Sample records for asteroid terminal defense

  1. Capturing asteroids into bound orbits around the earth: Massive early return on an asteroid terminal defense system

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

    Hills, J.G.

    1992-02-06

    Nuclear explosives may be used to capture small asteroids (e.g., 20--50 meters in diameter) into bound orbits around the earth. The captured objects could be used for construction material for manned and unmanned activity in Earth orbit. Asteroids with small approach velocities, which are the ones most likely to have close approaches to the Earth, require the least energy for capture. They are particularly easy to capture if they pass within one Earth radius of the surface of the Earth. They could be intercepted with intercontinental missiles if the latter were retrofit with a more flexible guiding and homing capability.more » This asteroid capture-defense system could be implemented in a few years at low cost by using decommissioned ICMs. The economic value of even one captured asteroid is many times the initial investment. The asteroid capture system would be an essential part of the learning curve for dealing with larger asteroids that can hit the earth.« less

  2. New Hypervelocity Terminal Intercept Guidance Systems for Deflecting/Disrupting Hazardous Asteroids

    NASA Astrophysics Data System (ADS)

    Lyzhoft, Joshua Richard

    Computational modeling and simulations of visual and infrared (IR) sensors are investigated for a new hypervelocity terminal guidance system of intercepting small asteroids (50 to 150 meters in diameter). Computational software tools for signal-to-noise ratio estimation of visual and IR sensors, estimation of minimum and maximum ranges of target detection, and GPU (Graphics Processing Units)-accelerated simulations of the IR-based terminal intercept guidance systems are developed. Scaled polyhedron models of known objects, such as the Rosetta mission's Comet 67P/C-G, NASA's OSIRIS-REx Bennu, and asteroid 433 Eros, are utilized in developing a GPU-based simulation tool for the IR-based terminal intercept guidance systems. A parallelized-ray tracing algorithm for simulating realistic surface-to-surface shadowing of irregular-shaped asteroids or comets is developed. Polyhedron solid-angle approximation is also considered. Using these computational models, digital image processing is investigated to determine single or multiple impact locations to assess the technical feasibility of new planetary defense mission concepts of utilizing a Hypervelocity Asteroid Intercept Vehicle (HAIV) or a Multiple Kinetic-energy Interceptor Vehicle (MKIV). Study results indicate that the IR-based guidance system outperforms the visual-based system in asteroid detection and tracking. When using an IR sensor, predicting impact locations from filtered images resulted in less jittery spacecraft control accelerations than conducting missions with a visual sensor. Infrared sensors have also the possibility to detect asteroids at greater distances, and if properly used, can aid in terminal phase guidance for proper impact location determination for the MKIV system. Emerging new topics of the Minimum Orbit Intersection Distance (MOID) estimation and the Full-Two-Body Problem (F2BP) formulation are also investigated to assess a potential near-Earth object collision risk and the proximity gravity effects of an irregular-shaped binary-asteroid target on a standoff nuclear explosion mission.

  3. Proximity Operations for the Robotic Boulder Capture Option for the Asteroid Redirect Mission

    NASA Technical Reports Server (NTRS)

    Reeves, David M.; Naasz, Bo J.; Wright, Cinnamon A.; Pini, Alex J.

    2014-01-01

    In September of 2013, the Asteroid Robotic Redirect Mission (ARRM) Option B team was formed to expand on NASA's previous work on the robotic boulder capture option. While the original Option A concept focuses on capturing an entire smaller Near-Earth Asteroid (NEA) using an inflatable bag capture mechanism, this design seeks to land on a larger NEA and retrieve a boulder off of its surface. The Option B team has developed a detailed and feasible mission concept that preserves many aspects of Option A's vehicle design while employing a fundamentally different technique for returning a significant quantity of asteroidal material to the Earth-Moon system. As part of this effort, a point of departure proximity operations concept was developed complete with a detailed timeline, as well as DeltaV and propellant allocations. Special attention was paid to the development of the approach strategy, terminal descent to the surface, controlled ascent with the captured boulder, and control during the Enhanced Gravity Tractor planetary defense demonstration. The concept of retrieving a boulder from the surface of an asteroid and demonstrating the Enhanced Gravity Tractor planetary defense technique is found to be feasible and within the proposed capabilities of the Asteroid Redirect Vehicle (ARV). While this point of departure concept initially focuses on a mission to Itokawa, the proximity operations design is also shown to be extensible to wide range of asteroids.

  4. Near-Earth object intercept trajectory design for planetary defense

    NASA Astrophysics Data System (ADS)

    Vardaxis, George; Wie, Bong

    2014-08-01

    Tracking the orbit of asteroids and planning for asteroid missions have ceased to be a simple exercise, and become more of a necessity, as the number of identified potentially hazardous near-Earth asteroids increases. Several software tools such as Mystic, MALTO, Copernicus, SNAP, OTIS, and GMAT have been developed by NASA for spacecraft trajectory optimization and mission design. However, this paper further expands upon the development and validation of an Asteroid Mission Design Software Tool (AMiDST), through the use of approach and post-encounter orbital variations and analytic keyhole theory. Combining these new capabilities with that of a high-precision orbit propagator, this paper describes fictional mission trajectory design examples of using AMiDST as applied to a fictitious asteroid 2013 PDC-E. During the 2013 IAA Planetary Defense Conference, the asteroid 2013 PDC-E was used for an exercise where participants simulated the decision-making process for developing deflection and civil defense responses to a hypothetical asteroid threat.

  5. DE-STARLITE: A directed energy planetary defense mission

    NASA Astrophysics Data System (ADS)

    Kosmo, Kelly; Pryor, Mark; Lubin, Philip; Hughes, Gary B.; O'Neill, Hugh; Meinhold, Peter; Suen, Jonathan; Riley, Jordan; Griswold, Janelle; Cook, Brianna V.; Johansson, Isabella E.; Zhang, Qicheng; Walsh, Kevin; Melis, Carl; Kangas, Miikka; Bible, Johanna; Motta, Caio; Brashears, Travis; Mathew, Shana; Bollag, Justin

    2014-09-01

    This paper presents the motivation behind and design of a directed energy planetary defense system that utilizes laser ablation of an asteroid to impart a deflecting force on the target. The proposed system is called DE-STARLITE for Directed Energy System for Targeting of Asteroids and ExploRation - LITE as it is a small, stand-on unit of a larger standoff DE-STAR system. Pursuant to the stand-on design, ion engines will propel the spacecraft from low-Earth orbit (LEO) to the near-Earth asteroid (NEA). During laser ablation, the asteroid itself becomes the "propellant"; thus a very modest spacecraft can deflect an asteroid much larger than would be possible with a system of similar mission mass using ion beam deflection (IBD) or a gravity tractor. DE-STARLITE is capable of deflecting an Apophis-class (325 m diameter) asteroid with a 15-year targeting time. The mission fits within the rough mission parameters of the Asteroid Redirect Mission (ARM) program in terms of mass and size and has much greater capability for planetary defense than current proposals and is readily scalable to the threat. It can deflect all known threats with sufficient warning.

  6. Impact risk assessment and planetary defense mission planning for asteroid 2015 PDC

    NASA Astrophysics Data System (ADS)

    Vardaxis, George; Sherman, Peter; Wie, Bong

    2016-05-01

    In this paper, an integrated utilization of analytic keyhole theory, B-plane mapping, and planetary encounter geometry, augmented by direct numerical simulation, is shown to be useful in determining the impact risk of an asteroid with the Earth on a given encounter, as well on potential future encounters via keyhole passages. The accurate estimation of the impact probability of hazardous asteroids is extremely important for planetary defense mission planning. Asteroids in Earth resonant orbits are particularly troublesome because of the continuous threat they pose in the future. Based on the trajectories of the asteroid and the Earth, feasible mission trajectories can be found to mitigate the impact threat of hazardous asteroids. In order to try to ensure mission success, trajectories are judged based on initial and final mission design parameters that would make the mission easier to complete. Given the potential of a short-warning time scenario, a disruption mission considered in this paper occurs approximately one year prior to the anticipated impact date. Expanding upon the established theory, a computational method is developed to estimate the impact probability of the hazardous asteroid, in order to assess the likelihood of an event, and then investigate the fragmentation of the asteroid due to a disruption mission and analyze its effects on the current and future encounters of the fragments with Earth. A fictional asteroid, designated as 2015 PDC - created as an example asteroid risk exercise for the 2015 Planetary Defence Conference, is used as a reference target asteroid to demonstrate the effectiveness and applicability of computational tools being developed for impact risk assessment and planetary defense mission planning for a hazardous asteroid or comet.

  7. Asteroid Redirect Mission Proximity Operations for Reference Target Asteroid 2008 EV5

    NASA Technical Reports Server (NTRS)

    Reeves, David M.; Mazanek, Daniel D.; Cichy, Benjamin D.; Broschart, Steve B.; Deweese, Keith D.

    2016-01-01

    NASA's Asteroid Redirect Mission (ARM) is composed of two segments, the Asteroid Redirect Robotic Mission (ARRM), and the Asteroid Redirect Crewed Mission (ARCM). In March of 2015, NASA selected the Robotic Boulder Capture Option1 as the baseline for the ARRM. This option will capture a multi-ton boulder, (typically 2-4 meters in size) from the surface of a large (greater than approx.100 m diameter) Near-Earth Asteroid (NEA) and return it to cis-lunar space for subsequent human exploration during the ARCM. Further human and robotic missions to the asteroidal material would also be facilitated by its return to cis-lunar space. In addition, prior to departing the asteroid, the Asteroid Redirect Vehicle (ARV) will perform a demonstration of the Enhanced Gravity Tractor (EGT) planetary defense technique2. This paper will discuss the proximity operations which have been broken into three phases: Approach and Characterization, Boulder Capture, and Planetary Defense Demonstration. Each of these phases has been analyzed for the ARRM reference target, 2008 EV5, and a detailed baseline operations concept has been developed.

  8. Asteroid Studies: A 35-Year Forecast

    NASA Astrophysics Data System (ADS)

    Rivkin, A. S.; Denevi, B. W.; Klima, R. L.; Ernst, C. M.; Chabot, N. L.; Barnouin, O. S.; Cohen, B. A.

    2017-02-01

    We are in an active time for asteroid studies, which fall at the intersection of science, planetary defense, human exploration, and in situ resource utilization. We look forward and extrapolate what the future may hold for asteroid science.

  9. BILLIARDS: A Demonstration Mission for Hundred-Meter Class Near Earth Asteroid Disruption

    NASA Technical Reports Server (NTRS)

    Marcus, Matthew; Sloane, Joshua; Ortiz, Oliver; Barbee, Brent W.

    2015-01-01

    Currently, no planetary defense demonstration mission has ever been flown. While Nuclear Explosive Devices (NEDs) have significantly more energy than a kinetic impactor launched directly from Earth, they present safety and political complications, and therefore may only be used when absolutely necessary. The Baseline Instrumented Lithology Lander, Inspector, and Asteroid Redirection Demonstration System (BILLIARDS) is a demonstration mission for planetary defense, which is capable of delivering comparable energy to the lower range of NED capabilities in the form of a safer kinetic impactor. A small asteroid (<10m) is captured by a spacecraft, which greatly increases the mass available as a kinetic impactor, without the need to bring all of the mass out of Earth's gravity well. The small asteroid is then deflected onto a collision course with a larger (approx. 100m) asteroid. This collision will deflect or disrupt the larger asteroid. To reduce the cost and complexity, an asteroid pair which has a natural close approach is selected.

  10. Asteroid-Generated Tsunami and Impact Risk

    NASA Astrophysics Data System (ADS)

    Boslough, M.; Aftosmis, M.; Berger, M. J.; Ezzedine, S. M.; Gisler, G.; Jennings, B.; LeVeque, R. J.; Mathias, D.; McCoy, C.; Robertson, D.; Titov, V. V.; Wheeler, L.

    2016-12-01

    The justification for planetary defense comes from a cost/benefit analysis, which includes risk assessment. The contribution from ocean impacts and airbursts is difficult to quantify and represents a significant uncertainty in our assessment of the overall risk. Our group is currently working toward improved understanding of impact scenarios that can generate dangerous tsunami. The importance of asteroid-generated tsunami research has increased because a new Science Definition Team, at the behest of NASA's Planetary Defense Coordinating Office, is now updating the results of a 2003 study on which our current planetary defense policy is based Our group was formed to address this question on many fronts, including asteroid entry modeling, tsunami generation and propagation simulations, modeling of coastal run-ups, inundation, and consequences, infrastructure damage estimates, and physics-based probabilistic impact risk assessment. We also organized the Second International Workshop on Asteroid Threat Assessment, focused on asteroid-generated tsunami and associated risk (Aug. 23-24, 2016). We will summarize our progress and present the highlights of our workshop, emphasizing its relevance to earth and planetary science. 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.

  11. Directed energy missions for planetary defense

    NASA Astrophysics Data System (ADS)

    Lubin, Philip; Hughes, Gary B.; Eskenazi, Mike; Kosmo, Kelly; Johansson, Isabella E.; Griswold, Janelle; Pryor, Mark; O'Neill, Hugh; Meinhold, Peter; Suen, Jonathan; Riley, Jordan; Zhang, Qicheng; Walsh, Kevin; Melis, Carl; Kangas, Miikka; Motta, Caio; Brashears, Travis

    2016-09-01

    Directed energy for planetary defense is now a viable option and is superior in many ways to other proposed technologies, being able to defend the Earth against all known threats. This paper presents basic ideas behind a directed energy planetary defense system that utilizes laser ablation of an asteroid to impart a deflecting force on the target. A conceptual philosophy called DE-STAR, which stands for Directed Energy System for Targeting of Asteroids and exploration, is an orbiting stand-off system, which has been described in other papers. This paper describes a smaller, stand-on system known as DE-STARLITE as a reduced-scale version of DE-STAR. Both share the same basic heritage of a directed energy array that heats the surface of the target to the point of high surface vapor pressure that causes significant mass ejection thus forming an ejection plume of material from the target that acts as a rocket to deflect the object. This is generally classified as laser ablation. DE-STARLITE uses conventional propellant for launch to LEO and then ion engines to propel the spacecraft from LEO to the near-Earth asteroid (NEA). During laser ablation, the asteroid itself provides the propellant source material; thus a very modest spacecraft can deflect an asteroid much larger than would be possible with a system of similar mission mass using ion beam deflection (IBD) or a gravity tractor. DE-STARLITE is capable of deflecting an Apophis-class (325 m diameter) asteroid with a 1- to 15-year targeting time (laser on time) depending on the system design. The mission fits within the rough mission parameters of the Asteroid Redirect Mission (ARM) program in terms of mass and size. DE-STARLITE also has much greater capability for planetary defense than current proposals and is readily scalable to match the threat. It can deflect all known threats with sufficient warning.

  12. Compositional studies of primitive asteroids

    NASA Technical Reports Server (NTRS)

    Vilas, Faith

    1991-01-01

    Primitive asteroids in the solar system (C, P, D class and associated subclasses) are believed to have undergone less thermal processing compared with the differential (S class) asteroids. Telescopic spectra of C class asteroids show effects of aqueous alteration products produced when heating of the asteroids was sufficient to melt surface water, but not strong enough to produce differentiation. Spectrum analysis of P and D class asteroids suggests that aqueous alteration terminated in the outer belt and did not operate at the distance of Jupiter's orbit.

  13. Planetary Defense From Space: Part 2 (Simple) Asteroid Deflection Law

    NASA Astrophysics Data System (ADS)

    Maccone, Claudio

    2006-06-01

    A system of two space bases housing missiles for an efficient Planetary Defense of the Earth from asteroids and comets was firstly proposed by this author in 2002. It was then shown that the five Lagrangian points of the Earth Moon system lead naturally to only two unmistakable locations of these two space bases within the sphere of influence of the Earth. These locations are the two Lagrangian points L1 (in between the Earth and the Moon) and L3 (in the direction opposite to the Moon from the Earth). In fact, placing missiles based at L1 and L3 would enable the missiles to deflect the trajectory of incoming asteroids by hitting them orthogonally to their impact trajectory toward the Earth, thus maximizing the deflection at best. It was also shown that confocal conics are the only class of missile trajectories fulfilling this “best orthogonal deflection” requirement. The mathematical theory developed by the author in the years 2002 2004 was just the beginning of a more expanded research program about the Planetary Defense. In fact, while those papers developed the formal Keplerian theory of the Optimal Planetary Defense achievable from the Earth Moon Lagrangian points L1 and L3, this paper is devoted to the proof of a simple “(small) asteroid deflection law” relating directly the following variables to each other:the speed of the arriving asteroid with respect to the Earth (known from the astrometric observations);the asteroid's size and density (also supposed to be known from astronomical observations of various types);the “security radius” of the Earth, that is, the minimal sphere around the Earth outside which we must force the asteroid to fly if we want to be safe on Earth. Typically, we assume the security radius to equal about 10,000 km from the Earth center, but this number might be changed by more refined analyses, especially in the case of “rubble pile” asteroids;the distance from the Earth of the two Lagrangian points L1 and L3 where the defense missiles are to be housed;the deflecting missile's data, namely its mass and especially its “extra-boost”, that is, the extra-energy by which the missile must hit the asteroid to achieve the requested minimal deflection outside the security radius around the Earth.This discovery of the simple “asteroid deflection law” presented in this paper was possible because:In the vicinity of the Earth, the hyperbola of the arriving asteroid is nearly the same as its own asymptote, namely, the asteroid's hyperbola is very much like a straight line. We call this approximation the line/circle approximation. Although “rough” compared to the ordinary Keplerian theory, this approximation simplifies the mathematical problem to such an extent that two simple, final equations can be derived.The confocal missile trajectory, orthogonal to this straight line, ceases then to be an ellipse to become just a circle centered at the Earth. This fact also simplifies things greatly. Our results are thus to be regarded as a good engineering approximation, valid for a preliminary astronautical design of the missiles and bases at L1 and L3.Still, many more sophisticated refinements would be needed for a complete Planetary Defense System:taking into account many perturbation forces of all kinds acting on both the asteroids and missiles shot from L1 and L3;adding more (non-optimal) trajectories of missiles shot from either the Lagrangian points L4 and L5 of the Earth Moon system or from the surface of the Moon itself;encompassing the full range of missiles currently available to the USA (and possibly other countries) so as to really see “which missiles could divert which asteroids”, even just within the very simplified scheme proposed in this paper.In summary: outlined for the first time in February 2002, our Confocal Planetary Defense concept is a simplified Keplerian Theory that already proved simple enough to catch the attention of scholars, popular writers, and representatives of the US Military. These developments would hopefully mark the beginning of a general mathematical vision for building an efficient Planetary Defense System in space and in the vicinity of the Earth, although not on the surface of the Earth itself! We must make a real progress beyond academic papers, Hollywood movies and secret military plans, before asteroids like 99942 Apophis get close enough to destroy us in 2029 or a little later.

  14. Mission Design and Optimal Asteroid Deflection for Planetary Defense

    NASA Technical Reports Server (NTRS)

    Sarli, Bruno V.; Knittel, Jeremy M.; Englander, Jacob A.; Barbee, Brent W.

    2017-01-01

    Planetary defense is a topic of increasing interest for many reasons, which has been mentioned in "Vision and Voyages for Planetary Science in the Decade 2013-2022''. However, perhaps one of the most significant rationales for asteroid studies is the number of close approaches that have been documented recently. A space mission with a planetary defense objective aims to deflect the threatening body as far as possible from Earth. The design of a mission that optimally deflects an asteroid has different challenges: speed, precision, and system trade-off. This work addresses such issues and develops a fast transcription of the problem that can be implemented into an optimization tool, which allows for a broader trade study of different mission concepts with a medium fidelity. Such work is suitable for a mission?s preliminary study. It is shown, using the fictitious asteroid impact scenario 2017 PDC, that the complete tool is able to account for the orbit sensitivity to small perturbations and quickly optimize a deflection trajectory. The speed in which the tool operates allows for a trade study between the available hardware. As a result, key deflection dates and mission strategies are identified for the 2017 PDC.

  15. Mission Design and Optimal Asteroid Deflection for Planetary Defense

    NASA Technical Reports Server (NTRS)

    Sarli, Bruno V.; Knittel, Jeremy M.; Englander, Jacob A.; Barbee, Brent W.

    2017-01-01

    Planetary defense is a topic of increasing interest for many reasons, which has been mentioned in "Vision and Voyages for Planetary Science in the Decade 2013-2022". However, perhaps one of the most significant rationales for asteroid studies is the number of close approaches that have been documented recently. A space mission with a planetary defense objective aims to deflect the threatening body as far as possible from Earth. The design of a mission that optimally deflects an asteroid has different challenges: speed, precision, and system trade-off. This work addresses such issues and develops a fast transcription of the problem that can be implemented into an optimization tool, which allows for a broader trade study of different mission concepts with a medium fidelity. Such work is suitable for a mission's preliminary study. It is shown, using the fictitious asteroid impact scenario 2017 PDC, that the complete tool is able to account for the orbit sensitivity to small perturbations and quickly optimize a deflection trajectory. The speed in which the tool operates allows for a trade study between the available hardware. As a result, key deflection dates and mission strategies are identified for the 2017 PDC.

  16. Estimating the Mass of Asteroid 433 Eros During the Near Spacecraft Flyby

    NASA Technical Reports Server (NTRS)

    Yeomans, D.; Antreasian, P.; Cheng, A.; Dunham, D.; Farquhar, R.; Gaskell, R.; Giorgini, J.; Helfrich, C.; Konopliv, A.; McAdams, J.; hide

    1999-01-01

    The terminal navigation of the Near-Earth Asteroid Rendezvous (NEAR) spacecraft during its flyby of asteroid 433 Eros on December 23, 1998 involved coordinated efforts to determine the heliocentric orbits of the spacecraft and Eros and then to determine the relative trajectory of the spacecraft with respect ot Eros.

  17. Robotic Missions to Small Bodies and Their Potential Contributions to Human Exploration and Planetary Defense

    NASA Technical Reports Server (NTRS)

    Abell, Paul A.; Rivkin, Andrew S.

    2015-01-01

    Introduction: Robotic missions to small bodies will directly address aspects of NASA's Asteroid Initiative and will contribute to future human exploration and planetary defense. The NASA Asteroid Initiative is comprised of two major components: the Grand Challenge and the Asteroid Mission. The first component, the Grand Challenge, focuses on protecting Earth's population from asteroid impacts by detecting potentially hazardous objects with enough warning time to either prevent them from impacting the planet, or to implement civil defense procedures. The Asteroid Mission involves sending astronauts to study and sample a near-Earth asteroid (NEA) prior to conducting exploration missions of the Martian system, which includes Phobos and Deimos. The science and technical data obtained from robotic precursor missions that investigate the surface and interior physical characteristics of an object will help identify the pertinent physical properties that will maximize operational efficiency and reduce mission risk for both robotic assets and crew operating in close proximity to, or at the surface of, a small body. These data will help fill crucial strategic knowledge gaps (SKGs) concerning asteroid physical characteristics that are relevant for human exploration considerations at similar small body destinations. These data can also be applied for gaining an understanding of pertinent small body physical characteristics that would also be beneficial for formulating future impact mitigation procedures. Small Body Strategic Knowledge Gaps: For the past several years NASA has been interested in identifying the key SKGs related to future human destinations. These SKGs highlight the various unknowns and/or data gaps of targets that the science and engineering communities would like to have filled in prior to committing crews to explore the Solar System. An action team from the Small Bodies Assessment Group (SBAG) was formed specifically to identify the small body SKGs under the direction of the Human Exploration and Operations Missions Directorate (HEOMD), given NASA's recent interest in NEAs and the Martian moons as potential human destinations. The action team organized the SKGs into four broad themes: 1) Identify human mission targets; 2) Understand how to work on and interact with the small body surface; 3) Understand the small body environment and its potential risk/benefit to crew, systems, and operational assets; and 4) Understand the small body resource potential. Of these four SKG themes, the first three have significant overlap with planetary defense considerations. The data obtained from investigations of small body physical characteristics under these three themes can be directly applicable to planetary defense initiatives. Conclusions: Missions to investigate small bodies can address small body strategic knowledge gaps and contribute to the overall success for human exploration missions to asteroids and the Martian moons. In addition, such reconnaissance of small bodies can also provide a wealth of information relevant to the science and planetary defense of NEAs.

  18. Asteroid, Lunar and Planetary Regolith Management A Layered Engineering Defense

    NASA Technical Reports Server (NTRS)

    Wagner, Sandra

    2014-01-01

    During missions on asteroid and lunar and planetary surfaces, space systems and crew health may be degraded by exposure to dust and dirt. Furthermore, for missions outside the Earth-Moon system, planetary protection must be considered in efforts to minimize forward and backward contamination. This paper presents an end-to-end approach to ensure system reliability, crew health, and planetary protection in regolith environments. It also recommends technology investments that would be required to implement this layered engineering defense.

  19. Calculation methods for estimating the prospects of a space experiment by means of impact by asteroid Apophis on the Moon surface

    NASA Astrophysics Data System (ADS)

    Ostrik, A. V.; Kazantsev, A. M.

    2018-01-01

    The problem of principal change of asteroid 99952 (Apophis) orbit is formulated. Aim of this change is the termination of asteroid motion in Solar system. Instead of the passive rescue tactics from asteroid threat, an option is proposed for using the asteroid for setting up a large-scale space experiment on the impact interaction of the asteroid with the Moon. The scientific and methodical apparatus for calculating the possibility of realization, searching and justification the scientific uses of this space experiment is considered.

  20. The Remote Observing Working Group for the Asteroid Impact and Deflection Assessment (AIDA)

    NASA Astrophysics Data System (ADS)

    Rivkin, A. S.; Pravec, P.; Thomas, C. A.; Thirouin, A.; Snodgrass, C.; Green, S.; Licandro, J.; Sickafoose, A. A.; Erasmus, N.; Howell, E. S.; Osip, D.; Thomas-Osip, J.; Moskovitz, N.; Scheirich, P.; Oszkiewicz, D.; Richardson, D. C.; Polishook, D.; Ryan, W. H.; Busch, M. W.

    2017-09-01

    The Asteroid Impact and Deflection Assessment (AIDA) is a joint US-European mission concept designed to demonstrate the effectiveness of an kinetic impactor for planetary defense. Ground-based observing is a key component to AIDA and critical for its success. We present the observing campaign we have been conducting of the asteroid Didymos, the AIDA target, and plans for future work.

  1. The Asteroid Impact Mission

    NASA Astrophysics Data System (ADS)

    Carnelli, Ian; Galvez, Andres; Mellab, Karim

    2016-04-01

    The Asteroid Impact Mission (AIM) is a small and innovative mission of opportunity, currently under study at ESA, intending to demonstrate new technologies for future deep-space missions while addressing planetary defense objectives and performing for the first time detailed investigations of a binary asteroid system. It leverages on a unique opportunity provided by asteroid 65803 Didymos, set for an Earth close-encounter in October 2022, to achieve a fast mission return in only two years after launch in October/November 2020. AIM is also ESA's contribution to an international cooperation between ESA and NASA called Asteroid Impact Deflection Assessment (AIDA), consisting of two mission elements: the NASA Double Asteroid Redirection Test (DART) mission and the AIM rendezvous spacecraft. The primary goals of AIDA are to test our ability to perform a spacecraft impact on a near-Earth asteroid and to measure and characterize the deflection caused by the impact. The two mission components of AIDA, DART and AIM, are each independently valuable but when combined they provide a greatly increased scientific return. The DART hypervelocity impact on the secondary asteroid will alter the binary orbit period, which will also be measured by means of lightcurves observations from Earth-based telescopes. AIM instead will perform before and after detailed characterization shedding light on the dependence of the momentum transfer on the asteroid's bulk density, porosity, surface and internal properties. AIM will gather data describing the fragmentation and restructuring processes as well as the ejection of material, and relate them to parameters that can only be available from ground-based observations. Collisional events are of great importance in the formation and evolution of planetary systems, own Solar System and planetary rings. The AIDA scenario will provide a unique opportunity to observe a collision event directly in space, and simultaneously from ground-based optical and radar facilities. For the first time, an impact experiment at asteroid scale will be performed with accurate knowledge of the precise impact conditions and also the impact outcome, together with information on the physical properties of the target, ultimately validating at appropriate scales our knowledge of the process and impact simulations. AIM's important technology demonstration component includes a deep-space optical communication terminal and inter-satellite network with two CubeSats deployed in the vicinity of the Didymos system and a lander on the surface of the secondary. To achieve a low-cost objective AIM's technology and scientific payload are being combined to support both close-proximity navigation and scientific investigations. AIM will demonstrate the capability to achieve a small spacecraft design with a very large technological and scientific mission return.

