom Site on White Sands Missile Range, N.M. This paper provides a summary of first-year performance and results for the LINEAR program with SST and provides an update on recent improvements to the moving-object pipeline architecture that increase utility of SST data for NEO discovery and improve sensitivity to fast-moving objects. Ruprecht et al. (2014) made predictions for SST NEO search productivity as a function of population model. This paper assesses the NEO search performance of SST in the first 1.5 years of operation and compares results to model predictions. This work is sponsored by the Defense Advanced Research Projects Agency and the National Aeronautics and Space Administration under Air Force Contract #FA8721-05-C-0002. The views, opinions, and/or findings contained in this article/presentation are those of the authors / presenters and should not be interpreted as representing the official views or policies of the Department of Defense or the U.S. Government. Distribution Statement A: Approved for public release, distribution unlimited. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMIN41B0040S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMIN41B0040S">What do the data show? Fostering physical intuition with ClimateBits and NASA Earth Observations</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Schollaert Uz, S.; Ward, K. 2017-12-01 Through data visualizations using global satellite imagery available in NASA Earth Observations (NEO), we explain Earth science concepts (e.g. albedo, urban heat island effect, phytoplankton). We also provide examples of ways to explore the satellite data in NEO within a new blog series. This is an ideal tool for scientists and non-scientists alike who want to quickly check satellite imagery for large scale features or patterns. NEO analysis requires no software or plug-ins; only a browser and an internet connection. You can even check imagery and perform simple analyses from your smart phone. NEO can be used to create graphics for presentations and papers or as a first step before acquiring data for more rigorous analysis. NEO has potential application to easily explore large scale environmental and climate patterns that impact operations and infrastructure. This is something we are currently exploring with end user groups. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4831106C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4831106C">Impact detections of temporarily captured natural satellites</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Clark, David; Spurný, Pavel; Wiegert, Paul; Brown, Peter G.; Borovicha, Jiri; Tagliaferri, Ed; Shrbeny, Lukas 2016-10-01 Temporarily Captured Orbiters (TCOs) are Near-Earth Objects (NEOs) which make a few orbits of Earth before returning to heliocentric orbits. Only one TCO has been observed to date, 2006 RH120, captured by Earth for one year before escaping. Detailed modeling predicts capture should occur from the NEO population predominantly through the Sun-Earth L1 and L2 points, with 1% of TCOs impacting Earth and approximately 0.1% of meteoroids being TCOs. Although thousands of meteoroid orbits have been measured, none until now have conclusively exhibited TCO behaviour, largely due to difficulties in measuring initial meteoroid speed with sufficient precision. We report on a precise meteor observation of January 13, 2014 by a new generation of all-sky fireball digital camera systems operated in the Czech Republic as part of the European Fireball Network, providing the lowest natural object entry speed observed in decades long monitoring by networks world-wide. Modeling atmospheric deceleration and fragmentation yields an initial mass of ~5 kg and diameter of 15 cm, with a maximum Earth-relative velocity just over 11.0 km/s. Spectral observations prove its natural origin. Back-integration across observational uncertainties yields a 92 - 98% probability of TCO behaviour, with close lunar dynamical interaction. The capture duration varies across observational uncertainties from 48 days to 5+ years. We also report on two low-speed impacts recorded by US Government sensors, and we examine Prairie Network event PN39078 from 1965 having an extremely low entry speed of 10.9 km/s. In these cases uncertainties in measurement and origin make TCO designation uncertain. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004DDA....35.0707I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004DDA....35.0707I">Orbital Evolution of Jupiter-family Comets</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Ipatov, S. I.; Mather, J. C. 2004-05-01 The orbital evolution of more than 25,000 Jupiter-family comets (JFCs) under the gravitational influence of planets was studied. After 40 Myr one considered object (with initial orbit close to that of Comet 88P) got aphelion distance Q<3.5 AU, and it moved in orbits with semi-major axis a=2.60-2.61 AU, perihelion distance 1.7<q<2.2 AU, 3.1<Q<3.5 AU, eccentricity e=0.2-0.3, and inclination i=5-10 deg for 650 Myr. Another object (with initial orbit close to that of Comet 94P) moved in orbits with a=1.95-2.1 AU, q>1.4 AU, Q<2.6 AU, e=0.2-0.3, and i=9-33 deg for 8 Myr (and it had Q<3 AU for 100 Myr). So JFCs can rarely get typical asteroid orbits and move in them for Myrs. In our opinion, it can be possible that Comet 133P (Elst--Pizarro) moving in a typical asteroidal orbit was earlier a JFC and it circulated its orbit also due to non-gravitational forces. JFCs got near-Earth object (NEO) orbits more often than typical asteroidal orbits. A few JFCs got Earth-crossing orbits with a<2 AU and Q<4.2 AU and moved in such orbits for more than 1 Myr (up to tens or even hundreds of Myrs). Three considered former JFCs even got inner-Earth orbits (with Q<0.983 AU) or Aten orbits for Myrs. The probability of a collision of one of such objects, which move for millions of years inside Jupiter's orbit, with a terrestrial planet can be greater than analogous total probability for thousands other objects. Results obtained by the Bulirsch-Stoer method and by a symplectic method were mainly similar (except for probabilities of close encounters with the Sun when they were high). Our results show that the trans-Neptunian belt can provide a significant portion of NEOs, or the number of trans-Neptunian objects migrating inside solar system could be smaller than it was earlier considered, or most of 1-km former trans-Neptunian objects that had got NEO orbits disintegrated into mini-comets and dust during a smaller part of their dynamical lifetimes if these lifetimes are not small. The obtained results show that during the accumulation of the giant planets the total mass of icy bodies delivered to the Earth could be about the mass of water in Earth's oceans. Several our papers on this problem were put in http://arXiv.org/format/astro-ph/ (e.g., 0305519, 0308448). This work was supported by NASA (NAG5-10776) and INTAS (00-240). </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/22340252-fast-rotation-subkilometer-sized-near-earth-object-xa-sub','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22340252-fast-rotation-subkilometer-sized-near-earth-object-xa-sub">Fast rotation of a subkilometer-sized near-Earth object 2011 XA{sub 3}</a> <a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Urakawa, Seitaro; Ohtsuka, Katsuhito; Abe, Shinsuke 2014-05-01 We present light curve observations and their multiband photometry for near-Earth object (NEO) 2011 XA{sub 3}. The light curve has shown a periodicity of 0.0304 ± 0.0003 days (= 43.8 ± 0.4 minutes). The fast rotation shows that 2011 XA{sub 3} is in a state of tension (i.e., a monolithic asteroid) and cannot be held together by self-gravitation. Moreover, the multiband photometric analysis indicates that the taxonomic class of 2011 XA{sub 3} is S-complex, or V-type. Its estimated effective diameter is 225 ± 97 m (S-complex) and 166 ± 63 m (V-type), respectively. Therefore, 2011 XA{sub 3} is a candidatemore » for the second-largest, fast-rotating, monolithic asteroid. Moreover, the orbital parameters of 2011 XA{sub 3} are apparently similar to those of NEO (3200) Phaethon, but F/B-type. We computed the orbital evolutions of 2011 XA{sub 3} and Phaethon. However, the results of the computation and distinct taxonomy indicate that neither of the asteroids is of common origin.« less </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Ap%26SS.361...10T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Ap%26SS.361...10T">Capture of near-Earth objects with low-thrust propulsion and invariant manifolds</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Tang, Gao; Jiang, Fanghua 2016-01-01 In this paper, a mission incorporating low-thrust propulsion and invariant manifolds to capture near-Earth objects (NEOs) is investigated. The initial condition has the spacecraft rendezvousing with the NEO. The mission terminates once it is inserted into a libration point orbit (LPO). The spacecraft takes advantage of stable invariant manifolds for low-energy ballistic capture. Low-thrust propulsion is employed to retrieve the joint spacecraft-asteroid system. Global optimization methods are proposed for the preliminary design. Local direct and indirect methods are applied to optimize the two-impulse transfers. Indirect methods are implemented to optimize the low-thrust trajectory and estimate the largest retrievable mass. To overcome the difficulty that arises from bang-bang control, a homotopic approach is applied to find an approximate solution. By detecting the switching moments of the bang-bang control the efficiency and accuracy of numerical integration are guaranteed. By using the homotopic approach as the initial guess the shooting function is easy to solve. The relationship between the maximum thrust and the retrieval mass is investigated. We find that both numerically and theoretically a larger thrust is preferred. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014acm..conf...97C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014acm..conf...97C">A powerful new southern hemisphere survey for near-Earth objects</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Christensen, E.; Lister, T.; Larson, S.; Gibbs, A.; Grauer, A.; Hill, R.; Johnson, J.; Kowalski, R.; Sanders, R.; Shelly, F. 2014-07-01 For nearly a decade, the Catalina Sky Survey (CSS) operated the Siding Spring Survey (SSS) in partnership with the Australian National University. The SSS was the only professional, full-time NEO survey in the Southern Hemisphere during this period. The SSS ceased operations in July of 2013, and the lack of a full-time, state-of-the-art survey in the Southern Hemisphere leaves a significant blind spot in NASA's ongoing effort to identify and track near-Earth objects (NEOs) that may pose a hazard to the Earth, or that may be appropriate destinations for robotic or human missions. The CSS and the Las Cumbres Observatory Global Telescope Network (LCOGT) are partnering to fill this gap, by rapidly building, deploying and operating a network of three dedicated 1.0-meter survey telescopes at Cerro Tololo, one of the premiere astronomical sites in the Southern Hemisphere. The partnership between CSS and LCOGT provides a fast-track, low-risk, and cost-effective survey capability that will be fully dedicated to the NEO discovery effort. The first of three survey telescopes will be operational ˜18 months after the start of funding, with the second and third telescopes coming online within an additional ˜12 months. Our joint survey will be a powerful new NEO survey capability. The telescopes are based on the field-tested LCOGT 1.0-m design, modified to feature a faster f/1.8 primary and a prime focus camera that will deliver an 8.6 deg^2 field of view (FOV), with a resolution of 1.0 arcseconds per pixel. The three co-located telescopes will offer the operational flexibility to survey together (acting as a 1.7-m telescope), or separately (effectively delivering a 25+ deg^2 FOV), and will have no competing science goals to compromise from the primary mission of NEO discovery. The telescopes will be robotically operated, and the data will be processed, validated, and reported in near real-time from the CSS headquarters in Tucson. Same-night and subsequent night astrometric follow-up observations will be carried out on the LCOGT network, which includes two 2.0-m and nine 1.0-m telescopes at 5 sites in both hemispheres. We calculate figures of merit (FOM) for this and other NEO survey systems, based on clear aperture, field of view, optical throughput, focal-plane fill factor and open-shutter efficiency. Our new survey program will be among the most powerful NEO survey systems in operation once deployed, with a FOM approximately 25 × larger than the SSS, larger than all CSS assets in Arizona combined, and larger than Pan-STARRS 1. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AdAnS.140..440P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AdAnS.140..440P">A New Approach on the Long Term Dynamics of NEO's Under Yarkovsky Effect.</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Peláez, Jesús; Urrutxua, Hodei; Bombardelli, Claudio; Perez-Grande, Isabel 2011-12-01 A classical approach to the many-body problem is that of using special perturbation methods. Nowadays and due to the availability of high-speed computers is an essential tool in Space Dynamics which exhibits a great advantage: it is applicable to any orbit involving any number of bodies and all sorts of astrodynamical problems, especially when these problems fall into regions in which general perturbation theories are absent. One such case is, for example, that Near Earth Objects (NEO's) dynamics. In this field, the Group of Tether Dynamics of UPM (GDT) has developed a new regularisation scheme - called DROMO - which is characterised by only 8 ODE. This new regularisation scheme allows a new approach to the dynamics of NEO's in the long term, specially appropriated to consider the influence of the anisotropic thermal emission (Yarkovsky and YORP effects) on the dynamics. A new project, called NEODROMO, has been started in GDT that aims to provide a reliable tool for the long term dynamics of NEO's. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001DPS....33.1407J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001DPS....33.1407J">The Next Giant Leap: Human Exploration and Utilization of NEOs</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Jones, T. D.; Vilas, F.; Love, S.; Hack, K.; Gefert, L.; Sykes, M. V.; Lewis, J. S.; Jedicke, R.; Davis, D.; Hartmann, W. K.; Farquhar, R.; McFadden, L.; Durda, D. 2001-11-01 Planetary science plays a unique role as the pathfinder for future human space activities beyond the International Space Station. It can also provide the rationale for the first human departure from LEO since the Apollo program. We are examining the potential for human missions to small near-Earth objects (typically tens of meters), passing close by the Earth-Moon system with very low delta-v. A preliminary estimate suggests there may be many thousands of these objects, raising the possibility of number of launch opportunities each year. To demonstrate feasibility, we have simulated a mission to 1991 VG during 1991/1992 when it passed within 0.004 AU of the Earth. This mission takes a total of 60 days, including a 30 day stay time at the asteroid. The accessibility of these targets may provide an opportunity to develop and test systems needed for longer duration interplanetary missions to Mars, and to engage in precursor space resource utilization activities. Early discovery, orbit determination, and target characterization should be pursued and spacebased and groundbased systems that would be needed assessed. Crewed missions would be preceded by robotic probes to test acquisition, rendezvous, and local operations while returning significant new science from target objects. As we look beyond ISS over the next decade, we must reinvigorate a mutually supportive relationship between our human space and solar system exploration goals. The scientific and exploration rationale for sending humans to NEOs must be mature to meet NASA's decision making window, now opening, for operations beyond near-Earth space. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/22370281-ne-abundance-ratio-interstellar-medium-from-ibex-lo-observations','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22370281-ne-abundance-ratio-interstellar-medium-from-ibex-lo-observations"></a> <a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Park, J.; Kucharek, H.; Möbius, E. In this paper we report on a two-year study to estimate the Ne/O abundance ratio in the gas phase of the local interstellar cloud (LIC). Based on the first two years of observations with the Interstellar Boundary Explorer, we determined the fluxes of interstellar neutral (ISN) O and Ne atoms at the Earth's orbit in spring 2009 and 2010. A temporal variation of the Ne/O abundance ratio at the Earth's orbit could be expected due to solar cycle-related effects such as changes of ionization. However, this study shows that there is no significant change in the Ne/O ratio at themore » Earths orbit from 2009 to 2010. We used time-dependent survival probabilities of the ISNs to calculate the Ne/O abundance ratio at the termination shock. Then we estimated the Ne/O abundance ratio in the gas phase of the LIC with the use of filtration factors and the ionization fractions. From our analysis, the Ne/O abundance ratio in the LIC is 0.33 ± 0.07, which is in agreement with the abundance ratio inferred from pickup-ion measurements.« less </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120001818','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120001818">The Near-Earth Object Human Space Flight Accessible Targets Study (NHATS) List of Near-Earth Asteroids: Identifying Potential Targets for Future Exploration</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Abell, Paul A.; Barbee, B. W.; Mink, R. G.; Alberding, C. M.; Adamo, D. R.; Mazanek, D. D.; Johnson, L. N.; Yeomans, D. K.; Chodas, P. W.; Chamberlin, A. B.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20120001818'); toggleEditAbsImage('author_20120001818_show'); toggleEditAbsImage('author_20120001818_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20120001818_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20120001818_hide"> 2012-01-01 Over the past several years, much attention has been focused on the human exploration of near-Earth asteroids (NEAs). Two independent NASA studies examined the feasibility of sending piloted missions to NEAs [1, 2], and in 2009, the Augustine Commission identified NEAs as high profile destinations for human exploration missions beyond the Earth-Moon system [3]. More recently the current U.S. presidential administration directed NASA to include NEAs as destinations for future human exploration with the goal of sending astronauts to a NEA in the mid to late 2020s. This directive became part of the official National Space Policy of the United States of America as of June 28, 2010 [4]. Detailed planning for such deep space exploration missions and identifying potential NEAs as targets for human spaceflight requires selecting objects from the ever growing list of newly discovered NEAs. Hence NASA developed and implemented the Near-Earth Object (NEO) Human Space Flight (HSF) Accessible Target Study (NHATS), which identifies potential candidate objects on the basis of defined dynamical trajectory performance constraints. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4830503F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4830503F">Scout: orbit analysis and hazard assessment for NEOCP objects</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Farnocchia, Davide; Chesley, Steven R.; Chamberlin, Alan B. 2016-10-01 It typically takes a few days for a newly discovered asteroid to be officially recognized as a real object. During this time, the tentative discovery is published on the Minor Planet Center's Near-Earth Object Confirmation Page (NEOCP) until additional observations confirm that the object is a real asteroid rather than an observational artifact or an artificial object. Also, NEOCP objects could have a limited observability window and yet be scientifically interesting, e.g., radar and lightcurve targets, mini-moons (temporary Earth captures), mission accessible targets, close approachers or even impactors. For instance, the only two asteroids discovered before an impact, 2008 TC3 and 2014 AA, both reached the Earth less than a day after discovery. For these reasons we developed Scout, an automated system that provides an orbital and hazard assessment for NEOCP objects within minutes after the observations are available. Scout's rapid analysis increases the chances of securing the trajectory of interesting NEOCP objects before the ephemeris uncertainty grows too large or the observing geometry becomes unfavorable. The generally short observation arcs, perhaps only a few hours or even less, lead severe degeneracies in the orbit estimation process. To overcome these degeneracies Scout relies on systematic ranging, a technique that derives possible orbits by scanning a grid in the poorly constrained space of topocentric range and range rate, while the plane-of-sky position and motion are directly tied to the recorded observations. This scan allows us to derive a distribution of the possible orbits and in turn identify the NEOCP objects of most interest to prioritize followup efforts. In particular, Scout ranks objects according to the likelihood of an impact, estimates the close approach distance, the Earth-relative minimum orbit intersection distance and v-infinity, and computes scores to identify objects more likely to be an NEO, a km-sized NEO, a Potentially Hazardous Asteroid, and those on a geocentric orbit. Moreover, Scout provides an ephemeris service that makes use of the statistical information to support observers in their followup efforts. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997AAS...190.2103B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997AAS...190.2103B">Introducing the Benson Prize for Discovery Methods of Near Earth Objects by Amateurs</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Benson, J. W. 1997-05-01 The Benson Prize Sponsored by Space Development Corporation The Benson Prize for Discovery Methods of Near Earth Objects by Amateurs is an annual competition which awards prizes to the best proposed methods by which amateur astronomers may discover such near earth objects as asteroids and comet cores. The purpose of the Benson Prize is to encourage the discovery of near earth objects by amateur astronomers. The utilization of valuable near earth resources can provide many new jobs and economic activities on earth, while also creating many new opportunities for opening up the space frontier. The utilization of near earth resources will significantly contribute to the lessening of environmental degradation on the Earth caused by mining and chemical leaching operations required to exploit the low grade ores now remaining on Earth. In addition, near earth objects pose grave dangers for life on earth. Discovering and plotting the orbits of all potentially dangerous near earth objects is the first and necessary step in protecting ourselves against the enormous potential damage possible from near earth objects. With the high quality, large size and low cost of todays consumer telescopes, the rapid development of powerful, high resolution and inexpensive CCD cameras, and the proliferation of inexpensive software for todays powerful home computers, the discovery of near earth objects by amateur astronomers is more attainable than ever. The Benson Prize is sponsored by the Space Development Corporation, a space resource exploration and utilization company. In 1997 one prize of \\500 will be awarded to the best proposed method for the amateur discovery of NEOs, and in each of the four following years, Prizes of \\500, \\250 and \\100 will be awarded. Prizes for the actual discovery of Near Earth Asteroids will be added in later years. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020039968&hterms=energy+civilization&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Denergy%2Bcivilization','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020039968&hterms=energy+civilization&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Denergy%2Bcivilization">NASA Space Missions to Asteroids: Protecting the Earth from NEO Impacts</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Morrison, David; Berry, William E. (Technical Monitor) 1996-01-01 There is now a general recognition of the hazard of impacts on Earth by comets and asteroids, but there is yet no consensus concerning international actions that should be taken to protect the planet from such impacts. An essential step in the analysis of the situation involves estimating the relative hazard posed by comets and asteroids of different sizes and orbits. All recent studies agree that the larger impacts pose the greater danger, and that our primary concern from the perspective of total risk should be on impacts that are large enough to cause global ecological catastrophe. These global catastrophes are also of special interest, since they (alone among natural disasters) have the potential to destroy civilization. Studies of the sensitivity of the Earth's environment suggest that the energy threshold energy for causing a global catastrophe is at about 1 million megatons, corresponding to impactor diameters of 1.5 to 2 km. This information leads naturally to a strategy of concentrating on the larger NEOs, say those 1 km or more in diameter. This is the rationale for the Spaceguard Survey, which must be the highest priority in mitigation efforts. The second question concerns the value of developing standing defensive systems that could deflect or destroy an incoming NEO. In the case of the asteroids larger than 1 km in diameter, no such system is needed, since there will be ample time (at least several decades) between the discovery of the threatening object by Spaceguard and the requirement to take action against it. In the case of objects smaller than 1 km diameter, development of defensive systems is not cost-effective; there are many greater dangers to persons and property that are much more urgent. Only in the case of large long-period comets is there a rationale for standing defense systems. The question is also raised whether the risks inherent in developing and maintaining a defense system might be greater than the impact risks it is intended to guard against. These and related issues are the focus of much current international debate on defense of the planet against NEO impacts. Meanwhile, the most critical issue remains the expansion of the telescopic search for NEOs. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017DPS....4911707L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017DPS....4911707L">Recent Advances and Achievements at The Catalina Sky Survey</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Leonard, Gregory J.; Christensen, Eric J.; Fuls, Carson; Gibbs, Alex; Grauer, Al; Johnson, Jess A.; Kowalski, Richard; Larson, Stephen M.; Matheny, Rose; Seaman, Rob; Shelly, Frank 2017-10-01 The Catalina Sky Survey (CSS) is a NASA-funded project fully dedicated to discover and track near-Earth objects (NEOs). Since its founding nearly 20 years ago CSS remains at the forefront of NEO surveys, and recent improvements in both instrumentation and software have increased both survey productivity and data quality. In 2016 new large-format (10K x 10K) cameras were installed on both CSS survey telescopes, the 1.5-m reflector and the 0.7-m Schmidt, increasing the field of view, and hence nightly sky coverage by 4x and 2.4x respectively. The new cameras, coupled with improvements in the reduction and detection pipelines, and revised sky-coverage strategies have yielded a dramatic upward trend of NEO discovery rates. CSS has also developed a custom adaptive queue manager for scheduling NEO follow-up astrometry using a remotely operated and recently renovated 1-m Cassegrain reflector telescope, improvements that have increased the production of follow-up astrometry for newly discovered NEOs and arc extensions for previously discovered objects by CSS and other surveys. Additionally, reprocessing of archival CSS data (which includes some 46 million individual astrometric measurements) through the new reduction and detection pipeline will allow for improved orbit determinations and increased arc extensions for hundreds of thousands of asteroids. Reprocessed data will soon feed into a new public archive of CSS images and catalog data products made available through NASA’s Planetary Data System (PDS). For the future, CSS is working towards improved NEO follow-up capabilities through a combination of access to larger telescopes, instrument upgrades and follow-up scheduling tools. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active">10</li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active">11</li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150018049','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150018049">A Free-Return Earth-Moon Cycler Orbit for an Interplanetary Cruise Ship</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Genova, Anthony L.; Aldrin, Buzz 2015-01-01 A periodic circumlunar orbit is presented that can be used by an interplanetary cruise ship for regular travel between Earth and the Moon. This Earth-Moon cycler orbit was revealed by introducing solar gravity and modest phasing maneuvers (average of 39 m/s per month) which yields close-Earth encounters every 7 or 10 days. Lunar encounters occur every 26 days and offer the chance for a smaller craft to depart the cycler and enter lunar orbit, or head for a Lagrange point (e.g., EM-L2 halo orbit), distant retrograde orbit (DRO), or interplanetary destination such as a near-Earth object (NEO) or Mars. Additionally, return-to-Earth abort options are available from many points along the cycling trajectory. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ATel.5311....1H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ATel.5311....1H">Broadband Photometry Of The Potentially Asteroid 277475 (2005 WK4) and Corrected 52762 (1998 MT24) Colors.</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Hicks, M.; Buratt, B.; Carcione, A.; Borlase, R. 2013-08-01 The Near-Earth Object (NEO) 277475 (2005 WK4) was discovered by the Siding Spring Survey (MPEC 2005-W79) on November 27, 2005. With a Minimum Orbit Intersection Distance (MOID) of 0.004 AU and absolute magnitude H_V=20.1 mag, this object has been designated a Potentially Hazardous Asteroid (PHA) by the Minor Planet Center. The asteroid made an Earth close-approach of 0.021 AU on August 09.2, 2013 and was extensively imaged by the JPL Planetary Radar Team ( http://www.jpl.nasa.gov/news/news.php?release=2013-254 ). </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017DPS....4911008B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017DPS....4911008B">NEOShield-2 Project: Final Results on Compositional Characterization of small NEOs</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Barucci, Maria Antonieta; Perna, Davide; Fornasier, Sonia; Doressoundiram, Alain; Lantz, Cateline; Popescu, Marcel; Merlin, Frederic; Fulchignoni, Marcello 2017-10-01 NEOShield-2 project was selected in the framework of the European Commission H2020 program in answer to the call for “Access technologies and characterisation for Near Earth Objects (NEOs)”. NEOShield-2 project (2015-2017) is a follow-up of the first NEOShield (2012-2015) and includes 11 European Institutions and Industries. The main objectives of NEOShield-2 project are: i) technological development on techniques and instruments needed for GNC for possible asteroid missions and ii) characterization of NEOs of small sizes.Our team at LESIA is the leader of the entire observational program which involved complementary techniques to provide physical and compositional characterization of NEOs. Priority has been given to potential space-mission targets, optimized for mitigation or exploration missions. In this framework an agreement with the European Southern Observatory was signed to obtain Guaranteed Time Observations at the 3.6-meter NTT with an allocation of 30 nights to characterize by spectroscopy the composition of the smaller asteroids. The objects with an absolute magnitude larger than 20 were selected, with a priority for the very small newly discovered objects.We obtained more than 170 new spectra of NEOs. The observations were performed with EFOSC2 instrument. We covered the wavelength interval 0.4-0.92 microns, with a resolution of R=~200. The observed asteroids include 29 asteroids with diameters smaller than 100 meters and 71 with diameters between 100 and 300 m.The taxonomic type has been assigned for 137 individual objects. Our results on NEO mineralogical compositions provide a body of reference data directly applicable to the design and development of mitigation-relevant space missions. Within our survey, we found eight D-types with ΔV < 7 km/s, four of which with ΔV < 6 km/s. Among these, 2009 DL46 and (52381) 1993 HA, with a ΔV below 5.5 km/s and a diameter large enough to allow spacecraft operations in their proximity, represent the best candidates currently known for a sample-return mission to a D-type primitive asteroid.Acknowledgments: The authors acknowledge the NEOShield-2 funding by European Commission Horizon 2020 program (contract No. PROTEC-2-2014-640351). </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017yCat..17920030M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017yCat..17920030M">VizieR Online Data Catalog: NEOWISE magnitudes for near-Earth objects (Mainzer+, 2014)</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Mainzer, A.; Bauer, J.; Cutri, R. M.; Grav, T.; Masiero, J.; Beck, R.; Clarkson, P.; Conrow, T.; Dailey, J.; Eisenhardt, P.; Fabinsky, B.; Fajardo-Acosta, S.; Fowler, J.; Gelino, C.; Grillmair, C.; Heinrichsen, I.; Kendall, M.; Kirkpatrick, J. D.; Liu, F.; Masci, F.; McCallon, H.; Nugent, C. R.; Papin, M.; Rice, E.; Royer, D.; Ryan, T.; Sevilla, P.; Sonnett, S.; Stevenson, R.; Thompson, D. B.; Wheelock, S.; Wiemer, D.; Wittman, M.; Wright, E.; Yan, L. 2017-04-01 Regular survey operations, including the moving object processing pipeline, began on 2013 December 23; the first new NEO was discovered 6 days later. The NEOWISE operational cadence remains identical to that employed during the prime mission (Wright et al. 2010AJ....140.1868W; Heinrichsen & Wright 2006SPIE.6270E..1CH). The telescope scans continuously along great circles with approximately constant ecliptic longitude, while a scan mirror freezes the sky on the focal planes for 9.9 s and returns to its starting position 1.1 s later. While the sky is fixed on the focal planes, simultaneous exposures are collected in the W1 and W2 bands through the use of beamsplitters every 11 s with an exposure time of 7.7 s. Based on its present rate of NEO observations, over the course of its three year mission, NEOWISE is expected to observe ~2000 NEOs, roughly 700-800 of which will be detected in single-exposure images, with the remainder being recoverable through stacking. (1 data file). </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002MmSAI..73..768T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002MmSAI..73..768T">Data archiving and network system of Bisei Spaceguard center</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Terazono, J.-Y.; Asami, A.; Asher, D.; Hashimoto, N.; Nakano, S.; Nishiyama, K.; Oshima, Y.; Umehara, H.; Urata, T.; Yoshikawa, M.; Isobe, S. 2002-09-01 Bisei Spaceguard Center, Japan's first facility for observations of space debris and Near-Earth Objects (NEOs), will produce large amounts of data. In this paper, we describe details of the data transfer and processing system we are now developing. Also we present a software system devoted to the discovery of asteroids mainly by high school students. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017DPS....4910002G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017DPS....4910002G">Debiased estimates for NEO orbits, absolute magnitudes, and source regions</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Granvik, Mikael; Morbidelli, Alessandro; Jedicke, Robert; Bolin, Bryce T.; Bottke, William; Beshore, Edward C.; Vokrouhlicky, David; Nesvorny, David; Michel, Patrick 2017-10-01 The debiased absolute-magnitude and orbit distributions as well as source regions for near-Earth objects (NEOs) provide a fundamental frame of reference for studies on individual NEOs as well as on more complex population-level questions. We present a new four-dimensional model of the NEO population that describes debiased steady-state distributions of semimajor axis (a), eccentricity (e), inclination (i), and absolute magnitude (H). We calibrate the model using NEO detections by the 703 and G96 stations of the Catalina Sky Survey (CSS) during 2005-2012 corresponding to objects with 17<H<25. The modeling approach improves upon the methodology originally developed by Bottke et al. (2000, Science 288, 2190) in that we allow the power-law slope of the H-frequency distribution to change as a function of H and we carry out the fitting in an absolute sense using the biases computed for CSS (Jedicke et al. 2016, Icarus 266, 173). The model makes use of six source regions or escape routes from the main asteroid belt as identified by Granvik et al. (2017, A&A 598, A52) in addition to Jupiter-family comets: Hungaria and Phocaea asteroids, and main-belt asteroids escaping through the ν6, 3:1J, 5:2J and 2:1J resonance complexes. We account for the destruction of asteroids with small perihelion distances (Granvik et al. 2016, Nature 530, 303) by fitting a penalty function in perihelion distance. Our model accurately reproduces the observed distribution of NEOs and the predicted numbers, particularly for the larger NEOs, are in agreement with other contemporary estimates. Our model also provides updated estimates for the likelihood of the various source regions and escape routes as a function of NEO (a,e,i,H) parameters. We present the model and its predictions, and discuss them in the context of other contemporary estimates. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014acm..conf..533T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014acm..conf..533T">On the existence of near-Earth-object meteoroid complexes producing meteorites</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Trigo-Rodriguez, J.; Madiedo, J.; Williams, I. 2014-07-01 It is generally thought that meteorites are formed as a result of collisions within the main belt of asteroids [1]. They are delivered onto Earth-crossing orbits because of the effects of orbital resonances, primarily with Jupiter. About 15 meteorites are known where their passage through the atmosphere was observed and recorded, allowing the parameters of the pre-encounter orbit to be derived [2]. The cosmic-ray-exposure ages (CREAs) are suggesting that most meteorites have been exposed to cosmic rays for tens of millions of years (Myrs) [3], re-enforcing the belief that the process of modifying the orbit from being near-circular in the main belt to highly elliptical as an Earth-crossing orbit was a gradual process like the effects of resonance. However, there is growing evidence that some meteorite could originate directly from the near-Earth-object (NEO) population. A good example of this is the recent discovery of rare primitive groups in the Antarctic, an example being Elephant Moraine (EET) 96026: a C4/5 carbonaceous chondrite with a measured cosmic ray exposure age of only 0.28 Ma [4]. Here, we focus on recent dynamic links that have been established between meteorite-dropping bolides and NEOs that support the idea of short-life meteoroid streams that can generate meteoroids on Earth. The fact that such streams can exist allows rocky material from potentially-hazardous asteroids (PHA) to be sampled and investigated in the laboratory. The existence of meteoroid streams capable of producing meteorites has been proposed following the determination of accurate meteoroid orbits of fireballs obtained by the Canadian Meteorite Observation and Recovery Project (MORP) [5]. Some asteroids in the Earth's vicinity are undergoing both dynamical and collisional evolution on very short timescales [6]. Many of these objects are crumbly bodies that originated from the collisions between main-belt asteroids during their life-time. An obvious method of forming these complexes is fracturing. Many asteroids are known to be rubble piles and such structures can be unstable during a close approach to a planet due to tidal forces. The irregular shape of many fast-rotators can allow the YORP effect to increase the spin rate, also leading to fracturing [7]. The escape speed from a fragmenting asteroid is considerably smaller than the orbital velocity so a large amount of the initial mass can be ejected. The fragmentation process is likely to produce many metre-sized rocks as well as few tens of meters fragmental asteroids that could form a complex of fragments, all moving on nearly identical orbits. The lifetime of such orbital complexes is quite short (few tens of thousand of years) as consequence of planetary perturbations[8], except perhaps for those cases exhibiting orbits with high inclination, where lifetimes can be considerably higher [9]. Catastrophic disruptions in the main asteroid belt have been extensively studied, but little is known about the relevance of the process in the NEO population. The Spanish Fireball Network (SPMN) regularly monitors the skies and is obtaining evidence that NEO complexes can be a source of meteorites. By performing backward integrations of meteoroid orbits and NEO candidates, previously identified by using our ORAS software to compute several orbital similarity criteria, we have identified several complexes associated with NEOs of chondritic nature [10-12] and even one, 2012 XJ_{112} of likely achondritic nature [13]. Another recent example was probably the Feb 15th, 2013 Chelyabinsk superbolide. The meteorites recovered were shocked to a very high level [14,15], and the ˜19-meter-diameter Chelyabinsk NEA was probably a monolithic single stone produced from its presumable progenitor, the 2.2 km in diameter asteroid (86039) [16]. This association should, however, be tested by performing backward integrations of both orbits. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012DPS....4421516L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012DPS....4421516L">The LCOGT Network for Solar System Science</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Lister, Tim 2012-10-01 Las Cumbres Observatory Global Telescope (LCOGT) network is a planned homogeneous network of over 35 telescopes at 6 locations in the northern and southern hemispheres. This network is versatile and designed to respond rapidly to target of opportunity events and also to do long term monitoring of slowly changing astronomical phenomena. The global coverage of the network and the apertures of telescope available make LCOGT ideal for follow-up and characterization of Solar System objects (e.g. asteroids, Kuiper Belt Objects, comets, Near-Earth Objects (NEOs)) and ultimately for the discovery of new objects. Currently LCOGT is operating the two 2m Faulkes Telescopes at Haleakala, Maui and Siding Spring Observatory, Australia and in March 2012 completed the install of the first member of the new 1m telescope network at McDonald Observatory, Texas. Further deployments of six to eight 1m telescopes to CTIO in Chile, SAAO in South Africa and Siding Spring Observatory are expected in late 2012-early 2013. I am using the growing LCOGT network to confirm newly detected NEO candidates produced by PanSTARRS (PS1) and other sky surveys and to obtain follow-up astrometry and photometry for radar-targeted objects. I have developed an automated system to retrieve new PS1 NEOs, compute orbits, plan observations and automatically schedule them for follow-up on the robotic telescopes of the LCOGT Network. In the future, LCOGT has proposed to develop a Minor Planet Investigation Project (MPIP) that will address the existing lack of resources for minor planet follow-up, takes advantage of ever-increasing new datasets, and develops a platform for broad public participation in relevant scientific exploration. We plan to produce a cloud-based Solar System investigation environment, a citizen science project (AgentNEO), and a cyberlearning environment, all under the umbrella of MPIP. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011ApJ...731...53M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011ApJ...731...53M">Preliminary Results from NEOWISE: An Enhancement to the Wide-field Infrared Survey Explorer for Solar System Science</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Mainzer, A.; Bauer, J.; Grav, T.; Masiero, J.; Cutri, R. M.; Dailey, J.; Eisenhardt, P.; McMillan, R. S.; Wright, E.; Walker, R.; Jedicke, R.; Spahr, T.; Tholen, D.; Alles, R.; Beck, R.; Brandenburg, H.; Conrow, T.; Evans, T.; Fowler, J.; Jarrett, T.; Marsh, K.; Masci, F.; McCallon, H.; Wheelock, S.; Wittman, M.; Wyatt, P.; DeBaun, E.; Elliott, G.; Elsbury, D.; Gautier, T., IV; Gomillion, S.; Leisawitz, D.; Maleszewski, C.; Micheli, M.; Wilkins, A. 2011-04-01 The Wide-field Infrared Survey Explorer (WISE) has surveyed the entire sky at four infrared wavelengths with greatly improved sensitivity and spatial resolution compared to its predecessors, the Infrared Astronomical Satellite and the Cosmic Background Explorer. NASA's Planetary Science Division has funded an enhancement to the WISE data processing system called "NEOWISE" that allows detection and archiving of moving objects found in the WISE data. NEOWISE has mined the WISE images for a wide array of small bodies in our solar system, including near-Earth objects (NEOs), Main Belt asteroids, comets, Trojans, and Centaurs. By the end of survey operations in 2011 February, NEOWISE identified over 157,000 asteroids, including more than 500 NEOs and ~120 comets. The NEOWISE data set will enable a panoply of new scientific investigations. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20130010679&hterms=dart+paper&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Ddart%2Bpaper','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20130010679&hterms=dart+paper&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Ddart%2Bpaper">Modeling and Simulation for Multi-Missions Space Exploration Vehicle</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Chang, Max 2011-01-01 Asteroids and Near-Earth Objects [NEOs] are of great interest for future space missions. The Multi-Mission Space Exploration Vehicle [MMSEV] is being considered for future Near Earth Object missions and requires detailed planning and study of its Guidance, Navigation, and Control [GNC]. A possible mission of the MMSEV to a NEO would be to navigate the spacecraft to a stationary orbit with respect to the rotating asteroid and proceed to anchor into the surface of the asteroid with robotic arms. The Dynamics and Real-Time Simulation [DARTS] laboratory develops reusable models and simulations for the design and analysis of missions. In this paper, the development of guidance and anchoring models are presented together with their role in achieving mission objectives and relationships to other parts of the simulation. One important aspect of guidance is in developing methods to represent the evolution of kinematic frames related to the tasks to be achieved by the spacecraft and its robot arms. In this paper, we compare various types of mathematical interpolation methods for position and quaternion frames. Subsequent work will be on analyzing the spacecraft guidance system with different movements of the arms. With the analyzed data, the guidance system can be adjusted to minimize the errors in performing precision maneuvers. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013sf2a.conf..183H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013sf2a.conf..183H">PôDET: A Centre for Earth Dynamical Environment</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Hestroffer, D.; Deleflie, F. 2013-11-01 The monitoring of the Earth space environment has gained some importance these last decades, in particular at the European level, partly because the phenomenon which origin come from space can have socio-economic consequences; and also because our understanding of those phenomenon - their associated prediction and risks - is still limited. For instance, the Space Situational Awareness programme (SSA) at ESA has set up in 2013 a centre and network for aspects connected to space debris (SST), to space weather (SW), and to near-Earth objects (NEO). At IMCCE, the Pôle sur la dynamique de l'environnement terrestre} (PODET, \\url{podet.imcce.fr}) for the Earth dynamical environment is studying effects and prediction for natural and artificial objects gravitating in the Earth vicinity. These studies englobe near-Earth objects, asteroids, comets, meteoroids, meteorite streams, and space debris. For all object types that are concerned, a general scheme of a functional analysis has been developed. It encompasses data acquisition with dedicated observations--essentially astrometric--or database queries, orbit determination or adjustment, prediction and ephemerides, and eventually impact probability computation and data dissemination. We develop here the general context of this action, the PôDET project, its scientific objectives, interaction with other disciplines, and the development in progress for dedicated tools. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMPA42B..05B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMPA42B..05B">Asteroid Airbursts: Risk Assessment and Reduction</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Boslough, M. 2015-12-01 Airbursts are events in which small (meters to tens-of-meters in diameter) asteroids deposit most of their energy in the atmosphere with a total energy greater than small nuclear explosions (>0.1 kilotons of TNT). The airburst risk is higher than previous assessments for two reasons. First, they are more frequent than previously thought. The Tunguska-class (~40 meters) population estimate has doubled, and Chelyabinsk-class (~20 meters) has increased by a factor of 2.6. Second, asteroid airbursts are significantly more damaging than previously assumed. In most cases, they more efficiently couple energy to the surface than nuclear explosions of the same yield. Past Near-Earth Object (NEO) risk assessments concluded that the largest asteroids (> 1 km) dominated the hazard. Large NEOs represent only a tiny fraction of the population but the potential for global catastrophe means that the contribution from low-probability, high-consequence events is large. Nearly 90% of these objects, none of which is on a collision course, have been catalogued. This has reduced their assessed near-term statistical risk by more than an order of magnitude because completion is highest for the largest and most dangerous. The relative risk from small objects would therefore be increasing even if their absolute assessed risk were not. Uncertainty in the number of small NEOs remains large and can only be reduced by expanded surveys. One strategy would be to count small NEOs making close passes in statistically significant numbers. For example, there are about 25 times as many objects of a given size that pass within the distance of geosynchronous orbit than collide with the earth, and 2000 times as many pass within a lunar distance (accounting for gravitational focusing). An asteroid the size of the Chelyabinsk impactor (~20 m) could potentially be observed within geosynchronous orbit every two years and within lunar orbit nearly once a week. A Tunguska-sized asteroid (~40 m) passes within a lunar distance several times a year. A survey optimized to discover and count these objects would rapidly reduce the uncertainty in their populations. An additional benefit would be early warning of an imminent impact to give authorities time to issue evacuation or take-cover instructions in circumstances for which there would be no time the prevent an impact. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26215051','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26215051">Asteroid Risk Assessment: A Probabilistic Approach.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Reinhardt, Jason C; Chen, Xi; Liu, Wenhao; Manchev, Petar; Paté-Cornell, M Elisabeth 2016-02-01 Following the 2013 Chelyabinsk event, the risks posed by asteroids attracted renewed interest, from both the scientific and policy-making communities. It reminded the world that impacts from near-Earth objects (NEOs), while rare, have the potential to cause great damage to cities and populations. Point estimates of the risk (such as mean numbers of casualties) have been proposed, but because of the low-probability, high-consequence nature of asteroid impacts, these averages provide limited actionable information. While more work is needed to further refine its input distributions (e.g., NEO diameters), the probabilistic model presented in this article allows a more complete evaluation of the risk of NEO impacts because the results are distributions that cover the range of potential casualties. This model is based on a modularized simulation that uses probabilistic inputs to estimate probabilistic risk metrics, including those of rare asteroid impacts. Illustrative results of this analysis are presented for a period of 100 years. As part of this demonstration, we assess the effectiveness of civil defense measures in mitigating the risk of human casualties. We find that they are likely to be beneficial but not a panacea. We also compute the probability-but not the consequences-of an impact with global effects ("cataclysm"). We conclude that there is a continued need for NEO observation, and for analyses of the feasibility and risk-reduction effectiveness of space missions designed to deflect or destroy asteroids that threaten the Earth. © 2015 Society for Risk Analysis. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.3051L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.3051L">Identifying Potentially Hazardous Co-orbiting Material of Known NEOs Using Magnetic Signatures Produced in Destructive Collisions</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Lai, Hairong; Russell, Christopher; Jia, Yingdong; Wei, Hanying; Connors, Martin 2015-04-01 It is estimated that over 99% of near-Earth objects (NEOs) with diameters of about tens of meters are undiscovered. However, simulations show that they result in the most damage per year. Many of these bodies, produced in non-destructive collisions with larger well-characterized NEOs, are co-orbiting with their parent objects. Thereafter, scattering will occur due to gravitational perturbations when the co-orbiters have close encounters to any planets. Such gravitational scattering may not affect the orbits of the parent body. Therefore "safe" NEOs which have negligible impact probability with the Earth may be accompanied by potentially hazardous co-orbiting material. Those co-orbitals do reveal their existence in collisions with meteoroids, which are numerous and can be as small as tens of centimeters in diameter. Clouds of fine dust/gas particles released in such collisions become charged after generation and interact coherently with the solar wind electromagnetically. The interplanetary magnetic field is then perturbed. The resultant structures have been called interplanetary field enhancements (IFEs). They are readily identified when they pass spacecraft equipped with magnetometers. Although the co-orbitals responsible for the IFEs were disrupted in collisions, they are valid samples of the remaining co-orbiting material. Therefore, we can use IFEs to identify the spatial and mass distribution of such co-orbitals. With statistical studies of IFE occurrence, we identified asteroid 2201 Oljato and asteroid 138175 to have such co-orbiting material. The mass of the co-orbitals can be inferred by combining the results from observations and MHD simulations. Multi-spacecraft simultaneous observations measure the dimensions of the magnetic perturbations and the forces lifting them away from the Sun, while multi-fluid simulations give the accelerations of the perturbations. In summary, our technique not only helps us to identify which NEOs are accompanied by hazardous co-orbitals, but also gives their mass distributions. Although our technique provides only the statistical properties, it indicates where high resolution optical surveys should be obtained in order to identify and track specific hazardous bodies. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015hsa8.conf..828R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015hsa8.conf..828R">Towards an autonomous telescope system: the Test-Bed Telescope project</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Racero, E.; Ocaña, F.; Ponz, D.; the TBT Consortium 2015-05-01 In the context of the Space Situational Awareness (SSA) programme of ESA, it is foreseen to deploy several large robotic telescopes in remote locations to provide surveillance and tracking services for man-made as well as natural near-Earth objects (NEOs). The present project, termed Telescope Test Bed (TBT) is being developed under ESA's General Studies and Technology Programme, and shall implement a test-bed for the validation of an autonomous optical observing system in a realistic scenario, consisting of two telescopes located in Spain and Australia, to collect representative test data for precursor NEO services. It is foreseen that this test-bed environment will be used to validate future prototype software systems as well as to evaluate remote monitoring and control techniques. The test-bed system will be capable to deliver astrometric and photometric data of the observed objects in near real-time. This contribution describes the current status of the project. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/22348173-discovery-cometary-activity-near-earth-asteroid-don-quixote','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22348173-discovery-cometary-activity-near-earth-asteroid-don-quixote">The discovery of cometary activity in near-Earth asteroid (3552) Don Quixote</a> <a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Mommert, Michael; Harris, Alan W.; Hora, Joseph L. The near-Earth object (NEO) population, which mainly consists of fragments from collisions between asteroids in the main asteroid belt, is thought to include contributions from short-period comets as well. One of the most promising NEO candidates for a cometary origin is near-Earth asteroid (3552) Don Quixote, which has never been reported to show activity. Here we present the discovery of cometary activity in Don Quixote based on thermal-infrared observations made with the Spitzer Space Telescope in its 3.6 and 4.5 μm bands. Our observations clearly show the presence of a coma and a tail in the 4.5 μm but notmore » in the 3.6 μm band, which is consistent with molecular band emission from CO{sub 2}. Thermal modeling of the combined photometric data on Don Quixote reveals a diameter of 18.4{sub −0.4}{sup +0.3} km and an albedo of 0.03{sub −0.01}{sup +0.02}, which confirms Don Quixote to be the third-largest known NEO. We derive an upper limit on the dust production rate of 1.9 kg s{sup –1} and derive a CO{sub 2} gas production rate of (1.1 ± 0.1) × 10{sup 26} molecules s{sup –1}. Spitzer Infrared Spectrograph spectroscopic observations indicate the presence of fine-grained silicates, perhaps pyroxene rich, on the surface of Don Quixote. Our discovery suggests that CO{sub 2} can be present in near-Earth space over a long time. The presence of CO{sub 2} might also explain that Don Quixote's cometary nature remained hidden for nearly three decades.« less </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AAS...21943215T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AAS...21943215T">Physical Characterization of Near-Earth Object 3988 (1986 LA)</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Truong, Thien-Tin; Hicks, M.; Strojia, C.; Teague, S.; Gerhart, C.; McCormack, M. 2012-01-01 The Near-Earth Object (NEO) 3988 (1986 LA) was discovered photographically by Glo Helin and colleagues with the 1.2-m Schmidt at Palomar (Helin et al. 1986: IAU Circ. 4228). With a perihelion distance q = 1.055 AU, 1986 LA is an Amor-type NEO. The spacecraft rendezvous potential of any small solar system body can be quantified, to first order, by the dV required to match the target's orbit. Using the method described by Shoemaker & Helin (1978; N7829022) and assuming a massless rendezvous target, a dV of 6.29 km/s is required to reach the orbit of Mars. Objects with dV < 6.29 km/s can therefor be considered low-dV targets: 1791 NEOs meet this criteria. 1986 LA has a dV of 5.84 km/s. With an absolute magnitude H = 17.7 (Lowell Astorb Database), the object is in the top 0.985 percentile in terms of expected size. We obtained four nights of Bessel BVRI on 2011 June 14, 15, 16, and 18 at the JPL Table Mountain 0.6-m telescope. Our analysis was hampered by the high density of background stars, the low lunar elongation, and an intermittent tracking error. The rotationally averaged colors were found most consistent with an Ld-type spectral classification (Bus taxonomy), an association obtained through a comparison of our colors with the 1341 asteroid spectra in the SMASS II database (Bus & Binzel 2002). Despite the large error bars in our photometry we are confident that 1986 LA belongs to the S-family of asteroids (Tholen Taxonomy). Assuming a phase parameter G=0.15 and our V-R color, we measured an absolute magnitude HV = 17.97 +/- 0.15 mag, intermediate between the HV = 17.7 mag (Lowell) and HV = 18.2 mag (JPL) database listings. We observed for 21 additional nights. The pole positions are currently unresolved based on the further observations. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070019778','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070019778">Near Earth Object (NEO) Mitigation Options Using Exploration Technologies</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Arnold William; Baysinger, Mike; Crane, Tracie; Capizzo, Pete; Sutherlin, Steven; Dankanich, John; Woodcock, Gordon; Edlin, George; Rushing, Johnny; Fabisinski, Leo; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20070019778'); toggleEditAbsImage('author_20070019778_show'); toggleEditAbsImage('author_20070019778_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20070019778_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20070019778_hide"> 2007-01-01 This work documents the advancements in MSFC threat modeling and mitigation technology research completed since our last major publication in this field. Most of the work enclosed here are refinements of our work documented in NASA TP-2004-213089. Very long development times from start of funding (10-20 years) can be expected for any mitigation system which suggests that delaying consideration of mitigation technologies could leave the Earth in an unprotected state for a significant period of time. Fortunately there is the potential for strong synergy between architecture requirements for some threat mitigators and crewed deep space exploration. Thus planetary defense has the potential to be integrated into the current U.S. space exploration effort. The number of possible options available for protection against the NEO threat was too numerous for them to all be addressed within the study; instead, a representative selection were modeled and evaluated. A summary of the major lessons learned during this study is presented, as are recommendations for future work. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EPSC....8..936E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EPSC....8..936E">Are we producing PHAs? On the target selection for a proposed mitigation demo-mission within the NEO-Shield project</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Eggl, S.; Hestroffer, D.; Thuillot, W. 2013-09-01 The Chelyabinsk event on February 15th, 2013 has shown once again that even small near earth objects (NEOs) can become a real safety concern. Eventhough we believe to have the capabilities to avert larger potentially disastrous asteroid impacts, only the realization of mitigation demonstration missions can confirm this claim. The target selection process for such deflection demonstrations is a demanding task, as physical, dynamical and engineering aspects have to be considered in great detail. One of the top priorities of such a demonstration mission is, of course, that a harmless asteroid should not be turned into a potentially hazardous object (PHO). Given the potentially large uncertainties in the asteroid's physical parameters as well as the additional uncertainties introduced during the deflection attempt, an in depth analysis of the impact probabilities over the next century becomes necessary, in order to exclude an augmentation of potential risks. Assuming worst case scenarios regard- ing the orbital, physical and mitigation induced uncertainties, we provide a keyhole and impact risk analysis of a list of potential targets for the mitigation demomission proposed in the framework of the NEO-Shield project. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMNH53B3895B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMNH53B3895B">Post-Chelyabinsk Risk Assessment for Near Earth Objects (NEOs)</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Boslough, M.; Harris, A. W. 2014-12-01 The widely-accepted NEO risk assessments published in the 1990s concluded that the largest asteroids (> 1 km) dominated the hazard. Even though large NEOs represent only a tiny fraction of the population because of a power-law size distribution, the potential for global catastrophe means that the contribution from these low-probability, high-consequence events is large. This conclusion led to the Spaceguard survey, which has now catalogued about 90% of these objects, none of which is on a collision course. The survey has reduced the assessed risk from this size range by more than an order of magnitude because completion is highest for the largest and most dangerous. The relative risk from objects tens of meters in diameter is therefore increasing.The absolute assessed risk from airbursts caused by objects of this size is also higher for two reasons. First, they may be more frequent than previously thought because of an underestimated population. Second, they are significantly more damaging than assumed in the original assessment because (in most cases) they more efficiently couple energy to the surface than nuclear explosions. Last year's half-megaton airburst over Chelyabinsk, Russia, appears to challenge the notion that such events are extremely rare—especially when also considering the 1908 Tunguska event along with decades of infrasound bolide data showing higher-than-expected numbers of large airbursts.We will present a new analysis of the risk based on updated estimates for the population of undiscovered NEOs, taking into account the enhanced damage potential of collisional airbursts. Merging the survey population estimates with the bolide frequency estimates suggests a population of tens-of-meters sized bodies that may be a factor of three or so greater than estimated from surveys alone. Uncertainty in the population of airburst-class NEOs remains quite large, and can only be unambiguously reduced by expanded surveys focused on objects in the tens-of-meters size range. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94AL85000. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active">11</li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active">12</li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015A%26A...584A..97T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015A%26A...584A..97T">2P/Encke, the Taurid complex NEOs and the Maribo and Sutter's Mill meteorites</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Tubiana, C.; Snodgrass, C.; Michelsen, R.; Haack, H.; Böhnhardt, H.; Fitzsimmons, A.; Williams, I. P. 2015-12-01 Aims: 2P/Encke is a short period comet that was discovered in 1786 and has been extensively observed and studied for more than 200 years. The Taurid meteoroid stream has long been linked with 2P/Encke owing to a good match of their orbital elements, even though the comet's activity is not strong enough to explain the number of observed meteors. Various small near-Earth objects (NEOs) have been discovered with orbits that can be linked to 2P/Encke and the Taurid meteoroid stream. Maribo and Sutter's Mill are CM type carbonaceous chondrite that fell in Denmark on January 17, 2009 and April 22, 2012, respectively. Their pre-atmospheric orbits place them in the middle of the Taurid meteoroid stream, which raises the intriguing possibility that comet 2P/Encke could be the parent body of CM chondrites. Methods: To investigate whether a relationship between comet 2P/Encke, the Taurid complex associated NEOs, and CM chondrites exists, we performed photometric and spectroscopic studies of these objects in the visible wavelength range. We observed 2P/Encke and 10 NEOs on August 2, 2011 with the FORS instrument at the 8.2 m Very Large Telescope on Cerro Paranal (Chile). Results: Images in the R filter, used to investigate the possible presence of cometary activity around the nucleus of 2P/Encke and the NEOs, show that no resolved coma is present. None of the FORS spectra show the 700 nm absorption feature due to hydrated minerals that is seen in the CM chondrite meteorites. All objects show featureless spectra with moderate reddening slopes at λ< 800 nm. Apart for 2003 QC10 and 1999 VT25, which show a flatter spectrum, the spectral slope of the observed NEOs is compatible with that of 2P/Encke. However, most of the NEOs show evidence of a silicate absorption in lower S/N data at λ> 800 nm, which is not seen in 2P/Encke, which suggests that they are not related. Conclusions: Despite similar orbits, we find no spectroscopic evidence for a link between 2P/Encke, the Taurid complex NEOs and the Maribo and Sutter's Mill meteorites. However, we cannot rule out a connection to the meteorites either, as the spectral differences may be caused by secondary alteration of the surfaces of the NEOs. Based on observations performed at the European Southern Observatory, Paranal, Chile: Program 087.C-0788(A). </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040084672','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040084672">AsterAnts: A Concept for Large-Scale Meteoroid Return and Processing using the International Space Station</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Globus, Al; Biegel, Bryan A.; Traugott, Steve 2004-01-01 AsterAnts is a concept calling for a fleet of solar sail powered spacecraft to retrieve large numbers of small (1/2-1 meter diameter) Near Earth Objects (NEOs) for orbital processing. AsterAnts could use the International Space Station (ISS) for NEO processing, solar sail construction, and to test NEO capture hardware. Solar sails constructed on orbit are expected to have substantially better performance than their ground built counterparts [Wright 1992]. Furthermore, solar sails may be used to hold geosynchronous communication satellites out-of-plane [Forward 1981] increasing the total number of slots by at least a factor of three. potentially generating $2 billion worth of orbital real estate over North America alone. NEOs are believed to contain large quantities of water, carbon, other life-support materials and metals. Thus. with proper processing, NEO materials could in principle be used to resupply the ISS, produce rocket propellant, manufacture tools, and build additional ISS working space. Unlike proposals requiring massive facilities, such as lunar bases, before returning any extraterrestrial larger than a typical inter-planetary mission. Furthermore, AsterAnts could be scaled up to deliver large amounts of material by building many copies of the same spacecraft, thereby achieving manufacturing economies of scale. Because AsterAnts would capture NEOs whole, NEO composition details, which are generally poorly characterized, are relatively unimportant and no complex extraction equipment is necessary. In combination with a materials processing facility at the ISS, AsterAnts might inaugurate an era of large-scale orbital construction using extraterrestrial materials. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040074232&hterms=puzzle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dpuzzle','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040074232&hterms=puzzle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dpuzzle">Physical Characterization of the Near-Earth Object Population</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Binzel, Richard P. 2004-01-01 Many pieces of the puzzle must be brought together in order to have a clear picture of the near-Earth object (NEO) population. Four of the pieces that can be described include: i) the taxonomic distribution of the population as measured by observational sampling, ii) the determination of albedos that can be associated with the taxonomic distribution, iii) discovery statistics for the NE0 population, and iv) the debiasing of the discovery statistics using the taxonomic and albedo information. Support from this grant enables us to address three of these four pieces. Binzel et al. (2004, submitted) presents the first piece, detailing the observations and observed characteristics of the NE0 and Mars-crossing (MC) population. For the second piece, a complementary program of albedo measurements is pursued at the Keck Observatory (Binzel, P. I.) with first results published in Delbo et al. (2003). For the third piece, the most extensive NE0 discovery statistics are provided by the LINEAR survey. Binzel has supervised the MIT Ph. D. thesis work of Stuart (2003) to bring the fourth piece, submitted for publication by Stuart and Binzel (2004). Our results provide new constraints for the NE0 population and progress for the Spaceguard Survey, illuminate asteroid and comet source regions for the NEOs, and provide new evidence for space weathering processes linking asteroids and meteorites. Further, we are identifying top priority near-Earth spacecraft mission candidates based on their spectral properties and inferred compositions. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.P43A1427S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.P43A1427S">Low Cost Multiple Near Earth Object Missions</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Smith, D. B.; Klaus, K.; Kaplan, M. 2009-12-01 Commercial spacecraft are available with efficient high power solar arrays and hybrid propulsion systems (Chemical and Solar Electric) that make possible multiple Near Earth Object Missions within Discovery budget limits. Our analysis is based on the Geosynchronous Transfer Orbit Capability (GTOC-3) solution. GTOC-3 assumptions: - Escape from Earth, rendezvous with 3 asteroids, then rendezvous with Earth - Departure velocity below 0.5 km/s - Launch between 2016 and 2025 - Total trip time less than 10 years - Minimum stay time of 60 days at each asteroid - Initial spacecraft mass of 2,000 kg - Thrust of 0.15 N and Isp of 3,000 s - Only Earth GAMs allowed (Rmin = 6,871 km) Preliminary results indicate that for mission objectives we can visit Apophis and any other 2 asteroids on this list or any other 3 asteroids listed. We have considered two spacecraft approaches to accomplish mission objectives: - Case 1: Chemical engine burn to the 1st target, and then solar electric to the 2nd and 3rd targets, or - Case 2: Solar electric propulsion to all 3 targets For both Cases, we assumed an instrument mass of up to 100 kg, power up to 100 W, and s/c bus pointing as good as 12 arc sec.Multi-NEO Mission Candidates </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMIN14A..02J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMIN14A..02J">A Knowledge Discovery framework for Planetary Defense</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Jiang, Y.; Yang, C. P.; Li, Y.; Yu, M.; Bambacus, M.; Seery, B.; Barbee, B. 2016-12-01 Planetary Defense, a project funded by NASA Goddard and the NSF, is a multi-faceted effort focused on the mitigation of Near Earth Object (NEO) threats to our planet. Currently, there exists a dispersion of information concerning NEO's amongst different organizations and scientists, leading to a lack of a coherent system of information to be used for efficient NEO mitigation. In this paper, a planetary defense knowledge discovery engine is proposed to better assist the development and integration of a NEO responding system. Specifically, we have implemented an organized information framework by two means: 1) the development of a semantic knowledge base, which provides a structure for relevant information. It has been developed by the implementation of web crawling and natural language processing techniques, which allows us to collect and store the most relevant structured information on a regular basis. 2) the development of a knowledge discovery engine, which allows for the efficient retrieval of information from our knowledge base. The knowledge discovery engine has been built on the top of Elasticsearch, an open source full-text search engine, as well as cutting-edge machine learning ranking and recommendation algorithms. This proposed framework is expected to advance the knowledge discovery and innovation in planetary science domain. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160014560','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160014560">Planetary Defense Architecture for Mitigating Short-Term Warning Cosmic Threats: READI Project</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Nambiar, Shrrirup; Hussein, Alaa; Silva-Martinez, Jackelynne; Reinert, Jessica; Gonzalez, Fernando 2016-01-01 Earth is being constantly bombarded by a large variety of celestial bodies and has been since its formation 4.5 billion years ago. Among those bodies, mainly asteroids and comets, there are those that have the potential to create large scale destruction upon impact. The only extinction-level impact recorded to date was 65 million years ago, during the era of dinosaurs. The probability of another extinction-level, or even city-killer, impact may be negligible, but the consequences can be severe for the biosphere and for our species. Therefore it is highly imperative for us to be prepared for such a devastating impact in the near future, especially since humanity is at the threshold of wielding technologies that allow us to do so. Majority of scientists, engineers, and policymakers have focused on long-term strategies and warning periods for Earth orbit crossing Near-Earth Objects (NEOs), and have suggested methods and policies to tackle such problems. However, less attention has been paid to short warning period NEO threats. Such NEOs test current technological and international cooperation capabilities in protecting ourselves, and can create unpredictable devastation ranging from local to global scale. The most recent example is the Chelyabinsk incident in Russia. This event has provided a wakeup call for space agencies and governments around the world towards establishing a Planetary Defense Program. The Roadmap for EArth Defense Initiative (READI) is a project by a team of international, intercultural, and interdisciplinary participants of the International Space University's Space Studies Program 2015 hosted by Ohio University, Athens, OH proposing a roadmap for space agencies, governments, and the general public to tackle NEOs with a short warning before impact. Taking READI as a baseline, this paper presents a technical description of methodologies proposed for detection and impact mitigation of a medium-sized comet (up to 800m across) with a short-warning period of two years on a collision course with Earth. The hypothetical comet is on a highly-inclined orbit having a high probability for Earth impact after its perihelion. For detection, we propose a space-based infrared detection system consisting of two satellites located at the Earth-Moon Lagrange points L1 and L2 coupled with space observatories, like the James Webb telescope and the Centennial telescope. These telescopes are supported by ground-based telescopes, like the Arecibo and Green Bank telescope, in the search for NEOs. Upon detection, the comet is tracked constantly using space- and ground-based telescopes. The deflection system is two-pronged, firstly involving the use of a high energy Directed Energy Laser Terminals (DELT) placed at Sun-Earth Lagrange points L4 and L5 so as to initiate and increase the ablation rate of the comet and deviate it from its collision trajectory, and secondly by the Hypervelocity Comet Intercept Vehicle (HCIV), a space-borne system combining a kinetic impactor with a thermonuclear device. The policy and international collaboration aspects to implement these methods are also outlined in the paper. The techniques mentioned could also be applied to mitigate medium-to-large sized asteroids (up to 2km across). </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160010365','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160010365">Architecture for Mitigating Short-Term Warning Cosmic Threats: READI Project</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Nambiar, Shrrirup P.; Hussein, Alaa; Silva-Martinez, Jackelynne; Reinert, Jessica; Gonzalez, Fernando 2016-01-01 Earth is being constantly bombarded by a large variety of celestial bodies and has been since its formation 4.5 billion years ago. Among those bodies, mainly asteroids and comets, there are those that have the potential to create large scale destruction upon impact. The only extinction-level impact recorded to date was 65 million years ago, during the era of dinosaurs. The probability of another extinction-level, or even city-killer, impact may be negligible, but the consequences can be severe for the biosphere and for our species. Therefore it is highly imperative for us to be prepared for such a devastating impact in the near future, especially since humanity is at the threshold of wielding technologies that allow us to do so. Majority of scientists, engineers, and policymakers have focused on long-term strategies and warning periods for Earth orbit crossing Near-Earth Objects (NEOs), and have suggested methods and policies to tackle such problems. However, less attention has been paid to short warning period NEO threats. Such NEOs test current technological and international cooperation capabilities in protecting ourselves, and can create unpredictable devastation ranging from local to global scale. The most recent example is the Chelyabinsk incident in Russia. This event has provided a wakeup call for space agencies and governments around the world towards establishing a Planetary Defense Program. The Roadmap for EArth Defense Initiative (READI) is a project by a team of international, intercultural, and interdisciplinary participants of the International Space University's Space Studies Program 2015 hosted by Ohio University, Athens, OH proposing a roadmap for space agencies, governments, and the general public to tackle NEOs with a short warning before impact. Taking READI as a baseline, this paper presents a technical description of methodologies proposed for detection and impact mitigation of a medium-sized comet (up to 800m across) with a short-warning period of two years on a collision course with Earth. The hypothetical comet is on a highly-inclined orbit having a high probability for Earth impact after its perihelion. For detection, we propose a space-based infrared detection system consisting of two satellites located at the Earth-Moon Lagrange points L1 and L2 coupled with space observatories, like the James Webb telescope and the Centennial telescope. These telescopes are supported by ground-based telescopes, like the Arecibo and Green Bank telescope, in the search for NEOs. Upon detection, the comet is tracked constantly using space- and ground-based telescopes. The deflection system is two-pronged, firstly involving the use of a high energy Directed Energy Laser Terminals (DELT) placed at Sun-Earth Lagrange points L4 and L5 so as to initiate and increase the ablation rate of the comet and deviate it from its collision trajectory, and secondly by the Hypervelocity Comet Intercept Vehicle (HCIV), a space-borne system combining a kinetic impactor with a thermonuclear device. The policy and international collaboration aspects to implement these methods are also outlined in the paper. The techniques mentioned could also be applied to mitigate medium-to-large sized asteroids (up to 2km across). </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DPS....4730815N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DPS....4730815N">Astrometric Results of NEOs from the Characterization and Astrometric Follow-up Program at Adler Planetarium</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Nault, Kristie A.; Brucker, Melissa J.; Hammergren, Mark; Gyuk, Geza; Solontoi, Mike R. 2015-11-01 We present astrometric results of near-Earth objects (NEOs) targeted in fourth quarter 2014 and in 2015. This is part of Adler Planetarium’s NEO characterization and astrometric follow-up program, which uses the Astrophysical Research Consortium (ARC) 3.5-m telescope at Apache Point Observatory (APO). The program utilizes a 17% share of telescope time, amounting to a total of 500 hours per year. This time is divided up into two hour observing runs approximately every other night for astrometry and frequent half-night runs approximately several times a month for spectroscopy (see poster by M. Hammergren et. al.) and light curve studies (see poster by M. J. Brucker et. al.).Observations were made using Seaver Prototype Imaging Camera (SPIcam), a visible-wavelength, direct imaging CCD camera with 2048 x 2048 pixels and a field of view of 4.78’ x 4.78’. Observations were made using 2 x 2 binning.Special emphasis has been made to focus on the smallest NEOs, particularly around 140m in diameter. Targets were selected based on absolute magnitude (prioritizing for those with H > 25 mag to select small objects) and a 3σ uncertainty less than 400” to ensure that the target is in the FOV. Targets were drawn from the Minor Planet Center (MPC) NEA Observing Planning Aid, the JPL What’s Observable tool, and the Spaceguard priority list and faint NEO list.As of August 2015, we have detected 670 NEOs for astrometric follow-up, on point with our goal of providing astrometry on a thousand NEOs per year. Astrometric calculations were done using the interactive software tool Astrometrica, which is used for data reduction focusing on the minor bodies of the solar system. The program includes automatic reference star identification from new-generation star catalogs, access to the complete MPC database of orbital elements, and automatic moving object detection and identification.This work is based on observations done using the 3.5-m telescope at Apache Point Observatory, owned and operated by the Astrophysical Research Consortium. We acknowledge the support from the NASA NEOO award NNX14AL17G and thank the University of Chicago Astronomy and Astrophysics Department for observing time in 2014. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DPS....4740207B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DPS....4740207B">Orbital and Physical Characteristics of Meter-sized Earth Impactors</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Brown, Peter G.; Wiegert, Paul; Clark, David; Tagliaferri, Edward 2015-11-01 We have analysed the orbits and ablation characteristics in the atmosphere of more than 60 earth-impacting meteoroids of one meter in diameter or larger. Using heights at peak luminosity as a proxy for strength, we find that there is roughly an order of magnitude spread in the apparent strength of the population of meter-sized impactors at the Earth. The orbits and physical strength of these objects are consistent with the majority being asteroidal bodies originating from the inner main asteroid belt. We find ~10-15% of our objects have a probable cometary (Jupiter-Family comet and/or Halley-type comet) origin based on orbital characteristics alone. Only half this number, however, show evidence for the expected weaker than average structure compared to asteroidal bodies. Almost all impactors show peak brightness between 20-40 km altitude. Several events have exceptionally high (relative to the remainder of the population) heights of peak brightness. These are physically most consistent with high microporosity objects, though all were on asteroidal-type orbits. We also find three events, including the Oct 8, 2009 airburst near Sulawesi, Indonesia, which display comparatively low heights of peak brightness, consistent with strong monolithic stones or iron meteoroids. Based on orbital similarity, we find a probable connection among several NEOs in our population with the Taurid meteoroid complex. No other major meteoroid streams show linkages with the pre-atmospheric orbits of our meter-class impactors. Our events cover almost four orders of magnitude in mass, but no trend in height of peak brightness is evident, suggesting no strong trend in strength with size for small NEOs, a finding consistent with the results of Popova et al (2011). </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AJ....155..163Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AJ....155..163Y">Finding Long Lost Lexell's Comet: The Fate of the First Discovered Near-Earth Object</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Ye, Quan-Zhi; Wiegert, Paul A.; Hui, Man-To 2018-04-01 Jupiter-family Comet D/1770 L1 (Lexell) was the first discovered Near-Earth Object (NEO) and passed the Earth on 1770 July 1 at a recorded distance of 0.015 au. The comet was subsequently lost due to unfavorable observing circumstances during its next apparition followed by a close encounter with Jupiter in 1779. Since then, the fate of D/Lexell has attracted interest from the scientific community, and now we revisit this long-standing question. We investigate the dynamical evolution of D/Lexell based on a set of orbits recalculated using the observations made by Charles Messier, the comet’s discoverer, and find that there is a 98% chance that D/Lexell remains in the solar system by the year of 2000. This finding remains valid even if a moderate non-gravitational effect is imposed. Messier’s observations also suggest that the comet is one of the largest known near-Earth comets, with a nucleus of ≳10 km in diameter. This implies that the comet should have been detected by contemporary NEO surveys regardless of its activity level if it has remained in the inner solar system. We identify asteroid 2010 JL33 as a possible descendant of D/Lexell, with a 0.8% probability of chance alignment, but a direct orbital linkage of the two bodies has not been successfully accomplished. We also use the recalculated orbit to investigate the meteors potentially originating from D/Lexell. While no associated meteors have been unambiguously detected, we show that meteor observations can be used to better constrain the orbit of D/Lexell despite the comet being long lost. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007IAUS..236...55I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007IAUS..236...55I">Migration of comets to the terrestrial planets</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Ipatov, Sergei I.; Mather, John C. 2007-05-01 The orbital evolution of 30,000 objects with initial orbits close to those of Jupiter-family comets (JFCs) and also of 15,000 dust particles was integrated [1-3]. For initial orbital elements close to those of Comets 2P, 10P, 44P, and 113P, a few objects got Earth-crossing orbits with semi-major axes a<2 AU and aphelion distances Q<4.2 AU, or even got inner-Earth (Q<0.983 AU), Aten, or typical asteroidal orbits, and moved in such orbits for more than 1 Myr (up to tens or even hundreds of Myrs). Most of former trans-Neptunian objects that have typical near-Earth object (NEO) orbits moved in such orbits for Myrs, so during most of this time they were extinct comets. From a dynamical point of view, the fraction of extinct comets among NEOs can exceed several tens of percent, but, probably, many extinct comets disintegrated into mini-comets and dust during a smaller part of their dynamical lifetimes if these lifetimes were large. The probability of the collision of Comet 10P with the Earth during a dynamical lifetime of the comet was P[E]≈1.4•10-4, but 80% of this mean probability was due only to one object among 2600 considered objects with orbits close to that of Comet 10P. For runs for Comet 2P, P[E]≈(1-5)•10-4. For most other considered JFCs, 10-6 < P[E] < 10-5. For Comets 22P and 39P, P[E]≈ (1-2)•10-6; and for Comets 9P, 28P and 44P, P[E]≈(2-5)•10-6. For all considered JFCs, P[E]>4•10-6. The Bulirsh-Stoer method of integration and a symplectic method gave similar results. In our runs the probability of a collision of one object with the Earth could be greater than the sum of probabilities for thousands of other objects. The ratios of probabilities of collisions of JFCs with Venus and Mars to the mass of a planet usually were not smaller than that for Earth. For dust particles started from comets and asteroids, P[E ]was maximum for diameters d~100 μm. These maximum values of P [E] were usually (exclusive for 2P) greater at least by an order of magnitude than the values for parent comets. [1] Ipatov S.I. and Mather J.C. (2004) Annals of the New York Acad. of Sci., v. 1017, 46-65. [2] Ipatov S.I. et al. (2004) Annals of the New York Acad. of Sci., v. 1017, 66-80. [3] Ipatov S.I. and Mather J.C. (2006) Adv. in Space Res., v. 37, N 1, 126-137. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016IAUS..318...91J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016IAUS..318...91J">Active Asteroids in the NEO Population</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Jenniskens, Peter 2016-01-01 Some main-belt asteroids evolve into near-Earth objects. They can then experience the same meteoroid-producing phenomena as active asteroids in the main belt. If so, they would produce meteoroid streams, some of which evolve to intersect Earth's orbit and produce meteor showers at Earth. Only few of those are known. Meteoroid streams that move in orbits with Tisserand parameter well in excess of 3 are the Geminids and Daytime Sextantids of the Phaethon complex and the lesser known epsilon Pegasids. The observed activity appears to be related to nearly whole scale disintegrations, rather than dust ejection from volatile outgassing as observed in active comets. There is only a small population of asteroids with a main-belt origin that recently disintegrated into meteoroid streams. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120000910','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120000910">Solar Electric Propulsion (SEP) Tug Power System Considerations</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Kerslake, Thomas W.; Bury, Kristen M.; Hojinicki, Jeffrey S.; Sajdak, Adam M.; Scheiddegger, Robert J. 2011-01-01 Solar electric propulsion (SEP) technology is truly at the "intersection of commercial and military space" as well as the intersection of NASA robotic and human space missions. Building on the use of SEP for geosynchronous spacecraft station keeping, there are numerous potential commercial and military mission applications for SEP stages operating in Earth orbit. At NASA, there is a resurgence of interest in robotic SEP missions for Earth orbit raising applications, 1-AU class heliocentric missions to near Earth objects (NEOs) and SEP spacecraft technology demonstrations. Beyond these nearer term robotic missions, potential future human space flight missions to NEOs with high-power SEP stages are being considered. To enhance or enable this broad class of commercial, military and NASA missions, advancements in the power level and performance of SEP technologies are needed. This presentation will focus on design considerations for the solar photovoltaic array (PVA) and electric power system (EPS) vital to the design and operation of an SEP stage. The engineering and programmatic pros and cons of various PVA and EPS technologies and architectures will be discussed in the context of operating voltage and power levels. The impacts of PVA and EPS design options on the remaining SEP stage subsystem designs, as well as spacecraft operations, will also be discussed. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016A%26A...594A..52W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016A%26A...594A..52W">Analytical formulation of lunar cratering asymmetries</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Wang, Nan; Zhou, Ji-Lin 2016-10-01 Context. The cratering asymmetry of a bombarded satellite is related to both its orbit and impactors. The inner solar system impactor populations, that is, the main-belt asteroids (MBAs) and the near-Earth objects (NEOs), have dominated during the late heavy bombardment (LHB) and ever since, respectively. Aims: We formulate the lunar cratering distribution and verify the cratering asymmetries generated by the MBAs as well as the NEOs. Methods: Based on a planar model that excludes the terrestrial and lunar gravitations on the impactors and assuming the impactor encounter speed with Earth venc is higher than the lunar orbital speed vM, we rigorously integrated the lunar cratering distribution, and derived its approximation to the first order of vM/venc. Numerical simulations of lunar bombardment by the MBAs during the LHB were performed with an Earth-Moon distance aM = 20-60 Earth radii in five cases. Results: The analytical model directly proves the existence of a leading/trailing asymmetry and the absence of near/far asymmetry. The approximate form of the leading/trailing asymmetry is (1 + A1cosβ), which decreases as the apex distance β increases. The numerical simulations show evidence of a pole/equator asymmetry as well as the leading/trailing asymmetry, and the former is empirically described as (1 + A2cos2ϕ), which decreases as the latitude modulus | ϕ | increases. The amplitudes A1,2 are reliable measurements of asymmetries. Our analysis explicitly indicates the quantitative relations between cratering distribution and bombardment conditions (impactor properties and the lunar orbital status) like A1 ∝ vM/venc, resulting in a method for reproducing the bombardment conditions through measuring the asymmetry. Mutual confirmation between analytical model and numerical simulations is found in terms of the cratering distribution and its variation with aM. Estimates of A1 for crater density distributions generated by the MBAs and the NEOs are 0.101-0.159 and 0.117, respectively. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018RNAAS...2b..57D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018RNAAS...2b..57D">On the Pre-impact Orbital Evolution of 2018 LA, Parent Body of the Bright Fireball Observed Over Botswana on 2018 June 2</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl 2018-06-01 On 2018 June 2, meteoroid 2018 LA became the third natural body ever to be observed before entering our atmosphere ---small asteroids 2014 AA and 2008 TC3 had stricken the Earth on 2014 January 2 and 2008 October 7, respectively. Here, we explore the pre-impact orbital evolution of 2018 LA and investigate the possible presence of known NEOs moving in similar orbits using N-body simulations and the D-criteria. We identify several objects moving in orbits similar to that of 2018 LA and focus on three of them: (454100) 2013 BO73, which is the largest of the group and a PHA, 2016 LR, and 2018 BA5, which follows a path very close to that of 2018 LA in terms of semimajor axis, eccentricity, and inclination. All these objects could be part of a dynamical grouping and their orbital evolution is rather chaotic, experiencing close encounters with Venus, the Earth-Moon system, and Mars. NEO encounters take place at the node and, on the short-term, the relative positions of our planet in its orbit around the Sun repeat every year. Besides the bright fireball observed over Botswana on 2018 June 2, three other bolides were observed early in June in recent years: Crete on 2002 June 6, Washington State on 2004 June 3, and Reisadalen on 2007 June 7. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DDA....4630002H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DDA....4630002H">Increasing Space Situational Awareness for NEOs</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Hestroffer, Daniel J. G. J.; Eggl, Siegfried; Thuillot, William 2015-05-01 Over the past years, Europe has strengthened its commitment to foster space situational awareness. Apart from the current efforts in tracking space weather, artificial satellites and space debris, Near Earth Asteroid threat assessment is a key task. NEOshield has been part of this European effort. We will give an overview over national projects and European programs with French participation such as PoDET, ESTERS, FRIPON, NEOShield, Gaia-FUN-SSO and Stardust. Future plans regarding Near Earth Object threat assessment and mitigation are described. The role of the IMCCE in this framework is discussed using the example of the post mitigation impact risk analyis of Gravity Tractor and Kinetic Impactor based asteroid deflection demonstration mission designs. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20180000050','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20180000050">Electromagnetic Scattering Analysis of Large Size Asteroids/Comets for Reflection/Transmission Tomography (RTT)</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Deshpande, Manohar 2011-01-01 A precise knowledge of the interior structure of asteroids, comets, and Near Earth Objects (NEO) is important to assess the consequences of their impacts with the Earth and develop efficient mitigation strategies. Knowledge of their interior structure also provides opportunities for extraction of raw materials for future space activities. Low frequency radio sounding is often proposed for investigating interior structures of asteroids and NEOs. For designing and optimizing radio sounding instrument it is advantageous to have an accurate and efficient numerical simulation model of radio reflection and transmission through large size bodies of asteroid shapes. In this presentation we will present electromagnetic (EM) scattering analysis of electrically large size asteroids using (1) a weak form formulation and (2) also a more accurate hybrid finite element method/method of moments (FEM/MOM) to help estimate their internal structures. Assuming the internal structure with known electrical properties of a sample asteroid, we first develop its forward EM scattering model. From the knowledge of EM scattering as a function of frequency and look angle we will then present the inverse scattering procedure to extract its interior structure image. Validity of the inverse scattering procedure will be presented through few simulation examples. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994ecli.rept...19P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994ecli.rept...19P">NEO-LISP: Deflecting near-Earth objects using high average power, repetitively pulsed lasers</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Phipps, C. R.; Michaelis, M. M. Several kinds of Near-Earth objects exist for which one would like to cause modest orbit perturbations, but which are inaccessible to normal means of interception because of their number, distance or the lack of early warning. For these objects, LISP (Laser Impulse Space Propulsion) is an appropriate technique for rapidly applying the required mechanical impulse from a ground-based station. In order of increasing laser energy required, examples are: (1) repositioning specially prepared geosynchronous satellites for an enhanced lifetime; (2) causing selected items of space junk to re-enter and burn up in the atmosphere on a computed trajectory; and (3) safely deflecting Earth-directed comet nuclei and earth-crossing asteroids (ECA's) a few tens of meters in size (the most hazardous size). They will discuss each of these problems in turn and show that each application is best matched by its own matrix of LISP laser pulse width, pulse repetition rate, wavelength and average power. The latter ranges from 100W to 3GW for the cases considered. They will also discuss means of achieving the active beam phase error correction during passage through the atmosphere and very large exit pupil in the optical system which are required in each of these cases. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20060020054&hterms=education&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Deducation','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20060020054&hterms=education&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Deducation">NASA Earth Observations (NEO): Data Access for Informal Education and Outreach</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Ward, Kevin; Herring, David 2005-01-01 The NEO (NASA Earth Observations) web space is currently under development with the goal of significantly increasing the demand for NASA remote sensing data while dramatically simplifying public access to georeferenced images. NEO will target the unsophisticated, nontraditional data users who are currently underserved by the existing data ordering systems. These users will include formal and informal educators, museum and science center personnel, professional communicators, and citizen scientists and amateur Earth observers. Users will be able to view and manipulate georeferenced browse imagery and, if they desire, download directly or order the source HDF data from the data provider (e.g., NASA DAAC or science team) via a single, integrated interface. NE0 will accomplish this goal by anticipating users expectations and knowledge level, thus providing an interface that presents material to users in a more simplified manner, without relying upon the jargon/technical terminology that make even the identification of the appropriate data set a significant hurdle. NEO will also act as a gateway that manages users expectations by providing specific details about images and data formats, developing tutorials regarding the manipulation of georeferenced imagery and raw data, links to software tools and ensuring that users are able to get the image they want in the format they want as easily as possible. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.P11B2087R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.P11B2087R">The Main-belt Asteroid and NEO Tour with Imaging and Spectroscopy (MANTIS)</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Rivkin, A.; Cohen, B. A.; Barnouin, O. S.; Chabot, N. L.; Ernst, C. M.; Klima, R. L.; Helbert, J.; Sternovsky, Z. 2015-12-01 The asteroids preserve information from the earliest times in solar system history, with compositions in the population reflecting the material in the solar nebula and experiencing a wide range of temperatures. Today they experience ongoing processes, some of which are shared with larger bodies but some of which are unique to their size regime. They are critical to humanity's future as potential threats, resource sites, and targets for human visitation. However, over twenty years since the first spacecraft encounters with asteroids, they remain poorly understood. The mission we propose here, the Main-belt Asteroid and NEO Tour with Imaging and Spectroscopy (MANTIS), explores the diversity of asteroids to understand our solar system's past history, its present processes, and future opportunities and hazards. MANTIS addresses many of NASA's highest priorities as laid out in its 2014 Science Plan and provides additional benefit to the Planetary Defense and Human Exploration communities via a low-risk, cost-effective tour of the near-Earth and inner asteroid belt. MANTIS visits the materials that witnessed solar system formation and its earliest history, addressing the NASA goal of exploring and observing the objects in the solar system to understand how they formed and evolve. MANTIS measures OH, water, and organic materials via several complementary techniques, visiting and sampling objects known to have hydrated minerals and addressing the NASA goal of improving our understanding of the origin and evolution of life on Earth. MANTIS studies the geology and geophysics of nine diverse asteroids, with compositions ranging from water-rich to metallic, representatives of both binary and non-binary asteroids, and sizes covering over two orders of magnitude, providing unique information about the chemical and physical processes shaping the asteroids, addressing the NASA goal of advancing the understanding of how the chemical and physical processes in our solar system operate, interact, and evolve. Finally, the set of measurements carried out by MANTIS at near-Earth and main-belt asteroids will by definition characterize objects in the solar system that pose threats to Earth or offer resources for human exploration, a final goal in the NASA Science Plan. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active">12</li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active">13</li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014acm..conf..359M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014acm..conf..359M">Spitzer observations of two mission-accessible, tiny asteroids</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Mommert, M.; Hora, J.; Farnocchia, D.; Chesley, S.; Vokrouhlicky, D.; Trilling, D.; Mueller, M.; Harris, A.; Smith, H.; Fazio, G. 2014-07-01 Small asteroids are most likely collisional fragments of larger objects and make up a large fraction of the near-Earth-object (NEO) population. Despite their abundance, little is known about the physical properties of these objects, which is mainly due to their faintness, which also impedes their discovery. We report on Spitzer Space Telescope observations of two small NEOs, both of which are of interest as potential spacecraft targets. We observed NEOs 2009 BD using 25 hrs and 2011 MD using ˜20 hrs of Spitzer Infrared Array Camera Channel 2 time. For each target, we have combined the data into maps in the moving frame of the target, minimizing the background confusion. We did not detect 2009 BD and place an upper limit on its flux density, but we detected 2011 MD as a 2.2σ detection. We have analyzed the data on both objects in a combined model approach, using an asteroid thermophysical model and a model of non-gravitational forces acting on the object. As a result, we are able to constrain the physical properties of both objects. In the case of 2009 BD (Mommert et al. 2014), a wealth of existing astrometry data significantly constrains the physical properties of the object. We find two physically possible solutions. The first solution shows 2009 BD as a 2.9±0.3 m-sized massive rock body (bulk density ρ=2.9±0.5 g cm^{-3}) with an extremely high albedo of 0.85_{-0.10}^{+0.20} that is covered with regolith-like material, causing it to exhibit a low thermal inertia (thermal inertia Γ=30_{-10}^{+20} SI units). The second solution suggests 2009 BD to be a 4±1 m-sized asteroid with p_{V}=0.45_{-0.15}^{+0.35} that consists of a collection of individual bare rock slabs (Γ = 2000±1000 SI units, ρ = 1.7_{-0.4}^{+0.7} g cm^{-3}). We are unable to rule out either solution based on physical reasoning. The preliminary analysis of 2011 MD shows this object as a ˜6 m-sized asteroid with an albedo of ˜0.3. Additional constraints on the physical properties of these objects will be available at the time of the conference (Mommert et al., in preparation). 2009 BD and 2011 MD are the smallest asteroids for which physical properties have been constrained, providing unique insights into a population of asteroids that gives rise to frequent impacts on the Earth and the Moon. Furthermore, both asteroids are among the most easily accessible objects in space. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017DPS....4920408A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017DPS....4920408A">Lunar impact flashes - tracing the NEO size distribution</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Avdellidou, Chrysa; Koschny, Detlef; NELIOTA Team 2017-10-01 Almost 20 years ago, we started to monitor the lunar surface with small telescopes to detect light flashes resulting from the hypervelocity collisions of meteoroids. The initial purpose was to understand the flux of impactors on Earth. The estimation of the flux of near Earth Objects (NEOs) is important not only for the protection of the human civilisation (meter-sized, see Chelyabinsk event in 2013), but also for the protection of the space assets (cm-sized objects). Apart from the NEO flux, the lunar surface helps the study of the impact events per se. The European Space Agency (ESA) is directing and funding lunar observations at 1.2 m Kryoneri telescope in Peloponnese, Greece. This telescope is equipped with a dichroic beam-splitter that directs the light onto two sCMOS cameras, that observe in visible and infrared wavelengths, using Rc and Ic Cousin filters respectively. Currently it is the largest telescope in the world that performs dedicated lunar impact flashes observations. We present the first flash observations in two bands, allowing us to measure flash temperatures for the first time. We find that the temperatures have a range that agrees with the theoretical approaches. Since the temperature can now be calculated, we have a more accurate estimation of the impactor’s mass and the size of the radiated ejecta plume.Having the Moon as a large-scale laboratory, new horizons are set towards the understanding of the nature of impacts, the impactor's material type and the energy partitioning, that is a constant puzzle in impact studies. This can now happen as more impact parameters can be determined and combined, such as the impactor’s mass and speed, flash luminosity, radiating volume, crater size when applicable etc. Future statistics can determine the different lunar regolith properties at different impact sites, especially during a meteoroid stream where the impactors share a common origin and possibly composition. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015A%26A...580A.109D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015A%26A...580A.109D">Infrequent visitors of the Kozai kind: the dynamical lives of 2012 FC71, 2014 EK24, 2014 QD364, and 2014 UR</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> de la Fuente Marcos, C.; de la Fuente Marcos, R. 2015-08-01 Context. Asteroids with semi-major axes very close to that of a host planet can avoid node crossings when their nodal points are at perihelion and at aphelion. This layout protects the asteroids from close encounters, and eventual collisions, with the host planet. Aims: Here, we study the short-term dynamical evolution of four recently discovered near-Earth asteroids (NEAs) - 2012 FC71, 2014 EK24, 2014 QD364, and 2014 UR - that follow very Earth-like orbits. Methods: Our analysis is based on results of direct N-body calculations that use the most updated ephemerides and include perturbations from the eight major planets, the Moon, the barycentre of the Pluto-Charon system, and the three largest asteroids. Results: These four NEAs exhibit an orbital evolution unlike any other known near-Earth object (NEO). Beyond horseshoe, tadpole, or quasi-satellite trajectories, they follow co-orbital passing orbits relative to the Earth within the Kozai domain. Our calculations show that secular interactions induce librations of their relative argument of perihelion with respect to our planet but also to Venus, Mars, and Jupiter. Secular chaos is also present. The size of this transient population is probably large. Conclusions: Although some of these NEAs can remain orbitally stable for many thousands of years, their secular dynamics are substantially more complicated than commonly thought and cannot be properly described within the framework of the three-body problem alone owing to the overlapping of multiple secular resonances. Objects in this group are amongst the most atypical NEOs regarding favourable visibility windows because these are separated in time by many decades or even several centuries. Figures 2, 3, 5, 7, 9, 11, 13, 15, 17, 18, Table 2, and Appendix A are available in electronic form at http://www.aanda.org </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/22520035-grasping-nature-potentially-hazardous-asteroids','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22520035-grasping-nature-potentially-hazardous-asteroids"></a> <a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Perna, D.; Barucci, M. A.; Fornasier, S. Through their delivery of water and organics, near-Earth objects (NEOs) played an important role in the emergence of life on our planet. However, they also pose a hazard to the Earth, as asteroid impacts could significantly affect our civilization. Potentially hazardous asteroids (PHAs) are those that, in principle, could possibly impact the Earth within the next century, producing major damage. About 1600 PHAs are currently known, from an estimated population of 4700 ± 1450. However, a comprehensive characterization of the PHA physical properties is still missing. Here we present spectroscopic observations of 14 PHAs, which we have used to derive their taxonomy,more » meteorite analogs, and mineralogy. Combining our results with the literature, we investigated how PHAs are distributed as a function of their dynamical and physical properties. In general, the “carbonaceous” PHAs seem to be particularly threatening, because of their high porosity (limiting the effectiveness of the main deflection techniques that could be used in space) and low inclination and minimum orbit intersection distance (MOID) with the Earth (favoring more frequent close approaches). V-type PHAs also present low MOID values, which can produce frequent close approaches (as confirmed by the recent discovery of a limited space weathering on their surfaces). We also identified those specific objects that deserve particular attention because of their extreme rotational properties, internal strength, or possible cometary nature. For PHAs and NEOs in general, we identified a possible anti-correlation between the elongation and the rotational period, in the range of P{sub rot} ≈ 5–80 hr. This would be compatible with the behavior of gravity-dominated aggregates in rotational equilibrium. For periods ≳80–90 hr, such a trend stops, possibly under the influence of the YORP effect and collisions. However, the statistics is very low, and further observational and theoretical work is required to characterize such slow rotators.« less </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EJPh...34..383P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EJPh...34..383P">Newtonian-Machian analysis of the neo-Tychonian model of planetary motions</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Popov, Luka 2013-03-01 The calculation of the trajectories in the Sun-Earth-Mars system is performed using two different models, both in the framework of Newtonian mechanics. The first model is the well-known Copernican system, which assumes that the Sun is at rest and that all the planets orbit around it. The second is a less well-known model, developed by Tycho Brahe (1546-1601), according to which the Earth stands still, the Sun orbits around the Earth, and the other planets orbit around the Sun. The term ‘neo-Tychonian system’ refers to the assumption that orbits of distant masses around the Earth are synchronized with the Sun's orbit. It is the aim of this paper to show the kinematical and dynamical equivalence of these systems, under the assumption of Mach's principle. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120014550','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120014550">Multiple NEO Rendezvous Using Solar Sail Propulsion</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Johnson, Les; Alexander, Leslie; Fabisinski, Leo; Heaton, Andy; Miernik, Janie; Stough, Rob; Wright, Roosevelt; Young, Roy 2012-01-01 The NASA Marshall Space Flight Center (MSFC) Advanced Concepts Office performed an assessment of the feasibility of using a near-term solar sail propulsion system to enable a single spacecraft to perform serial rendezvous operations at multiple Near Earth Objects (NEOs) within six years of launch on a small-to-moderate launch vehicle. The study baselined the use of the sail technology demonstrated in the mid-2000 s by the NASA In-Space Propulsion Technology Project and is scheduled to be demonstrated in space by 2014 as part of the NASA Technology Demonstration Mission Program. The study ground rules required that the solar sail be the only new technology on the flight; all other spacecraft systems and instruments must have had previous space test and qualification. The resulting mission concept uses an 80-m X 80-m 3-axis stabilized solar sail launched by an Athena-II rocket in 2017 to rendezvous with 1999 AO10, Apophis and 2001 QJ142. In each rendezvous, the spacecraft will perform proximity operations for approximately 30 days. The spacecraft science payload is simple and lightweight; it will consist of only the multispectral imager flown on the Near Earth Asteroid Rendezvous (NEAR) mission to 433 Eros and 253 Mathilde. Most non-sail spacecraft systems are based on the Messenger mission spacecraft. This paper will describe the objectives of the proposed mission, the solar sail technology to be employed, the spacecraft system and subsystems, as well as the overall mission profile. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017A%26A...598A..52G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017A%26A...598A..52G">Escape of asteroids from the main belt</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Granvik, Mikael; Morbidelli, Alessandro; Vokrouhlický, David; Bottke, William F.; Nesvorný, David; Jedicke, Robert 2017-02-01 Aims: We locate escape routes from the main asteroid belt, particularly into the near-Earth-object (NEO) region, and estimate the relative fluxes for different escape routes as a function of object size under the influence of the Yarkovsky semimajor-axis drift. Methods: We integrated the orbits of 78 355 known and 14 094 cloned main-belt objects and Cybele and Hilda asteroids (hereafter collectively called MBOs) for 100 Myr and recorded the characteristics of the escaping objects. The selected sample of MBOs with perihelion distance q > 1.3 au and semimajor axis a < 4.1 au is essentially complete, with an absolute magnitude limit ranging from HV < 15.9 in the inner belt (a < 2.5 au) to HV < 14.4 in the outer belt (2.5 au < a < 4.1 au). We modeled the semimajor-axis drift caused by the Yarkovsky force and assigned four different sizes (diameters of 0.1, 0.3, 1.0, and 3.0 km) and random spin obliquities (either 0 deg or 180 deg) for each test asteroid. Results: We find more than ten obvious escape routes from the asteroid belt to the NEO region, and they typically coincide with low-order mean-motion resonances with Jupiter and secular resonances. The locations of the escape routes are independent of the semimajor-axis drift rate and thus are also independent of the asteroid diameter. The locations of the escape routes are likewise unaffected when we added a model for Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) cycles coupled with secular evolution of the rotation pole as a result of the solar gravitational torque. A Yarkovsky-only model predicts a flux of asteroids entering the NEO region that is too high compared to the observationally constrained flux, and the discrepancy grows larger for smaller asteroids. A combined Yarkovsky and YORP model predicts a flux of small NEOs that is approximately a factor of 5 too low compared to an observationally constrained estimate. This suggests that the characteristic timescale of the YORP cycle is longer than our canonical YORP model predicts. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017DPS....4910306S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017DPS....4910306S">Short arc orbit determination and Gaia alerts</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Spoto, Federica; Tanga, Paolo; Del Vigna, Alessio; Carry, Benoit; Thuillot, William; David, Pedro; Mignard, Francois; Milani, Andrea; Tommei, Giacomo 2017-10-01 Since October 2016, the short term (ST) processing of Solar System Objects (SSOs) by Gaia is up and running, and it has produced almost 600 alerts. A crucial point in the chain is the possibility of performing a short arc orbit determination as soon as the object has been detected, which allows the follow up of the object from the ground.The method we present has been recentely developed for two mainreasons: 1) search for imminent impactors within the NEO - Confirmation Page(imminent impactors are asteroids that could impact the Earth infew days from their discovery) 2) validation of the SSO-ST Gaia pipeline.We show some good confirmations on objects that could have been discovered by Gaia, and some properties of the Gaia astrometry for the short term. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AIPC.1208..430B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AIPC.1208..430B">Challenges of Deflecting an Asteroid or Comet Nucleus with a Nuclear Burst</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Bradley, P. A.; Plesko, C. S.; Clement, R. R. C.; Conlon, L. M.; Weaver, R. P.; Guzik, J. A.; Pritchett-Sheats, L. A.; Huebner, W. F. 2010-01-01 There are many natural disasters that humanity has to deal with over time. These include earthquakes, tsunamis, hurricanes, floods, asteroid strikes, and so on. Some of these disasters occur slowly enough that some advance warning is possible for affected areas. In this case, the response is to evacuate the affected area and deal with the damage later. The Katrina and Rita hurricane evacuations on the U.S. Gulf Coast in 2005 demonstrated the chaos that can result from such a response. In contrast with other natural disasters, it is likely that an asteroid or comet nucleus on a collision course with Earth will be detected with enough warning time to possibly deflect it away. Thanks to Near-Earth Object (NEO) surveys, people are working towards a goal of cataloging at least 90% of all near-Earth objects with diameters larger than ~140 meters in the next fifteen years. The important question then, is how to mitigate the threat from an asteroid or comet nucleus found to be on a collision course with Earth. In this paper, we briefly review some possible deflection methods, describe their good and bad points, and then embark on a more detailed description of using nuclear munitions in a standoff mode to deflect the asteroid or comet nucleus before it can hit Earth. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014MNRAS.439.3704M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014MNRAS.439.3704M">Near-Earth object 2012XJ112 as a source of bright bolides of achondritic nature</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Madiedo, José M.; Trigo-Rodríguez, Josep M.; Williams, Iwan P.; Konovalova, Natalia; Ortiz, José L.; Castro-Tirado, Alberto J.; Pastor, Sensi; de los Reyes, José A.; Cabrera-Caño, Jesús 2014-04-01 We analyse the likely link between the recently discovered near-Earth object 2012XJ112 and a bright fireball observed over the south of Spain on 2012 December 27. The bolide, with an absolute magnitude of -9 ± 1, was simultaneously imaged during the morning twilight from two meteor stations operated by the SPanish Meteor Network (SPMN). It was also observed by several casual witnesses. The emission spectrum produced during the ablation of the meteoroid in the atmosphere was also recorded. From its analysis, the chemical nature of this particle was inferred. Although our orbital association software identified several potential parent bodies for this meteoroid, the analysis of the evolution of the orbital elements performed with the MERCURY 6 symplectic integrator supports the idea that NEO 2012XJ112 is the source of this meteoroid. The implications of this potential association are discussed here. In particular, the meteoroid bulk chemistry is consistent with a basaltic achondrite, and this emphasizes the importance to deduce from future Earth approaches the reflectance spectrum and taxonomic nature of 2012XJ112. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140010940','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140010940">Human Exploration of Near-Earth Asteroids</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Abell, Paul 2013-01-01 A major goal for NASA's human spaceflight program is to send astronauts to near-Earth asteroids (NEA) in the coming decades. Missions to NEAs would undoubtedly provide a great deal of technical and engineering data on spacecraft operations for future human space exploration while conducting in-depth scientific examinations of these primitive objects. However, before sending human explorers to NEAs, robotic investigations of these bodies would be required to maximize operational efficiency and reduce mission risk. These precursor missions to NEAs would fill crucial strategic knowledge gaps concerning their physical characteristics that are relevant for human exploration of these relatively unknown destinations. Dr. Paul Abell discussed some of the physical characteristics of NEOs that will be relevant for EVA considerations, reviewed the current data from previous NEA missions (e.g., Near-Earth Asteroid Rendezvous (NEAR) Shoemaker and Hayabusa), and discussed why future robotic and human missions to NEAs are important from space exploration and planetary defense perspectives. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-ARC-20140717-AAV2687.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-ARC-20140717-AAV2687.html">2014 Summer Series - Rusty Schweickart - Dinosaur Syndrome Avoidance Project: How Gozit?</a> <a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2014-07-17 The 2013 Chelyabinsk meteor demonstrated that grave uncertainties exist pertaining to near-Earth objects (NEOs). Although the impact rate for dangerous asteroids is relatively low, the consequences of such an event are severe. Apollo Astronaut Rusty Schweickart, will talk about our prospects of avoiding the same fate as the dinosaurs. He will review the status of the global efforts to protect life on the planet from the devastation of large asteroid impacts. He will also discuss both the technical and geopolitical components of the challenge of preventing future asteroid impacts. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EPSC...11..398R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EPSC...11..398R">How Many Ch-Class NEOs Do We Expect?</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Rivkin, A. S.; DeMeo, F. E. 2017-09-01 The Ch spectral class is thought to contain objects that have water in their minerals, and they are of great interest to scientists and the nascent asteroid mining industry. We use models of asteroid delivery to near-Earth space and measurements of the different compositions of asteroids to estimate there should be at least 20 Ch asteroids larger than 100 m that are more accessible than the Moon, though we note that there are some untested assumptions that lead to that number. Further work must be done to identify the specific Ch asteroids. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018EUCAS..10..123V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018EUCAS..10..123V">Genetic algorithms for GNC settings and DACS design application to an asteroid Kinetic Impactor</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Vernis, P.; Oliviero, V. 2018-06-01 This paper deals with an application of Genetic Algorithm (GA) tools in order to perform and optimize the settings phase of the Guidance, Navigation, and Control (GNC) data set for the endgame phase of a Kinetic Impactor (KI) targeting a medium-size Near Earth Object (NEO). A coupled optimization of the GNC settings and of the GC-oriented design of the Divert and Attitude Control System (DACS) is also proposed. The illustration of the developed principles is made considering the NEOShield study frame. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20150004659&hterms=Hair&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DHair','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20150004659&hterms=Hair&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DHair">Integrated Instrument Simulator Suites for Earth Science</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Tanelli, Simone; Tao, Wei-Kuo; Matsui, Toshihisa; Hostetler, Chris; Hair, Johnathan; Butler, Carolyn; Kuo, Kwo-Sen; Niamsuwan, Noppasin; Johnson, Michael P.; Jacob, Joseph C.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20150004659'); toggleEditAbsImage('author_20150004659_show'); toggleEditAbsImage('author_20150004659_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20150004659_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20150004659_hide"> 2012-01-01 The NASA Earth Observing System Simulators Suite (NEOS3) is a modular framework of forward simulations tools for remote sensing of Earth's Atmosphere from space. It was initiated as the Instrument Simulator Suite for Atmospheric Remote Sensing (ISSARS) under the NASA Advanced Information Systems Technology (AIST) program of the Earth Science Technology Office (ESTO) to enable science users to perform simulations based on advanced atmospheric and simple land surface models, and to rapidly integrate in a broad framework any experimental or innovative tools that they may have developed in this context. The name was changed to NEOS3 when the project was expanded to include more advanced modeling tools for the surface contributions, accounting for scattering and emission properties of layered surface (e.g., soil moisture, vegetation, snow and ice, subsurface layers). NEOS3 relies on a web-based graphic user interface, and a three-stage processing strategy to generate simulated measurements. The user has full control over a wide range of customizations both in terms of a priori assumptions and in terms of specific solvers or models used to calculate the measured signals.This presentation will demonstrate the general architecture, the configuration procedures and illustrate some sample products and the fundamental interface requirements for modules candidate for integration. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010045257&hterms=Xxxii&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DXxxii','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010045257&hterms=Xxxii&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DXxxii">The Near-Earth Space Surveillance (NESS) Mission: Discovery, Tracking, and Characterization of Asteroids, Comets, and Artificial Satellites with a Microsatellite</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Hildebrand, A. R.; Carroll, K. A.; Balam, D. D.; Cardinal, R. D.; Matthews, J. M.; Kuschnig, R.; Walker, G. A. H.; Brown, P. G.; Tedesco, E. F.; Worden, S. P. 2001-01-01 The Near-Earth Space Surveillance (NESS) Mission, a microsatellite dedicated to observing near-Earth (NEO) and interior-to-the-Earth (IEO)asteroids and comets plus artificial satellites, is currently being studied under contract to the Canadian Space Agency. Additional information is contained in the original extended abstract. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AcAau.123...51H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AcAau.123...51H">Campaign-level dynamic network modelling for spaceflight logistics for the flexible path concept</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Ho, Koki; de Weck, Olivier L.; Hoffman, Jeffrey A.; Shishko, Robert 2016-06-01 This paper develops a network optimization formulation for dynamic campaign-level space mission planning. Although many past space missions have been designed mainly from a mission-level perspective, a campaign-level perspective will be important for future space exploration. In order to find the optimal campaign-level space transportation architecture, a mixed-integer linear programming (MILP) formulation with a generalized multi-commodity flow and a time-expanded network is developed. Particularly, a new heuristics-based method, a partially static time-expanded network, is developed to provide a solution quickly. The developed method is applied to a case study containing human exploration of a near-Earth object (NEO) and Mars, related to the concept of the Flexible Path. The numerical results show that using the specific combinations of propulsion technologies, in-situ resource utilization (ISRU), and other space infrastructure elements can reduce the initial mass in low-Earth orbit (IMLEO) significantly. In addition, the case study results also show that we can achieve large IMLEO reduction by designing NEO and Mars missions together as a campaign compared with designing them separately owing to their common space infrastructure pre-deployment. This research will be an important step toward efficient and flexible campaign-level space mission planning. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...832..127H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...832..127H">Thermal Tomography of Asteroid Surface Structure</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Harris, Alan W.; Drube, Line 2016-12-01 Knowledge of the surface thermal inertia of an asteroid can provide insight into its surface structure: porous material has a lower thermal inertia than rock. We develop a means to estimate thermal inertia values of asteroids and use it to show that thermal inertia appears to increase with spin period in the case of main-belt asteroids (MBAs). Similar behavior is found on the basis of thermophysical modeling for near-Earth objects (NEOs). We interpret our results in terms of rapidly increasing material density and thermal conductivity with depth, and provide evidence that thermal inertia increases by factors of 10 (MBAs) to 20 (NEOs) within a depth of just 10 cm. Our results are consistent with a very general picture of rapidly changing material properties in the topmost regolith layers of asteroids and have important implications for calculations of the Yarkovsky effect, including its perturbation of the orbits of potentially hazardous objects and those of asteroid family members after the break-up event. Evidence of a rapid increase of thermal inertia with depth is also an important result for studies of the ejecta-enhanced momentum transfer of impacting vehicles (“kinetic impactors”) in planetary defense. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/22661014-thermal-tomography-asteroid-surface-structure','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22661014-thermal-tomography-asteroid-surface-structure">THERMAL TOMOGRAPHY OF ASTEROID SURFACE STRUCTURE</a> <a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Harris, Alan W.; Drube, Line, E-mail: alan.harris@dlr.de Knowledge of the surface thermal inertia of an asteroid can provide insight into its surface structure: porous material has a lower thermal inertia than rock. We develop a means to estimate thermal inertia values of asteroids and use it to show that thermal inertia appears to increase with spin period in the case of main-belt asteroids (MBAs). Similar behavior is found on the basis of thermophysical modeling for near-Earth objects (NEOs). We interpret our results in terms of rapidly increasing material density and thermal conductivity with depth, and provide evidence that thermal inertia increases by factors of 10 (MBAs) tomore » 20 (NEOs) within a depth of just 10 cm. Our results are consistent with a very general picture of rapidly changing material properties in the topmost regolith layers of asteroids and have important implications for calculations of the Yarkovsky effect, including its perturbation of the orbits of potentially hazardous objects and those of asteroid family members after the break-up event. Evidence of a rapid increase of thermal inertia with depth is also an important result for studies of the ejecta-enhanced momentum transfer of impacting vehicles (“kinetic impactors”) in planetary defense.« less </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003DPS....35.4111D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003DPS....35.4111D">Cost-Effective NEO Characterization Using Solar Electric Propulsion (SEP)</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Dissly, R. W.; Reinert, R.; Mitchell, S. 2003-05-01 We present a cost-effective multiple NEO rendezvous mission design optimized around the capabilities of Ball's 200-kg NEOX Solar Electric Propelled microsatellite. The NEOX spacecraft is 3-axis stabilized with better-than 1 milliradian pointing accuracy to serve as an excellent imaging platform; its DSN compatible telecommunications subsystem can support a 6.4-kbps downlink rate at 3 AU earth range. The spacecraft mass is <200kg at launch to allow launch as a cost-effective secondary payload. It uses proven SEP technology to provide 12km/s of Delta-V, which enables multiple rendezvous' in a single mission. Cost-effectiveness is optimized by launch as a secondary payload (e.g., Ariane-5 ASAP) or as a multiple manifest on a single dedicated launch vehicle (e.g., 4 on a Delta-II 2925). Following separation from the LV, we describe a candidate mission profile that minimizes cost by using the spacecraft's 12km/s of SEP Delta-V to allow orbiting up to 4 separate NEO's. Orbiting as opposed to flying by augments the mission's science return by providing the NEO mass and by allowing multiple phase angle imaging. The NEOX Spacecraft has the capability to support a 20kg payload drawing 100W average during SEP cruise, with >1kW available during the NEO orbital phase when the SEP thrusters are not powered. We will present a candidate payload suite that includes a visible/NIR imager, a laser altimeter, and a set of small, self-righting surface probes that can be used to assess the geophysical state of the object surface and near-surface environments. The surface probe payload notionally includes a set of cameras for imaging the body surface at mm-scale resolution, an accelerometer package to measure surface mechanical properties upon probe impact, a Langmuir probe to measure the electrostatic gradient immediately above the object surface, and an explosive charge that can be remotely detonated at the end of the surface mission to excavate an artificial crater that can be remotely observed from the orbiting spacecraft. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active">13</li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active">14</li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017Icar..285...83F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017Icar..285...83F">Orbit and size distributions for asteroids temporarily captured by the Earth-Moon system</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Fedorets, Grigori; Granvik, Mikael; Jedicke, Robert 2017-03-01 As a continuation of the work by Granvik et al. (2012), we expand the statistical treatment of Earth's temporarily-captured natural satellites from temporarily-captured orbiters (TCOs, i.e., objects which make at least one orbit around the Earth) to the newly redefined subpopulation of temporarily-captured flybys (TCFs). TCFs are objects that while being gravitationally bound fail to make a complete orbit around the Earth while on a geocentric orbit, but nevertheless approach the Earth within its Hill radius. We follow the trajectories of massless test asteroids through the Earth-Moon system and record the orbital characteristics of those that are temporarily captured. We then carry out a steady-state analysis utilizing the novel NEO population model by Granvik et al. (2016). We also investigate how an quadratic distribution at very small values of e⊙ and i⊙ affects the predicted population statistics of Earth's temporarily-captured natural satellites. The steady-state population in both cases (constant and quadratic number distributions inside the e and i bins) is predicted to contain a slightly reduced number of meter-sized asteroids compared to the values of the previous paper. For the combined TCO/TCF population, we find the largest body constantly present on a geocentric orbit to be on the order of 80 cm in diameter. In the phase space, where the capture is possible, the capture efficiency of TCOs and TCFs is O(10-6 -10-4) . We also find that kilometer-scale asteroids are captured once every 10 Myr. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008epsc.conf..725M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008epsc.conf..725M">The contribution of comets in Near-Earth Object and Main Belt populations and the role of collisions in the physical properties of members of these populations.</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Michel, P. 2008-09-01 The population of Near-Earth Objects (NEOs) is composed of small bodies of various origins. Groundbased observational programs have been developed to perform their inventory and to determine their physical properties. However, these observations contain many biases and the total population of NEOs with diameters down to a few hundreds of meters has not been identified yet. In recent years, the main sources of NEOs have been characterized [1]. Most of these bodies come from the asteroid main belt and the Jupiter-family comets and their source regions are linked to transport mechanisms (mean motion and secular resonances, slow diffusion mechanisms) to the NEO-space. It has then been possible to construct a complete model of the steady-state orbital, size and albedo distribution of NEOs and to determine the level of contribution of each of their sources, including the contribution of Jupiter-family comets. However, nothing is known regarding the contribution of longperiod comets. Physical observations have been conducted in order to identify potential dormant or extinct comets among small bodies in the NEO population and to determine the fraction of "comet candidates within the total NEO population. Combining the results of these observations with our model of NEO population to evaluate source region probabilities [1], it was found that 8 +/- 5% of the total asteroid-like NEO population may have originated as comets from the outer Solar System [2]. In the population of Main Belt (MB) asteroids, three members are known to display transient comet-like physical characteristics, including prolonged periods of dust emission leading to the formation of radiation pressure-swept tails [3]. These physical properties are most naturally explained as the result of sub-limation of near-surface ice from what are, dynamically, mainbelt asteroids (hence the name "main-belt comets" (MBCs) or, equivalently "icy asteroids"). No pausible dynamical path to the asteroid belt from the cometary reservoirs in the Oort cloud or Kuiper belt has been established. Thus, we may have an unsuspected icy region closer to the Sun than expected. However, it has also been suggested that numerous comets may have been captured during a violent period of planetary orbital evolution in the early stages of our Solar System [4]. Most of these bodies experience collisions during their lifetime, which can either disrupt them or modify their physical properties. In particular, collisions are suspected to be the triggering mechanism for the activation of MBCs. Thus the collisional process needs a good understanding in order to determine its contribution in the evolution of these small bodies, as a function of their physical properties. We have recently made a major improvement in the simulations of a small body disruption by introducing a model of fragmentation of porous material which will allows us to study the impact process on cometary bodies [5]. Moreover, for bodies dominated by gravity, our simulations includes the explicit computation of the formation of aggregates during the gravitational reaccumulation of small fragments, allowing us to obtain information on their spin, the number of boulders composing them or lying on their surface, and their shape. We will present the first and preliminary results of this process taking as examples some asteroid families that we reproduced successfully with our previous simulations [6], [7], [8], [9], [10], and their possible implications on the properties of small bodies generated by a disruption. Such information can for instance be compared with data provided by the Japanese space mission Hayabusa of the asteroid Itokawa, a body now understood to be a fragment of a larger parent body. For the population of comets, improving our understanding of their collisional response can then allow us to better characterize their collisional evolution, lifetime and other properties [11] which can have some implications on their contribution in "asteroidal" populations. It is also clear that future space missions to small bodies devoted to precise insitu analysis and sample return will allow us to improve our understanding on the physical properties of these objects, and to check whether our theoretical and numerical works are valid. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ASPC..495..227O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ASPC..495..227O">A Test-Bed Configuration: Toward an Autonomous System</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Ocaña, F.; Castillo, M.; Uranga, E.; Ponz, J. D.; TBT Consortium 2015-09-01 In the context of the Space Situational Awareness (SSA) program of ESA, it is foreseen to deploy several large robotic telescopes in remote locations to provide surveillance and tracking services for man-made as well as natural near-Earth objects (NEOs). The present project, termed Telescope Test Bed (TBT) is being developed under ESA's General Studies and Technology Programme, and shall implement a test-bed for the validation of an autonomous optical observing system in a realistic scenario, consisting of two telescopes located in Spain and Australia, to collect representative test data for precursor NEO services. In order to fulfill all the security requirements for the TBT project, the use of a autonomous emergency system (AES) is foreseen to monitor the control system. The AES will monitor remotely the health of the observing system and the internal and external environment. It will incorporate both autonomous and interactive actuators to force the protection of the system (i.e., emergency dome close out). </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015HiA....16..478M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015HiA....16..478M">NEOShield - A global approach to NEO Impact Threat Mitigation</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Michel, Patrick 2015-03-01 NEOShield is a European-Union funded project coordinated by the German Aero-space Center, DLR, to address near-Earth object (NEO) impact hazard mitigation issues. The NEOShield consortium consists of 13 research institutes, universities, and industrial partners from 6 countries and includes leading US and Russian space organizations. The project is funded for a period of 3.5 years from January 2012 with a total of 5.8 million euros. The primary aim of the project is to investigate in detail promising mitigation techniques, such as the kinetic impactor, blast deflection, and the gravity tractor, and devise feasible demonstration missions. Options for an international strategy for implementation when an actual impact threat arises will also be investigated. The NEOShield work plan consists of scientific investigations into the nature of the impact hazard and the physical properties of NEOs, and technical and engineering studies of practical means of deflecting NEOs. There exist many ideas for asteroid deflection techniques, many of which would require considerable scientific and technological development. The emphasis of NEOShield is on techniques that are feasible with current technology, requiring a minimum of research and development work. NEOShield aims to provide detailed designs of feasible mitigation demonstration missions, targeting NEOs of the kind most likely to trigger the first space-based mitigation action. Most of the asteroid deflection techniques proposed to date require physical contact with the threatening object, an example being the kinetic impactor. NEOShield includes research into the mitigation-relevant physical properties of NEOs on the basis of remotely-sensed astronomical data and the results of rendezvous missions, the observational techniques required to efficiently gather mitigation-relevant data on the dynamical state and physical properties of a threatening NEO, and laboratory investigations using gas guns to fire projectiles into asteroid regolith analog materials. The gas-gun investigations enable state-of-the-art numerical models to be verified at small scales. Computer simulations at realistic NEO scales are used to investigate how NEOs with a range of properties would respond to a pulse of energy applied in a deflection attempt. The technical work includes the development of crucial technologies, such as the autonomous guidance of a kinetic impactor to a precise point on the surface of the target, and the detailed design of realistic missions for the purpose of demonstrating the applicability and feasibility of one or more of the techniques investigated. Theoretical work on the blast deflection method of mitigation is designed to probe the circumstances in which this last line of defense may be the only viable option and the issues relating to its deployment. A global response campaign roadmap will be developed based on realistic scenarios presented, for example, by the discovery of an object such as 99942 Apophis or 2011 AG5 on a threatening orbit. The work will include considerations of the timeline of orbit knowledge and impact probability development, reconnaissance observations and fly-by or rendezvous missions, the political decision to mount a mitigation attempt, and the design, development, and launch of the mitigation mission. Collaboration with colleagues outside the NEOShield Consortium involved in complementary activities (e.g. under the auspices of the UN, NASA, or ESA) is being sought in order to establish a broad international strategy. We present a brief overview of the history and planned scope of the project, and progress made to date. The NEOShield project (http://www.neoshield.net) has received funding from the European Union Seventh Framework Program (FP7/2007-2013) under Grant Agreement no. 282703. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUSM.P32A..07S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUSM.P32A..07S">Migration of Icy Bodies to the Terrestrial Planets</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Sergei, I. I.; Mather, J. C.; Marov, M. Y. 2006-05-01 In our opinion [1-2], some trans-Neptunian objects (TNOs) and planetesimals in the feeding zone of the giant planets with diameters up to 1000 km could be formed directly by the compression of large rarefied dust condensations, but not by the accretion of smaller solid planetesimals. Migration processes of small bodies from the outer regions of the solar system, including the Edgeworth-Kuiper belt, could be responsible for the delivery of the original matter (mainly volatiles) to the terrestrial planets and thus to give rise to the life origin. As migration of TNOs to Jupiter's orbit was studied by several authors, we integrated the orbital evolution of 30,000 Jupiter-crossing objects under the gravitational influence of planets [3]. A few considered objects got Earth-crossing orbits with aphelion distances Q<4.2 AU and moved in such orbits for more than 1 Myr (up to tens or even hundreds of Myrs). Collisions of cometary objects with the terrestrial planets from the Encke- type orbits with aphelia located inside the orbit of Jupiter are assumed to play a greater role than direct impacts from the Jupiter-crossing orbits. It may be possible that the fraction of 1-km former TNOs among near- Earth objects (NEOs) can exceed several tens of percents or most of former TNOs that had got NEO orbits disintegrated into mini-comets and dust during a smaller part of their dynamical lifetimes if these lifetimes are not small. Our estimates show that the amount of icy planetesimals impacted on the Earth during formation of the giant planets is of the order of mass of water in the Earth oceans if the total mass of these planetesimals was about 100 Earth masses. Mars acquired more water per unit of mass of a planet than Earth. During the following 4 Gyr the effectiveness of transport was much less. We integrated [4-5] the orbital evolution of 12,000 dust particles. Probabilites of collisions of particles started from Jupiter-family comets were maximum at diameter d about 100 microns and can be smaller by several orders of magnitude for other d. These maximum probabilities can be 1-2 orders of magnitude greater than the probabilities for comets which produced these particles. The dust particles could be most efficient in the delivery of organic or even biogenic matter to the Earth, because they experience substantially weaker heating when passing through the atmosphere [6]. References: [1] Ipatov S.I. (2001) LPSC, #1165. [2] Ipatov S.I. (2004) "The Search for Other Worlds", ed. by S.S. Holt and D. Deming, AIP Conference Proceedings, 713, 277-280. [3] Ipatov S.I. and Mather J.C. (2004) Annals of the New York Acad. of Sciences, 1017, 46-65. [4] Ipatov S.I., Mather J.C., and Taylor P. (2004) Annals of the New York Acad. of Sciences, 1017, 66-80. [5] Ipatov S.I. and Mather J.C. (2006) Advances in Space Research, in press. [6] Marov M.Ya. and Ipatov S.I. (2005) Solar System Research, 39, 374-380. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Ap%26SS.361..358D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Ap%26SS.361..358D">Homing in for New Year: impact parameters and pre-impact orbital evolution of meteoroid 2014 AA</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> de la Fuente Marcos, C.; de la Fuente Marcos, R.; Mialle, P. 2016-11-01 On 2008 October 7, small asteroid 2008 TC3 turned itself into the parent body of the first meteor ever to be predicted before entering the Earth's atmosphere. Over five years later, the 2014 AA event became the second instance of such an occurrence. The uncertainties associated with the pre-impact orbit of 2008 TC3 are relatively small because thousands of observations were made during the hours preceding the actual meteor airburst. In sharp contrast, 2014 AA was only observed seven times before impact and consequently its trajectory is somewhat uncertain. Here, we present a recalculation of the impact parameters—location and timing—of this meteor based on infrasound recordings. The new values—(λ_{impact}, φ_{impact}, t_{impact}) = (-44°, +11°, 2456659.618 JD UTC)—and their uncertainties together with Monte Carlo and N-body techniques, are applied to obtain an independent determination of the pre-impact orbit of 2014 AA: a=1.1623 AU, e=0.2116, i=1.4156°, Ω =101.6086°, and ω=52.3393°. Our orbital solution is used to investigate the possible presence of known near-Earth objects (NEOs) moving in similar orbits. Among the objects singled out by this search, the largest is 2013 HO_{11} with an absolute magnitude of 23.0 (diameter 75-169 m) and a MOID of 0.006 AU. Prior to impact, 2014 AA was subjected to a web of overlapping secular resonances and it followed a path similar to those of 2011 GJ3, 2011 JV_{10}, 2012 DJ_{54}, and 2013 NJ4. NEOs in this transient group have their orbits controlled by close encounters with the Earth-Moon system at perihelion and Mars at aphelion, perhaps constituting a dynamical family. Extensive comparison with other studies is also presented. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4832527I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4832527I">The NEOShield-2 EU Project - The first year of the Italian contribution</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Ieva, Simone; Dotto, Elisabetta; Mazzotta Epifani, Elena; Di Paola, Andrea; Speziali, Roberto; Lazzarin, Monica; Bertini, Ivano; Barucci, Maria Antonieta; Perna, Davide; Lazzaro, Daniela; Silva, Sergio; Monteiro, Filipe; Perozzi, Ettore; Micheli, Marco; Cortese, Matteo 2016-10-01 The population of Near Earth Asteroids (NEAs) is responsible for a continuous flux of impactors with our planet. To date, more than 14500 NEAs are known, with a current discovery rate of ˜1500 objects/year.The NEA population show a great diversity in terms of composition and physical properties: (different shapes, rotational states, rotational periods...). NEA diversity is also emphasized by the different taxonomic types found within the population that give some hints about the NEA surface composition.The study of their physical nature is compelling in view of the potential hazard posed to our planet, since it has been acknowledged that whatever the mitigation scenario, it strongly depends upon the composition of the impactor. Unfortunately, only less than 15% of them have been physically characterized, and at the current discovery rate the situation is becoming progressively worse.Within the framework of the Horizon 2020 program, the European Commission promoted the study of NEAs by approving and financing the NEOShield-2 project (2015-2017). One of the main aims of the NEOShield-2 project is to undertake an extensive observational campaign to provide physical and compositional characterization of a large number of NEAs in the 50-300 m size range.INAF-OAR and Padova University, the Italian contributors to the NEOShield-2 project, are responsible for the Task 10.2.1 'Colours and Phase function', with the aim to acquire photometric measurements for a wide sample of NEOs. An operational interface is maintained together with the ESA SSA-NEO Coordination Centre (NEOCC) in order to optimize observations devoted to physical characterization.We will present the results of the first year of the Italian contribution to the project on i) phase function analysis, ii) surface colors and iii) preliminary taxonomical classification and the statistical analysis of the data obtained from several telescopes around the world.This research has been funded with support from the European Commission (grant agreement no: 640351 H2020- PROTEC-2014 - Access technologies and characterisation for Near Earth Objects (NEOs). </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMED34A..05P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMED34A..05P">International Astronomical Search Collaboration: An Online Student-Based Discovery Program in Astronomy (Invited)</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Pennypacker, C.; Miller, P. 2009-12-01 The past 15 years has seen the development of affordable small telescopes, advanced digital cameras, high speed Internet access, and widely-available image analysis software. With these tools it is possible to provide student programs where they make original astronomical discoveries. High school aged students, even younger, have discovered Main Belt asteroids (MBA), near-Earth objects (NEO), comets, supernovae, and Kuiper Belt objects (KBO). Student-based discovery is truly an innovative way to generate enthusiasm for learning science. The International Astronomical Search Collaboration (IASC = “Isaac”) is an online program where high school and college students make original MBA discoveries and important NEO observations. MBA discoveries are reported to the Minor Planet Center (Harvard) and International Astronomical Union. The NEO observations are included as part of the NASA Near-Earth Object Program (JPL). Provided at no cost to participating schools, IASC is centered at Hardin-Simmons University (Abilene, TX). It is a collaboration of the University, Lawrence Hall of Science (University of California, Berkeley), Astronomical Research Institute (ARI; Charleston, IL), Global Hands-On Universe Association (Portugal),and Astrometrica (Austria). Started in Fall 2006, IASC has reached 135 schools in 14 countries. There are 9 campaigns per year, each with 15 schools and lasting 45 days. Students have discovered 150 MBAs and made > 1,000 NEO observations. One notable discovery was 2009 BD81, discovered by two high school teachers and a graduate student at the Bulgarian Academy of Science. This object, about the size of 3 football fields, crosses Earth’s orbit and poses a serious impact risk. Each night with clear skies and no Moon, the ARI Observatory uses its 24" and 32" prime focus telescopes to take images along the ecliptic. Three images are taken of the same field of view (FOV) over a period of 30 minutes. These are bundled together and placed online at the IASC home site (iasc.hsutx.edu) into the participating school folders. In the morning, the students download their image sets, analyzing the set using the software Astrometrica. The software aligns the images using stars in the FOV then blinks them back and forth. The students easily see the asteroids moving in the background. Astrometrica records the times and celestial coordinates into a report that is forwarded to the Minor Planet Center. IASC is a volunteer-managed program. It has 17 volunteers from 6 countries. They run 9 campaigns per year for 135 schools, although the full capacity is 16 serving 240 schools world-wide. In addition to search campaigns open to any interested school, there have been dedicated campaigns including: 1) All-China Asteroid Search Campaign National Astronomical Observatory of China 2) All-Africa Asteroid Search Campaign South African Astronomical Observatory and Space School Africa 3) All-Texas Asteroid Search Campaign Texas Regional Collaboratives (University of Texas, Austin) Future plans for IASC include new campaigns searching for objects other than MBAs. These include comets, KBOs, supernovae, and active galactic nuclei. Students will also work on variable stars and asteroid light curves, and search for exoplanets. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020030023','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020030023">Solar System Research with the Spacewatch 1.8-m Telescope</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> McMillan, Robert S. 2001-01-01 During this grant period, the 1.8-m Spacewatch telescope was put into routine operation to search for asteroids and comets ranging in location from near-Earth space to regions beyond the orbit of Neptune. All of these classes of objects can be detected simultaneously with our uniform scanning procedures. We are studying near Earth objects (NEOs), main belt asteroids, comets, Centaurs, and trans-Neptunian objects (TNOs), as well as the interrelationships of these classes and their bearing on the origin and evolution of the solar system. The Spacewatch 1.8-meter telescope is sensitive to V(mag) < 22.6 in sidereal scanning mode and is able to reach even fainter in longer 'staring' exposures, with a field of view 0.5 degrees square. These faint limits make the operation of the Spacewatch 1.8-m telescope complementary to asteroid surveys being done by other groups. Specifically, EAs smaller than 100 m in diameter and small main belt asteroids can be found, as well as more distant objects such as Centaurs/Scattered Disk Objects (SDOs) and TNOs. The 1.8-m telescope is also being used to do recoveries and astrometry of recently-discovered asteroids that subsequently become too faint for the other groups before good orbits are established. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017DPS....4911208B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017DPS....4911208B">Update on Spacewatch Observations of Near-Earth Objects</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Brucker, Melissa; McMillan, Robert S.; Bressi, Terry; Larsen, Jeff; Mastaler, Ron; Read, Mike; Scotti, Jim; Tubbiolo, Andrew 2017-10-01 Spacewatch performs targeted astrometric follow-up of near-Earth objects, primarily asteroids (NEAs), to improve knowledge of their orbits. We have a noteworthy history of asteroid and comet observations beginning in 1984 as the first survey to use CCDs to scan the sky for asteroids and comets. Currently, we measure simultaneous astrometry and photometry of observations during an average of 24 nights per lunation (dark and gray time) as the exclusive users of a 1.8-m telescope and a 0.9-m telescope on Kitt Peak. In addition, we use bright time on the 2.3-m Bok Telescope and the 4-m Mayall Telescope on Kitt Peak to chase fainter targets. Continued astrometric follow-up helps to prevent potentially hazardous objects and scientifically interesting NEAs from becoming lost.We prioritize virtual impactors, MPC confirmation page objects, potentially hazardous asteroids (PHAs) with close approaches within 0.03 AU in the next 30 years, upcoming radar targets with astrometry requests, Yarkovsky effect candidates, NEAs with existing characterization data (WISE, Spitzer, SMASS, MANOS), possible spacecraft destinations (NHATS), and requests from the community.In mid October 2015, we switched from survey mode to targeted astrometry on the 0.9-m telescope. From 2015 October 15 through 2017 June 29 (1.7yr), Spacewatch (observatory codes 291, 691, and ^695) had 20951 MPC-accepted NEO lines of astrometry corresponding to measurements of 2647 different NEOs. This includes 4801 PHA lines of astrometry corresponding to 426 different PHAs, of which 223 lines were at apparent magnitudes V>=22.5. We observed 43% of all NEAs and 52% of all unnumbered NEAs that were observed by any observatory during that period. We observed 50% of all PHAs and 64% of all unnumbered PHAs observed during that period. These statistics do not include submitted measurements of confirmation page objects that were not confirmed as NEAs.Support of Spacewatch is from NASA/NEOO grants, the Lunar and Planetary Laboratory, Steward Observatory, Kitt Peak National Observatory, the Brinson Foundation of Chicago, IL, the estates of R. S. Vail and R. L. Waland, and other private donors. We are also indebted to the MPC and JPL for their web services. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014RMxAC..44R.215R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014RMxAC..44R.215R">Brazilian Participations in the International Astronomical Search Collaboration</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Rojas, G. A.; Dalla-Costa, L. J.; Kalmus, A. T.; Kroth, E. C.; Matos, M. F.; Silva, A. L.; Silva, G. G. 2014-10-01 International Astronomical Search Collaboration (IASC) is an international educational project between universities, schools, observatories and research institutions. Its main objective is to enroll high school and college students in the monitoring and discovery of asteroids and Near Earth Objects (NEOs), especially Potentially Hazardous Asteroids. The methodology consists in the analysis of astronomical images obtained in several observatories in North America and Hawaii. The images are distributed throughout the school network and the results must be delivered in a 72-hour timeframe. Since 2010 Brazilian universities and schools have joined IASC, resulting in over a dozen new asteroids found (3 of them NEOs), and hundreds of measurements for already known asteroids. A major event in this collaboration was the All-Brazil Asteroid Search Campaign, which was conducted in September 2012. 2013 marks the fourth year of Brazilian participations in IASC, with one important milestone: the third straight appearance of a Brazilian institution in the Pan-STARRS campaign, which uses the PS1 telescope in Haleakala, Hawaii. We will present a summary of the overall results, as well as the latest news from 2013 campaigns. We will discuss the impact promoted by the past events, such as how the interest in astronomy changed before and after the campaigns, and it has helped the students to choose their future careers. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014acm..conf...67B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014acm..conf...67B">Infrared near-Earth-object survey modeling for observatories interior to the Earth's orbit</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Buie, M. 2014-07-01 The search for and dynamical characterization of the near-Earth population of objects (NEOs) has been a busy topic for surveys for many years. Most of the work thus far has been from ground-based optical surveys such as the Catalina Sky Survey and LINEAR. These surveys have essentially reached a complete inventory of objects down to 1 km diameter and have shown that the known objects do not pose any significant impact threat. Smaller objects are correspondingly smaller threats but there are more of them and fewer of them have so far been discovered. The next generation of surveys is looking to extend their reach down to much smaller sizes. From an impact risk perspective, those objects as small as 30--40 m are still of interest (similar in size to the Tunguska bolide). Smaller objects than this are largely of interest from a space resource or in-situ analysis efforts. A recent mission concept promoted by the B612 Foundation and Ball Aerospace calls for an infrared survey telescope in a Venus-like orbit, known as the Sentinel Mission. This wide-field facility has been designed to complete the inventory down to a 140 m diameter while also providing substantial constraints on the NEO population down to a Tunguska-sized object. I have been working to develop a suite of tools to provide survey modeling for this class of survey telescope. The purpose of the tool is to uncover hidden complexities that govern mission design and operation while also working to quantitatively understand the orbit quality provided on its catalog of objects without additional followup assets. The baseline mission design calls for a 6.5 year survey lifetime. This survey model is a statistically based tool for establishing completeness as a function of object size and survey duration. Effects modeled include the ability to adjust the field-of-regard (includes all pointing restrictions), field-of-view, focal plane array fill factor, and the observatory orbit. Consequences tracked include time-tagged detection times from which orbit quality can be derived and efficiency by dynamical class. The dominant noise term in the simulations comes from the noise in the background flux caused by thermal emission from zodiacal dust. The model used is sufficient for the study of reasonably low-inclination spacecraft orbits such as are being considered. Results to date are based on the 2002 Bottke NEA orbit-distribution model. The system can work with any orbit-distribution model and with any size-frequency distribution. This tool also serves to quantify the amount of data that will also be collected on main-belt objects by simply testing against the known catalog of bodies. The orbit quality work clearly shows the benefit of a self-followup survey such as Sentinel. Most objects discovered will be seen in multiple observing epochs and the resulting orbits will preclude losing track of them for decades to come (or longer). All of the ephemeris calculations, including investigation of orbit determination quality, are done with the OpenOrb software package. The presentation for this meeting will be based on results of modeling the Sentinel Mission and other similar variants. The focus will be on evaluating the survey completion for different dynamical classes as well as for different sized objects. Within the fidelity of such statistically-based models, the planned Sentinel observatory is well capable of a huge step forward in the efforts to build a complete catalog of all objects that could pose future harm to planet Earth. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4851605H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4851605H">Discovery of Spin-Rate-Dependent Asteroid Thermal Inertia</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Harris, Alan; Drube, Line 2016-10-01 Knowledge of the surface thermal inertia of an asteroid can provide insight into surface structure: porous material has a lower thermal inertia than rock. Using WISE/NEOWISE data and our new asteroid thermal-inertia estimator we show that the thermal inertia of main-belt asteroids (MBAs) appears to increase with spin period. Similar behavior is found in the case of thermophysically-modeled thermal inertia values of near-Earth objects (NEOs). We interpret our results in terms of rapidly increasing material density and thermal conductivity with depth, and provide evidence that thermal inertia increases by factors of 10 (MBAs) to 20 (NEOs) within a depth of just 10 cm. On the basis of a picture of depth-dependent thermal inertia our results suggest that, in general, thermal inertia values representative of solid rock are reached some tens of centimeters to meters below the surface in the case of MBAs (the median diameter in our dataset = 24 km). In the case of the much smaller (km-sized) NEOs a thinner porous surface layer is indicated, with large pieces of solid rock possibly existing just a meter or less below the surface. These conclusions are consistent with our understanding from in-situ measurements of the surfaces of the Moon, and a few asteroids, and suggest a very general picture of rapidly changing material properties in the topmost regolith layers of asteroids. Our results have important implications for calculations of the Yarkovsky effect, including its perturbation of the orbits of potentially hazardous objects and those of asteroid family members after the break-up event. Evidence of a rapid increase of thermal inertia with depth is also an important result for studies of the ejecta-enhanced momentum transfer of impacting vehicles ("kinetic impactors") in planetary defense. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014acm..conf..239J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014acm..conf..239J">Minimoons & drifters</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Jedicke, R.; Bolin, B.; Chyba, M.; Fedorets, G.; Granvik, M.; Patterson, G.; Vaubaillon, J. 2014-07-01 We will present an overview of our recent work on understanding the population of natural objects that are temporarily captured in the Earth-Moon system. We use the term 'minimoon' to refer to objects that i) have negative total energy (kinetic+potential) relative to the Earth-Moon barycenter that ii) make at least one full revolution around the barycenter in a co-rotating frame relative to the Earth-Sun axis iii) while they are within 3 Earth Hill-sphere radii. There has been one confirmed minimoon, the 2-3 meter diameter object designated 2006 RH_{120} that was discovered by the Catalina Sky Survey [1]. That object's size, capture duration, geocentric trajectory, and pre-and post-capture heliocentric orbits are in perfect agreement with the minimoon model proposed by Granvik et al. (2012) [2]. We expect that there are one or two 1 to 2 meter diameter minimoons in the steady state population at any time and about a dozen larger than 50 cm diameter. Minimoons have an average lifetime of about 9 months. 'Drifters' are like minimoons except that they do not fulfill the requirement of making at least one revolution in the Earth-Moon system. The population of drifters is about 10× the minimoon population so that the largest drifter in the steady state is about 5-10 meters in diameter and there are perhaps ten of about 1 meter diameter at any time. The combined population of minimoons and drifters, henceforth 'cis-lunar objects' (CLO), provide a formerly unrecognized opportunity for scientific exploration and testing concepts for in-situ resource utilization [3]. They could provide large samples of main-belt asteroids that are unaffected by passage through Earth's atmosphere or weathering on the ground, with the added convenience of already being gravitationally bound in the Earth-Moon system. The CLOs provide interesting challenges for rendezvous missions because of their limited lifetime and non-elliptical trajectories while they are bound objects [4]. The problem is that detecting the CLOs is difficult -- they are small, captured for only limited time periods, and their apparent rates of motion are more like artificial satellites than the more distant NEOs [5]. New technology may enable the detection of a small number of CLOs from the ground in the next few years [5,6] but the only way to discover a reliable stream of these interesting objects is from a space-based platform. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/992197','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/992197">Challenges of deflecting an asteroid or cometary nucleus with a nuclear burst</a> <a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Bradley, Paul A; Plesko, Cathy S; Clement, Ryan R C 2009-01-01 There are many natural disasters that humanity has to deal with over time. These include earthquakes, tsunami, hurricanes, floods, asteroid strikes, and so on. Many of these disasters occur slowly enough that some advance warning of which areas will be affected is possible. However, in almost all cases, the response is to evacuate the area to be affected and deal with the damage later. The evacuations for hurricanes Katrina and Rita on the US Gulf Coast in 2005 demonstrated the chaos that can result. In contrast with other natural disasters. it is likely that an asteroid or cometary nucleus onmore » a collision course with Earth is likely to be detected with enough warning time to possibly deflect it away from the collision course. Thanks to near-Earth object (NEO) surveys, people are working towards a goal of cataloging at least 90% of all near-Earth objects with diameters larger than {approx}140 meters in the next decade. The question is how to mitigate the threat from an asteroid or cometary nucleus found to be on a collision course. We briefly review some possible methods, describing their good and bad points, and then embark on a more detailed description of using a nuclear munition in standoff mode to deflect an asteroid or cometary nucleus before it can hit Earth.« less </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MNRAS.467.1016A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MNRAS.467.1016A">The Rafita asteroid family</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Aljbaae, S.; Carruba, V.; Masiero, J. R.; Domingos, R. C.; Huaman, M. 2017-05-01 The Rafita asteroid family is an S-type group located in the middle main belt, on the right-hand side of the 3J:-1A mean-motion resonance. The proximity of this resonance to the family left-hand side in the semimajor axis caused many former family members to be lost. As a consequence, the family shape in the (a, 1/D) domain is quite asymmetrical, with a preponderance of objects on the right-hand side of the distribution. The Rafita family is also characterized by a leptokurtic distribution in inclination, which allows the use of methods of family age estimation recently introduced for other leptokurtic families such as Astrid, Hansa, Gallia and Barcelona. In this work, we propose a new method based on the behaviour of an asymmetry coefficient function of the distribution in the (a, 1/D) plane to date incomplete asteroid families such as Rafita. By monitoring the time behaviour of this coefficient for asteroids simulating the initial conditions at the time of the family formation, we were able to estimate that the Rafita family should have an age of 490 ± 200 Myr, in good agreement with results from independent methods such as Monte Carlo simulations of Yarkovsky and YORP dynamical induced evolution and the time behaviour of the kurtosis of the sin (I) distribution. Asteroids from the Rafita family can reach orbits similar to 8 per cent of the currently known near-Earth objects. During the final 10 Myr of the simulation, ≃1 per cent of the simulated objects are present in NEO space, and thus would be comparable to objects in the present-day NEO population. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018A%26A...612A..76B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018A%26A...612A..76B">NELIOTA: First temperature measurement of lunar impact flashes</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Bonanos, A. Z.; Avdellidou, C.; Liakos, A.; Xilouris, E. M.; Dapergolas, A.; Koschny, D.; Bellas-Velidis, I.; Boumis, P.; Charmandaris, V.; Fytsilis, A.; Maroussis, A. 2018-04-01 We report the first scientific results from the NELIOTA (NEO Lunar Impacts and Optical TrAnsients) project, which has recently begun lunar monitoring observations with the 1.2-m Kryoneri telescope. NELIOTA aims to detect faint impact flashes produced by near-Earth meteoroids and asteroids and thereby help constrain the size-frequency distribution of near-Earth objects in the decimeter to meter range. The NELIOTA setup, consisting of two fast-frame cameras observing simultaneously in the R and I bands, enables - for the first time - direct analytical calculation of the flash temperatures. We present the first ten flashes detected, for which we find temperatures in the range 1600 to 3100 K, in agreement with theoretical values. Two of these flashes were detected on multiple frames in both filters and therefore yield the first measurements of the temperature drop for lunar flashes. In addition, we compute the impactor masses, which range between 100 g and 50 kg. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170009081','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170009081">Maturation of the Asteroid Threat Assessment Project</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Arnold, J. O..; Burkhard, C. D. 2017-01-01 As described at IPPW 12 [1], NASA initiated a new research activity focused on Planetary Defense (PD) on October 1, 2014. The overarching function of the Asteroid Threat Assessment Project (ATAP) is to provide capabilities to assess impact damage of any Near-Earth Object (NEO) that could inflict on the Earth. The activity includes four interrelated efforts: Initial Conditions (at the atmospheric entry interface); Entry Modeling (energy deposition in the atmosphere); Hazards (on the surface including winds, over pressures, thermal exposures, craters, tsunami and earthquakes) and Risk (physics-based). This paper outlines progress by ATAP and highlights achievements that are complimentary to activities of interest to the International Planetary Probe community. The ATAPs work is sponsored by NASAs Planetary Defense Coordination Office (PDCO), a part of the agency's Science Mission Directorate [1] Arnold, J. O., et. al., Overview of a New NASA Activity Focused on Planetary Defense, IPPW 12 Cologne Germany, June 15-19. 2015. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E2091Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E2091Y">Planetary Protection Progress of Hayabusa2 and Its Piggyback PROCYON: Launch, Earth Swingby and Outbound Cruising Phases</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Yano, Hajime; Yoshikawa, Makoto; Sarli, Bruno; Ozaki, Naoya; Funase, Ryu; Tsuda, Yuichi; Chujo, Toshihiro; Ariu, Kaito 2016-07-01 Hayabusa-2 is Japan's second asteroid sample return mission which was successfully launched into the planned Earth departure trajectory with the H-IIA rocket on December 3rd, 2014, together with a group of its interplanetary piggyback micro- spacecraft, including the PROCYON(Proximate Object Close flYby with Optical Navigation)spacecraft, the world's first 50 kg-class deep space micro-spacecraft developed by the University of Tokyo and the Japan Aerospace Exploration Agency. The Hayabusa-2 spacecraft will go to Rug, a C-type NEO, and attempt surface investigations with daughter rovers (MINERVA-II series and MASCOT), artificial impact cratering experiment (SCI) and both surface and sub-surface sampling (Sampler) in 2018-2019 and plans to return to the Earth in December 2020. The PROCYON mission objective was to demonstrate a micro-spacecraft bus technology for deep space exploration and proximity flyby to asteroids performing optical measurements. Both of the above missions were fully evaluated by the COSPAR Planetary Protection Panel at the dedicated COSPAR colloquium and scientific assembly in 2014 and the COSPAR PPP has endorsed the Category-2 for their outbound trajectories and the non-restricted Earth return for the inbound trajectory of Hayabusa-2. As a part of the fulfillments of the Category-2 classification, both spacecraft must be compliant with the COSPAR PPP requirements of non-impact probability to Mars since they would have enough energy to reach and beyond the orbit of Mars, due to the Earth swing-by and ion engine operations for their outbound cruising. As for the Hayabusa-2 spacecraft, it successfully performed its Earth gravity assist in December 2015, resulting on accurate orbit determination for the post-swing-by orbit to be ready to restart the ion engine operation. Thus the non-impact probability to Mars did not change from the estimate given by Chujo, et al. (2015). As for the PROCYON spacecraft after the completion of the bus system demonstration, it started deep space maneuver using the ion engines so that the spacecraft would be injected into an asteroid flyby trajectory via the Earth swing-by scheduled in December 2015. However, malfunction of the PROCYON high voltage system in the thruster occurred in March 2015, and the operation of the ion thruster stopped after 223 hours of successful continuous operation. Due to this anomaly, PROCYON gave up reaching its final destination (NEO "2000 DP107"); thus it now can be said that the spacecraft will never impact on Mars. In this paper, we summarize the mission status of the both projects in terms of the COSPAR PPP perspectives. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DPS....4730804M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DPS....4730804M">Dormant Comets in the Near-Earth Asteroid Population</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Mommert, Michael; Harris, Alan W.; Mueller, Michael; Hora, Joseph L.; Trilling, David E.; Knight, Matthew; Bottke, William F.; Thomas, Cristina; Delbo', Marco; Emery, Josh P.; Fazio, Giovanni; Smith, Howard A. 2015-11-01 The population of near-Earth objects comprises active comets and asteroids, covering a wide range of dynamical parameters and physical properties. Dormant (or extinct) comets, masquerading as asteroids, have long been suspected of supplementing the near-Earth asteroid (NEA) population. We present a search for asteroidal objects of cometary origin based on dynamical and physical considerations. Our study is based on albedos derived within the ExploreNEOs program and is extended by adding data from NEOWISE and the Akari asteroid catalog. We use a statistical approach to identify asteroids on orbits that resemble those of short-period near-Earth comets using the Tisserand parameter with respect to Jupiter, the aphelion distance, and the minimum orbital intersection distance with respect to Jupiter. We identify a total of 23 near-Earth asteroids from our sample that are likely to be dormant short-period near-Earth comets and, based on a de-biasing procedure applied to the cryogenic NEOWISE survey, estimate both magnitude-limited and size-limited fractions of the NEA population that are dormant short-period comets. We find that 0.3-3.3% of the NEA population with H <= 21, and 9(+2/-5)% of the population with diameters d >= 1 km, are dormant short-period near-Earth comets. We also present an observation program that utilizes the 1.8m Vatican Advanced Technology Telescope (VATT) on Mt. Graham, AZ, to identify dormant comet candidates and search for activity in these objects. Our targets are NEAs on comet-like orbits, based on the dynamical criteria derived in the above study, that are accessible with the VATT (V <= 22). We identify dormant comets based on their optical spectral slope, represented by V-R color measurements, as albedo measurements for most of these objects are not available. For each target we measure and monitor its V magnitude in order to reveal activity outbreaks. We also search for extended emission around our targets using deep imaging and a point-spread-function subtraction technique that allows us to obtain an upper limit on the dust production rate in each target. We present preliminary results from this program. This work is supported in part by funding from the Spitzer Science Center. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active">14</li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active">15</li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=Freedom&pg=7&id=EJ1029687','ERIC'); return false;" href="https://eric.ed.gov/?q=Freedom&pg=7&id=EJ1029687">Free to Manage? A Neo-Liberal Defence of Academic Freedom in British Higher Education</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Miller, Brian 2014-01-01 Much of the rhetoric opposing managerialism in higher education can be ascribed to philosophical and political objections to the neo-liberal ideology which is alleged to underlie the phenomenon. This paper approaches managerialism from a different direction, addressing it within a neo-liberal framework. The paper argues that there is no intrinsic… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4840506L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4840506L">The LCOGT NEO Follow-up Network</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Lister, Tim; Greenstreet, Sarah; Gomez, Edward; Christensen, Eric J.; Larson, Stephen M. 2016-10-01 The LCOGT NEO Follow-up Network is using the telescopes of the Las Cumbres Observatory Global Telescope Network (LCOGT) and a web-based target selection, scheduling and data reduction system to confirm NEO candidates and characterize radar-targeted known NEOs. Starting in July 2014, the LCOGT NEO Follow-up Network has observed over 3,500 targets and reported more than 16,000 astrometric and photometric measurements to the Minor Planet Center (MPC).The LCOGT NEO Follow-up Network's main aims are to perform confirming follow-up of the large number of NEO candidates and to perform characterization measurements of radar targets to obtain light curves and rotation rates. The NEO candidates come from the NEO surveys such as Catalina, PanSTARRS, ATLAS, NEOWISE and others. In particular, we are targeting objects in the Southern Hemisphere, where the LCOGT NEO Follow-up Network is the largest resource for NEO observations.LCOGT has completed the first phase of the deployment with the installation and commissioning of the nine 1-meter telescopes at McDonald Observatory (Texas), Cerro Tololo (Chile), SAAO (South Africa) and Siding Spring Observatory (Australia). The telescope network has been fully operational since 2014 May, and observations are being executed remotely and robotically. Future expansion to a site at Ali Observatory, Tibet is planned for 2017-2018.We have developed web-based software called NEOexchange which automatically downloads and aggregates NEO candidates from the Minor Planet Center's NEO Confirmation Page, the Arecibo and Goldstone radar target lists and the NASA ARM list. NEOexchange allows the planning and scheduling of observations on the LCOGT Telescope Network and the tracking of the resulting blocks and generated data. We have recently extended the NEOexchange software to include automated data reduction to re-compute the astrometric solution, determine the photometric zeropoint and find moving objects and present these results to the user via the website.We will present results from the LCOGT NEO Follow-up Network and from the development of the NEOexchange software which is used to schedule, analyze and report observations taken with the LCOGT Network. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010019448&hterms=hplc&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dhplc','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010019448&hterms=hplc&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dhplc">Amino Acid Chemistry as a Link Between Small Solar System Bodies and Carbonaceous Chondrites</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Glavin, Daniel P.; Ehrenfreund, Pascale; Botta, Oliver; Cooper, George; Bada, Jeffrey L. 2000-01-01 Establishing chemical links between meteorites and small solar system bodies, such as comets and asteroids, provides a tool for investigating the processes that occurred during the formation of the solar system. Carbonaceous meteorites are of particular interest, since they may have seeded the early Earth with a variety of prebiotic organic compounds including amino acids, purines and pyrimidines, which are thought to be necessary for the origin of life. Here we report the results of high-performance liquid chromatography (HPLC) based amino acid analyses of the acid-hydrolyzed hot water extracts from pristine interior pieces of the CI carbonaceous chondrites Orgueil and Ivuna and the CM meteorites Murchison and Murray. We found that the CI meteorites Orgueil and Ivuna contained high abundances of beta-alanine and glycine, while only traces of other amino acids like alanine, alpha-amino-n-butryic acid (ABA) and alpha-aminoisobutyric acid (AIB) were detected in these meteorites. Carbon isotopic measurements of beta-alanine and glycine in Orgueil by gas chromatography combustion-isotope ratio mass spectrometry clearly indicate an extraterrestrial origin of these amino acids. The amino acid composition of Orgueil and Ivuna was strikingly different from the CM chondrites Murchison and Murray. The most notable difference was the high relative abundance of B-alanine in Orgueil and Ivuna compared to Murchison and Murray. Furthermore, AIB, which is one of the most abundant amino acids found in Murchison and Murray, was present in only trace amounts in Orgueil and Ivuna. Our amino acid data strongly suggest that the CI meteorites Orgueil and Ivuna came from a different type of parent body than the CM meteorites Murchison and Murray, possibly from an extinct comet. It is generally thought that carbonaceous meteorites are fragments of larger asteroidal bodies delivered via near Earth objects (NEO). Orbital and dynamic studies suggest that both fragments of main belt asteroids and comets replenish the NEO population, therefore extinct comets may contribute up to half of all NEO's. A comparison of an amino acid analysis of a returned NEO sample to CI and CM carbonaceous chondrites would help establish a link between small solar system bodies and meteorites. Based on our amino acid measurements of CI and CM chondrites, amino acid chemistry can be included as an additional set of criteria to constrain the nature of meteorite parent bodies. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100027329','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100027329">A Flexible Path for Human and Robotic Space Exploration</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Korsmeyer, David J.; Landis, Robert; Merrill, Raymond Gabriel; Mazanek, Daniel D.; Falck, Robert D.; Adams, Robert B. 2010-01-01 During the summer of 2009, a flexible path scenario for human and robotic space exploration was developed that enables frequent, measured, and publicly notable human exploration of space beyond low-Earth orbit (LEO). The formulation of this scenario was in support of the Exploration Beyond LEO subcommittee of the Review of U.S. Human Space Flight Plans Committee that was commissioned by President Obama. Exploration mission sequences that allow humans to visit a wide number of inner solar system destinations were investigated. The scope of destinations included the Earth-Moon and Earth-Sun Lagrange points, near-Earth objects (NEOs), the Moon, and Mars and its moons. The missions examined assumed the use of Constellation Program elements along with existing launch vehicles and proposed augmentations. Additionally, robotic missions were envisioned as complements to human exploration through precursor missions, as crew emplaced scientific investigations, and as sample gathering assistants to the human crews. The focus of the flexible path approach was to gain ever-increasing operational experience through human exploration missions ranging from a few weeks to several years in duration, beginning in deep space beyond LEO and evolving to landings on the Moon and eventually Mars. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120003306','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120003306">Managing Science Operations during Planetary Surface Operations at Long Light Delay-Time Targets: The 2011 Desert RATS Test</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Eppler, D. B. 2012-01-01 Desert Research and Technology Studies (Desert RATS) is a multi-year series of hardware and operations tests carried out annually in the high desert of Arizona in the San Francisco Volcanic Field. Conducted since 1997, these activities are designed to exercise planetary surface hardware and operations in conditions where multi-day tests are achievable. Desert RATS 2011 Science Operations Test simulated the management of crewed science operations at targets that were beyond the light delay time experienced during Low-Earth Orbit (LEO) and lunar surface missions, such as a mission to a Near-Earth Object (NEO) or the martian surface. Operations at targets at these distances are likely to be the norm as humans move out of the Earth-Moon system. Operating at these distances places significant challenges on mission operations, as the imposed light-delay time makes normal, two-way conversations extremely inefficient. Consequently, the operations approach for space missions that has been exercised during the first half-century of human space operations is no longer viable, and new approaches must be devised. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017DPS....4911010L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017DPS....4911010L">The LCO Follow-up and Characterization Network and AgentNEO Citizen Science Project</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Lister, Tim; Greenstreet, Sarah; Gomez, Edward; Christensen, Eric J.; Larson, Stephen M. 2017-10-01 The LCO NEO Follow-up Network is using the telescopes of the Las Cumbres Observatory (LCO) and a web-based target selection, scheduling and data reduction system to confirm NEO candidates and characterize radar-targeted known NEOs. Starting in July 2014, the LCO NEO Follow-up Network has observed over 4,500 targets and reported more than 25,000 astrometric and photometric measurements to the Minor Planet Center.The LCO NEO Follow-up Network's main aims are to perform confirming follow-up of the large number of NEO candidates and to perform characterization measurements of radar targets to obtain light curves and rotation rates. The NEO candidates come from the NEO surveys such as Catalina, PanSTARRS, ATLAS, NEOWISE and others. In particular, we are targeting objects in the Southern Hemisphere, where the LCO NEO Follow-up Network is the largest resource for NEO observations.The first phase of the LCO Network comprises nine 1-meter and seven 0.4-meter telescopes at site at McDonald Observatory (Texas), Cerro Tololo (Chile), SAAO (South Africa) and Siding Spring Observatory (Australia). The network has been fully operational since 2014 May, and observations are being executed remotely and robotically. Additional 0.4-meter telescopes will be deployed in 2017 and 2x1-meter telescopes for a site at Ali Observatory, Tibet are planned for 2018-2019.We have developed web-based software called NEOexchange which automatically downloads and aggregates NEO candidates from the Minor Planet Center's NEO Confirmation Page, the Arecibo and Goldstone radar target lists and the NASA lists. NEOexchange allows the planning and scheduling of observations on the LCO Telescope Network and the tracking of the resulting blocks and generated data. We have extended the NEOexchange software to include automated scheduling and moving object detection, with the results presented to the user via the website.We will present results from the LCO NEO Follow-up Network and from the development of the NEOexchange software which is used to schedule, analyze and report observations taken with the LCO Network. In addition, we describe a Citizen Science project, AgentNEO, which uses LCO data to allow the public to find and learn about asteroids. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050186573','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050186573">Orbit Modification of Earth-Crossing Asteroids/Comets Using Rendezvous Spacecraft and Laser Ablation</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Park, Sang-Young; Mazanek, Daniel D. 2005-01-01 This report describes the approach and results of an end-to-end simulation to deflect a long-period comet (LPC) by using a rapid rendezvous spacecraft and laser ablation system. The laser energy required for providing sufficient deflection DELTA V and an analysis of possible intercept/rendezvous spacecraft trajectories are studied in this analysis. These problems minimize a weighted sum of the flight time and required propellant by using an advanced propulsion system. The optimal thrust-vector history and propellant mass to use are found in order to transfer a spacecraft from the Earth to a targeted celestial object. One goal of this analysis is to formulate an optimization problem for intercept/rendezvous spacecraft trajectories. One approach to alter the trajectory of the object in a highly controlled manner is to use pulsed laser ablative propulsion. A sufficiently intense laser pulse ablates the surface of a near-Earth object (NEO) by causing plasma blowoff. The momentum change from a single laser pulse is very small. However, the cumulative effect is very effective because the laser can interact with the object over long periods of time. The laser ablation technique can overcome the mass penalties associated with other nondisruptive approaches because no propellant is required to generate the DELTA V (the material of the celestial object is the propellant source). Additionally, laser ablation is effective against a wide range of surface materials and does not require any landing or physical attachment to the object. For diverting distant asteroids and comets, the power and optical requirements of a laser ablation system on or near the Earth may be too extreme to contemplate in the next few decades. A hybrid solution would be for a spacecraft to carry a laser as a payload to a particular celestial body. The spacecraft would require an advanced propulsion system capable of rapid rendezvous with the object and an extremely powerful electrical generator, which is likely needed for the propulsion system as well. The spacecraft would station-keep with the object at a small standoff distance while the laser ablation is performed. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EPSC....8..773T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EPSC....8..773T">Are 2P/Encke, the Taurid complex NEOs and CM chondrites related?</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Tubiana, C.; Snodgrass, C.; Michelsen, R.; Haack, H.; Fitzsimmons, A.; Williams, I.; Boehnhardt, H. 2013-09-01 Comet 2P/Encke is a short-period comet that was discovered in 1786 and has been extensively observed and studied for more than 200 years. It has an orbital period of 3.3 years and its orbit is dynamically decoupled from Jupiter's control due to gravitational interaction with terrestrial planets [6]. It is the only comet known on such an orbit, making it unique. Capture from the outer solar system onto its current orbit is very unlikely and even a continuous smooth dynamical evolution has a low probability as this requires a continuous period when it is dormant in order to avoid the volatiles from the nucleus becoming exhausted and making the current observed activity impossible. An origin in the asteroid belt is a possibility especially in view of the recently discovered main belt comets. The nucleus of 2P/Encke is dark (geometric albedo of 0.047 ± 0.023 [3]), has an effective radius of 2.4 ± 0.3 km [3] and it has polarimetric properties that are unique compared to other measured types of solar system objects, such as asteroids, TNOs, cometary dust, Centaurs [2]. The colors of 2P/Encke's nucleus are typical for comets, but no spectra of the nucleus in the visible wavelength range exist so far. The Taurid meteoroid stream has long been linked with 2P/Encke, but the activity of the comet is not strong enough to explain the number of observed meteors. It has been suggested that the meteoroid stream was caused by the break up of a larger parent body, which left comet 2P/Encke and other various small bodies along with a stream of dust. Various small near-Earth objects (NEOs) have been discovered with orbits that can be linked with 2P/Encke and the Taurid meteoroid stream [1]. Though many of the associations are spurious due to the low inclination of 2P/Encke's orbit, many NEO's have evolved in a similar way to 2P/Encke overa period of 5000 years [8] suggesting some relationship. In addition to dynamical properties, common taxonomic properties can also provide an indication of a common origin for small bodies in the solar system. Taxonomic properties are poorly known for cometary nuclei and only few comets have measurements in the visible wavelength range. The existing spectra of bare nuclei are generally featureless and display different reddening slopes. Given the poor S/N ratio that is usually obtained in observations, more subtle features, such as ones from hydrated minerals, are beyond the detection limit in most cases. If the Taurid complex NEOs are fragments of the same body as 2P/Encke, we expect them to have the same spectral properties as the comet nucleus. Furthermore, it would be reasonable to expect that these NEOs could show cometary activity. Maribo is a type CM carbonaceous chondrite that fell in Denmark on 17 January 2009 [5]. The preatmospheric orbit of the object places it in the middle of the Taurid meteor stream [4], which raises the intriguing possibility that comet 2P/Encke could be the parent body of CM chondrites, meaning that these meteorites are potentially samples of cometary material we can study in the laboratory. CM chondrites show signs of extensive aqueous alteration, which suggest that the parent body was an icy body that was at least partially molten at some point. It is therefore possible that the parent body of the CM chondrites is a comet [7]. In order to investigate whether a relationship between comet 2P/Encke, the Taurid complex associated NEOs and CM chondrites exists, spectroscopic studies of these objects were performed. Here we present ground-based observations, in the visible wavelength range, of 2P/Encke and 12 candidate Taurid NEOs obtained on 2 August 2011 at the ESO-VLT in Chile, using the FORS2 instrument. We obtained the first optical spectrum of the inactive nucleus of comet 2P/Encke and optical spectra of the selected candidate Taurid NEOs. In addition we obtained deep images in the R filter of each NEO to search for activity and of 2P/Encke to confirm that the comet was not active at the time of the observation. Preliminary analysis shows that 2P/Encke has a starlike profile, confirming that no cometary activity was present at the time of the observation. Its spectrum is flat and does not show any obvious absorption or mission feature in the wavelength range 400 - 950 nm. The spectra of the 12 Taurid NEOs are featureless as well and two of them show moderate reddening. Using deep R-filter images we will investigate the presence of weak activity around the asteroids. We will look for similarities between the spectrum of 2P/Encke and the ones of the selected NEOs to test the link between the comet and the Taurid complex associated NEOs. Moreover, a comparison between chondritic meteorite spectra and that of 2P/Encke will provide information about the possible link between 2P/Encke and CM chondrites. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002Icar..159..423C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002Icar..159..423C">Quantifying the Risk Posed by Potential Earth Impacts</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Chesley, Steven R.; Chodas, Paul W.; Milani, Andrea; Valsecchi, Giovanni B.; Yeomans, Donald K. 2002-10-01 Predictions of future potential Earth impacts by near-Earth objects (NEOs) have become commonplace in recent years, and the rate of these detections is likely to accelerate as asteroid survey efforts continue to mature. In order to conveniently compare and categorize the numerous potential impact solutions being discovered we propose a new hazard scale that will describe the risk posed by a particular potential impact in both absolute and relative terms. To this end, we measure each event in two ways, first without any consideration of the event's time proximity or its significance relative to the so-called background threat, and then in the context of the expected risk from other objects over the intervening years until the impact. This approach is designed principally to facilitate communication among astronomers, and it is not intended for public communication of impact risks. The scale characterizes impacts across all impact energies, probabilities and dates, and it is useful, in particular, when dealing with those cases which fall below the threshold of public interest. The scale also reflects the urgency of the situation in a natural way and thus can guide specialists in assessing the computational and observational effort appropriate for a given situation. In this paper we describe the metrics introduced, and we give numerous examples of their application. This enables us to establish in rough terms the levels at which events become interesting to various parties. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110006982','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110006982">Deep Space Habitat Team: HEFT Phase 2 Effects</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Toups, Larry D.; Smitherman, David; Shyface, Hilary; Simon, Matt; Bobkill, Marianne; Komar, D. R.; Guirgis, Peggy; Bagdigian, Bob; Spexarth, Gary 2011-01-01 HEFT was a NASA-wide team that performed analyses of architectures for human exploration beyond LEO, evaluating technical, programmatic, and budgetary issues to support decisions at the highest level of the agency in HSF planning. HEFT Phase I (April - September, 2010) and Phase II (September - December, 2010) examined a broad set of Human Exploration of Near Earth Objects (NEOs) Design Reference Missions (DRMs), evaluating such factors as elements, performance, technologies, schedule, and cost. At end of HEFT Phase 1, an architecture concept known as DRM 4a represented the best available option for a full capability NEO mission. Within DRM4a, the habitation system was provided by Deep Space Habitat (DSH), Multi-Mission Space Exploration Vehicle (MMSEV), and Crew Transfer Vehicle (CTV) pressurized elements. HEFT Phase 2 extended DRM4a, resulting in DRM4b. Scrubbed element-level functionality assumptions and mission Concepts of Operations. Habitation Team developed more detailed concepts of the DSH and the DSH/MMSEV/CTV Conops, including functionality and accommodations, mass & volume estimates, technology requirements, and DDT&E costs. DRM 5 represented an effort to reduce cost by scaling back on technologies and eliminating the need for the development of an MMSEV. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DPS....4720203R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DPS....4720203R">Hazardous Asteroids: Cloaking STEM Skills Training within an Attention-Grabbing Science/Math Course</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Ryan, Eileen V.; Ryan, William H. 2015-11-01 A graduate-level course was designed and taught during the summer months from 2009 - 2015 in order to contribute to the training and professional development of K-12 teachers residing in the Southwest. The teachers were seeking Master’s degrees via the New Mexico Institute of Mining and Technology’s (NMT’s) Masters of Science Teaching (MST) program, and the course satisfied a science or math requirement. The MST program provides opportunities for in-service teachers to enhance their content backgrounds in science, mathematics, engineering, and technology (SMET). The ultimate goal is to assist teachers in gaining knowledge that has direct application in the classroom.The engaging topic area of near-Earth object (NEO) characterization studies was used to create a fun and exciting framework for mastering basic skills and concepts in physics and astronomy. The objective was to offer a class that had the appropriate science rigor (with an emphasis on mathematics) within a non-threatening format. The course, entitled “Hazardous Asteroids”, incorporates a basic planetary physics curriculum, with challenging laboratories that include a heavy emphasis on math and technology. Since the authors run a NASA-funded NEO research and follow-up program, also folded into the course is the use of the Magdalena Ridge Observatory’s 2.4-meter telescope so participants can take and reduce their own data on a near-Earth asteroid.In exit assessments, the participants have given the course excellent ratings for design and implementation, and the overall degree of satisfaction was high. This validates that a well-constructed (and rigorous) course can be effective in receptively reaching teachers in need of basic skills refreshment. Many of the teachers taking the course were employed in school districts serving at-risk or under-prepared students, and the course helped provide them with the confidence vital to developing new strategies for successful teaching. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018P%26SS..156....2L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018P%26SS..156....2L">Nanodust released in interplanetary collisions</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Lai, H. R.; Russell, C. T. 2018-07-01 The lifecycle of near-Earth objects (NEOs) involves a collisional cascade that produces ever smaller debris ending with nanoscale particles which are removed from the solar system by radiation pressure and electromagnetic effects. It has been proposed that the nanodust clouds released in collisions perturb the background interplanetary magnetic field and create the interplanetary field enhancements (IFEs). Assuming that this IFE formation scenario is actually operating, we calculate the interplanetary collision rate, estimate the total debris mass carried by nanodust, and compare the collision rate with the IFE rate. We find that to release the same amount of nanodust, the collision rate is comparable to the observed IFE rate. Besides quantitatively testing the association between the collisions evolving large objects and giant solar wind structures, such a study can be extended to ranges of smaller scales and to investigate the source of moderate and small solar wind perturbations. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11151965','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11151965">Assessing the U.S. presidents using the Revised NEO Personality Inventory.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Rubenzer, S J; Faschingbauer, T R; Ones, D S 2000-12-01 This article describes the use of objective psychological instruments, including the Revised NEO Personality Inventory (NEO PI-R), to assess the personalities of all 41 U.S. presidents to date. We briefly report our findings pertaining to the average profile of chief executives on the NEO PI-R and summarize data on two of our most illustrious presidents, Washington and Lincoln. We review a typology of presidents based on our data. Finally, we summarize the results of our investigation of the Big Five personality dimensions and facets that are related to presidential success (i.e., historical greatness). The project and findings are discussed in terms of the use of the NEO PI-R in psychohistorical research and assessment. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015HiA....16..488V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015HiA....16..488V">A space mission to detect imminent Earth impactors</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Valsecchi, G. B.; Perozzi, E.; Rossi, A. 2015-03-01 One of the goals of NEO surveys is to discover Earth impactors before they hit. How much warning time is desirable depends on the size of the impactors: for the larger ones more time is needed to mount effective mitigation measures. Initially, NEO surveys were aimed at large impactors, that can have significant global effects; however, their typical time scale is orders of magnitude larger than human lifetime. At the other extreme, monthly and annual events, liberating energies of the order of 1 to 10 kilotons, are immaterial as a threat to mankind, not justifying substantial expenditure on them. Intermediate events are of more concern: in the megatons range, timescales are of the order of centuries, and the damage can be substantial. A classical example is the Tunguska event, in which a body with a diameter of about 30 to 50 m liberated about 5 megatons in the atmosphere, devastating 2 000 square kilometers of Siberian forest. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E1037K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E1037K">Annual Occurrence of Meteorite-Dropping Fireballs</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Konovalova, Natalia; Jopek, Tadeusz J. 2016-07-01 The event of Chelyabinsk meteorite has brought about change the earlier opinion about limits of the sizes of potentially dangerous asteroidal fragments that crossed the Earth's orbit and irrupted in the Earth's atmosphere making the brightest fireball. The observations of the fireballs by fireball networks allows to get the more precise data on atmospheric trajectories and coordinates of predicted landing place of the meteorite. For the reason to search the periods of fireball activity is built the annual distribution of the numbers of meteorites with the known fall dates and of the meteorite-dropping fireballs versus the solar longitude. The resulting profile of the annual activity of meteorites and meteorite-dropping fireballs shows several periods of increased activity in the course of the year. The analysis of the atmospheric trajectories and physical properties of sporadic meteorite-dropping fireballs observed in Tajikistan by instrumental methods in the summer‒autumn periods of increased fireballs activity has been made. As a result the structural strength, the bulk density and terminal mass of the studied fireballs that can survive in the Earth atmosphere and became meteorites was obtained. From the photographic IAU MDC_2003 meteor database and published sources based on the orbit proximity as determined by D-criterion of Southworth and Hawkins the fireballs that could be the members of group of meteorite-dropping fireballs, was found. Among the near Earth's objects (NEOs) the searching for parent bodies for meteorite-dropping fireballs was made and the evolution of orbits of these objects in the past on a long interval of time was investigated. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120006503','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120006503">Environmental Controls and Life Support System Design for a Space Exploration Vehicle</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Stambaugh, Imelda C.; Rodriguez, Branelle; Vonau, Walt, Jr.; Borrego, Melissa 2012-01-01 Engineers at Johnson Space Center (JSC) are developing an Environmental Control and Life Support System (ECLSS) design for the Space Exploration Vehicle (SEV). The SEV will aid to expand the human exploration envelope for Geostationary Transfer Orbit (GEO), Near Earth Object (NEO), or planetary missions by using pressurized surface exploration vehicles. The SEV, formerly known as the Lunar Electric Rover (LER), will be an evolutionary design starting as a ground test prototype where technologies for various systems will be tested and evolve into a flight vehicle. This paper will discuss the current SEV ECLSS design, any work contributed toward the development of the ECLSS design, and the plan to advance the ECLSS design based on the SEV vehicle and system needs. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100037960','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100037960">Environmental Controls and Life Support System (ECLSS) Design for a Space Exploration Vehicle (SEV)</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Stambaugh, Imelda; Sankaran, Subra 2010-01-01 Engineers at Johnson Space Center (JSC) are developing an Environmental Control and Life Support System (ECLSS) design for the Space Exploration Vehicle (SEV). The SEV will aid to expand the human exploration envelope for Geostationary Transfer Orbit (GEO), Near Earth Object (NEO), or planetary missions by using pressurized surface exploration vehicles. The SEV, formerly known as the Lunar Electric Rover (LER), will be an evolutionary design starting as a ground test prototype where technologies for various systems will be tested and evolve into a flight vehicle. This paper will discuss the current SEV ECLSS design, any work contributed toward the development of the ECLSS design, and the plan to advance the ECLSS design based on the SEV vehicle and system needs. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120014091','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120014091">High-Performance Modeling and Simulation of Anchoring in Granular Media for NEO Applications</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Quadrelli, Marco B.; Jain, Abhinandan; Negrut, Dan; Mazhar, Hammad 2012-01-01 NASA is interested in designing a spacecraft capable of visiting a near-Earth object (NEO), performing experiments, and then returning safely. Certain periods of this mission would require the spacecraft to remain stationary relative to the NEO, in an environment characterized by very low gravity levels; such situations require an anchoring mechanism that is compact, easy to deploy, and upon mission completion, easy to remove. The design philosophy used in this task relies on the simulation capability of a high-performance multibody dynamics physics engine. On Earth, it is difficult to create low-gravity conditions, and testing in low-gravity environments, whether artificial or in space, can be costly and very difficult to achieve. Through simulation, the effect of gravity can be controlled with great accuracy, making it ideally suited to analyze the problem at hand. Using Chrono::Engine, a simulation pack age capable of utilizing massively parallel Graphic Processing Unit (GPU) hardware, several validation experiments were performed. Modeling of the regolith interaction has been carried out, after which the anchor penetration tests were performed and analyzed. The regolith was modeled by a granular medium composed of very large numbers of convex three-dimensional rigid bodies, subject to microgravity levels and interacting with each other with contact, friction, and cohesional forces. The multibody dynamics simulation approach used for simulating anchors penetrating a soil uses a differential variational inequality (DVI) methodology to solve the contact problem posed as a linear complementarity method (LCP). Implemented within a GPU processing environment, collision detection is greatly accelerated compared to traditional CPU (central processing unit)- based collision detection. Hence, systems of millions of particles interacting with complex dynamic systems can be efficiently analyzed, and design recommendations can be made in a much shorter time. The figure shows an example of this capability where the Brazil Nut problem is simulated: as the container full of granular material is vibrated, the large ball slowly moves upwards. This capability was expanded to account for anchors of different shapes and penetration velocities, interacting with granular soils. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120015091','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120015091">Solar Electric Propulsion Vehicle Demonstration to Support Future Space Exploration Missions</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Smith, Bryan K.; Nazario, Margaret L.; Cunningham, Cameron C. 2012-01-01 Human and robotic exploration beyond Low Earth Orbit (LEO) will require enabling capabilities that are efficient, affordable, and reliable. Solar Electric Propulsion (SEP) is highly advantageous because of its favorable in-space mass transfer efficiency compared to traditional chemical propulsion systems. The NASA studies have demonstrated that this advantage becomes highly significant as missions progress beyond Earth orbit. Recent studies of human exploration missions and architectures evaluated the capabilities needed to perform a variety of human exploration missions including missions to Near Earth Objects (NEOs). The studies demonstrated that SEP stages have potential to be the most cost effective solution to perform beyond LEO transfers of high mass cargoes for human missions. Recognizing that these missions require power levels more than 10X greater than current electric propulsion systems, NASA embarked upon a progressive pathway to identify critical technologies needed and a plan for an incremental demonstration mission. The NASA studies identified a 30kW class demonstration mission that can serve as a meaningful demonstration of the technologies, operational challenges, and provide the appropriate scaling and modularity required. This paper describes the planning options for a representative demonstration 30kW class SEP mission. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20150008926&hterms=adler&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dadler','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20150008926&hterms=adler&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dadler">Flexible-Path Human Exploration</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Sherwood, B.; Adler, M.; Alkalai, L.; Burdick, G.; Coulter, D.; Jordan, F.; Naderi, F.; Graham, L.; Landis, R.; Drake, B.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20150008926'); toggleEditAbsImage('author_20150008926_show'); toggleEditAbsImage('author_20150008926_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20150008926_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20150008926_hide"> 2010-01-01 In the fourth quarter of 2009 an in-house, multi-center NASA study team briefly examined "Flexible Path" concepts to begin understanding characteristics, content, and roles of potential missions consistent with the strategy proposed by the Augustine Committee. We present an overview of the study findings. Three illustrative human/robotic mission concepts not requiring planet surface operations are described: assembly of very large in-space telescopes in cis-lunar space; exploration of near Earth objects (NEOs); exploration of Mars' moon Phobos. For each, a representative mission is described, technology and science objectives are outlined, and a basic mission operations concept is quantified. A fourth type of mission, using the lunar surface as preparation for Mars, is also described. Each mission's "capability legacy" is summarized. All four illustrative missions could achieve NASA's stated human space exploration objectives and advance human space flight toward Mars surface exploration. Telescope assembly missions would require the fewest new system developments. NEO missions would offer a wide range of deep-space trip times between several months and two years. Phobos exploration would retire several Marsclass risks, leaving another large remainder set (associated with entry, descent, surface operations, and ascent) for retirement by subsequent missions. And extended lunar surface operations would build confidence for Mars surface missions by addressing a complementary set of risks. Six enabling developments (robotic precursors, ISS exploration testbed, heavy-lift launch, deep-space-capable crew capsule, deep-space habitat, and reusable in-space propulsion stage) would apply across multiple program sequence options, and thus could be started even without committing to a specific mission sequence now. Flexible Path appears to be a viable strategy, with meaningful and worthy mission content. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active">15</li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active">16</li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3930095','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3930095">Neo: an object model for handling electrophysiology data in multiple formats</a> <a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Garcia, Samuel; Guarino, Domenico; Jaillet, Florent; Jennings, Todd; Pröpper, Robert; Rautenberg, Philipp L.; Rodgers, Chris C.; Sobolev, Andrey; Wachtler, Thomas; Yger, Pierre; Davison, Andrew P. 2014-01-01 Neuroscientists use many different software tools to acquire, analyze and visualize electrophysiological signals. However, incompatible data models and file formats make it difficult to exchange data between these tools. This reduces scientific productivity, renders potentially useful analysis methods inaccessible and impedes collaboration between labs. A common representation of the core data would improve interoperability and facilitate data-sharing. To that end, we propose here a language-independent object model, named “Neo,” suitable for representing data acquired from electroencephalographic, intracellular, or extracellular recordings, or generated from simulations. As a concrete instantiation of this object model we have developed an open source implementation in the Python programming language. In addition to representing electrophysiology data in memory for the purposes of analysis and visualization, the Python implementation provides a set of input/output (IO) modules for reading/writing the data from/to a variety of commonly used file formats. Support is included for formats produced by most of the major manufacturers of electrophysiology recording equipment and also for more generic formats such as MATLAB. Data representation and data analysis are conceptually separate: it is easier to write robust analysis code if it is focused on analysis and relies on an underlying package to handle data representation. For that reason, and also to be as lightweight as possible, the Neo object model and the associated Python package are deliberately limited to representation of data, with no functions for data analysis or visualization. Software for neurophysiology data analysis and visualization built on top of Neo automatically gains the benefits of interoperability, easier data sharing and automatic format conversion; there is already a burgeoning ecosystem of such tools. We intend that Neo should become the standard basis for Python tools in neurophysiology. PMID:24600386 </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24600386','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24600386">Neo: an object model for handling electrophysiology data in multiple formats.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Garcia, Samuel; Guarino, Domenico; Jaillet, Florent; Jennings, Todd; Pröpper, Robert; Rautenberg, Philipp L; Rodgers, Chris C; Sobolev, Andrey; Wachtler, Thomas; Yger, Pierre; Davison, Andrew P 2014-01-01 Neuroscientists use many different software tools to acquire, analyze and visualize electrophysiological signals. However, incompatible data models and file formats make it difficult to exchange data between these tools. This reduces scientific productivity, renders potentially useful analysis methods inaccessible and impedes collaboration between labs. A common representation of the core data would improve interoperability and facilitate data-sharing. To that end, we propose here a language-independent object model, named "Neo," suitable for representing data acquired from electroencephalographic, intracellular, or extracellular recordings, or generated from simulations. As a concrete instantiation of this object model we have developed an open source implementation in the Python programming language. In addition to representing electrophysiology data in memory for the purposes of analysis and visualization, the Python implementation provides a set of input/output (IO) modules for reading/writing the data from/to a variety of commonly used file formats. Support is included for formats produced by most of the major manufacturers of electrophysiology recording equipment and also for more generic formats such as MATLAB. Data representation and data analysis are conceptually separate: it is easier to write robust analysis code if it is focused on analysis and relies on an underlying package to handle data representation. For that reason, and also to be as lightweight as possible, the Neo object model and the associated Python package are deliberately limited to representation of data, with no functions for data analysis or visualization. Software for neurophysiology data analysis and visualization built on top of Neo automatically gains the benefits of interoperability, easier data sharing and automatic format conversion; there is already a burgeoning ecosystem of such tools. We intend that Neo should become the standard basis for Python tools in neurophysiology. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011plde.confE...2B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011plde.confE...2B">Near-Earth asteroids orbits using Gaia and ground-based observations</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Bancelin, D.; Hestroffer, D.; Thuillot, W. 2011-05-01 Potentially Hazardous Asteroids (PHAs) are Near-Earth Asteroids caraterised by a Minimum Orbital Intersection Distance (MOID) with Earth less to 0.05 A.U and an absolute magnitude H<22. Those objects have sometimes a so significant close approach with Earth that they can be put on a chaotic orbit. This kind of orbit is very sensitive for exemple to the initial conditions, to the planetary theory used (for instance JPL's model versus IMCCE's model) or even to the numerical integrator used (Lie Series, Bulirsch-Stoer or Radau). New observations (optical, radar, flyby or satellite mission) can improve those orbits and reduce the uncertainties on the Keplerian elements.The Gaia mission is an astrometric mission that will be launched in 2012 and will observe a large number of Solar System Objects down to magnitude V≤20. During the 5-year mission, Gaia will continuously scan the sky with a specific strategy: objects will be observed from two lines of sight separated with a constant basic angle. Five constants already fixed determinate the nominal scanning law of Gaia: The inertial spin rate (1°/min) that describe the rotation of the spacecraft around an axis perpendicular to those of the two fields of view, the solar-aspect angle (45°) that is the angle between the Sun and the spacecraft rotation axis, the precession period (63.12 days) which is the precession of the spin axis around the Sun-Earth direction. Two other constants are still free parameters: the initial spin phase, and the initial precession angle that will be fixed at the start of the nominal science operations. These latter are constraint by scientific outcome (e.g. possibility of performing test of fundamental physics) together with operational requirements (downlink to Earth windows). Several sets of observations of specific NEOs will hence be provided according to the initial precession angle. The purpose here is to study the statistical impact of the initial precession angle on the error propagation and on the collision probability, especially for PHAs. We will also analyse the advantage of combining space-based to ground-based observation over long term, as well as in short term from observations in alert. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011sssg.confE...1B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011sssg.confE...1B">Near-Earth Asteroids Astrometry with Gaia</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Bancelin, D.; Hestroffer, D.; Thuillot, W. 2011-05-01 Potentially Hazardous Asteroids (PHAs) are Near-Earth Asteroids caraterised by a Minimum Orbital Intersection Distance (MOID) with Earth less to 0.05 A.U and an absolute magnitude H<22. Those objects have sometimes a so significant close approach with Earth that they can be put on a chaotic orbit. This kind of orbit is very sensitive for exemple to the initial conditions, to the planetary theory used (for instance JPL's model versus IMCCE's model) or even to the numerical integrator used (Lie Series, Bulirsch-Stoer or Radau). New observations (optical, radar, flyby or satellite mission) can improve those orbits and reduce the uncertainties on the Keplerian elements.The Gaia mission is an astrometric mission that will be launched in 2012 and will observe a large number of Solar System Objects down to magnitude V≤20. During the 5-year mission, Gaia will continuously scan the sky with a specific strategy: objects will be observed from two lines of sight separated with a constant basic angle. Five constants already fixed determinate the nominal scanning law of Gaia: The inertial spin rate (1°/min) that describe the rotation of the spacecraft around an axis perpendicular to those of the two fields of view, the solar-aspect angle (45°) that is the angle between the Sun and the spacecraft rotation axis, the precession period (63.12 days) which is the precession of the spin axis around the Sun-Earth direction. Two other constants are still free parameters: the initial spin phase, and the initial precession angle that will be fixed at the start of the nominal science operations. These latter are constraint by scientific outcome (e.g. possibility of performing test of fundamental physics) together with operational requirements (downlink to Earth windows). Several sets of observations of specific NEOs will hence be provided according to the initial precession angle. The purpose here is to study the statistical impact of the initial precession angle on the error propagation and on the collision probability, especially for PHAs. We will also analyse the advantage of combining space-based to ground-based observation over long term, as well as in short term from observations in alert. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/EJ1056957.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/EJ1056957.pdf">Continuity and Change: Building a Quality Culture in the Romanian Educational System</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Bunda, Nicoleta Ramona; Baciu, Livia Loredana 2009-01-01 Educational objectives, like educational quality, are contextual and evolving--they may exhibit both continuity and change. This paper capitalizes on the role of neo-institutionalism and on the contribution of Douglass North (one major representative of the neo-institutionalism trend) in identifying the institutional impact upon cognitive… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E1702S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E1702S">Asteroid Redirect Mission - Next Major stepping-stone to Human Exploration of NEOs and beyond</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Sanchez, Natalia 2016-07-01 In response to NASA's Asteroid Initiative, an Asteroid Redirect and Robotic Mission (ARRM) is being studied by a NASA cohort, led by JPL, to enable the capture a multi-ton boulder from the surface of a Near-Earth Asteroid and return it to cislunar space for subsequent human and robotic exploration. The mission would boost our understanding of NEOs and develop technological capabilities for Planetary Defense, shall a NEO come up on a collision course. The benefits of this mission can extend our capabilities to explore farther into space, as well as create a new commercial sector in Space Mining, which would make materials in Space available for our use. ARRM would leverage and advance current knowledge of higher-efficiency propulsion systems with a new Solar Electric Propulsion demonstration (similar to that on the Dawn spacecraft) to be incorporated into future Mars Missions. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002iaf..confE.198K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002iaf..confE.198K">MACSAT - A Near Equatorial Earth Observation Mission</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Kim, B. J.; Park, S.; Kim, E.-E.; Park, W.; Chang, H.; Seon, J. MACSAT mission was initiated by Malaysia to launch a high-resolution remote sensing satellite into Near Equatorial Orbit (NEO). Due to its geographical location, Malaysia can have large benefits from NEO satellite operation. From the baseline circular orbit of 685 km altitude with 7 degrees of inclination, the neighboring regions around Malaysian territory can be frequently monitored. The equatorial environment around the globe can also be regularly observed with unique revisit characteristics. The primary mission objective of MACSAT program is to develop and validate technologies for a near equatorial orbit remote sensing satellite system. MACSAT is optimally designed to accommodate an electro-optic Earth observation payload, Medium-sized Aperture Camera (MAC). Malaysian and Korean joint engineering teams are formed for the effective implementation of the satellite system. An integrated team approach is adopted for the joint development for MACSAT. MAC is a pushbroom type camera with 2.5 m of Ground Sampling Distance (GSD) in panchromatic band and 5 m of GSD in four multi-spectral bands. The satellite platform is a mini-class satellite. Including MAC payload, the satellite weighs under 200 kg. Spacecraft bus is designed optimally to support payload operations during 3 years of mission life. The payload has 20 km of swath width with +/- 30 o of tilting capability. 32 Gbits of solid state recorder is implemented as the mass image storage. The ground element is an integrated ground station for mission control and payload operation. It is equipped with S- band up/down link for commanding and telemetry reception as well as 30 Mbps class X-band down link for image reception and processing. The MACSAT system is capable of generating 1:25,000-scale image maps. It is also anticipated to have capability for cross-track stereo imaging for Digital elevation Model (DEM) generation. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004SASS...23..151C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004SASS...23..151C">Statistical Properties of a Two-Stage Procedure for Creating Sky Flats</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Crawford, R. W.; Trueblood, M. 2004-05-01 Accurate flat fielding is an essential factor in image calibration and good photometry, yet no single method for creating flat fields is both practical and effective in all cases. At Winer Observatory, robotic telescope opera- tion and the research program of Near Earth Object follow-up astrometry favor the use of sky flats formed from the many images that are acquired during a night. This paper reviews the statistical properties of the median-combine process used to create sky flats and discusses a computationally efficient procedure for two-stage combining of many images to form sky flats with relatively high signal-to-noise ratio (SNR). This procedure is in use at Winer for the flat field calibration of unfiltered images taken for NEO follow-up astrometry. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011IzVF...54j.103B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011IzVF...54j.103B">A search of impact orbits for near-Earth objects by means of minimization of two target functions product. (Russian Title: Поиск столкновительных орбит астероидов, сближающихся с Землей, с помощью минимизации произведения двух целевых функций)</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Baturin, A. P. 2011-07-01 The method of NEO's impact orbits search based on two target functions product minimization is presented. These functions are: a square of asteroid-Earth distance at the moment of close approach and a sum of squares of angular residuals. Besides, the method includes a minimization of asteroid-Earth distance's square in function of time alone when initial motion parameters are fixed. Both minimizations are carrying out in turn each by another. The testing of method has been made on the problem of Apophis's impact orbit search. The results of the testing have depicted an effectivity of presented method in searching of impact orbits for the Apophis's Earth encounters in 2036 and 2037. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120004034','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120004034">Assessment of DSN Communication Coverage for Space Missions to Potentially Hazardous Asteroids</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Kegege, Obadiah; Bittner, David; Gati, Frank; Bhasin, Kul 2012-01-01 A communication coverage gap exists for Deep Space Network (DSN) antennas. This communication coverage gap is on the southern hemisphere, centered at approximate latitude of -47deg and longitude of -45deg. The area of this communication gap varies depending on the altitude from the Earth s surface. There are no current planetary space missions that fall within the DSN communication gap because planetary bodies in the Solar system lie near the ecliptic plane. However, some asteroids orbits are not confined to the ecliptic plane. In recent years, Potentially Hazardous Asteroids (PHAs) have passed within 100,000 km of the Earth. NASA s future space exploration goals include a manned mission to asteroids. It is important to ensure reliable and redundant communication coverage/capabilities for manned space missions to dangerous asteroids that make a sequence of close Earth encounters. In this paper, we will describe simulations performed to determine whether near-Earth objects (NEO) that have been classified as PHAs fall within the DSN communication coverage gap. In the study, we reviewed literature for a number of PHAs, generated binary ephemeris for selected PHAs using JPL s HORIZONS tool, and created their trajectories using Satellite Took Kit (STK). The results show that some of the PHAs fall within DSN communication coverage gap. This paper presents the simulation results and our analyses </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140002479','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140002479">Lunar Polar In Situ Resource Utilization (ISRU) as a Stepping Stone for Human Exploration</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Sanders, Gerald B. 2013-01-01 A major emphasis of NASA is to extend and expand human exploration across the solar system. While specific destinations are still being discussed as to what comes first, it is imperative that NASA create new technologies and approaches that make space exploration affordable and sustainable. Critical to achieving affordable and sustainable exploration beyond low Earth orbit (LEO) are the development of technologies and approaches for advanced robotics, power, propulsion, habitats, life support, and especially, space resource utilization systems. Space resources and how to use them, often called In-Situ Resource Utilization (ISRU), can have a tremendous beneficial impact on robotic and human exploration of the Moon, Mars, Phobos, and Near Earth Objects (NEOs), while at the same time helping to solve terrestrial challenges and enabling commercial space activities. The search for lunar resources, demonstration of extraterrestrial mining, and the utilization of resource-derived products, especially from polar volatiles, can be a stepping stone for subsequent human exploration missions to other destinations of interest due to the proximity of the Moon, complimentary environments and resources, and the demonstration of critical technologies, processes, and operations. ISRU and the Moon: There are four main areas of development interest with respect to finding, obtaining, extracting, and using space resources: Prospecting for resources, Production of mission critical consumables like propellants and life support gases, Civil engineering and construction, and Energy production, storage, and transfer. The search for potential resources and the production of mission critical consumables are the primary focus of current NASA technology and system development activities since they provide the greatest initial reduction in mission mass, cost, and risk. Because of the proximity of the Moon, understanding lunar resources and developing, demonstrating, and implementing lunar ISRU provides a near and early opportunity to perform the following that are applicable to other human exploration mission destinations: Identify and characterize resources, how they are distributed, and the material, location and environment in which they are found; Demonstrate concepts, technologies, and hardware that can reduce the cost and risk of human exploration beyond Earth orbit; Use the Moon for operation experience and mission validation for much longer missions that are farther from Earth Develop and evolve ISRU to support sustained, economical human presence beyond Earth's orbit, including promoting space commercialization As Table 1 depicts, the Moon provides environments and resources applicable to Mars and NEOs. Two lunar ISRU resource and product pathways that have notable synergism with NEO, Phobos/Demos, and Mars ISRU are oxygen/metal extraction from regolith, and water/volatile extraction from lunar polar materials. To minimize the risk of developing and incorporating ISRU into human missions, a phased implementation plan is recommended that starts with prospecting and demonstrating critical technologies on robotic and human missions, then performing pilot scale operations (in non-mission critical roles) to enhance exploration mission capabilities, leading to full utilization of space resources in mission critical roles. Which lunar ISRU pathway is followed will depend on the results of early resource prospecting/proof-ofconcept mission(s), and long-term human exploration plans. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AcAau.146...73T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AcAau.146...73T">A Delta-V map of the known Main Belt Asteroids</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Taylor, Anthony; McDowell, Jonathan C.; Elvis, Martin 2018-05-01 With the lowered costs of rocket technology and the commercialization of the space industry, asteroid mining is becoming both feasible and potentially profitable. Although the first targets for mining will be the most accessible near Earth objects (NEOs), the Main Belt contains 106 times more material by mass. The large scale expansion of this new asteroid mining industry is contingent on being able to rendezvous with Main Belt asteroids (MBAs), and so on the velocity change required of mining spacecraft (delta-v). This paper develops two different flight burn schemes, both starting from Low Earth Orbit (LEO) and ending with a successful MBA rendezvous. These methods are then applied to the ∼700,000 asteroids in the Minor Planet Center (MPC) database with well-determined orbits to find low delta-v mining targets among the MBAs. There are 3986 potential MBA targets with a delta-v < 8 km s-1 , but the distribution is steep and reduces to just 4 with delta-v < 7 km s-1. The two burn methods are compared and the orbital parameters of low delta-v MBAs are explored. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMNH11A1901B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMNH11A1901B">Roadmap for an EArth Defense Initiative (READI)</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Burke, J. D.; Hussain, A.; Soni, A.; Johnson-Freese, J.; Faull, J.; Schmidt, N.; Wilson, T.; Thangavelu, M. 2015-12-01 During the 2015 Space Studies Program of the International Space University, a team of thirty-four participants from seventeen countries carried out a team project on the subject of planetary defense against near-Earth object impacts. The READI Project presents the components of a complete architecture representing practical future strategies and methods for protecting our planet and life as we know it. The findings and recommendations of the project are as follows: for detection and tracking, add infrared instruments in space and radar in Earth's southern hemisphere, as well as dedicated ground telescopes and a program for spectroscopic and other characterization of asteroids and comets; for deflection, develop and space-qualify kinetic and nuclear interceptors, as well as long-range laser ablators; for education and outreach, develop programs aimed at the cohort of children aged 6-15 and their parents; and for evacuation and recovery, provide distributed shelters and increased emergency planning. The project recognizes that the enactment of any deflection strategy would require significant international collaboration; thus, we recommend the formation of a Mitigation Action Group (MAG) in addition to the existing organizations IAWN and SMPAG. The MAG should be chartered to recommend deflection strategies to the UN Security Council in the event of an imminent NEO impact and, upon approval, to lead international deflection action. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170005384','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170005384">Meteoroid Bulk Density and Ceplecha Types</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Blaauw, R. C.; Moser, D. E.; Moorhead, A. V. 2017-01-01 The determination of asteroid bulk density is an important aspect of Near Earth Object (NEO) characterization. A fraction of meteoroids originate from asteroids (including some NEOs), thus in lieu of mutual perturbations, satellites, or expensive spacecraft missions, a study of meteoroid bulk densities can potentially provide useful insights into the densities of NEOs and PHOs (Potentially Hazardous Objects). Meteoroid bulk density is still inherently difficult to measure, and is most often determined by modeling the ablation of the meteoroid. One approach towards determining a meteoroid density distribution entails using a more easily measured proxy for the densities, then calibrating the proxy with known densities from meteorite falls, ablation modelling, and other sources. An obvious proxy choice is the Ceplecha type, KB (Ceplecha, 1958), which is thought to indicate the strength of a meteoroid and often correlated to different bulk densities in literature. KB is calculated using the air density at the beginning height of the meteor, the initial velocity, and the zenith angle of the radiant; quantities more readily determined than meteoroid bulk density itself. Numerical values of K(sub B) are sorted into groups (A, B, C, etc.), which have been matched to meteorite falls or meteor showers with known composition such as the porous Draconids. An extensive survey was conducted to establish the strength of the relationship between bulk density and K(sub B), specifically looking at those that additionally determined K(sub B) for the meteors. In examining the modeling of high-resolution meteor data from Kikwaya et al. (2011), the correlation between K(sub B) and bulk density was not as strong as hoped. However, a distinct split by dynamical type was seen with Jovian Tisserand parameter (T(sub J)), with meteoroids from Halley Type comets (T(sub J) < 2) exhibiting much lower bulk densities than those originating from Jupiter Family comets and asteroids (T(sub J) > 2). Therefore, this work indicates that the dynamical classification of a meteoroid is a better indicator of the density than the strength proxy, a somewhat surprising result. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999BAAA...43....7O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999BAAA...43....7O">El destino del asteroide Albert (719)</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Orellana, R. B.; Melita, M. D.; Brunini, A. Albert is the only numbered asteroid that remains lost at present. This object has been discovered while it was making a close apporach to the Earth by Johann Palisa in the Imperial Observatory of Vienna. According to the standard procedure of the time, a number was assigned to it shortly after a preliminar orbit has been obtained and it was named after a great benefactor of Imperial Observatory, Baron Albert von Rothschild. In this work we analyze why this body could not be recovered in its subsequent approaches to the Earth. Basicaly the cause of the loss can be summarized as follows. Given the high absolute magnitude of the object it can only be observed when it is close to the Earth. But naturally, at the close approches, the uncertanty in the position in the celestial sphere is the greatest due to a parallax effect. We have estimated the uncertanty in R.A. and declination by the non-linear propagation of the initial obervational uncertanty. We have determined that, when the aparent magnitude was low enough to observe the object with the instruments available at the time, the uncertainty region exceeded noticeably the region where it was searched. Regarding its possible recovery at present, the uncertainty in its position practicaly covers the whole sky. Nevertheless, the plane of the orbit is bounded in a narrow strip for a considerable length of time, which makes its recovery posible in old plates. The causes of the loss of Albert (719) are common to all NEO's, which is distintive about it is that it was numbered after just a few obervations, while at present the standard procedure requires that the orbit should be very well established before a denomination is given. Given the almost imposibility of its systematic recovery, in the future Albert (719) might be the first asteroid whose denomination is reassigned to another object. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ATel.4623....1H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ATel.4623....1H">Physical characterization of (333358) 2001 WN1: a large, possibly water-rich, low delta-V near-Earth asteroid.</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Hicks, M.; Dombroski, D. 2012-12-01 The near-Earth asteroid (333358) 2001 WN1 was discovered on 2001 November 17 by the LINEAR NEO survey (MPEC 2001-W30). We obtained one night of Bessel BVRI on 2012 November 25 at the JPL Table Mountain Observatory (TMO) 0.6-m telescope. The observational circumstances are summarized in Table 1, with heliocentric, geocentric, solar phase angle, lunar elongation, and expected V magnitude as computed by the JPL HORIZONS ephemeris service. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080012638','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080012638">Mission Analysis for the Don Quijote Phase-A Study</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Cano, Juan L.; Sanchez, Mariano; Cornara, Stefania; Carnelli, Ian 2007-01-01 The Don Quijote Phase-A study is a definition study funded by ESA and devoted to the analysis of the possibilities to deflect a Near Earth Object (NEO) in the range of 300-800 m diameter. DEIMOS Space S.L. and EADS Astrium have teamed up within this study to form one of the three consortia that have analyzed these aspects for ESA. Target asteroids for the mission are 1989 ML, 2002 AT4 and Apophis. This paper presents the mission analysis activities within the consortium providing: low-thrust interplanetary rendezvous Orbiter trajectories to the target asteroids, ballistic interplanetary trajectories for the Impactor, Orbiter arrival description at the asteroids, Orbiter stable orbits characterization at the asteroid, deflection determination by means of a Radio Science Experiment (RSE) as well as the mission timelines and overall mission scenarios. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100040302','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100040302">Extravehicular Activity Systems Education and Public Outreach in Support of NASA's STEM Initiatives</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Paul, Heather L. 2011-01-01 The exploration activities associated with NASA?s goals to return to the Moon, travel to Mars, or explore Near Earth Objects (NEOs) will involve the need for human-supported space and surface extravehicular activities (EVAs). The technology development and human element associated with these exploration missions provide fantastic content to promote science, technology, engineering, and math (STEM). As NASA Administrator Charles F. Bolden remarked on December 9, 2009, "We....need to provide the educational and experiential stepping-stones to inspire the next generation of scientists, engineers, and leaders in STEM fields." The EVA Systems Project actively supports this initiative by providing subject matter experts and hands-on, interactive presentations to educate students, educators, and the general public about the design challenges encountered as NASA develops EVA hardware for these missions. This paper summarizes these education and public efforts. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999DDA....30.0702M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999DDA....30.0702M">Asteroid 1997 XF11 Could Collide with Earth</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Marsden, B. G. 1999-09-01 Early in 1998, the 2-km asteroid 1997 XF11 became of interest as a possible danger to the earth because it would clearly pass within--possibly well within--the earth's sphere of influence on 2028 Oct. 26 (IAUC 6837). Given the usual model of the solar system, the 2028 passage was entirely predictable in that there was then no possibility of collision with the earth (IAUC 6879). Nevertheless, despite this predictability, several colleagues insisted on estimating impact probabilities, with results ranging from 10(-3) to 10(-1117) ; although this latter figure by Muinonen may be technically correct, it surely invites the imagination of bizarre scenarios that would increase it. Surprisingly, despite a stated desire for ``peer review'' of pronouncements of an asteroid hazard, there was no consideration that 1997 XF11 might have posed a danger to the earth a few years after 2028. Given the 88-day arc of observations, the uncertainty in the 2028 miss distance meant that the object's revolution period, currently 1.73 years, could subsequently have been anything from 1.53 to 1.99 years. Furthermore, the essentially linear annual change of 4000 km in the minimum distance between the earth's orbit and the object's descending node would reduce this distance to zero during the late 2030s. Given the possibility of a post-2028 earth-resonant period such as 5/3, 7/4, 9/5 or 12/7 years, it was also predictable that there existed trajectories for 1997 XF11, entirely consistent with the available observations, that would yield an earth impact during this timeframe. A possible deep impact in 2040, a grazing impact in 2037 and other passages within 2 or 3 earth radii were in fact found. Although the chaos induced in 2028 renders the calculation of impact probabilities rather difficult, a simplistic argument gives a value of about 10(-5) in at least one of the relevant years (albeit at a very specific time). This is larger than the estimated annual 10(-6) impact probability for unknown 2-km asteroids. The discovery and incorporation of observations from 1990 (IAUC 6839) immediately eliminated the possibility of an impact by 1997 XF11 for several millennia. An object in a short-period orbit destined to strike the earth is likely to make other close approaches beforehand. Important lessons to learn from the 1997 XF11 ``fiasco'' are that considerations of simple dynamics and geometry are at least as important as probabilistic estimates, and that there is a need to ensure that searches are made for prediscovery images and that an aggressive observational follow-up program is carried out for new NEO discoveries that may seem only an indirect threat. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/22525602-outflows-sodium-excess-objects','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22525602-outflows-sodium-excess-objects">OUTFLOWS IN SODIUM EXCESS OBJECTS</a> <a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Park, Jongwon; Yi, Sukyoung K.; Jeong, Hyunjin, E-mail: yi@yonsei.ac.kr 2015-08-10 Van Dokkum and Conroy revisited the unexpectedly strong Na i lines at 8200 Å found in some giant elliptical galaxies and interpreted them as evidence for an unusually bottom-heavy initial mass function. Jeong et al. later found a large population of galaxies showing equally extraordinary Na D doublet absorption lines at 5900 Å (Na D excess objects: NEOs) and showed that their origins can be different for different types of galaxies. While a Na D excess seems to be related to the interstellar medium (ISM) in late-type galaxies, smooth-looking early-type NEOs show little or no dust extinction and hence nomore » compelling signs of ISM contributions. To further test this finding, we measured the Doppler components in the Na D lines. We hypothesized that the ISM would have a better (albeit not definite) chance of showing a blueshift Doppler departure from the bulk of the stellar population due to outflow caused by either star formation or AGN activities. Many of the late-type NEOs clearly show blueshift in their Na D lines, which is consistent with the former interpretation that the Na D excess found in them is related to gas outflow caused by star formation. On the contrary, smooth-looking early-type NEOs do not show any notable Doppler components, which is also consistent with the interpretation of Jeong et al. that the Na D excess in early-type NEOs is likely not related to ISM activities but is purely stellar in origin.« less </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active">16</li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active">17</li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20110007855&hterms=1044&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D%2526%25231044','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20110007855&hterms=1044&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D%2526%25231044">Simple, Robust Cryogenic Propellant Depot for Near Term Applications</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> McLean, Christopher; Pitchford, Brian; Mustafi, Shuvo; Wollen, Mark; Walls, Laurie; Schmidt, Jeff 2011-01-01 The ability to refuel cryogenic propulsion stages on-orbit provides an innovative paradigm shift for space transportation supporting National Aeronautics and Space Administration s (NASA) Exploration program as well as deep space robotic, national security and commercial missions. Refueling enables large beyond low Earth orbit (LEO) missions without requiring super heavy lift vehicles that must continuously grow to support increasing mission demands as America s exploration transitions from early Lagrange point missions to near Earth objects (NEO), the lunar surface and eventually Mars. Earth-to-orbit launch can be optimized to provide competitive, cost-effective solutions that allow sustained exploration. This paper describes an experimental platform developed to demonstrate the major technologies required for fuel depot technology. This test bed is capable of transferring residual liquid hydrogen (LH2) or liquid oxygen (LO2) from a Centaur upper stage, and storage in a secondary tank for up to one year on-orbit. A dedicated, flight heritage spacecraft bus is attached to an Evolved Expendable Launch Vehicle (EELV) Secondary Payload Adapter (ESPA) ring supporting experiments and data collection. This platform can be deployed as early as Q1 2013. The propellant depot design described in this paper can be deployed affordably this decade supporting missions to Earth-Moon Lagrange points and lunar fly by. The same depot concept can be scaled up to support more demanding missions and launch capabilities. The enabling depot design features, technologies and concept of operations are described. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-as09-26a-3768a.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-as09-26a-3768a.html">Apollo 9 Mission image - S0-65 Multispectral Photography - Mexico</a> <a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a> 2009-02-19 AS09-26A-3768A (10 March 1969) --- Color infrared photograph of Mexico: Cerro Malinche, east end of neo-volcanic plateau, as seen from the Apollo 9 spacecraft during its 109th revolution of Earth. This picture was taken as a part of the SO65 Multispectral Terrain Photography Experiment. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IAUGA..2255911K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IAUGA..2255911K">Physical characterization of fast rotator NEOs</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Kikwaya Eluo, Jean-Baptiste; Hergenrother, Carl W. 2015-08-01 Understanding the physical characteristics of fast rotator NEOs (sub-km sizes with H > 22) is important for two reasons: to establish properties that can constraint models of their potential hazard, and to learn about the origin and the evolution of the solar system. Technically it is difficult to cover different ranges of wavelengths using one telescope with one instrument. Setting up a network of telescopes with different instruments observing simultaneously the same object will efficiently contribute to the characterization of NEOs.ART (Arizona Robotic Telescope) is a University of Arizona initiative whose goal is to use local 2-m size telescopes to provide near real-time observations of Target of Opportunity objects covering the visible and the near- infrared wavelengths. We plan to use three telescopes of the ART project to observe fast rotator NEOs: 1) VATT (Vatican Advanced Technology Telescope) at Mount Graham (longitude: -109.8719, latitude: 32.7016, elevation: 10469 feet) with VATT-4K optical imager for photometry to estimate colors, lightcurves to get the rotation rate, and estimate the phase angle function of NEOs, 2) Bok 2.3 m at Kitt Peak (longitude: -111.6004, latitude: 31.9629, elevation: 6795 feet) with BCSpec (Boller & Chivens Spectrograph) for visible spectroscopy, and 3) Kuiper 1.5-m at Mount Bigelow (longitude: -110.7345, latitude: 32.4165, elevation: 8235 feet) with a near-infrared instrument.We report here the preliminary results of several NEOs whose rotation rate, color, and type have been estimated using photometry with images recorded with VATT-4K. 2009 SQ104 has a rotation rate of 6.85+/- 0.03 h, 2014 AY28 has a rotation rate of 0.91 +/- 0.02 h, 2014 EC of 0.54 +/-0.04 h, 2014 FA44 of 3.45 +/- 0.05 h, 2014 KS40 of 1.11 +/- 0.06 h, 2011 PT of 0.17 +/- 0.05 h, 2014 SC324 of 0.36 +/- 0.43 h, 2014 WF201 of 1.00 +/- 0.03 h. Of these objects, 2014 HM2, 2014 FA, 2014 SB145, 2011 PT fall among X-type asteroids; 2014 KS, 2014 WF are likely to be C-type; and 2014 SC 324 is a D-type. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070008273','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070008273">Working Group Reports and Presentations: Asteroids</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Lewis, John 2006-01-01 The study and utilization of asteroids will be an economical way to enable exploration of the solar system and extend human presence in space. There are thousands of near-earth objects (NEOs) that we will be able to reach. They offer resources, transportation, and exploration platforms, but also present a potential threat to civilization. Asteroids play a catastrophic role in the history of the Earth. Geological records indicate a regular history of massive impacts, which astronomical observations confirm is likely to continue with potentially devastating consequences. However, study and exploration of near earth asteroids can significantly increase advanced warning of an Earth impact, and potentially lead to the technology necessary to avert such a collision. Efforts to detect and prevent cataclysmic events would tend to foster and likely require international cooperation toward a unified goal of self-preservation. Exploration of asteroids will help us to understand our history and perhaps save our future. Besides the obvious and compelling scientific and security drivers for asteroid research and exploration, there are numerous engineering and industrial applications for near-term asteroid exploration. We have strong evidence that some asteroids are metal rich. Some are water and organic rich. They can be reached with a very low fuel cost compared to other solar system destinations. Once we reach them, there are efficient, simple extraction technologies available that would facilitate utilization. In addition, the costs of returning extracted resources from asteroids will be a fraction of the cost to return similar resources from the moon to Low Earth Orbit (LEO). These raw materials, extracted and shipped at relatively low cost, can be used to manufacture structures, fuel, and products which could be used to foster mankind s further exploration of the solar system. Asteroids also have the potential to offer transport to several destinations in the solar system. In addition to Mars and the Asteroid belt, it is possible to nudge the orbits of NEOs to provide convenient transport to other destinations. Resources to support life on these long voyages may be gathered from the host asteroid itself. As asteroids travel over a wide range of inclinations and ranges, they offer possible platforms to perform scientific investigations. These include unique vantage point observations of the sun and planets. These observations can help us to understand solar activity and space weather. They also afford us an opportunity to see how the earth looks from afar with different perspectives. When we look for planets outside of our solar system, these observations will help us to calibrate our data. Asteroids may also be used as platforms to support very long baseline interferometry with unprecedented angular resolutions. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ahs..book..103T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ahs..book..103T">The Relationship Between the Origins of Life on Earth and the Possibility of Life on Other Planets: A Nineteenth-Century Perspective</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Tirard, Stéphane In this chapter we examine how, during the second part of the nineteenth century and the beginning of the twentieth century, assumptions about the origins of life were specifically linked to the development of theories of evolution and how these conceptions influenced assumptions about the possibility of life on other planets. First we present the theories of the origins of life of Charles Darwin (1809-1882) and Herbert Spencer (1820-1903) and underline how they were linked to the knowledge of physical and chemical conditions of environments. These two examples lead us to think about the relationship between the origin of life, evolutionary biology, and geology, particularly the uniformitarian principle. An important point is the extension of the comprehension of terrestrial conditions of emergence and evolution of life to other planets. We claim that there was a sort of extended uniformitarian principle, based not only on time, but also on space. Second, after a brief look at panspermia theory, we compare two examples of assumptions about life on other planets. The French astronomer Camille Flammarion (1842-1925) and the French biologist Edmond Perrier (1844-1921) presented views that consisted in complex analogies between life on Earth and life on other planets. We analyze how they used neo-Lamarckian biological concepts to imagine living beings in other worlds. Each planet is characterized by a particular stage of biological evolution that they deduce from the state of living beings on Earth. The two scientists explained these different states with neo-Lamarckian principles, which were based on environmental constraints on organisms. Therefore these descriptions presented a sort of history of life, including the past and the future. We claim that their assumptions could be some intellectual exercises testing neo-Lamarckian theories. Moreover the description of human beings on other planets, and particularly the Martian epianthropus presented by Perrier, were complex utopias, which finally spoke about us and about an ideal future. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/AD1018118','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/AD1018118">Noncombatant Evacuation Operations (NEO) Decision-Making Process Effects on Efficiency</a> <a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a> 2012-02-15 the eastern coast of Japan. On 12 March, the Fukushima Daiichi nuclear power plant experienced explosions and fires within four reactors.51 Over... awareness , and understanding the mission objectives.43 The following outlines recent NEO successes and failures. First, a strategic look at the evacuation... Daiichi nuclear power plant. Over the next 30 days, the JTF and embassy worked intensely to develop a comprehensive plan overcoming many of the </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20070034844&hterms=financial+autonomy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dfinancial%2Bautonomy','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20070034844&hterms=financial+autonomy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dfinancial%2Bautonomy">Near-Earth Asteroid Tracking with the Maui Space Surveillance System (NEAT/MSSS)</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Helin, Eleanor F.; Pravdo, Steven H.; Lawrence, Kenneth J.; Hicks, Michael D. 2001-01-01 Over the last year the Jet Propulsion Laboratory's (JPL) Near-Earth Asteroid Tracking (NEAT) program has made significant progress and now consists of two simultaneously-operating, autonomous search systems on the 1.2-m (48") telescopes: on the Maui Space Surveillance System (NEAT/MSSS) and NEAT/Palomar on the Palomar Observatory's Oschin telescope. This paper will focus exclusively on the NEAT/MSSS system. NEAT/MSSS is operated as a partnership between NASA/JPL and the United States Air Force Research Laboratory (AFRL), utilizing the AFRL 1.2-m telescope on the 3000-m summit of Haleakala, Maui, The USAF Space Command (SPCMD) contributed financial support to build and install the 'NEAT focal reducer' on the MSSS 1.2-m telescope giving it a large field of view (2.5 square degrees), suitable for the near-earth object (NEO),both asteroids and comets, survey. This work was completed in February 2000. AFRL has made a commitment to NEAT/MSSS that allows NEAT to operate full time with the understanding that AFRL participate as partners in NEAT/MSSS and have use of the NEAT camera system for high priority satellite observations during bright time (parts of 12 nights each month). Currently, NEAT has discovered 42 NEAs including 12 larger than 1-km, 5 Potentially Hazardous Asteroids (PHAs), 6 comets, and nearly 25,000 asteroid detections since March 2000. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20130011629','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20130011629">Environmental Controls and Life Support System (ECLSS) Design for a Multi-Mission Space Exploration Vehicle (MMSEV)</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Stambaugh, Imelda; Baccus, Shelley; Buffington, Jessie; Hood, Andrew; Naids, Adam; Borrego, Melissa; Hanford, Anthony J.; Eckhardt, Brad; Allada, Rama Kumar; Yagoda, Evan 2013-01-01 Engineers at Johnson Space Center (JSC) are developing an Environmental Control and Life Support System (ECLSS) design for the Multi-Mission Space Exploration Vehicle (MMSEV). The purpose of the MMSEV is to extend the human exploration envelope for Lunar, Near Earth Object (NEO), or Deep Space missions by using pressurized exploration vehicles. The MMSEV, formerly known as the Space Exploration Vehicle (SEV), employs ground prototype hardware for various systems and tests it in manned and unmanned configurations. Eventually, the system hardware will evolve and become part of a flight vehicle capable of supporting different design reference missions. This paper will discuss the latest MMSEV ECLSS architectures developed for a variety of design reference missions, any work contributed toward the development of the ECLSS design, lessons learned from testing prototype hardware, and the plan to advance the ECLSS toward a flight design. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120016969','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120016969">Environmental Controls and Life Support System (ECLSS) Design for a Multi-Mission Space Exploration Vehicle (MMSEV)</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Stambaugh, Imelda; Baccus, Shelley; Naids, Adam; Hanford, Anthony 2012-01-01 Engineers at Johnson Space Center (JSC) are developing an Environmental Control and Life Support System (ECLSS) design for the Multi-Mission Space Exploration Vehicle (MMSEV). The purpose of the MMSEV is to extend the human exploration envelope for Lunar, Near Earth Object (NEO), or Deep Space missions by using pressurized exploration vehicles. The MMSEV, formerly known as the Space Exploration Vehicle (SEV), employs ground prototype hardware for various systems and tests it in manned and unmanned configurations. Eventually, the system hardware will evolve and become part of a flight vehicle capable of supporting different design reference missions. This paper will discuss the latest MMSEV ECLSS architectures developed for a variety of design reference missions, any work contributed toward the development of the ECLSS design, lessons learned from testing prototype hardware, and the plan to advance the ECLSS toward a flight design. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007IAUS..236..323L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007IAUS..236..323L">Current NEO surveys</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Larson, Stephen 2007-05-01 The state and discovery rate of current NEO surveys reflects incremental improvements in a number of areas, such as detector size and sensitivity, computing capacity and availability of larger apertures. The result has been an increased discovery rate even with the expected reduction of objects left to discover. There are currently about 10 telescopes ranging in size from 0.5 - 1.5-meters carrying out full or part-time, regular surveying in both hemispheres. The sky is covered between 1-2 times per lunation to V~19, with a band near the ecliptic to V~20.5. We review the current survey programs and their contribution towards the Spaceguard goal of discovering at least 90% of the NEOs larger than 1 km. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IAUGA..2258303H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IAUGA..2258303H">The Pan-STARRS Survey for Transients (PSST)</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Huber, Mark; Carter Chambers, Kenneth; Flewelling, Heather; Smartt, Stephen J.; Smith, Ken; Wright, Darryl 2015-08-01 The Pan-STARRS1 (PS1) Science Consortium finished the 3Pi survey of the whole sky north of -30 degrees between 2010-2014 in grizy (PS1 specific filters) and the PS1 telescope has been running a wide-field survey for near earth objects, funded by NASA through the NEO Observation Program. This survey takes data in a w-band (wide-band filter spanning g,r,i) in dark time, and combinations of r, i, z and y during bright time. We are now processing these data through the Pan-STARRS IPP difference imaging pipeline and recovering stationary transients. Effectively the 3Pi survey for transients that started during the PS1 Science Consortium is being continued under the new NEO optimized operations mode. The observing procedure in this case is to take a quad of exposures, typically 30-45 seconds separated by 10-20 minutes each, typically revealing high confidence transients (greater than 5-sigma) to depths of i~ 20.7, y~18.3 (AB mags). This cadence may be repeated on subsequent nights in a return pointing.Continuing the public release of the first 880 transients from the PS1 3Pi survey during the search period September 2013 - January 2014, beginning February 2015, the transient events using the data from the the Pan-STARRS NEO Science Consortium are now regularly added. These are mostly supernova candidates, but the list also contains some variable stars, AGN, and nuclear transients. The light curves are too sparsely sampled to be of standalone use, but they may be of use to the community in combining with existing data (e.g. Fraser et al. 2013, ApJ, 779, L8), constraining explosion and rise times (e.g. Nicholl et al. 2013, Nature, 502, 346) as well as many being new discoveries.For additional details visit http://star.pst.qub.ac.uk/ps1threepi/ </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20140002056&hterms=gravity+earth&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dgravity%2Bearth','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20140002056&hterms=gravity+earth&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dgravity%2Bearth">Using Gravity Assists in the Earth-moon System as a Gateway to the Solar System</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> McElrath, Timothy P.; Lantoine, Gregory; Landau, Damon; Grebow, Dan; Strange, Nathan; Wilson, Roby; Sims, Jon 2012-01-01 For spacecraft departing the Earth - Moon system, lunar flybys can significantly increase the hyperbolic escape energy (C3, in km (exp 2) /sec (exp 2) ) for a modest increase in flight time. Within approx 2 months, lunar flybys can produce a C3 of approx 2. Over 4 - 6 months, lunar flybys alone can increase the C3 to approx 4.5, or they can provide for additional periapsis burns to increase the C3 from approx 2 -3 to 10 or more, suitable for planetary missions. A lunar flyby departure can be followed by additional delta -V (such as that efficiently provided by a low thrust system, eg. Solar Electric Propulsion (SEP)) to raise the Earth - relative velocity (at a ratio of more than 2:1) before a subsequent Earth flyby, which redirects that velocity to a more distant target, all within not more than a year. This paper describes the applicability of lunar flybys for different flight times and propulsion systems, and illustrates this with instances of past usage and future possibilities. Examples discussed include ISEE-3, Nozomi, STEREO, 2018 Mars studies (which showed an 8% payload increase), and missions to Near Earth Objects (NEOs). In addition, the options for the achieving the initial lunar flyby are systematically discussed, with a view towards their practical use within a compact launch period. In particular, we show that launches to geosynchronous transfer orbit (GTO) as a secondary payload provide a feasible means of obtaining a lunar flyby for an acceptable cost, even for SEP systems that cannot easily deliver large delta-Vs at periapsis. Taken together, these results comprise a myriad of options for increasing the mission performance, by the efficient use of lunar flybys within an acceptable extension of the flight time. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20140002055&hterms=gravity+earth&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dgravity%2Bearth','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20140002055&hterms=gravity+earth&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dgravity%2Bearth">Using Gravity Assists in the Earth-moon System as a Gateway to the Solar System</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> McElrath, Tim; Lantoine, Gregory; Landau, Damon; Grebow, Dan; Strange, Nathan; Wilson, Roby; Sims, Jon 2012-01-01 For spacecraft departing the Earth - Moon system, lunar flybys can significantly increase the hype rbolic escape energy (C3, in km 2 /sec 2 ) for a modest increase in flight time. Within 2 months, lunar flybys can produce a C3 of 2. Over 4 - 6 months, lunar flybys alone can increase the C3 to 4.5, or they can provide for additional periapsis burns to increase the C3 from 2 -3 to 10 or more, suitable for planetary missions. A lunar flyby departure can be followed by additional ? -V (such as that efficiently provided by a low thrust system, eg. Solar Electric Propulsion (SEP)) to raise the Earth - relative velocity (at a ratio of more than 2:1) before a subsequent Earth flyby, which redirects that velocity to a more di stant target, all within not much more than a year. This paper describes the applicability of lunar flybys for different flight times and propulsi on systems, and illustrates this with instances of past usage and future possibilities. Examples discussed i nclude ISEE - 3, Nozomi, STEREO, 2018 Mars studies (which showed an 8% payload increase), and missions to Near Earth Objects (NEOs). In addition, the options for the achieving the initial lunar flyby are systematically discussed, with a view towards their p ractical use with in a compact launch period. In particular, we show that launches to geosynchronous transfer orbit (GTO) as a secondary payload provide a feasible means of obtaining a lunar flyby for an acceptable cost, even for SEP systems that cannot ea sily deliver large ? - Vs at periapsis. Taken together, these results comprise a myriad of options for increasing the mission performance, by the efficient use of lunar flybys within an acceptable extension of the flight time. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4832714N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4832714N">Update on Astrometric Follow-Up at Apache Point Observatory by Adler Planetarium</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Nault, Kristie A.; Brucker, Melissa; Hammergren, Mark 2016-10-01 We began our NEO astrometric follow-up and characterization program in 2014 Q4 using about 500 hours of observing time per year with the Astrophysical Research Consortium (ARC) 3.5m telescope at Apache Point Observatory (APO). Our observing is split into 2 hour blocks approximately every other night for astrometry (this poster) and several half-nights per month for spectroscopy (see poster by M. Hammergren et al.) and light curve studies.For astrometry, we use the ARC Telescope Imaging Camera (ARCTIC) with an SDSS r filter, in 2 hour observing blocks centered around midnight. ARCTIC has a magnitude limit of V~23 in 60s, and we target 20 NEOs per session. ARCTIC has a FOV 1.57 times larger and a readout time half as long as the previous imager, SPIcam, which we used from 2014 Q4 through 2015 Q3. Targets are selected primarily from the Minor Planet Center's (MPC) NEO Confirmation Page (NEOCP), and NEA Observation Planning Aid; we also refer to JPL's What's Observable page, the Spaceguard Priority List and Faint NEOs List, and requests from other observers. To quickly adapt to changing weather and seeing conditions, we create faint, midrange, and bright target lists. Detected NEOs are measured with Astrometrica and internal software, and the astrometry is reported to the MPC.As of June 19, 2016, we have targeted 2264 NEOs, 1955 with provisional designations, 1582 of which were detected. We began observing NEOCP asteroids on January 30, 2016, and have targeted 309, 207 of which were detected. In addition, we serendipitously observed 281 moving objects, 201 of which were identified as previously known objects.This work is based on observations obtained with the Apache Point Observatory 3.5m telescope, which is owned and operated by the Astrophysical Research Consortium. We gratefully acknowledge support from NASA NEOO award NNX14AL17G and thank the University of Chicago Department of Astronomy and Astrophysics for observing time in 2014. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3374794','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3374794">An Urban Neo-Poverty Population-Based Quality of Life and Related Social Characteristics Investigation from Northeast China</a> <a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Ou, Fengrong; Li, Kai; Gao, Qian; Liu, Dan; Li, Jinghai; Hu, Liwen; Wu, Xian; Edmiston, E. Kale; Liu, Yang 2012-01-01 Objective To investigate quality of life (QOL) and related characteristics among an urban neo-poverty population in northeast China, and to compare this population with a traditional poverty cohort. Design The research was a cross-sectional survey executed from June 2005 to October 2007, with a sample of 2940 individuals ages 36 to 55 in three different industrial cities of northeast China. Data were collected on QOL status and sociodemographic characteristics. QOL was assessed using the 36-item Short Form Health Survey (Chinese version). Multiple regression analysis was employed to analyze association between sociodemographic variables and QOL. Results The scores for QOL in the neo-poverty group were higher than those in the traditional poverty group, but lower than those in the general population. When the neo-poverty population was divided into two subgroups by age, 36–45 years and 46–55 years, the differences in QOL scores were not significant. However, there were significant differences in several dimensions between two subgroups according to unemployment time (<5 years and >5 years). Additionally, stepwise regression analysis indicated that disease burden, including disease and medical expenditures, was a common risk factor for declining QOL in the neo-poverty group. Conclusions Despite some limitations, this study provides initial evidence that the QOL of the urban neo-poverty population lies between that of the general population and traditional poverty. QOL of the neo-poverty group approached QOL of the traditional poverty group with increased unemployment years. In addition to decreased income, disease burden is the most important factor influencing QOL status in urban neo-poverty. PMID:22719968 </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040034088&hterms=postdoctoral&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dpostdoctoral','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040034088&hterms=postdoctoral&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dpostdoctoral">Search for Near-Earth Objects with Small Aphelion Distances</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Tholen, David J. 2003-01-01 An essential component of our ability to efficiently find NEOs at small solar elongation is a focal reducer, whose construction is being separately funded by a grant from NSF. This focal reducer will increase the field of view of the 8k CCD mosaic camera from 19 arc min to about 32 arc min at the Cassegrain focus of the University of Hawaii 2.24-m telescope. As of January, all but one of the lenses for the focal reducer were in hand. The final lens had been delayed due to problems with the availability of the rather exotic material out of which the manufacturer was to fabricate the lens. Perhaps as a result of their rush to deliver that final lens, it developed a crack during the annealing process at the manufacturer, thus they had to start over. The total delay in delivery of that last lens was nearly ten months, and therefore the focal reducer was not completed on schedule and could not be used on the telescope this semester. A postdoctoral research associate was recruited to handle the day-to-day operations. The closing date for applications was 2002 December 3 1, and seven were received. One applicant was not qualified, and two were marginal. Of the four qualified candidates, Fabrizio Bernardi stood out as being best qualified. He was a student of Andrea Carusi and had worked on the CINEOS project in Italy, which includes a component of searching for NEOs at small solar elongations. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012asla.book.....C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012asla.book.....C">The Astrobiological Landscape</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Ćirković, Milan M. 2012-06-01 Introduction; Acknowledgements; 1. Astrobiology: the colour out of space?; 2. Cosmology, life, and duration of the past; 3. Cosmology, life, and selection effects; 4. Cosmology, life, and the archipelago; 5. Astrobiology as a natural extension of Darwinism; 6. Rare Earths and the continuity thesis; 7. SETI and its discontents; 8. Natural and artificial: cosmic domain of Arnheim; 9. Astrobiology as the neo-Copernican synthesis?; Index. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017DPS....4911108G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017DPS....4911108G">Measuring the Yarkovsky effect with Las Cumbres Observatory</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Greenstreet, Sarah; Farnocchia, Davide; Lister, Tim 2017-10-01 The Las Cumbres Observatory (LCO) provides an ideal platform for follow-up and characterization of Solar System objects (e.g. asteroids, Kuiper Belt Objects, comets, Near-Earth Objects) and ultimately for the discovery of new objects. We have used LCO's global network of nine 1-meter telescopes to measure the Yarkovsky effect on tens of asteroids through precise astrometric measurements using the Gaia-DR1 catalog, providing lower uncertainty with each detection. The target asteroids were picked through simulated observations each month to determine the objects for which new astrometry would yield the most improvement. The Gaia-DR1 release has greatly improved the quality of the astrometry obtained, making the detection of the Yarkovsky effect more likely and secure by greatly reducing systematic catalog zonal errors. With the release of DR2 next year and the availability of good reference star colors, we will be able to take other more subtle effects into account in the astrometric reduction. In addition, the availability of the Gaia catalog would allow re-measurement of past data with more accurate star catalogs. The amount of Yarkovsky acceleration depends on several physical properties, such as the asteroid spin state, size, mass, and thermal properties, to which detection of the effect can give important constraints. The effect is also important for understanding the transportation of asteroids and meteorites into near-Earth space from the main belt, producing the NEOs and for the formation and evolution of asteroid families. Determining and modeling the Yarkovsky effect can be critical for accurate prediction of asteroid trajectories and even for impact hazard assessment. The measurements made with the help of LCO have significantly increased the number of known asteroids with Yarkovsky detections. LCO is ideally suited to perform these observations due to its ability to monitor several targets over several days by employing dynamic scheduling, weather avoidance, and use of multiple sites around the globe. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150009390','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150009390">The Mission Accessibility of Near-Earth Asteroids</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Barbee, Brent W.; Abell, Paul A.; Adamo, Daniel R.; Mazanek, Daniel D.; Johnson, Lindley N.; Yeomans, Donald K.; Chodas, Paul W.; Chamberlin, Alan B.; Benner, Lance A. M.; Taylor, Patrick; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20150009390'); toggleEditAbsImage('author_20150009390_show'); toggleEditAbsImage('author_20150009390_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20150009390_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20150009390_hide"> 2015-01-01 Astrodynamical Earth departure dates; mission v; mission duration; stay time; etc. Physical I NEO size(?); rotation rate; dust satellites environment; chemistry; etc. Architectural Launch vehicle(s); crew vehicle(s); habitat module(s); budget; etc. Operational Operations experience; abort options profiles; etc. Astrodynamical Accessibility is the starting point for understanding the options and opportunities available to us. Here we shall focus on. Astrodynamical Accessibility.2 Earth departure date between 2015-01-01 and 2040-12-31 Earth departure C3 60 km2s2. Total mission v 12 kms. The total v includes (1) the Earth departure maneuver from a 400 km altitude circular parking orbit, (2) the maneuver to match the NEAs velocity at arrival, (3) the maneuver to depart the NEA and, (4) if necessary, a maneuver to control the atmospheric re-entry speed during Earth return. Total round trip mission duration 450 days. Stay time at the NEA 8 days Earth atmospheric entry speed 12 kms at an altitude of 125 km. A near-Earth asteroid (NEA) that offers at least one trajectory solution meeting those criteria is classified as NHATS-compliant. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170008912','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170008912">Marshall Space Flight Center Technology Capabilities for Use in Space Situational Awareness Activities</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Gagliano, Larry; McLeod, Todd; Hovater, Mary A. 2017-01-01 Marshall performs research, integrates information, matures technologies, and enhances science to bring together a diverse portfolio of products and services of interest for Space Situational Awareness (SSA) and Space Asset Management (SAM), all of which can be accessed through partnerships with Marshall. Integrated Space Situational Awareness and Asset Management (ISSAAM) is an initiative of NASA's Marshall Space Flight Center to improve space situational awareness and space asset management through technical innovation, collaboration, and cooperation with U.S. Government agencies and the global space community. Marshall Space Flight Center provides solutions for complex issues with in-depth capabilities, a broad range of experience, and expertise unique in the world, and all available in one convenient location. NASA has longstanding guidelines that are used to assess space objects. Specifically, Marshall Space Flight Center has the capabilities, facilities and expertise to address the challenges that space objects, such as near-Earth objects (NEO) or Orbital Debris pose. ISSAAM's three pronged approach brings together vital information and in-depth tools working simultaneously toward examining the complex problems encountered in space situational awareness. Marshall's role in managing, understanding and planning includes many projects grouped under each prong area: Database/Analyses/Visualization; Detection/Tracking/ Mitigation/Removal. These are not limited to those listed below. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active">17</li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active">18</li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110010993','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110010993">Methodology and Results of the Near-Earth Object (NEO) Human Space Flight (HSF) Accessible Targets Study (NHATS)</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Barbee, Brent; Mink, Ronald; Adamo, Daniel 2011-01-01 Near-Earth Asteroids (NEAs) have been identified by the current administration as potential destinations for human explorers during the mid-2020s. While the close proximity of these objects' orbits to Earth's orbit creates a risk of highly damaging or catastrophic impacts, it also makes some of these objects particularly accessible to spacecraft departing Earth, and this presents unique opportunities for solar system science and humanity's first ventures beyond cislunar space. Planning such ambitious missions first requires the selection of potentially accessible targets from the growing population of nearly 7,800 NEAs. To accomplish this, NASA is conducting the Near-Earth Object (NEO) Human Space Flight (HSF) Accessible Targets Study (NHATS). Phase I of the NHATS was executed during September of 2010, and Phase II was completed by early March of 2011. The study is ongoing because previously undetected NEAs are being discovered constantly, which has motivated an effort to automate the analysis algorithms in order to provide continuous monitoring of NEA accessibility. The NHATS analysis process consists of a trajectory filter and a minimum maximum estimated size criterion. The trajectory filter employs the method of embedded trajectory grids to compute all possible ballistic round-trip mission trajectories to every NEA in the Jet Propulsion Laboratory (JPL) Small-Body Database (SBDB) and stores all solutions that satisfy the trajectory filter criteria. An NEA must offer at least one qualifying trajectory solution to pass the trajectory filter. The Phase II NHATS filter criteria were purposely chosen to be highly inclusive, requiring Earth departure date between January 1st, 2015 and December 31st, 2040, total round-trip flight time <= 450 days, stay time at the NEA >= 8 days, Earth departure C(sub 3) energy <= 60 km(exp 2)/s(exp 2), total mission delta-v <= 12 km/s (including an Earth departure maneuver from a 400 km altitude circular parking orbit), and a maximum atmospheric re-entry speed of 12 km/s. After determining which NEAs offer at least one trajectory solution meeting the criteria, the estimated size constraint is then imposed whereby those NEAs may only be considered NHATS- qualifying NEAs if their maximum estimated size is >= 30 m. This corresponds to an absolute magnitude H <= 26.5 with an assumed albedo p = 0:05. The following is a brief high-level summary of the Phase II study results. Of the 7,665 NEAs in the SBDB as of February 3rd, 2011, 765 NEAs passed the trajectory filter and yielded a total of 79,157,604 trajectory solutions. The trajectory solutions for each NEA are post-processed into Pork Chop Contour (PCC) plots which show total mission delta-v as a function of Earth departure date and total mission duration. Although the PCC plots necessarily compress a very multi-dimensional design space into a two-dimensional plot, they permit rapid assessment of the breadth and quality of an NEA's available Earth departure season and clearly indicate the regions of the trajectory design space which warrant further analysis and optimization. The PCC plot for the NEA with the greatest number of NHATS-qualifying trajectory solutions, 2000 SG-344, is shown. Of the 765 NEAs which passed the Phase II trajectory filter, a total of 590 NEAs also satisfied the further constraint of maximum estimated size >= 30 m. The distributions of osculating heliocentric orbital semi-major axis (a), eccentricity (e), and inclination (i), for those 590 NEAs are shown. Note that the semi-latus rectum used is equal to alpha (1-e(exp 2)). To further our understanding of round-trip trajectory accessibility dynamics, it is instructive to examine the distribution of the NHATS-Qualifying NEAs according to orbit classification. NEAs are grouped into four orbit families: Atiras (aphelion < 0.983 AU), Atens (aphelion > 0.983 AU, alpha < 1.0 AU), Apollos (perihelion < 1.017 AU, alpha > 1.0 AU), and Amors (1.017 < perihelion < 1.3 AU). Of the 765 NEAhich satisfied the NHATS trajectory criteria, none are Atiras, 193 are Atens (31% of known Atens), 456 are Apollos (11% of known Apollos), and 116 are Amors (4% of known Amors). While Apollos comprise 60% of the NEAs which pass the NHATS trajectory filter and Atens comprise only 25%, the percentages according to orbit family are perhaps more relevant. Note that only 11% of known Apollos passed the trajectory filter while 31% of known Atens passed. These simple statistics alone strongly suggest that Aten orbits possess features which tend to enhance their round-trip trajectory accessibility as compared to Apollos or Amors. This is significant because Atens' orbits cause them to spend considerable time in Earth's daytime sky, making them difficult to discover and track using ground-based observing assets. In this paper we will detail the NHATS analysis algorithms, present and analyze all NHATS results to date, and discuss aspects of HSF mission architecture design for future NEA missions. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110007209','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110007209">NASA Technology Area 07: Human Exploration Destination Systems Roadmap</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Kennedy, Kriss J.; Alexander, Leslie; Landis, Rob; Linne, Diane; Mclemore, Carole; Santiago-Maldonado, Edgardo; Brown, David L. 2011-01-01 This paper gives an overview of the National Aeronautics and Space Administration (NASA) Office of Chief Technologist (OCT) led Space Technology Roadmap definition efforts. This paper will given an executive summary of the technology area 07 (TA07) Human Exploration Destination Systems (HEDS). These are draft roadmaps being reviewed and updated by the National Research Council. Deep-space human exploration missions will require many game changing technologies to enable safe missions, become more independent, and enable intelligent autonomous operations and take advantage of the local resources to become self-sufficient thereby meeting the goal of sustained human presence in space. Taking advantage of in-situ resources enhances and enables revolutionary robotic and human missions beyond the traditional mission architectures and launch vehicle capabilities. Mobility systems will include in-space flying, surface roving, and Extra-vehicular Activity/Extravehicular Robotics (EVA/EVR) mobility. These push missions will take advantage of sustainability and supportability technologies that will allow mission independence to conduct human mission operations either on or near the Earth, in deep space, in the vicinity of Mars, or on the Martian surface while opening up commercialization opportunities in low Earth orbit (LEO) for research, industrial development, academia, and entertainment space industries. The Human Exploration Destination Systems (HEDS) Technology Area (TA) 7 Team has been chartered by the Office of the Chief Technologist (OCT) to strategically roadmap technology investments that will enable sustained human exploration and support NASA s missions and goals for at least the next 25 years. HEDS technologies will enable a sustained human presence for exploring destinations such as remote sites on Earth and beyond including, but not limited to, LaGrange points, low Earth orbit (LEO), high Earth orbit (HEO), geosynchronous orbit (GEO), the Moon, near-Earth objects (NEOs), which > 95% are asteroidal bodies, Phobos, Deimos, Mars, and beyond. The HEDS technology roadmap will strategically guide NASA and other U.S. Government agency technology investments that will result in capabilities enabling human exploration missions to diverse destinations generating high returns on investments. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8757E..0JG','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8757E..0JG">Complex scenes and situations visualization in hierarchical learning algorithm with dynamic 3D NeoAxis engine</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Graham, James; Ternovskiy, Igor V. 2013-06-01 We applied a two stage unsupervised hierarchical learning system to model complex dynamic surveillance and cyber space monitoring systems using a non-commercial version of the NeoAxis visualization software. The hierarchical scene learning and recognition approach is based on hierarchical expectation maximization, and was linked to a 3D graphics engine for validation of learning and classification results and understanding the human - autonomous system relationship. Scene recognition is performed by taking synthetically generated data and feeding it to a dynamic logic algorithm. The algorithm performs hierarchical recognition of the scene by first examining the features of the objects to determine which objects are present, and then determines the scene based on the objects present. This paper presents a framework within which low level data linked to higher-level visualization can provide support to a human operator and be evaluated in a detailed and systematic way. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMNH23D1546C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMNH23D1546C">Perspectives on the Near-Earth Object Impact Hazard After Chelyabinsk</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Chapman, C. R. 2013-12-01 Until this year, the NEO impact hazard had been regarded as a theoretical example of a very low probability high consequence natural disaster. There had been no confirmed examples of fatalities directly due to asteroid or meteoroid strikes. (There still aren't.) The several megaton Tunguska event in 1908 was in a remote, unpopulated place. So human beings have been witnessing only the tiniest analogs of asteroid strikes, the night-sky meteors and occasional bolides, which - on rare occasions - yield meteoritic fragments that puncture holes in roofs. Though the NEO impact hazard has occasionally been treated in the natural hazards literature, interest primarily remained in the planetary science and aerospace communities. The Chelyabinsk asteroid impact on 15 February 2013 was a real disaster, occurring near a city with a population exceeding a million. Well over a thousand people were injured, thousands of buildings suffered at least superficial damage (mainly to windows), schools and sports facilities were closed, and emergency responders swarmed across the city and surrounding rural areas. While the consequences were very small compared with larger natural disasters, which kill tens of thousands of people annually worldwide, this specific case - for the first time - has permitted a calibration of the consequences of the rare impacts asteroid astronomers have been predicting. There now are reasons to expect that impacts by bodies tens of meters in diameter are several times more frequent than had been thought and each impact is more damaging than previously estimated. The Chelyabinsk event, produced by a 20 meter diameter asteroid, specifically suggests that asteroids just 15 meters diameter, or even smaller, could be very dangerous and damaging; indeed, a more common steeper impact angle would have produced more consequential damage on the ground. This contrasts with estimates a decade earlier [NASA NEO Science Definition Team report, 2003] that asteroids smaller than 40 to 50 meters diameter would explode harmlessly in the upper atmosphere. Given the observed size-frequency relation for NEOs, this means that dangerous impacts could be many tens of times more frequent than had been thought. New observing campaigns (e.g. ATLAS) oriented towards finding roughly half of the frequent smaller impactors meters to tens of meters in size during their final days to weeks before impact will soon result in warnings every few years of a potentially dangerous impact, perhaps requiring evacuation or instructions to shelter-in-place, even though most will turn out to be essentially harmless events. Warnings may become even more frequent as prudent emergency managers take into account the large uncertainties in sizes and destructive potential of these 'final plungers.' So emergency management officials around the world should at least be aware of the potential for a NEO impact to produce a real, if generally minor and local, natural disaster. Fortunately, success of the Spaceguard search for civilization-threatening large NEOs (> 1 km diameter) over the last 15 years has nearly retired the risk of global calamity by impact. So attention turns to the much smaller impacts that are far less dangerous, but soon will be frequently predicted and so cannot be ignored. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=medical+AND+student+AND+psychiatry&pg=5&id=EJ804479','ERIC'); return false;" href="https://eric.ed.gov/?q=medical+AND+student+AND+psychiatry&pg=5&id=EJ804479">Do Clinical Evaluations in a Psychiatry Clerkship Favor Students with Positive Personality Characteristics?</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Chibnall, John T.; Blaskiewicz, Robert J. 2008-01-01 Objective: The authors examine associations of personality characteristics, National Board of Medical Examiners subject examination performance, and Objective Structured Clinical Examination performance with clinical evaluations of third-year medical students in a psychiatry clerkship. Methods: Students completed the Revised NEO Personality… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120015348','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120015348">Groundbreaking Mars Sample Return for Science and Human Exploration</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Cohen, Barbara; Draper, David; Eppler, Dean; Treiman, Allan 2012-01-01 Partnerships between science and human exploration have recent heritage for the Moon (Lunar Precursor Robotics Program, LPRP) and nearearth objects (Exploration Precursor Robotics Program, xPRP). Both programs spent appreciable time and effort determining measurements needed or desired before human missions to these destinations. These measurements may be crucial to human health or spacecraft design, or may be desired to better optimize systems designs such as spacesuits or operations. Both LPRP and xPRP recommended measurements from orbit, by landed missions and by sample return. LPRP conducted the Lunar Reconnaissance Orbiter (LRO) and Lunar Crater Observation and Sensing Satellite (LCROSS) missions, providing high-resolution visible imagery, surface and subsurface temperatures, global topography, mapping of possible water ice deposits, and the biological effects of radiation [1]. LPRP also initiated a landed mission to provide dust and regolith properties, local lighting conditions, assessment of resources, and demonstration of precision landing [2]. This mission was canceled in 2006 due to funding shortfalls. For the Moon, adequate samples of rocks and regolith were returned by the Apollo and Luna programs to conduct needed investigations. Many near-earth asteroids (NEAs) have been observed from the Earth and several have been more extensively characterized by close-flying missions and landings (NEAR, Hayabusa, Rosetta). The current Joint Robotic Precursor Activity program is considering activities such as partnering with the New Frontiers mission OSIRIS-Rex to visit a NEA and return a sample to the Earth. However, a strong consensus of the NEO User Team within xPRP was that a dedicated mission to the asteroid targeted by humans is required [3], ideally including regolith sample return for more extensive characterization and testing on the Earth. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012P%26SS...74..121W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012P%26SS...74..121W">Simulation and preparation of surface EVA in reduced gravity at the Marseilles Bay subsea analogue sites</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Weiss, P.; Gardette, B.; Chirié, B.; Collina-Girard, J.; Delauze, H. G. 2012-12-01 Extravehicular activity (EVA) of astronauts during space missions is simulated nowadays underwater in neutral buoyancy facilities. Certain aspects of weightlessness can be reproduced underwater by adding buoyancy to a diver-astronaut, therefore exposing the subject to the difficulties of working without gravity. Such tests were done at the COMEX' test pool in Marseilles in the 1980s to train for a French-Russian mission to the MIR station, for the development of the European HERMES shuttle and the COLUMBUS laboratory. However, space agencies are currently studying missions to other destinations than the International Space Station in orbit, such as the return to the Moon, NEO (near-Earth objects) or Mars. All these objects expose different gravities: Moon has one sixth of Earth's gravity, Mars has a third of Earth's gravity and asteroids have virtually no surface gravity; the astronaut "floats" above the ground. The preparation of such missions calls for a new concept in neutral buoyancy training, not on man-made structures, but on natural terrain, underwater, to simulate EVA operations such as sampling, locomotion or even anchoring in low gravity. Underwater sites can be used not only to simulate the reduced gravity that astronauts will experience during their field trips, also human factors like stress are more realistically reproduced in such environment. The Bay of Marseille hosts several underwater sites that can be used to simulate various geologic morphologies, such as sink-holes which can be used to simulate astronaut descends into craters, caves where explorations of lava tubes can be trained or monolithic rock structures that can be used to test anchoring devices (e.g., near Earth objects). Marseilles with its aerospace and maritime/offshore heritage hosts the necessary logistics and expertise that is needed to perform such simulations underwater in a safe manner (training of astronaut-divers in local test pools, research vessels, subsea robots and submarines). COMEX is currently preparing a space mission simulation in the Marseilles Bay (foreseen in June 2012), and the paper will give an overview of the different underwater analogue sites that are available to the scientific community for the simulation of surface EVA or the test of scientific instruments and devices. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMED52A..01C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMED52A..01C">Integrating Authentic Earth Science Data in Online Visualization Tools and Social Media Networking to Promote Earth Science Education</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Carter, B. L.; Campbell, B.; Chambers, L.; Davis, A.; Riebeek, H.; Ward, K. 2008-12-01 The Goddard Space Flight Center (GSFC) is one of the largest Earth Science research-based institutions in the nation. Along with the research comes a dedicated group of people who are tasked with developing Earth science research-based education and public outreach materials to reach the broadest possible range of audiences. The GSFC Earth science education community makes use of a wide variety of platforms in order to reach their goals of communicating science. These platforms include using social media networking such as Twitter and Facebook, as well as geo-spatial tools such as MY NASA DATA, NASA World Wind, NEO, and Google Earth. Using a wide variety of platforms serves the dual purposes of promoting NASA Earth Science research and making authentic data available to educational communities that otherwise might not otherwise be granted access. Making data available to education communities promotes scientific literacy through the investigation of scientific phenomena using the same data that is used by the scientific community. Data from several NASA missions will be used to demonstrate the ways in which Earth science data are made available for the education community. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050186566','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050186566">Comparison of Detector Technologies for CAPS</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Stockum, Jana L. 2005-01-01 In this paper, several different detectors are examined for use in a Comet/Asteroid Protection System (CAPS), a conceptual study for a possible future space-based system. Each detector will be examined for its future (25 years or more in the future) ability to find and track near-Earth Objects (NEOs) from a space-based detection platform. Within the CAPS study are several teams of people who each focus on different aspects of the system concept. This study s focus is on detection devices. In particular, evaluations on the following devices have been made: charge-coupled devices (CCDs), charge-injected devices (CIDs), superconducting tunneling junctions (STJs), and transition edge sensors (TESs). These devices can be separated into two main categories; the first category includes detectors that are currently being widely utilized, such as CCDs and CIDs. The second category includes experimental detectors, such as STJs and TESs. After the discussion of the detectors themselves, there will be a section devoted to the explicit use of these detectors with CAPS. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20150008058&hterms=Costs+operation&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DCosts%2Boperation','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20150008058&hterms=Costs+operation&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DCosts%2Boperation">Modeling Operations Costs for Human Exploration Architectures</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Shishko, Robert 2013-01-01 Operations and support (O&S) costs for human spaceflight have not received the same attention in the cost estimating community as have development costs. This is unfortunate as O&S costs typically comprise a majority of life-cycle costs (LCC) in such programs as the International Space Station (ISS) and the now-cancelled Constellation Program. Recognizing this, the Constellation Program and NASA HQs supported the development of an O&S cost model specifically for human spaceflight. This model, known as the Exploration Architectures Operations Cost Model (ExAOCM), provided the operations cost estimates for a variety of alternative human missions to the moon, Mars, and Near-Earth Objects (NEOs) in architectural studies. ExAOCM is philosophically based on the DoD Architecture Framework (DoDAF) concepts of operational nodes, systems, operational functions, and milestones. This paper presents some of the historical background surrounding the development of the model, and discusses the underlying structure, its unusual user interface, and lastly, previous examples of its use in the aforementioned architectural studies. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010cosp...38..631K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010cosp...38..631K">Hayabusa Reentry and Recovery of Its Capsule -Quick Report</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Kawaguchi, Junichiro; Yoshikawa, Makoto; Kuninaka, Hitoshi The Hayabusa spacecraft successfully returned to the Earth and re-entered into the atmosphere for sample recovery after also the successful touching-downs to NEO Itokawa in 2005. The reentry occurred on June 13th, and took place in Woomera Prohibited Area (WPA) of Australia. This paper presents how the reentry and recovery operations were performed, and also reports the current status about the sample curation activity. The Hayabusa mission aims at demonstrating key technologies requisite for future real Sample and Return missions. However, the spacecraft adopted the actual Sample and Return flight sequence and was designed to make a world's first round trip to an extra terrestrial object with touching-down and lifting-off. It is the spacecraft propelled by the ion engines aboard for interplanetary cruise. The Hayabusa spacecraft launched in May of 2003 reached NEO Itokawa in September of 2005 via Earth gravity assist in May of 2004. It stayed there for about two and a half months, and performed detailed scientific observation and mapping and determination of the shape. In November of 2005, the spacecraft made two touching-downs and lifting-offs having attempted collection of surface sample. At the second opportunity, the spacecraft directed shooting a projectile. But, due to the programming problem, presumably the projectile was not shot. However, the spacecraft may have captured some small amount of sample particles in a catcher aboard, when the spacecraft made actual touches down to the surface. The spacecraft suffered from fuel leak in December of 2005, and the communication resumed after seven weeks of hiatus. And the ion engines all faced their life by November of 2009, and the project team devised an alternative drive configuration and successfully coped with the difficulty. Despite many hardships, the spacecraft has been operated for return cruise, and it made a reentry for sample recovery this June. The sample catcher was retrieved at WPA and transported back to the curation facility of JAXA. Currently the curators have examined analyzed the catcher recovered. This presentation quickly reports recent status of the spacecraft, capsule and sample analysis. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20050161989&hterms=Cat+scan&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DCat%2Bscan','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20050161989&hterms=Cat+scan&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DCat%2Bscan">Deep Interior Mission: Imaging the Interior of Near-Earth Asteroids Using Radio Reflection Tomography</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Safaeinili, A.; Asphaug, E.; Rodriquez, E.; Gurrola, E.; Belton, M.; Klaasen, K.; Ostro, S.; Plaut, J.; Yeomans, D. 2005-01-01 Near-Earth asteroids are important exploration targets since they provide clues to the evolution of the solar system. They are also of interest since they present a clear danger to Earth. Our mission objective is to image the internal structure of two NEOs using radio reflection tomography (RRT) in order to explore the record of asteroid origin and impact evolution, and to test the fundamental hypothesis that some NEOs are rubble piles rather than consolidated bodies. Our mission s RRT technique is analogous to doing a CAT scan of the asteroid from orbit. Closely sampled radar echoes are processed to yield volumetric maps of mechanical and compositional boundaries, and to measure interior material dielectric properties. The RRT instrument is a radar that operates at 5 and 15 MHz with two 30-m (tip-to-tip) dipole antennas that are used in a cross-dipole configuration. The radar transmitter and receiver electronics have heritage from JPL's MARSIS contribution to Mars Express, and the antenna is similar to systems used in IMAGE and LACE missions. The 5-MHz channel is designed to penetrate greater than 1 km of basaltic rock, and 15-MHz penetrates a few hundred meters or more. In addition to RRT volumetric imaging, we use redundant color cameras to explore the surface expressions of unit boundaries, in order to relate interior radar imaging to what is observable from spacecraft imaging and from Earth. The camera also yields stereo color imaging for geology and RRT-related compositional analysis. Gravity and high fidelity geodesy are used to explore how interior structure is expressed in shape, density, mass distribution and spin. Ion thruster propulsion is utilized by Deep Interior to enable tomographic radar mapping of multiple asteroids. Within the Discovery AO scheduling parameters we identify two targets, S-type 1999 ND43 (approximately 500 m diameter) and V-type 3908 Nyx (approximately 1 km), asteroids whose compositions bracket the diversity of solar system materials that we are likely to encounter, from undifferentiated to highly evolved. The 5-15 MHz radar is capable of probing more primitive bodies (e.g. comets or C-types) that may be available given other launch schedules. 5 MHz radar easily penetrates, with the required SNR , greater than 1 km of basalt (a good analog for Nyx). Basalt has a greater loss tangent than expected for most asteroids, although iron-rich M-types are probably not appropriate targets. 15 MHz radar penetrates the outer approximately 100 m of rocky 1 km asteroids and the deep interiors of comets. Laboratory studies of the most common NE0 materials expected (S-, C- and V-type meteorite analogs) will commence in 2005. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20100011079&hterms=Concept+hardware&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DConcept%2Bhardware','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20100011079&hterms=Concept+hardware&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DConcept%2Bhardware">Utilization of ISS to Develop and Test Operational Concepts and Hardware for Low-Gravity Terrestrial EVA</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Gast, Matthew A. 2010-01-01 NASA has considerable experience in two areas of Extravehicular Activities (EVA). The first can be defined as microgravity, orbital EVAs. This consists of everything done in low Earth orbit (LEO), from the early, proof of concept EVAs conducted during the Gemini program of the 1960s, to the complex International Space Station (ISS) assembly tasks of the first decade of the 21st century. The second area of expertise is comprised of those EVAs conducted on the lunar surface, under a gravitational force one-sixth that of Earth. This EVA expertise encapsulates two extremes - microgravity and Earthlike gravitation - but is insufficient as humans expand their exploration purview, most notably with respect to spacewalks conducted on very low-gravity bodies, such as near- Earth objects (NEO) and the moons of Mars. The operational and technical challenges of this category of EVA have yet to be significantly examined, and as such, only a small number of operational concepts have been proposed thus far. To ensure mission success, however, EVA techniques must be developed and vetted to allow the selection of operational concepts that can be utilized across an assortment of destinations whose physical characteristics vary. This paper examines the utilization of ISS-based EVAs to test operational concepts and hardware in preparation for a low-gravity terrestrial EVA. While the ISS cannot mimic some of the fundamental challenges of a low-gravity terrestrial EVA - such as rotation rate and surface composition - it may be the most effective test bed available. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMIN21C1745S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMIN21C1745S">Enhancing SAMOS Data Access in DOMS via a Neo4j Property Graph Database.</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Stallard, A. P.; Smith, S. R.; Elya, J. L. 2016-12-01 The Shipboard Automated Meteorological and Oceanographic System (SAMOS) initiative provides routine access to high-quality marine meteorological and near-surface oceanographic observations from research vessels. The Distributed Oceanographic Match-Up Service (DOMS) under development is a centralized service that allows researchers to easily match in situ and satellite oceanographic data from distributed sources to facilitate satellite calibration, validation, and retrieval algorithm development. The service currently uses Apache Solr as a backend search engine on each node in the distributed network. While Solr is a high-performance solution that facilitates creation and maintenance of indexed data, it is limited in the sense that its schema is fixed. The property graph model escapes this limitation by creating relationships between data objects. The authors will present the development of the SAMOS Neo4j property graph database including new search possibilities that take advantage of the property graph model, performance comparisons with Apache Solr, and a vision for graph databases as a storage tool for oceanographic data. The integration of the SAMOS Neo4j graph into DOMS will also be described. Currently, Neo4j contains spatial and temporal records from SAMOS which are modeled into a time tree and r-tree using Graph Aware and Spatial plugin tools for Neo4j. These extensions provide callable Java procedures within CYPHER (Neo4j's query language) that generate in-graph structures. Once generated, these structures can be queried using procedures from these libraries, or directly via CYPHER statements. Neo4j excels at performing relationship and path-based queries, which challenge relational-SQL databases because they require memory intensive joins due to the limitation of their design. Consider a user who wants to find records over several years, but only for specific months. If a traditional database only stores timestamps, this type of query would be complex and likely prohibitively slow. Using the time tree model, one can specify a path from the root to the data which restricts resolutions to certain timeframes (e.g., months). This query can be executed without joins, unions, or other compute-intensive operations, putting Neo4j at a computational advantage to the SQL database alternative. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.P33A1761K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.P33A1761K">Innovative Strategies for Asteroid Precursor Exploration</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Klaus, K.; Lawrence, S.; Elsperman, M. S.; Smith, D. B. 2011-12-01 Introduction: Our ambitions for space exploration have outpaced our ability to afford frequent visits to targets of interest. Launch costs and development times continue to increase for getting large space craft to deep space. This particularly affects workforce development and imperils opportunities for new development starts. The time has come to leverage technology advances (including advances in autonomous operation and propulsion technology) to reduce the cost and increase the flight rate of planetary missions, while actively developing a scientific and engineering workforce to achieve national space objectives. Background: As demonstrated by the 1994 Clementine mission, planetary exploration missions maximizing off-the-shelf components to obtain a focused set of measurement objectives can make meaningful contributions to advancing the frontiers of space exploration by achieving numerous science and exploration objectives. Near Earth Objects [NEOs] are interesting candidates for missions of this nature. While results from recent missions (i.e., Hayabusa, NEAR, Dawn) have dramatically increased our understanding of asteroids, important questions remain. For example, characterizing the properties of asteroid regolith is an important consideration for understanding telescopic observations of asteroids, as well as preparing for future asteroid human exploration. Spacecraft Concepts: There are many candidate target asteroids that are attainable with our concept. We envision a "mothership" carrying 2-3 nanosats to the target. The nanosats would serve as in-situ explorers. The spacecraft is notionally designed for launch on a Taurus II. Our study intends on validating the concept and our notional spacecraft design will be refined and presented. The current dry mass with nanosats is estimated to be 750kg. The 1999 JU3 mission concept is a rendezvous with a 950 kg of initial spacecraft mass, launched to a C3 of 4 km2/s2. Subtracting the spacecraft dry mass from the initial mass gives a propellant loading of 200 kg. The solution for this case required 115.3 kg of propellant, leaving a 42% propellant margin. Science Instrumentation: Key objectives of this notional asteroid explorer would include: (1) high-resolution surface topography; (2) characterization surface composition and mineralogy; (3) quantification of the radiation environment near an NEO; and (4) mechanical properties of surface, if a touchdown takes place. Each nanosat would notionally contain a stereo camera for navigation, an alpha proton x-ray spectrometer to make measurements of the surface chemistry, and a microscopic imaging system to characterize the particle size distribution of asteroid regolith; multiple nanosats would provided redundancy for the in-situ surface characterization phase of the mission and enable a rudimentary gravity map through radio signal tracking. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2391304','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2391304">Personality as a predictor of dietary quality in spouses during midlife</a> <a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Brummett, Beverly H.; Siegler, Ilene C.; Day, R. Sue; Costa, Paul T. 2008-01-01 Objective To examine the NEO personality inventory-revised (NEO-PI-R) as a predictor of dietary quality in married couples, with focus on associations among: 1) each participant’s personality as a predictor of their own dietary assessment, and 2) each participant’s personality as a predictor of their spouses’ dietary assessment. Method Participants were 850 couples from the University of North Carolina Alumni Heart Study (UNCAHS). NEO personality data was gathered during the baseline enrollment period from 1988–92. The dietary assessment was based on a modified version of the USDA Healthy Eating Index (MHEI) developed specifically for use in the UNCAHS; and data for calculating this measure were gathered from 1994–96. Analyses focused on examination of: 1) each participant’s NEO assessments with their own MHEI, and 2) each participant’s NEO assessments with their spouse’s MHEI. Results Openness was associated with self ratings of dietary quality for both wives’ (r = .28) and husband’s (r =.27). Wives’ Openness levels were also related to their spouses’ ratings of dietary quality (r =.22). The primary facets of Openness accounting for the domain level findings were O2:Aesthetics and O4:Actions. The remaining personality domains (Neuroticism, Extraversion, Agreeableness, and Conscientiousness) were not associated with self or spousal ratings of dietary quality (r’s −.10 – .01). Conclusion Openness is associated with healthy eating habits—findings that may bear on disease prevention during midlife. PMID:18400684 </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014DPS....4621311K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014DPS....4621311K">Synoptic Observations for Physical Characterization of Fast Rotator NEOs</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Kikwaya Eluo, Jean-Baptiste; Hergenrother, Carl W. 2014-11-01 NEOs can be studied not only dynamically, to learn about their impact hazard, but also physically, to establish various properties important both to better address their potential hazard and also to understand what they can tell us about the origin of the solar system and its ongoing processes.Taking advantage of the two-meter-class telescopes around Tucson, we plan to observe NEOs synoptically using telescopes at three different locations: VATT (Vatican Advanced Technology Telescope) at Mount Graham (longitude: -109.8719, latitude: 32.7016, elevation: 10469 feet), Bok 2.3 m at Kitt Peak (longitude: -111.6004, latitude: 31.9629, elevation: 6795 feet) and Kuiper 1.5-m at Mount Bigelow (longitude: -110.7345, latitude: 32.4165, elevation: 8235 feet). All three telescopes will aim simultaneously at the same object, each with a different instrument. The three telescopes will be part of the Arizona Robotic Telescope (ART) network, a University of Arizona initiative to provide near real-time observations of Target of Opportunity objects across the visible and near-infrared wavelengths. The VATT-4K optical imager mounted on the VATT has already been used for photometry. In the future we plan to utilize the BCSpec (Boller & Chivens Spectrograph) for visible spectroscopy on Bok 2.3 meter and a near-infrared instrument on Kuiper 1.5 meter. We report here the preliminary results of several NEOs whose rotation rate and color have been estimated using photometry with images recorded with VATT-4K. 2009 SQ104 has a rotation rate of 6.85+/- 0.03 h, 2014 AY28 has a rotation rate of 0.91 +/- 0.02 h, 2014 EC of 0.54 +/-0.04 h, 2014 FA44 of 3.45 +/- 0.05 h, and 2014 KS40 of 1.11 +/- 0.06 h. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006epsc.conf..435G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006epsc.conf..435G">To measure the chemical composition of a Near Earth Object</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Gasnault, 0.; Ball, A.; Biele, J.; D'Uston, C.; Forni, O.; Klingelhofer, G.; Maurice, S.; Ulamec, S. Introduction. Scenarios for a Near Earth Object (NEO) rendezvous mission were discussed recently in Europe. Such a mission would address scientific questions about the initial conditions and evolutionary history of the solar nebula, as well as mitigation considerations to prevent impact with the Earth. In our opinion the measurement of the elemental composition and the distribution of volatiles in the shallow sub-surface are two of the key observations to be conducted, either from an orbiter or a lander. These measurements are also valuable for documentation (landing site candidates and sample context). This report is limited to the chemical composition, but we assume that remote and/or in-situ observations of physical characteristics, interior, morphology, mineralogy, and organic compounds will also be made as essential complements to achieve the mission scientific objectives. Scientific Interest. The analysis of the bulk composition addresses three fundamental aspects of the scientific mission: (1) the formation of the asteroid or the comet; (2) the evolution of the object; (3) the relation between the parent body and collected meteorites on Earth. Classification of an asteroid/comet can be based on its global composition (abundances of Mg, Si, Fe, Al, Ca, etc. along with its mineralogy), which bears the signature of the feeding zone where it formed. For example the K/U and K/Th ratios seem to increase with distance from the Sun (decreasing temperature). The hydrogen content is another measurable to study the distribution of volatiles in the Solar System. The surface composition is also the result of the degree of evolution of the object and of the interactions with its environment. Building a compositional map of the major elements is necessary to identify and characterize the processes that influenced the asteroid along its history. Finally, knowing the chemical composition will obviously help to relate the parent 1 body to meteorites. Ideally the measurement of specific isotopes, including O, C and those produced by the exposure to the cosmic rays, such as 38 Ar or 21 Ne, can pinpoint to the family of meteorites, but such measurements are challenging with restricted resources. Instrument Payload Options. To define the most appropriate instrument(s) in terms of scientific return and technical constraints, various solutions have been studied. For the orbiter this includes an X-ray spectrometer with a solar monitor, and a gamma-ray spectrometer with a neutron sensor. For a lander, it has been demonstrated that an active X-ray spectrometer gives outstanding results for very low resources. If mass is available in the frame of an ambitious mission, one can consider active experiments such as a laser-induced breakdown spectrometer, a mass spectrometer (needing sample manipulation, a laser ablation system, or an ion source), or evolved gas analyzers. It is very difficult however to baseline the use of active experiments from the orbiter (very close fly-bys) such as those on board the Phobos missions. On the one hand the main constraints on the lander are related to the resources (mass, power, volume) and possibly the need for target contact/manipulation. On the other hand the difficulties from the orbiter are the sensitivity to prioritized chemical elements and the mapping resolution (e.g. of the order of 1/10 of the altitude for X-rays, and equivalent to the altitude for gamma-rays). Remote-sensing experiments have been evaluated from that perspective; It is possible to estimate the accumulation time needed to reach enough precision: of the order of 1 h for X-rays and several hours for gamma-rays above each pixel (defined by the spatial resolution, see above). In a classical orbital mission scenario these numbers translate into several weeks of observations (more than 1 month). Lessons learned from previous missions (Apollo, Lunar Prospector, NEAR, Mars Odyssey, SMART-1) are also taken into account: the difficulty to monitor the solar activity for the X-rays, the low signal to noise ratio for the gamma-rays. Previous experiments were successful when the ratio orbit-radius over body-radius was about 5-7 for X-rays and less than 2 for gamma-rays. All these points put strong constraints on the operations to measure properly the chemical composition of a NEO. 2 </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1915833N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1915833N">Constraining central Neo-Tethys Ocean reconstructions with mantle convection models</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Nerlich, Rainer; Colli, Lorenzo; Ghelichkhan, Siavash; Schuberth, Bernhard; Bunge, Hans-Peter 2017-04-01 A striking feature of the Indian Ocean is a distinct geoid low south of India, pointing to a regionally anomalous mantle density structure. Equally prominent are rapid plate convergence rate variations between India and SE Asia, particularly in Late Cretaceous/Paleocene times. Both observations are linked to the central Neo-Tethys Ocean subduction history, for which competing scenarios have been proposed. Here we evaluate three alternative reconstructions by assimilating their associated time-dependent velocity fields in global high-resolution geodynamic Earth models, allowing us to predict the resulting seismic mantle heterogeneity and geoid signal. Our analysis reveals that a geoid low similar to the one observed develops naturally when a long-lived back-arc basin south of Eurasia's paleomargin is assumed. A quantitative comparison to seismic tomography further supports this model. In contrast, reconstructions assuming a single northward dipping subduction zone along Eurasia's margin or models incorporating a temporary southward dipping intraoceanic subduction zone cannot sufficiently reproduce geoid and seismic observations. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoRL..43.9595N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoRL..43.9595N">Constraining central Neo-Tethys Ocean reconstructions with mantle convection models</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Nerlich, Rainer; Colli, Lorenzo; Ghelichkhan, Siavash; Schuberth, Bernhard; Bunge, Hans-Peter 2016-09-01 A striking feature of the Indian Ocean is a distinct geoid low south of India, pointing to a regionally anomalous mantle density structure. Equally prominent are rapid plate convergence rate variations between India and SE Asia, particularly in Late Cretaceous/Paleocene times. Both observations are linked to the central Neo-Tethys Ocean subduction history, for which competing scenarios have been proposed. Here we evaluate three alternative reconstructions by assimilating their associated time-dependent velocity fields in global high-resolution geodynamic Earth models, allowing us to predict the resulting seismic mantle heterogeneity and geoid signal. Our analysis reveals that a geoid low similar to the one observed develops naturally when a long-lived back-arc basin south of Eurasia's paleomargin is assumed. A quantitative comparison to seismic tomography further supports this model. In contrast, reconstructions assuming a single northward dipping subduction zone along Eurasia's margin or models incorporating a temporary southward dipping intraoceanic subduction zone cannot sufficiently reproduce geoid and seismic observations. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active">18</li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active">19</li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110010927','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110010927">Analogs and the BHP Risk Reduction Strategy for Future Spaceflight Missions</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Whitmire, Sandra; Leveton, Lauren 2011-01-01 In preparation for future exploration missions to distant destinations (e.g., Moon, Near Earth Objects (NEO), and Mars), the NASA Human Research Program s (HRP) Behavioral Health and Performance Element (BHP) conducts and supports research to address four human health risks: Risk of Behavioral Conditions; Risk of Psychiatric Conditions; Risk of Performance Decrements Due to Inadequate Cooperation, Coordination, Communication, and Psychosocial Adaptation within a Team; and Risk of Performance Errors due to Sleep Loss, Fatigue, Circadian Desynchronization, and Work Overload (HRP Science Management Plan, 2008). BHP Research, in collaboration with internal and external research investigators, as well as subject matter experts within NASA operations including flight surgeons, astronauts, and mission planners and others within the Mission Operations Directorate (MOD), identifies knowledge and technology gaps within each Risk. BHP Research subsequently manages and conducts research tasks to address and close the gaps, either through risk assessment and quantification, or the development of countermeasures and monitoring technologies. The resulting deliverables, in many instances, also support current Medical Operations and/or Mission Operations for the International Space Station (ISS). </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20130014116','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20130014116">Wells for In Situ Extraction of Volatiles from Regolith (WIEVR)</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Walton, Otis R. 2013-01-01 A document discusses WIEVRs, a means to extract water ice more efficiently than previous approaches. This water may exist in subsurface deposits on the Moon, in many NEOs (Near- Earth Objects), and on Mars. The WIEVR approach utilizes heat from the Sun to vaporize subsurface ice; the water (or other volatile) vapor is transported to a surface collection vessel where it is condensed (and collected). The method does not involve mining and extracting regolith before removing the frozen volatiles, so it uses less energy and is less costly than approaches that require mining of regolith. The only drilling required for establishing the WIEVR collection/recovery system is a well-bore drill hole. In its simplest form, the WIEVRs will function without pumps, compressors, or other gas-moving equipment, relying instead on diffusive transport and thermally induced convection of the vaporized volatiles for transport to the collection location(s). These volatile extraction wells could represent a significant advance in extraction efficiency for recovery of frozen volatiles in subsurface deposits on the Moon, Mars, or other extraterrestrial bodies. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110012973','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110012973">Human System Drivers for Exploration Missions</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Kundrot, Craig E.; Steinberg, Susan; Charles, John B. 2010-01-01 Evaluation of DRM4 in terms of the human system includes the ability to meet NASA standards, the inclusion of the human system in the design trade space, preparation for future missions and consideration of a robotic precursor mission. Ensuring both the safety and the performance capability of the human system depends upon satisfying NASA Space Flight Human System Standards.1 These standards in turn drive the development of program-specific requirements for Near-earth Object (NEO) missions. In evaluating DRM4 in terms of these human system standards, the currently existing risk models, technologies and biological countermeasures were used. A summary of this evaluation is provided below in a structure that supports a mission architecture planning activities. 1. Unacceptable Level of Risk The duration of the DRM4 mission leads to an unacceptable level of risk for two aspects of human system health: A. The permissible exposure limit for space flight radiation exposure (a human system standard) would be exceeded by DRM4. B. The risk of visual alterations and abnormally high intracranial pressure would be too high. 1 </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JPhCS.304a2056K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JPhCS.304a2056K">Acute toxicity of virgin and used engine oil enriched with copper nano particles in the earthworm</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Khodabandeh, M.; Koohi, M. K.; Roshani, A.; Shahroziyan, E.; Badri, B.; Pourfallah, A.; Shams, Gh; Hobbenaghi, R.; Sadeghi-Hashjin, G. 2011-07-01 In spite of development of nanotechnology and creation of new opportunities for industry, new applications and products initiated by this technology may cause harmful effects on human health and environment. Unfortunately, there is no sufficient information on the harmful effects caused by application of some nano materials; the current knowledge in this field is limited solely to the nano particles but not the final products. Nano cupper particles, as one of the common materials produced in industrial scale is widely used as additives into engine oil to reduce friction and improve lubrication. However, the difference between the effects of virgin and used conventional engine oil (CEO) and the engine oil containing cupper nano particles (NEO) on the environment is not known. Earthworm, as a one of the species which could live and survive in different sorts of earth and has a certain role in protecting the soil structure and fertility, was used in this experiment. In accordance with the recommended method of OECD.1984, Filter Paper test in 24 and 48 h based on 8 concentrations in the range of 3×10-3 - 24×10-3 ml/cm2 and Artificial Soil test in 7 and 14 days based on 7 concentrations in the range of 0.1 mg/kg - 100 g/kg were carried out to study earthworms in terms of lifetime (LC50), morphology and pathology. It was shown that the 48 h LC50 for virgin CEO, virgin NEO, used CEO(8000 km) and used NEO (8000 km) were 6×10-3, 23×10-3, 24×10-3 and 16×10-3 ml/cm2 respectively. Furthermore, 14-day LC50 in artificial soil for all cases were above 100 g/kg. It is concluded that virgin CEO is more toxic than virgin NEO. Meanwhile, the CEO shows significant reduction in toxicity after consumption and the used NEO shows more toxicity in comparison to virgin product. It seems that more investigations on the effects of final products specifically after consumption is necessary because the products after consumption have the most contact with environment and subsequently human health. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005Icar..179...63B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005Icar..179...63B">Linking the collisional history of the main asteroid belt to its dynamical excitation and depletion</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Bottke, William F.; Durda, Daniel D.; Nesvorný, David; Jedicke, Robert; Morbidelli, Alessandro; Vokrouhlický, David; Levison, Harold F. 2005-12-01 The main belt is believed to have originally contained an Earth mass or more of material, enough to allow the asteroids to accrete on relatively short timescales. The present-day main belt, however, only contains ˜5×10 Earth masses. Numerical simulations suggest that this mass loss can be explained by the dynamical depletion of main belt material via gravitational perturbations from planetary embryos and a newly-formed Jupiter. To explore this scenario, we combined dynamical results from Petit et al. [Petit, J. Morbidelli, A., Chambers, J., 2001. The primordial excitation and clearing of the asteroid belt. Icarus 153, 338-347] with a collisional evolution code capable of tracking how the main belt undergoes comminution and dynamical depletion over 4.6 Gyr [Bottke, W.F., Durda, D., Nesvorny, D., Jedicke, R., Morbidelli, A., Vokrouhlický, D., Levison, H., 2005. The fossilized size distribution of the main asteroid belt. Icarus 175, 111-140]. Our results were constrained by the main belt's size-frequency distribution, the number of asteroid families produced by disruption events from diameter D>100 km parent bodies over the last 3-4 Gyr, the presence of a single large impact crater on Vesta's intact basaltic crust, and the relatively constant lunar and terrestrial impactor flux over the last 3 Gyr. We used our model to set limits on the initial size of the main belt as well as Jupiter's formation time. We find the most likely formation time for Jupiter was 3.3±2.6 Myr after the onset of fragmentation in the main belt. These results are consistent with the estimated mean disk lifetime of 3 Myr predicted by Haisch et al. [Haisch, K.E., Lada, E.A., Lada, C.J., 2001. Disk frequencies and lifetimes in young clusters. Astrophys. J. 553, L153-L156]. The post-accretion main belt population, in the form of diameter D≲1000 km planetesimals, was likely to have been 160±40 times the current main belt's mass. This corresponds to 0.06-0.1 Earth masses, only a small fraction of the total mass thought to have existed in the main belt zone during planet formation. The remaining mass was most likely taken up by planetary embryos formed in the same region. Our results suggest that numerous D>200 km planetesimals disrupted early in Solar System history, but only a small fraction of their fragments survived the dynamical depletion event described above. We believe this may explain the limited presence of iron-rich M-type, olivine-rich A-type, and non-Vesta V-type asteroids in the main belt today. The collisional lifetimes determined for main belt asteroids agree with the cosmic ray exposure ages of stony meteorites and are consistent with the limited collisional evolution detected among large Koronis family members. Using the same model, we investigated the near-Earth object (NEO) population. We show the shape of the NEO size distribution is a reflection of the main belt population, with main belt asteroids driven to resonances by Yarkovsky thermal forces. We used our model of the NEO population over the last 3 Gyr, which is consistent with the current population determined by telescopic and satellite data, to explore whether the majority of small craters ( D<0.1-1 km) formed on Mercury, the Moon, and Mars were produced by primary impacts or by secondary impacts generated by ejecta from large craters. Our results suggest that most small craters formed on these worlds were a by-product of secondary rather than primary impacts. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26280473','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26280473">Neosaxitoxin in Rat Sciatic Block: Improved Therapeutic Index Using Combinations with Bupivacaine, with and without Epinephrine.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Templin, Jay S; Wylie, Matthew C; Kim, Joseph D; Kurgansky, Katherine E; Gorski, Grzegorz; Kheir, John; Zurakowski, David; Corfas, Gabriel; Berde, Charles 2015-10-01 Neosaxitoxin (NeoSTX) is a site-1 sodium channel blocker undergoing clinical trials as a prolonged-duration local anesthetic. Rat sciatic block and intravenous infusion models were used to assess efficacy and local and systemic toxicities for NeoSTX in saline (NeoSTX-Saline), bupivacaine (Bup), and their combination (NeoSTX-Bup). Exploratory studies evaluated the effects of addition of epinephrine to NeoSTX-Bup (NeoSTX-Bup-Epi). Rats received percutaneous sciatic blocks with escalating doses of NeoSTX-Saline or NeoSTX-Bup. Sensory-nocifensive block was assessed using modified hotplate and Von Frey filaments. Motor-proprioceptive function was assessed by extensor postural thrust. Nerves were examined histologically after 7 days and scored on the Estebe-Myers scale. Median lethal dose was estimated for NeoSTX-Saline and in combinations. Accidental intravenous overdose was simulated in isoflurane-anesthetized, spontaneously breathing rats receiving NeoSTX-Saline (n = 6), Bup (n = 7), or NeoSTX-Bup (n = 13), with respiratory, hemodynamic, and electrocardiographic endpoints. Additional groups received blocks with NeoSTX-Bup-Epi (n = 80). Investigators were blinded for behavioral and histologic studies. NeoSTX-Bup produced more prolonged sensory and motor block compared with NeoSTX-Saline or Bup. NeoSTX-Bup-Epi further prolonged median time to near-complete recovery for 3 μg/kg NeoSTX-Bup (hotplate: 48 vs. 6 h, P < 0.001). With sciatic injections, addition of Bup did not worsen the systemic toxicity (median lethal dose) compared with NeoSTX-Saline. Intravenous NeoSTX-Saline infusion had significantly longer times to apnea, first arrhythmia, and asystole compared with Bup (P < 0.001 for each). Histologic injury scores overall were low for all groups, with median scores of 0 (interquartile range, 0 to 0) on a 5-point scale. NeoSTX-Bup and NeoSTX-Bup-Epi hold promise for prolonged-duration local anesthesia. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4653389','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4653389">cyNeo4j: connecting Neo4j and Cytoscape</a> <a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Summer, Georg; Kelder, Thomas; Ono, Keiichiro; Radonjic, Marijana; Heymans, Stephane; Demchak, Barry 2015-01-01 Summary: We developed cyNeo4j, a Cytoscape App to link Cytoscape and Neo4j databases to utilize the performance and storage capacities Neo4j offers. We implemented a Neo4j NetworkAnalyzer, ForceAtlas2 layout and Cypher component to demonstrate the possibilities a distributed setup of Cytoscape and Neo4j have. Availability and implementation: The app is available from the Cytoscape App Store at http://apps.cytoscape.org/apps/cyneo4j, the Neo4j plugins at www.github.com/gsummer/cyneo4j-parent and the community and commercial editions of Neo4j can be found at http://www.neo4j.com. Contact: georg.summer@gmail.com PMID:26272981 </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMIN11A3597L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMIN11A3597L">Using Enabling Technologies to Facilitate the Comparison of Satellite Observations with the Model Forecasts for Hurricane Study</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Li, P.; Knosp, B.; Hristova-Veleva, S. M.; Niamsuwan, N.; Johnson, M. P.; Shen, T. P. J.; Tanelli, S.; Turk, J.; Vu, Q. A. 2014-12-01 Due to their complexity and volume, the satellite data are underutilized in today's hurricane research and operations. To better utilize these data, we developed the JPL Tropical Cyclone Information System (TCIS) - an Interactive Data Portal providing fusion between Near-Real-Time satellite observations and model forecasts to facilitate model evaluation and improvement. We have collected satellite observations and model forecasts in the Atlantic Basin and the East Pacific for the hurricane seasons since 2010 and supported the NASA Airborne Campaigns for Hurricane Study such as the Genesis and Rapid Intensification Processes (GRIP) in 2010 and the Hurricane and Severe Storm Sentinel (HS3) from 2012 to 2014. To enable the direct inter-comparisons of the satellite observations and the model forecasts, the TCIS was integrated with the NASA Earth Observing System Simulator Suite (NEOS3) to produce synthetic observations (e.g. simulated passive microwave brightness temperatures) from a number of operational hurricane forecast models (HWRF and GFS). An automated process was developed to trigger NEOS3 simulations via web services given the location and time of satellite observations, monitor the progress of the NEOS3 simulations, display the synthetic observation and ingest them into the TCIS database when they are done. In addition, three analysis tools, the joint PDF analysis of the brightness temperatures, ARCHER for finding the storm-center and the storm organization and the Wave Number Analysis tool for storm asymmetry and morphology analysis were integrated into TCIS to provide statistical and structural analysis on both observed and synthetic data. Interactive tools were built in the TCIS visualization system to allow the spatial and temporal selections of the datasets, the invocation of the tools with user specified parameters, and the display and the delivery of the results. In this presentation, we will describe the key enabling technologies behind the design of the TCIS interactive data portal and analysis tools, including the spatial database technology for the representation and query of the level 2 satellite data, the automatic process flow using web services, the interactive user interface using the Google Earth API, and a common and expandable Python wrapper to invoke the analysis tools. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22826461','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22826461">Patterns of molecular evolution of an avian neo-sex chromosome.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Pala, Irene; Hasselquist, Dennis; Bensch, Staffan; Hansson, Bengt 2012-12-01 Newer parts of sex chromosomes, neo-sex chromosomes, offer unique possibilities for studying gene degeneration and sequence evolution in response to loss of recombination and population size decrease. We have recently described a neo-sex chromosome system in Sylvioidea passerines that has resulted from a fusion between the first half (10 Mb) of chromosome 4a and the ancestral sex chromosomes. In this study, we report the results of molecular analyses of neo-Z and neo-W gametologs and intronic parts of neo-Z and autosomal genes on the second half of chromosome 4a in three species within different Sylvioidea lineages (Acrocephalidea, Timaliidae, and Alaudidae). In line with hypotheses of neo-sex chromosome evolution, we observe 1) lower genetic diversity of neo-Z genes compared with autosomal genes, 2) moderate synonymous and weak nonsynonymous sequence divergence between neo-Z and neo-W gametologs, and 3) lower GC content on neo-W than neo-Z gametologs. Phylogenetic reconstruction of eight neo-Z and neo-W gametologs suggests that recombination continued after the split of Alaudidae from the rest of the Sylvioidea lineages (i.e., after ~42.2 Ma) and with some exceptions also after the split of Acrocephalidea and Timaliidae (i.e., after ~39.4 Ma). The Sylvioidea neo-sex chromosome shares classical evolutionary features with the ancestral sex chromosomes but, as expected from its more recent origin, shows weaker divergence between gametologs. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EPSC...11..137B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EPSC...11..137B">NEOShield-2 project: Phase effects in NEA visible spectra</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Barucci, M. A.; Perna, D.; Belskaya, I.; Popescu, M.; Fornasier, S.; Doressoundiram, A.; Lantz, C.; Merlin, F.; Fulchignoni, M. 2017-09-01 One of the main objectives of the NEOShield-2 project, funded by European Commission (2015-2017) in the framework of the EU H2020 program, is to provide physical and compositional characterization of a large number of NEOs in the hundred-meter size range. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=culture+AND+personality&pg=7&id=EJ849558','ERIC'); return false;" href="https://eric.ed.gov/?q=culture+AND+personality&pg=7&id=EJ849558">Assessing the Universal Structure of Personality in Early Adolescence: The NEO-PI-R and NEO-PI-3 in 24 Cultures</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> De Fruyt, Filip; De Bolle, Marleen; McCrae, Robert R.; Terracciano, Antonio; Costa, Paul T., Jr. 2009-01-01 The structure and psychometric characteristics of the NEO Personality Inventory-3 (NEO-PI-3), a more readable version of the Revised NEO Personality Inventory (NEO-PI-R), are examined and compared with NEO-PI-R characteristics using data from college student observer ratings of 5,109 adolescents aged 12 to 17 years from 24 cultures. Replacement… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26297314','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26297314">Exploring the influence of context in a community-based facilitation intervention focusing on neonatal health and survival in Vietnam: a qualitative study.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Duong, Duc M; Bergström, Anna; Wallin, Lars; Bui, Ha T T; Eriksson, Leif; Eldh, Ann Catrine 2015-08-22 In the Neonatal health - Knowledge into Practice (NeoKIP) trial in Vietnam, local stakeholder groups, supported by trained laywomen acting as facilitators, promoted knowledge translation (KT) resulting in decreased neonatal mortality. In general, as well as in the community-based NeoKIP trial, there is a need to further understand how context influences KT interventions in low- and middle-income countries (LMICs). Thus, the objective of this study was to explore the influence of context on the facilitation process in the NeoKIP intervention. A secondary content analysis was performed on 16 Focus Group Discussions with facilitators and participants of the stakeholder groups, applying an inductive approach to the content on context through naïve understanding and structured analysis. The three main-categories of context found to influence the facilitation process in the NeoKIP intervention were: (1) Support and collaboration of local authorities and other communal stakeholders; (2) Incentives to, and motivation of, participants; and (3) Low health care coverage and utilization. In particular, the role of local authorities in a KT intervention was recognized as important. Also, while project participants expected financial incentives, non-financial benefits such as individual learning were considered to balance the lack of reimbursement in the NeoKIP intervention. Further, project participants recognized the need to acknowledge the needs of disadvantaged groups. This study provides insight for further understanding of the influence of contextual aspects to improve effects of a KT intervention in Vietnam. We suggest that future KT interventions should apply strategies to improve local authorities' engagement, to identify and communicate non-financial incentives, and to make disadvantaged groups a priority. Further studies to evaluate the contextual aspects in KT interventions in LMICs are also needed. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA358303','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA358303">Improved Second-Generation 3-D Volumetric Display System. Revision 2</a> <a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a> 1998-10-01 computer control, uses infrared lasers to address points within a rare-earth-infused solid glass cube. Already, simple animated computer-generated images...Volumetric Display System permits images to be displayed in a three- dimensional format that can be observed without the use of special glasses . Its...MM 120 nm 60 mm nI POLARIZING I $-"• -’’""BEAMSPLI’i-ER ) 4P40-MHz 50-MHz BW PLRZN i TeO2 MODULATORS TeO2 DEFLECTORS Figure 1-4. NEOS four-channel </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170011337','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170011337">Autonomous Mission Operations</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Frank, Jeremy; Spirkovska, Lilijana; McCann, Rob; Wang, Lui; Pohlkamp, Kara; Morin, Lee 2012-01-01 NASA's Advanced Exploration Systems Autonomous Mission Operations (AMO) project conducted an empirical investigation of the impact of time-delay on todays mission operations, and of the effect of processes and mission support tools designed to mitigate time-delay related impacts. Mission operation scenarios were designed for NASA's Deep Space Habitat (DSH), an analog spacecraft habitat, covering a range of activities including nominal objectives, DSH system failures, and crew medical emergencies. The scenarios were simulated at time-delay values representative of Lunar (1.2-5 sec), Near Earth Object (NEO) (50 sec) and Mars (300 sec) missions. Each combination of operational scenario and time-delay was tested in a Baseline configuration, designed to reflect present-day operations of the International Space Station, and a Mitigation configuration in which a variety of software tools, information displays, and crew-ground communications protocols were employed to assist both crews and Flight Control Team (FCT) members with the long-delay conditions. Preliminary findings indicate: 1) Workload of both crew members and FCT members generally increased along with increasing time delay. 2) Advanced procedure execution viewers, caution and warning tools, and communications protocols such as text messaging decreased the workload of both flight controllers and crew, and decreased the difficulty of coordinating activities. 3) Whereas crew workload ratings increased between 50 sec and 300 sec of time-delay in the Baseline configuration, workload ratings decreased (or remained flat) in the Mitigation configuration. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014acm..conf..353M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014acm..conf..353M">ESA NEOCC effort to eliminate high Palermo Scale virtual impactors</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Micheli, M.; Koschny, D.; Hainaut, O.; Bernardi, F. 2014-07-01 At the moment of this writing about 4 % of the known near-Earth objects are known to have at least one future close approach scenario with a non-negligible collision probability within the next century, as routinely computed by the NEODyS and Sentry systems. The most straightforward way to improve the knowledge of the future dynamics of an NEO in order to exclude (or possibly confirm) some of these possible future impact is to obtain additional astrometric observations of the object as soon as it becomes observable again. In particular, since a large fraction (>98 %) of the known objects currently recognized as possible future impactors have been observed during a single opposition, this usually corresponds to obtaining a new set of observations during a second opposition, a so called ''recovery''. However, in some cases the future observability windows for the target after the discovery apparition may be very limited, either because the object is intrinsically small (and therefore requires a very close and consequently rare approach to become observable) or because its orbital dynamic prevents the observability from the ground for a long timespan (as in the case of quasi-resonant objects with a long synodic period). When this happens, the only short-term way to clarify an impact scenario is to look toward the past, and investigate the possibility that unrecognized detections of the object are already present in the databases of old astronomical images, which are often archived by professional telescopes and made available to the community a few months to years after they are exposed. We will here present an effort lead by the newly formed ESA NEO Coordination Centre (NEOCC) in Frascati to pursue both these avenues with the intent of improving the orbital knowledge of the highest-rated possible impactors, as defined by the Palermo Technical Impact Hazard Scale (PS in the following). As an example of our ongoing observational activities, we will first present our recovery observations of a few very faint high-PS objects, and the follow-up observations of recently discovered objects during the outgoing phase of their apparition, down to magnitude 25 or so. Most of these observations were obtained within an accepted DDT proposal of an ESA/ESO team, which gives us access on short notice to the observational capabilities of the 8.2 meter Very Large Telescope at Cerro Paranal, Chile. The instrument has been used to successfully detect targets fainter than V=25, and provide high-accuracy astrometry which in most cases has been sufficient to remove the impact solutions from the allowed future dynamics of the object. As a main focus of our activities at the ESA NEOCC we are also actively soliciting observations of NEOs by other worldwide observers which are known to have access to the most appropriate facilities for each target (in terms of telescope aperture, camera FoV and/or geographic location). We will also quickly summarize the results of some of these activities. In the second part of this contribution, we will present the result of a focused precovery effort by our team, which led to the identification, measurement and submission of previously unrecognized archival detections of possible impactors, most of which scored particularly high in the PS ranking, but would nevertheless have been unobservable for the imminent future. We will discuss a couple of interesting cases which could be entirely excluded as a risk thanks to the addition of faint detections we located in data from the Canada- France-Hawaii Telescope (CFHT), and an interesting case of a ''chain of precoveries'' where a first short-arc precovery allowed for the identification of additional observations obtained more than a decade earlier, which in turn lead to the elimination of the impact risk from that object. We will also discuss how a real time access to the data of current surveys like Pan-STARRS can allow almost immediate precovery observations of recently discovered possible impactors, allowing to clarify the impact probability within days from the discovery, and thus saving most of the observational effort often necessary to provide adequate follow-up to recent discoveries. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29087223','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29087223">Using Item Response Theory to Develop a 60-Item Representation of the NEO PI-R Using the International Personality Item Pool: Development of the IPIP-NEO-60.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Maples-Keller, Jessica L; Williamson, Rachel L; Sleep, Chelsea E; Carter, Nathan T; Campbell, W Keith; Miller, Joshua D 2017-10-31 Given advantages of freely available and modifiable measures, an increase in the use of measures developed from the International Personality Item Pool (IPIP), including the 300-item representation of the Revised NEO Personality Inventory (NEO PI-R; Costa & McCrae, 1992a ) has occurred. The focus of this study was to use item response theory to develop a 60-item, IPIP-based measure of the Five-Factor Model (FFM) that provides equal representation of the FFM facets and to test the reliability and convergent and criterion validity of this measure compared to the NEO Five Factor Inventory (NEO-FFI). In an undergraduate sample (n = 359), scores from the NEO-FFI and IPIP-NEO-60 demonstrated good reliability and convergent validity with the NEO PI-R and IPIP-NEO-300. Additionally, across criterion variables in the undergraduate sample as well as a community-based sample (n = 757), the NEO-FFI and IPIP-NEO-60 demonstrated similar nomological networks across a wide range of external variables (r ICC = .96). Finally, as expected, in an MTurk sample the IPIP-NEO-60 demonstrated advantages over the Big Five Inventory-2 (Soto & John, 2017 ; n = 342) with regard to the Agreeableness domain content. The results suggest strong reliability and validity of the IPIP-NEO-60 scores. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=kantian+AND+theory&pg=4&id=EJ546656','ERIC'); return false;" href="https://eric.ed.gov/?q=kantian+AND+theory&pg=4&id=EJ546656">Culture/Self as Subject, Object, and Process.</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Dorn, Charles M. 1996-01-01 Proposes an aesthetic philosophy concerning public art and art education that is based on neo-Kantian principles. This philosophy advocates an art that inspires and educates and is a valuable presence in individuals' lives. Contrasts this with art that is politically motivated and prone to "cultural victimization." (MJP) </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=object+AND+permanence&pg=7&id=EJ549505','ERIC'); return false;" href="https://eric.ed.gov/?q=object+AND+permanence&pg=7&id=EJ549505">The Object Permanence Fallacy.</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Greenberg, Daniel E. 1996-01-01 Developmentalists have overlooked the problem of the real impermanence of things. Though the metaphor of impermanence is central to Piagetian and neo-nativist accounts of representation, the development of the understanding of impermanence is unstudied. This article proposes that the development of the concept of impermanence is distinct from the… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014acm..conf...65B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014acm..conf...65B">Radar investigations of near-Earth asteroids at Arecibo and Goldstone</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Brozovic, M.; Nolan, M.; Benner, L.; Busch, M.; Howell, E.; Taylor, P.; Springmann, A.; Giorgini, J.; Margot, J.; Magri, C.; Sheppard, M.; Naidu, S. 2014-07-01 Radar observations are a powerful technique to study near-Earth asteroids (NEAs). The Arecibo and Goldstone planetary radars can provide delay-Doppler images that can directly resolve surface features such as concavities, hills, ridges, and boulders. Goldstone's 3.75-m resolution capability is invaluable when attempting to image NEAs with diameters smaller than 50 m. To date, over 430 near-Earth asteroids and 136 main-belt asteroids have been observed with radar. 80 % of the radar-detected NEAs have been observed within the last 10 years. The radar detection rate in the last three years has tripled relative to the average in the previous decade due to an increase in funding and greater scheduling flexibility. Currently, ˜400 observing hours per year at Goldstone and ˜600 observing hours per year at Arecibo are devoted to observing asteroids. We strive to observe all strong and moderately strong imaging targets, Yarkovsky drift candidates, NEOWISE targets, asteroids with very low perihelia that can be used to measure solar oblateness, and as many other detectable asteroids as resources allow. We also regularly attempt to observe any asteroid that is flagged by the Near-Earth Object Human Spaceflight Accessible Targets Study (NHATS) list (http://neo.jpl.nasa.gov/nhats/). To date, we have observed more than 60 NHATS objects at Arecibo and Goldstone. In the past three years, ˜1/3 of the detected asteroids were targets of opportunity (TOOs), some of which we observed within 24 h from when the discoveries were announced. Many TOOs are small, rapidly moving objects that are detectable by radar only within few lunar distances. Radar astrometry is particularly important for these asteroids because they are too faint to be followed for long with optical telescopes. A radar-range measurement often secures their orbit for decades or centuries, where otherwise the object would be lost and require rediscovery. In one of the extreme cases, two delay and two Doppler measurements from Goldstone prevented a newly discovered potentially hazardous asteroid (PHA) 2014 CU_{13} from being lost. The measurements also extended its Earth-encounter predictability by 1000 years. Radar observations of objects that are closer than ˜4 lunar distances (˜10.3 seconds RTT, round-trip-time for signal) previously required coordination between two stations (one for transmit and one for receive) due to the short RTT and need to physically switch between transmit and receive configurations. However, the switching process has been accelerated and recent observations of 2013 XY_8 have shown that Goldstone can now conduct monostatic observations with RTTs of ˜5 seconds. This provides much stronger signal-to-noise ratios for very close targets. With the rapidly growing number of radar detections, some population trends are emerging. The latest statistics show that the fraction of contact binaries has grown to ˜14 % and is now comparable to that of true binaries in the NEA population with diameters larger than 200 m. We are also starting to capture what may be the tail ends of certain sub-populations. For example, we have found two very small binary systems, 2003 SS_{84} and 2004 FG_{11}, that have primaries < 200 m in diameter; we have also found that 2005 AY_{28} and 2013 JR_{28} are contact binaries in the same size range. These objects are at the boundary between gravitationally bound ''rubble piles'' and strength-dominated, possibly monolithic objects. The NEAs are a very diverse population, in which we continue to discover unusual objects. It is difficult to anticipate what the future radar observations may uncover, but surprises are likely. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA332344','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA332344">A Mouse Model for the Cloning of a Tumor Suppressor Gene Mutated in Sporadic Breast Cancer</a> <a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a> 1997-07-01 deletion. Figure 1 COLJA2 c-MET CFTR m ch -// 6’/- Cola-2 c-Met Cftr Ob D6MIT138 Objective 2. Analysis of the deletion allele of mouse chromosome 6...I- I I I I ; I ............. 2.88Kb - cftrexon3 % 2I IIO i M I I - hprt lox PGK-Neo-bGHpA 2 z I I III "’I I I bGHpA-Neo-PGK tox hprt 4.6 Kb 18.2...antibiotics. 16 Dr. Henry B. Skinner Figure 6 mch 6 0-0- 7 / D6MITIXX Cfbr Cre + HAT Selection m ch 6 0"-/, D6MITIXX-Cftr However, HAT resistant colonies </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active">19</li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active">20</li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=Obligations+AND+contract&pg=2&id=EJ942231','ERIC'); return false;" href="https://eric.ed.gov/?q=Obligations+AND+contract&pg=2&id=EJ942231">"Flexibility", Community and Making Parents Responsible</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> McGowan, Wayne S. 2005-01-01 This article draws on Foucault's concept of governmentality to explore how recent political moves to legalise "flexibility" mobilises education authorities to make "community" a technical means of achieving the political objective of schooling the child. I argue that "flexibility" in this sense is a neo-liberal strategy that shifts relations… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=personality+AND+traits&pg=7&id=EJ1012869','ERIC'); return false;" href="https://eric.ed.gov/?q=personality+AND+traits&pg=7&id=EJ1012869">Distinct ADHD Symptom Clusters Differentially Associated with Personality Traits</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> McKinney, Ashley A.; Canu, Will H.; Schneider, H. G. 2013-01-01 Objective: ADHD has been linked to various constructs, yet there is a lack of focus on how its symptom clusters differentially associate with personality, which this study addresses. Method: The current study examines the relationship between impulsive and inattentive ADHD traits and personality, indexed by the Revised NEO Personality Inventory… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=role+AND+overload&pg=2&id=EJ987816','ERIC'); return false;" href="https://eric.ed.gov/?q=role+AND+overload&pg=2&id=EJ987816">Personality Traits and Occupational Stress among Chinese Academics</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Zhang, Li-Fang 2012-01-01 The primary objective of this study was to examine the predictive power of personality traits for occupational stress among Chinese university academics. Two hundred and forty-six participants responded to the NEO Five-Factor Inventory and the Occupational Stress Inventory-Revised. Results indicated that the strongest predictor for occupational… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25990848','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25990848">An examination of retention factors among registered practical nurses in north-eastern Ontario, Canada.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Nowrouzi, B; Rukholm, E; Larivière, M; Carter, L; Koren, I; Mian, O 2015-01-01 Literature from the past two decades has presented an insufficient amount of research conducted on the nursing practice environments of registered practical nurses (RPNs). The objective of this article was to investigate the barriers and facilitators to sustaining the nursing workforce in north-eastern Ontario (NEO), Canada. In particular, retention factors for RPNs were examined. This cross-sectional research used a self-administered questionnaire. Home addresses of RPNs working in NEO were obtained from the College of Nurses of Ontario (CNO). Following a modified Dillman approach with two mail-outs, survey packages were sent to a random sample of RPNs (N=1337) within the NEO region. Logistic regression analyses were used to determine intent to stay (ITS) in relation to the following factor categories: demographic, and job and career satisfaction. Completed questionnaires were received from 506 respondents (37.8% response rate). The likeliness of ITS in the RPNs' current position for the next 5 years among nurses aged 46-56 years were greater than RPNs in the other age groups. Furthermore, the lifestyle of NEO, internal staff development, working in nursing for 14-22.5 years, and working less than 1 hour of overtime per week were factors associated with the intention to stay. Having an understanding of the work environment may contribute to recruitment and retention strategy development. The results of this study may assist with addressing the nursing shortage in rural and northern areas through improved retention strategies of RPNs. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=jobs+AND+orientation&pg=5&id=EJ931477','ERIC'); return false;" href="https://eric.ed.gov/?q=jobs+AND+orientation&pg=5&id=EJ931477">Assessing New Employee Orientation Programs</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Acevedo, Jose M.; Yancey, George B. 2011-01-01 Purpose: This paper aims to examine the importance of new employee orientation (NEO) programs, the quality of typical NEOs, and how to improve NEOs. Design/methodology/approach: The paper provides a viewpoint of the importance of new employee orientation programs, the quality of typical NEOs, and how to improve NEOs. Findings: Although western… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19419953','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19419953">Assessing the universal structure of personality in early adolescence: The NEO-PI-R and NEO-PI-3 in 24 cultures.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> De Fruyt, Filip; De Bolle, Marleen; McCrae, Robert R; Terracciano, Antonio; Costa, Paul T 2009-09-01 The structure and psychometric characteristics of the NEO Personality Inventory-3 (NEO-PI-3), a more readable version of the Revised NEO Personality Inventory (NEO-PI-R), are examined and compared with NEO-PI-R characteristics using data from college student observer ratings of 5,109 adolescents aged 12 to 17 years from 24 cultures. Replacement items in the PI-3 showed on average stronger item-total correlations and slightly improved facet reliabilities compared with the NEO-PI-R in both English- and non-English-speaking samples. NEO-PI-3 replacement items did not substantially affect scale means compared with the original scales. Analyses across and within cultures confirmed the intended factor structure of both versions when used to describe young adolescents. The authors discuss implications of these cross-cultural findings for the advancement of studies in adolescence and personality development across the lifespan. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24932643','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24932643">A test of the International Personality Item Pool representation of the Revised NEO Personality Inventory and development of a 120-item IPIP-based measure of the five-factor model.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Maples, Jessica L; Guan, Li; Carter, Nathan T; Miller, Joshua D 2014-12-01 There has been a substantial increase in the use of personality assessment measures constructed using items from the International Personality Item Pool (IPIP) such as the 300-item IPIP-NEO (Goldberg, 1999), a representation of the Revised NEO Personality Inventory (NEO PI-R; Costa & McCrae, 1992). The IPIP-NEO is free to use and can be modified to accommodate its users' needs. Despite the substantial interest in this measure, there is still a dearth of data demonstrating its convergence with the NEO PI-R. The present study represents an investigation of the reliability and validity of scores on the IPIP-NEO. Additionally, we used item response theory (IRT) methodology to create a 120-item version of the IPIP-NEO. Using an undergraduate sample (n = 359), we examined the reliability, as well as the convergent and criterion validity, of scores from the 300-item IPIP-NEO, a previously constructed 120-item version of the IPIP-NEO (Johnson, 2011), and the newly created IRT-based IPIP-120 in comparison to the NEO PI-R across a range of outcomes. Scores from all 3 IPIP measures demonstrated strong reliability and convergence with the NEO PI-R and a high degree of similarity with regard to their correlational profiles across the criterion variables (rICC = .983, .972, and .976, respectively). The replicability of these findings was then tested in a community sample (n = 757), and the results closely mirrored the findings from Sample 1. These results provide support for the use of the IPIP-NEO and both 120-item IPIP-NEO measures as assessment tools for measurement of the five-factor model. (c) 2014 APA, all rights reserved. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170005314','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170005314">Meteoroid Bulk Density and Ceplecha Types</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Blaauw, R. C.; Moser, D. E.; Moorhead, A. V. 2017-01-01 Determination of asteroid bulk density is an important aspect of NEO characterization, yet difficult to measure. As a fraction of meteoroids originate from asteroids (including some NEOs), a study of meteoroid bulk densities can potentially provide useful insights into the densities of NEOs and PHOs in lieu of mutual perturbations, satellite, or expensive spacecraft missions. NASA's Meteoroid Environment Office characterizes the meteoroid environment for the purpose of spacecraft risk and operations. To accurately determine the risk, a distribution of meteoroid bulk densities are needed. This is not trivial to determine. If the particle survives to the ground the bulk density can be directly measured, however only the most dense particles land on the Earth. The next best approach is to model the meteor's ablation, which is not straightforward. Clear deceleration is necessary to do this and there are discrepancies in results between models. One approach to a distribution of bulk density is to use a measured proxy for the densities, then calibrate the proxy with known densities from meteorite falls, ablation modelling, and other sources. An obvious proxy choice is the Ceplecha type, K(sub B), thought to indicate the strength of a meteoroid. KB is frequented cited as a good proxy for meteoroid densities, but we find it is poorly correlated with density. However, a distinct split by dynamical type was seen with Jovian Tisserand parameter, T(sub J), with meteoroids from Halley Type comets (T(sub J less than 2 ) exhibiting much lower densities than those originating from Jupiter and asteroids (T(sub J greater than 2). </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2270893','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2270893">Personality as a Prognostic Factor for Specialty Choice: A Prospective Study of 4 Medical School Classes</a> <a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Markert, Ronald J.; Rodenhauser, Paul; El-Baghdadi, Mariam M.; Juskaite, Kornelija; Hillel, Alexander T.; Maron, Bradley A. 2008-01-01 Background To augment the availability of medical care for a population that is older and more ethnically diverse, the number of US medical schools is increasing and existing medical schools are enlarging their class sizes. Predictors of specialty choice, especially primary care careers, are helpful to medical school officials and faculty involved in medical school recruitment and counseling and to students planning their career paths. Objective The objective was to examine the association between personality characteristics and specialty choice. Methods The Neuroticism-Extraversion-Openness Personality Inventory Revised (NEO PI-R) was administered to 4 Tulane University School of Medicine (New Orleans, Louisiana) classes (2003–2006). The NEO PI-R is a measure of 5 personality characteristics (neuroticism, extraversion, openness, agreeableness, and conscientiousness), with each domain having 6 underlying facets. The specialty choice of graduates was obtained from the National Residency Matching Program. Results Starting in 1999, 595 students matriculated and by June 2006, 542 (91%) had matched to residency programs in 22 specialties. There were differences among specialties for neuroticism (P = .006), openness (P < .001), and agreeableness (P = .003), but not for extraversion (P = .173) or conscientiousness (P = .103). Various pairwise differences between specialty categories were found. Discussion Eleven specialty categories were compared using the NEO PI-R. Numerous specialty variations were identified for neuroticism, openness, and agreeableness. The findings may be useful to medical school officials and faculty who recruit and counsel students and to students themselves as they reflect on their personality characteristics on their path to making career choices. PMID:18382718 </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010038566&hterms=Agreement&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DAgreement','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010038566&hterms=Agreement&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DAgreement">International Agreement on Planetary Protection</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> 2000-01-01 The maintenance of a NASA policy, is consistent with international agreements. The planetary protection policy management in OSS, with Field Center support. The advice from internal and external advisory groups (NRC, NAC/Planetary Protection Task Force). The technology research and standards development in bioload characterization. The technology research and development in bioload reduction/sterilization. This presentation focuses on: forward contamination - research on the potential for Earth life to exist on other bodies, improved strategies for planetary navigation and collision avoidance, and improved procedures for sterile spacecraft assembly, cleaning and/or sterilization; and backward contamination - development of sample transfer and container sealing technologies for Earth return, improvement in sample return landing target assessment and navigation strategy, planning for sample hazard determination requirements and procedures, safety certification, (liaison to NEO Program Office for compositional data on small bodies), facility planning for sample recovery system, quarantine, and long-term curation of 4 returned samples. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1992GeCoA..56.2993G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1992GeCoA..56.2993G">Some ideas on the rock cycle: 1788-1988</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Gregor, Bryan 1992-08-01 Hutton's procrastination on the subject of unconformities left his cyclic vision of geology in the shadows, while his success in demonstrating the igneous origin of granite led on to Classical Magmatism, a paradigm of secular evolution that reigned practically unchallenged for almost a century. When radiometric dating revealed the true extent of geologic time, a neo-Huttonian, cyclic view gained strength in Europe because of its ability to explain the salt content of the ocean and the sodium fixed in metamorphism of sediments to paragneiss, both of which had become embarrassing to the magmatists. Meantime, in North America, a quite independent movement was afoot to claim for sediments and cyclic processes their rightful place in geologic theory. It led to the acknowledgment that the cyclic and secular views of the Earth are complementary and not contradictory, and that geologic materials are recycled on varying time scales against a background of slow, secular evolution of the Earth. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=Standardization+AND+processes&pg=4&id=EJ813114','ERIC'); return false;" href="https://eric.ed.gov/?q=Standardization+AND+processes&pg=4&id=EJ813114">The Erosion of the University as a Public Sphere</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Sit, Victoria 2008-01-01 Neo-liberal policies and programs regarding higher education operate to fulfill either one of two main goals. The first is the privatization of public education. The second objective is the creation of an "iron cage" of economic rationality and standardization, which functions to regulate the production of human capital in the public education… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED199089.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED199089.pdf">A Neo-Piagetian Approach to Development During the Formal Operational Period.</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Biemiller, Andrew Cognitive development during each of the major stages identified by Piaget is characterized by abilities to solve progressively more complex tasks (e.g., changes in the object concept during the sensori-motor stage, and in conservation of amount, weight, and volume during the concrete operational stage). Several theorists have suggested that these… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17942009','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17942009">Personality characteristics and affective status related to cognitive test performance and gender in patients with memory complaints.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Vestberg, Susanna; Passant, Ulla; Risberg, Jarl; Elfgren, Christina 2007-11-01 The aims are to study personality characteristics of patients with memory complaints and to assess the presence of objective (OMI) versus subjective (SMI) memory impairment, the affective status, as well as potential gender differences. The patients were assessed by means of a neuropsychiatric examination and a neuropsychological test-battery. The Swedish version of the revised NEO Personality Inventory (NEO PI-R) and the Hospital Anxiety and Depression Scale (HADS) were used. The 57 patients (38 women, 19 men, mean age 56.9) differed from the Swedish normative group in three of the five personality factors: neuroticism, extraversion and agreeableness. This was mainly because of the scores of the female patients. Approximately half of the patients had OMI. No differences regarding personality factors or affective status were found between OMI and SMI patients. The female patients scored significantly higher than the male patients on symptoms of anxiety and depression. Neuroticism and symptoms of depression interacted with memory performance and gender. Our findings demonstrate the importance of applying an objective assessment of memory functions and a gender perspective when studying patients with memory complaints. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DPS....4741501B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DPS....4741501B">Sizing Up the Comets: The NEOWISE Mission Survey of Cometary Nucleii</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Bauer, James M.; Grav, Tommy; Mainzer, A. K.; Kramer, Emily; Stevenson, Rachel A.; Fernández, Yanga R.; Masiero, Joseph R.; Nugent, Carolyn R.; Cutri, Roc M.; Sonnett, Sarah; Masci, Frank J.; Meech, Karen J.; Walker, Russel; Lisse, Carey M.; Weissman, Paul R.; Dailey, John W.; Blair, Nathan; Lucas, Andrew; McMillan, Robert S.; Wright, Edward L. 2015-11-01 The NEOWISE mission has provided the largest cometary survey in the infrared. The NEOWISE mission was originally an augmentation to detect solar system objects, and specifically Near Earth Objects, using the Wide-Field Infrared Survey Explorer (WISE) spacecraft. Funded by NASA's Planetary Division through the Near-Earth Object Observation program, NEOWISE detected moving objects throughout the WISE mission[1-2], after which the spacecraft was placed in a state of hybernation. After 32 months, the re-christened NEOWISE spacecraft was returned to a zenith-pointing orbit. On December 23, 2013, the reactivated survey began[3].While NEOWISE's primary purpose was the detection of NEOs, a total of 163 comets have been identified in the prime survey (January 7, 2010 - Febraury 1, 2011), and over 75 have been observed during the NEOWISE reactivate mission to date. These observations have been made at multiple epochs, often when the comets were at large heliocentric distances or exhibited little or no activity. Preliminary analysis of the 25 NEOWISE-discovered comets has indicated possible differences between the size distributions of long-period comets (LPCs) and short-period comets (SPCs) in their raw (not de-biased) samples[4]. On average the observed LPCs were larger than the SPCs. We will discuss the results of the analysis of the larger sample of more than 65 nucleii extracted from the prime mission data, as well as the reactivated mission sample.This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration, as well as data products from NEOWISE, which is a project of JPL/Caltech, funded by the Planetary Science Division of NASA. RS, SS, and EK were supported by the NASA Postdoctoral Program.[1] Cutri et al. 2013 (http://wise2.ipac.caltech.edu/docs/release/allsky/expsup/index.html)[2] Mainzer et al. 2011. ApJ 731, 53.[3] Mainzer et al. 2014. ApJ 792, 30.[4] Bauer, J. M. et al. 2015.The NEOWISE-Discovered Comet Population and the CO+CO2 production rates. ApJ. Submitted. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/EJ991958.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/EJ991958.pdf">Post Neo-Liberalism and the Humanities: What the Repressive State Apparatus Means for Universities</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Hyslop-Margison, Emery J.; Leonard, Hugh A. 2012-01-01 In this article we explore how neo-liberal and post neo-liberal policies threaten the humanities in post-secondary education as a potential site of democratic dialogue and social transformation. We distinguish between neo-liberalism and post neo-liberalism on the basis of the latter's increased police suppression of democratic dissent. We are… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=Hawthorn&id=EJ782926','ERIC'); return false;" href="https://eric.ed.gov/?q=Hawthorn&id=EJ782926">Personality and Approaches to Learning Predict Preference for Different Teaching Methods</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Chamorro-Premuzic, Tomas; Furnham, Adrian; Lewis, Martin 2007-01-01 A total of 221 (111 female and 110 male) British Medical students completed the NEO-FFI personality inventory [Costa, P. T., Jr., and McCrae, R. R. (1992). "Revised NEO Personality Inventory (NEO-PI-R) and NEO Five-Factor Inventory (NEO-FFI) professional manual." Odessa, FL: Psychological Assessment Resources.], an abbreviated version of Biggs'… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24162101','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24162101">The big five personality traits: psychological entities or statistical constructs?</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Franić, Sanja; Borsboom, Denny; Dolan, Conor V; Boomsma, Dorret I 2014-11-01 The present study employed multivariate genetic item-level analyses to examine the ontology and the genetic and environmental etiology of the Big Five personality dimensions, as measured by the NEO Five Factor Inventory (NEO-FFI) [Costa and McCrae, Revised NEO personality inventory (NEO PI-R) and NEO five-factor inventory (NEO-FFI) professional manual, 1992; Hoekstra et al., NEO personality questionnaires NEO-PI-R, NEO-FFI: manual, 1996]. Common and independent pathway model comparison was used to test whether the five personality dimensions fully mediate the genetic and environmental effects on the items, as would be expected under the realist interpretation of the Big Five. In addition, the dimensionalities of the latent genetic and environmental structures were examined. Item scores of a population-based sample of 7,900 adult twins (including 2,805 complete twin pairs; 1,528 MZ and 1,277 DZ) on the Dutch version of the NEO-FFI were analyzed. Although both the genetic and the environmental covariance components display a 5-factor structure, applications of common and independent pathway modeling showed that they do not comply with the collinearity constraints entailed in the common pathway model. Implications for the substantive interpretation of the Big Five are discussed. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014DPS....4641403C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014DPS....4641403C">Simulating the Performance of Ground-Based Optical Asteroid Surveys</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Christensen, Eric J.; Shelly, Frank C.; Gibbs, Alex R.; Grauer, Albert D.; Hill, Richard E.; Johnson, Jess A.; Kowalski, Richard A.; Larson, Stephen M. 2014-11-01 We are developing a set of asteroid survey simulation tools in order to estimate the capability of existing and planned ground-based optical surveys, and to test a variety of possible survey cadences and strategies. The survey simulator is composed of several layers, including a model population of solar system objects and an orbital integrator, a site-specific atmospheric model (including inputs for seeing, haze and seasonal cloud cover), a model telescope (with a complete optical path to estimate throughput), a model camera (including FOV, pixel scale, and focal plane fill factor) and model source extraction and moving object detection layers with tunable detection requirements. We have also developed a flexible survey cadence planning tool to automatically generate nightly survey plans. Inputs to the cadence planner include camera properties (FOV, readout time), telescope limits (horizon, declination, hour angle, lunar and zenithal avoidance), preferred and restricted survey regions in RA/Dec, ecliptic, and Galactic coordinate systems, and recent coverage by other asteroid surveys. Simulated surveys are created for a subset of current and previous NEO surveys (LINEAR, Pan-STARRS and the three Catalina Sky Survey telescopes), and compared against the actual performance of these surveys in order to validate the model’s performance. The simulator tracks objects within the FOV of any pointing that were not discovered (e.g. too few observations, too trailed, focal plane array gaps, too fast or slow), thus dividing the population into “discoverable” and “discovered” subsets, to inform possible survey design changes. Ongoing and future work includes generating a realistic “known” subset of the model NEO population, running multiple independent simulated surveys in coordinated and uncoordinated modes, and testing various cadences to find optimal strategies for detecting NEO sub-populations. These tools can also assist in quantifying the efficiency of novel yet unverified survey cadences (e.g. the baseline LSST cadence) that sparsely spread the observations required for detection over several days or weeks. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/14519348','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/14519348">Dynamic graciloplasty for urinary incontinence: the potential for sequential closed-loop stimulation.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Zonnevijlle, Erik D H; Perez-Abadia, Gustavo; Stremel, Richard W; Maldonado, Claudio J; Kon, Moshe; Barker, John H 2003-11-01 Muscle tissue transplantation applied to regain or dynamically assist contractile functions is known as 'dynamic myoplasty'. Success rates of clinical applications are unpredictable, because of lack of endurance, ischemic lesions, abundant scar formation and inadequate performance of tasks due to lack of refined control. Electrical stimulation is used to control dynamic myoplasties and should be improved to reduce some of these drawbacks. Sequential segmental neuromuscular stimulation improves the endurance and closed-loop control offers refinement in rate of contraction of the muscle, while function-controlling stimulator algorithms present the possibility of performing more complex tasks. An acute feasibility study was performed in anaesthetised dogs combining these techniques. Electrically stimulated gracilis-based neo-sphincters were compared to native sphincters with regard to their ability to maintain continence. Measurements were made during fast bladder pressure changes, static high bladder pressure and slow filling of the bladder, mimicking among others posture changes, lifting heavy objects and diuresis. In general, neo-sphincter and native sphincter performance showed no significant difference during these measurements. However, during high bladder pressures reaching 40 cm H(2)O the neo-sphincters maintained positive pressure gradients, whereas most native sphincters relaxed. During slow filling of the bladder the neo-sphincters maintained a controlled positive pressure gradient for a prolonged time without any form of training. Furthermore, the accuracy of these maintained pressure gradients proved to be within the limits set up by the native sphincters. Refinements using more complicated self-learning function-controlling algorithms proved to be effective also and are briefly discussed. In conclusion, a combination of sequential stimulation, closed-loop control and function-controlling algorithms proved feasible in this dynamic graciloplasty-model. Neo-sphincters were created, which would probably provide an acceptable performance, when the stimulation system could be implanted and further tested. Sizing this technique down to implantable proportions seems to be justified and will enable exploration of the possible benefits. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active">20</li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active">21</li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AstBu..70..342E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AstBu..70..342E">Dynamical features of hazardous near-Earth objects</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Emel'yanenko, V. V.; Naroenkov, S. A. 2015-07-01 We discuss the dynamical features of near-Earth objects moving in dangerous proximity to Earth. We report the computation results for the motions of all observed near-Earth objects over a 600-year-long time period: 300 years in the past and 300 years in the future. We analyze the dynamical features of Earth-approaching objects. In particular, we established that the observed distribution of geocentric velocities of dangerous objects depends on their size. No bodies with geocentric velocities smaller that 5 kms-1 have been found among hazardous objects with absolute magnitudes H <18, whereas 9% of observed objects with H <27 pass near Earth moving at such velocities. On the other hand, we found a tendency for geocentric velocities to increase at H >29. We estimated the distribution of absolute magnitudes of hazardous objects based on our analysis of the data for the asteroids that have passed close to Earth. We inferred the Earth-impact frequencies for objects of different sizes. Impacts of objects with H <18 with Earth occur on average once every 0.53 Myr, and impacts of objects with H <27—once every 130-240 years. We show that currently about 0.1% of all near-Earth objects with diameters greater than 10 m have been discovered. We point out the discrepancies between the estimates of impact rates of Chelyabinsk-type objects, determined from fireball observations and from the data of telescopic asteroid tracking surveys. These estimates can be reconciled assuming that Chelyabinsk-sized asteroids have very low albedos (about 0.02 on average). </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11433800','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11433800">Effects of positive impression management on the NEO Personality Inventory--Revised in a clinical population.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Ballenger, J F; Caldwell-Andrews, A; Baer, R A 2001-06-01 Sixty adults in outpatient psychotherapy completed the NEO Personality Inventory--Revised (NEO PI-R, P. T. Costa & R. R. McCrae, 1992a). Half were instructed to fake good and half were given standard instructions. All completed the Interpersonal Adjective Scale--Revised, Big Five (J. S. Wiggins & P. D. Trapnell, 1997) under standard instructions, and their therapists completed the observer rating form of the NEO Five-Factor Inventory. A comparison group of 30 students completed the NEO PI-R under standard instructions. Standard and fake-good participants obtained significantly different NEO PI-R domain scores. Correlations between the NEO PI-R and criterion measures were significantly lower for faking than for standard patients. Validity scales for the NEO PI-R (J. A. Schinka, B. N. Kinder, & T. Kremer, 1997) were moderately accurate in discriminating faking from standard patients, but were only marginally accurate in discriminating faking patients from students. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1693284','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1693284">Global analysis of river systems: from Earth system controls to Anthropocene syndromes.</a> <a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Meybeck, Michel 2003-01-01 Continental aquatic systems from rivers to the coastal zone are considered within two perspectives: (i) as a major link between the atmosphere, pedosphere, biosphere and oceans within the Earth system with its Holocene dynamics, and (ii) as water and aquatic biota resources progressively used and transformed by humans. Human pressures have now reached a state where the continental aquatic systems can no longer be considered as being controlled by only Earth system processes, thus defining a new era, the Anthropocene. Riverine changes, now observed at the global scale, are described through a first set of syndromes (flood regulation, fragmentation, sediment imbalance, neo-arheism, salinization, chemical contamination, acidification, eutrophication and microbial contamination) with their related causes and symptoms. These syndromes have direct influences on water uses, either positive or negative. They also modify some Earth system key functions such as sediment, water, nutrient and carbon balances, greenhouse gas emissions and aquatic biodiversity. Evolution of river syndromes over the past 2000 years is complex: it depends upon the stages of regional human development and on natural conditions, as illustrated here for the chemical contamination syndrome. River damming, eutrophication and generalized decrease of river flow due to irrigation are some of the other global features of river changes. Future management of river systems should also consider these long-term impacts on the Earth system. PMID:14728790 </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998uisr.workR...2B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998uisr.workR...2B">Near-Earth Asteroid Prospector and the Commercial Development of Space Resources</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Benson, Jim 1998-01-01 With the recent bad news that there may be little or no budget money for NASA to continue funding programs aimed at the human exploration of space beyond Earth's orbit, it becomes even more important for other initiatives to be considered. SpaceDev is the world' s first commercial space exploration company, and enjoys the strong support of Dan Goldin, Wes Huntress, Carl Pilcher, Alan Ladwig, and others at NASA headquarters. SpaceDev is also supported by such scientists as Jim Arnold, Paul Coleman, John Lewis, Steve Ostro, and many others. Taxpayers cannot be expected to carry the entire burden of exploration, construction, and settlement. The private sector must be involved, and the SpaceDev Near Earth Asteroid Prospector (NEAP) venture may provide a good example of how governments and the private sector can cooperate to accomplish these goals. SpaceDev believes that the utilization of in situ resources will take place on near-Earth asteroids before the Moon or Mars because many NEOs are energetically closer than the Moon or Mars and have a highly concentrated composition. SpaceDev currently expects to perform the following three missions: NEAP (science data gathering); NEAP 2, near-Earth asteroid or short-term comet sample return mission; and NEAP 3, in situ fuel production or resource extraction and utilization. These missions could pioneer the way for in situ resources for construction. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=js&id=EJ956929','ERIC'); return false;" href="https://eric.ed.gov/?q=js&id=EJ956929">Assessing the Five Factors of Personality in Adolescents: The Junior Version of the Spanish NEO-PI-R</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Ortet, Generos; Ibanez, Manuel I.; Moya, Jorge; Villa, Helena; Viruela, Ana; Mezquita, Laura 2012-01-01 This article presents the development of a junior version of the Spanish (Castilian) NEO Personality Inventory-Revised (JS NEO) suitable for adolescents aged 12 to 18 years. The psychometric properties of the new JS NEO were investigated using two samples of 2,733 and 983 adolescents in Spain. The results showed that the adult NEO-PI-R factor… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004cosp...35.2460M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004cosp...35.2460M">Collisional fragmentation of asteroids and its implication on the physical properties of Near-Earth Objects</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Michel, P. Collisions are at the origin of catastrophic disruptions in the asteroid Main Belt. This is witnessed by the observation of asteroid families, each composed of asteroids which originated from a single parent body, broken-up by a collision with another asteroid. Understanding the collisional process and its outcome properties is not only necessary in order to study the collisional evolution of small body population or the planetary formation, it is also strongly required in the context of mitigation strategies aimed at deviating a threatening asteroid. In the last three years, for the first time we have successfully performed numerical simulations of high speed collisions between small bodies which account for the production of gravitationally reaccumulated bodies. More precisely, we have developped a procedure which divides the process into two phases. Using a 3D SPH hydrocode, the fragmentation of the solid target through crack propagation is first computed. Then the simulation of the gravitational evolution and possible piecewise reaccumulation of the parent body is performed using the parallel N-body code pkdgrav. Our first simulations using monolithic parent bodies have succeeded in reproducing fundamental properties of some well-identified asteroid families, showing that gravitational re-accumulations following disruptive collisions are the key process accounting for the existence of asteroid families. Then, we have investigated the effect of the internal structure of the parent body on the outcome properties. We have thus shown that family parent bodies are likely to have already been pre-shattered by small impacts before being disrupted by a major event. We then suggested that the most likely internal structure of large asteroids in the main belt is not monolithic but rather composed of macroscopic fractures and voids. We will make a review of these simulations in three different impact regimes, from highly catastrophic to barely disruptive. In particular we will show the sensitivity of the resulting family characteristics upon the internal structure of the parent body. According to our current understanding, most NEOs are certainly fragments of larger asteroids of the Main Belt, injected either directly or by diffusion into main resonances that transported them to Earth-crossing orbits. According to our simulations, most NEOs with diameter larger than several hundreds of meters should then correspond to gravitational aggregates. Given the crucial role of the internal structure on the impact outcome, this has important implications in the development of efficient mitigation strategies. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1710153W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1710153W">Mantle convection on modern supercomputers</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Weismüller, Jens; Gmeiner, Björn; Mohr, Marcus; Waluga, Christian; Wohlmuth, Barbara; Rüde, Ulrich; Bunge, Hans-Peter 2015-04-01 Mantle convection is the cause for plate tectonics, the formation of mountains and oceans, and the main driving mechanism behind earthquakes. The convection process is modeled by a system of partial differential equations describing the conservation of mass, momentum and energy. Characteristic to mantle flow is the vast disparity of length scales from global to microscopic, turning mantle convection simulations into a challenging application for high-performance computing. As system size and technical complexity of the simulations continue to increase, design and implementation of simulation models for next generation large-scale architectures demand an interdisciplinary co-design. Here we report about recent advances of the TERRA-NEO project, which is part of the high visibility SPPEXA program, and a joint effort of four research groups in computer sciences, mathematics and geophysical application under the leadership of FAU Erlangen. TERRA-NEO develops algorithms for future HPC infrastructures, focusing on high computational efficiency and resilience in next generation mantle convection models. We present software that can resolve the Earth's mantle with up to 1012 grid points and scales efficiently to massively parallel hardware with more than 50,000 processors. We use our simulations to explore the dynamic regime of mantle convection assessing the impact of small scale processes on global mantle flow. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AdSpR..34.2344F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AdSpR..34.2344F">Planetary protection - some legal questions</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Fasan, E. 2004-01-01 When we legally investigate the topic of Planetary Protection, we have to realise that there are primarily two very distinct parts of our juridical work: We have to study lexlata, theexistingapplicableLaw, especially Space Law, and also lexferenda, whatshouldbethe law . With this in mind, we have to deliberate the legal meaning of the notions "Planetary", and "Protection". About " Planetary": Our own Earth is our most important planet. At present only here do exist human beings, who are sensu strictu the only legal subjects. We make the law, we have to apply it, and we are to be protected as well as bound by it. But what is further meant by "Planetary"? Is it planets in an astronomical sense only, the nine planets which revolve around our fixed star, namely the sun, or is it also satellites, moving around most of these planets, as our own Moon circles Earth. "The Moon and other Celestial Bodies (C.B.)" are subject to Space Law, especially to International Treaties, Agreements, Resolutions of the UN, etc. I propose that they and not only the planets in an strictly astronomical sense are to be protected. But I do not think that the said notion also comprises asteroids, comets, meteorites, etc. although they too belong to our solar system. Our investigation comes to the result that such bodies have a different (lesser) legal quality. Also we have to ask Protectionfrom what ? From: Natural bodies - Meteorites, NEO Asteroids, Comets which could hit Earth or C.B.Artificial Objects: Space Debris threatening especially Earth and near Earth orbits.Terrestrial Life - no infection of other celestial bodies. Alien life forms which could bring about "harmful contamination" of Earth and the life, above all human life, there, etc. Here, astrobiological questions have to be discussed. Special realms on C.B. which should be protected from electronic "noise" such as craters SAHA or Deadalus on the Moon, also taking into account the "Common Heritage" Principle. Then, we have to examine: Protectionwhere, of whom andofwhat: On Earth: Humans, and nature, namely other life forms, air, water and soil, but also all man made things. On Other celestial bodies: Crew of manned Space Missions, Stations on C.B., possible alien life forms, or remnants of such, water, other environment on C.B. - even if completely barren? Protection of C.B. from becoming "an area of international conflict". Finally, we have to discuss overriding interests, such as deflection of Asteroids which threaten to hit Earth, then the legally permitted "Use" of C.B., also mining versus protection, then, too high costs of absolutely sterile Spacecraft, etc. With this, we have de lege ferenda to create an order of values of protection, whereby the protection of the higher category has priority over the lesser ones. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27885570','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27885570">Neo-Darwinists and Neo-Aristotelians: how to talk about natural purpose.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Woodford, Peter 2016-12-01 This paper examines the points of disagreement between Neo-Darwinian and recent Neo-Aristotelian discussions of the status of purposive language in biology. I discuss recent Neo-Darwinian "evolutionary" treatments and distinguish three ways to deal with the philosophical status of teleological language of purpose: teleological error theory, methodological teleology, and Darwinian teleological realism. I then show how "non-evolutionary" Neo-Aristotelian approaches in the work of Michael Thompson and Philippa Foot differ from these by offering a view of purposiveness grounded in life-cycle patterns, rather than in long-term evolutionary processes or natural selection. Finally, I argue that the crucial difference between Neo-Darwinian and Neo-Aristotelian approaches regards the question of whether or not reproduction deserves the status of an "ultimate" aim of organisms. I offer reasons to reject the concept of an "ultimate" aim in evolutionary biology and to reject the notion that reproduction serves a purpose. I argue that evolutionary biology is not in the position to determine what the "ultimate" explanation of natural purpose is. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23398091','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23398091">Revised NEO Personality Inventory normative data for police officer selection.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Detrick, Paul; Chibnall, John T 2013-11-01 The Revised NEO Personality Inventory (NEO PI-R) has demonstrated utility in the personnel selection context. Its use in police officer selection has been relatively limited, in part, because there are no published normative data for the NEO PI-R for police officer applicants. The authors present normative data on NEO PI-R domain and facet scores for a large sample (N = 288) of police officer applicants in a large, urban, Midwestern police department who completed the NEO PI-R as part of a preemployment psychological evaluation. Applicants reported low levels of Neuroticism and high levels of Extraversion and Conscientiousness. Neuroticism and Conscientiousness scores were strongly and consistently correlated with the Positive Presentation Management (PPM) research validity scale of the NEO PI-R. Extraversion and Agreeableness scores were moderately and less consistently correlated with PPM. These data may serve as a normative comparison group for professionals and researchers who use or may want to use the NEO PI-R in the police officer selection context. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMED22A..07M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMED22A..07M">International Astronomical Search Collaboration: Online Educational Outreach Program in Astronomical Discovery for Middle School, High School, & College Students and Citizen Scientists</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Miller, P. 2016-12-01 The International Astronomical Search Collaboration (IASC = "Isaac") in an online educational outreach program in planetary science. Citizen scientists and students from middle schools, high schools, and colleges make original discoveries of Main Belt asteroids. They discover trans-Neptunian objects and near-Earth objects. To date there have been discoveries of 1300 provisional MBAs, 7 TNOs, 2 potentially hazardous NEOs, and one Jupiter-family comet 276P/Vorobjov. IASC receives images from the Institute for Astronomy, University of Hawaii. Images are provided by the 1.8-m Pan-STARRS telescopes (PS1, PS2). These telescopes have the world's largest CCD cameras that produce 3o fields containing 1.4 billion pixels. These images are partitioned into 208 sub-images that are distributed online to the participating citizen scientists and schools (see http://iasc.hsutx.edu). Using the software Astrometrica, the sub-images are searched for moving object discoveries that are recorded with astrometry then reported to the Minor Planet Center (Smithsonian Astrophysical Observatory, Harvard). There are >5,000 citizen scientists and 700 schools that participate in the IASC asteroid searches. They come from more than 80 countries. And, the cost to participate…is free. Of the 1300 provisional MBA discoveries, 39 have been numbered and cataloged by the International Astronomical Union (Paris). The numbered discoveries are named by their citizen scientist and student discoverers. IASC works in conjunction with the NASA Asteroid Grand Challenge providing digital badging to the students (https://www.nasa.gov/feature/the-asteroid-grand-challenge-digital-badging-effort). IASC works online with the teachers from the participating schools, training them using videoconferencing to use Astrometrica in the search for, measurement of, and reporting of MBA discoveries by their students. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007amos.confE..79M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007amos.confE..79M">Missing in Action? Evaluating the Putative Absence of Impacts by Large Asteroids and Comets during the Quaternary Period</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Masse, W.; Weaver, R.; Abbott, D.; Gusiakov, V.; Bryant, E. The Quaternary period represents the interval of oscillating climatic extremes (glacial and interglacial periods) beginning about 2.6 million years ago to the present. Based on modeling by the Near Earth Object (NEO) community of planetary scientists, the known and validated record of Quaternary impact on Earth by comets and asteroids is seemingly depauperate in terms of larger impactors of 10,000+ Mt (roughly equal to or larger than about 500 m in diameter). Modeling suggests that an average of between 2-3 and perhaps as many as 5 globally catastrophic (ca. 1,000,000+ Mt) impacts by asteroids and comets could have occurred on Earth during this period of time, each having catastrophic regional environmental effects and moderate to severe continental and global effects. A slightly larger number of substantive but somewhat less than globally catastrophic impacts in the 10,000-100,000 Mt range would also be predicted to have occurred during the Quaternary. However, databases of validated impact structures on Earth, contain only two examples of Quaternary period impacts in the 10,000-100,000 Mt range (Zhamanshin, Bosumtwi), dating to around a million years ago, while no examples of Quaternary period globally catastrophic impact structures have been yet identified. In addition, all of the 27 validated Quaternary period impact structures are terrestrial--no Quaternary period oceanic impacts have been yet validated. Two likely globally catastrophic probable oceanic impacts events, Eltanin (ca. 1,000,000 Mt at around 2.5 mya), and that associated with the Australasian tektite strewn field (> 1,000,000 Mt at around 0.8 mya), are known due to their debris fields for which craters have not yet been identified and validated. These and the 8-km diameter Bolivian Iturralde candidate impact structure (ca. 10,000 Mt at around 20 kya) round out our list of likely large Quaternary impact structures. This suggests that one or more Quaternary period globally catastrophic impacts and several events in the 10,000-100,000 Mt range occurred in oceanic settings and have not yet been identified. At issue here is the default position of the NEO community that no large impacts have occurred during the past 15,000 years and that there is little evidence for human death by impacts during the past 5000 years of recorded history. This bias, deriving largely from reliance on stochastic models and by selectively ignoring physical, anthropological, and archaeological evidence in support of such impacts, is apparent in the messages being given to the media and general public, and in the general lack of grant support and other assistance to scientists and scholars wishing to conduct fieldwork on impacts that may date to the past 15,000 years. Such a position has a chilling effect on what should otherwise be an important arena of inquiry into the risks and effects of cosmic impact on human society. It potentially limits advancement in our understanding of the recent record and flux of cosmic impact, and diverts attention away from significant research questions such as the possible role of impact in Quaternary period climate change and biological and cultural evolution and process. LA-UR-07-2526. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AIPC..886..123V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AIPC..886..123V">Critical Trajectories for the Human Settlement of the High Frontier</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Valentine, Lee S. 2007-02-01 If preservation and prosperity of humanity on the Earth and human settlement of space are our goals, we should concentrate on a commercial path to get there. Commercial enterprise has a long history of fortuitously aiding scientific progress. We expect radical changes in the cost of earth to orbit transportation, and in the methods and efficacy of deep space transportation, within the next two decades. A successful space tourism industry, beginning with suborbital tourism, will greatly drive down the cost of access to orbit over the next 15 years. Inexpensive transportation to low Earth orbit is the first requirement for a great future on the High Frontier. Inexpensive means the cost associated with a mature transportation system. A mature system has a cost of three to five times the cost of the propellant. The first cheap, reliable and highly reusable rocket engines are just now appearing in vehicles. With an assured market and high flight rate, the heretofore glacial progress in reducing the cost of space transportation is likely to become rapid. This is the first critical enabling example of synergy between free market economics and scientific and technical progress in space. It will not be the last. New high power switches and ultracapacitors developed for the automotive market make possible cheap, robust and reliable mass driver engines. In space construction, using masses of nonterrestrial materials make the gravity tractor technique much more capable than previous schemes to maneuver asteroids. Ion propulsion will continue to improve and the first solar sails will be flown. Advanced robotics will allow remarkable improvements in productivity. The computing power available to robots began to follow the exponential Moore's law less than decade ago. The first commercial autonomous mobile robots appeared in late summer 2006. Humans, however, will be required for the foreseeable future in repair and supervisory roles, particularly in unstructured settings such as asteroid mines. The evolution from small tourist stations of the next decade to large space hotels will make economical the use of fully closed life-support systems. These could be considered the first space colonies. Derivatives of these commercial space hotels may form suitable Moon and asteroid mining habitats. Using nonterrestrial materials is a key to opening the space frontier. Dozens of rendezvous missions to Near Earth Objects will be needed to assay their resources and to plan rational NEO diversion. The development of NEO mining techniques serves two purposes, raw materials supply and planetary defense. We need economical trajectories to and from these bodies. These trajectories must not only be economical in terms of delta V or time, but in dollars, and in the time value of money, factors not generally considered by the OMB. Satellite solar power stations may be a $500 billion per year market worldwide and cheap nickel steel from asteroids may be an enabler of power satellite construction. One asteroid of the right size and composition in a suitable orbit could open this market. Platinum group metals may be an important export, either as a primary product, or as a byproduct of nickel steel alloy production. Other products, derived from carbon, may also be important. The first economical product from an asteroid mine is likely to be water, for propellant or life-support and radiation shielding in space hotels. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2929931','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2929931">Assessing the Universal Structure of Personality in Early Adolescence: The NEO-PI-R and NEO-PI-3 in 24 Cultures</a> <a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> De Fruyt, Filip; De Bolle, Marleen; McCrae, Robert R.; Terracciano, Antonio; Costa, Paul T. 2010-01-01 The structure and psychometric characteristics of the NEO-PI-3, a more readable version of the NEO-PI-R, are examined and compared with NEO-PI-R characteristics using data from college student observer ratings of 5,109 adolescents aged 12 to 17 from 24 cultures. Replacement items in the PI-3 showed on average stronger item/total correlations and slightly improved facet reliabilities compared with the NEO-PI-R in both English- and non-English-speaking samples. NEO-PI-3 replacement items did not substantially affect scale means compared with the original scales. Analyses across and within cultures confirmed the intended factor structure of both versions when used to describe young adolescents. We discuss implications of these cross-cultural findings for the advancement of studies in adolescence and personality development across the lifespan. PMID:19419953 </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=ptsd+AND+combat&pg=4&id=EJ478960','ERIC'); return false;" href="https://eric.ed.gov/?q=ptsd+AND+combat&pg=4&id=EJ478960">NEO-P1 Profiles in PTSD as a Function of Trauma Level.</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Talbert, F. Suzanne; And Others 1993-01-01 Administered NEO Personality Inventory (NEO-PI) and Combat Exposure Scale to 100 Vietnam veterans with combat-related Posttraumatic Stress Disorder (PTSD) and sorted subjects into three groups based on trauma exposure level. Found no significant differences among personality profiles of three trauma-exposed groups. Revealed normative NEO-PI… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=Gan&pg=7&id=EJ638525','ERIC'); return false;" href="https://eric.ed.gov/?q=Gan&pg=7&id=EJ638525">Indigenous Chinese Personality Constructs: Is the Five-Factor Model Complete?</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Cheung, Fanny M.; Leung, Kwok; Zhang, Jian-Xin; Sun, Hai-Fa; Gan, Yi-Qun; Song, Wei-Zhen; Xie, Dong 2001-01-01 Three studies involving Chinese respondents from China and Hong Kong and diverse respondents from Hawaii compared the Chinese Personality Assessment Inventory factor structure with the Revised NEO Personality Inventory (NEO-PI-R) and NEO-Five Factor Inventory. Results supported the universality of the five-factor model, the validity of NEO-PI-R,… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=Capitalism+AND+Freedom&pg=5&id=EJ330798','ERIC'); return false;" href="https://eric.ed.gov/?q=Capitalism+AND+Freedom&pg=5&id=EJ330798">Neo-Conservatives as Social Darwinists: Implications for Higher Education.</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Sola, Peter; And Others 1986-01-01 Compares the Social Darwinism of the 1890s with neo-conservatism of the 1980s. Discusses the ideologies of fair play versus fair shares, the theory of supply-side economics, and the implications of neo-conservatism for higher education. Argues that neo-conservatism is altering radically our conceptions of democracy, equality, and freedom. (KH) </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17518549','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17518549">The utility of the NEO-PI-R validity scales to detect response distortion: a comparison with the MMPI-2.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Morasco, Benjamin J; Gfeller, Jeffrey D; Elder, Katherine A 2007-06-01 In this psychometric study, we compared the recently developed Validity Scales from the Revised NEO Personality Inventory (NEO PI-R; Costa & McCrae, 1992b) with the MMPI-2 (Butcher, Dahstrom, Graham, Tellegen, & Kaemmer, 1989) Validity Scales. We collected data from clients (n = 74) who completed comprehensive psychological evaluations at a university-based outpatient mental health clinic. Correlations between the Validity Scales of the NEO-PI-R and MMPI-2 were significant and in the expected directions. The relationships provide support for convergent and discriminant validity of the NEO-PI-R Validity Scales. The percent agreement of invalid responding on the two measures was high, although the diagnostic agreement was modest (kappa = .22-.33). Finally, clients who responded in an invalid manner on the NEO-PI-R Validity Scales produced significantly different clinical profiles on the NEO-PI-R and MMPI-2 than clients with valid protocols. These results provide additional support for the clinical utility of the NEO-PI-R Validity Scales as indicators of response bias. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3760870','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3760870">Low Openness on the Revised NEO Personality Inventory as a Risk Factor for Treatment-Resistant Depression</a> <a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Takahashi, Michio; Shirayama, Yukihiko; Muneoka, Katsumasa; Suzuki, Masatoshi; Sato, Koichi; Hashimoto, Kenji 2013-01-01 Background Recently, we reported that low reward dependence, and to a lesser extent, low cooperativeness in the Temperature and Character Inventory (TCI) may be risk factors for treatment-resistant depression. Here, we analyzed additional psychological traits in these patients. Methods We administered Costa and McCrae's five-factor model personality inventory, NEO Personality Inventory-Revised (NEO-PI-R), to antidepressant-treatment resistant depressed patients (n = 35), remitted depressed patients (n = 27), and healthy controls (n = 66). We also evaluated the relationships between scores on NEO and TCI, using the same cohort of patients with treatment-resistant depression, as our previous study. Results Patients with treatment-resistant depression showed high scores for neuroticism, low scores for extraversion, openness and conscientiousness, without changes in agreeableness, on the NEO. However, patients in remitted depression showed no significant scores on NEO. Patients with treatment-resistant depression and low openness on NEO showed positive relationships with reward dependence and cooperativeness on the TCI. Conclusions Many studies have reported that depressed patients show high neuroticism, low extraversion and low conscientiousness on the NEO. Our study highlights low openness on the NEO, as a risk mediator in treatment-resistant depression. This newly identified trait should be included as a risk factor in treatment-resistant depression. PMID:24019864 </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24019864','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24019864">Low openness on the revised NEO personality inventory as a risk factor for treatment-resistant depression.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Takahashi, Michio; Shirayama, Yukihiko; Muneoka, Katsumasa; Suzuki, Masatoshi; Sato, Koichi; Hashimoto, Kenji 2013-01-01 Recently, we reported that low reward dependence, and to a lesser extent, low cooperativeness in the Temperature and Character Inventory (TCI) may be risk factors for treatment-resistant depression. Here, we analyzed additional psychological traits in these patients. We administered Costa and McCrae's five-factor model personality inventory, NEO Personality Inventory-Revised (NEO-PI-R), to antidepressant-treatment resistant depressed patients (n=35), remitted depressed patients (n=27), and healthy controls (n=66). We also evaluated the relationships between scores on NEO and TCI, using the same cohort of patients with treatment-resistant depression, as our previous study. Patients with treatment-resistant depression showed high scores for neuroticism, low scores for extraversion, openness and conscientiousness, without changes in agreeableness, on the NEO. However, patients in remitted depression showed no significant scores on NEO. Patients with treatment-resistant depression and low openness on NEO showed positive relationships with reward dependence and cooperativeness on the TCI. Many studies have reported that depressed patients show high neuroticism, low extraversion and low conscientiousness on the NEO. Our study highlights low openness on the NEO, as a risk mediator in treatment-resistant depression. This newly identified trait should be included as a risk factor in treatment-resistant depression. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active">21</li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active">22</li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28349855','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28349855">Reliability of the NEO Five Factor Inventory short form for assessing personality after stroke.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Dwan, Toni; Ownsworth, Tamara; Donovan, Caroline; Lo, Ada Ho Yan 2017-07-01 It is well recognized that an individual's personality characteristics influence their psychological adjustment after stroke. However, there is a lack of research on the reliability of personality inventories for stroke. This study primarily aimed to evaluate the reliability of the Neuroticism, Extroversion, Openness to Experience (NEO)-Five Factor Inventory (NEO-FFI) for assessing pre-morbid personality and personality changes after stroke. Further aims were to investigate changes in personality during the hospital-to-home transition period and examine associations between personality and mood. Forty participants with stroke (52.5% male, M age=65.55 years) were recruited at time of hospital discharge and completed the NEO-FFI, Centre for Epidemiologic Studies - Depression and Geriatric Anxiety Inventory. Significant others completed an informant version of the NEO-FFI. Stroke participants were re-assessed on the NEO-FFI at 1-month and 4-months post-discharge. Forty matched controls also completed the NEO-FFI. Internal consistency was adequate for the NEO-FFI (α=0.57-0.86), although low for agreeableness. There was fair to excellent concordance between self-rated and informant versions of the NEO-FFI (ICC=0.58-0.78). Significant positive associations were found between neuroticism and mood (r=0.50-0.68), and significant negative associations were found between extraversion and mood (r=-0.33-0.36) and agreeableness and anxiety (r=-0.43). Self-ratings of stroke participants on the NEO-FFI at discharge did not significantly differ from matched controls. Extraversion levels significantly decreased, and agreeableness levels significantly increased between discharge and 1- and 4-months post-discharge. Overall, the results support the reliability of the NEO-FFI for assessing personality characteristics in the context of stroke. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3953013','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3953013">Sex Chromosome Turnover Contributes to Genomic Divergence between Incipient Stickleback Species</a> <a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Yoshida, Kohta; Makino, Takashi; Yamaguchi, Katsushi; Shigenobu, Shuji; Hasebe, Mitsuyasu; Kawata, Masakado; Kume, Manabu; Mori, Seiichi; Peichel, Catherine L.; Toyoda, Atsushi; Fujiyama, Asao; Kitano, Jun 2014-01-01 Sex chromosomes turn over rapidly in some taxonomic groups, where closely related species have different sex chromosomes. Although there are many examples of sex chromosome turnover, we know little about the functional roles of sex chromosome turnover in phenotypic diversification and genomic evolution. The sympatric pair of Japanese threespine stickleback (Gasterosteus aculeatus) provides an excellent system to address these questions: the Japan Sea species has a neo-sex chromosome system resulting from a fusion between an ancestral Y chromosome and an autosome, while the sympatric Pacific Ocean species has a simple XY sex chromosome system. Furthermore, previous quantitative trait locus (QTL) mapping demonstrated that the Japan Sea neo-X chromosome contributes to phenotypic divergence and reproductive isolation between these sympatric species. To investigate the genomic basis for the accumulation of genes important for speciation on the neo-X chromosome, we conducted whole genome sequencing of males and females of both the Japan Sea and the Pacific Ocean species. No substantial degeneration has yet occurred on the neo-Y chromosome, but the nucleotide sequence of the neo-X and the neo-Y has started to diverge, particularly at regions near the fusion. The neo-sex chromosomes also harbor an excess of genes with sex-biased expression. Furthermore, genes on the neo-X chromosome showed higher non-synonymous substitution rates than autosomal genes in the Japan Sea lineage. Genomic regions of higher sequence divergence between species, genes with divergent expression between species, and QTL for inter-species phenotypic differences were found not only at the regions near the fusion site, but also at other regions along the neo-X chromosome. Neo-sex chromosomes can therefore accumulate substitutions causing species differences even in the absence of substantial neo-Y degeneration. PMID:24625862 </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1912272Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1912272Y">Prospects for infrasound bolide detections from balloon-borne platforms</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Young, Eliot; Bowman, Daniel; Arrowsmith, Stephen; Boslough, Marc; Klein, Viliam; Ballard, Courtney; Lees, Jonathan 2017-04-01 We report on an experiment to assess whether balloon-borne instruments can improve sensitivities to bolides exploding in the Earth's atmosphere (essentially using the atmosphere as a witness plate to characterize the small end of the NEO (Near Earth Object) population). The CTBTO's infrasound network regularly detects infrasound disturbances caused by bolides, including the 15-FEB-2013 Chelybinsk impact. Balloon-borne infrasound sensors should have two important advantages over ground-based infrasound stations: there should be virtually no wind noise on a free-floating platform, and a sensor in the stratosphere should benefit from its location within the stratospheric duct. Balloon-borne sensors also have the disadvantage that the amplitude of infrasound waves will decrease as they ascend with altitude. To test the performance of balloon-borne sensors, we conducted an experiment on a NASA high altitude (35 km) balloon launched from Ft Sumner, NM on 28-SEP-2016. We were able to put two independent infrasound payloads on this flight. We arranged for three 3000-lb ANFO explosions to be detonated from Socorro, NM at 12:00, 14:00 and 16:29:59 MST. The first two explosions were detected from the NASA balloon, with the first explosion showing three separate waveforms arriving within a 25-s span. The peak-to-peak amplitude of the waveforms was about 0.06 Pa, and the cleanest microphone channel detected this waveform with an SNR greater than 20. A second balloon at 15 km altitude also detected the second explosion. We have signals from a dozen ground stations at various positions from Socorro to Ft Sumner. We will report on wave propagation models and how they compare with observations from the two balloons and the various ground-stations. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140002261','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140002261">Fast, Large-Area, Wide-Bandgap UV Photodetector for Cherenkov Light Detection</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Wrbanek, John D.; Wrbanek, Susan Y. 2013-01-01 Due to limited resources available for power and space for payloads, miniaturizing and integrating instrumentation is a high priority for addressing the challenges of manned and unmanned deep space missions to high Earth orbit (HEO), near Earth objects (NEOs), Lunar and Martian orbits and surfaces, and outer planetary systems, as well as improvements to high-altitude aircraft safety. New, robust, and compact detectors allow future instrumentation packages more options in satisfying specific mission goals. A solid-state ultraviolet (UV) detector was developed with a theoretical fast response time and large detection area intended for application to Cherenkov detectors. The detector is based on the wide-bandgap semiconductor zinc oxide (ZnO), which in a bridge circuit can detect small, fast pulses of UV light like those required for Cherenkov detectors. The goal is to replace the role of photomultiplier tubes in Cherenkov detectors with these solid-state devices, saving on size, weight, and required power. For improving detection geometry, a spherical detector to measure high atomic number and energy (HZE) ions from any direction has been patented as part of a larger space radiation detector system. The detector will require the development of solid-state UV photodetectors fast enough (2 ns response time or better) to detect the shockwave of Cherenkov light emitted as the ions pass through a quartz, sapphire, or acrylic ball. The detector must be small enough to fit in the detector system structure, but have an active area large enough to capture enough Cherenkov light from the sphere. The detector is fabricated on bulk single-crystal undoped ZnO. Inter - digitated finger electrodes and contact pads are patterned via photolithography, and formed by sputtered metal of silver, platinum, or other high-conductivity metal. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017amos.confE..82G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017amos.confE..82G">A Phased Array of Widely Separated Antennas for Space Communication and Planetary Radar</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Geldzahler, B.; Bershad, C.; Brown, R.; Cox, R.; Hoblitzell, R.; Kiriazes, J.; Ledford, B.; Miller, M.; Woods, G.; Cornish, T.; D'Addario, L.; Davarian, F.; Lee, D.; Morabito, D.; Tsao, P.; Soloff, J.; Church, K.; Deffenbaugh, P.; Abernethy, K.; Anderson, W.; Collier, J.; Wellen, G. NASA has successfully demonstrated coherent uplink arraying with real time compensation for atmospheric phase fluctuations at 7.145-7.190 GHz (X-band) and is pursuing a similar demonstration 30-31 GHz (Ka-band) using three 12m diameter COTS antennas separated by 60m at the Kennedy Space Center in Florida. In addition, we have done the same demonstration with up to three 34m antennas separated by 250m at the Goldstone Deep Space Communication Complex in California at X-band 7.1 GHz. We have begun to infuse the capability at Goldstone into the Deep Space Network to provide a quasi-operational system. Such a demonstration can enable NASA to design and establish a high power (10 PW) high resolution (<10 cm), 24/7 availability radar system for (a) tracking and characterizing observations of Near Earth Objects (NEOs), (b) tracking, characterizing and determining the statistics of small-scale (≤10cm) orbital debris, (c) incorporating the capability into its space communication and navigation tracking stations for emergency spacecraft commanding in the Ka band era which NASA is entering, and (d) fielding capabilities of interest to other US government agencies. We present herein the results of our phased array uplink combining at near 7.17 and 8.3 GHz using widely separated antennas demonstrations, our moderately successful attempts to rescue the STEREO-B spacecraft (distance 2 astronomical units (185,000,000 miles), the first two attempts at imaging and ranging of near Earth asteroids, and progress in developing telescopes that are fully capable at radio and optical frequencies. And progress toward the implementation of our vision for going forward in implementing a high performance, low lifecycle cost multi-element radar array. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25785556','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25785556">Assessing human variability in kinetics for exposures to multiple environmental chemicals: a physiologically based pharmacokinetic modeling case study with dichloromethane, benzene, toluene, ethylbenzene, and m-xylene.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Valcke, Mathieu; Haddad, Sami 2015-01-01 The objective of this study was to compare the magnitude of interindividual variability in internal dose for inhalation exposure to single versus multiple chemicals. Physiologically based pharmacokinetic models for adults (AD), neonates (NEO), toddlers (TODD), and pregnant women (PW) were used to simulate inhalation exposure to "low" (RfC-like) or "high" (AEGL-like) air concentrations of benzene (Bz) or dichloromethane (DCM), along with various levels of toluene alone or toluene with ethylbenzene and xylene. Monte Carlo simulations were performed and distributions of relevant internal dose metrics of either Bz or DCM were computed. Area under the blood concentration of parent compound versus time curve (AUC)-based variability in AD, TODD, and PW rose for Bz when concomitant "low" exposure to mixtures of increasing complexities occurred (coefficient of variation (CV) = 16-24%, vs. 12-15% for Bz alone), but remained unchanged considering DCM. Conversely, AUC-based CV in NEO fell (15 to 5% for Bz; 12 to 6% for DCM). Comparable trends were observed considering production of metabolites (AMET), except for NEO's CYP2E1-mediated metabolites of Bz, where an increased CV was observed (20 to 71%). For "high" exposure scenarios, Cmax-based variability of Bz and DCM remained unchanged in AD and PW, but decreased in NEO (CV= 11-16% to 2-6%) and TODD (CV= 12-13% to 7-9%). Conversely, AMET-based variability for both substrates rose in every subpopulation. This study analyzed for the first time the impact of multiple exposures on interindividual variability in toxicokinetics. Evidence indicates that this impact depends upon chemical concentrations and biochemical properties, as well as the subpopulation and internal dose metrics considered. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5525445','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5525445">Fracture strength of orthodontic mini-implants</a> <a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Assad-Loss, Tatiana Feres; Kitahara-Céia, Flávia Mitiko Fernandes; Silveira, Giordani Santos; Elias, Carlos Nelson; Mucha, José Nelson 2017-01-01 ABSTRACT Objective: This study aimed at evaluating the design and dimensions of five different brands of orthodontic mini-implants, as well as their influence on torsional fracture strength. Methods: Fifty mini-implants were divided into five groups corresponding to different manufactures (DEN, RMO, CON, NEO, SIN). Twenty-five mini-implants were subjected to fracture test by torsion in the neck and the tip, through arbors attached to a Universal Mechanical Testing Machine. The other 25 mini-implants were subjected to insertion torque test into blocks of pork ribs using a torquimeter and contra-angle handpiece mounted in a surgical motor. The shape of the active tip of the mini-implants was evaluated under microscopy. The non-parametric Friedman test and Snedecor’s F in analysis of variance (ANOVA) were used to evaluate the differences between groups. Results: The fracture torque of the neck ranged from 23.45 N.cm (DEN) to 34.82 N.cm (SIN), and of the tip ranged from 9.35 N.cm (CON) to 24.36 N.cm (NEO). Insertion torque values ranged from 6.6 N.cm (RMO) to 10.2 N.cm (NEO). The characteristics that most influenced the results were outer diameter, inner diameter, the ratio between internal and external diameters, and the existence of milling in the apical region of the mini-implant. Conclusions: The fracture torques were different for both the neck and the tip of the five types evaluated. NEO and SIN mini-implants showed the highest resistance to fracture of the neck and tip. The fracture torques of both tip and neck were higher than the torque required to insert mini-implants. PMID:28746487 </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=social+AND+media+AND+public+AND+sphere&pg=4&id=EJ795548','ERIC'); return false;" href="https://eric.ed.gov/?q=social+AND+media+AND+public+AND+sphere&pg=4&id=EJ795548">Public Pedagogy and the Politics of Neo-Liberalism: Making the Political More Pedagogical</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Giroux, Henry A. 2004-01-01 Neo-liberalism has reached a new stage in the United States, buttressed largely by the almost seamless alliances formed among the Bush administration, religious fundamentalists, neo-conservative extremists, the dominant media, and corporate elites. This article explores the various ways in which neo-liberal cultural politics works as a form of… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020041471','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020041471">Long-Term Dynamics of Small Bodies in the Solar System</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Holman, Matthew J.; Grant, John (Technical Monitor) 2002-01-01 As part of the NASA Planetary Geology and Geophysics program, Prof. Norm Murray (CITA (Canadian Institute of Theoretical Astrophysics)) and I have been conducting investigations of the long-term dynamics of small bodies in the outer solar system. This grant, and its successor NAG5-10365, supports travel for collaboration by the Investigators and also supports Murray during an annual one month visit to the CfA (Harvard-Smithsonian Center for Astrophysics) for further collaboration. In the course of this grant we made a number of advances in solar system dynamics. For example, we developed an analytic model for the origin and consequence of chaos associated with three-body resonances in the asteroid belt. This has been shown to be important for the delivery of near Earth objects (NEO). We later extended this model to three-body resonances among planets. We were able to show that the numerically identified chaos among the outer planets results from a three-body resonance involving Jupiter, Saturn, and Uranus. The resulting paper was awarded the 1999 Newcomb Cleveland award from the AAAS (American Association for the Advancement of Science). This award singles out one paper published in Science each year for distinction. A list of grant-related publications is presented, with abstracts included. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AAS...21346004C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AAS...21346004C">LSST: Cadence Design and Simulation</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Cook, Kem H.; Pinto, P. A.; Delgado, F.; Miller, M.; Petry, C.; Saha, A.; Gee, P. A.; Tyson, J. A.; Ivezic, Z.; Jones, L.; LSST Collaboration 2009-01-01 The LSST Project has developed an operations simulator to investigate how best to observe the sky to achieve its multiple science goals. The simulator has a sophisticated model of the telescope and dome to properly constrain potential observing cadences. This model has also proven useful for investigating various engineering issues ranging from sizing of slew motors, to design of cryogen lines to the camera. The simulator is capable of balancing cadence goals from multiple science programs, and attempts to minimize time spent slewing as it carries out these goals. The operations simulator has been used to demonstrate a 'universal' cadence which delivers the science requirements for a deep cosmology survey, a Near Earth Object Survey and good sampling in the time domain. We will present the results of simulating 10 years of LSST operations using realistic seeing distributions, historical weather data, scheduled engineering downtime and current telescope and camera parameters. These simulations demonstrate the capability of the LSST to deliver a 25,000 square degree survey probing the time domain including 20,000 square degrees for a uniform deep, wide, fast survey, while effectively surveying for NEOs over the same area. We will also present our plans for future development of the simulator--better global minimization of slew time and eventual transition to a scheduler for the real LSST. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ProEn.204...69B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ProEn.204...69B">Smooth Particle Hydrodynamics GPU-Acceleration Tool for Asteroid Fragmentation Simulation</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Buruchenko, Sergey K.; Schäfer, Christoph M.; Maindl, Thomas I. 2017-10-01 The impact threat of near-Earth objects (NEOs) is a concern to the global community, as evidenced by the Chelyabinsk event (caused by a 17-m meteorite) in Russia on February 15, 2013 and a near miss by asteroid 2012 DA14 ( 30 m diameter), on the same day. The expected energy, from either a low-altitude air burst or direct impact, would have severe consequences, especially in populated regions. To mitigate this threat one of the methods is employment of large kinetic-energy impactors (KEIs). The simulation of asteroid target fragmentation is a challenging task which demands efficient and accurate numerical methods with large computational power. Modern graphics processing units (GPUs) lead to a major increase 10 times and more in the performance of the computation of astrophysical and high velocity impacts. The paper presents a new implementation of the numerical method smooth particle hydrodynamics (SPH) using NVIDIA-GPU and the first astrophysical and high velocity application of the new code. The code allows for a tremendous increase in speed of astrophysical simulations with SPH and self-gravity at low costs for new hardware. We have implemented the SPH equations to model gas, liquids and elastic, and plastic solid bodies and added a fragmentation model for brittle materials. Self-gravity may be optionally included in the simulations. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMIN13D..02M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMIN13D..02M">Design of Scalable and Effective Earth Science Collaboration Tool</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Maskey, M.; Ramachandran, R.; Kuo, K. S.; Lynnes, C.; Niamsuwan, N.; Chidambaram, C. 2014-12-01 Collaborative research is growing rapidly. Many tools including IDEs are now beginning to incorporate new collaborative features. Software engineering research has shown the effectiveness of collaborative programming and analysis. In particular, drastic reduction in software development time resulting in reduced cost has been highlighted. Recently, we have witnessed the rise of applications that allow users to share their content. Most of these applications scale such collaboration using cloud technologies. Earth science research needs to adopt collaboration technologies to reduce redundancy, cut cost, expand knowledgebase, and scale research experiments. To address these needs, we developed the Earth science collaboration workbench (CWB). CWB provides researchers with various collaboration features by augmenting their existing analysis tools to minimize learning curve. During the development of the CWB, we understood that Earth science collaboration tasks are varied and we concluded that it is not possible to design a tool that serves all collaboration purposes. We adopted a mix of synchronous and asynchronous sharing methods that can be used to perform collaboration across time and location dimensions. We have used cloud technology for scaling the collaboration. Cloud has been highly utilized and valuable tool for Earth science researchers. Among other usages, cloud is used for sharing research results, Earth science data, and virtual machine images; allowing CWB to create and maintain research environments and networks to enhance collaboration between researchers. Furthermore, collaborative versioning tool, Git, is integrated into CWB for versioning of science artifacts. In this paper, we present our experience in designing and implementing the CWB. We will also discuss the integration of collaborative code development use cases for data search and discovery using NASA DAAC and simulation of satellite observations using NASA Earth Observing System Simulation Suite (NEOS3). </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2096503','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2096503">One giant leap for mankind? A cost-utility analysis of abolishing the law of gravity</a> <a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Cyr, Claude; Lanthier, Luc 2007-01-01 Background Canada's Neo Rhino Party, a joke political party created in 2006 as a successor to the Parti Rhinocéros, is planning a new regulation to repeal the law of gravity, which could have an important impact on diseases attributable to gravity on earth. Methods We sought to estimate the number of quality-adjusted life-years that would be saved if the proposed regulation is passed and determine the cost-effectiveness of adapting Boris Volfson's antigravity machine1 for use on earth. We performed an economic analysis using a hidden Markov model. Results Our results suggest that a microgravity environment would save over 2 million quality-adjusted life-years. The cost for every quality-adjusted life-year saved is estimated to be $328. Interpretation Microgravity is the solution to the health care crisis in Canada. In addition, using technological, statistical and medical jargon gives us the opportunity to defy the laws of physics, mathematics and medicine. PMID:18056617 </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/56249','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/56249">Rapid neo-sex chromosome evolution and incipient speciation in a major forest pest</a> <a target="_blank" rel="noopener noreferrer" href="http://www.fs.usda.gov/treesearch/">Treesearch</a> Ryan R. Bracewell; Barbara J. Bentz; Brian T. Sullivan; Jeffrey M. Good 2017-01-01 Genome evolution is predicted to be rapid following the establishment of new (neo) sex chromosomes, but it is not known if neo-sex chromosome evolution plays an important role in speciation. Here we combine extensive crossing experiments with population and functional genomic data to examine neo-XY chromosome evolution and incipient speciation in the mountain pine... </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=801&pg=6&id=EJ735227','ERIC'); return false;" href="https://eric.ed.gov/?q=801&pg=6&id=EJ735227">Socially Desirable Responding and the Factorial Stability of the NEO PI-R</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Marshall, Margarita B.; De Fruyt, Filip; Rolland, Jean-Pierre; Bagby, R. Michael 2005-01-01 The goal of the present investigation is to compare the factor structure of the revised NEO Personality Inventory (NEO PI-R; P. T. Costa & R. R. McCrae, 1992) in samples of respondents differentially motivated to respond in a socially desirable manner. In the French sample, the authors compared the NEO PI-R structure of job applicants… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25756835','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25756835">Collaboration, not competition: cost analysis of neonatal nurse practitioner plus neonatologist versus neonatologist-only care models.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Bosque, Elena 2015-04-01 Although advanced practice in neonatal nursing is accepted and supported by the American Academy of Pediatrics and National Association of Neonatal Nurse Practitioners, less than one-half of all states allow independent prescriptive authority by advanced practice nurse practitioners. The purpose of this study was to compare costs of a collaborative practice model that includes neonatal nurse practitioner (NNP) plus neonatologist (Neo) versus a neonatologist only (Neo-Only) practice in Washington state. Published Internet median salary figures from 3 sources were averaged to produce mean ± SD provider salaries, and costs for each care model were calculated in this descriptive, comparative study. Median NNP versus Neo salaries were $99,773 ± $5206 versus $228,871 ± $9654, respectively (P < .0001). The NNP + Neo (5 NNP/3 Neo full-time equivalents [FTEs]) cost $1,185,475 versus Neo-Only (8 Neo FTEs) cost $1,830,960. The NNP + Neo practice model with 8 FTEs suggests a cost savings, with assumed equivalent reimbursement, of $645,485/year. These results may provide the impetus for more states to adopt broader scope of practice licensure for NNPs. These data may provide rationale for analysis of actual costs and outcomes of collaborative practice. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20379013','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20379013">Corrosion behavior of ion implanted nickel-titanium orthodontic wire in fluoride mouth rinse solutions.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Iijima, Masahiro; Yuasa, Toshihiro; Endo, Kazuhiko; Muguruma, Takeshi; Ohno, Hiroki; Mizoguchi, Itaru 2010-01-01 This study investigated the corrosion properties of ion implanted nickel-titanium wire (Neo Sentalloy Ionguard) in artificial saliva and fluoride mouth rinse solutions (Butler F Mouthrinse, Ora-Bliss). Non ion implanted nickel-titanium wire (Neo Sentalloy) was used as control. The anodic corrosion behavior was examined by potentiodynamic polarization measurement. The surfaces of the specimens were examined with SEM. The elemental depth profiles were characterized by XPS. Neo Sentalloy Ionguard in artificial saliva and Butler F Mouthrinse (500 ppm) had a lower current density than Neo Sentalloy. In addition, breakdown potential of Neo Sentalloy Ionguard in Ora-Bliss (900 ppm) was much higher than that of Neo Sentalloy although both wires had similar corrosion potential in Ora-Bliss (450 and 900 ppm). The XPS results for Neo Sentalloy Ionguard suggested that the layers consisted of TiO(2) and TiN were present on the surface and the layers may improve the corrosion properties. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19126440','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19126440">Neonatal status epilepticus alters prefrontal-striatal circuitry and enhances methamphetamine-induced behavioral sensitization in adolescence.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Lin, Tzu-Chao; Huang, Li-Tung; Huang, Ya-Ni; Chen, Gunng-Shinng; Wang, Jia-Yi 2009-02-01 Neonatal seizures may alter the developing neurocircuitry and cause behavioral abnormalities in adulthood. We found that rats previously subjected to lithium-pilocarpine (LiPC)-induced neonatal status epilepticus (NeoSE) exhibited enhanced behavioral sensitization to methamphetamine (MA) in adolescence. Neurochemically, dopamine (DA) and metabolites were markedly decreased in prefrontal cortex (PFC) and insignificantly changed in striatum by NeoSE, but were increased in both PFC and striatum by NeoSE+MA. Glutamate levels were increased in both PFC and striatum in the NeoSE+MA group. DA turnover, an index of utilization and activity, was increased by NeoSE but reversed by MA in PFC. Gene expression of the regulator of G-protein signaling 4 (RGS4) was downregulated in PFC and striatum by NeoSE and further suppressed by MA. These findings suggest NeoSE affects both dopaminergic and glutamatergic systems in the prefrontal-striatal circuitry that manifests as enhanced behavioral sensitization to MA in adolescence. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MsT.........11V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MsT.........11V">Characterizing Resident Space Object Earthshine Signature Variability</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Van Cor, Jared D. There are three major sources of illumination on objects in the near Earth space environment: Sunshine, Moonshine, and Earthshine. For objects in this environment (satellites, orbital debris, etc.) known as Resident Space Objects (RSOs), the sun and the moon have consistently small illuminating solid angles and can be treated as point sources; this makes their incident illumination easily modeled. The Earth on the other hand has a large illuminating solid angle, is heterogeneous, and is in a constant state of change. The objective of this thesis was to characterize the impact and variability of observed RSO Earthshine on apparent magnitude signatures in the visible optical spectral region. A key component of this research was creating Earth object models incorporating the reflectance properties of the Earth. Two Earth objects were created: a homogeneous diffuse Earth object and a time sensitive heterogeneous Earth object. The homogeneous diffuse Earth object has a reflectance equal to the average global albedo, a standard model used when modeling Earthshine. The time sensitive heterogeneous Earth object was created with two material maps representative of the dynamic reflectance of the surface of the earth, and a shell representative of the atmosphere. NASA's Moderate-resolution Imaging Spectroradiometer (MODIS) Earth observing satellite product libraries, MCD43C1 global surface BRDF map and MOD06 global fractional cloud map, were utilized to create the material maps, and a hybridized version of the Empirical Line Method (ELM) was used to create the atmosphere. This dynamic Earth object was validated by comparing simulated color imagery of the Earth to that taken by: NASAs Earth Polychromatic Imaging Camera (EPIC) located on the Deep Space Climate Observatory (DSCOVR), and by MODIS located on the Terra satellite. The time sensitive heterogeneous Earth object deviated from MODIS imagery by a spectral radiance root mean square error (RMSE) of +/-14.86 [watts/m. 2sr?m]over a sample of ROIs. Further analysis using EPIC imagery found a total albedo difference of +0.03% and a cross correlation of 0.656. Also compared to EPIC imagery it was found our heterogeneous Earth model produced a reflected Earthshine radiance RMSE of +/-28 [watts/m. 2sr?m] incident on diffuse sphericalRSOs, specular spherical RSOs, and diffuse flat plate RSOs with an altitude of 1000km; this resulted in an apparent magnitude error of +/-0.28. Furthermore, it was found our heterogeneous Earthmodel produced a reflected Earthshine radiance RMSE of +/-68 [watts/m. 2sr?m] for specular flat plate RSOs withan altitude of 1000km; this resulted in an apparent magnitude error of +/-0.68. The Earth objects were used in a workflow with the Digital Imaging and Remote Sensing Image Generation (DIRSIG) tool to explore the impact of a range of characteristic RSO geometries, geographies, orientations, and materials on the signatures from an RSO due to Earthshine. An apparent magnitude was calculated and used to quantify RSO Earthshine signature variability; this is discussed in terms of the RMSE and maximum deviations of visible RSO Earthshine apparent magnitude signatures comparing the homogeneous Earth model to heterogeneous Earth model. The homogeneous diffuse Earth object was shown to approximate visible RSO Earthshine apparent magnitude signatures from spheres with a RMSE in reflected Earthshine apparent magnitude of +/-0.4 and a maximum apparent magnitude difference of 1.09 when compared to the heterogeneous Earth model. Similarly for diffuse flat plates, the visible RSO Earthshine apparent magnitude signature RMSE was shown to be +/-0.64, with a maximum apparent magnitude difference of 0.82. For specular flat plates, the visible RSO Earthshine apparent magnitude signature RMSE was shown to be +/-0.97 with maximum apparent magnitude difference of 2.26. This thesis explored only a portion of the parameter dependencies of Earth shine, but has enabled a preliminary understanding of visible RSO Earthshine signature variability and its geometric dependence. This research has demonstrated the impact of Earth heterogeneity on the observed apparent magnitude signatures of RSOs illuminated by Earthshine and the potential for error that comes with approximating the Earth as a diffuse homogeneous object. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25531942','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25531942">High-throughput epitope discovery reveals frequent recognition of neo-antigens by CD4+ T cells in human melanoma.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Linnemann, Carsten; van Buuren, Marit M; Bies, Laura; Verdegaal, Els M E; Schotte, Remko; Calis, Jorg J A; Behjati, Sam; Velds, Arno; Hilkmann, Henk; Atmioui, Dris El; Visser, Marten; Stratton, Michael R; Haanen, John B A G; Spits, Hergen; van der Burg, Sjoerd H; Schumacher, Ton N M 2015-01-01 Tumor-specific neo-antigens that arise as a consequence of mutations are thought to be important for the therapeutic efficacy of cancer immunotherapies. Accumulating evidence suggests that neo-antigens may be commonly recognized by intratumoral CD8+ T cells, but it is unclear whether neo-antigen-specific CD4+ T cells also frequently reside within human tumors. In view of the accepted role of tumor-specific CD4+ T-cell responses in tumor control, we addressed whether neo-antigen-specific CD4+ T-cell reactivity is a common property in human melanoma. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active">22</li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active">23</li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA526641','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA526641">Optimizing Crisis Action Planning in the Noncombatant Evacuation Operation Setting</a> <a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a> 2010-06-01 Federal Regulations, the DoS has a firm rule to not enter into preemptive contracts for any logistical resources (e.g., transportation, food, water...bottlenecks, flow limiters, and options to quicken queues ; and identifying resources and transportation mediums that display the most sensitivity to...policy changes. These objectives were addressed by exploring topics in NEOs, evacuation planning, queueing systems, and modeling techniques and </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090026019','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090026019">Common Infrastructure for Neo Scientific and Planetary Defense Missions</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Adams, Robert; Wilks, Rodney 2009-01-01 While defending the Earth against collisions with asteroids and comets has garnered increasing attention over the past few decades, our knowledge of the threats and methods of mitigation remain inadequate. There exists a considerable gap in knowledge regarding the size, composition, location, internal structure and formation of near earth asteroids and comets. Although estimates have been made, critical experiments have not yet been conducted on the effectiveness of various proposed mitigation techniques. Closing this knowledge gap is of interest to both the planetary defense and planetary science communities. Increased scientific knowledge of asteroid and comet composition and structure can confirm or advance current theories about the formation of the solar system. This proposal suggests a joint effort between these two communities to provide an economical architecture that supports multiple launches of characterization and mitigation payloads with minimal response time. The science community can use this architecture for characterization missions of opportunity when multiple scientific targets or targets of uncommon scientific value present themselves, while the planetary defense community would be able to fire characterization or mitigation payloads at targets that present a threat to the Earth. Both communities would benefit from testing potential mitigation techniques, which would reveal information on the internal structure of asteroids and comets. In return, the Earth would have the beginnings of a viable response system should an impact threat prove real in the near future. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20030093626','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20030093626">Probable Disastrous Consequences of Collision Between Unknown Small (100 m) Asteroids with Known (Approximately 1 km) Near Earth Orbiting (NEO) Asteroids</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Smalley, Larry 2003-01-01 The long-term stability of the Solar System is not well understood. Ironically its stability is taken for granted even though our knowledge of all the constituents [comets, asteroids. (The Asteroid Belt between Mars and Jupiter, Trojan Asteroids, Kuiper belt, Ort Cloud), planetoids, planets, moons, etc], and its long-term dynamics cannot be easily computed. At best one might say that the solar system is chaotic, but much of the time it seems to exists near a quasi-stationary state. An asteroid that passes near the Earth regularly returns with clock-like precision. Taking into account every known detail of its path through the solar system, its orbit is calculated forward thousands of years with no untoward calamity on the horizon. And then one day, this passive visitor slams into the Earth during a sunny afternoon picnic! Can this happen? Unfortunately, this is a real possibility in the ordinary history of the solar system. In fact our knowledge of the solar system in the small is sketchy, as will be pointed out. Events, which lie outside our awareness, can precipitate disasters that we may perceive when it's too late to launch effective counter measures. In this work, one such scenario is described and the direct consequences for the Earth are calculated. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=narcissism&pg=4&id=EJ935121','ERIC'); return false;" href="https://eric.ed.gov/?q=narcissism&pg=4&id=EJ935121">A Comparison of Agreeableness Scores from the Big Five Inventory and the Neo PI-R: Consequences for the Study of Narcissism and Psychopathy</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Miller, Joshua D.; Gaughan, Eric T.; Maples, Jessica; Price, Joanna 2011-01-01 Despite being significantly correlated, there is evidence to suggest that the scales measuring Agreeableness from the Big Five Inventory (BFI) and the Revised NEO Personality Inventory (NEO PI-R) do not capture identical constructs. More specifically, NEO PI-R Agreeableness contains content related to "honesty and humility" that is not… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5354769','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5354769">The Netrin-4/ Neogenin-1 axis promotes neuroblastoma cell survival and migration</a> <a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Villanueva, Andrea A.; Falcón, Paulina; Espinoza, Natalie; Luis, Solano R.; Milla, Luis A.; Hernandez-SanMiguel, Esther; Torres, Vicente A.; Sanchez-Gomez, Pilar; Palma, Verónica 2017-01-01 Neogenin-1 (NEO1) is a transmembrane receptor involved in axonal guidance, angiogenesis, neuronal cell migration and cell death, during both embryonic development and adult homeostasis. It has been described as a dependence receptor, because it promotes cell death in the absence of its ligands (Netrin and Repulsive Guidance Molecule (RGM) families) and cell survival when they are present. Although NEO1 and its ligands are involved in tumor progression, their precise role in tumor cell survival and migration remain unclear. Public databases contain extensive information regarding the expression of NEO1 and its ligands Netrin-1 (NTN1) and Netrin-4 (NTN4) in primary neuroblastoma (NB) tumors. Analysis of this data revealed that patients with high expression levels of both NEO1 and NTN4 have a poor survival rate. Accordingly, our analyses in NB cell lines with different genetic backgrounds revealed that knocking-down NEO1 reduces cell migration, whereas silencing of endogenous NTN4 induced cell death. Conversely, overexpression of NEO1 resulted in higher cell migration in the presence of NTN4, and increased apoptosis in the absence of ligand. Increased apoptosis was prevented when utilizing physiological concentrations of exogenous Netrin-4. Likewise, cell death induced after NTN4 knock-down was rescued when NEO1 was transiently silenced, thus revealing an important role for NEO1 in NB cell survival. In vivo analysis, using the chicken embryo chorioallantoic membrane (CAM) model, showed that NEO1 and endogenous NTN4 are involved in tumor extravasation and metastasis. Our data collectively demonstrate that endogenous NTN4/NEO1 maintain NB growth via both pro-survival and pro-migratory molecular signaling. PMID:28038459 </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26494844','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26494844">Ancient Male Recombination Shaped Genetic Diversity of Neo-Y Chromosome in Drosophila albomicans.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Satomura, Kazuhiro; Tamura, Koichiro 2016-02-01 Researchers studying Y chromosome evolution have drawn attention to neo-Y chromosomes in Drosophila species due to their resembling the initial stage of Y chromosome evolution. In the studies of neo-Y chromosome of Drosophila miranda, the extremely low genetic diversity observed suggested various modes of natural selection acting on the nonrecombining genome. However, alternative possibility may come from its peculiar origin from a single chromosomal fusion event with male achiasmy, which potentially caused and maintained the low genetic diversity of the neo-Y chromosome. Here, we report a real case where a neo-Y chromosome is in transition from an autosome to a typical Y chromosome. The neo-Y chromosome of Drosophila albomicans harbored a rich genetic diversity comparable to its gametologous neo-X chromosome and an autosome in the same genome. Analyzing sequence variations in 53 genes and measuring recombination rates between pairs of loci by cross experiments, we elucidated the evolutionary scenario of the neo-Y chromosome of D. albomicans having high genetic diversity without assuming selective force, i.e., it originated from a single chromosomal fusion event, experienced meiotic recombination during the initial stage of evolution and diverged from neo-X chromosome by the suppression of recombination tens or a few hundreds of thousand years ago. Consequently, the observed high genetic diversity on the neo-Y chromosome suggested a strong effect of meiotic recombination to introduce genetic variations into the newly arisen sex chromosome. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1573279','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1573279">Neostigmine interactions with non steroidal anti-inflammatory drugs</a> <a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Miranda, Hugo F; Sierralta, Fernando; Pinardi, Gianni 2002-01-01 The common mechanism of action of non-steroidal anti-inflammatory drugs (NSAIDs) is the inhibition of the enzyme cyclo-oxygenase (COX), however, this inhibition is not enough to completely account for the efficacy of these agents in several models of acute pain. It has been demonstrated that cholinergic agents can induce antinociception, but the nature of the interaction between these agents and NSAIDs drugs has not been studied. The present work evaluates, by isobolographic analysis, the interactions between the cholinergic indirect agonist neostigmine (NEO) and NSAIDs drugs, using a chemical algesiometric test. Intraperitoneal (i.p.) or intrathecal (i.t.) administration of NEO and of the different NSAIDs produced dose-dependent antinociception in the acetic acid writhing test of the mouse. The i.p. or i.t. co-administration of fixed ratios of ED50 fractions of NSAIDs and NEO, resulted to be synergistic or supra-additive for the combinations ketoprofen (KETO) and NEO, paracetamol (PARA) and NEO) and diclofenac (DICLO) and NEO administered i.p. However, the same combinations administered i.t. were only additive. In addition, the combinations meloxicam (MELO) and NEO and piroxicam (PIRO) and NEO, administered either i.p. or i.t., were additive. The results suggest that the co-administration of NEO with some NSAIDs (e.g. KETO, PARA or DICLO) resulted in a synergistic interaction, which may provide evidence of supraspinal antinociception modulation by the increased acetylcholine concentration in the synaptic cleft of cholinergic interneurons. The interaction obtained between neostigmine and the NSAIDs could carry important clinical implications. PMID:11934798 </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19783563','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19783563">Migration and hypertension: a cross-sectional study among neo-migrants and settled-migrants in Delhi, India.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Kusuma, Yadlapalli; Gupta, Sanjeev; Pandav, Chandrakant 2009-10-01 Understanding the blood pressure (BP) distribution within populations is fundamental to an understanding of the etiology of cardiovascular diseases and to develop effective preventive strategies. This study focuses on whether the BP levels and hypertension prevalence differ between neo-migrants and settled-migrants in the city of Delhi. Data on BP, anthropometry, social variables, and demographic variables were collected from a cross-sectional sample of 226 settled-migrants and 227 neo-migrants. Men possessed significantly higher BP levels than women. Settled-migrants possessed higher BP levels, except diastolic BP in males. The prevalence of hypertension ranges from 15% (neo-migrant women) to 25% (settled-migrant men), with no significant gender differences. Group differences were significant for men. Hypertension was more prevalent in older settled-migrants and younger neo-migrants. Recent migration was found to be a significant contributor to hypertension prevalence. Age contributed significantly to BP variation in both groups except in neo-migrant men. Pulse rate also contributed to systolic BP among neo-migrant women and settled-migrant men. Thus, urban residence and migration to urban areas can be a leading cause of increased prevalence of hypertension. Neo-migrants were subjected to more lifestyle insults and the stress generated during the adjustment process may be contributing to rise of BP even at younger ages. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002bss..confE...5T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002bss..confE...5T">Coordination of NEO Observers in South-America</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Tancredi, G. At present the discovery of NEOs is concentrated in the Northern Hemisphere. None of the 6 existing survey programs can reach declinations below -30deg. Nevertheless, there are two small surveys ready to start in the near future in the southern hemisphere: an extension of the Catalina Sky Survey using the Uppsala Schmidt in Siding Spring and the Project BUSCA in Uruguay. Many of the NEOs discovered by the northern surveys could reach the southern sky, with declinations unreachable for a northern observer. Furthermore, the recovery of an asteroid in subsequent oppositions could come indistinctly in the northern and southern sky. A network of well-equipped observers in the southern region is then a must in a campaign to catalog the NEO population. In view of this situation, the Planetary Society, through its NEO grant, have already supported many observers in the Southern Hemisphere. The planetary science community in South America has considerably grown in the last 10 years. We have well-known research groups in Argentina, Brazil and Uruguay. Those groups have established many scientific links by exchanging graduate students and through several meetings. In particular, we have already hold two Workshop in Planetary Science in South America in 1999 (La Plata, Argentina) and 2000 (Montevideo, Uruguay) with more than 25 participants each. Recently, in February 2002, we organized a Workshop of NEO observers in Montevideo with the participation of more than 20 professional and amateurs observers from: Argentina: Obs. Ast. Felix Aguilar - Yale University (San Juan) and CRICYT (Mendoza); Brazil: Obs. Abraes de Moraes (San Pablo), Obs. Wykrota (Belo Horizonte) and Observatorio Nacional (Rio de Janeiro); Paraguay: Obs. Nacional de Asuncion and Sociedad de Estudios Astronómicos (Asunción) Uruguay: Depto. Astronomía - Fac. Ciencias, Obs. Ast. Los Molinos and Obs. Kappa Crucis (Montevideo). Among the resolutions of the Workshop, we highlight: * Creation of the "Asociación Spaceguard SudAmérica - SouthAmerican Spaceguard Association" to give a frame for the coordination of our activities * Established a web service to exchange information about our observing plans, objects in need of follow-up only reachable by southern observers, software exchange, etc. * Support the efforts of the astronomers of the Cordoba and La Plata Observatory to catalog the archive plates, useful for pre-discovery images. The members of our group own or have access to more than a dozen telescopes up to 60cm in size. We have already created a discussion list (spaceguard-sa@fisica.edu.uy) to start our coordination efforts. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4820901B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4820901B">Fast Prediction of Blast Damage from Airbursts: An Empirical Monte Carlo approach</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Brown, Peter G.; Stokan, Ed 2016-10-01 The February 15, 2013 Chelyabinsk airburst was the first modern bolide whose associated shockwave caused blast damage at the ground (Popova et al., 2013). Near-Earth Object (NEO) impacts in the Chelyabinsk-size range (~20 m) are expected to occur every few decades (Boslough et al., 2015) and therefore we expect ground damage from meteoric airbursts to be the next planetary defense threat to be confronted. With pre-impact detections of small NEOs certain to become more common, decision makers will be faced with estimating blast damage from impactors with uncertain physical properties on short timescales.High fidelity numerical bolide entry models have been developed in recent years (eg. Boslough and Crawford, 2008; Shuvalov et al., 2013), but the wide range in a priori data about strength, fragmentation behavior, and other physical properties for a specific impactor make predictions of bolide behavior difficult. The long computational running times for hydrocode models make the exploration of a wide parameter space challenging in the days to hours before an actual impact.Our approach to this problem is to use an analytical bolide entry model, the triggered-progressive fragmentation model (TPFM) developed by ReVelle (2005) within a Monte Carlo formalism. In particular, we couple this model with empirical constraints on the statistical spread in strength for meter-scale impactors from Brown et al (2015) based on the observed height at maximum bolide brightness. We also use the correlation of peak bolide brightness with total energy as given by Brown (2016) as a proxy for fragmentation behaviour. Using these constraints, we are able to quickly generate a large set of realizations of probable bolide energy deposition curves and produce simple estimates of expected blast damage using existing analytical relations.We validate this code with the known parameters of the Chelyabinsk airburst and explore how changes to the entry conditions of the observed bolide may have modified the blast damage at the ground. We will also present how this approach could be used in an actual short-warning impact scenario. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21384327','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21384327">Theologies, ideologies and evolutionary biology.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Scudo, Francesco M 2010-01-01 Since a century evolution has mostly been interpreted by two simple, "opposite" kinds of "theories" i.e. as due either to fitness differences among genotypes or to some other simple mechanism while bona fide, more complex theories were less popular throughout. In particular by far the most complete theories ever produced were suddenly, almost universally abandoned just after World War II, though not as a consequence of major breakthroughs. The causes of this situation are examined by analogy with much earlier developments and their demise by Cartesianism. The down to earth solutions these "complete" theories provide to the problems of "speciation" and the origins of cells are contrasted with the "miraculous" approaches by systemic neo-Darwinists. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/10335016','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/10335016">Internal and temporal reliability estimates for informant ratings of personality using the NEO PI-R and IAS. NEO Personality Inventory. Interpersonal Adjective Scales.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Kurtz, J E; Lee, P A; Sherker, J L 1999-06-01 This study examines the internal consistency and temporal stability of informant ratings from two widely used instruments for normal personality assessment, the revised NEO Personality Inventory (NEO PI-R) and the Interpersonal Adjective Scales (IAS). Well-known adult targets were selected by 109 undergraduate students and rated on two occasions separated by a 6-month interval. With few exceptions, estimates of internal consistency are adequate to good for both instruments. NEO PI-R domain scores yield coefficient alphas ranging from .89 to .96, with a median of .80 for the 30 facet scales. IAS octant scales show coefficient alphas ranging from .83 to .92. Retest Pearson correlations are above .70 for each of the NEO PI-R domain scores and both IAS axis coordinates, and intraclass correlations are above .60 for all scales from both instruments. Score changes were small but statistically significant for three of the five NEO PI-R domains at retest. The retest stability of IAS type classifications varies as a function of the extremity of the associated octant scores. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19282686','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19282686">Nineteen-month stability of Revised NEO Personality Inventory domain and facet scores in patients with personality disorders.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Wilberg, Theresa; Karterud, Sigmund; Pedersen, Geir; Urnes, Øyvind; Costa, Paul T 2009-03-01 We lack knowledge of the temporal stability of major personality dimensions in patients with personality disorders (PDs). The Revised NEO Personality Inventory (NEO-PI-R) is a self-report instrument that operationalizes the Five-Factor Model of personality. This study investigated the relative stability, mean level stability, and individual level stability of the NEO-PI-R scores in patients with PDs (n = 393) and patients with symptom disorders only (n = 131). The NEO-PI-R was administered at admission to short-term day treatment and after an average of 19 months. The results showed a moderate to high degree of stability of NEO-PI-R scale scores with no substantial difference in stability between patients with and without PD. Changes in NEO-PI-R scores were associated with changes in symptom distress. Neuroticism was the least stable domain. The study indicates that the Five-Factor Model of personality dimensions and traits are fairly stable in patients with PDs. The lower stability of Neuroticism may partly be explained by its inherent state aspects. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27609789','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27609789">68Ga/177Lu-NeoBOMB1, a Novel Radiolabeled GRPR Antagonist for Theranostic Use in Oncology.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Dalm, Simone U; Bakker, Ingrid L; de Blois, Erik; Doeswijk, Gabriela N; Konijnenberg, Mark W; Orlandi, Francesca; Barbato, Donato; Tedesco, Mattia; Maina, Theodosia; Nock, Berthold A; de Jong, Marion 2017-02-01 Because overexpression of the gastrin-releasing peptide receptor (GRPR) has been reported on various cancer types, for example, prostate cancer and breast cancer, targeting this receptor with radioligands might have a significant impact on staging and treatment of GRPR-expressing tumors. NeoBOMB1 is a novel DOTA-coupled GRPR antagonist with high affinity for GRPR and excellent in vivo stability. The purpose of this preclinical study was to further explore the use of NeoBOMB1 for theranostic application by determining the biodistribution of 68 Ga-NeoBOMB1 and 177 Lu-NeoBOMB1. PC-3 tumor-xenografted BALB/c nu/nu mice were injected with either approximately 13 MBq/250 pmol 68 Ga-NeoBOMB1 or a low (∼1 MBq/200 pmol) versus high (∼1 MBq/10 pmol) peptide amount of 177 Lu-NeoBOMB1, after which biodistribution and imaging studies were performed. At 6 time points (15, 30, 60, 120, 240, and 360 min for 68 Ga-NeoBOMB1 and 1, 4, 24, 48, 96, and 168 h for 177 Lu-NeoBOMB1) postinjection tumor and organ uptake was determined. To assess receptor specificity, additional groups of animals were coinjected with an excess of unlabeled NeoBOMB1. Results of the biodistribution studies were used to determine pharmacokinetics and dosimetry. Furthermore, PET/CT and SPECT/MRI were performed. Injection of approximately 250 pmol 68 Ga-NeoBOMB1 resulted in a tumor and pancreas uptake of 12.4 ± 2.3 and 22.7 ± 3.3 percentage injected dose per gram (%ID/g) of tissue, respectively, at 120 min after injection. 177 Lu-NeoBOMB1 biodistribution studies revealed a higher tumor uptake (17.9 ± 3.3 vs. 11.6 ± 1.3 %ID/g of tissue at 240 min after injection) and a lower pancreatic uptake (19.8 ± 6.9 vs. 105 ± 13 %ID/g of tissue at 240 min after injection) with the higher peptide amount injected, leading to a significant increase in the absorbed dose to the tumor versus the pancreas (200 pmol, 570 vs. 265 mGy/MBq; 10 pmol, 435 vs. 1393 mGy/MBq). Using these data to predict patient dosimetry, we found a kidney, pancreas, and liver exposure of 0.10, 0.65, and 0.06 mGy/MBq, respectively. Imaging studies resulted in good visualization of the tumor with both 68 Ga-NeoBOMB1 and 177 Lu-NeoBOMB1. Our findings indicate that 68 Ga- or 177 Lu-labeled NeoBOMB1 is a promising radiotracer with excellent tumor uptake and favorable pharmacokinetics for imaging and therapy of GRPR-expressing tumors. © 2017 by the Society of Nuclear Medicine and Molecular Imaging. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110022601','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110022601">Why Atens Enjoy Enhanced Accessibility for Human Space Flight</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Barbee, Brent W.; Adamo, Daniel R. 2011-01-01 Near-Earth objects can be grouped into multiple orbit classifications, among them being the Aten group, whose members have orbits crossing Earth's with semi-major axes less than 1 astronomical unit. Atens comprise well under 10% of known near-Earth objects. This is in dramatic contrast to results from recent human space flight near-Earth object accessibility studies, where the most favorable known destinations are typically almost 50% Atens. Geocentric dynamics explain this enhanced Aten accessibility and lead to an understanding of where the most accessible near-Earth objects reside. Without a comprehensive space-based survey, however, highly accessible Atens will remain largely unknown. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29150608','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29150608">Rapid neo-sex chromosome evolution and incipient speciation in a major forest pest.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Bracewell, Ryan R; Bentz, Barbara J; Sullivan, Brian T; Good, Jeffrey M 2017-11-17 Genome evolution is predicted to be rapid following the establishment of new (neo) sex chromosomes, but it is not known if neo-sex chromosome evolution plays an important role in speciation. Here we combine extensive crossing experiments with population and functional genomic data to examine neo-XY chromosome evolution and incipient speciation in the mountain pine beetle. We find a broad continuum of intrinsic incompatibilities in hybrid males that increase in strength with geographic distance between reproductively isolated populations. This striking progression of reproductive isolation is coupled with extensive gene specialization, natural selection, and elevated genetic differentiation on both sex chromosomes. Closely related populations isolated by hybrid male sterility also show fixation of alternative neo-Y haplotypes that differ in structure and male-specific gene content. Our results suggest that neo-sex chromosome evolution can drive rapid functional divergence between closely related populations irrespective of ecological drivers of divergence. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25809956','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25809956">Effect of Slip Time in Forming Neo-Esophageal Stenosis After Replacement of a Thoracic Esophagus With Nitinol Artificial Esophagus.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Liang, Xian-Liang; Liang, Jian-Hui 2015-07-01 Attempts have been made to investigate the effect of slip time of nitinol artificial esophagus for forming neo-esophageal stenosis after replacement of a thoracic esophagus with nitinol artificial esophagus in 20 experimental pigs. The pigs whose slip time was less than 90 days postoperatively had severe dysphagia (Bown's III) immediately after they were fed, and the dysphagia aggravated gradually later on (Bown's III-IV). The pigs whose slip time was more than 90 days postoperatively had mild/moderate dysphagia (Bown's I-II) immediately after they were fed, and the dysphagia relieved gradually later on (Bown's II-I-0). The ratios between the diameter of neo-esophagus in different slip time and normal esophagus were 25% (at 2 months postoperatively), 58% (at 4 months postoperatively), and 93% (at 6 months postoperatively), respectively. The relationship between nitinol artificial esophagus slip time and neo-esophageal stenosis showed a positive correlation. After replacement of a thoracic esophagus with nitinol artificial esophagus, the artificial esophageal slip time not only affected the original diameter of the neo-esophagus immediately, but also affected the neo-esophageal scar stricture forming process later on. The narrowing of neo-esophagus is caused by overgrowth of scar tissue. But there is the positive correlation between artificial esophagus slip time and neo-esophageal stenosis, so this can be a way of overcoming neo-esophageal stenosis by delaying slip time of artificial esophagus. Copyright © 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11934798','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11934798">Neostigmine interactions with non steroidal anti-inflammatory drugs.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Miranda, Hugo F; Sierralta, Fernando; Pinardi, Gianni 2002-04-01 1. The common mechanism of action of non-steroidal anti-inflammatory drugs (NSAIDs) is the inhibition of the enzyme cyclo-oxygenase (COX), however, this inhibition is not enough to completely account for the efficacy of these agents in several models of acute pain. 2. It has been demonstrated that cholinergic agents can induce antinociception, but the nature of the interaction between these agents and NSAIDs drugs has not been studied. The present work evaluates, by isobolographic analysis, the interactions between the cholinergic indirect agonist neostigmine (NEO) and NSAIDs drugs, using a chemical algesiometric test. 3. Intraperitoneal (i.p.) or intrathecal (i.t.) administration of NEO and of the different NSAIDs produced dose-dependent antinociception in the acetic acid writhing test of the mouse. 4. The i.p. or i.t. co-administration of fixed ratios of ED(50) fractions of NSAIDs and NEO, resulted to be synergistic or supra-additive for the combinations ketoprofen (KETO) and NEO, paracetamol (PARA) and NEO) and diclofenac (DICLO) and NEO administered i.p. However, the same combinations administered i.t. were only additive. In addition, the combinations meloxicam (MELO) and NEO and piroxicam (PIRO) and NEO, administered either i.p. or i.t., were additive. 5. The results suggest that the co-administration of NEO with some NSAIDs (e.g. KETO, PARA or DICLO) resulted in a synergistic interaction, which may provide evidence of supraspinal antinociception modulation by the increased acetylcholine concentration in the synaptic cleft of cholinergic interneurons. The interaction obtained between neostigmine and the NSAIDs could carry important clinical implications. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3332171','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3332171">Development and Validation of a Personality Assessment Instrument for Traditional Korean Medicine: Sasang Personality Questionnaire</a> <a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Chae, Han; Lee, Siwoo; Park, Soo Hyun; Jang, Eunsu; Lee, Soo Jin 2012-01-01 Objective. Sasang typology is a traditional Korean medicine based on the biopsychosocial perspectives of Neo-Confucianism and utilizes medical herbs and acupuncture for type-specific treatment. This study was designed to develop and validate the Sasang Personality Questionnaire (SPQ) for future use in the assessment of personality based on Sasang typology. Design and Methods. We selected questionnaire items using internal consistency analysis and examined construct validity with explorative factor analysis using 245 healthy participants. Test-retest reliability as well as convergent validity were examined. Results. The 14-item SPQ showed acceptable internal consistency (Cronbach's alpha = .817) and test-retest reliability (r = .837). Three extracted subscales, SPQ-behavior, SPQ-emotionality, and SPQ-cognition, were found, explaining 55.77% of the total variance. The SPQ significantly correlated with Temperament and Character Inventory novelty seeking (r = .462), harm avoidance (r = −.390), and NEO Personality Inventory extraversion (r = .629). The SPQ score of the So-Eum (24.43 ± 4.93), Tae-Eum (27.33 ± 5.88), and So-Yang (30.90 ± 5.23) types were significantly different from each other (P < .01). Conclusion. Current results demonstrated the reliability and validity of the SPQ and its subscales that can be utilized as an objective instrument for conducting personalized medicine research incorporating the biopsychosocial perspective. PMID:22567034 </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29704236','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29704236">Are reflective models appropriate for very short scales? Proofs of concept of formative models using the Ten-Item Personality Inventory.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Myszkowski, Nils; Storme, Martin; Tavani, Jean-Louis 2018-04-27 Because of their length and objective of broad content coverage, very short scales can show limited internal consistency and structural validity. We argue that it is because their objectives may be better aligned with formative investigations than with reflective measurement methods that capitalize on content overlap. As proofs of concept of formative investigations of short scales, we investigate the Ten Item Personality Inventory (TIPI). In Study 1, we administered the TIPI and the Big Five Inventory (BFI) to 938 adults, and fitted a formative Multiple Indicator Multiple Causes model, which consisted of the TIPI items forming 5 latent variables, which in turn predicted the 5 BFI scores. These results were replicated in Study 2, on a sample of 759 adults, with, this time, the Revised NEO Personality Inventory (NEO-PI-R) as the external criterion. The models fit the data adequately, and moderate to strong significant effects (.37<|β|<.69, all p<.001) of all 5 latent formative variables on their corresponding BFI and NEOPI-R scores were observed. This study presents a formative approach that we propose to be more consistent with the aims of scales with broad content and short length like the TIPI. This article is protected by copyright. All rights reserved. © 2018 Wiley Periodicals, Inc. </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active">23</li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active">24</li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20180002607','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20180002607">Project NEO Specific Impulse Testing Solutions</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Baffa, Bill 2018-01-01 The Neo test stand is currently configured to fire a horizontally mounted rocket motor with up to 6500 lbf thrust. Currently, the Neo test stand can measure flow of liquid propellant and oxidizer, pressures residing in the closed system up to the combustion chamber. The current configuration does not have the ability to provide all data needed to compute specific impulse. This presents three methods to outfit the NEO test fixture with instrumentation allowing for calculation of specific impulse. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA447839','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA447839">In Vivo Imaging of mdrla Gene Expression</a> <a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a> 2005-06-01 svImJ mouse strain, compatible with the ES cells used in our Transgenic Mouse Facility. b. Engineer PGK-neo and Renilla luciferase cassettes...inserted between the two loxP sites, upstream of the Neo cassette. A cloning strategy was then devised to fuse Renilla luciferase in-frame with the...sites: B, BamHI; E, EcoRI; S, ScaI. PGK-neo: neo under the control of the PGK promoter. Luc: Renilla luciferase fused in- frame with the translated </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA474424','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA474424">On NEO Threat Mitigation (Preprint)</a> <a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a> 2007-10-15 Yucatan event is at least a major contributor, if not the direct cause of the extinction of the dinosaurs . Moreover, it is clear that NEO impacts can... extinction of the human race. The probability of these events decreases with the severity of the impact, and size (mass) of the NEO. Figure 1 and Table 1...thus, it is more reasonable to infer that all the large NEOs can be catalogued within a reasonable time, while smaller and less consequential </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150002915','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150002915">Investigating Trojan Asteroids at the L4/L5 Sun-Earth Lagrange Points</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> John, K. K.; Graham, L. D.; Abell, P. A. 2015-01-01 Investigations of Earth's Trojan asteroids will have benefits for science, exploration, and resource utilization. By sending a small spacecraft to the Sun-Earth L4 or L5 Lagrange points to investigate near-Earth objects, Earth's Trojan population can be better understood. This could lead to future missions for larger precursor spacecraft as well as human missions. The presence of objects in the Sun-Earth L4 and L5 Lagrange points has long been suspected, and in 2010 NASA's Wide-field Infrared Survey Explorer (WISE) detected a 300 m object. To investigate these Earth Trojan asteroid objects, it is both essential and feasible to send spacecraft to these regions. By exploring a wide field area, a small spacecraft equipped with an IR camera could hunt for Trojan asteroids and other Earth co-orbiting objects at the L4 or L5 Lagrange points in the near-term. By surveying the region, a zeroth-order approximation of the number of objects could be obtained with some rough constraints on their diameters, which may lead to the identification of potential candidates for further study. This would serve as a precursor for additional future robotic and human exploration targets. Depending on the inclination of these potential objects, they could be used as proving areas for future missions in the sense that the delta-V's to get to these targets are relatively low as compared to other rendezvous missions. They can serve as platforms for extended operations in deep space while interacting with a natural object in microgravity. Theoretically, such low inclination Earth Trojan asteroids exist. By sending a spacecraft to L4 or L5, these likely and potentially accessible targets could be identified. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910012283','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910012283">Report of the panel on earth rotation and reference frames, section 7</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Dickey, Jean O.; Dickman, Steven R.; Eubanks, Marshall T.; Feissel, Martine; Herring, Thomas A.; Mueller, Ivan I.; Rosen, Richard D.; Schutz, Robert E.; Wahr, John M.; Wilson, Charles R. 1991-01-01 Objectives and requirements for Earth rotation and reference frame studies in the 1990s are discussed. The objectives are to observe and understand interactions of air and water with the rotational dynamics of the Earth, the effects of the Earth's crust and mantle on the dynamics and excitation of Earth rotation variations over time scales of hours to centuries, and the effects of the Earth's core on the rotational dynamics and the excitation of Earth rotation variations over time scales of a year or longer. Another objective is to establish, refine and maintain terrestrial and celestrial reference frames. Requirements include improvements in observations and analysis, improvements in celestial and terrestrial reference frames and reference frame connections, and improved observations of crustal motion and mass redistribution on the Earth. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27493272','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27493272">Theranostic Perspectives in Prostate Cancer with the Gastrin-Releasing Peptide Receptor Antagonist NeoBOMB1: Preclinical and First Clinical Results.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Nock, Berthold A; Kaloudi, Aikaterini; Lymperis, Emmanouil; Giarika, Athina; Kulkarni, Harshad R; Klette, Ingo; Singh, Aviral; Krenning, Eric P; de Jong, Marion; Maina, Theodosia; Baum, Richard P 2017-01-01 We recently introduced the potent gastrin-releasing peptide receptor (GRPR) antagonist 68 Ga-SB3 ( 68 Ga-DOTA-p-aminomethylaniline-diglycolic acid-DPhe-Gln-Trp-Ala-Val-Gly-His-Leu-NHEt), showing excellent tumor localizing efficacy in animal models and in patients. By replacement of the C-terminal Leu 13 -Met 14 -NH 2 dipeptide of SB3 by Sta 13 -Leu 14 -NH 2 , the novel GRPR antagonist NeoBOMB1 was generated and labeled with different radiometals for theranostic use. We herein report on the biologic profile of resulting 67/68 Ga-, 111 In-, and 177 Lu-NeoBOMB1 radioligands in GRPR-expressing cells and mouse models. The first evidence of prostate cancer lesion visualization in men using 68 Ga-NeoBOMB1 and PET/CT is also presented. NeoBOMB1 was radiolabeled with 67/68 Ga, 111 In, and 177 Lu according to published protocols. The respective metalated species nat Ga-, nat In-, and nat Lu-NeoBOMB1 were also synthesized and used in competition binding experiments against [ 125 I-Tyr 4 ]BBN in GRPR-positive PC-3 cell membranes. Internalization of 67 Ga-, 111 In-, and 177 Lu-NeoBOMB1 radioligands was studied in PC-3 cells at 37°C, and their metabolic stability in peripheral mouse blood was determined by high-performance liquid chromatography analysis of blood samples. Biodistribution was performed by injecting a 67 Ga-, 111 In-, or 177 Lu-NeoBOMB1 bolus (74, 74, or 370 kBq, respectively, 100 μL, 10 pmol total peptide ± 40 nmol Tyr 4 -BBN: for in vivo GRPR blockade) in severe combined immunodeficiency mice bearing PC-3 xenografts. PET/CT images with 68 Ga-NeoBOMB1 were acquired in prostate cancer patients. NeoBOMB1 and nat Ga-, nat In-, and nat Lu-NeoBOMB1 bound to GRPR with high affinity (half maximal inhibitory concentration, 1-2 nM). 67 Ga-, 111 In-, and 177 Lu-NeoBOMB1 specifically and strongly bound on the cell membrane of PC-3 cells displaying low internalization, as expected for receptor antagonists. They showed excellent metabolic stability in peripheral mouse blood (>95% intact at 5 min after injection). After injection in mice, all 3 ( 67 Ga-, 111 In-, and 177 Lu-NeoBOMB1) showed comparably high and GRPR-specific uptake in the PC-3 xenografts (e.g., 30.6 ± 3.9, 28.6 ± 6.0, and >35 percentage injected dose per gram at 4 h after injection, respectively), clearing from background predominantly via the kidneys. During a translational study in prostate cancer patients, 68 Ga-NeoBOMB1 rapidly localized in pathologic lesions, achieving high-contrast imaging. The GRPR antagonist radioligands 67 Ga-, 111 In-, and 177 Lu-NeoBOMB1, independent of the radiometal applied, have shown comparable behavior in prostate cancer models, in favor of future theranostic use in GRPR-positive cancer patients. Such translational prospects were further supported by the successful visualization of prostate cancer lesions in men using 68 Ga-NeoBOMB1 and PET/CT. © 2017 by the Society of Nuclear Medicine and Molecular Imaging. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4788350','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4788350">Safety Evaluation of Neo Transgenic Pigs by Studying Changes in Gut Microbiota Using High-Throughput Sequencing Technology</a> <a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Jiang, Shengwang; Cai, Chunbo; Ma, Dezun; Gao, Pengfei; Li, Hegang; Jiang, Ke; Tang, Maoxue; Hou, Jian; Liu, Jie; Cui, Wentao 2016-01-01 The neo (neomycin phosphotransferase) gene is widely used as a selection marker in the production of genetically engineered animals and plants. Recent attention has been focused on safety concerns regarding neo transgene expression. In this study, neo transgenic and non-transgenic piglets were randomly assigned into Group A and Group B to evaluate effects of neo transgene by studying changes in gut microbiota using high-throughput sequencing. Group A pigs were fed a standard diet supplemented with antibiotic neomycin; Group B pigs were fed a standard diet. We examined horizontal transfer of exogenous neo gene using multiplex PCR; and investigated if the presence of secreted NPT II (neo expression product) in the intestine could lead to some protection against neomycin in transgenic pigs by monitoring different patterns of changes in gut microbiota in Group A animals. The unintended effects of neo transgene on gut microbiota were studied in Group B animals. Horizontal gene transfer was not detected in gut microbiota of any transgenic pigs. In Group A, a significant difference was observed between transgenic pigs and non-transgenic pigs in pattern of changes in Proteobacteria populations in fecal samples during and post neomycin feeding. In Group B, there were significant differences in the relative abundance of phyla Firmicutes, Bacteroidetes and Proteobacteria, and genera Lactobacillus and Escherichia-Shigella-Hafnia between transgenic pigs and non-transgenic pigs. We speculate that the secretion of NPT II from transgenic tissues/cells into gut microbiota results in the inhibition of neomycin activity and the different patterns of changes in bacterial populations. Furthermore, the neo gene also leads to unintended effects on gut microbiota in transgenic pigs that were fed with basic diet (not supplemented with neomycin). Thus, our data in this study caution that wide use of the neo transgene in genetically engineered animals should be carefully considered and fully assessed. PMID:26966911 </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4150571','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4150571">Aesthetic neo-glans reconstruction after penis-sparing surgery for benign, premalignant or malignant penile lesions</a> <a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Palminteri, Enzo; Fusco, Fernando; Berdondini, Elisa; Salonia, Andrea 2011-01-01 Purpose To describe the technique and results of penis-sparing surgery combined with a cosmetic neo-glans reconstruction for benign, pre-malignant or malignant penile lesions. Patients and methods Twenty-one patients (mean age 61 years) with penile lesions with a broad spectrum of histopathology underwent organ-sparing surgery with neo-glans reconstruction, using a free split-thickness skin graft harvested from the thigh. Three patients were treated by glans-skinning and glans-resurfacing, 10 by glansectomy and neo-glans reconstruction, four by partial penectomy and a neo-glans reconstruction, and four by neo-glans reconstruction after a traditional partial penectomy. Results The mean follow-up was 45 months; all patients were free of primary local disease. All patients were satisfied with the appearance of the penis after surgery, and recovered their sexual ability, although sensitivity was reduced as a consequence of glans/penile amputation. Conclusion In benign, premalignant or malignant penile lesions, penis-sparing surgery combined with a cosmetic neo-glans reconstruction can be used to assure a normally appearing and functional penis, while fully eradicating the primary local disease. PMID:26579279 </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11172584','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11172584">Assessing adolescents' personality with the NEO PI-R.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> De Fruyt, F; Mervielde, I; Hoekstra, H A; Rolland, J P 2000-12-01 The suitability of the Revised NEO Personality Inventory (NEO PI-R) to assess adolescents' personality traits was investigated in an unselected heterogeneous sample of 469 adolescents aged 12 to 17 years. They were further administered the Hierarchical Personality Inventory for Children (HiPIC) to allow an examination of convergent and discriminant validity. The adult NEO PI-R factor structure proved to be highly replicable in the sample of adolescents, with all facet scales primarily loading on the expected factors, independent of the age group. Domain and facet internal consistency coefficients were comparable to those obtained in adult samples, with less than 12% of the items showing corrected item-facet correlations below absolute value .20. Although, in general, adolescents reported few difficulties with the comprehensibility of the items, they tend to report more problems with the Openness to Ideas (05) and Openness to Values (06) items. Correlations between NEO PI-R and HiPIC scales underscored the convergent and discriminant validity of the NEO facets and HiPIC scales. It was concluded that the NEO PI-R in its present form is useful for assessing adolescents' traits at the primary level, but additional research is necessary to infer the most appropriate facet level structure. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=Mahoney&pg=4&id=EJ378532','ERIC'); return false;" href="https://eric.ed.gov/?q=Mahoney&pg=4&id=EJ378532">A Neo-Cognitive Dimension.</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Suarez, E. M. 1988-01-01 Responds to Mahoney and Lyddon's review of constructivism in previous article by focusing on developments emerged from work with Neo-Cognitive Psychotherapy that add new and necessary dimension to issues of agency and constructivism. Presents neo-cognitive view of thought and discusses the evolution of understanding. (NB) </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29137400','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29137400">Downregulation of the Sonic Hedgehog/Gli pathway transcriptional target Neogenin-1 is associated with basal cell carcinoma aggressiveness.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Casas, Bárbara S; Adolphe, Christelle; Lois, Pablo; Navarrete, Nelson; Solís, Natalia; Bustamante, Eva; Gac, Patricio; Cabané, Patricio; Gallegos, Ivan; Wainwright, Brandon J; Palma, Verónica 2017-10-13 Basal Cell Carcinoma (BCC) is one of the most diagnosed cancers worldwide. It develops due to an unrestrained Sonic Hedgehog (SHH) signaling activity in basal cells of the skin. Certain subtypes of BCC are more aggressive than others, although the molecular basis of this phenomenon remains unknown. We have previously reported that Neogenin-1 (NEO1) is a downstream target gene of the SHH/GLI pathway in neural tissue. Given that SHH participates in epidermal homeostasis, here we analyzed the epidermal expression of NEO1 in order to identify whether it plays a role in adult epidermis or BCC. We describe the mRNA and protein expression profile of NEO1 and its ligands (Netrin-1 and RGMA) in human and mouse control epidermis and in a broad range of human BCCs. We identify in human BCC a significant positive correlation in the levels of NEO1 receptor, NTN-1 and RGMA ligands with respect to GLI1 , the main target gene of the canonical SHH pathway. Moreover, we show via cyclopamine inhibition of the SHH/GLI pathway of ex vivo cultures that NEO1 likely functions as a downstream target of SHH/GLI signaling in the skin. We also show how Neo1 expression decreases throughout BCC progression in the K14-Cre:Ptch1 lox/lox mouse model and that aggressive subtypes of human BCC exhibit lower levels of NEO1 than non-aggressive BCC samples. Taken together, these data suggest that NEO1 is a SHH/GLI target in epidermis. We propose that NEO1 may be important in tumor onset and is then down-regulated in advanced BCC or aggressive subtypes. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5663572','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5663572">Downregulation of the Sonic Hedgehog/Gli pathway transcriptional target Neogenin-1 is associated with basal cell carcinoma aggressiveness</a> <a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Casas, Bárbara S.; Adolphe, Christelle; Lois, Pablo; Navarrete, Nelson; Solís, Natalia; Bustamante, Eva; Gac, Patricio; Cabané, Patricio; Gallegos, Ivan; Wainwright, Brandon J.; Palma, Verónica 2017-01-01 Basal Cell Carcinoma (BCC) is one of the most diagnosed cancers worldwide. It develops due to an unrestrained Sonic Hedgehog (SHH) signaling activity in basal cells of the skin. Certain subtypes of BCC are more aggressive than others, although the molecular basis of this phenomenon remains unknown. We have previously reported that Neogenin-1 (NEO1) is a downstream target gene of the SHH/GLI pathway in neural tissue. Given that SHH participates in epidermal homeostasis, here we analyzed the epidermal expression of NEO1 in order to identify whether it plays a role in adult epidermis or BCC. We describe the mRNA and protein expression profile of NEO1 and its ligands (Netrin-1 and RGMA) in human and mouse control epidermis and in a broad range of human BCCs. We identify in human BCC a significant positive correlation in the levels of NEO1 receptor, NTN-1 and RGMA ligands with respect to GLI1, the main target gene of the canonical SHH pathway. Moreover, we show via cyclopamine inhibition of the SHH/GLI pathway of ex vivo cultures that NEO1 likely functions as a downstream target of SHH/GLI signaling in the skin. We also show how Neo1 expression decreases throughout BCC progression in the K14-Cre:Ptch1lox/lox mouse model and that aggressive subtypes of human BCC exhibit lower levels of NEO1 than non-aggressive BCC samples. Taken together, these data suggest that NEO1 is a SHH/GLI target in epidermis. We propose that NEO1 may be important in tumor onset and is then down-regulated in advanced BCC or aggressive subtypes. PMID:29137400 </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.T52A..05V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.T52A..05V">Jurassic subduction initiation in the western and central Neo-Tethys and the origin of the Balkan ophiolites</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Van Hinsbergen, D. J. J.; Maffione, M. 2017-12-01 Jurassic subduction initiation in the Neo-Tethys Ocean was the first, critical step of a long tectonic process that eventually led to the collision of the Adria-Africa and Eurasia plates and the formation of a 6000 km long Alpine orogenic belt spanning from the Balkan Peninsula to Iran. Investigating the process of subduction initiation in the Neo-Tethys during the Jurassic is crucial to (i) reconstruct the complex geological evolution of this orogen from its initial stages, and (ii) shed new lights over the enigmatic kinematics and driving mechanisms of subduction initiation. Records of the initial closure of the Neo-Tethys are today preserved in a fragmented belt of Middle Jurassic ophiolites (170-160 Ma) distributed above the Alpine orogen. In particular, the well-preserved and extensively studied ophiolites of the Balkan Peninsula offer a unique chance to study the mechanisms leading to the closure of the western domain of the Neo-Tethys. Here we provide the first quantitative constraints on the geometry of the Jurassic Neo-Tethyan subduction system using a net tectonic rotation analysis based on paleomagnetic and structural geological data from the sheeted dyke complexes of various ophiolites of Serbia (Maljen, Ibar) and Greece (Othris, Pindos, Vourinos, Guevgueli). Our results show that closure of the western Neo-Tethys was accommodated by two subduction zones, one intra-oceanic, formed at the N-S trending Neo-Tethyan ridge, the other initiated at the European passive margin and curving southward from a N-S to a NW-SE direction following the shape of the passive margin. We propose that these two subduction zones formed upon propagation of subduction(s) initiated in the central Neo-Tethys (modern Turkey) in the late Early Jurassic ( 185-180 Ma). </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050165117','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050165117">Compositional Investigation of Binary Near-Earth Asteroid 66063 (1998 RO1): A Potentially Undifferentiated Assemblage</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Abell, P. A.; Gaffey, M. J.; Landis, R. R.; Jarvis, K. S. 2005-01-01 It is now thought that approximately 16% of all asteroids among the near-Earth population may be binary objects. Several independent lines of evidence, such as the presence of doublet craters on the Earth and Moon [1, 2], complex lightcurves of near-Earth objects exhibiting mutual events [3], and radar images of near-Earth asteroids revealing distinct primary and secondary objects, have supported this conclusion [4]. To date at least 23 near-Earth objects have been discovered as binary systems with expectations that many more have yet to be identified or recognized. Little is known about the physical characteristics of binary objects except that they seem to have fairly rapid rotation rates, generally have primaries in the approx. 1 km diameter range with smaller secondaries on the order of a few hundred meters, and apart from a few exceptions, are in synchronous orbits [4, 5]. Previously only two of these binary near-Earth asteroids (1998 ST27 and 2003 YT1) have been characterized in terms of detailed mineralogical investigations [6, 7]. Such investigations are required to fully understand the formation mechanisms of these binary objects and their possible source regions. In addition, detailed knowledge of these objects may play an important role for planning future spacecraft missions and for the development of impact mitigation strategies. The work presented here represents a continued effort to characterize this particular sub-group of the near- Earth asteroid population. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2013-06-26/pdf/2013-15302.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2013-06-26/pdf/2013-15302.pdf">78 FR 38430 - Culturally Significant Objects Imported for Exhibition; Determinations: “Of Heaven and Earth: 500...</a> <a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a> 2013-06-26 ... DEPARTMENT OF STATE [Public Notice 8359] Culturally Significant Objects Imported for Exhibition; Determinations: ``Of Heaven and Earth: 500 Years of Italian Painting From Glasgow Museums'' SUMMARY: Notice is... objects to be included in the exhibition ``Of Heaven and Earth: 500 Years of Italian Painting from Glasgow... </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2013-08-07/pdf/2013-19086.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2013-08-07/pdf/2013-19086.pdf">78 FR 48216 - Culturally Significant Objects Imported for Exhibition Determinations: “Heaven and Earth: Art of...</a> <a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a> 2013-08-07 ... DEPARTMENT OF STATE [Public Notice 8412] Culturally Significant Objects Imported for Exhibition Determinations: ``Heaven and Earth: Art of Byzantium from Greek Collections'' SUMMARY: Notice is hereby given of... determine that the objects to be included in the exhibition ``Heaven and Earth: Art of Byzantium from Greek... </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002cosp...34E1796F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002cosp...34E1796F">Planetary protection - some legal questions</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Fasan, E. When we legally investigate the topic of Planetary Protection, we have to realise that there are primarily two very distinct parts of our juridical work: We have to study lex lata, the existing applicable Law, especially Space Law, and also lex ferenda, what should be the law. With this in mind, we have to deliberate the legal meaning of "Planetary", and of "Protection". About "Planetary": Our own Earth is the most important planet. At present only here do exist human beings, who are sensu strictu the only legal subjects. We make the law, we have to apply it, and we are to be protected as well as bound by it. Then, we have to discuss what is further meant by "Planetary": Is it planets in an astronomical sense only, the nine planets which revolve around our fixed star, namely the sun, or is it also satellites, moving around most of these planets, as our own Moon circles Earth. "The Moon and other Celestial Bodies (C.B)" are subject to Space Law, especially to International Treaties, Agreements, Resolutions of the UN etc. I propose that they and not only the planets in an strictly astronomical sense are to be protected. But I do not think that the said notion also comprises asteroids, comets, meteorites etc. although they too belong to our solar system. Our investigation comes to the result that such bodies have a different (lesser) legal quality. Also we have to ask Protection from what? From: Natural bodies - Meteorites, NEO Asteroids, Comets which could hit Earth or C.B. Artificial Objects: Space Debris threatening especially Earth and near Earth orbits. Terrestrial Life - no infection of other celestial bodies. Alien life forms which could bring about "harmful contamination" of Earth and the life, above all human life, there etc. Here, astrobiological questions have to be discussed. Special realms on C.B. which should be protected from Electronic "Noise" such as craters SAHA or Deadalus on the Moon, also taking into account the "Common Heritage" Principle. Then we have to examine: Protection where, of whom and of what: On Earth: Humans, other life forms, but also all man made things as well as air, water, soil. On Other celestial bodies: Crew of manned Space Missions, Stations on C.B., possible alien life forms, or remnants of such, water, other environment on C.B.- even if completely barren? Protection of C.B. from becoming "an area of international conflict" Finally we have to discuss overriding interests, such as deflection of Asteroids which threaten to hit Earth, then the legally permitted "Use" of C.B., also mining versus protection, and too high costs of absolutely sterile Spacecraft etc. With this we have de lege ferenda to create an order of values of protection as follows, whereby the protection of the higher category has priority over the lesser ones: 1)Human life, be it on Earth or beyond it, 2)Other terrestrial life, 3)Inanimate terrestrial environment, 4)Possible life forms or their remnants on the Moon or other C.B., 5)The natural environment of the Moon and other C.B., 6)Asteroids, Meteorites, Comets etc. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17469438','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17469438">Neo-phalloplasty with re-innervated latissimus dorsi free flap: a functional study of a novel technique.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Ranno, R; Veselý, J; Hýza, P; Stupka, I; Justan, I; Dvorák, Z; Monni, N; Novák, P; Ranno, S 2007-01-01 Twenty two patients with gender dysphoria underwent neo-phalloplasties using a novel technique. Latissimus dorsi musculocutaneus re-innervated free flap was used to allow voluntary rigidity of the neo-penis. From the first 22 patients, 18 have obtained motoric function of reconstructed penis; the "paradox erection" was obtained. 14 patients came for examination after a follow-up period of mean 26.4 months. We evaluated the motility and shape changes of neo-phallus measuring its different size and dimension during relax and muscle contraction. The range of neo-phallus length in relaxed position was between 7 and 17 cm (mean 12.2 cm), its circumference in the same position had a range between 13 and 20 cm (mean 13.7 cm). All patients were able to contract the muscle with an average length reduction of 3.08 cm and an average circumference enlargement of 4 cm. In this study, the dimensions and motility were quantified demonstrating the neo-phallus function and size changes during sexual intercourse. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11339796','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11339796">Predicting dimensions of personality disorder from domains and facets of the Five-Factor Model.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Reynolds, S K; Clark, L A 2001-04-01 We compared the utility of several trait models for describing personality disorder in a heterogeneous clinical sample (N = 94). Participants completed the Schedule for Nonadaptive and Adaptive Personality (SNAP; Clark, 1993b), a self-report measure that assesses traits relevant to personality disorder, and two measures of the Five-Factor Model: the Revised NEO Personality Inventory (NEO-PI-R; Costa and McCrae, 1992) and the Big Five Inventory (BFI; John, Donahue, & Kentle, 1991). Regression analyses indicated substantial overlap between the SNAP scales and the NEO-PI-R facets. In addition, use of the NEO-PI-R facets afforded substantial improvement over the Five-Factor Model domains in predicting interview-based ratings of DSM-IV personality disorder (American Psychiatric Association, 1994), such that the NEO facets and the SNAP scales demonstrated roughly equivalent levels of predictive power. Results support assessment of the full range of NEO-PI-R facets over the Five-Factor Model domains for both research and clinical use. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2891100','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2891100">Properties of the Products Formed by the Activity of Serum Opacity Factor against Human Plasma High Density Lipoproteins</a> <a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Pownall, Henry J.; Courtney, Harry S.; Gillard, Baiba K.; Massey, John B. 2010-01-01 Serum opacity factor from Streptococcus pyogenes transfers the cholesteryl esters (CE) of ~100,000 plasma high density lipoprotein particles (HDL) to a CE-rich microemulsion (CERM) while forming neo HDL, a cholesterol-poor HDL-like particle. HDL, neo HDL, and CERM are distinct. Neo HDL is lower in free cholesterol and has lower surface and total microviscosities than HDL; the surface polarity of neo HDL and HDL are similar. CERM is much larger than HDL and richer in cholesterol and CE. Although the surface microviscosity of HDL is higher than that of CERM, they have similar total microviscosities because cholesterol partitions into the neutral lipid core. Because of its unique surface properties apo E preferentially associates with the CERM. In contrast, the composition and properties of neo HDL make it a potential acceptor of cellular cholesterol and its esterification. Thus, neo HDL and CERM are possible vehicles for improving cholesterol transport to the liver. PMID:18838065 </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active">24</li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active">25</li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014Tectp.621..132S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014Tectp.621..132S">Petrology and geochemistry of mafic magmatic rocks from the Sarve-Abad ophiolites (Kurdistan region, Iran): Evidence for interaction between MORB-type asthenosphere and OIB-type components in the southern Neo-Tethys Ocean</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Saccani, Emilio; Allahyari, Khalil; Rahimzadeh, Bahman 2014-05-01 The Sarve-Abad (Sawlava) ophiolites crop out in the Main Zagros Thrust Zone and represent remnants of the Mesozoic southern Neo-Tethys Ocean that was located between the Arabian shield and Sanandaj-Sirjan continental block. They consist of several incomplete ophiolitic sequences including gabbroic bodies, a dyke complex, and pillow lava sequences. These rocks generally range from sub-alkaline to transitional character. Mineral chemistry and whole-rock geochemistry indicate that they have compositions akin to enriched-type mid-ocean ridge basalts (E-MORB) and plume-type MORB (P-MORB). Nonetheless, the different depletion degrees in heavy rare earth elements (HREE), which can be observed in both E-MORB like and P-MORB like rocks enable two main basic chemical types of rocks to be distinguished as Type-I and Type-II. Type-I rocks are strongly depleted in HREE (YbN < ~ 6), whereas Type-II rocks are moderately depleted in HREE (YbN > 9.0). Petrogenetic modeling shows that Type-I rocks originated from 7 to 16% polybaric partial melting of a MORB-type mantle source, which was significantly enriched by plume-type components. These rocks resulted from the mixing of variable fractions of melts generated in garnet-facies and the spinel-facies mantle. In contrast, Type-II rocks originated from 5 to 8% partial melting in the spinel-facies of a MORB-type source, which was moderately enriched by plume-type components. A possible tectono-magmatic model for the generation of the southern Neo-Tethys oceanic crust implies that the continental rift and subsequent oceanic spreading were associated with uprising of MORB-type asthenospheric mantle featuring plume-type component influences decreasing from deep to shallow mantle levels. These deep plume-type components were most likely inherited from Carboniferous mantle plume activity that was associated with the opening of Paleo-Tethys in the same area. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014acm..conf..463S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014acm..conf..463S">Cohesion, granular solids, granular liquids, and their connection to small near-Earth objects</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Sánchez, P.; Scheeres, D. 2014-07-01 During the last 15 years or so, the Planetary Sciences community has been using Discrete Element Method (DEM) simulation codes to study small near-Earth objects (NEOs). In general, these codes treat gravitational aggregates as conglomerates of spherical particles; a good approximation given that many asteroids are self-gravitating granular media. Unfortunately, the degree of sophistication of these codes, and our own understanding, has not been high enough as to appropriately represent realistic physical properties of granular matter. In particular, angles of friction (θ) and cohesive strength (σ_c) of the aggregates were rarely taken in consideration and this could have led to unrealistic dynamics, and therefore, unrealistic conclusions about the dynamical evolution of small NEOs. In our research, we explore the failure mechanics of spherical (r=71 m) and ellipsoidal (r_1=92 m) self-gravitating aggregates with different angles of friction and values for their cohesive strength, in order to better understand the geophysics of rubble-pile asteroids. In particular we focused on the deformation and different disruption modes provoked by an always increasing angular velocity (spin rate). Scaling arguments allow us to regard simulations with the same aggregate size and different σ_c as equivalent to simulations of aggregates of different size and the same σ_c. We use a computational code that implements a Soft-Sphere DEM. The aggregates are composed by 3,000 spherical solid spheres (7--10 m) with 6 degrees of freedom. The code calculates normal, as well as, frictional (tangential) contact forces by means of soft potentials and the aggregate as a whole mimics the effect of non- spherical particles through the implementation of rolling friction. Cohesive forces, and a cohesive stress, are calculated as the net effect of the sum of the van der Waals forces between the smaller regolith, sand and dust (powder) that are present in real asteroids [1]. These finer materials form a matrix of sorts that holds the bigger boulders together. The aggregates were slowly spun up to disruption controlling for angle of friction, cohesion and global shape. Systems with no frictional forces had θ≈ 12° and are in effect granular liquids in the best case scenario. Systems with only surface-surface friction had θ≈ 25°, which is typical in laboratory experiments with spherical glass beads. Systems that also implemented rolling friction had θ≈ 35°, which is typical of non-cohesive granular media on the Earth. How much each aggregate deformed before disruption was directly related to the angle of friction. The greater θ allowed for much less deformation before disruption. Cohesive forces on the other hand controlled the mode of disruption and maximum spin rate and showed that the change from shedding to fission is continuous and therefore, they should not be seen as different disruption processes. The figure shows the deformation and disruption of three initially spherical aggregates (left) and three initially ellipsoidal aggregates (right) with increasing cohesive strength from left to right (θ≈ 35°). Through scaling arguments we could also see these aggregates as having the exact same σ_c=25 Pa but different sizes. If we do that, the aggregates measure about 1.6 km, 5 km, and 22 km, and the particles, or groups of particles being detached now have similar sizes. This has now become a problem of resolution, i.e., the number and size of particles used in a simulation. These results start to raise fundamental questions regarding the difference between shedding and fission. Is it shedding when it is dust grain by dust grain ejection from the main body or when it is in groups of 10, 100, or 100,000 dust particles? Is it fission when a 1-m piece of the asteroid detaches or when it splits in the middle? Which values of θ and σ_c are realistic? These and other questions will be explored. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29884109','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29884109">The Effect of Child Sexual Abuse on Social Functioning in Schizophrenia Spectrum Disorders.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> López-Mongay, Daniel; Ahuir, Maribel; Crosas, Josep Mª; Navarro, J Blas; Monreal, José Antonio; Obiols, Jordi E; Palao, Diego 2018-06-01 The objective of this study was to explore social functioning in schizophrenic patients who have suffered child sexual abuse (CSA) in comparison with those who have not suffered from it in a Spanish sample of 50 patients with schizophrenia or schizoaffective disorder. The Quality of Life (QOL) Scale, the Childhood Trauma Questionnaire (CTQ-SF), and the NEO Five Factor Inventory (NEO-FFI) were administered in this study. We found a CSA prevalence of 22% in our sample. Results showed that QOL global scores reduced by 9.34% at a statistically significant level ( p = .037) in sexually abused patients in comparison with those who did not report experiencing sexual abuse. Regression analysis in the QOL scales showed no differences in intrapsychic foundation scores or in the social relations scale. Scores in the instrumental role scale were reduced by 4.42 points in patients with CSA ( p = .009). Neither neuroticism nor extraversion results differ between the trauma group and those who did not suffer trauma. Clinical implications of these results are discussed. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016IAUS..318..324B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016IAUS..318..324B">From Asteroids to Space Debris</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Benkhaldoun, Zouhair; Moon, Hong-Kyu; Daassou, Ahmed; Park, Jang-Hyun; Lazrek, Mohamed 2016-01-01 Since 2011, Oukaimeden Observatory (OUCA) has become one of the active NEO search facilities in the word. Its discovery statistics shows that the MOSS (Morocco Oukaimeden Sky Survey) project received credits for more than 2,145 new designations, including 3 NEOs and 4 comets. Its excellent astro-climactic characteristics are partly behind the success. The average number of observable nights is around 280 nights per year, while median seeing is 0.8-0.9 arcsec. We completed construction of a new telescope at the site in March 2015. It is Optical Wide-field Patrol (OWL) facility designed and built by Korea Space Science Institute (KASI). The primary objective of this facility is to monitor national space assets of Korea; either wide-field imaging- or fast data acquisition- capabilities enable the 0.5m telescope to conduct observation programs to catalog and follow-up various transient events in the night sky. We present the seeing condition, the OWL system and preliminary results obtained at OWL@Oukaimeden during the past several months. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/5397869-quantitative-bone-scintigraphy-differentiation-necrotizing-external-otitis-from-severe-external-otitis','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/5397869-quantitative-bone-scintigraphy-differentiation-necrotizing-external-otitis-from-severe-external-otitis">Quantitative bone and 67Ga scintigraphy in the differentiation of necrotizing external otitis from severe external otitis</a> <a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a> Uri, N.; Gips, S.; Front, A. 1991-06-01 Qualitative technetium Tc 99m bone scintigraphy using phosphate compounds and gallium 67 scintigraphy were described as a helpful means in diagnosing necrotizing external otitis (NEO). They were, however, claimed to be nonspecific. Quantitative Tc 99m methylene diphosphonate bone scintigraphy and gallium 67 scintigraphy were performed in eight patients with NEO and in 20 patients with severe external otitis, in order to prove usefulness of scintigraphy in the diagnosis of NEO. Ratios of lesion to nonlesion for bone scintigraphy were 1.67 {plus minus} 0.16 in patients with NEO and 1.08 {plus minus} 0.09 in patients with severe external otitis, and formore » gallium 67 scintigraphy they were 1.35 {plus minus} 0.24 in NEO patients and 1.05 {plus minus} 0.03 in patients with severe external otitis. There was no difference in uptake between diabetic patients with severe external otitis and nondiabetic patients. The scintigraphic studies were also evaluated using a qualitative scoring method (scores 0 to +4), according to the intensity of the radiopharmaceutical uptake. This method was found to be inferior in the diagnosis of NEO compared with the quantitative method. We conclude that lesion-to-nonlesion ratios greater than 1.5 and 1.3 on bone and gallium 67 scintigraphy, respectively, are indicative of NEO. Quantitative bone scintigraphy, which is quicker to perform, may be used as a single imaging modality for the diagnosis of NEO.« less </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=271120','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=271120">A neo-sex-chromosome that drives post-zygotic sex determiniation in the Hessian fly</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a> Two nonoverlapping autosomal inversions defined unusual neo-sex chromosomes in the Hessian fly (Mayetiola destructor). Like other neo-sex chromosomes, these were normally heterozygous, present only in one sex, and suppressed recombination around a sex-determining master switch. Their unusual propert... </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4096682','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4096682">Personality Facets and All-Cause Mortality Among Medicare Patients Aged 66 to 102: A Follow-on Study of Weiss and Costa (2005)</a> <a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Costa, Paul T.; Weiss, Alexander; Duberstein, Paul R.; Friedman, Bruce; Siegler, Ilene C. 2014-01-01 Objectives To investigate associations between the personality factors and survival during 8 years follow-up. Methods Domains of personality and selected facet scores were assessed in 597 Medicare recipients (aged 66 to 102 years) who were followed up for approximately 8 years. Personality domains and factors were assessed using the Revised NEO Personality Inventory (NEO-PI-R). Using proportional hazards regression, the present study builds on a previous analysis of the NEO-PI-R domains and selected facet scores, which revealed that the Neuroticism facet Impulsiveness, Agreeableness facet Straightforwardness, and Conscientiousness facet Self-Discipline were related to longer life during 4 years of follow-up. In the present study, we extended the follow-up period by an additional 4 years, examining all 30 facets, and using accelerated failure time (AFT) modeling as an additional analytic approach. Unlike proportional hazards regression, AFT permits inferences about the median survival length conferred by predictors. Each facet was tested in a model that included health-related covariates and NEO-PI-R factor scores for dimensions that did not include that facet. Results Over the 8-year mortality surveillance period, Impulsiveness was not significant, but Straightforwardness and Self-Discipline remained significant predictors of longevity. When dichotomized, being high versus average or low on Self-Discipline was associated with an approximately 34% increase in median lifespan. Longer mortality surveillance also revealed that each standard deviation of Altruism, Compliance, Tender-Mindedness, and Openness to Fantasy was associated with an estimated 9–11% increase in median survival time. Conclusions After extending the follow-up period from 4 to 8 years, Self-Discipline remained a powerful predictor of survival. Facets associated with imagination, generosity, and higher quality interpersonal interactions become increasingly important when the follow-up period was extended to 8 years. PMID:24933014 </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013CSEd...23...24G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013CSEd...23...24G">Mastering cognitive development theory in computer science education</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Gluga, Richard; Kay, Judy; Lister, Raymond; Simon; Kleitman, Sabina 2013-03-01 To design an effective computer science curriculum, educators require a systematic method of classifying the difficulty level of learning activities and assessment tasks. This is important for curriculum design and implementation and for communication between educators. Different educators must be able to use the method consistently, so that classified activities and assessments are comparable across the subjects of a degree, and, ideally, comparable across institutions. One widespread approach to supporting this is to write learning objects in terms of Bloom's Taxonomy. This, or other such classifications, is likely to be more effective if educators can use them consistently, in the way experts would use them. To this end, we present the design and evaluation of our online interactive web-based tutorial system, which can be configured and used to offer training in different classification schemes. We report on results from three evaluations. First, 17 computer science educators complete a tutorial on using Bloom's Taxonomy to classify programming examination questions. Second, 20 computer science educators complete a Neo-Piagetian tutorial. Third evaluation was a comparison of inter-rater reliability scores of computer science educators classifying programming questions using Bloom's Taxonomy, before and after taking our tutorial. Based on the results from these evaluations, we discuss the effectiveness of our tutorial system design for teaching computer science educators how to systematically and consistently classify programming examination questions. We also discuss the suitability of Bloom's Taxonomy and Neo-Piagetian theory for achieving this goal. The Bloom's and Neo-Piagetian tutorials are made available as a community resource. The contributions of this paper are the following: the tutorial system for learning classification schemes for the purpose of coding the difficulty of computing learning materials; its evaluation; new insights into the consistency that computing educators can achieve using Bloom; and first insights into the use of Neo-Piagetian theory by a group of classifiers. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=economy&pg=7&id=EJ1134316','ERIC'); return false;" href="https://eric.ed.gov/?q=economy&pg=7&id=EJ1134316">Neo-Nationalism in Higher Education: Case of South Africa</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Lee, Jenny J. 2017-01-01 Given the rise of regional hubs, emerging economies are experiencing international student growth as higher education providers in their respective regions. This study examined the neo-national experiences of international students in South Africa. Neo-nationalism refers to a new nationalism based national order in the new global economy. The… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=neoliberalism+AND+education&id=EJ927200','ERIC'); return false;" href="https://eric.ed.gov/?q=neoliberalism+AND+education&id=EJ927200">Neo-Liberalism in Crisis? Educational Dimensions</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Small, David 2011-01-01 Until the global financial crisis, neo-liberalism had appeared invincible. This article examines the global rise of neo-liberalism and its impact on education, particularly its treatment of the social democratic ideal of equality. Drawing on examples from education and other socio-political factors, it considers whether the financial crisis is… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=income+AND+inequality+AND+economic+AND+growth&pg=3&id=EJ818091','ERIC'); return false;" href="https://eric.ed.gov/?q=income+AND+inequality+AND+economic+AND+growth&pg=3&id=EJ818091">Population Policies and Education: Exploring the Contradictions of Neo-Liberal Globalisation</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Bovill, Catherine; Leppard, Margaret 2006-01-01 The world is increasingly characterised by profound income, health and social inequalities (Appadurai, 2000). In recent decades development initiatives aimed at reducing these inequalities have been situated in a context of increasing globalisation with a dominant neo-liberal economic orthodoxy. This paper argues that neo-liberal globalisation… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA415145','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA415145">An Emerging Security Community in the Americas?: A Theoretical Analysis of the Consequences of the Post-Cold War Inter-American Democracy Regime</a> <a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a> 2003-03-01 1. The Kantian Perspective on Peace .....................................................7 2. A Neo- Kantian Perspective on Peace...10 a. The Empirical Evidence for a “Neo- Kantian Peace”............11 b. Potential Consequences of a Neo- Kantian Peace... </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=modern+AND+education+AND+traditional+AND+education&pg=3&id=EJ1040420','ERIC'); return false;" href="https://eric.ed.gov/?q=modern+AND+education+AND+traditional+AND+education&pg=3&id=EJ1040420">Educational Modes of Thinking in Neo-Confucianism: A Traditional Lens for Rethinking Modern Education</a> <a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a> Hwang, Keumjoong 2013-01-01 This article discusses the distinctive educational modes of thinking in Neo-Confucianism, with an interest of extracting Confucian reflective views for modern education of traditionally Confucian East Asia. Neo-Confucian typical modes of thinking on education are characterized as "heart-mind centered" and "learning as… </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA482519','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA482519">Role of CDK4 in Breast Development and Cancer</a> <a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a> 2008-04-01 Steward, A. H. Parr, M. D. Thomas, J. A. Henry, B. Angus , T. W. Lennard, C. H. Horne, Oncogene 11, 885 (1995). 12. J. Bartkova, J. Likas, M. Strauss...Cdk6 and Cdk2 in all four of the genotypes studied here. The results presented in Fig. 4A show that in both Cdk4(neo/neo):MMTV-wnt and in Cdk4(neo/neo...contrast, the levels of Cdk6 and Cdk2 were approximately equal in all four genotypes . These results suggest that neither Cdk6 nor Cdk2 compensate for </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25580613','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25580613">Distinguishing between demoralization and specific personality traits in clinical assessment with the NEO-PI-R.</a> <a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a> Noordhof, Arjen; Sellbom, Martin; Eigenhuis, Annemarie; Kamphuis, Jan H 2015-06-01 Demoralization, a nonspecific unpleasant state that is common in clinical practice, has been identified as a potential source of nonspecificity in the assessment of personality and psychopathology. The aim of this research was to distinguish between Demoralization and specific personality traits in a widely used measure of personality: the Neuroticism-Extraversion-Openness Personality Inventory-Revised (NEO-PI-R). NEO-PI-R and Minnesota Multiphasic Personality Inventory-2 questionnaires were completed by 278 patients of a specialized clinic for personality disorders in The Netherlands. Furthermore, a replication sample was used consisting of 405 patients from the same institution who completed NEO-PI-R questionnaires, as well. A measure of Demoralization was derived (NEOdem, a NEO-PI-R-based Demoralization scale) using factor analytic techniques. Results indicated that the Demoralization Scale scores were reliable and showed expected patterns of convergence and divergence with conceptually relevant Minnesota Multiphasic Personality Inventory-2-RF scales. When items contributing to Demoralization-related variance were removed from the NEO-PI-R scales, increased specificity was notable with regard to external correlates. These results provide supportive evidence for the validity and heuristic potential of distinguishing between Demoralization and specific personality traits within the NEO-PI-R. (c) 2015 APA, all rights reserved). </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4268413','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4268413">Neonatal amygdala lesions advance pubertal timing in female rhesus macaques</a> <a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a> Stephens, Shannon B.Z.; Raper, Jessica; Bachevalier, Jocelyne; Wallen, Kim 2014-01-01 Summary Social context influences the timing of puberty in both humans and nonhuman primates, such as delayed first ovulation in low-ranking rhesus macaques, but the brain region(s) mediating the effects of social context on pubertal timing are unknown. The amygdala is important for responding to social information and thus, is a potential brain region mediating the effects of social context on pubertal timing. In this study, female rhesus macaques living in large, species-typical, social groups received bilateral neurotoxic amygdala lesions at one month of age and pubertal timing was examined beginning at 14 months of age. Pubertal timing was affected in neonatal amygdala-lesioned females (Neo-A), such that they experienced significantly earlier menarche and first ovulation than did control females (Neo-C). Duration between menarche and first ovulation did not differ between Neo-A and Neo-C females, indicating earlier first ovulation in Neo-A females was likely a consequence of earlier menarche. Social rank of Neo-A females was related to age at menarche, but not first ovulation, and social rank was not related to either event in Neo-C females. It is more likely that amygdalectomy affects pubertal timing through its modulation of GABA-ergic mechanisms rather than as a result of the removal of a social-contextual inhibition on pubertal timing. PMID:25462903 </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016amos.confE..80G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016amos.confE..80G">Real-Time Atmospheric Phase Fluctuation Correction Using a Phased Array of Widely Separated Antennas: X-Band Results and Ka-Band Progress</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Geldzahler, B.; Birr, R.; Brown, R.; Grant, K.; Hoblitzell, R.; Miller, M.; Woods, G.; Argueta, A.; Ciminera, M.; Cornish, T.; D'Addario, L.; Davarian, F.; Kocz, J.; Lee, D.; Morabito, D.; Tsao, P.; Jakeman-Flores, H.; Ott, M.; Soloff, J.; Denn, G.; Church, K.; Deffenbaugh, P. 2016-09-01 NASA is pursuing a demonstration of coherent uplink arraying at 7.145-7.190 GHz (X-band) and 30-31 GHz (Kaband) using three 12m diameter COTS antennas separated by 60m at the Kennedy Space Center in Florida. In addition, we have used up to three 34m antennas separated by 250m at the Goldstone Deep Space Communication Complex in California at X-band 7.1 GHz incorporating real-time correction for tropospheric phase fluctuations. Such a demonstration can enable NASA to design and establish a high power, high resolution, 24/7 availability radar system for (a) tracking and characterizing observations of Near Earth Objects (NEOs), (b) tracking, characterizing and determining the statistics of small-scale (≤10cm) orbital debris, (c) incorporating the capability into its space communication and navigation tracking stations for emergency spacecraft commanding in the Ka band era which NASA is entering, and (d) fielding capabilities of interest to other US government agencies. We present herein the results of our phased array uplink combining at near 7.17 and 8.3 GHz using widely separated antennas demonstrations at both locales, the results of a study to upgrade from a communication to a radar system, and our vision for going forward in implementing a high performance, low lifecycle cost multi-element radar array. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.T33E2976W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.T33E2976W">Mantle Convection on Modern Supercomputers</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Weismüller, J.; Gmeiner, B.; Huber, M.; John, L.; Mohr, M.; Rüde, U.; Wohlmuth, B.; Bunge, H. P. 2015-12-01 Mantle convection is the cause for plate tectonics, the formation of mountains and oceans, and the main driving mechanism behind earthquakes. The convection process is modeled by a system of partial differential equations describing the conservation of mass, momentum and energy. Characteristic to mantle flow is the vast disparity of length scales from global to microscopic, turning mantle convection simulations into a challenging application for high-performance computing. As system size and technical complexity of the simulations continue to increase, design and implementation of simulation models for next generation large-scale architectures is handled successfully only in an interdisciplinary context. A new priority program - named SPPEXA - by the German Research Foundation (DFG) addresses this issue, and brings together computer scientists, mathematicians and application scientists around grand challenges in HPC. Here we report from the TERRA-NEO project, which is part of the high visibility SPPEXA program, and a joint effort of four research groups. TERRA-NEO develops algorithms for future HPC infrastructures, focusing on high computational efficiency and resilience in next generation mantle convection models. We present software that can resolve the Earth's mantle with up to 1012 grid points and scales efficiently to massively parallel hardware with more than 50,000 processors. We use our simulations to explore the dynamic regime of mantle convection and assess the impact of small scale processes on global mantle flow. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110008769','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110008769">HDU Deep Space Habitat (DSH) Overview</a> <a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a> Kennedy, Kriss J. 2011-01-01 This paper gives an overview of the National Aeronautics and Space Administration (NASA) led multi-center Habitat Demonstration Unit (HDU) project Deep Space Habitat (DSH) analog that will be field-tested during the 2011 Desert Research and Technologies Studies (D-RATS) field tests. The HDU project is a technology pull project that integrates technologies and innovations from multiple NASA centers. This project will repurpose the HDU Pressurized Excursion Module (PEM) that was field tested in the 2010 D-RATS, adding habitation functionality to the prototype unit. The 2010 configuration of the HDU-PEM consisted of a lunar surface laboratory module that was used to bring over 20 habitation-related technologies together in a single platform that could be tested as an advanced habitation analog in the context of mission architectures and surface operations. The 2011 HDU-DSH configuration will build upon the PEM work, and emphasize validity of crew operations (habitation and living, etc), EVA operations, mission operations, logistics operations, and science operations that might be required in a deep space context for Near Earth Object (NEO) exploration mission architectures. The HDU project consists of a multi-center team brought together in a skunkworks approach to quickly build and validate hardware in analog environments. The HDU project is part of the strategic plan from the Exploration Systems Mission Directorate (ESMD) Directorate Integration Office (DIO) and the Exploration Mission Systems Office (EMSO) to test destination elements in analog environments. The 2011 analog field test will include Multi Mission Space Exploration Vehicles (MMSEV) and the DSH among other demonstration elements to be brought together in a mission architecture context. This paper will describe overall objectives, various habitat configurations, strategic plan, and technology integration as it pertains to the 2011 field tests. </li> <li> <a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Icar..245...87B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Icar..245...87B">The mass disruption of Jupiter Family comets</a> <a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a> Belton, Michael J. S. 2015-01-01 I show that the size-distribution of small scattered-disk trans-neptunian objects when derived from the observed size-distribution of Jupiter Family comets (JFCs) and other observational constraints implies that a large percentage (94-97%) of newly arrived active comets within a range of 0.2-15.4 km effective radius must physically disrupt, i.e., macroscopically disintegrate, within their median dynamical lifetime. Additional observational constraints include the numbers of dormant and active nuclei in the near-Earth object (NEO) population and the slope of their size distributions. I show that the cumulative power-law slope (-2.86 to -3.15) of the scattered-disk TNO hot population between 0.2 and 15.4 km effective radius is only weakly dependent on the size-dependence of the otherwise unknown disruption mechanism. Evidently, as JFC nuclei from the scattered disk evolve into the inner Solar System only a fraction achieve dormancy while the vast majority of small nuclei (e.g., primarily those with effective radius <2 km) break-up. The percentage disruption rate appears to be comparable with that of the dynamically distinct Oort cloud and Halley type comets (Levison, H.F., Morbidelli, A., Dones, L., Jedicke, R., Wiegert, P.A., Bottke Jr., W.F. [2002]. Science 296, 2212-2215) suggesting that all types of comet nuclei may have similar structural characteristics even though they may have different source regions and thermal histories. The typical disruption rate for a 1 km radius active nucleus is ∼5 × 10-5 disruptions/year and the dormancy rate is typically 3 times less. We also estimate that average fragmentation rates range from 0.01 to 0.04 events/year/comet, somewhat above the lower limit of 0.01 events/year/comet observed by Chen and Jewitt (Chen, J., Jewitt, D.C. [1994]. Icarus 108, 265-271). </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active">25</li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> </div> <div class="footer-extlink text-muted" style="margin-bottom:1rem; text-align:center;">Some links on this page may take you to non-federal websites. 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