  2. Large-Scale Experimental Planetary Science Meets Planetary Defense: Deorbiting an Asteroidal Satellite

    NASA Technical Reports Server (NTRS)

    Cintala, M. J.; Durda, D. D.; Housen, K. R.

    2005-01-01

    Other than remote-sensing and spacecraft-derived data, the only information that exists regarding the physical and chemical properties of asteroids is that inferred through calculations, numerical simulations, extrapolation of experiments, and meteorite studies. Our understanding of the dynamics of accretion of planetesimals, collisional disruption of asteroids, and the macroscopic, shock-induced modification of the surfaces of such small objects is also, for the most part, founded on similar inferences. While considerable strides have been made in improving the state of asteroid science, too many unknowns remain to assert that we understand the parameters necessary for the more practical problem of deflecting an asteroid or asteroid pair on an Earth-intersecting trajectory. Many of these deficiencies could be reduced or eliminated by intentionally deorbiting an asteroidal satellite and monitoring the resulting collision between it and the primary asteroid, a capability that is well within the limitations of current technology.

  3. 77 FR 71178 - Termination of Department of Defense Federal Advisory Committees

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-29

    ... DEPARTMENT OF DEFENSE Office of the Secretary Termination of Department of Defense Federal Advisory Committees AGENCY: Department of Defense. ACTION: Termination of Federal Advisory Committee..., the Department of Defense gives notice that it is terminating the Chief of Naval Operations Executive...

  4. Multiple main-belt asteroid mission options for a Mariner Mark II spacecraft

    NASA Astrophysics Data System (ADS)

    Sauer, Carl G., Jr.; Yen, Chen-Wan L.

    This paper presents the trajectory options available for a MMII spacecraft mission to asteroids and introduces systematic methods of uncovering attractive mission opportunities. The analysis presented considers multiple synchronous gravity assists of Mars and introduces a terminal resonant or phasing orbit; a concept useful for both increasing the number of asteroid rendezvous targets attainable during a launch opportunity, and also in increasing the number of potential asteroid flybys. Systematic examinations of the requirements for superior asteroidal alignments are made and a comprehensive set of asteroid rendezvous opportunities for the 1998 to 2010 period are presented. Examples of candidate missions involving one or more rendezvous and several flybys are also presented.

  5. Multiple main-belt asteroid mission options for a Mariner Mark II spacecraft

    NASA Technical Reports Server (NTRS)

    Sauer, Carl G., Jr.; Yen, Chen-Wan L.

    1990-01-01

    This paper presents the trajectory options available for a MMII spacecraft mission to asteroids and introduces systematic methods of uncovering attractive mission opportunities. The analysis presented considers multiple synchronous gravity assists of Mars and introduces a terminal resonant or phasing orbit; a concept useful for both increasing the number of asteroid rendezvous targets attainable during a launch opportunity, and also in increasing the number of potential asteroid flybys. Systematic examinations of the requirements for superior asteroidal alignments are made and a comprehensive set of asteroid rendezvous opportunities for the 1998 to 2010 period are presented. Examples of candidate missions involving one or more rendezvous and several flybys are also presented.

  6. 76 FR 43675 - Termination of Department of Defense Federal Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-21

    ... DEPARTMENT OF DEFENSE Office of the Secretary Termination of Department of Defense Federal Advisory Committee AGENCY: Department of Defense. ACTION: Termination of Federal Advisory Committee....C. 552b), effective June 22, 2011 the Department of Defense gives notice that it is terminating the...

  7. Asteroid Redirect Mission: Update on Planetary Defense Demonstration and Small Bodies Benefits and Community Interaction

    NASA Astrophysics Data System (ADS)

    Reeves, D.; Mazanek, D. D.; Abell, P. A.; Brophy, J. R.; Chodas, P. W.; Cichy, B. D.

    2016-12-01

    The National Aeronautics and Space Administration (NASA) is developing the Asteroid Redirect Mission (ARM) to robotically visit a large near-Earth asteroid (NEA), collect a multi-ton boulder and regolith samples from its surface, demonstrate the enhanced gravity tractor (EGT) planetary defense technique, return the asteroidal material to a stable orbit around the Moon, and explore the returned material with a crewed mission in the mid-2020s. Recent analysis of the EGT has led to a change in the robotic baseline operations from a halo orbit, to an in-line stand-off. This study took into account the uncertainties in size and mass of the current reference target (2008 EV5), the desire to be able to perform the EGT operations with the collected boulder augmenting the spacecraft mass or with the spacecraft alone, the assumed capability of the ARM solar electric propulsion (SEP) system, and the extensibility to future planetary defense missions. This presentation will cover the findings that led to this change in the baseline, as well as the benefits that this EGT demonstration will provide. ARM is a capability and technology demonstration mission, which will also benefit our understanding of small bodies in the areas of science, planetary defense, and asteroidal resources and in-situ resource utilization (ISRU). The synergistic benefits of both the robotic and crewed segments will be discussed in addition to describing ARM's interaction with communities that are interested in small bodies, including: the Formulation Assessment and Support Team (FAST) effort, the Small Bodies Assessment Group (SBAG) Special Action Team (SAT) effort, and the upcoming Investigation Team (IT). The IT, which is expected to be announced in the spring of 2017, will assist the ARM project in the definition, design, development, and operations phases of the ARRM with the goal of maximizing the probability of mission success and the knowledge return from the mission.

  8. Common Infrastructure for Neo Scientific and Planetary Defense Missions

    NASA Technical Reports Server (NTRS)

    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.

  9. The NEAR Spacecraft's Flyby of Asteroid 253 Mathilde

    NASA Technical Reports Server (NTRS)

    Yeomans, D. K.; Barriot, J. P.; Dunham, D. W.; Farquhar, R. W.; Helfrich, C. E.; Konopliv, A. S.; McAdams, J. V.; Miller, J. K.; Owen, W. M., Jr.; Scheeres, D. J.; hide

    1997-01-01

    The Terminal navigation of the NEAR spacecraft during its close flyby of asteroid 253 Mathilde involved coordinated efforts first to determine the heliocentric orbits of the spacecraft and Mathilde and then to determine the relative trajectory of the spacecraft with respect to Mathilde.

  10. Analysis of Potentially Hazardous Asteroids

    NASA Technical Reports Server (NTRS)

    Arnold, J. O.; Burkhard, C. D.; Dotson, J. L.; Prabhu, D. K.; Mathias, D. L.; Aftosmis, M. J.; Venkatapathy, Ethiraj; Morrison, D. D.; Sears, D. W. G.; Berger, M. J.

    2015-01-01

    The National Aeronautics and Space Administration initiated a new project focused on Planetary Defense on October 1, 2014. The new project is funded by NASAs Near Earth Object Program (Lindley Johnson, Program Executive). This presentation describes the objectives, functions and plans of four tasks encompassed in the new project and their inter-relations. Additionally, this project provides for outreach to facilitate partnerships with other organizations to help meet the objectives of the planetary defense community. The four tasks are (1) Characterization of Near Earth Asteroids, (2) Physics-Based Modeling of Meteor Entry and Breakup (3) Surface Impact Modeling and (4) Physics-Based Impact Risk Assessment.

  11. Deflection Missions for Asteroid 2011 AG5

    NASA Technical Reports Server (NTRS)

    Grebow, Daniel; Landau, Damon; Bhaskaran, Shyam; Chodas, Paul; Chesley, Steven; Yeomans, Don; Petropoulos, Anastassios; Sims, Jon

    2012-01-01

    The recently discovered asteroid 2011 AG5 currently has a 1-in-500 chance of impacting Earth in 2040. In this paper, we discuss the potential of future observations of the asteroid and their effects on the asteroid's orbital uncertainty. Various kinetic impactor mission scenarios, relying on both conventional chemical as well as solar-electric propulsion, are presented for deflecting the course of the asteroid safely away from Earth. The times for the missions range from pre-keyhole passage (pre-2023), and up to five years prior to the 2040 Earth close approach. We also include a brief discussion on terminal guidance, and contingency options for mission planning.

  12. A new terminal guidance sensor system for asteroid intercept or rendezvous missions

    NASA Astrophysics Data System (ADS)

    Lyzhoft, Joshua; Basart, John; Wie, Bong

    2016-02-01

    This paper presents the initial conceptual study results of a new terminal guidance sensor system for asteroid intercept or rendezvous missions, which explores the use of visual, infrared, and radar devices. As was demonstrated by NASA's Deep Impact mission, visual cameras can be effectively utilized for hypervelocity intercept terminal guidance for a 5 kilometer target. Other systems such as Raytheon's EKV (Exoatmospheric Kill Vehicle) employ a different scheme that utilizes infrared target information to intercept ballistic missiles. Another example that uses infrared information is the NEOWISE telescope, which is used for asteroid detection and tracking. This paper describes the signal-to-noise ratio estimation problem for infrared sensors, minimum and maximum range of detection, and computational validation using GPU accelerated simulations. Small targets (50-100 m in diameter) are considered, and scaled polyhedron models of known objects, such as the Rosetta mission's Comet 67P/Churyumov-Gerasimenko, 101,955 Bennu, target of the OSIRIS-REx mission, and asteroid 433 Eros, are utilized. A parallelized ray tracing algorithm to simulate realistic surface-to-surface shadowing of a given celestial body is developed. By using the simulated models and parameters given from the formulation of the different sensors, impact mission scenarios are used to verify the feasibility for intercepting a small target.

  13. Asteroid Retrieval Mission Concept - Trailblazing Our Future in Space and Helping to Protect Us from Earth Impactors

    NASA Technical Reports Server (NTRS)

    Mazanek, Daniel D.; Brohpy, John R.; Merrill, Raymond G.

    2013-01-01

    The Asteroid Retrieval Mission (ARM) is a robotic mission concept with the goal of returning a small (7 m diameter) near-Earth asteroid (NEA), or part of a large NEA, to a safe, stable orbit in cislunar space using a 50 kW-class solar electric propulsion (SEP) robotic spacecraft (40 kW available to the electric propulsion system) and currently available technologies. The mass of the asteroidal material returned from this mission is anticipated to be up to 1,000 metric tons, depending on the orbit of the target NEA and the thrust-to-weight and control authority of the SEP spacecraft. Even larger masses could be returned in the future as technological capability and operational experience improve. The use of high-power solar electric propulsion is the key enabling technology for this mission concept, and is beneficial or enabling for a variety of space missions and architectures where high-efficiency, low-thrust transfers are applicable. Many of the ARM operations and technologies could also be applicable to, or help inform, planetary defense efforts. These include the operational approaches and systems associated with the NEA approach, rendezvous, and station-keeping mission phases utilizing a low-thrust, high-power SEP spacecraft, along with interacting with, capturing, maneuvering, and processing the massive amounts of material associated with this mission. Additionally, the processed materials themselves (e.g., high-specific impulse chemical propellants) could potentially be used for planetary defense efforts. Finally, a ubiquitous asteroid retrieval and resource extraction infrastructure could provide the foundation of an on call planetary defense system, where a SEP fleet capable of propelling large masses could deliver payloads to deflect or disrupt a confirmed impactor in an efficient and timely manner.

  14. NASA's Asteroid Redirect Mission: Overview and Status

    NASA Astrophysics Data System (ADS)

    Abell, Paul; Gates, Michele; Johnson, Lindley; Chodas, Paul; Brophy, John; Mazanek, Dan; Muirhead, Brian

    A major element of the National Aeronautics and Space Administration’s (NASA) new Asteroid Initiative is the Asteroid Redirect Mission (ARM). This concept was first proposed in 2011 during a feasibility study at the Keck Institute for Space Studies (KISS)[1] and is under consideration for implementation by NASA. The ARM involves sending a high-efficiency (ISP 3000 s), high-power (40 kW) solar electric propulsion (SEP) robotic vehicle that leverages technology developed by NASA’s Space Technology Mission Directorate (STMD) to rendezvous with a near-Earth asteroid (NEA) and return asteroidal material to a stable lunar distant retrograde orbit (LDRO)[2]. There are two mission concepts currently under study, one that captures an entire 7 - 10 meter mean diameter NEA[3], and another that retrieves a 1 - 10 meter mean diameter boulder from a 100+ meter class NEA[4]. Once the retrieved asteroidal material is placed into the LDRO, a two person crew would launch aboard an Orion capsule to rendezvous and dock with the robotic SEP vehicle. After docking, the crew would conduct two extra-vehicular activities (EVA) to collect asteroid samples and deploy instruments prior to Earth return. The crewed portion of the mission is expected to last approximately 25 days and would represent the first human exploration mission beyond low-Earth orbit (LEO) since the Apollo program. The ARM concept leverages NASA’s activities in Human Exploration, Space Technology, and Planetary Defense to accomplish three primary objectives and several secondary objectives. The primary objective relevant to Human Exploration is to gain operational experience with vehicles, systems, and components that will be utilized for future deep space exploration. In regard to Space Technology, the ARM utilizes advanced SEP technology that has high power and long duration capabilities that enable future missions to deep space destinations, such as the Martian system. With respect to Planetary Defense, the ARM mission will utilize an enhanced NEA observation campaign that will detect, track, and characterize both spacecraft mission targets and potentially hazardous asteroids that may threaten Earth in the future. Potential secondary objectives for ARM include planetary defense demonstrations at the NEA, conducting planetary science (both during the robotic and crewed mission segments), and encouraging commercial and international partnership opportunities. References [1] J. Brophy et al., “Asteroid Retrieval Feasibility Study,” Keck Institute for Space Studies Report, April 2012. [2] N. Strange et al., “Overview of Mission Design for NASA Asteroid Redirect Robotic Mission Concept,” presented at the 33rd International Electric Propulsion Conference, The George Washington University, Washington, D.C., October 2013. [3] B. Muirhead, J. Brophy “Asteroid Redirect Robotic Mission Feasibility Study,” presented at IEEE Aerospace Conference, Big Sky, Montana, March 2014. [4] Mazenek et al., “Asteroid Redirect Robotic Mission: Alternate Concept Overview”, American Institute of Aeronautics and Astronautics, Space 2014 Conference, San Diego, California, August 2014.

  15. Maturation of the Asteroid Threat Assessment Project

    NASA Technical Reports Server (NTRS)

    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.

  16. 32 CFR 33.44 - Termination for convenience.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 1 2014-07-01 2014-07-01 false Termination for convenience. 33.44 Section 33.44 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE DoD GRANT AND AGREEMENT... GOVERNMENTS Post-Award Requirements Reports, Records, Retention, and Enforcement § 33.44 Termination for...

  17. 32 CFR 33.44 - Termination for convenience.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 1 2012-07-01 2012-07-01 false Termination for convenience. 33.44 Section 33.44 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE DoD GRANT AND AGREEMENT... GOVERNMENTS Post-Award Requirements Reports, Records, Retention, and Enforcement § 33.44 Termination for...

  18. 32 CFR 33.44 - Termination for convenience.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 1 2010-07-01 2010-07-01 false Termination for convenience. 33.44 Section 33.44 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE DoD GRANT AND AGREEMENT... GOVERNMENTS Post-Award Requirements Reports, Records, Retention, and Enforcement § 33.44 Termination for...

  19. 32 CFR 33.44 - Termination for convenience.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 1 2011-07-01 2011-07-01 false Termination for convenience. 33.44 Section 33.44 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE DoD GRANT AND AGREEMENT... GOVERNMENTS Post-Award Requirements Reports, Records, Retention, and Enforcement § 33.44 Termination for...

  20. 32 CFR 33.44 - Termination for convenience.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 1 2013-07-01 2013-07-01 false Termination for convenience. 33.44 Section 33.44 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE DoD GRANT AND AGREEMENT... GOVERNMENTS Post-Award Requirements Reports, Records, Retention, and Enforcement § 33.44 Termination for...

  1. Planetary Defense From Space: Part 1-Keplerian Theory

    NASA Astrophysics Data System (ADS)

    Maccone, Claudio

    A system of two space bases housing missiles is proposed to achieve the Planetary Defense of the Earth against dangerous asteroids and comets. We show that the layout of the Earth-Moon system with the five relevant Lagrangian (or libration) points in space leads naturally to only one, unmistakable location of these two space bases within the sphere of influence of the Earth. These locations are at the two Lagrangian points L1 (in between the Earth and the Moon) and L3 (in the direction opposite to the Moon from the Earth). We show that placing bases of missiles at L1 and L3 would cause those missiles to deflect the trajectory of asteroids by hitting them orthogonally to their impact trajectory toward the Earth, so as to maximize their deflection. We show that the confocal conics are the best class of trajectories fulfilling this orthogonal deflection requirement. An additional remark is that the theory developed in this paper is just a beginning of a larger set of future research work. In fact, while in this paper we only develop the Keplerian analytical theory of the Optimal Planetary Defense achievable from the Earth-Moon Lagrangian points L1 and L3, much more sophisticated analytical refinements would be needed to: Take into account many perturbation forces of all kinds acting on both the asteroids and missiles shot from L1 and L3; add more (non-optimal) trajectories of missiles shot from either the Lagrangian points L4 and L5 of the Earth-Moon system or from the surface of the Moon itself; encompass the full range of missiles currently available to the US (and possibly other countries) so as to really see "which asteroids could be diverted by which missiles", even in the very simplified scheme outlined here. Outlined for the first time in February 2002, our Confocal Planetary Defense concept is a Keplerian Theory that proved simple enough to catch the attention of scholars, representatives of the US Military and popular writers. These developments could possibly mark the beginning of an "all embracing" mathematical vision of Planetary Defense beyond all learned activities, dramatic movies and unknown military plans covered by secret.

  2. Deflection by Kinetic Impact or Nuclear Ablation: Sensitivity to Asteroid Properties

    NASA Astrophysics Data System (ADS)

    Bruck Syal, M.

    2015-12-01

    Impulsive deflection of a threatening asteroid can be achieved by deploying either a kinetic impactor or a standoff nuclear device to impart a modest velocity change to the body. Response to each of these methods is sensitive to the individual asteroid's characteristics, some of which may not be well constrained before an actual deflection mission. Numerical simulations of asteroid deflection, using both hypervelocity impacts and nuclear ablation of the asteroid's surface, provide detailed information on asteroid response under a range of initial conditions. Here we present numerical results for the deflection of asteroids by both kinetic and nuclear methods, focusing on the roles of target body composition, strength, porosity, rotational state, shape, and internal structure. These results provide a framework for evaluating the planetary defense-related value of future asteroid characterization missions and capture some of the uncertainty that may be present in a real threat scenario. Part of this work was funded by the Laboratory Directed Research and Development Program at LLNL under project tracking code 12-ERD-005, performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-675914.

  3. The Asteroid Impact and Deflection Assessment Mission and its Potential Contributions to Human Exploration of Asteroids

    NASA Technical Reports Server (NTRS)

    Abell, Paul A.; Rivkin, Andy S.

    2014-01-01

    The joint ESA and NASA Asteroid Impact and Deflection Assessment (AIDA) mission will directly address aspects of NASA's Asteroid Initiative and will contribute to future human exploration. The NASA Asteroid Initiative is comprised of two major components: the Grand Challenge and the Asteroid Mission. The first component, the Grand Challenge, focuses on protecting Earth's population from asteroid impacts by detecting potentially hazardous objects with enough warning time to either prevent them from impacting the planet, or to implement civil defense procedures. The Asteroid Mission, involves sending astronauts to study and sample a near-Earth asteroid (NEA) prior to conducting exploration missions of the Martian system, which includes Phobos and Deimos. AIDA's primary objective is to demonstrate a kinetic impact deflection and characterize the binary NEA Didymos. The science and technical data obtained from AIDA will aid in the planning of future human exploration missions to NEAs and other small bodies. The dual robotic missions of AIDA, ESA's Asteroid Impact Monitor (AIM) and NASA's Double Asteroid Redirection Test (DART), will provide a great deal of technical and engineering data on spacecraft operations for future human space exploration while conducting in-depth scientific examinations of the binary target Didymos both prior to and after the kinetic impact demonstration. The knowledge gained from this mission will help identify asteroidal physical properties in order to maximize operational efficiency and reduce mission risk for future small body missions. The AIDA data will help fill crucial strategic knowledge gaps concerning asteroid physical characteristics that are relevant for human exploration considerations at similar small body destinations.

  4. 75 FR 30002 - Federal Advisory Committee; Defense Task Force on Sexual Assault in the Military Services

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-28

    ... DEPARTMENT OF DEFENSE Office of the Secretary Federal Advisory Committee; Defense Task Force on Sexual Assault in the Military Services AGENCY: Department of Defense (DoD). ACTION: Termination of... Department of Defense gives notice that it is terminating the Defense Task Force on Sexual Assault in the...

  5. 32 CFR 219.123 - Early termination of research support: Evaluation of applications and proposals.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Early termination of research support: Evaluation of applications and proposals. 219.123 Section 219.123 National Defense Department of Defense....123 Early termination of research support: Evaluation of applications and proposals. (a) The...

  6. 32 CFR 219.123 - Early termination of research support: Evaluation of applications and proposals.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 2 2011-07-01 2011-07-01 false Early termination of research support: Evaluation of applications and proposals. 219.123 Section 219.123 National Defense Department of Defense....123 Early termination of research support: Evaluation of applications and proposals. (a) The...

  7. 75 FR 18487 - Committee Termination and Committee Establishment-Department of Defense Federal Advisory Committees

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-12

    ... DEPARTMENT OF DEFENSE Office of the Secretary Committee Termination and Committee Establishment--Department of Defense Federal Advisory Committees AGENCY: Department of Defense (DoD). ACTION: Committee... Department of Defense announces: the establishment of the Board of Advisors to the Presidents of the Naval...

  8. Linear Covariance Analysis For Proximity Operations Around Asteroid 2008 EV5

    NASA Technical Reports Server (NTRS)

    Wright, Cinnamon A.; Bhatt, Sagar; Woffinden, David; Strube, Matthew; D'Souza, Chris

    2015-01-01

    The NASA initiative to collect an asteroid, the Asteroid Robotic Redirect Mission (ARRM), is currently investigating the option of retrieving a boulder from an asteroid, demonstrating planetary defense with an enhanced gravity tractor technique, and returning it to a lunar orbit. Techniques for accomplishing this are being investigated by the Satellite Servicing Capabilities Office (SSCO) at NASA GSFC in collaboration with JPL, NASA JSC, LaRC, and Draper Laboratory, Inc. Two critical phases of the mission are the descent to the boulder and the Enhanced Gravity Tractor demonstration. A linear covariance analysis is done for these phases to assess the feasibility of these concepts with the proposed design of the sensor and actuator suite of the Asteroid Redirect Vehicle (ARV). The sensor suite for this analysis includes a wide field of view camera, LiDAR, and an IMU. The proposed asteroid of interest is currently the C-type asteroid 2008 EV5, a carbonaceous chondrite that is of high interest to the scientific community. This paper presents an overview of the linear covariance analysis techniques and simulation tool, provides sensor and actuator models, and addresses the feasibility of descending to the surface of the asteroid within allocated requirements as well as the possibility of maintaining a halo orbit to demonstrate the Enhanced Gravity Tractor technique.

  9. Near Earth Asteroid Characteristics for Asteroid Threat Assessment

    NASA Technical Reports Server (NTRS)

    Dotson, Jessie

    2015-01-01

    Information about the physical characteristics of Near Earth Asteroids (NEAs) is needed to model behavior during atmospheric entry, to assess the risk of an impact, and to model possible mitigation techniques. The intrinsic properties of interest to entry and mitigation modelers, however, rarely are directly measureable. Instead we measure other properties and infer the intrinsic physical properties, so determining the complete set of characteristics of interest is far from straightforward. In addition, for the majority of NEAs, only the basic measurements exist so often properties must be inferred from statistics of the population of more completely characterized objects. We will provide an assessment of the current state of knowledge about the physical characteristics of importance to asteroid threat assessment. In addition, an ongoing effort to collate NEA characteristics into a readily accessible database for use by the planetary defense community will be discussed.

  10. NASA Space Missions to Asteroids: Protecting the Earth from NEO Impacts

    NASA Technical Reports Server (NTRS)

    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.

  11. 32 CFR 634.22 - Termination or denial of registration.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Termination or denial of registration. 634.22 Section 634.22 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) LAW ENFORCEMENT AND CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Motor Vehicle Registration § 634.22 Termination or denial of registration...

  12. 32 CFR 37.925 - What requirements do I include for termination and enforcement?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... to Other Administrative Matters Termination and Enforcement § 37.925 What requirements do I include... 32 National Defense 1 2010-07-01 2010-07-01 false What requirements do I include for termination and enforcement? 37.925 Section 37.925 National Defense Department of Defense OFFICE OF THE SECRETARY...

  13. 32 CFR 37.925 - What requirements do I include for termination and enforcement?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... to Other Administrative Matters Termination and Enforcement § 37.925 What requirements do I include... 32 National Defense 1 2011-07-01 2011-07-01 false What requirements do I include for termination and enforcement? 37.925 Section 37.925 National Defense Department of Defense OFFICE OF THE SECRETARY...

  14. 32 CFR 842.99 - Compromise, termination, and suspension of collection.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Compromise, termination, and suspension of collection. 842.99 Section 842.99 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR... States (31 U.S.C. 3701, 3711-3719) § 842.99 Compromise, termination, and suspension of collection. This...

  15. CrossTalk. The Journal of Defense Software Engineering. Volume 26, Number 1

    DTIC Science & Technology

    2013-02-01

    ANTS) mission that may be used to explore the asteroid belt. Basically, the mission entails 1,000 two-pound autonomous space vehicles that will be...be used to collect data from asteroids that will be periodically transmitted back to earth. For autonomous operation, the ANTS will need to...priory information. In other words, these indicators are used to support any one of a number of situation assessments that have been predeter- mined

  16. Space Studies of the Earth-Moon System, Planets, and Small Bodies of the Solar System (B) Past, Present and Future of Small Body Science and Exploration (B0.4)

    NASA Technical Reports Server (NTRS)

    Abell, Paul; Mazanek, Dan; Reeves, Dan; Chodas, Paul; Gates, Michele; Johnson, Lindley; Ticker, Ronald

    2016-01-01

    To achieve its long-term goal of sending humans to Mars, the National Aeronautics and Space Administration (NASA) plans to proceed in a series of incrementally more complex human space flight missions. Today, human flight experience extends only to Low- Earth Orbit (LEO), and should problems arise during a mission, the crew can return to Earth in a matter of minutes to hours. The next logical step for human space flight is to gain flight experience in the vicinity of the Moon. These cis-lunar missions provide a "proving ground" for the testing of systems and operations while still accommodating an emergency return path to the Earth that would last only several days. Cis-lunar mission experience will be essential for more ambitious human missions beyond the Earth-Moon system, which will require weeks, months, or even years of transit time. In addition, NASA has been given a Grand Challenge to find all asteroid threats to human populations and know what to do about them. Obtaining knowledge of asteroid physical properties combined with performing technology demonstrations for planetary defense provide much needed information to address the issue of future asteroid impacts on Earth. Hence the combined objectives of human exploration and planetary defense give a rationale for the Asteroid Re-direct Mission (ARM).

  17. 76 FR 19753 - Termination of Department of Defense Federal Advisory Committees

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-08

    ... DEPARTMENT OF DEFENSE Office of the Secretary Termination of Department of Defense Federal... Government in the Sunshine Act of 1976 (5 U.S.C. 552b), effective June 11, 2011 the Department of Defense...: Contact Jim Freeman, Deputy Advisory Committee Management Officer for the Department of Defense, 703-601...

  18. 77 FR 71403 - Termination of Department of Defense Federal Advisory Committees

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-30

    ... DEPARTMENT OF DEFENSE Office of the Secretary Termination of Department of Defense Federal... Government in the Sunshine Act of 1976 (5 U.S.C. 552b), effective October 5, 2012, the Department of Defense... CONTACT: Jim Freeman, Advisory Committee Management Officer for the Department of Defense, 703-692-5952...

  19. Boulder Capture System Design Options for the Asteroid Robotic Redirect Mission Alternate Approach Trade Study

    NASA Technical Reports Server (NTRS)

    Belbin, Scott P.; Merrill, Raymond G.

    2014-01-01

    This paper presents a boulder acquisition and asteroid surface interaction electromechanical concept developed for the Asteroid Robotic Redirect Mission (ARRM) option to capture a free standing boulder on the surface of a 100 m or larger Near Earth Asteroid (NEA). It details the down select process and ranking of potential boulder capture methods, the evolution of a simple yet elegant articulating spaceframe, and ongoing risk reduction and concept refinement efforts. The capture system configuration leverages the spaceframe, heritage manipulators, and a new microspine technology to enable the ARRM boulder capture. While at the NEA it enables attenuation of terminal descent velocity, ascent to escape velocity, boulder collection and restraint. After departure from the NEA it enables, robotic inspection, sample caching, and crew Extra Vehicular Activities (EVA).

  20. TC4 Observing Campaign: An Operational Test of NASA Planetary Defense Network

    NASA Astrophysics Data System (ADS)

    Reddy, V.; Kelley, M. S.; Landis, R. R.

    Impacts due to near-Earth objects ( 90% near-Earth asteroids, or NEAs, and 10% comets) are one of the natural hazards that can pose a great risk to life on Earth, but one that can potentially be mitigated, if the threat is detected with sufficient lead-time. While the probability of such an event is low, the outcome is so catastrophic that we are well justified in investing a modest effort to minimize this threat. Historically, asteroid impacts have altered the course of evolution on the Earth. In 2013 the Chelyabinsk meteor over Russia, which injured over 1600 people and caused $30M in damages, reinforced the importance of detecting and characterizing small NEAs that pose a greater threat than most large NEAs discovered so far. The NASA Planetary Defense Coordination Office (PDCO) was established to ensure the early detection, tracking and characterization of potentially hazardous objects (PHOs) and is the lead office for providing timely and accurate communications and coordination of U.S. Government planning for response to an actual impact threat. In an effort to test the operational readiness of all entities critical to planetary defense, the NASA PDCO is supporting a community-led exercise. The target of this exercise is 2012 TC4, a 20- meter diameter asteroid that is currently expected to pass by the Earth over Antarctica on Oct. 12, 2017 at a distance of only 2.3 Earth radii. The goal of the TC4 Observing Campaign is to recover, track, and characterize 2012 TC4 as a potential impactor in order to exercise the entire Planetary Defense system from observations, modeling, prediction, and communication. The paper will present an overview of the campaign and summarize early results from the exercise.

  1. 32 CFR 219.113 - Suspension or termination of IRB approval of research.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 2 2014-07-01 2014-07-01 false Suspension or termination of IRB approval of research. 219.113 Section 219.113 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) MISCELLANEOUS PROTECTION OF HUMAN SUBJECTS § 219.113 Suspension or...

  2. Two radars for AIM mission: A direct observation of the asteroid's structure from deep interior to regolith

    NASA Astrophysics Data System (ADS)

    Herique, A.; Ciarletti, V.

    2015-10-01

    Our knowledge of the internal structure of asteroids is, so far, indirect - relying entirely on inferences from remote sensing observations of the surface, and theoretical modeling. What are the bulk properties of the regolith and deep interior? And what are the physical processes that shape their internal structures? Direct measurements are needed to provide answers that will directly improve our ability to understand and model the mechanisms driving Near Earth Asteroids (NEA) for the benefit of science as well as for planetary defense or exploration. Radar tomography is the only technique to characterize internal structure from decimetric scale to global scale. This paper reviews the benefits of direct measurement of the asteroid interior. Then the radar concepts for both deep interior and shallow subsurface are presented and the radar payload proposed for the AIDA/AIM mission is outlined.

  3. Probabilistic Asteroid Impact Risk Assessment for the Hypothetical PDC17 Impact Exercise

    NASA Technical Reports Server (NTRS)

    Wheeler, Lorien; Mathias, Donovan

    2017-01-01

    Performing impact risk assessment for the 2017 Planetary Defense Conference (PDC17) hypothetical impact exercise, to take place at the PDC17 conference, May 15-20, 2017. Impact scenarios and trajectories are developed and provided by NASA's Near Earth Objects Office at JPL (Paul Chodas). These results represent purely hypothetical impact scenarios, and do not reflect any known asteroid threat. Risk assessment was performed using the Probabilistic Asteroid Impact Risk (PAIR) model developed by the Asteroid Threat Assessment Project (ATAP) at NASA Ames Research Center. This presentation includes sample results that may be presented or used in discussions during the various stages of the impact exercisecenter dot Some cases represent alternate scenario options that may not be used during the actual impact exercise at the PDC17 conference. Updates to these initial assessments and/or additional scenario assessments may be performed throughout the impact exercise as different scenario options unfold.

  4. Target selection for a hypervelocity asteroid intercept vehicle flight validation mission

    NASA Astrophysics Data System (ADS)

    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.

  5. Asteroid Redirect Mission - Next Major stepping-stone to Human Exploration of NEOs and beyond

    NASA Astrophysics Data System (ADS)

    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.

  6. An Overview of NASA's Asteroid Redirect Mission (ARM) Concept

    NASA Technical Reports Server (NTRS)

    Abell, P. A.; Mazanek, D. D.; Reeves, D. M.; Chodas, P. W.; Gates, M. M.; Johnson, L. N.; Ticker, R. L.

    2016-01-01

    The National Aeronautics and Space Administration (NASA) is developing the Asteroid Redirect Mission (ARM) as a capability demonstration for future human exploration, including use of high-power solar electric propulsion, which allows for the efficient movement of large masses through deep space. The ARM will also demonstrate the capability to conduct proximity operations with natural space objects and crewed operations beyond the security of quick Earth return. The Asteroid Redirect Robotic Mission (ARRM), currently in formulation, will visit a large near-Earth asteroid (NEA), collect a multi-ton boulder from its surface, conduct a demonstration of a slow push planetary defense technique, and redirect the multi-ton boulder into a stable orbit around the Moon. Once returned to cislunar space in the mid-2020s, astronauts aboard an Orion spacecraft will dock with the robotic vehicle to explore the boulder and return samples to Earth. The ARM is part of NASA's plan to advance technologies, capabilities, and spaceflight experience needed for a human mission to the Martian system in the 2030s. The ARM and subsequent availability of the asteroidal material in cis-lunar space, provide significant opportunities to advance our knowledge of small bodies in the synergistic areas of science, planetary defense, and in-situ resource utilization (ISRU). NASA established the Formulation Assessment and Support Team (FAST), comprised of scientists, engineers, and technologists, which supported ARRM mission requirements formulation, answered specific questions concerning potential target asteroid physical properties, and produced a publically available report. The ARM Investigation Team is being organized to support ARM implementation and execution. NASA is also open to collaboration with its international partners and welcomes further discussions. An overview of the ARM robotic and crewed segments, including mission requirements, NEA targets, and mission operations, and a discussion of potential opportunities for participation with the ARM will be provided.

  7. Overview and Updated Status of the Asteroid Redirect Mission (ARM)

    NASA Astrophysics Data System (ADS)

    Abell, Paul; Mazanek, Daniel D.; Reeves, David M.; Chodas, Paul; Gates, Michele; Johnson, Lindley N.; Ticker, Ronald

    2016-10-01

    The National Aeronautics and Space Administration (NASA) is developing a mission to visit a large near-Earth asteroid (NEA), collect a multi-ton boulder and regolith samples from its surface, demonstrate a planetary defense technique known as the enhanced gravity tractor, and return the asteroidal material to a stable orbit around the Moon. Once returned to cislunar space in the mid-2020s, astronauts will explore the boulder and return to Earth with samples. This Asteroid Redirect Mission (ARM) is part of NASA's plan to advance the technologies, capabilities, and spaceflight experience needed for a human mission to the Martian system in the 2030s and other destinations, as well as provide other broader benefits. Subsequent human and robotic missions to the asteroidal material would also be facilitated by its return to cislunar space. Although ARM is primarily a capability demonstration mission (i.e., technologies and associated operations), there exist significant opportunities to advance our knowledge of small bodies in the synergistic areas of science, planetary defense, asteroidal resources and in-situ resource utilization (ISRU), and capability and technology demonstrations. Current plans are for the robotic mission to be launched in late 2021 with the crewed mission segment conducted using an Orion capsule via a Space Launch System rocket in 2026. In order to maximize the knowledge return from the mission, NASA is providing accommodations for payloads to be carried on the robotic segment of the mission and also organizing an ARM Investigation Team. The Investigation Team will be comprised of scientists, technologists, and other qualified and interested individuals from US industry, government, academia, and international institutions to help plan the implementation and execution of ARM. The presentation will provide a mission overview and the most recent update concerning the robotic and crewed segments of ARM, including the mission requirements, and potential NEA targets. Details about the mission operations for each segment will also be provided along with a discussion of the potential opportunities associated with the mission.

  8. Spacecraft Mission Design for the Mitigation of the 2017 PDC Hypothetical Asteroid Threat

    NASA Technical Reports Server (NTRS)

    Barbee, Brent W.; Sarli, Bruno V.; Lyzhoft, Josh; Chodas, Paul W.; Englander, Jacob A.

    2017-01-01

    This paper presents a detailed mission design analysis results for the 2017 Planetary Defense Conference (PDC) Hypothetical Asteroid Impact Scenario, documented at https:cneos.jpl.nasa.govpdcspdc17. The mission design includes campaigns for both reconnaissance (flyby or rendezvous) of the asteroid (to characterize it and the nature of the threat it poses to Earth) and mitigation of the asteroid, via kinetic impactor deflection, nuclear explosive device (NED) deflection, or NED disruption. Relevant scenario parameters are varied to assess the sensitivity of the design outcome, such as asteroid bulk density, asteroid diameter, momentum enhancement factor, spacecraft launch vehicle, and mitigation system type. Different trajectory types are evaluated in the mission design process from purely ballistic to those involving optimal midcourse maneuvers, planetary gravity assists, and/or low-thrust solar electric propulsion. The trajectory optimization is targeted around peak deflection points that were found through a novel linear numerical technique method. The optimization process includes constrain parameters, such as Earth departure date, launch declination, spacecraft, asteroid relative velocity and solar phase angle, spacecraft dry mass, minimum/maximum spacecraft distances from Sun and Earth, and Earth-spacecraft communications line of sight. Results show that one of the best options for the 2017 PDC deflection is solar electric propelled rendezvous mission with a single spacecraft using NED for the deflection.

  9. Comet/Asteroid Protection System (CAPS): A Space-Based System Concept for Revolutionizing Earth Protection and Utilization of Near-Earth Objects

    NASA Technical Reports Server (NTRS)

    Mazanek, Daniel D.; Roithmayr, Carlos M.; Antol, Jeffrey; Kay-Bunnell, Linda; Werner, Martin R.; Park, Sang-Young; Kumar, Renjith R.

    2002-01-01

    There exists an infrequent, but significant hazard to life and property due to impacting asteroids and comets. There is currently no specific search for long-period comets, smaller near-Earth asteroids, or smaller short-period comets. These objects represent a threat with potentially little or no warning time using conventional ground-based telescopes. These planetary bodies also represent a significant resource for commercial exploitation, long-term sustained space exploration, and scientific research. The Comet/Asteroid Protection System (CAPS) would expand the current detection effort to include long-period comets, as well as small asteroids and short-period comets capable of regional destruction. A space-based detection system, despite being more costly and complex than Earth-based initiatives, is the most promising way of expanding the range of detectable objects, and surveying the entire celestial sky on a regular basis. CAPS is a future spacebased system concept that provides permanent, continuous asteroid and comet monitoring, and rapid, controlled modification of the orbital trajectories of selected bodies. CAPS would provide an orbit modification system capable of diverting kilometer class objects, and modifying the orbits of smaller asteroids for impact defense and resource utilization. This paper provides a summary of CAPS and discusses several key areas and technologies that are being investigated.

  10. Integrated Blowoff and Breakup Calculations for Asteroid Deflection by Nuclear Ablation

    NASA Astrophysics Data System (ADS)

    Bruck Syal, M.; Owen, M.; Dearborn, D. S.; Miller, P. L.

    2016-12-01

    When the warning timing is short, hazardous asteroids or comets can only be deflected off of an Earth-impacting trajectory by a nuclear device [1]. Here we model asteroid response to a standoff nuclear explosion, a problem which requires sub-millimeter spatial resolution at the body's surface to fully capture x-ray energy deposition. The first stage of the calculation focuses on modeling blowoff momentum from vaporized material, using a problem domain confined to the uppermost surface of the asteroid. Once the blowoff momentum transfer process is complete, the problem is remapped into a coarser resolution and the remainder of the asteroid body is added to the calculation, so that asteroid response can be tracked over longer timescales. This two-stage approach enables an integrated assessment of both the efficacy of momentum delivery and damage incurred by the bulk of the asteroid. Investigating the degree of post-ablation fracture, fragmentation, and fragment dispersion is necessary for modeling the outcomes of cases intended to fully fragment and disperse the body (disruption), as well as cases where the bulk of the asteroid should remain intact (deflection). We begin with 500-m spherical asteroids but also extend our analysis to radar-derived asteroid shape models. [1] Dearborn, D.S.P., Miller, P.L., 2014. Deflecting or Disrupting a Threatening Object, in: Pelton, J.N., Allahdadi, F. (Eds.), Handbook of Cosmic Hazards and Planetary Defense, Springer. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52- 07NA27344. LLNL-ABS-699631.

  11. Thermal Tomography of Asteroid Surface Structure

    NASA Astrophysics Data System (ADS)

    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.

  12. THERMAL TOMOGRAPHY OF ASTEROID SURFACE STRUCTURE

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

    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

  13. 32 CFR 219.123 - Early termination of research support: Evaluation of applications and proposals.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 2 2014-07-01 2014-07-01 false Early termination of research support: Evaluation of applications and proposals. 219.123 Section 219.123 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) MISCELLANEOUS PROTECTION OF HUMAN SUBJECTS § 219...

  14. 48 CFR 249.105-1 - Termination status reports.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 3 2012-10-01 2012-10-01 false Termination status reports. 249.105-1 Section 249.105-1 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CONTRACT MANAGEMENT TERMINATION OF CONTRACTS General Principles 249.105-1...

  15. 48 CFR 249.105-1 - Termination status reports.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Termination status reports. 249.105-1 Section 249.105-1 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CONTRACT MANAGEMENT TERMINATION OF CONTRACTS General Principles 249.105-1...

  16. 48 CFR 249.105-1 - Termination status reports.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Termination status reports. 249.105-1 Section 249.105-1 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CONTRACT MANAGEMENT TERMINATION OF CONTRACTS General Principles 249.105-1...

  17. 48 CFR 249.105-1 - Termination status reports.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false Termination status reports. 249.105-1 Section 249.105-1 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CONTRACT MANAGEMENT TERMINATION OF CONTRACTS General Principles 249.105-1...

  18. 48 CFR 249.105-1 - Termination status reports.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 3 2013-10-01 2013-10-01 false Termination status reports. 249.105-1 Section 249.105-1 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CONTRACT MANAGEMENT TERMINATION OF CONTRACTS General Principles 249.105-1...

  19. AIDA DART asteroid deflection test: Planetary defense and science objectives

    NASA Astrophysics Data System (ADS)

    Cheng, Andrew F.; Rivkin, Andrew S.; Michel, Patrick; Atchison, Justin; Barnouin, Olivier; Benner, Lance; Chabot, Nancy L.; Ernst, Carolyn; Fahnestock, Eugene G.; Kueppers, Michael; Pravec, Petr; Rainey, Emma; Richardson, Derek C.; Stickle, Angela M.; Thomas, Cristina

    2018-08-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission is an international cooperation between NASA and ESA. NASA plans to provide the Double Asteroid Redirection Test (DART) mission which will perform a kinetic impactor experiment to demonstrate asteroid impact hazard mitigation. ESA proposes to provide the Hera mission which will rendezvous with the target to monitor the deflection, perform detailed characterizations, and measure the DART impact outcomes and momentum transfer efficiency. The primary goals of AIDA are (i) to demonstrate the kinetic impact technique on a potentially hazardous near-Earth asteroid and (ii) to measure and characterize the deflection caused by the impact. The AIDA target will be the binary asteroid (65803) Didymos, which is of spectral type Sq, with the deflection experiment to occur in October, 2022. The DART impact on the secondary member of the binary at ∼6 km/s changes the orbital speed and the binary orbit period, which can be measured by Earth-based observatories with telescope apertures as small as 1 m. The DART impact will in addition alter the orbital and rotational states of the Didymos binary, leading to excitation of eccentricity and libration that, if measured by Hera, can constrain internal structure of the target asteroid. Measurements of the DART crater diameter and morphology can constrain target properties like cohesion and porosity based on numerical simulations of the DART impact.

  20. Spacecraft Mission Design for the Mitigation of the 2017 PDC Hypothetical Asteroid Threat

    NASA Technical Reports Server (NTRS)

    Barbee, Brent W.; Sarli, Bruno V.; Lyzhoft, Joshua; Chodas, Paul W.; Englander, Jacob A.

    2017-01-01

    This paper presents a detailed mission design analysis results for the 2017 Planetary Defense Conference (PDC) Hypothetical Asteroid Impact Scenario, documented at https://cneos.jpl.nasa.gov/ pd/cs/pdc17/. The mission design includes campaigns for both reconnaissance (flyby or rendezvous) of the asteroid (to characterize it and the nature of the threat it poses to Earth) and mitigation of the asteroid, via kinetic impactor deflection, nuclear explosive device (NED) deflection, or NED disruption. Relevant scenario parameters are varied to assess the sensitivity of the design outcome, such as asteroid bulk density, asteroid diameter, momentum enhancement factor, spacecraft launch vehicle, and mitigation system type. Different trajectory types are evaluated in the mission design process from purely ballistic to those involving optimal midcourse maneuvers, planetary gravity assists, and/or lowthrust solar electric propulsion. The trajectory optimization is targeted around peak deflection points that were found through a novel linear numerical technique method. The optimization process includes constrain parameters, such as Earth departure date, launch declination, spacecraft/asteroid relative velocity and solar phase angle, spacecraft dry mass, minimum/maximum spacecraft distances from Sun and Earth, and Earth/spacecraft communications line of sight. Results show that one of the best options for the 2017 PDC deflection is solar electric propelled rendezvous mission with a single spacecraft using NED for the deflection

  1. Comet/Asteroid Protection System (CAPS): Preliminary Space-Based Concept and Study Results

    NASA Technical Reports Server (NTRS)

    Mazanek, Daniel D.; Roithmayr, Carlos M.; Antol, Jeffrey; Park, Sang-Young; Koons, Robert H.; Bremer, James C.; Murphy, Douglas G.; Hoffman, James A.; Kumar, Renjith R.; Seywald, Hans

    2005-01-01

    There exists an infrequent, but significant hazard to life and property due to impacting asteroids and comets. There is currently no specific search for long-period comets, smaller near-Earth asteroids, or smaller short-period comets. These objects represent a threat with potentially little or no warning time using conventional ground-based telescopes. These planetary bodies also represent a significant resource for commercial exploitation, long-term sustained space exploration, and scientific research. The Comet/Asteroid Protection System (CAPS) is a future space-based system concept that provides permanent, continuous asteroid and comet monitoring, and rapid, controlled modification of the orbital trajectories of selected bodies. CAPS would expand the current detection effort to include long-period comets, as well as small asteroids and short-period comets capable of regional destruction. A space-based detection system, despite being more costly and complex than Earth-based initiatives, is the most promising way of expanding the range of detectable objects, and surveying the entire celestial sky on a regular basis. CAPS would provide an orbit modification system capable of diverting kilometer class objects, and modifying the orbits of smaller asteroids for impact defense and resource utilization. This Technical Memorandum provides a compilation of key related topics and analyses performed during the CAPS study, which was performed under the Revolutionary Aerospace Systems Concepts (RASC) program, and discusses technologies that could enable the implementation of this future system.

  2. Asteroid approach covariance analysis for the Clementine mission

    NASA Technical Reports Server (NTRS)

    Ionasescu, Rodica; Sonnabend, David

    1993-01-01

    The Clementine mission is designed to test Strategic Defense Initiative Organization (SDIO) technology, the Brilliant Pebbles and Brilliant Eyes sensors, by mapping the moon surface and flying by the asteroid Geographos. The capability of two of the instruments available on board the spacecraft, the lidar (laser radar) and the UV/Visible camera is used in the covariance analysis to obtain the spacecraft delivery uncertainties at the asteroid. These uncertainties are due primarily to asteroid ephemeris uncertainties. On board optical navigation reduces the uncertainty in the knowledge of the spacecraft position in the direction perpendicular to the incoming asymptote to a one-sigma value of under 1 km, at the closest approach distance of 100 km. The uncertainty in the knowledge of the encounter time is about 0.1 seconds for a flyby velocity of 10.85 km/s. The magnitude of these uncertainties is due largely to Center Finding Errors (CFE). These systematic errors represent the accuracy expected in locating the center of the asteroid in the optical navigation images, in the absence of a topographic model for the asteroid. The direction of the incoming asymptote cannot be estimated accurately until minutes before the asteroid flyby, and correcting for it would require autonomous navigation. Orbit determination errors dominate over maneuver execution errors, and the final delivery accuracy attained is basically the orbit determination uncertainty before the final maneuver.

  3. 32 CFR 776.35 - Declining or terminating representation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 5 2013-07-01 2013-07-01 false Declining or terminating representation. 776.35 Section 776.35 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY MISCELLANEOUS... assignment or employment of other counsel, and surrendering papers and property to which the client is...

  4. 32 CFR 776.35 - Declining or terminating representation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 5 2011-07-01 2011-07-01 false Declining or terminating representation. 776.35 Section 776.35 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY MISCELLANEOUS... assignment or employment of other counsel, and surrendering papers and property to which the client is...

  5. 32 CFR 776.35 - Declining or terminating representation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 5 2014-07-01 2014-07-01 false Declining or terminating representation. 776.35 Section 776.35 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY MISCELLANEOUS... assignment or employment of other counsel, and surrendering papers and property to which the client is...

  6. 32 CFR 776.35 - Declining or terminating representation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 5 2010-07-01 2010-07-01 false Declining or terminating representation. 776.35 Section 776.35 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY MISCELLANEOUS... assignment or employment of other counsel, and surrendering papers and property to which the client is...

  7. 32 CFR 776.35 - Declining or terminating representation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 5 2012-07-01 2012-07-01 false Declining or terminating representation. 776.35 Section 776.35 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY MISCELLANEOUS... assignment or employment of other counsel, and surrendering papers and property to which the client is...

  8. 77 FR 8837 - Termination of the Department of Defense Web-Based TRICARE Assistance Program Demonstration

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-15

    ... DEPARTMENT OF DEFENSE Office of the Secretary Termination of the Department of Defense Web-Based..., entitled Web-Based TRICARE Assistance Program (TRIAP). The demonstration project uses existing health care support contracts (HCSC) to allow web-based behavioral health and related services including non-medical...

  9. Meteorites, Bolides and Comets: A Tale of Inconsistency

    NASA Astrophysics Data System (ADS)

    Jakes, P.; Padevet, V.

    1992-07-01

    Inhomogeneity of cometary nuclei has been established through the observed disruptions of comets [1] and through the determination of dust particle composition during the encounter of the Vega and Giotto satellites with comet Halley [2,3,4]. The raisin bread model of cometary nuclei [5,6] assumes the presence of solid (rock) and dust particle material set in the volatile rich, ice- cemented material. Rock material may contribute to the formation of dust particles. Gombosi and Houpis [5] argued that only the composition of dust particles derived from the icy, volatile component of the comet were analyzed and implied thus that the third cometary component present (raisins/rocks) has not been examined. The compositions of the cometary (Halley) dust and the interplanetary dust particles (IDPs) are "chondritic" (Blanford et al., 1988). It is difficult, therefore to estimate the proportion of cometary to asteroid-derived dust in near Earth space, e.g., among the IDPs [7] unless other criteria are available. Bolide multistation photographic tracking allows the determination of the orbital preencounter parameters of solid bodies (0.01-100,000 kg in mass) with the Earth, and allows us to classify them according to their ablation coefficient (tau), penetration depth into the atmosphere (PE), theoretical densities (sigma), and terminal velocities (V(sub)E). Four groups are recognized (Table 1). Three of the type I bolides were recovered as ordinary chondrites (Pribram, Lost City, and Innisfree). Ceplecha [8] has shown that 38% of bolides (fireballs) come from cometary orbits (11% from highly eccentric orbits typical of new comets), but most of the bolides (62%) originate at asteroidal orbits. Seven of the 14 known meteoric showers could be attributed to known comets: N,S Taurids to 1970 P/Encke, Lyrids to 1861 I Thatcher-Beaker, Perseids to 1862 III Swift-Tuttle- Simons, Orionids to 1835 III P/Halley, Draconids to 1946 V P/Giacobini-Zinner, Leonids to 1966 I Tempel-Tuttle, and Leo Minorids to 1739 Zanotti. Geminids were related to asteroid 3200 Phaeton, considered to be an "extinct comet." Spurny [9], using ablation coefficient and penetration depth criteria, found that Geminids (frequently) and Taurids (rarely) contain bolides of types I and II. This may indicate that meteoric showers from "comets" on AAA orbits contain some portion of "rocky" material comparable to chondrites. These observations revive Opik's (1963) idea that comets may be captured in the asteroid belt on AAA orbits and may contain (and supply) chondritic meteorites to the Earth [10]. If the relationship among large solid particles "native to the asteroid belt" and those from the outer solar system can be established, they can be scaled and applied to IDPs. We have studied the records of 292 bolides (Prairie and European networks) with measured terminal velocities. We attempt to use the terminal velocity, calculated density, estimated terminal mass, and mechanical strength to correlate features with the meteorite features. We compare the meteorite fall frequency [11] with the bolide features. Two extreme hypotheses (Table 1) are examined: (A) bolides of types IIIa and IIIb do not have equivalents among the meteorites and (B) all four bolide types have meteoritic equivalents, and only IDPs do not produce bolides (fireballs). If the entry parameters of meteoroids are similar, bodies with lower density should reach terminal velocity at higher altitudes than those with higher density. If it is assumed that fragmentation is the same for dense (I and II) and less dense bodies (IIIa and IIIb), the calculated terminal altitudes show that among the bolides exist materials with lower densities than those of recovered meteorites and that model A of the correlation between meteorite falls and bolide observations is likely [12]. If, however, the less dense bodies were more easily fragmented than denser bodies, the correlation is better for hypothesis B. Table 1, which in the hard copy appears here, shows fireball observations. Using the value of terminal velocities and the average value of ablation coefficients the terminal (residual) masses (m(sub)E) can be calculated. Among the bodies studied, 99 were heavier than 0.1 kg and 153 heavier than 0.01 kg. The parameter (m(sub)E) indicates the end of ablation in the atmosphere, but it cannot distinguish between meteoroids that were totally disintegrated and those genuinely decelerated. Similarly the calculated terminal altitudes and mechanical strength values do not provide a unequivocal interpretation. Correlation of bolide properties with meteorite falls could well be accommodated by the hypothesis B in which each bolide type has a meteorite equivalent. This has, however, some "outrageous" implications: comets may carry chondrites, icy dust balls do not produce fireballs; the extremely primitive carbon-rich particles represented by the IDPs do not form larger discrete bodies (fireballs) of "asteroidal" size; and the asteroid belt is a mixture of "native fractionated old bodies" together with the captured comets. Hypothesis B therefore contradicts the "established" scheme of the asteroid belt in which the non-differentiated meteorites (CI, CM, and CV) form the outer part of the asteroid belt, whereas the fractionated metamorphosed and igneous meteorites characterize the inner asteroids. References: [1] Whipple F. L., 1987, Phil. Trans. R. Soc. Lond., A 323, 339. [2] Dikov Yu. P. et al., 1991, Geochemistry International, 29, 33-38. [3] Kissel J., et al., 1986, Nature, 321, 326. [4] Solc M., et al., 1987, Publ. Astr. Inst. Czechosl., 67, 47. [5] Gombosi T. I. and Houpis H. L. F., 1986, Nature, 324, 43. [6] Delsemme A. H., 1977, Comets, asteroids, meteorites, Univ. of Toledo Press. [7] Gibson E. K., 1992, J. Geophys. Res., 97, E3 3865. [8] Ceplecha Z., 1988, Bull. Astr. Inst. Czech., 39, 221. [9] Spurny P., 1991, doc. diss., Astr. Inst. Czechosl. [10] Opik E. J., 1963, Adv. Astr. Astrophys., 2, 219. [11] Hutchinson R., et al., 1977, Appendix to Catalogue of Meteorites, British Museum, London. [12] Ceplecha Z. and McCrosky R. E., 1976, J. Geophys. Res., 81, 6257.

  10. 48 CFR 970.2672-2 - Requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Defense Nuclear Facility is terminated (except for a termination for cause) applies to management and... requirements set forth in subpart 926.71, Implementation of Section 3161 of the National Defense Authorization...

  11. 48 CFR 970.2672-2 - Requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Defense Nuclear Facility is terminated (except for a termination for cause) applies to management and... requirements set forth in subpart 926.71, Implementation of Section 3161 of the National Defense Authorization...

  12. 48 CFR 970.2672-2 - Requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Defense Nuclear Facility is terminated (except for a termination for cause) applies to management and... requirements set forth in subpart 926.71, Implementation of Section 3161 of the National Defense Authorization...

  13. 48 CFR 970.2672-2 - Requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Defense Nuclear Facility is terminated (except for a termination for cause) applies to management and... requirements set forth in subpart 926.71, Implementation of Section 3161 of the National Defense Authorization...

  14. Planetary Defense: Are we currently looking for our keys under the lamp post?

    NASA Astrophysics Data System (ADS)

    Nuth, J. A., III; Barbee, B.; Leung, R. Y.

    2016-12-01

    Planetary Defense is a serious and important endeavor and the approach taken to date is a sensible beginning. Finding and cataloging all potentially hazardous asteroids and supporting research into relevant topics required to divert such a threat to our home planet is a necessary, but far from sufficient set of activities required to ensure the survival of our species. Concentrating our efforts on the asteroid threat is relatively easy. Most asteroids move in near-circular orbits, are relatively close to the ecliptic plane and are likely to be detected as hazards many decades in advance of a potential impact. The single most likely problem that will be encountered in deflecting such a threat will be developing the political will to fund the project while there is still ample time for multiple deflection techniques to be applied successfully. While asteroid threats can be mitigated, comets are the invisible danger lurking in the vast, dark parking lot that is the outer solar system. Very few comets falling into the inner solar system will be detected more than two years before their arrival: refinement of a new comet's trajectory requires months of observation before its hazard potential can be realistically assessed and knowledge of the composition, mass and shape of the body cannot be refined sufficiently to design a deflection campaign without much more observational effort. To make matters worse, because of the highly elliptical orbits of most new comets, some of which can be far out of the ecliptic plane while a few can even be in retrograde orbits, the impact velocity of a typical comet will be significantly higher than that of an asteroid. If this increase is only a factor of two, then a typical comet carries four times the impact energy of an asteroid of similar size, though much higher multipliers are possible. The distribution of meteor stream velocities can be examined to place bounds on this threat. Finally, the time required to assemble and launch an asteroid deflection mission starting from scratch and with a high probability of success could exceed three years from mission approval. Based on the recent passage of Comet Siding Spring one must therefore conclude that a successful comet deflection mission must begin well before a hazardous comet is even detected, much less characterized as a significant threat.

  15. 48 CFR 970.2672-2 - Requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Defense Nuclear Facility is terminated (except for a termination for cause) applies to management and... requirements set forth in 48 CFR 926.71, Implementation of Section 3161 of the National Defense Authorization...

  16. Hydrocode Models of Mitigation of a 170-Meter-Diameter Asteroid Using Energetic Techniques

    NASA Astrophysics Data System (ADS)

    Plesko, C. S.; Gisler, G. R.; Heberling, T.; Nouanesengsy, B.; Patchett, J.; Sagert, I.; Tarnowsky, T. J.; Weaver, R.

    2017-12-01

    Binary asteroid 65803 Didymos is the target of the proposed NASA Double Asteroid Redirection Test (DART) mission. The smaller member of the binary pair, S/2003 (65803) Didymos B, is approximately 170 meters in diameter. Didymos A is spectrally similar to H-LL ordinary chondrites and asteroids Eros and Itokawa, so we assume Didymos B is similar. We also assume it to be a rubble pile aggregate of material from Didymos A, and take further guidance on material properties from the AIM Didymos Reference Model V. 10 (P. Michel et al., 2015). We are modeling deflection attempts by kinetic impactor and nuclear stand-off burst against a hypothetical solo Didymos B asteroid as part of the NASA-NNSA inter-agency collaboration on impact hazard mitigation. The collaboration agreed on model initial conditions at our February 2017 Technical Interchange Meeting. The kinetic impactor is a 63.5 cm-diameter aluminum impactor striking at 10 km/s. We model the stand-off nuclear burst according to procedures described in Barbee et al. (Acta A. 2017) and Dearborn et al. (in press). We will present our model predictions and their implications for planetary defense mission design space.

  17. The Asteroid Redirect Mission (ARM): Exploration of a Former Binary NEA?

    NASA Technical Reports Server (NTRS)

    Abell, P. A.; Mazanek, D. D.; Reeves, D. M.; Chodas, P. W.; Gates, M. M.; Johnson, L. N.; Ticker, R. L.

    2016-01-01

    The National Aeronautics and Space Administration (NASA) is developing the Asteroid Redirect Mission (ARM) as a capability demonstration for future human exploration, including use of high-power solar electric propulsion, which allows for the efficient movement of large masses through deep space. The ARM will also demonstrate the capability to conduct proximity operations with natural space objects and crewed operations beyond the security of quick Earth return. The Asteroid Redirect Robotic Mission (ARRM), currently in formulation, will visit a large near-Earth asteroid (NEA), collect a multi-ton boulder from its surface, conduct a demonstration of a slow push planetary defense technique, and redirect the multi-ton boulder into a stable orbit around the Moon. Once returned to cislunar space in the mid-2020s, astronauts aboard an Orion spacecraft will dock with the robotic vehicle to explore the boulder and return samples to Earth. The ARM is part of NASA's plan to advance technologies, capabilities, and spaceflight experience needed for a human mission to the Martian system in the 2030s. The ARM and subsequent availability of the asteroidal material in cis-lunar space, provide significant opportunities to advance our knowledge of small bodies in the synergistic areas of science, planetary defense, and in-situ resource utilization (ISRU). The current reference target for the ARM is NEA (341843) 2008 EV5, which may have been the primary body of a former binary system (Busch et al., 2011; Tardivel et al., 2016). The ARRM will perform several close proximity operations to investigate the NEA and map its surface. A detailed investigation of this object may allow a better understanding of binary NEA physical characteristics and the possible outcomes for their evolution. An overview of the ARM robotic and crewed segments, including mission operations, and a discussion of potential opportunities for participation with the ARM will be provided in this presentation.

  18. The Asteroid Redirect Mission (ARM)

    NASA Astrophysics Data System (ADS)

    Abell, Paul; Gates, Michele; Johnson, Lindley; Chodas, Paul; Mazanek, Dan; Reeves, David; Ticker, Ronald

    2016-07-01

    To achieve its long-term goal of sending humans to Mars, the National Aeronautics and Space Administration (NASA) plans to proceed in a series of incrementally more complex human spaceflight missions. Today, human flight experience extends only to Low-Earth Orbit (LEO), and should problems arise during a mission, the crew can return to Earth in a matter of minutes to hours. The next logical step for human spaceflight is to gain flight experience in the vicinity of the Moon. These cis-lunar missions provide a "proving ground" for the testing of systems and operations while still accommodating an emergency return path to the Earth that would last only several days. Cis-lunar mission experience will be essential for more ambitious human missions beyond the Earth-Moon system, which will require weeks, months, or even years of transit time. In addition, NASA has been given a Grand Challenge to find all asteroid threats to human populations and know what to do about them. Obtaining knowledge of asteroid physical properties combined with performing technology demonstrations for planetary defense provide much needed information to address the issue of future asteroid impacts on Earth. Hence the combined objectives of human exploration and planetary defense give a rationale for the Asteroid Re-direct Mission (ARM). Mission Description: NASA's ARM consists of two mission segments: 1) the Asteroid Redirect Robotic Mission (ARRM), the first robotic mission to visit a large (greater than ~100 m diameter) near-Earth asteroid (NEA), collect a multi-ton boulder from its surface along with regolith samples, demonstrate a planetary defense technique, and return the asteroidal material to a stable orbit around the Moon; and 2) the Asteroid Redirect Crewed Mission (ARCM), in which astronauts will take the Orion capsule to rendezvous and dock with the robotic vehicle, conduct multiple extravehicular activities to explore the boulder, and return to Earth with samples. NASA's proposed ARM concept would leverage several key ongoing activities in human exploration, space technology, and planetary defense. The ARRM is planned to launch at the end of 2021 and the ARCM is scheduled for late 2026. Mission Objectives: The Asteroid Redirect Mission is designed to address the need for flight experience in cis-lunar space and provide opportunities for testing the systems, technologies, and capabilities that will be required for future human operations in deep space. A principle objective of the ARM is the development of a high-power Solar Electric Propulsion (SEP) vehicle, and the demonstration that it can operate for many years in interplanetary space, which is critical for deep-space exploration missions. A second prime objective of ARM is to conduct a human spaceflight mission involving in-space inter-action with a natural object, in order to provide the systems and operational experience that will be required for eventual human exploration of the Mars system, including the moons Phobos and Deimos. The ARCM provides a focus for the early flights of the Orion program. Astronauts will participate in the scientific in-space investigation of nearly pristine asteroid material, at most only minimally altered by the capture process. The ARCM will provide the opportunity for human explorers to work in space with asteroid material, testing the activities that would be performed and tools that would be needed for later exploration of primitive body surfaces in deep space. The operational experience would be gained close to our home planet, making it a significantly more affordable approach to obtaining this experience. Target Asteroid Candidates: NASA has identified the NEA (341843) 2008 EV5 as the reference target for the ARRM, but is also carrying three other NEAs as potential options [(25143) Itokawa, (162173) Ryugu, and (101955) Bennu]. NASA is continuing to search for additional candidate asteroid targets for ARM. The final target selection for the ARRM will be made approximately a year before launch, but there is a strong recommendation from the scientific and resource utilization communities that the ARM target be volatile and organic rich. Three of the proposed candidates are carbonaceous NEAs. Specifically, the ARRM reference target, 2008 EV5 is a carbonaceous (C-type) asteroid that has been remotely characterized (via visual, infrared, and radar wavelengths), is believed to be hydrated, and provides significant return mass (boulders on the surface greater than 20 metric tons). It also has an advantage in that the orbital dynamics of the NEA fall within the current baseline mission timeline of five years between the return of the robotic vehicle to cis-lunar space and the launch of the ARCM. Therefore, NEA 2008 EV5 provides a valid target that can be used to help with formulation and development efforts. Input to ARM and Future Activities: In the fall of 2015, NASA chartered the Formulation Assessment and Support Team (FAST) to provide timely inputs for mission requirement formulation in support of the ARRM Requirements Closure Technical Interchange Meeting (TIM) in mid-December of 2015, to assist in developing an initial list of potential mission investigations, and to provide input on potential hosted payloads and partnerships. Expertise from the science, engineering, and technology communities was represented in exploring lines of inquiry related to key characteristics of the ARRM reference target asteroid (2008 EV5) for engineering design purposes. As of December 2015, the FAST has been formally retired and the FAST final report was publically released in February of 2016. However, plans have been made to stand up an ARM Investigation Team (IT), which is expected be formed in 2016. The multidisciplinary IT will assist with the definition and support of mission investigations, support ARM program-level and project-level functions, and support NASA Head-quarters interactions with the science and technology communities through mission formulation, mission design and vehicle development, and mission implementation.

  19. Asteroid Detection Results Using the Space Surveillance Telescope

    NASA Astrophysics Data System (ADS)

    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.

  20. Asteroid Detection Results Using the Space Surveillance Telescope

    NASA Astrophysics Data System (ADS)

    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.

  1. Comparison of Damage from Hydrocode Simulations of an Asteroid Airburst or Impact on Land, in Deep, or in Shallow Water

    NASA Technical Reports Server (NTRS)

    Robertson, Darrel; Wheeler, Lorien; Mathias, Donovan

    2017-01-01

    If an asteroid is discovered to be on a collision course with Earth and there is insufficient time for a deflection effort to make it miss Earth completely, should it be redirected to a land or ocean impact? While distance from densely populated areas should obviously be maximized, the differing ability of air blast, seismic waves, and tsunami waves to cause damage at distance does not make the choice between land and ocean impacts an immediately obvious one. More broadly this work is a step towards improving damage models from asteroid impacts. This extended abstract follows the hypothetical scenario of the 2017 IAA Planetary Defense Conference where a 100-250m diameter asteroid is on a potential impact course with Earth. A hydrocode was used to simulate impacts into the most sparsely populated areas along the eastern end of the hypothetical impact corridor- specifically in the Gobi Desert, in the shallow waters of the Sea of Japan, and in the deep waters of the Japan Trench in the Pacific Ocean.

  2. 3-Dimensional Reconstruction of the ROSETTA Targets - Application to Asteroid 2867 Steins

    NASA Astrophysics Data System (ADS)

    Besse, Sebastien; Groussin, O.; Jorda, L.; Lamy, P.; OSIRIS Team

    2008-09-01

    The OSIRIS imaging experiment aboard the Rosetta spacecraft will image asteroids Steins in September 2008 and Lutetia in 2010, and comet 67P/Churyumov-Gerasimenko in 2014. An accurate determination of the shape is a key point for the success of the mission operations and scientific objectives. Based on the experience of previous space missions (Deep Impact, Near, Galileo, Hayabusa), we are developing our own procedure for the shape reconstruction of small bodies. We use two different techniques : i) limb and terminator constraints and ii) ground control points (GCP) constraints. The first method allows the determination of a rough shape of the body when it is poorly resolved and no features are visible on the surface, while the second method provides an accurate shape model using high resolution images. We are currently testing both methods on simulated data, using and developing different algorithms for limb and terminator extraction (e.g.,wavelet), detection of points of interest (Harris, Susan, Fast Corner Detection), points pairing using correlation techniques (geometric model) and 3-dimensional reconstruction using line-of-sight information (photogrammetry). Both methods will be fully automated. We will hopefully present the 3D reconstruction of the Steins asteroid from images obtained during its flyby. Acknowledgment: Sébastien Besse acknowledges CNES and Thales for funding.

  3. Human Exploration of Near-Earth Asteroids

    NASA Technical Reports Server (NTRS)

    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.

  4. NASA's asteroid redirect mission: Robotic boulder capture option

    NASA Astrophysics Data System (ADS)

    Abell, P.; Nuth, J.; Mazanek, D.; Merrill, R.; Reeves, D.; Naasz, B.

    2014-07-01

    NASA is examining two options for the Asteroid Redirect Mission (ARM), which will return asteroid material to a Lunar Distant Retrograde Orbit (LDRO) using a robotic solar-electric-propulsion spacecraft, called the Asteroid Redirect Vehicle (ARV). Once the ARV places the asteroid material into the LDRO, a piloted mission will rendezvous and dock with the ARV. After docking, astronauts will conduct two extravehicular activities (EVAs) to inspect and sample the asteroid material before returning to Earth. One option involves capturing an entire small (˜4--10 m diameter) near-Earth asteroid (NEA) inside a large inflatable bag. However, NASA is also examining another option that entails retrieving a boulder (˜1--5 m) via robotic manipulators from the surface of a larger (˜100+ m) pre-characterized NEA. The Robotic Boulder Capture (RBC) option can leverage robotic mission data to help ensure success by targeting previously (or soon to be) well-characterized NEAs. For example, the data from the Japan Aerospace Exploration Agency's (JAXA) Hayabusa mission has been utilized to develop detailed mission designs that assess options and risks associated with proximity and surface operations. Hayabusa's target NEA, Itokawa, has been identified as a valid target and is known to possess hundreds of appropriately sized boulders on its surface. Further robotic characterization of additional NEAs (e.g., Bennu and 1999 JU_3) by NASA's OSIRIS REx and JAXA's Hayabusa 2 missions is planned to begin in 2018. This ARM option reduces mission risk and provides increased benefits for science, human exploration, resource utilization, and planetary defense.

  5. Asteroid Return Mission Feasibility Study

    NASA Technical Reports Server (NTRS)

    Brophy, John R.; Gershman, Robert; Landau, Damon; Polk, James; Porter, Chris; Yeomans, Don; Allen, Carlton; Williams, Willie; Asphaug, Erik

    2011-01-01

    This paper describes an investigation into the technological feasibility of finding, characterizing, robotically capturing, and returning an entire Near-Earth Asteroid (NEA) to the International Space Station (ISS) for scientific investigation, evaluation of its resource potential, determination of its internal structure and other aspects important for planetary defense activities, and to serve as a testbed for human operations in the vicinity of an asteroid. Reasonable projections suggest that several dozen candidates NEAs in the size range of interest (approximately 2-m diameter) will be known before the end of the decade from which a suitable target could be selected. The conceptual mission objective is to return an approximately 10,000-kg asteroid to the ISS in a total flight time of approximately 5 years using a single Evolved Expendable Launch Vehicle. Preliminary calculations indicate that this could be accomplished using a solar electric propulsion (SEP) system with high-power Hall thrusters and a maximum power into the propulsion system of approximately 40 kW. The SEP system would be used to provide all of the post-launch delta V. The asteroid would have an unrestricted Earth return Planetary Protection categorization, and would be curated at the ISS where numerous scientific and resource utilization experiments would be conducted. Asteroid material brought to the ground would be curated at the NASA Johnson Space Center. This preliminary study identified several areas where additional work is required, but no show stoppers were identified for the approach that would return an entire 10,000-kg asteroid to the ISS in a mission that could be launched by the end of this decade.

  6. Asteroid Redirect Robotic Mission: Robotic Boulder Capture Option Overview

    NASA Technical Reports Server (NTRS)

    Mazanek, Daniel D.; Merrill, Raymond G.; Belbin, Scott P.; Reeves, David M.; Earle, Kevin D.; Naasz, Bo J.; Abell, Paul A.

    2014-01-01

    The National Aeronautics and Space Administration (NASA) is currently studying an option for the Asteroid Redirect Robotic Mission (ARRM) that would capture a multi-ton boulder (typically 2-4 meters in size) from the surface of a large (is approximately 100+ meter) Near-Earth Asteroid (NEA) and return it to cislunar space for subsequent human and robotic exploration. This alternative mission approach, designated the Robotic Boulder Capture Option (Option B), has been investigated to determine the mission feasibility and identify potential differences from the initial ARRM concept of capturing an entire small NEA (4-10 meters in size), which has been designated the Small Asteroid Capture Option (Option A). Compared to the initial ARRM concept, Option B allows for centimeter-level characterization over an entire large NEA, the certainty of target NEA composition type, the ability to select the boulder that is captured, numerous opportunities for mission enhancements to support science objectives, additional experience operating at a low-gravity planetary body including extended surface contact, and the ability to demonstrate future planetary defense strategies on a hazardous-size NEA. Option B can leverage precursor missions and existing Agency capabilities to help ensure mission success by targeting wellcharacterized asteroids and can accommodate uncertain programmatic schedules by tailoring the return mass.

  7. Asteroid Redirect Mission (ARM) Formulation Assessment and Support Team (FAST) Final Report

    NASA Technical Reports Server (NTRS)

    Mazanek, Daniel D.; Reeves, David M.; Abell, Paul A.; Asphaug, Erik; Abreu, Neyda M.; Bell, James F.; Bottke, William F.; Britt, Daniel T.; Campins, Humberto; Chodas, Paul W.; hide

    2016-01-01

    The Asteroid Redirect Mission (ARM) Formulation Assessment and Support Team (FAST) was a two-month effort, chartered by NASA, to provide timely inputs for mission requirement formulation in support of the Asteroid Redirect Robotic Mission (ARRM) Requirements Closure Technical Interchange Meeting held December 15-16, 2015, to assist in developing an initial list of potential mission investigations, and to provide input on potential hosted payloads and partnerships. The FAST explored several aspects of potential science benefits and knowledge gain from the ARM. Expertise from the science, engineering, and technology communities was represented in exploring lines of inquiry related to key characteristics of the ARRM reference target asteroid (2008 EV5) for engineering design purposes. Specific areas of interest included target origin, spatial distribution and size of boulders, surface geotechnical properties, boulder physical properties, and considerations for boulder handling, crew safety, and containment. In order to increase knowledge gain potential from the mission, opportunities for partnerships and accompanying payloads were also investigated. Potential investigations could be conducted to reduce mission risks and increase knowledge return in the areas of science, planetary defense, asteroid resources and in-situ resource utilization, and capability and technology demonstrations. This report represents the FASTâ€"TM"s final product for the ARM.

  8. Using Information from Rendezvous Missions For Best-Case Appraisals of Impact Damage to Planet Earth Caused By Natural Objects

    NASA Technical Reports Server (NTRS)

    Arnold, J. O.; Chodas, P. W.; Ulamec, S.; Mathias, D. L.; Burkhard, C. D.

    2017-01-01

    The Asteroid Threat Assessment Project (ATAP), a part of NASAs Planetary Defense Coordination Office (PDCO) has the responsibility to appraise the range of surface damage by potential asteroid impacts on land or water. If a threat is realized, the project will provide appraisals to officials empowered to make decisions on potential mitigation actions. This paper describes a scenario for assessment of surface damage when characterization of an asteroid had been accomplished by a rendezvous mission that would be conducted by the international planetary defense community. It is shown that the combination of data from ground and in-situ measurements on an asteroid provides knowledge that can be used to pin-point its impact location and predict the level of devastation it would cause. The hypothetical asteroid 2017 PDC with a size of 160 to 290 m in diameter to be discussed at the PDC 2017 meeting is used as an example. In order of importance for appraising potential damage, information required is: (1) where will the surface impact occur? (2) What is the mass, shape and size of the asteroid and what is its entry state (speed and entry angle) at the 100 km atmospheric pierce point? And (3) is the asteroid a monolith or a rubble pile? If it is a rubble pile, what is its sub and interior structure? Item (1) is of first order importance to determine levels of devastation (loss of life and infrastructure damage) because it varies strongly on the impact location. Items (2) and (3) are used as input for ATAPs simulations to define the level of surface hazards: winds, overpressure, thermal exposure; all created by the deposition of energy during the objects atmospheric flight, andor cratering. Topics presented in this paper include: (i) The devastation predicted by 2017 PDCs impact based on initial observations using ATAPs risk assessment capability, (ii) How information corresponding to items (1) to (3) could be obtained from a rendezvous mission, and (iii) How information from a rendezvous mission could be used, along with that from ground observations and data from the literature, could provide input for an new risk analysis capability that is emerging from ATAPs research. It is concluded that this approach would result in appraisal with the least uncertainty possible (herein called the best-case) using simulation capabilities that are currently available or will be in the future.

  9. Using Information from Rendezvous Missions For Best-Case Appraisals of Impact Damage to Planet Earth Caused By Natural Objects

    NASA Technical Reports Server (NTRS)

    Arnold, James O.; Chodas, Paul W.; Ulamec, Stephan; Mathias, Donovan L.; Burkhard, Craig D.

    2017-01-01

    The Asteroid Threat Assessment Project (ATAP), a part of NASAs Planetary Defense Coordination Office (PDCO) has the responsibility to appraise the range of surface damage by potential asteroid impacts on land or water. If a threat is realized, the project will provide appraisals to officials empowered to make decisions on potential mitigation actions. This paper describes a scenario for assessment of surface damage when characterization of an asteroid had been accomplished by a rendezvous mission that would be conducted by the international planetary defense community. It is shown that the combination of data from ground and in-situ measurements on an asteroid provides knowledge that can be used to pin-point its impact location and predict the level of devastation it would cause. The hypothetical asteroid 2017 PDC with a size of 160 to 290 m in diameter to be discussed at the PDC 2017 meeting is used as an example. In order of importance for appraising potential damage, information required is: (1) where will the surface impact occur? (2) What is the mass, shape and size of the asteroid and what is its entry state (speed and entry angle) at the 100 km atmospheric pierce point? And (3) is the asteroid a monolith or a rubble pile? If it is a rubble pile, what is its sub and interior structure? Item (1) is of first order importance to determine levels of devastation (loss of life and infrastructure damage) because it varies strongly on the impact location. Items (2) and (3) are used as input for ATAPs simulations to define the level of surface hazards: winds, overpressure, thermal exposure; all created by the deposition of energy during the objects atmospheric flight, and/or cratering. Topics presented in this paper include: (i) The devastation predicted by 2017 PDCs impact based on initial observations using ATAPs risk assessment capability, (ii) How information corresponding to items (1) to (3) could be obtained from a rendezvous mission, and (iii) How information from a rendezvous mission could be used, along with that from ground observations and data from the literature, could provide input for an new risk analysis capability that is emerging from ATAPs research. It is concluded that this approach would result in appraisal with the least uncertainty possible (herein called the best-case) using simulation capabilities that are currently available or will be in the future.

  10. Using Information from Rendezvous Missions for Best-Case Appraisals of Impact Damage to Planet Earth Caused by Natural Objects

    NASA Technical Reports Server (NTRS)

    Arnold, James O.; Chodas, Paul W.; Ulamec, Stephan; Mathias, Donovan L.; Burkhard, Craig D.

    2017-01-01

    The Asteroid Threat Assessment Project (ATAP), a part of NASAs Planetary Defense Coordination Office (PDCO) has the responsibility to appraise the range of surface damage by potential asteroid impacts on land or water. If a threat is realized, the project will provide appraisals to officials empowered to make decisions about potential mitigation actions. This paper describes a scenario for assessment of surface damage when characterization of an asteroid had been accomplished by a rendezvous mission that would be conducted by the international planetary defense community. It is shown that the combination of data from ground and in-situ measurements on an asteroid provides knowledge that can be used to pin-point its impact location and predict the level of devastation it would cause. The hypothetical asteroid 2017 PDC with a size range of 160 to 290 m in diameter to be discussed at the PDC 2017 is used as an example. In order of importance for appraising potential damage, information required is: (1) where will the surface impact occur? (2) what is the mass, shape and size of the asteroid and what is its entry state (speed and entry angle) at the 100 km atmospheric pierce point? And (3) is the asteroid a monolith or a rubble pile? If it is a rubble pile, what is its structure and heterogeneity from the surface and throughout its interior? Item (1) is of first order importance to determine levels of devastation (loss of life and infrastructure damage) because it varies strongly on the impact location. Items (2) and (3) are used as inputs for ATAPs simulations to define the level of surface hazards: winds, overpressure, thermal exposure; all created by the deposition of energy during the objects atmospheric flight, andor cratering. Topics presented in this paper include: (i) the devastation predicted by 2017 PDCs impact on land based on initial observations using ATAPs risk assessment capability, (ii) how information corresponding to items (1) to (3) could be obtained from a rendezvous mission, and (iii) how information from a rendezvous mission could be used, along with that from ground observations and data from the literature to provide input for a new risk analysis capability that is emerging from ATAPs research. It is concluded that this approach would result in the creation of an appraisal of the threat from 2017 PDC with the least uncertainty possible, herein called the best-case.

  11. Near Earth Asteroid Characterization for Threat Assessment

    NASA Technical Reports Server (NTRS)

    Dotson, Jessie; Mathias, Donovan; Wheeler, Lorien; Wooden, Diane; Bryson, Kathryn; Ostrowski, Daniel

    2017-01-01

    Physical characteristics of NEAs are an essential input to modeling behavior during atmospheric entry and to assess the risk of impact but determining these properties requires a non-trivial investment of time and resources. The characteristics relevant to these models include size, density, strength and ablation coefficient. Some of these characteristics cannot be directly measured, but rather must be inferred from related measurements of asteroids and/or meteorites. Furthermore, for the majority of NEAs, only the basic measurements exist so often properties must be inferred from statistics of the population of more completely characterized objects. The Asteroid Threat Assessment Project at NASA Ames Research Center has developed a probabilistic asteroid impact risk (PAIR) model in order to assess the risk of asteroid impact. Our PAIR model and its use to develop probability distributions of impact risk are discussed in other contributions to PDC 2017 (e.g., Mathias et al.). Here we utilize PAIR to investigate which NEA characteristics are important for assessing the impact threat by investigating how changes in these characteristics alter the damage predicted by PAIR. We will also provide an assessment of the current state of knowledge of the NEA characteristics of importance for asteroid threat assessment. The relative importance of different properties as identified using PAIR will be combined with our assessment of the current state of knowledge to identify potential high impact investigations. In addition, we will discuss an ongoing effort to collate the existing measurements of NEA properties of interest to the planetary defense community into a readily accessible database.

  12. A Clementine collection: Moonglow

    NASA Astrophysics Data System (ADS)

    1994-06-01

    The Clementine story began in 1990 when NASA administrator Richard Truly asked the Department of Defense to consider a joint NASA/DOD mission that would achieve goals mutually beneficial to both organizations. That request was given to the then Strategic Defense Initiative Organization (SDIO) to investigate. A mission was conceived to test the latest in space-based imaging components, using the moon and a near-earth asteroid as celestial targets. The Clementine mission is the result of those early investigations. This collection is an early sampling of the 1.8 million images acquired by the Clementine spacecraft.

  13. 78 FR 16476 - Notice for Termination of a Disease Management Demonstration Project for TRICARE Standard...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-15

    ... Management Demonstration Project for TRICARE Standard Beneficiaries.'' The demonstration provided disease... DEPARTMENT OF DEFENSE Office of the Secretary Notice for Termination of a Disease Management Demonstration Project for TRICARE Standard Beneficiaries AGENCY: Office of the Secretary of Defense, (Health...

  14. NASA's Asteroid Redirect Mission: A Robotic Boulder Capture Option for Science, Human Exploration, Resource Utilization, and Planetary Defense

    NASA Technical Reports Server (NTRS)

    Abell, P.; Nuth, J.; Mazanek, D.; Merrill, R.; Reeves, D.; Naasz, B.

    2014-01-01

    NASA is examining two options for the Asteroid Redirect Mission (ARM), which will return asteroid material to a Lunar Distant Retrograde Orbit (LDRO) using a robotic solar electric propulsion spacecraft, called the Asteroid Redirect Vehicle (ARV). Once the ARV places the asteroid material into the LDRO, a piloted mission will rendezvous and dock with the ARV. After docking, astronauts will conduct two extravehicular activities (EVAs) to inspect and sample the asteroid material before returning to Earth. One option involves capturing an entire small (4 - 10 m diameter) near-Earth asteroid (NEA) inside a large inflatable bag. However, NASA is also examining another option that entails retrieving a boulder (1 - 5 m) via robotic manipulators from the surface of a larger (100+ m) pre-characterized NEA. The Robotic Boulder Capture (RBC) option can leverage robotic mission data to help ensure success by targeting previously (or soon to be) well- characterized NEAs. For example, the data from the Japan Aerospace Exploration Agency's (JAXA) Hayabusa mission has been utilized to develop detailed mission designs that assess options and risks associated with proximity and surface operations. Hayabusa's target NEA, Itokawa, has been identified as a valid target and is known to possess hundreds of appropriately sized boulders on its surface. Further robotic characterization of additional NEAs (e.g., Bennu and 1999 JU3) by NASA's OSIRIS REx and JAXA's Hayabusa 2 missions is planned to begin in 2018. This ARM option reduces mission risk and provides increased benefits for science, human exploration, resource utilization, and planetary defense. Science: The RBC option is an extremely large sample-return mission with the prospect of bringing back many tons of well-characterized asteroid material to the Earth-Moon system. The candidate boulder from the target NEA can be selected based on inputs from the world-wide science community, ensuring that the most scientifically interesting boulder be returned for subsequent sampling. In addition, the material surrounding the boulder can be collected from the surface, thus providing geological contextual information and additional samples of NEA regolith. The robotic manipulators used for capturing the boulder will ensure some of the surface remains undisturbed and that the boulder will retain its structural integrity, which will preserve the context of any samples collected by the astronauts and ensure a high level of science return. Human Exploration: Due to the coherent nature of the boulder that will be collected, entire encapsulation of the asteroid material is not required. This facilitates exploration and sample collection of the boulder by astronauts in a variety of ways. The total time for EVA during the crew portion of the mission is very limited. Current estimates are that each of the two EVAs will only last four hours. The RBC option will allow crew members to have good situational awareness of the work site and quickly identify sample sites of interest. In addition, the samples to be collected can be readily accessed without having to deal with removal of an encapsulation system, which adds extra complexity and risk for the astronauts during EVA. Resource Utilization: One of the most crucial aspects for resource utilization is the identification and collection of appropriate materials (e.g., volatiles, organics, metals, etc.) that contain components of interest. Prior characterization of NEAs is required in order to increase the likelihood that appropriate materials will be returned. Ground-based observations of small (<10 m) NEAs are challenging, but characterization efforts of larger targets have demonstrated that NEAs with volatiles and organics have been identified. Two potential targets for the RBC option (Bennu and 1999 JU3) have been previously identified as potentially rich in resources, and both are already targets of currently planned robotic missions that will characterize their physical properties in great detail. Planetary Defense: The RBC option involves interaction with a well- characterized potentially hazardoussized NEA that would enable NASA to conduct one or more planetary defense demonstrations. The primary method would use the collected boulder to augment the mass of the ARV and perform an Enhanced Gravity Tractor (EGT) demonstration on the NEA. Additionally, other approaches could be demonstrated during the mission, such as Ion Beam Deflection (IBD) and/or observation of a Kinetic Impactor (KI). The relative effectiveness of a slow push-pull method such as the EGT or IBD could be directly compared and contrasted with the results of the more energetic KI method on the target NEA. Conclusions: This boulder option for NASA's ARM can leverage knowledge of previously characterized NEAs from prior robotic missions, which provides more certainty of the target NEA's physical characteristics and reduces mission risk. This increases the return on investment for NASA's future activities with respect to human exploration, resource utilization, and planetary defense.

  15. On the Astrid asteroid family

    NASA Astrophysics Data System (ADS)

    Carruba, V.

    2016-09-01

    Among asteroid families, the Astrid family is peculiar because of its unusual inclination distribution. Objects at a ≃ 2.764 au are quite dispersed in this orbital element, giving the family a `crab-like' appearance. Recent works showed that this feature is caused by the interaction of the family with the s - sC nodal secular resonance with Ceres, that spreads the inclination of asteroids near its separatrix. As a consequence, the currently observed distribution of the vW component of terminal ejection velocities obtained from inverting Gauss equation is quite leptokurtic, since this parameter mostly depends on the asteroids inclination. The peculiar orbital configuration of the Astrid family can be used to set constraints on key parameters describing the strength of the Yarkovsky force, such as the bulk and surface density and the thermal conductivity of surface material. By simulating various fictitious families with different values of these parameters, and by demanding that the current value of the kurtosis of the distribution in vW be reached over the estimated lifetime of the family, we obtained that the thermal conductivity of Astrid family members should be ≃0.001 W m-1 K-1, and that the surface and bulk density should be higher than 1000 kg m-3. Monte Carlo methods simulating Yarkovsky and stochastic Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) evolution of the Astrid family show its age to be T = 140 ± 30 Myr old, in good agreement with estimates from other groups. Its terminal ejection velocity parameter is in the range V_{EJ}= 5^{+17}_{-5} m s-1. Values of VEJ larger than 25 m s-1 are excluded from constraints from the current inclination distribution.

  16. Seismo-Acoustic Numerical Investigation of Land Impacts, Water Impacts, or Air Bursts of Asteroids

    NASA Astrophysics Data System (ADS)

    Ezzedine, S. M.; Miller, P. L.; Dearborn, D. S.

    2016-12-01

    The annual probability of an asteroid impact is low, but over time, such catastrophic events are inevitable. Interest in assessing the impact consequences has led us to develop a physics-based framework to seamlessly simulate the event from entry to impact, including air, water and ground shock propagation and wave generation. The non-linear effects are simulated using the hydrodynamics code GEODYN. As effects propagate outward, they become a wave source for the linear-elastic-wave propagation code and simulated using SAW or SWWP, depends on whether the asteroid impacts the land or the ocean, respectively. The GEODYN-SAW-SWWP coupling is based on the structured adaptive-mesh-refinement infrastructure, SAMRAI, and has been used in FEMA table-top exercises conducted in 2013 and 2014, and more recently, the 2015 Planetary Defense Conference exercise. Moreover, during atmospheric entry, asteroids create an acoustic trace that could be used to infer several physical characteristics of asteroid itself. Using SAW we explore the physical space parameters in order to rank the most important characteristics; Results from these simulations provide an estimate of onshore and offshore effects and can inform more sophisticated inundation and structural models. The capabilities of this methodology are illustrated by providing results for different impact locations, and an exploration of asteroid size on the waves arriving at the shoreline of area cities. We constructed the maximum and minimum envelops of water-wave heights or acceleration spectra given the size of the asteroid and the location of the impact along the risk corridor. Such profiles can inform emergency response and disaster-mitigation efforts. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  17. Seismo-Acoustic Numerical Investigation of Land Impacts, Water Impacts, or Air Bursts of Asteroids

    NASA Astrophysics Data System (ADS)

    Ezzedine, S. M.; Dearborn, D. S.; Miller, P. L.

    2017-12-01

    The annual probability of an asteroid impact is low, but over time, such catastrophic events are inevitable. Interest in assessing the impact consequences has led us to develop a physics-based framework to seamlessly simulate the event from entry to impact, including air, water and ground shock propagation and wave generation. The non-linear effects are simulated using the hydrodynamics code GEODYN. As effects propagate outward, they become a wave source for the linear-elastic-wave propagation code and simulated using SAW or SWWP, depends on whether the asteroid impacts the land or the ocean, respectively. The GEODYN-SAW-SWWP coupling is based on the structured adaptive-mesh-refinement infrastructure, SAMRAI, and has been used in FEMA table-top exercises conducted in 2013 and 2014, and more recently, the 2015 Planetary Defense Conference exercise. Moreover, during atmospheric entry, asteroids create an acoustic trace that could be used to infer several physical characteristics of asteroid itself. Using SAW we explore the physical space parameters in order to rank the most important characteristics; Results from these simulations provide an estimate of onshore and offshore effects and can inform more sophisticated inundation and structural models. The capabilities of this methodology are illustrated by providing results for different impact locations, and an exploration of asteroid size on the waves arriving at the shoreline of area cities. We constructed the maximum and minimum envelops of water-wave heights or acceleration spectra given the size of the asteroid and the location of the impact along the risk corridor. Such profiles can inform emergency response and disaster-mitigation efforts. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  18. Discovery of Spin-Rate-Dependent Asteroid Thermal Inertia

    NASA Astrophysics Data System (ADS)

    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.

  19. 75 FR 11136 - Federal Advisory Committee; U.S. Nuclear Command and Control System Comprehensive Review...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-10

    ... DEPARTMENT OF DEFENSE Office of the Secretary Federal Advisory Committee; U.S. Nuclear Command and Control System Comprehensive Review Committee; Charter Termination AGENCY: Department of Defense (DoD... terminating the charter for the U.S. Nuclear Command and Control System Comprehensive Review Committee. FOR...

  20. The Main-belt Asteroid and NEO Tour with Imaging and Spectroscopy (MANTIS)

    NASA Astrophysics Data System (ADS)

    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.

  1. Education and Outreach for Volunteer Planetary Defense

    NASA Astrophysics Data System (ADS)

    Burke, J. D.

    2016-12-01

    When a large meteor exploded over Chelyabinsk in 2013, people saw the bright flash and rushed to windows. Then the blast wave hit and many were injured by flying glass fragments. Education about airbursts might have reduced the casualties. Education and Public Outreach (EPO) can also be important in broadening public involvement in preparations for dealing with cosmic hazards. Amateur astronomers have an important role in discovering potentially hazardous asteroids and comets, and also in making follow-up observations after discovery. This is especially important for Southern Hemisphere observing sites where professional observers are relatively few. The Planetary Society makes small Shoemaker grants to aid amateur astronomers in this work. Much more could be done if educators, students and the general public were aware of the opportunity and the need. Beyond this, public engagement is essential to raise and maintain support for active agencies, including the UN-sponsored International Asteroid Warning Network (IAWN) and Space Mission Planning Advisory Group (SMPAG). This paper will describe and advocate EPO efforts in support of these and other Volunteer Planetary Defense activities.

  2. Solar electric propulsion for terminal flight to rendezvous with comets and asteroids. [using guidance algorithm

    NASA Technical Reports Server (NTRS)

    Bennett, A.

    1973-01-01

    A guidance algorithm that provides precise rendezvous in the deterministic case while requiring only relative state information is developed. A navigation scheme employing only onboard relative measurements is built around a Kalman filter set in measurement coordinates. The overall guidance and navigation procedure is evaluated in the face of measurement errors by a detailed numerical simulation. Results indicate that onboard guidance and navigation for the terminal phase of rendezvous is possible with reasonable limits on measurement errors.

  3. Comet deflection by directed energy: a finite element analysis

    NASA Astrophysics Data System (ADS)

    Madajian, Jonathan; Griswold, Janelle; Gandra, Anush; Hughes, Gary B.; Zhang, Qicheng; Rupert, Nic; Lubin, Philip

    2016-09-01

    Comets and Asteroids are viable threats to our planet; if these space rocks are smaller than 25 meters, they burn up in the atmosphere, but if they are wider than 25 meters they can cause damage to the impact area. Anything more than one to two kilometers can have worldwide effects, furthermore a mile-wide asteroid travelling at 30,000 miles per hour has the energy equal to a megaton bomb and is very likely to wipe out most of the life on Earth. Residents near Chelyabinsk, Russia experienced the detrimental effects of a collision with a Near-Earth Asteroid (NEA) on 15 February 2013 as a 20 m object penetrated the atmosphere above that city. The effective yield from this object was approximately 1/2 Megaton TNT equivalent (Mt), or that of a large strategic warhead. The 1908 Tunguska event, also over Russia, is estimated to have had a yield of approximately 15 Mt and had the potential to kill millions of people had it come down over a large city1. In the face of such danger a planetary defense system is necessary and this paper proposes a design for such a system. DE-STAR (Directed Energy System for Targeting of Asteroids and exploRation) is a phased array laser system that can be used to oblate, deflect and de-spin asteroids and comets.

  4. NASA's Asteroid Redirect Mission (ARM)

    NASA Astrophysics Data System (ADS)

    Abell, Paul; Mazanek, Dan; Reeves, David; Naasz, Bo; Cichy, Benjamin

    2015-11-01

    The National Aeronautics and Space Administration (NASA) is developing a robotic mission to visit a large near-Earth asteroid (NEA), collect a multi-ton boulder from its surface, and redirect it into a stable orbit around the Moon. Once returned to cislunar space in the mid-2020s, astronauts will explore the boulder and return to Earth with samples. This Asteroid Redirect Mission (ARM) is part of NASA’s plan to advance the technologies, capabilities, and spaceflight experience needed for a human mission to the Martian system in the 2030s. Subsequent human and robotic missions to the asteroidal material would also be facilitated by its return to cislunar space. Although ARM is primarily a capability demonstration mission (i.e., technologies and associated operations), there exist significant opportunities to advance our knowledge of small bodies in the synergistic areas of science, planetary defense, asteroidal resources and in-situ resource utilization (ISRU), and capability and technology demonstrations. In order to maximize the knowledge return from the mission, NASA is organizing an ARM Investigation Team, which is being preceded by the Formulation Assessment and Support Team. These teams will be comprised of scientists, technologists, and other qualified and interested individuals to help plan the implementation and execution of ARM. An overview of robotic and crewed segments of ARM, including the mission requirements, NEA targets, and mission operations, will be provided along with a discussion of the potential opportunities associated with the mission.

  5. The Asteroid Redirect Mission (ARM)

    NASA Technical Reports Server (NTRS)

    Abell, Paul

    2015-01-01

    The National Aeronautics and Space Administration (NASA) is developing a robotic mission to visit a large near-Earth asteroid (NEA), collect a multi-ton boulder from its surface, and redirect it into a stable orbit around the Moon. Once returned to cislunar space in the mid-2020s, astronauts will explore the boulder and return to Earth with samples. This Asteroid Redirect Mission (ARM) is part of NASA's plan to advance the technologies, capabilities, and spaceflight experience needed for a human mission to the Martian system in the 2030s. Subsequent human and robotic missions to the asteroidal material would also be facilitated by its return to cislunar space. Although ARM is primarily a capability demonstration mission (i.e., technologies and associated operations), there exist significant opportunities to advance our knowledge of small bodies in the synergistic areas of science, planetary defense, asteroidal resources and in-situ resource utilization (ISRU), and capability and technology demonstrations. In order to maximize the knowledge return from the mission, NASA is organizing an ARM Investigation Team, which is being preceded by the Formulation Assessment and Support Team. These teams will be comprised of scientists, technologists, and other qualified and interested individuals to help plan the implementation and execution of ARM. An overview of robotic and crewed segments of ARM, including the mission requirements, NEA targets, and mission operations, will be provided along with a discussion of the potential opportunities associated with the mission.

  6. Electrostatic Levitation of Fines on Asteroids

    NASA Astrophysics Data System (ADS)

    Lee, P.

    1995-09-01

    Electrostatic fields can develop at the surface of resistive asteroids exposed directly to solar radiation and to the solar wind. As on the Moon (e.g., [1-3]), the process may lead to the levitation and transport of charged grains, and contribute to winnowing asteroidal regoliths of their finest particle size fraction. Two commonly proposed mechanisms for the levitation of dust on the Moon are applied to asteroids. The first depends on global scale electrostatic fields and involves the development of a near-surface photoelectron layer over the asteroid's sunlit hemisphere [4,5] ; the second involves local fields near the terminator and particle charging by higher-energy photoelectron emission on the sunlit faces of blocks and other small-scale prominences [6,7]. Preliminary modeling results suggest that on a sufficiently resistive and slow-rotating asteroid at a heliocentric distance of 3 AU, the subsolar region evolves surface electrostatic fields of ~5 V/m^-1, while field intensities in the terminator zone may reach ~10^5 V/m^-1. Charged regolithic fines are easily levitated, their fate being a function of their charge and size. On a 20 km-radius chondritic main belt asteroid, particles up to ~100 microns across may be electro- statically accelerated to escape. Fines <=1 micron across are subject to radiation pressure and/or to solar wind drag as soon as they are lofted, and may be quickly entrained to escape even if initially launched at sub-escape velocities. Larger particles levitated in the sub-escape regime remain gravitationally bound to the asteroid and experience lateral transport along local electrostatic and gravity gradients. The particles may migrate across the asteroid's surface indefinitely or, more likely, until they settle in perenially shadowed areas and/or topographic lows (craters or grooves), thus smoothing the asteroid's topography and minimizing shadows. They will remain on the asteroid until ejected by impacts or until the particles are further comminuted by micrometeoritic sandblasting. Remote-sensing studies of asteroids and the examination of meteorite regolithic breccias indicate that, in comparison to the lunar regolith, asteroidal regoliths are generally deficient in fine-grained material <=100 microns across (i.e. in dust and agglutinates) (e.g., [8,9]). This characteristic, usually attributed to the preferential loss of smaller particles by micrometeoritic bombardment [10], may be in part due to electrostatic winnowing. Surface features on Phobos, Deimos and on asteroids 951 Gaspra and 243 Ida (regional albedo-topography relationships [11-13], dark-floored craters [11,14], grooves [11,15], blocks with possible basal debris aprons [16]) appear consistent with an electrophysical mobilization of fines. The inference from polarimetry [17] that the surfaces of M-type asteroids, which are thought to be metal-rich and thus unlikely to evolve strong fields, are finer-grained than most other types of asteroid surfaces suggests that the size of the smallest particles retained on asteroids may indeed be related to their electrophysical properties. Although many unknowns remain with regard to the actual electrophysical properties of asteroid surfaces and to the true effectiveness of the levitation mechanisms invoked, the available models predict interesting results. Electrostatic levitation offers an additional means of particle segregation, transport, and removal on asteroids. The process is expected to be more effective closer to the sun, on less massive objects, on asteroids with a slower spin rate, on the more resistive surfaces, over the more rugged terrain, for less dense particles, and for smaller grains. References: [1] Rennilson J. J. and Criswell D. R. (1974) Moon, 10, 121-142. [2] Berg O. E. et al. (1974) GRL, 1, 289. [3] Whipple E. C. (1981) Rept. Prog. Phys., 44, 1197-1250. [4] Singer S. F. and Walker E. H. (1962) Icarus, 1, 7-12. [5] Mendis D. A. et al. (1981) Astrophys. J., 249, 789-797. [6] Criswell D. R. (1973) in Photons and Particle Interactions with Surfaces in Space (R. Grard, ed.), 545-556. [7] De B. R. and Criswell D. R. (1977) JGR, 82, 999-1004. [8] McKay D. S. et al. (1989) in Asteroids II (R. Binzel et al., eds.), 617-642. [9] Bunch T. E. and Rajan R. S. (1988) in Meteorites and the Early Solar System (J. Kerridge and M. Matthews, eds.), 144-164. [10] Matson D. L. et al. (1977). Proc. LSC 8th, 1001-1011. [11] Thomas P. and Veverka J. (1979) in Asteroids (T. Gehrels, ed.), 628-651. [12] Helfenstein P. et al. (1994) Icarus, 107, 37-60. [13] Helfenstein P. et al. (1995) Icarus, submitted. [14] Sullivan R. et al. (1995) Icarus, submitted. [15] Veverka J. et al. (1994) Icarus, 107, 72-83. [16] Lee P. et al. (1995) Icarus, submitted. [17] Dollfus A. et al. (1989) in Asteroids II (R. Binzel et al., eds.), 594-616.

  7. BILLIARDS: A Demonstration Mission for Hundred-Meter Class Near-Earth Asteroid Disruption

    NASA Technical Reports Server (NTRS)

    Marcus, Matthew; Sloane, Joshua; Ortiz, Oliver; Barbee, Brent William

    2015-01-01

    Collisions from near-Earth asteroids (NEAs) have the potential to cause widespread harm to life on Earth. The hypervelocity nature of these collisions means that a relatively small asteroid (about a quartermile in diameter) could cause a global disaster. Proposed strategies for deflecting or disrupting such a threatening asteroid include detonation of a nuclear explosive device (NED) in close proximity to the asteroid, as well as intercepting the asteroid with a hypervelocity kinetic impactor. NEDs allow for the delivery of large amounts of energy to a NEA for a given mass launched from the Earth, but have not yet been developed or tested for use in deep space. They also present safety and political complications, and therefore may only be used when absolutely necessary. Kinetic impactors require a relatively simple spacecraft compared to NEDs, but also deliver a much lower energy for a given launch mass. To date, no demonstration mission has been conducted for either case, and such a demonstration mission must be conducted prior to the need to utilize them during an actual scenario to ensure that an established, proven system is available for planetary defense when the need arises. One method that has been proposed to deliver a kinetic impactor with impact energy approaching that of an NED is the "billiard-ball" approach. This approach would involve capturing an asteroid approximately ten meters in diameter with a relatively small spacecraft (compared to the launch mass of an equivalent direct kinetic impactor), and redirecting it into the path of an Earth-threatening asteroid. This would cause an impact which would disrupt the Earth-threatening asteroid or deflect it from its Earth-crossing trajectory. The BILLIARDS Project seeks to perform a demonstration of this mission concept in order to establish a protocol that can be used in the event of an impending Earth/asteroid collision. In order to accomplish this objective, the mission must (1) rendezvous with a small (less than 10m), NEA (hereinafter "Alpha"), (2) maneuver Alpha to a collision with a approx. 100 m NEA (hereinafter "Beta"), and (3) produce a detectable deflection or disruption of Beta. In addition to these primary objectives, the BILLIARDS project will contribute to the scientific understanding of the physical properties and collision dynamics of asteroids, and provide opportunities for international collaboration.

  8. Stability and evolution of orbits around the binary asteroid 175706 (1996 FG3): Implications for the MarcoPolo-R mission

    NASA Astrophysics Data System (ADS)

    Hussmann, Hauke; Oberst, Jürgen; Wickhusen, Kai; Shi, Xian; Damme, Friedrich; Lüdicke, Fabian; Lupovka, Valery; Bauer, Sven

    2012-09-01

    In support of the MarcoPolo-R mission, we have carried out numerical simulations of spacecraft trajectories about the binary asteroid 175706 (1996 FG3) under the influence of solar radiation pressure. We study the effects of (1) the asteroid's mass, shape, and rotational parameters, (2) the secondary's mass, shape, and orbit parameters, (3) the spacecraft's mass, surface area, and reflectivity, and (4) the time of arrival, and therefore the relative position to the sun and planets. We have considered distance regimes between 5 and 20 km, the typical range for a detailed characterization of the asteroids - primary and secondary - with imaging systems, spectrometers and by laser altimetry. With solar radiation pressure and gravity forces of the small asteroid competing, orbits are found to be unstable, in general. However, limited orbital stability can be found in the so-called Self-Stabilized Terminator Orbits (SSTO), where initial orbits are circular, orbital planes are oriented approximately perpendicular to the solar radiation pressure, and where the orbital plane of the spacecraft is shifted slightly (between 0.2 and 1 km) from the asteroid in the direction away from the sun. Under the effect of radiation pressure, the vector perpendicular to the orbit plane is observed to follow the sun direction. Shape and rotation parameters of the asteroid as well as gravitational perturbations by the secondary (not to mention sun and planets) were found not to affect the results. Such stable orbits may be suited for long radio tracking runs, which will allow for studying the gravity field. As the effect of the solar radiation pressure depends on the spacecraft mass, shape, and albedo, good knowledge of the spacecraft model and persistent monitoring of the spacecraft orientation are required.

  9. Enhanced Gravity Tractor Derived from the Asteroid Redirect Mission for Deflecting Hypothetical Asteroid 2017 PDC

    NASA Technical Reports Server (NTRS)

    Mazanek, Daniel D.; Reeves, David M.; Abell, Paul A.; Shen, Haijun; Qu, Min

    2017-01-01

    The Asteroid Redirect Mission (ARM) concept would robotically visit a hazardous-size near-Earth asteroid (NEA) with a rendezvous spacecraft, collect a multi-ton boulder and regolith samples from its surface, demonstrate an innovative planetary defense technique known as the Enhanced Gravity Tractor (EGT), and return the asteroidal material to a stable orbit around the Moon, allowing astronauts to explore the returned material in the mid-2020s. Launch of the robotic vehicle to rendezvous with the ARM reference target, NEA (341843) 2008 EV5, would occur in late 2021 [1,2]. The robotic segment of the ARM concept uses a 40 kW Solar Electric Propulsion (SEP) system with a specific impulse (Isp) of 2600 s, and would provide the first ever demonstration of the EGT technique on a hazardous-size asteroid and validate one method of collecting mass in-situ. The power, propellant, and thrust capability of the ARM robotic spacecraft can be scaled from a 40 kW system to 150 kW and 300 kW, which represent a likely future power level progression. The gravity tractor technique uses the gravitational attraction of a station-keeping spacecraft with the asteroid to provide a velocity change and gradually alter the trajectory of the asteroid. EGT utilizes a spacecraft with a high-efficiency propulsion system, such as Solar Electric Propulsion (SEP), along with mass collected in-situ to augment the mass of the spacecraft, thereby increasing the gravitational force between the objects [3]. As long as the spacecraft has sufficient thrust and propellant capability, the EGT force is only limited by the amount of in-situ mass collected and can be increased several orders of magnitude compared to the traditional gravity tractor technique in which only the spacecraft mass is used to generate the gravitational attraction force. This increase in available force greatly reduces the required deflection time. The collected material can be a single boulder, multiple boulders, regolith, or a combination of different material types using a variety of collection techniques. The EGT concept assumes that the ability to efficiently collect asteroid mass in-situ from a wide variety of asteroid types and environments is a future capability that will be developed and perfected in the future by the asteroid mining community. Additionally, it is anticipated that the mass collection would likely be performed by a single or multiple separable spacecraft to allow the SEP spacecraft to operate at safe distance from the asteroid.

  10. The Red Edge Problem in asteroid band parameter analysis

    NASA Astrophysics Data System (ADS)

    Lindsay, Sean S.; Dunn, Tasha L.; Emery, Joshua P.; Bowles, Neil E.

    2016-04-01

    Near-infrared reflectance spectra of S-type asteroids contain two absorptions at 1 and 2 μm (band I and II) that are diagnostic of mineralogy. A parameterization of these two bands is frequently employed to determine the mineralogy of S(IV) asteroids through the use of ordinary chondrite calibration equations that link the mineralogy to band parameters. The most widely used calibration study uses a Band II terminal wavelength point (red edge) at 2.50 μm. However, due to the limitations of the NIR detectors on prominent telescopes used in asteroid research, spectral data for asteroids are typically only reliable out to 2.45 μm. We refer to this discrepancy as "The Red Edge Problem." In this report, we evaluate the associated errors for measured band area ratios (BAR = Area BII/BI) and calculated relative abundance measurements. We find that the Red Edge Problem is often not the dominant source of error for the observationally limited red edge set at 2.45 μm, but it frequently is for a red edge set at 2.40 μm. The error, however, is one sided and therefore systematic. As such, we provide equations to adjust measured BARs to values with a different red edge definition. We also provide new ol/(ol+px) calibration equations for red edges set at 2.40 and 2.45 μm.

  11. Asteroid Risk Assessment: A Probabilistic Approach.

    PubMed

    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.

  12. Hypervelocity impacts on asteroids and momentum transfer I. Numerical simulations using porous targets

    NASA Astrophysics Data System (ADS)

    Jutzi, Martin; Michel, Patrick

    2014-02-01

    In this paper, we investigate numerically the momentum transferred by impacts of small (artificial) projectiles on asteroids. The study of the momentum transfer efficiency as a function of impact conditions and of the internal structure of an asteroid is crucial for performance assessment of the kinetic impactor concept of deflecting an asteroid from its trajectory. The momentum transfer is characterized by the so-called momentum multiplication factor β, which has been introduced to define the momentum imparted to an asteroid in terms of the momentum of the impactor. Here we present results of code calculations of the β factor for porous targets, in which porosity takes the form of microporosity and/or macroporosity. The results of our study using a large range of impact conditions indicate that the momentum multiplication factor β is small for porous targets even for very high impact velocities (β<2 for vimp⩽15 km/s), which is consistent with published scaling laws and results of laboratory experiments (Holsapple, K.A., Housen, K.R. [2012]. Icarus 221, 875-887; Holsapple, K.A., Housen, K.R. [2013]. Proceedings of the IAA Planetary Defense Conference 2013, Flagstaff, USA). It is found that both porosity and strength can have a large effect on the amount of transferred momentum and on the scaling of β with impact velocity. On the other hand, the macroporous inhomogeneities considered here do not have a significant effect on β.

  13. 48 CFR 249.7000 - Terminated contracts with Canadian Commercial Corporation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Canadian Commercial Corporation. 249.7000 Section 249.7000 Federal Acquisition Regulations System DEFENSE... Termination Requirements 249.7000 Terminated contracts with Canadian Commercial Corporation. (a) Terminate contracts with the Canadian Commercial Corporation in accordance with— (1) The Letter of Agreement (LOA...

  14. 48 CFR 249.7000 - Terminated contracts with Canadian Commercial Corporation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Canadian Commercial Corporation. 249.7000 Section 249.7000 Federal Acquisition Regulations System DEFENSE... Termination Requirements 249.7000 Terminated contracts with Canadian Commercial Corporation. (a) Terminate contracts with the Canadian Commercial Corporation in accordance with— (1) The Letter of Agreement (LOA...

  15. 48 CFR 249.7000 - Terminated contracts with Canadian Commercial Corporation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Canadian Commercial Corporation. 249.7000 Section 249.7000 Federal Acquisition Regulations System DEFENSE... Termination Requirements 249.7000 Terminated contracts with Canadian Commercial Corporation. (a) Terminate contracts with the Canadian Commercial Corporation in accordance with— (1) The Letter of Agreement (LOA...

  16. Inappropriate Expression of an NLP Effector in Colletotrichum orbiculare Impairs Infection on Cucurbitaceae Cultivars via Plant Recognition of the C-Terminal Region.

    PubMed

    Azmi, Nur Sabrina Ahmad; Singkaravanit-Ogawa, Suthitar; Ikeda, Kyoko; Kitakura, Saeko; Inoue, Yoshihiro; Narusaka, Yoshihiro; Shirasu, Ken; Kaido, Masanori; Mise, Kazuyuki; Takano, Yoshitaka

    2018-01-01

    The hemibiotrophic pathogen Colletotrichum orbiculare preferentially expresses a necrosis and ethylene-inducing peptide 1 (Nep1)-like protein named NLP1 during the switch to necrotrophy. Here, we report that the constitutive expression of NLP1 in C. orbiculare blocks pathogen infection in multiple Cucurbitaceae cultivars via their enhanced defense responses. NLP1 has a cytotoxic activity that induces cell death in Nicotiana benthamiana. However, C. orbiculare transgenic lines constitutively expressing a mutant NLP1 lacking the cytotoxic activity still failed to infect cucumber, indicating no clear relationship between cytotoxic activity and the NLP1-dependent enhanced defense. NLP1 also possesses the microbe-associated molecular pattern (MAMP) sequence called nlp24, recognized by Arabidopsis thaliana at its central region, similar to NLPs of other pathogens. Surprisingly, inappropriate expression of a mutant NLP1 lacking the MAMP signature is also effective for blocking pathogen infection, uncoupling the infection block from the corresponding MAMP. Notably, the deletion analyses of NLP1 suggested that the C-terminal region of NLP1 is critical to enhance defense in cucumber. The expression of mCherry fused with the C-terminal 32 amino acids of NLP1 was enough to trigger the defense of cucurbits, revealing that the C-terminal region of the NLP1 protein is recognized by cucurbits and, then, terminates C. orbiculare infection.

  17. Robotic Reconnaissance Missions to Small Bodies and Their Potential Contributions to Human Exploration

    NASA Technical Reports Server (NTRS)

    Abell, P. A.; Rivkin, A. S.

    2015-01-01

    Introduction: Robotic reconnaissance missions to small bodies will directly address aspects of NASA's Asteroid Initiative and will contribute to future human exploration. The NASA Asteroid Initiative is comprised of two major components: the Grand Challenge and the Asteroid Mission. The first component, the Grand Challenge, focuses on protecting Earth's population from asteroid impacts by detecting potentially hazardous objects with enough warning time to either prevent them from impacting the planet, or to implement civil defense procedures. The Asteroid Mission involves sending astronauts to study and sample a near- Earth asteroid (NEA) prior to conducting exploration missions of the Martian system, which includes Phobos and Deimos. The science and technical data obtained from robotic precursor missions that investigate the surface and interior physical characteristics of an object will help identify the pertinent physical properties that will maximize operational efficiency and reduce mission risk for both robotic assets and crew operating in close proximity to, or at the surface of, a small body. These data will help fill crucial strategic knowledge gaps (SKGs) concerning asteroid physical characteristics that are relevant for human exploration considerations at similar small body destinations. Small Body Strategic Knowledge Gaps: For the past several years NASA has been interested in identifying the key SKGs related to future human destinations. These SKGs highlight the various unknowns and/or data gaps of targets that the science and engineering communities would like to have filled in prior to committing crews to explore the Solar System. An action team from the Small Bodies Assessment Group (SBAG) was formed specifically to identify the small body SKGs under the direction of the Human Exploration and Operations Missions Directorate (HEOMD), given NASA's recent interest in NEAs and the Martian moons as potential human destinations [1]. The action team organized the SKGs into four broad themes: 1) Identify human mission targets; 2) Understand how to work on and interact with the small body surface; 3) Understand the small body environment and its potential risk/benefit to crew, systems, and operational assets; and 4) Understand the small body resource potential. Each of these themes were then further subdivided into categories to address specific SKG issues. Robotic Precursor Contributions to SKGs: Robotic reconnaissance missions should be able to address specific aspects related to SKG themes 1 through 4. Theme 1 deals with the identification of human mission targets within the NEA population. The current guideline indicates that human missions to fastspinning, tumbling, or binary asteroids may be too risky to conduct successfully from an operational perspective. However, no spacecraft mission has been to any of these types of NEAs before. Theme 2 addresses the concerns about interacting on the small body surface under microgravity conditions, and how the surface and/or sub-surface properties affect or restrict the interaction for human exploration. The combination of remote sensing instruments and in situ payloads will provide good insight into the asteroid's surface and subsurface properties. SKG theme 3 deals with the environment in and around the small body that may present a nuisance or hazard to any assets operating in close proximity. Impact and surface experiments will help address issues related to particle size, particle longevity, internal structure, and the near-surface mechanical stability of the asteroid. Understanding or constraining these physical characteristics are important for mission planning. Theme 4 addresses the resource potential of the small body. This is a particularly important aspect of human exploration since the identification and utilization of resources is a key aspect for deep space mission architectures to the Martian system (i.e., Phobos and Deimos). Conclusions: Robotic reconnaissance of small bodies can provide a wealth of information relevant to the science and planetary defense of NEAs. However, such missions to investigate NEAs can also provide key insights into small body strategic knowledge gaps and contribute to the overall success for human exploration missions to asteroids.

  18. NASA's Asteroid Redirect Mission: The Boulder Capture Option

    NASA Technical Reports Server (NTRS)

    Abell, Paul A.; Nuth, J.; Mazanek, D.; Merrill, R.; Reeves, D.; Naasz, B.

    2014-01-01

    NASA is examining two options for the Asteroid Redirect Mission (ARM), which will return asteroid material to a Lunar Distant Retrograde Orbit (LDRO) using a robotic solar-electric-propulsion spacecraft, called the Asteroid Redirect Vehicle (ARV). Once the ARV places the asteroid material into the LDRO, a piloted mission will rendezvous and dock with the ARV. After docking, astronauts will conduct two extravehicular activities (EVAs) to inspect and sample the asteroid material before returning to Earth. One option involves capturing an entire small (approximately 4-10 m diameter) near-Earth asteroid (NEA) inside a large inflatable bag. However, NASA is examining another option that entails retrieving a boulder (approximately 1-5 m) via robotic manipulators from the surface of a larger (approximately 100+ m) pre-characterized NEA. This option can leverage robotic mission data to help ensure success by targeting previously (or soon to be) well-characterized NEAs. For example, the data from the Hayabusa mission has been utilized to develop detailed mission designs that assess options and risks associated with proximity and surface operations. Hayabusa's target NEA, Itokawa, has been identified as a valid target and is known to possess hundreds of appropriately sized boulders on its surface. Further robotic characterization of additional NEAs (e.g., Bennu and 1999 JU3) by NASA's OSIRIS REx and JAXA's Hayabusa 2 missions is planned to begin in 2018. The boulder option is an extremely large sample-return mission with the prospect of bringing back many tons of well-characterized asteroid material to the Earth-Moon system. The candidate boulder from the target NEA can be selected based on inputs from the world-wide science community, ensuring that the most scientifically interesting boulder be returned for subsequent sampling. This boulder option for NASA's ARM can leverage knowledge of previously characterized NEAs from prior robotic missions, which provides more certainty of the target NEA's physical characteristics and reduces mission risk. This increases the return on investment for NASA's future activities with respect to science, human exploration, resource utilization, and planetary defense

  19. NASA’s Asteroid Redirect Mission: The Boulder Capture Option

    NASA Astrophysics Data System (ADS)

    Abell, Paul; Nuth, Joseph A.; Mazanek, Dan D.; Merrill, Raymond G.; Reeves, David M.; Naasz, Bo J.

    2014-11-01

    NASA is examining two options for the Asteroid Redirect Mission (ARM), which will return asteroid material to a Lunar Distant Retrograde Orbit (LDRO) using a robotic solar-electric-propulsion spacecraft, called the Asteroid Redirect Vehicle (ARV). Once the ARV places the asteroid material into the LDRO, a piloted mission will rendezvous and dock with the ARV. After docking, astronauts will conduct two extravehicular activities (EVAs) to inspect and sample the asteroid material before returning to Earth. One option involves capturing an entire small (˜4-10 m diameter) near-Earth asteroid (NEA) inside a large inflatable bag. However, NASA is examining another option that entails retrieving a boulder (˜1-5 m) via robotic manipulators from the surface of a larger (˜100+ m) pre-characterized NEA. This option can leverage robotic mission data to help ensure success by targeting previously (or soon to be) well-characterized NEAs. For example, the data from the Hayabusa mission has been utilized to develop detailed mission designs that assess options and risks associated with proximity and surface operations. Hayabusa’s target NEA, Itokawa, has been identified as a valid target and is known to possess hundreds of appropriately sized boulders on its surface. Further robotic characterization of additional NEAs (e.g., Bennu and 1999 JU3) by NASA’s OSIRIS REx and JAXA’s Hayabusa 2 missions is planned to begin in 2018. The boulder option is an extremely large sample-return mission with the prospect of bringing back many tons of well-characterized asteroid material to the Earth-Moon system. The candidate boulder from the target NEA can be selected based on inputs from the world-wide science community, ensuring that the most scientifically interesting boulder be returned for subsequent sampling. This boulder option for NASA’s ARM can leverage knowledge of previously characterized NEAs from prior robotic missions, which provides more certainty of the target NEA’s physical characteristics and reduces mission risk. This increases the return on investment for NASA’s future activities with respect to science, human exploration, resource utilization, and planetary defense.

  20. Asteroid Deflection Mission Design Considering On-Ground Risks

    NASA Astrophysics Data System (ADS)

    Rumpf, Clemens; Lewis, Hugh G.; Atkinson, Peter

    The deflection of an Earth-threatening asteroid requires high transparency of the mission design process. The goal of such a mission is to move the projected point of impact over the face of Earth until the asteroid is on a miss trajectory. During the course of deflection operations, the projected point of impact will match regions that were less affected before alteration of the asteroid’s trajectory. These regions are at risk of sustaining considerable damage if the deflecting spacecraft becomes non-operational. The projected impact point would remain where the deflection mission put it at the time of mission failure. Hence, all regions that are potentially affected by the deflection campaign need to be informed about this risk and should be involved in the mission design process. A mission design compromise will have to be found that is acceptable to all affected parties (Schweickart, 2004). A software tool that assesses the on-ground risk due to deflection missions is under development. It will allow to study the accumulated on-ground risk along the path of the projected impact point. The tool will help determine a deflection mission design that minimizes the on-ground casualty and damage risk due to deflection operations. Currently, the tool is capable of simulating asteroid trajectories through the solar system and considers gravitational forces between solar system bodies. A virtual asteroid may be placed at an arbitrary point in the simulation for analysis and manipulation. Furthermore, the tool determines the asteroid’s point of impact and provides an estimate of the population at risk. Validation has been conducted against the solar system ephemeris catalogue HORIZONS by NASA’s Jet Propulsion Laboratory (JPL). Asteroids that are propagated over a period of 15 years show typical position discrepancies of 0.05 Earth radii relative to HORIZONS’ output. Ultimately, results from this research will aid in the identification of requirements for deflection missions that enable effective, minimum risk asteroid deflection. Schweickart, R. L. (2004). THE REAL DEFLECTION DILEMMA. In 2004 Planetary Defense Conference: Protecting Earth from Asteroids (pp. 1-6). Orange County, California. Retrieved from http://b612foundation.org/wp-content/uploads/2013/02/Real_Deflection_Dilemma.pdf

  1. Ballistic missile defense effectiveness

    NASA Astrophysics Data System (ADS)

    Lewis, George N.

    2017-11-01

    The potential effectiveness of ballistic missile defenses today remains a subject of debate. After a brief discussion of terminal and boost phase defenses, this chapter will focus on long-range midcourse defenses. The problems posed by potential countermeasures to such midcourse defenses are discussed as are the sensor capabilities a defense might have available to attempt to discriminate the actual missile warhead in a countermeasures environment. The role of flight testing in assessing ballistic missile defense effectiveness is discussed. Arguments made about effectiveness by missile defense supporters and critics are summarized.

  2. OSIRIS-REx "Uncovering the Secrets of Asteroids" Briefing

    NASA Image and Video Library

    2016-09-07

    In a panel discussion in the Kennedy Space Center’s Operations Support Building II, social media followers were briefed by NASA scientists on asteroids, how they relate to the origins of our solar system and the search for life beyond Earth. The discussion took place before launch of the agency’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer, or OSIRIS-REx spacecraft. Panelists for this conversation are, from the left, Ellen Stofan, NASA chief scientist; Michelle Thaller, deputy director of science communications for NASA’s Science Mission Directorate; Felicia Chou, NASA Communications; Alex Young, associate director for science in the Heliophysics Science Division at NASA’s Goddard Space Flight Center in Greenbelt, Maryland; and Lindley Johnson, director of the Planetary Defense Coordination Office in NASA’s Science Mission Directorate.

  3. NASA's Dawn Mission to Asteroid 4 Vesta

    NASA Technical Reports Server (NTRS)

    McFadden, Lucyann A.

    2011-01-01

    NASA's Dawn Mission to asteroid 4 Vesta is part of a 13-year robotic space project designed to reveal the nature of two of the largest asteroids in the Main Asteroid Belt of our Solar System. Ceres and Vesta are two complementary terrestrial protoplanets whose accretion was probably terminated by the formation of Jupiter. They provide a bridge in our understanding between the rocky bodies of the inner solar system and the icy bodies of the outer solar system. Ceres appears to be undifferentiated Vesta has experienced significant heating and likely differentiation. Both formed very early in history of the solar system and while suffering many impacts have remained intact, thereby retaining a record of events and processes from the time of planet formation. Detailed study of the geophysics and geochemistry of these two bodies provides critical benchmarks for early solar system conditions and processes that shaped its subsequent evolution. Dawn provides the missing context for both primitive and evolved meteoritic data, thus playing a central role in understanding terrestrial planet formation and the evolution of the asteroid belt. Dawn is to he launched in 2006 arriving at Vesta in 20l0 and Ceres in 2014, stopping at each to make 11 months of orbital measurements. The spacecraft uses solar electric propulsion, both in cruise and in orbit, to make most efficient use of its xenon propellant. The spacecraft carries a framing camera, visible and infrared mapping spectrometer, gamma ray/neutron magnetometer, and radio science.

  4. Enhanced Gravity Tractor Technique for Planetary Defense

    NASA Technical Reports Server (NTRS)

    Mazanek, Daniel D.; Reeves, David M.; Hopkins, Joshua B.; Wade, Darren W.; Tantardini, Marco; Shen, Haijun

    2015-01-01

    Given sufficient warning time, Earth-impacting asteroids and comets can be deflected with a variety of different "slow push/pull" techniques. The gravity tractor is one technique that uses the gravitational attraction of a rendezvous spacecraft to the impactor and a low-thrust, high-efficiency propulsion system to provide a gradual velocity change and alter its trajectory. An innovation to this technique, known as the Enhanced Gravity Tractor (EGT), uses mass collected in-situ to augment the mass of the spacecraft, thereby greatly increasing the gravitational force between the objects. The collected material can be a single boulder, multiple boulders, regolith or a combination of different sources. The collected mass would likely range from tens to hundreds of metric tons depending on the size of the impactor and warning time available. Depending on the propulsion system's capability and the mass collected, the EGT approach can reduce the deflection times by a factor of 10 to 50 or more, thus reducing the deflection times of several decades to years or less and overcoming the main criticism of the traditional gravity tractor approach. Additionally, multiple spacecraft can orbit the target in formation to provide the necessary velocity change and further reduce the time needed by the EGT technique to divert hazardous asteroids and comets. The robotic segment of NASA's Asteroid Redirect Mission (ARM) will collect a multi-ton boulder from the surface of a large Near-Earth Asteroid (NEA) and will provide the first ever demonstration of the EGT technique and validate one method of collecting in-situ mass on an asteroid of hazardous size.

  5. NASA's Planetary Defense Coordination Office at NASA HQ

    NASA Astrophysics Data System (ADS)

    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.

  6. NASA's Planetary Defense Coordination Office at NASA HQ

    NASA Astrophysics Data System (ADS)

    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.

  7. Optimal trajectories from the Earth-Moon L1 and L3 points to deflect hazardous asteroids and comets.

    PubMed

    Maccone, Claudio

    2004-05-01

    Software code named asteroff was recently created by the author to simulate the deflection of hazardous asteroids off of their collision course with the Earth. This code was both copyrighted and patented to avoid unauthorized use of ideas that could possibly be vital to construct a planetary defense system in the vicinity of the Earth. Having so said, the basic ideas and equations underlying the asteroff simulation code are openly described in this paper. A system of two space bases housing missiles is proposed to achieve the planetary defense of the Earth against dangerous asteroids and comets, collectively called impactors herein. We show that the layout of the Earth-Moon system with the five relevant Lagrangian (or libration) points in space leads naturally to only one, unmistakable location of these two space bases within the sphere of influence of the Earth. These locations are at the two Lagrangian points L(1) (between the Earth and the Moon) and L(3) (in the direction opposite to the Moon from the Earth). We show that placing missile bases at L(1) and L(3) would enable those missiles to deflect the trajectory of impactors by hitting them orthogonally to their impact trajectory toward the Earth, so as to maximize their deflection. We show that confocal conics are the best class of trajectories fulfilling this orthogonal deflection requirement. One additional remark is that the theory developed in this paper is just a beginning for a wider set of future research. In fact, we only develop the Keplerian analytical theory for the optimal planetary defense achievable from the Earth-Moon Lagrangian points L(1) and L(3). Much more sophisticated analytical refinements would be needed to: (1) take into account many perturbation forces of all kinds acting on both the impactors and missiles shot from L(1) and L(3); (2) add more (non-optimal) trajectories of missiles shot from either the Lagrangian points L(4) and L(5) of the Earth-Moon System or from the surface of the Moon itself; and (3) encompass the full range of missiles currently available to the US (and possibly other countries) so as to really see which impactors could be diverted by which missiles, even in the very simplified scheme outlined here. Published for the first time in February 2002, our Keplerian planetary defense theory has proved, in just one year, to be simple enough to catch the attention of scholars, in addition to popular writers, and even of someone from the US Military. These recent developments might possibly mark the beginning of an all embracing vision in planetary defense beyond all learned congressional activities, dramatic movies, and unknown military plans covered by secrecy.

  8. 32 CFR 746.6 - Nonexclusive license.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 5 2012-07-01 2012-07-01 false Nonexclusive license. 746.6 Section 746.6 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PROCUREMENT, PROPERTY, PATENTS..., or in any lesser geographic portion thereof. (4) After termination of a period specified in the...

  9. 32 CFR 746.6 - Nonexclusive license.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 5 2013-07-01 2013-07-01 false Nonexclusive license. 746.6 Section 746.6 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PROCUREMENT, PROPERTY, PATENTS..., or in any lesser geographic portion thereof. (4) After termination of a period specified in the...

  10. 32 CFR 746.6 - Nonexclusive license.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 5 2011-07-01 2011-07-01 false Nonexclusive license. 746.6 Section 746.6 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PROCUREMENT, PROPERTY, PATENTS..., or in any lesser geographic portion thereof. (4) After termination of a period specified in the...

  11. Missile defense and strategic stability: Terminal High Altitude Area Defense (THAAD) in South Korea

    DOE PAGES

    Sankaran, Jaganath; Fearey, Bryan L.

    2017-02-06

    South Korea is threatened by its troubled relationship with North Korea. North Korea possesses a large cache of missiles as well as chemical and biological weapons, and the future potential to mount nuclear weapons on its missiles. The United States is also challenged because of its defense commitments to Seoul. As a countermeasure, the United States and South Korea decided to deploy Terminal High Altitude Area Defense (THAAD) missile defenses in South Korea. However, China has objected. Chinese scholars believe the THAAD radar would be able to track Chinese inter-continental ballistic missiles, thereby weakening their deterrent. A technical analysis doesmore » not support this assertion. But, it is vital for South Korea, given its proximity and economic interdependence, to reassure China. The United States Forces Korea will deploy THAD and that is not a commitment by Seoul to become part of U.S.-led missile defenses in the Asia-Pacific.« less

  12. Missile defense and strategic stability: Terminal High Altitude Area Defense (THAAD) in South Korea

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

    Sankaran, Jaganath; Fearey, Bryan L.

    South Korea is threatened by its troubled relationship with North Korea. North Korea possesses a large cache of missiles as well as chemical and biological weapons, and the future potential to mount nuclear weapons on its missiles. The United States is also challenged because of its defense commitments to Seoul. As a countermeasure, the United States and South Korea decided to deploy Terminal High Altitude Area Defense (THAAD) missile defenses in South Korea. However, China has objected. Chinese scholars believe the THAAD radar would be able to track Chinese inter-continental ballistic missiles, thereby weakening their deterrent. A technical analysis doesmore » not support this assertion. But, it is vital for South Korea, given its proximity and economic interdependence, to reassure China. The United States Forces Korea will deploy THAD and that is not a commitment by Seoul to become part of U.S.-led missile defenses in the Asia-Pacific.« less

  13. 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.

  14. 48 CFR 32.305 - Loan guarantees for terminated contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... losses and to ensure the loans will be self-liquidating from the proceeds of defense production contracts... REGULATION GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Loan Guarantees for Defense Production 32.305... financing based on the borrower's recoverable investment in defense production contracts, may also apply to...

  15. 48 CFR 32.305 - Loan guarantees for terminated contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... losses and to ensure the loans will be self-liquidating from the proceeds of defense production contracts... REGULATION GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Loan Guarantees for Defense Production 32.305... financing based on the borrower's recoverable investment in defense production contracts, may also apply to...

  16. 48 CFR 32.305 - Loan guarantees for terminated contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... losses and to ensure the loans will be self-liquidating from the proceeds of defense production contracts... REGULATION GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Loan Guarantees for Defense Production 32.305... financing based on the borrower's recoverable investment in defense production contracts, may also apply to...

  17. 48 CFR 32.305 - Loan guarantees for terminated contracts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... losses and to ensure the loans will be self-liquidating from the proceeds of defense production contracts... REGULATION GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Loan Guarantees for Defense Production 32.305... financing based on the borrower's recoverable investment in defense production contracts, may also apply to...

  18. 48 CFR 32.305 - Loan guarantees for terminated contracts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... losses and to ensure the loans will be self-liquidating from the proceeds of defense production contracts... REGULATION GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Loan Guarantees for Defense Production 32.305... financing based on the borrower's recoverable investment in defense production contracts, may also apply to...

  19. OSIRIS-REx "Uncovering the Secrets of Asteroids" Briefing

    NASA Image and Video Library

    2016-09-07

    In a panel discussion in the Kennedy Space Center’s Operations Support Building II, social media followers were briefed by NASA scientists on asteroids, how they relate to the origins of our solar system and the search for life beyond Earth. The discussion took place before launch of the agency’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer, or OSIRIS-REx spacecraft. Panelists in view are, from the left, Felicia Chou, NASA Communications; Alex Young, associate director for science in the Heliophysics Science Division at NASA’s Goddard Space Flight Center in Greenbelt, Maryland; and Lindley Johnson, director of the Planetary Defense Coordination Office in NASA’s Science Mission Directorate. Also participating in the panel discussion are Ellen Stofan, NASA chief scientist and Michelle Thaller, deputy director of science communications for NASA’s Science Mission Directorate.

  20. Detectability of Boulders on Near-Earth Asteroids

    NASA Astrophysics Data System (ADS)

    Miller, Kevin J.; Taylor, Patrick A.; Magri, Christopher; Nolan, Michael C.; Howell, Ellen S.

    2014-11-01

    Boulders are seen on spacecraft images of near-Earth asteroids Eros and Itokawa. Radar images often show bright pixels or groups of pixels that travel consistently across the surface as the object rotates, which may be indicative of similar boulders on other near-Earth asteroids. Examples of these bright pixels were found on radar observations of 2005 YU55 and 2006 VV2 (Benner et al. 2014). Nolan et al. (2013) also identify one large possible boulder on the surface of Bennu, target of the OSIRIS-REx sample return mission. We explore the detectability of boulders by adding synthetic features on asteroid models, and then simulating radar images. These synthetic features were added using BLENDER ver. 2.70, a free open-source 3-D animation suite. Starting with the shape model for Bennu (diameter ~500 m), spherical 'boulders' of 10 m, 20 m, and 40 m diameter were placed at latitudes between 0 and 90 deg. Simulated radar observations of these models indicated that spherical boulders smaller than 10 m may not be visible in observations but that larger ones should be readily seen. Boulders near the sub-Earth point can be hidden in the bright region near the leading edge, but as the asteroid's rotation moves them towards the terminator, they become visible again, with no significant dependence on the latitude of the boulder. These simulations suggest that we should detect large boulders under most circumstances in high-quality radar images, and we have a good estimate of the occurrence of such features on near-Earth objects. Results of these simulations will be presented.

  1. Directed energy deflection laboratory measurements

    NASA Astrophysics Data System (ADS)

    Brashears, Travis; Lubin, Phillip; Hughes, Gary B.; Meinhold, Peter; Suen, Jonathan; Batliner, Payton; Motta, Caio; Griswold, Janelle; Kangas, Miikka; Johansson, Isbella; Alnawakhtha, Yusuf; Prater, Kenyon; Lang, Alex; Madajian, Jonathan

    2015-09-01

    We report on laboratory studies of the effectiveness of directed energy planetary defense as a part of the DESTAR (Directed Energy System for Targeting of Asteroids and exploRation) program. DE-STAR [1][5][6] and DE-STARLITE [2][5][6] are directed energy "stand-off" and "stand-on" programs, respectively. These systems consist of a modular array of kilowatt-class lasers powered by photovoltaics, and are capable of heating a spot on the surface of an asteroid to the point of vaporization. Mass ejection, as a plume of evaporated material, creates a reactionary thrust capable of diverting the asteroid's orbit. In a series of papers, we have developed a theoretical basis and described numerical simulations for determining the thrust produced by material evaporating from the surface of an asteroid [1][2][3][4][5][6]. In the DE-STAR concept, the asteroid itself is used as the deflection "propellant". This study presents results of experiments designed to measure the thrust created by evaporation from a laser directed energy spot. We constructed a vacuum chamber to simulate space conditions, and installed a torsion balance that holds an "asteroid" sample. The sample is illuminated with a fiber array laser with flux levels up to 60 MW/m2 which allows us to simulate a mission level flux but on a small scale. We use a separate laser as well as a position sensitive centroid detector to readout the angular motion of the torsion balance and can thus determine the thrust. We compare the measured thrust to the models. Our theoretical models indicate a coupling coefficient well in excess of 100 μN/Woptical, though we assume a more conservative value of 80 μN/Woptical and then degrade this with an optical "encircled energy" efficiency of 0.75 to 60 μN/Woptical in our deflection modeling. Our measurements discussed here yield about 45 μN/Wabsorbed as a reasonable lower limit to the thrust per optical watt absorbed.

  2. Formulation Assessment and Support Team (FAST) for the Asteroid Redirect Mission (ARM)

    NASA Astrophysics Data System (ADS)

    Mazanek, Daniel D.; Abell, Paul; Reeves, David M.; NASA Asteroid Redirect Mission (ARM) Formulation Assessment and Support Team (FAST)

    2016-10-01

    The Formulation Assessment and Support Team (FAST) for the Asteroid Redirect Mission (ARM) was a two-month effort, chartered by NASA, to provide timely inputs for mission requirement formulation in support of the Asteroid Redirect Robotic Mission (ARRM) Requirements Closure Technical Interchange Meeting held December 15-16, 2015. Additionally, the FAST was tasked with developing an initial list of potential mission investigations and providing input on potential hosted payloads and partnerships. The FAST explored several aspects of potential science benefits and knowledge gain from the ARM. Expertise from the science, engineering, and technology communities was represented in exploring lines of inquiry related to key characteristics of the ARRM reference target asteroid (2008 EV5) for engineering design purposes. Specific areas of interest included target origin, spatial distribution and size of boulders, surface geotechnical properties, boulder physical properties, and considerations for boulder handling, crew safety, and containment. In order to increase knowledge gain potential from the mission, opportunities for partnerships and accompanying payloads that could be provided by domestic and international partners were also investigated. The ARM FAST final report was publicly released on February 18, 2016 and represents the FAST's final product. The report and associated public comments are being used to support mission requirements formulation and serve as an initial inquiry to the science and engineering communities relating to the characteristics of the ARRM reference target asteroid. This report also provides a suggested list of potential investigations sorted and grouped based on their likely benefit to ARM and potential relevance to NASA science and exploration goals. These potential investigations could be conducted to reduce mission risks and increase knowledge return in the areas of science, planetary defense, asteroid resources and in-situ resource utilization (ISRU), and capability and technology demonstrations. This summary presentation will provide an overview of the FAST's effort and associated final report.

  3. Intrepid: Exploring the NEA population with a Fleet of Highly Autonomous SmallSat explorers

    NASA Astrophysics Data System (ADS)

    Blacksberg, Jordana; Chesley, Steven R.; Ehlmann, Bethany; Raymond, Carol Anne

    2017-10-01

    The Intrepid mission concept calls for phased deployment of a fleet of small highly autonomous rendezvous spacecraft designed to characterize the evolution, structure and composition of dozens of Near-Earth Asteroids (NEAs). Intrepid represents a marked departure from conventional solar system exploration projects, where a single unique and complex spacecraft is typically directed to explore a single target body. In contrast, Intrepid relies on the deployment of a large number of autonomous spacecraft to provide redundancy and ensure that the project goals are achieved at a small fraction of the cost of typical missions.The Intrepid science goals are threefold: (1) to understand the evolutionary processes that govern asteroid physical, chemical and dynamical histories and relate these results to solar system origins and evolution; (2) to facilitate impactor deflection scenarios for planetary defense by statistically characterizing relevant asteroid physical properties; (3) to quantify the presence and extractability of potentially useful resources on a large sample of asteroids. To achieve these goals, the baseline architecture includes multiple modular instruments including cameras, spectrometers, radar sounders, and projectiles that could interact with the target asteroid. Key questions to be addressed are: what is the total quantity of water in each object? How is the water incorporated? Are organics present? What is the asteroid physical structure? How would the object respond to impact/deflection?We have begun development of a miniature infrared point spectrometer, a cornerstone of the Intrepid payload, covering both shortwave infrared (SWIR) and mid-infrared (MIR) spectral bands. The spectrometer is designed with a compact 2U form-factor, making it both relevant to Intrepid and implementable on a CubeSat. The combination of SWIR and MIR in a single integrated instrument would enable robust compositional interpretations from a single dataset combining both solar reflectance and thermal emission spectroscopy. These measurements would be crucial to determining the quantity and nature of water present.

  4. From detection to deflection: Mitigation techniques for hidden global threats of natural space objects with short warning time

    NASA Astrophysics Data System (ADS)

    Hussein, Alaa; Rozenheck, Oshri; Entrena Utrilla, Carlos Manuel

    2016-09-01

    Throughout recorded history, hundreds of Earth impacts have been reported, with some catastrophic localized consequences. Based on the International Space University (ISU) Planetary Defense project named READI, we address the impact event problem by giving recommendations for the development of a planetary defense program. This paper reviews the current detection and tracking techniques and gives a set of recommendations for a better preparation to shield Earth from asteroid and cometary impacts. We also extend the use of current deflection techniques and propose a new compilation of those to deflect medium-sized potentially hazardous objects (PHOs). Using an array of techniques from high-energy lasers to defensive missiles, we present a set of protective layers to defend our planet. The paper focused on threats with a short warning period from discovery to impact with Earth, within few years.

  5. Designing Asteroid Impact Scenario Trajectories

    NASA Astrophysics Data System (ADS)

    Chodas, Paul

    2016-05-01

    In order to study some of the technical and geopolitical issues of dealing with an asteroid on impact trajectory, a number of hypothetical impact scenarios have been presented over the last ten years or so. These have been used, for example, at several of the Planetary Defense Conferences (PDCs), as well as in tabletop exercises with the Federal Emergency Management Agency (FEMA), along with other government agencies. The exercise at the 2015 PDC involved most of the attendees, consisted of seven distinct steps (“injects”), and with all the presentations and discussions, took up nearly 10 hours of conference time. The trajectory for the PDC15 scenario was entirely realistic, and was posted ahead of the meeting. It was made available in the NEO Program’s Horizons ephemeris service so that users could , for example, design their own deflection missions. The simulated asteroid and trajectory had to meet numerous very exacting requirements: becoming observable on the very first day of the conference, yet remaining very difficult to observe for the following 7 years, and far enough away from Earth that it was out of reach of radar until just before impact. It had to be undetectable in the past, and yet provide multiple perihelion opportunities for deflection in the future. It had to impact in a very specific region of the Earth, a specific number of years after discovery. When observations of the asteroid are simulated to generate an uncertainty region, that entire region must impact the Earth along an axis that cuts across specific regions of the Earth, the “risk corridor”. This is important because asteroid deflections generally move an asteroid impact point along this corridor. One scenario had a requirement that the asteroid pass through a keyhole several years before impact. The PDC15 scenario had an additional constraint that multiple simulated kinetic impactor missions altered the trajectory at a deflection point midway between discovery and impact. This talk will describe a few recent impact scenarios and outline techniques for finding trajectories that satisfy the complex constraints.

  6. Directed Energy Deflection Laboratory Measurements of Asteroids and Space Debris

    NASA Astrophysics Data System (ADS)

    Brashears, T.; Lubin, P. M.

    2016-12-01

    We report on laboratory studies of the effectiveness of directed energy planetary and space defense as a part of the DE-STAR (Directed Energy System for Targeting of Asteroids and exploRation) program. DE-STAR [1][5][6] and DE-STARLITE [2][5][6] are directed energy "stand-off" and "stand-on" programs, respectively. These systems consist of a modular array of kilowatt-class lasers powered by photovoltaics, and are capable of heating a spot on the surface of an asteroid to the point of vaporization. Mass ejection, as a plume of evaporated material, creates a reactionary thrust capable of diverting the asteroid's orbit. In a series of papers, we have developed a theoretical basis and described numerical simulations for determining the thrust produced by material evaporating from the surface of an asteroid [1][2][3][4][5][6]. In the DE-STAR concept, the asteroid itself is used as the deflection "propellant". This study presents results of experiments designed to measure the thrust created by evaporation from a laser directed energy spot. We constructed a vacuum chamber to simulate space conditions, and installed a torsion balance that holds an "asteroid" or a space debris sample. The sample is illuminated with a fiber array laser with flux levels up to 60 MW/m2 which allows us to simulate a mission level flux but on a small scale. We use a separate laser as well as a position sensitive centroid detector to readout the angular motion of the torsion balance and can thus determine the thrust. We compare the measured thrust to the models. Our theoretical models indicate a coupling coefficient well in excess of 100 µN/Woptical, though we assume a more conservative value of 80 µN/Woptical and then degrade this with an optical "encircled energy" efficiency of 0.75 to 60 µN/Woptical in our deflection modeling. Our measurements discussed here yield about 60 µN/Wabsorbed as a reasonable lower limit to the thrust per optical watt absorbed.

  7. Consequences of Predicted or Actual Asteroid Impacts

    NASA Astrophysics Data System (ADS)

    Chapman, C. R.

    2003-12-01

    Earth impact by an asteroid could have enormous physical and environmental consequences. Impactors larger than 2 km diameter could be so destructive as to threaten civilization. Since such events greatly exceed any other natural or man-made catastrophe, much extrapolation is necessary just to understand environmental implications (e.g. sudden global cooling, tsunami magnitude, toxic effects). Responses of vital elements of the ecosystem (e.g. agriculture) and of human society to such an impact are conjectural. For instance, response to the Blackout of 2003 was restrained, but response to 9/11 terrorism was arguably exaggerated and dysfunctional; would society be fragile or robust in the face of global catastrophe? Even small impacts, or predictions of impacts (accurate or faulty), could generate disproportionate responses, especially if news media reports are hyped or inaccurate or if responsible entities (e.g. military organizations in regions of conflict) are inadequately aware of the phenomenology of small impacts. Asteroid impact is the one geophysical hazard of high potential consequence with which we, fortunately, have essentially no historical experience. It is thus important that decision makers familiarize themselves with the hazard and that society (perhaps using a formal procedure, like a National Academy of Sciences study) evaluate the priority of addressing the hazard by (a) further telescopic searches for dangerous but still-undiscovered asteroids and (b) development of mitigation strategies (including deflection of an oncoming asteroid and on- Earth civil defense). I exemplify these issues by discussing several representative cases that span the range of parameters. Many of the specific physical consequences of impact involve effects like those of other geophysical disasters (flood, fire, earthquake, etc.), but the psychological and sociological aspects of predicted and actual impacts are distinctive. Standard economic cost/benefit analyses may not apply due to the exceptional rarity of major impacts.

  8. A Parameter Study on the Effect of Impactor Size for NASA’s DART Mission

    NASA Astrophysics Data System (ADS)

    Truitt, Amanda; Weaver, Robert; Gisler, Galen

    2018-06-01

    We have modeled the impact of the Double Asteroid Redirection Test (DART) spacecraft into the binary near-Earth asteroid (65803) Didymos. While the primary object is approximately 800 meters across, its secondary body (“moonlet” Didymoon) has a diameter of 150 meters, which is thought to be a much more typical size for the kind of asteroid that would pose a hazard to Earth. DART will be the first demonstration of the kinetic impact technique to change the motion of an asteroid in space, an important consideration for understanding our capabilities in planetary defense of Near-Earth Asteroids. Recent modeling of this impact has used full-density solid aluminum spheres with a mass of approximately 500 kg. Many of the published scaling laws for crater size and diameter as well as ejecta modeling assume this type of impactor, although the actual spacecraft shape being considered for the DART Mission impact is not solid and does not contain a solid dedicated kinetic impactor – rather, the spacecraft itself is considered the impactor. Since the 500 kg hollow spacecraft is significantly larger (~100 x 100 x 200 cm) in size than a solid aluminum sphere (radius ~ 36 cm) the resulting impact dynamics are quite different. Here we have modeled both types of impacts and compare the results of the simulations for crater size, depth, and ejecta for a solid sphere (R = 36 cm) and cylindrical spacecraft (R = 20, 50, and 100 cm), while maintaining a constant mass and material density. This work will allow for a more robust comparison of the momentum enhancement β-factor, which describes the gain in a momentum transfer exerted by the impacting spacecraft on a Near-Earth Object due to ejecta momentum escape. (LA-UR-18-21571)

  9. 44 CFR 332.4 - Termination or modifying voluntary agreements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... AGENCY, DEPARTMENT OF HOMELAND SECURITY PREPAREDNESS VOLUNTARY AGREEMENTS UNDER SECTION 708 OF THE DEFENSE PRODUCTION ACT OF 1950, AS AMENDED § 332.4 Termination or modifying voluntary agreements. The...

  10. 44 CFR 332.4 - Termination or modifying voluntary agreements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... AGENCY, DEPARTMENT OF HOMELAND SECURITY PREPAREDNESS VOLUNTARY AGREEMENTS UNDER SECTION 708 OF THE DEFENSE PRODUCTION ACT OF 1950, AS AMENDED § 332.4 Termination or modifying voluntary agreements. The...

  11. 44 CFR 332.4 - Termination or modifying voluntary agreements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... AGENCY, DEPARTMENT OF HOMELAND SECURITY PREPAREDNESS VOLUNTARY AGREEMENTS UNDER SECTION 708 OF THE DEFENSE PRODUCTION ACT OF 1950, AS AMENDED § 332.4 Termination or modifying voluntary agreements. The...

  12. 44 CFR 332.4 - Termination or modifying voluntary agreements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... AGENCY, DEPARTMENT OF HOMELAND SECURITY PREPAREDNESS VOLUNTARY AGREEMENTS UNDER SECTION 708 OF THE DEFENSE PRODUCTION ACT OF 1950, AS AMENDED § 332.4 Termination or modifying voluntary agreements. The...

  13. 44 CFR 332.4 - Termination or modifying voluntary agreements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... AGENCY, DEPARTMENT OF HOMELAND SECURITY PREPAREDNESS VOLUNTARY AGREEMENTS UNDER SECTION 708 OF THE DEFENSE PRODUCTION ACT OF 1950, AS AMENDED § 332.4 Termination or modifying voluntary agreements. The...

  14. 76 FR 18194 - Termination of Department of Defense Federal Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-01

    ... Military Leadership Diversity Commission. FOR FURTHER INFORMATION CONTACT: Jim Freeman, Deputy Advisory Committee Management Officer for the Department of Defense, 703-601-6128. Dated: March 23, 2011. Morgan F...

  15. NASA Double Asteroid Redirection Test (Dart) Trajectory Validation and Robustness

    NASA Technical Reports Server (NTRS)

    Sarli, Bruno V.; Ozimek, Martin T.; Atchison, Justin A.; Englander, Jacob A.; Barbee, Brent W.

    2017-01-01

    The Double Asteroid Redirection Test (DART) mission will be the first to test the concept of a kinetic impactor. Several studies have been made on asteroid redirection and impact mitigation, however, to this date no mission tested the proposed concepts. An impact study on a representative body allows the measurement of the effects on the target's orbit and physical structure. With this goal, DART's objective is to verify the effectiveness of the kinetic impact concept for planetary defense. The spacecraft uses solar electric propulsion to escape Earth, flyby (138971) 2001 CB21 for impart rehearsal, and impact the secondary body of the (65803) Didymos system. This work focuses on the interplanetary trajectory design part of the mission with the validation of the baseline trajectory, performance comparison to other mission objectives, and assessment of the baseline robustness to missed thrust events. Results show a good performance of the selected trajectory for different mission objectives: latest possible escape date, maximum kinetic energy on impact, shortest possible time of flight, and use of an Earth swing-by. The baseline trajectory was shown to be robust to a missed thrust with 1% of fuel margin being enough to recover the mission for failures of more than 14 days.

  16. Grid-Free 2D Plasma Simulations of the Complex Interaction Between the Solar Wind and Small, Near-Earth Asteroids

    NASA Technical Reports Server (NTRS)

    Zimmerman, M. I.; Farrell, W. M.; Poppe, A. R.

    2014-01-01

    We present results from a new grid-free 2D plasma simulation code applied to a small, unmagnetized body immersed in the streaming solar wind plasma. The body was purposely modeled as an irregular shape in order to examine photoemission and solar wind plasma flow in high detail on the dayside, night-side, terminator and surface-depressed 'pocket' regions. Our objective is to examine the overall morphology of the various plasma interaction regions that form around a small body like a small near-Earth asteroid (NEA). We find that the object obstructs the solar wind flow and creates a trailing wake region downstream, which involves the interplay between surface charging and ambipolar plasma expansion. Photoemission is modeled as a steady outflow of electrons from illuminated portions of the surface, and under direct illumination the surface forms a non-monotonic or ''double-sheath'' electric potential upstream of the body, which is important for understanding trajectories and equilibria of lofted dust grains in the presence of a complex asteroid geometry. The largest electric fields are found at the terminators, where ambipolar plasma expansion in the body-sized night-side wake merges seamlessly with the thin photoelectric sheath on the dayside. The pocket regions are found to be especially complex, with nearby sunlit regions of positive potential electrically connected to unlit negative potentials and forming adjacent natural electric dipoles. For objects near the surface, we find electrical dissipation times (through collection of local environmental solar wind currents) that vary over at least 5 orders of magnitude: from 39 Micro(s) inside the near-surface photoelectron cloud under direct sunlight to less than 1 s inside the particle-depleted night-side wake and shadowed pocket regions

  17. Planetary Defense: Eliminating the Giggle Factor

    DTIC Science & Technology

    2000-01-01

    the coast of the Yucatan Peninsula, and is today credited with ridding the world of the dinosaur menace.1 Since the discovery of these and other...million years, with a less distinct recurrence of larger objects.2 The periodicity of 10 km-size asteroid strikes correlates reasonably well...within the error range of geologic dating) with major global extinction events (as many as ten) recurring on a 26 million year cycle dating back 260

  18. 2015 Southern Taurid fireballs and asteroids 2005 UR and 2005 TF50

    NASA Astrophysics Data System (ADS)

    Olech, A.; Żołądek, P.; Wiśniewski, M.; Rudawska, R.; Bęben, M.; Krzyżanowski, T.; Myszkiewicz, M.; Stolarz, M.; Gawroński, M.; Gozdalski, M.; Suchodolski, T.; Węgrzyk, W.; Tymiński, Z.

    2016-09-01

    On the night of October 31, 2015 two bright Southern Taurid fireballs occurred over Poland, being one of the most spectacular bolides of this shower in recent years. The first fireball - PF311015a Okonek - was detected by six video stations of Polish Fireball Network (PFN) and photographed by several bystanders, allowing for precise determination of the trajectory and orbit of the event. The PF311015a Okonek entered Earth's atmosphere with the velocity of 33.2 ± 0.1 km s-1 and started to shine at height of 117.88 ± 0.05 km. The maximum brightness of -16.0 ± 0.4 mag was reached at height of 82.5 ± 0.1 km. The trajectory of the fireball ended at height of 60.2 ± 0.2 km with terminal velocity of 30.2 ± 1.0 km s-1. The second fireball - PF311015b Ostrowite - was detected by six video stations of PFN. It started with velocity of 33.2 ± 0.1 km s-1 at height of 108.05 ± 0.02 km. The peak brightness of -14.8 ± 0.5 mag was recorded at height of 82.2 ± 0.1 km. The terminal velocity was 31.8 ± 0.5 km s-1 and was observed at height of 57.86 ± 0.03 km. The orbits of both fireballs are similar not only to orbits of Southern Taurids and comet 2P/Encke, but even closer resemblance was noticed for orbits of 2005 UR and 2005 TF50 asteroids. Especially the former object is interesting because of its close flyby during spectacular Taurid maximum in 2005. We carried out a further search to investigate the possible genetic relationship of Okonek and Ostrowite fireballs with both asteroids, that are considered to be associated with Taurid complex. Although, we could not have confirmed unequivocally the relation between fireballs and these objects, we showed that both asteroids could be associated, having the same origin in a disruption process that separates them.

  19. Trajectory design for a lunar mapping and near-Earth-asteroid flyby mission

    NASA Technical Reports Server (NTRS)

    Dunham, David W.; Farquhar, Robert W.

    1993-01-01

    In August, 1994, the unusual asteroid (1620) Geographos will pass very close to the Earth. This provides one of the best opportunities for a low-cost asteroid flyby mission that can be achieved with the help of a gravity assist from the Moon during the years 1994 and 1995. A Geographos flyby mission, including a lunar orbiting phase, was recommended to the Startegic Defense Initiative (SDI) Office when they were searching for ideas for a deep-space mission to test small imaging systems and other lightweight technologies. The goals for this mission, called Clementine, were defined to consist of a comprehensive lunar mapping phase before leaving the Earth-Moon system to encounter Geographos. This paper describes how the authors calculated a trajectory that met the mission goals within a reasonable total Delta-V budget. The paper also describes some refinements of the initially computed trajectory and alternative trajectories were investigated. The paper concludes with a list of trajectories to fly by other near-Earth asteroids during the two years following the Geographos opportunity. Some of these could be used if the Geographos schedule can not be met. If the 140 deg phase angle of the Geographos encounter turns out to be too risky, a flyby of (2120) Tantalus in January, 1995, has a much more favorable approach illumination. Tantalus apparently can be reached from the same lunar orbit needed to get to Geographos. However, both the flyby speed and distance from the Earth are much larger for Tantalus than for Geographos.

  20. Target tracking and pointing for arrays of phase-locked lasers

    NASA Astrophysics Data System (ADS)

    Macasaet, Van P.; Hughes, Gary B.; Lubin, Philip; Madajian, Jonathan; Zhang, Qicheng; Griswold, Janelle; Kulkarni, Neeraj; Cohen, Alexander; Brashears, Travis

    2016-09-01

    Arrays of phase-locked lasers are envisioned for planetary defense and exploration systems. High-energy beams focused on a threatening asteroid evaporate surface material, creating a reactionary thrust that alters the asteroid's orbit. The same system could be used to probe an asteroid's composition, to search for unknown asteroids, and to propel interplanetary and interstellar spacecraft. Phased-array designs are capable of producing high beam intensity, and allow beam steering and beam profile manipulation. Modular designs allow ongoing addition of emitter elements to a growing array. This paper discusses pointing control for extensible laser arrays. Rough pointing is determined by spacecraft attitude control. Lateral movement of the laser emitter tips behind the optical elements provides intermediate pointing adjustment for individual array elements and beam steering. Precision beam steering and beam formation is accomplished by coordinated phase modulation across the array. Added cells are incorporated into the phase control scheme by precise alignment to local mechanical datums using fast, optical relative position sensors. Infrared target sensors are also positioned within the datum scheme, and provide information about the target vector relative to datum coordinates at each emitter. Multiple target sensors allow refined determination of the target normal plane, providing information to the phase controller for each emitter. As emitters and sensors are added, local position data allows accurate prediction of the relative global position of emitters across the array, providing additional constraints to the phase controllers. Mechanical design and associated phase control that is scalable for target distance and number of emitters is presented.

  1. Multi-Organization Multi-Discipline Effort Developing a Mitigation Concept for Planetary Defense

    NASA Technical Reports Server (NTRS)

    Leung, Ronald Y.; Barbee, Brent W.; Seery, Bernard D.; Bambacus, Myra; Finewood, Lee; Greenaugh, Kevin C.; Lewis, Anthony; Dearborn, David; Miller, Paul L.; Weaver, Robert P.; hide

    2017-01-01

    There have been significant recent efforts in addressing mitigation approaches to neutralize Potentially Hazardous Asteroids (PHA). One such research effort was performed in 2015 by an integrated, inter-disciplinary team of asteroid scientists, energy deposition modeling scientists, payload engineers, orbital dynamist engineers, spacecraft discipline engineers, and systems architecture engineer from NASAs Goddard Space Flight Center (GSFC) and the Department of Energy (DoE) National Nuclear Security Administration (NNSA) laboratories (Los Alamos National Laboratory (LANL), Lawrence Livermore National Laboratories (LLNL) and Sandia National Laboratories). The study team collaborated with GSFCs Integrated Design Centers Mission Design Lab (MDL) which engaged a team of GSFC flight hardware discipline engineers to work with GSFC, LANL, and LLNL NEA-related subject matter experts during a one-week intensive concept formulation study in an integrated concurrent engineering environment. This team has analyzed the first of several distinct study cases for a multi-year NASA research grant. This Case 1 study references the Near-Earth Asteroid (NEA) named Bennu as the notional target due to the availability of a very detailed Design Reference Asteroid (DRA) model for its orbit and physical characteristics (courtesy of the Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) mission team). The research involved the formulation and optimization of spacecraft trajectories to intercept Bennu, overall mission and architecture concepts, and high-fidelity modeling of both kinetic impact (spacecraft collision to change a NEAs momentum and orbit) and nuclear detonation effects on Bennu, for purposes of deflecting Bennu.

  2. 32 CFR 219.123 - Early termination of research support: Evaluation of applications and proposals.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 2 2012-07-01 2012-07-01 false Early termination of research support....123 Early termination of research support: Evaluation of applications and proposals. (a) The... finds an institution has materially failed to comply with the terms of this policy. (b) In making...

  3. Stable Orbits in the Didymos Binary Asteroid System - Useful Platforms for Exploration

    NASA Astrophysics Data System (ADS)

    Damme, Friedrich; Hussmann, Hauke; Wickhusen, Kai; Enrico, Mai; Oberst, Jürgen

    2016-04-01

    We have analyzed particle motion in binary asteroid systems to search for stable orbits. In particular, we studied the motion of particles near the asteroid 1996 GT (Didymos), proposed as a target for the AIDA mission. The combined gravity fields of the odd-shaped rotating objects moving about each other are complex. In addition, orbiting spacecraft or dust particles are affected by radiation pressure, possibly exceeding the faint gravitational forces. For the numerical integrations, we adopt parameters for size, shape, and rotation from telescopic observations. To simulate the effect of radiation pressure during a spacecraft mission, we apply a spacecraft wing-box shape model. Integrations were carried out beginning in near-circular orbits over 11 days, during which the motion of the particles were examined. Most orbits are unstable with particles escaping quickly or colliding with the asteroid bodies. However, with carefully chosen initial positions, we found stable motion (in the orbiting plane of the secondary) associated with the Lagrangian points (L4 and L5), in addition to horseshoe orbits, where particles move from one of the Lagrangian point to the other. Finally, we examined orbits in 1:2 resonances with the motion of the orbital period of the secondary. Stable conditions depend strongly on season caused by the inclination of the mutual orbit plane with respect to Didymos solar orbit. At larger distance from the asteroid pair, we find the well-known terminator orbits where gravitational attraction is balanced against radiation pressure. Stable orbits and long motion arcs are useful for long tracking runs by radio or Laser instruments and are well-suited for modelling of the ephemerides of the asteroid pair and gravity field mapping. Furthermore, these orbits may be useful as observing posts or as platforms for approach. These orbits may also represent traps for dust particles, an opportunity for dust collection - or possibly a hazard to spacecraft operation.

  4. What really bothers China about THAAD? 'WHY CHINA BOTHERS ABOUT THAAD MISSILE DEFENSE'

    DOE PAGES

    Sankaran, Jaganath; Fearey, Bryan Leo

    2017-02-07

    The United States has announced that it will deploy Terminal High Altitude Area Defense (THAAD) missile defense system to the Republic of Korea. Here, China has objected as it fears encirclement. The United States should continue to engage with China via official and other channels to mitigate concerns and avoid misperceptions.

  5. What really bothers China about THAAD? 'WHY CHINA BOTHERS ABOUT THAAD MISSILE DEFENSE'

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

    Sankaran, Jaganath; Fearey, Bryan Leo

    The United States has announced that it will deploy Terminal High Altitude Area Defense (THAAD) missile defense system to the Republic of Korea. Here, China has objected as it fears encirclement. The United States should continue to engage with China via official and other channels to mitigate concerns and avoid misperceptions.

  6. Near Earth Asteroid redirect missions based on gravity assist maneuver

    NASA Astrophysics Data System (ADS)

    Ledkov, Anton; Shustov, Boris M.; Eismont, Natan; Boyarsky, Michael; Nazirov, Ravil; Fedyaev, Konstantin

    During last years several events attracted world community attention to the hazards of hitting the Earth by sky objects. One of these objects is Apophis asteroid what was expected with nonzero probability to hit the Earth in 2036. Luckily after more precise measurements this event is considered as practically improbable. But the other object has really reached the Earth, entered the atmosphere in the Chelyabinsk area and caused vast damages. After this the hazardous near Earth objects problem received practical confirmation of the necessity to find the methods of its resolution. The methods to prevent collision of the dangerous sky object with the Earth proposed up to now look not practical enough if one mentions such as gravitational tractor or changing the reflectivity of the asteroid surface. Even the method supposing the targeting of the spacecraft to the hazardous object in order to deflect it from initial trajectory by impact does not work because its low mass as compared with the mass of asteroid to be deflected. For example the mass of the Apophis is estimated to be about 40 million tons but the spacecraft which can be launched to intercept the asteroid using contemporary launchers has the mass not more than 5 tons. So the question arises where to find the heavier projectile which is possible to direct to the dangerous object? The answer proposed in our paper is very simple: to search it among small near Earth asteroids. As small ones we suppose those which have the cross section size not more than 12-15 meters and mass not exceeding 1500 -1700 tons. According to contemporary estimates the number of such asteroids is not less than 100000. The other question is how to redirect such asteroid to the dangerous one. In the paper the possibilities are studied to use for that purpose gravity assist maneuvers near Earth. It is shown that even among asteroids included in contemporary catalogue there are the ones which could be directed to the trajectory of the gravity assist maneuver near Earth resulted by following impact with dangerous asteroid. As example of the last one the Apophis was chosen. The required delta-V pulse to be applied to the candidate projectile asteroid to fulfill mentioned change of initial trajectory was confirmed to be comparatively small: not exceeding 10 m/s, and the smallest is about 2 m/s. To fulfilled this maneuver it is necessary to land and to mount on the surface of the asteroid projectile the spacecraft with sufficient amount of propellant onboard. The possible trajectories and demanded maneuvers were explored and it was confirmed that for contemporary space technology it is doable for the small asteroids belonging to the determined by our studies list of candidates supposing some reservations, namely the mass of the found asteroids. This was not considered as decisive obstacle because up to now only about 1% of small enough asteroids are included in catalogue so the list of the appropriate ones is far from to be closed. The studies have been fulfilled aimed to develop the methods to reached required accuracies of asteroid projectile trajectory parameters determination. With existing methods used for the usual spacecraft the limits of achievable accuracies demand the corrections delta-V maneuvers which may exceed the nominal ones. As a result the proposed conception of hazardous asteroids deflection becomes problematic. To overcome this obstacle in the paper new method of trajectory parameters determination is proposed and explored. Practically it is radio interferometer method when one transponder is placed on the asteroid target and two others together with the asteroid projectile form tetrahedron. This system begins to operate in vicinity of target asteroid in autonomous regime and expected to allow reaching the demanded low enough correction maneuver values. Paper gives the estimations of the accuracy of these three bodies relative motion parameters and expected limit values of correction maneuvers needed for hitting the target object. As additional option of planetary defense system construction the idea to redirect small near Earth asteroids onto the orbits resonance with the Earth orbit is explored. It is shown that it is possible to reach it by the use gravity assist maneuvers as it was described above by applying small velocity impulses to the asteroids. At least 11 asteroids were found demanded small enough delta-V for transferring them on such trajectories. After executing these maneuvers one can receive the system of asteroids approaching to the Earth practically each month with a possibility to use them as projectiles or for the purposes of delivering to the Earth their soil samples.

  7. 48 CFR 249.109 - Settlement agreements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Settlement agreements. 249.109 Section 249.109 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CONTRACT MANAGEMENT TERMINATION OF CONTRACTS General Principles 249.109 Settlement...

  8. Should the USAF be Involved in Planetary Defense

    DTIC Science & Technology

    2009-04-01

    pebbles.6 The impact of most of these objects can be neglected because of their small size. However, there are plenty of other objects in our solar ...the scientific community of end-bringing objects we know about in our solar system is asteroid Apophasis. Astronomers initially thought for a while...the solar system and could come across the orbit of the earth. The density of these objects also varies greatly. Some meteors are made of an almost

  9. NASA Double Asteroid Redirection Test (DART) Trajectory Validation and Robutness

    NASA Technical Reports Server (NTRS)

    Sarli, Bruno V.; Ozimek, Martin T.; Atchison, Justin A.; Englander, Jacob A.; Barbee, Brent W.

    2017-01-01

    The Double Asteroid Redirection Test (DART) mission will be the first to test the concept of a kinetic impactor. Several studies have been made on asteroid redirection and impact mitigation, however, to this date no mission tested the proposed concepts. An impact study on a representative body allows the measurement of the effects on the target's orbit and physical structure. With this goal, DART's objective is to verify the effectiveness of the kinetic impact concept for planetary defense. The spacecraft uses solar electric propulsion to escape Earth, fly by (138971) 2001 CB21 for impact rehearsal, and impact Didymos-B, the secondary body of the binary (65803) Didymos system. This work focuses on the heliocentric transfer design part of the mission with the validation of the baseline trajectory, performance comparison to other mission objectives, and assessment of the baseline robustness to missed thrust events. Results show a good performance of the selected trajectory for different mission objectives: latest possible escape date, maximum kinetic energy on impact, shortest possible time of flight, and use of an Earth swing-by. The baseline trajectory was shown to be robust to a missed thrust with 1% of fuel margin being enough to recover the mission for failures of more than 14 days.

  10. 5 CFR 890.1305 - Termination and cancellation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... REGULATIONS (CONTINUED) FEDERAL EMPLOYEES HEALTH BENEFITS PROGRAM Department of Defense Federal Employees Health Benefits Program Demonstration Project § 890.1305 Termination and cancellation. (a) If an enrolled... beneficiaries and forward them to OPM's Employees Health Benefits Fund. OPM will establish procedures for...

  11. 5 CFR 890.1305 - Termination and cancellation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... REGULATIONS (CONTINUED) FEDERAL EMPLOYEES HEALTH BENEFITS PROGRAM Department of Defense Federal Employees Health Benefits Program Demonstration Project § 890.1305 Termination and cancellation. (a) If an enrolled... beneficiaries and forward them to OPM's Employees Health Benefits Fund. OPM will establish procedures for...

  12. 5 CFR 890.1305 - Termination and cancellation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... REGULATIONS (CONTINUED) FEDERAL EMPLOYEES HEALTH BENEFITS PROGRAM Department of Defense Federal Employees Health Benefits Program Demonstration Project § 890.1305 Termination and cancellation. (a) If an enrolled... beneficiaries and forward them to OPM's Employees Health Benefits Fund. OPM will establish procedures for...

  13. Numerical Investigation of the Consequences of Land Impacts, Water Impacts, or Air Bursts of Asteroids

    NASA Astrophysics Data System (ADS)

    Ezzedine, S. M.; Dearborn, D. S.; Miller, P. L.

    2015-12-01

    The annual probability of an asteroid impact is low, but over time, such catastrophic events are inevitable. Interest in assessing the impact consequences has led us to develop a physics-based framework to seamlessly simulate the event from entry to impact, including air and water shock propagation and wave generation. The non-linear effects are simulated using the hydrodynamics code GEODYN. As effects propagate outward, they become a wave source for the linear-elastic-wave propagation code, WPP/WWP. The GEODYN-WPP/WWP coupling is based on the structured adaptive-mesh-refinement infrastructure, SAMRAI, and has been used in FEMA table-top exercises conducted in 2013 and 2014, and more recently, the 2015 Planetary Defense Conference exercise. Results from these simulations provide an estimate of onshore effects and can inform more sophisticated inundation models. The capabilities of this methodology are illustrated by providing results for different impact locations, and an exploration of asteroid size on the waves arriving at the shoreline of area cities. We constructed the maximum and minimum envelops of water-wave heights given the size of the asteroid and the location of the impact along the risk corridor. Such profiles can inform emergency response and disaster-mitigation efforts, and may be used for design of maritime protection or assessment of risk to shoreline structures of interest. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-675390-DRAFT.

  14. a Direct Observation of the Asteroid's Structure from Deep Interior to Regolith: Two Radars on the Aim Mission

    NASA Astrophysics Data System (ADS)

    Herique, A.; Ciarletti, V.; Plettemeier, D.; Grygorczuk, J.

    2016-12-01

    Our knowledge of the internal structure of asteroids entirely relies on inferences from remote sensing observations of the surface and theoretical modeling. Is the body a monolithic piece of rock or a rubble-pile, how high is the porosity? What is the typical size of the constituent blocs? Are these blocs homogeneous or heterogeneous? The body is covered by a regolith whose properties remain largely unknown in term of depth, size distribution and spatial variability. Is it resulting from fine particles re-accretion or from thermal fracturing? After several asteroid orbiting missions, theses crucial and yet basic questions remain open. Direct measurements of asteroid deep interior and regolith structure are needed to better understand the asteroid accretion and dynamical evolution and to provide answers that will directly improve our ability to understand the formation and evolution of the Near Earth Asteroids (NEA), that will allow us to model the mechanisms driving NEA deflection and other risk mitigation techniques. Radars operating at distance from a spacecraft are the only instruments capable of achieving this science objective of characterizing the internal structure and heterogeneity from submetric to global scale for the benefit of science as well as for planetary defense or exploration. The AIM mission will have two complementary radars on-board, operating at different frequencies in order to meet the objectives requirements. The deep interior structure tomography requires a low-frequency radar (LFR) in order to propagate throughout the complete body and characterize the deep interior: this LFR will be a direct heritage of the CONSERT radar designed for the Rosetta mission. Ihe characterization of the first ten meters of the subsurface with a metric resolution to identify layering and to reconnect surface measurements to internal structure will be achieved with a higher frequency radar (HFR). The design of HFR is based on the WISDOM radar developed for the ExoMars mission. Both radars are currently under phase AB1 funded by ESA. We will present the performances of both instruments on realistic environments and their operating modes.

  15. Planetary Asteroid Defense Study: Assessing and Responding to the Natural Space Debris Threat

    DTIC Science & Technology

    1995-04-01

    Spectrum of Natural Space Debris Effects 82 Figure 5-1. Threat is a Product of Hazard and Risk 84 Figure 5-2. Variables Affecting Threat...are perhaps the most unique family in the extra-belt region. Unlike other families who define their own orbits, the Trojans share Jupiter’s orbit...Threat. We define threat as the relationship between hazard and risk. It can be likened to a product of the two, notionally depicted in Figure 5-1

  16. The C-terminal sequence of several human serine proteases encodes host defense functions.

    PubMed

    Kasetty, Gopinath; Papareddy, Praveen; Kalle, Martina; Rydengård, Victoria; Walse, Björn; Svensson, Bo; Mörgelin, Matthias; Malmsten, Martin; Schmidtchen, Artur

    2011-01-01

    Serine proteases of the S1 family have maintained a common structure over an evolutionary span of more than one billion years, and evolved a variety of substrate specificities and diverse biological roles, involving digestion and degradation, blood clotting, fibrinolysis and epithelial homeostasis. We here show that a wide range of C-terminal peptide sequences of serine proteases, particularly from the coagulation and kallikrein systems, share characteristics common with classical antimicrobial peptides of innate immunity. Under physiological conditions, these peptides exert antimicrobial effects as well as immunomodulatory functions by inhibiting macrophage responses to bacterial lipopolysaccharide. In mice, selected peptides are protective against lipopolysaccharide-induced shock. Moreover, these S1-derived host defense peptides exhibit helical structures upon binding to lipopolysaccharide and also permeabilize liposomes. The results uncover new and fundamental aspects on host defense functions of serine proteases present particularly in blood and epithelia, and provide tools for the identification of host defense molecules of therapeutic interest. Copyright © 2011 S. Karger AG, Basel.

  17. Defense Logistics: Space-Available Travel Challenges May Be Exacerbated If Eligibility Expands

    DTIC Science & Technology

    2012-09-10

    space-available travelers’ use of terminal facilities results in additional maintenance costs for waiting areas, restrooms, and vending machines ...additional required maintenance. For example, additional travelers’ use of waiting areas, restrooms, and vending machines in the terminals could require

  18. Internal gravity, self-energy, and disruption of comets and asteroids

    NASA Astrophysics Data System (ADS)

    Dobrovolskis, Anthony R.; Korycansky, D. G.

    2018-03-01

    The internal gravity and self-gravitational energy of a comet, asteroid, or small moon have applications to their geophysics, including their formation, evolution, cratering, and disruption, the stresses and strains inside such objects, sample return, eventual asteroid mining, and planetary defense strategies for potentially hazardous objects. This paper describes the relation of an object's self-energy to its collisional disruption energy, and shows how to determine an object's self-energy from its internal gravitational potential. Any solid object can be approximated to any desired accuracy by a polyhedron of sufficient complexity. An analytic formula is known for the gravitational potential of any homogeneous polyhedron, but it is widely believed that this formula applies only on the surface or outside of the object. Here we show instead that this formula applies equally well inside the object. We have used these formulae to develop a numerical code which evaluates the self-energy of any homogeneous polyhedron, along with the gravitational potential and attraction both inside and outside of the object, as well as the slope of its surface. Then we use our code to find the internal, external, and surface gravitational fields of the Platonic solids, asteroid (216) Kleopatra, and comet 67P/Churyumov-Gerasimenko, as well as their surface slopes and their self-gravitational energies. We also present simple spherical, ellipsoidal, cuboidal, and duplex models of Kleopatra and comet 67P, and show how to generalize our methods to inhomogeneous objects and magnetic fields. At present, only the self-energies of spheres, ellipsoids, and cuboids (boxes) are known analytically (or semi-analytically). The Supplementary Material contours the central potential and self-energy of homogeneous ellipsoids and cuboids of all aspect ratios, and also analytically the self-gravitational energy of a "duplex" consisting of two coupled spheres. The duplex is a good model for "contact binary" comets and asteroids; in fact, most comets seem to be bilobate, and might be described better as "dirty snowmen" than as "dirty snowballs".

  19. 77 FR 22770 - Termination of Provider Reimbursement Demonstration Project for the State of Alaska

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-17

    ... DEPARTMENT OF DEFENSE Office of the Secretary Termination of Provider Reimbursement Demonstration... Reimbursement Branch, 16401 East Centretech Parkway, Aurora, CO 80011- 9066. FOR FURTHER INFORMATION CONTACT: Glenn J. Corn, TRICARE Management Activity, Medical Benefits and Reimbursement Branch, telephone (303...

  20. 33 CFR 334.1050 - Oakland Outer Harbor adjacent to the Military Ocean Terminal, Bay Area, Pier No. 8 (Port of...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... the Military Ocean Terminal, Bay Area, Pier No. 8 (Port of Oakland Berth No. 10); restricted area. 334..., DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.1050 Oakland Outer Harbor adjacent to the Military Ocean Terminal, Bay Area, Pier No. 8 (Port of Oakland Berth No. 10); restricted area. (a...

  1. 33 CFR 334.1050 - Oakland Outer Harbor adjacent to the Military Ocean Terminal, Bay Area, Pier No. 8 (Port of...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... the Military Ocean Terminal, Bay Area, Pier No. 8 (Port of Oakland Berth No. 10); restricted area. 334..., DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.1050 Oakland Outer Harbor adjacent to the Military Ocean Terminal, Bay Area, Pier No. 8 (Port of Oakland Berth No. 10); restricted area. (a...

  2. 33 CFR 334.1050 - Oakland Outer Harbor adjacent to the Military Ocean Terminal, Bay Area, Pier No. 8 (Port of...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the Military Ocean Terminal, Bay Area, Pier No. 8 (Port of Oakland Berth No. 10); restricted area. 334..., DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.1050 Oakland Outer Harbor adjacent to the Military Ocean Terminal, Bay Area, Pier No. 8 (Port of Oakland Berth No. 10); restricted area. (a...

  3. 33 CFR 334.1050 - Oakland Outer Harbor adjacent to the Military Ocean Terminal, Bay Area, Pier No. 8 (Port of...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... the Military Ocean Terminal, Bay Area, Pier No. 8 (Port of Oakland Berth No. 10); restricted area. 334..., DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.1050 Oakland Outer Harbor adjacent to the Military Ocean Terminal, Bay Area, Pier No. 8 (Port of Oakland Berth No. 10); restricted area. (a...

  4. 33 CFR 334.1050 - Oakland Outer Harbor adjacent to the Military Ocean Terminal, Bay Area, Pier No. 8 (Port of...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... the Military Ocean Terminal, Bay Area, Pier No. 8 (Port of Oakland Berth No. 10); restricted area. 334..., DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.1050 Oakland Outer Harbor adjacent to the Military Ocean Terminal, Bay Area, Pier No. 8 (Port of Oakland Berth No. 10); restricted area. (a...

  5. Planetary Defense Architecture for Mitigating Short-Term Warning Cosmic Threats: READI Project

    NASA Technical Reports Server (NTRS)

    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).

  6. 32 CFR Attachment 5 to Part 855 - Sample Temporary Agreement

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... checks will be performed at the terminal before loading passengers on buses. Luggage on arriving aircraft... routine aircraft maintenance will be accomplished at WAFB. Emergency repairs and or maintenance are only... Part 855 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE AIRCRAFT CIVIL...

  7. 32 CFR Attachment 5 to Part 855 - Sample Temporary Agreement

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... checks will be performed at the terminal before loading passengers on buses. Luggage on arriving aircraft... routine aircraft maintenance will be accomplished at WAFB. Emergency repairs and or maintenance are only... Part 855 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE AIRCRAFT CIVIL...

  8. 32 CFR Attachment 5 to Part 855 - Sample Temporary Agreement

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... checks will be performed at the terminal before loading passengers on buses. Luggage on arriving aircraft... routine aircraft maintenance will be accomplished at WAFB. Emergency repairs and or maintenance are only... Part 855 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE AIRCRAFT CIVIL...

  9. 32 CFR Attachment 5 to Part 855 - Sample Temporary Agreement

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... checks will be performed at the terminal before loading passengers on buses. Luggage on arriving aircraft... routine aircraft maintenance will be accomplished at WAFB. Emergency repairs and or maintenance are only... Part 855 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE AIRCRAFT CIVIL...

  10. 32 CFR Attachment 5 to Part 855 - Sample Temporary Agreement

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... checks will be performed at the terminal before loading passengers on buses. Luggage on arriving aircraft... routine aircraft maintenance will be accomplished at WAFB. Emergency repairs and or maintenance are only... Part 855 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE AIRCRAFT CIVIL...

  11. The Clementine Mission science return at the Moon and Geographos

    NASA Astrophysics Data System (ADS)

    Vorderbruegge, R. W.; Davies, M. E.; Horan, D. M.; Lucey, P. G.; Pieters, C. M.; McEwen, A. S.; Nozette, S.; Shoemaker, E. M.; Squyres, S. W.; Thomas, P. C.

    1993-03-01

    The Clementine Mission is being built and flown by the Naval Research Laboratory under the sponsorship of the Strategic Defense Initiative Organization of the United States Department of Defense in joint-cooperation with NASA, and will explore the Moon and the near-Earth asteroid (NEA) 1620 Geographos with lightweight sensors developed by the Lawrence Livermore National Laboratory. A NASA Science Team for this mission will be selected by way of a NRA in April 1993. The instrument suite includes imaging cameras that cover a spectral range from the near-ultraviolet to the mid-infrared, a laser ranger, and, potentially, a charged particle telescope. To be launched in early 1994, Clementine will be in lunar orbit from February through May 1994, at which time it will depart the Moon for a flyby of 1620 Geographos in August 1994. This mission represents an outstanding opportunity for scientists interested in the Moon and asteroids. It is anticipated that the data returned from this mission will permit: an assessment of global lunar crustal heterogeneity and a resolution of less than 1 km; an assessment of the lithologic heterogeneity of Geographos at a scale of 100 m or better; and an assessment of surface processes on Geographos on the order of 10 m. The basic mission of Clementine and some of the key scientific questions that will be addressed are described. Additional material on the Clementine mission, its data handling and processing, and its instrument suite is presented elsewhere.

  12. Defending Cultural Assets Against a Cosmic Impact Risk

    NASA Astrophysics Data System (ADS)

    Burke, James; Camacho, Sergio

    2016-04-01

    Asteroid or comet impacts on Earth have the potential to destroy humanity's cultural heritage, ranging from local regions to total obliteration. Fortunately we now have means to cope with this hazard -- if and only if we devote resources to finding, intercepting and deflecting threatening objects. Early preparations have already begun. Under auspices of the UN's Committee on the Peaceful Uses of Outer Space (COPUOS) an International Asteroid Warning Network (IAWN) and a Space Mission Planning Advisory Group (SMPAG) have been set up. Upon validation of a threat by IAWN and SMPAG, agencies with capacity, funding and authority to launch intercept missions are to act. A model for this is the existing arrangement for organizing and dispatching UN peacekeeping forces. In this paper we describe current technical options and needed policy and legal developments to enable the world to divert threats and, if that fails or is impossible, to save lives through evacuation and civil defense. In parallel with those efforts, we advocate the creation of safe archives as backup for lost cultural treasures.

  13. Finding and characterizing candidate targets for the Asteroid Redirect Mission (ARM)

    NASA Astrophysics Data System (ADS)

    Chodas, P.

    2014-07-01

    NASA's proposed Asteroid Redirect Mission (ARM) leverages key on-going activities in Human Exploration and Space Technology to advance NASA's goals in these areas. One primary objective of ARM would be to develop and demonstrate a high-power Solar Electric Propulsion (SEP) vehicle which would have the capability of moving significant amounts of mass around the solar system. SEP would be a key technology for robust future missions to deep space destinations, possibly including human missions to asteroids or to Mars. ARM would use the SEP vehicle to redirect up to hundreds of tons of material from a near-Earth asteroid into a stable lunar orbit, where a crew flying in an Orion vehicle would rendezvous and dock with it. The crew would perform an extra-vehicular activity (EVA), sample the material, and bring it back to the Earth; follow-on visits would also be possible. Two ARM mission concepts are being studied: one is to go to a small 4-10-meter-diameter asteroid, capture the entire asteroid and guide it into lunar orbit; the other is to go to a large 100-500 meter asteroid, remove a 1-10 meter boulder, and bring the boulder back into lunar orbit. A planetary defense demonstration could be included under either concept. Although some candidate targets are already known for both mission concepts, an observation campaign has been organized to identify more mission candidates. This campaign naturally leverages off of NASA's NEO Observations Program. Enhancements to asteroid search capabilities which will come online soon should increase the discovery rates for ARM candidates and hazardous asteroids alike. For the small-asteroid ARM concept, candidate targets must be smaller than about 12 meters, must follow Earth-like orbits and must naturally approach the Earth closely in the early 2020s, providing the opportunity for a low-velocity capture into the Earth/Moon system. About a dozen candidates are known with absolute magnitudes in the right range and with orbits suitable for missions launching no earlier than June 2019; the maximum asteroid return masses for these range from 45 to 800 tons according to the orbit. Unfortunately, many of the currently known candidates have not had their sizes, masses and spin rates adequately constrained in order to provide confidence that they are within the capability of the ARM vehicle to return. Still, three candidates have been characterized well enough, two by the Spitzer Space Telescope, 2009 BD and 2011 MD, and one by radar, 2013 EC_{20}. 2009 BD was not actually detected by Spitzer, indicating it was smaller than expected, about 4 meters; similarly, 2013 EC_{20} turned out to be smaller than desired, less than 3 meters. A fourth candidate, 2008 HU_4, should be characterized with radar in 2016 when it passes near the Earth. In general, physical characterization of these very small asteroids is best performed immediately after discovery, while they are still very near the Earth. Radar is important for characterizing size and rotation state, while long-arc high-precision astrometry can help characterize mass through estimation of the area-to-mass ratio. Rapid-response characterization for an ARM candidate was successfully demonstrated last year for 2013 EC_{20}, mentioned earlier. More candidates for the small-asteroid concept are expected: new potential candidates should be detected at the rate of 3 to 5 per year, based on extrapolations from past discovery rates. For the large-asteroid ARM concept, there is an additional characterization challenge: the surface of the asteroid must be observed with enough resolution that the presence of ˜3-meter boulders can be either directly seen or inferred from high-SNR radar. The maximum size and mass of the returnable boulders depends on the asteroid orbit in much the same way as for the other concept. Asteroid Itokawa is a strong candidate because it has already been well characterized by the Japanese Hayabusa spacecraft. The future targets of the OSIRIS-REx and Hayabusa 2 missions, Bennu and 1999 JU_3, should also become strong candidates in 2018. Also considered a valid candidate is 2008 EV_5: radar detected decameter-scale boulders on its surface, from which the presence of returnable ˜3-meter boulders can be inferred. The characterization rate for large-asteroid concept candidates using high-SNR radar is about 1 per year. NASA plans to choose between the two ARM concepts, capture an entire small asteroid versus pick up a boulder from a large one, within about a year.

  14. 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.

  15. 75 FR 82576 - Federal Acquisition Regulation; Terminating Contracts

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-30

    ... Acquisition Council (Councils) agree. The language at FAR 49.501, pertaining to the applicability of FAR part...-AL56 Federal Acquisition Regulation; Terminating Contracts AGENCY: Department of Defense (DoD), General.... SUMMARY: DoD, GSA, and NASA are issuing a final rule amending the Federal Acquisition Regulation (FAR) to...

  16. 22 CFR 124.6 - Termination of manufacturing license agreements and technical assistance agreements.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... and technical assistance agreements. 124.6 Section 124.6 Foreign Relations DEPARTMENT OF STATE... Termination of manufacturing license agreements and technical assistance agreements. The U.S. party to a manufacturing license or a technical assistance agreement must inform the Directorate of Defense Trade Controls...

  17. Observing Campaign for Potential Deep Impact Flyby Target 163249 (2002 GT)

    NASA Technical Reports Server (NTRS)

    Pittichova, Jana; Chesley, S. R.; Abell, P. A.; Benner, L. A. M.

    2012-01-01

    The Deep Impact spacecraft is currently on course for a Jan. 4, 2020 flyby of the sub-kilometer near-Earth asteroid 163249 (2002 GT). The re-targeting will be complete with a final small maneuver scheduled for Oct. 4, 2012. 2002 GT, which is also designated as a Potentially Hazardous Asteroid (PHA), has a well-determined orbit and is approx 800 m in diameter (H=18.3). Little more is known about the nature of this object, but in mid-2013 it will pass near the Earth, affording an exceptional opportunity for ground-based characterization. At this apparition 2002 GT will be in range of Arecibo. In addition to Doppler measurements, radar delay observations with precisions of a few microseconds are expected and have a good chance of revealing whether the system is binary or not. The asteroid will be brighter than 16th mag., which will facilitate a host of observations at a variety of wavelengths. Light curve measurements across a wide range of viewing perspectives will reveal the rotation rate and ultimately lead to strong constraints on the shape and pole orientation. Visible and infrared spectra will constrain the mineralogy, taxonomy, albedo and size. Along with the radar observations, optical astrometry will further constrain the orbit, both to facilitate terminal guidance operations and to potentially reveal nongravitational forces acting on the asteroid. Coordinating all of these observations will be a significant task and we encourage interested observers to collaborate in this effort. The 2013 apparition of 2002 GT represents a unique opportunity to characterize a potential flyby target, which will aid interpretation of the high-resolution flyby imagery and aid planning and development of the flyby imaging sequence. The knowledge gained from this flyby will be highly relevant to the human exploration program at NASA, which desires more information on the physical characteristics of sub-kilometer near-Earth asteroids.

  18. A note on consummation and termination.

    PubMed

    Calef, V; Weinshel, E M

    1983-01-01

    The sensation sometimes expressed by analytic patients, most notably during termination of having left some "unfinished business" (to which they hope to return) is not necessarily simply a judgment about the analysis; frequently it is an affective component of the wish for consummation which has not been granted by the analysis. Simultaneously, it expresses the defense against that very consummation. The wish to give the analyst a gift is in some sense the direct opposite, or more correctly, expresses the defense more openly as a bribe and warning to the analyst that he should not expect or hope for consummation of the instinctual wishes which have been the center of analytic work; i.e., it is a defense against the fulfillment of those wishes almost as if the analyst, by attempting to analyze them, insists upon their enactment. Nevertheless, and despite the apparent contradiction, both affects, which serve similar functions, may appear simultaneously.

  19. FEMA Asteroid Impact Tabletop Exercise Simulations

    DOE PAGES

    Boslough, Mark; Jennings, Barbara; Carvey, Brad; ...

    2015-05-19

    We describe the computational simulations and damage assessments that we provided in support of a tabletop exercise (TTX) at the request of NASA's Near-Earth Objects Program Office. The overall purpose of the exercise was to assess leadership reactions, information requirements, and emergency management responses to a hypothetical asteroid impact with Earth. The scripted exercise consisted of discovery, tracking, and characterization of a hypothetical asteroid; inclusive of mission planning, mitigation, response, impact to population, infrastructure and GDP, and explicit quantification of uncertainty. Participants at the meeting included representatives of NASA, Department of Defense, Department of State, Department of Homeland Security/Federal Emergencymore » Management Agency (FEMA), and the White House. The exercise took place at FEMA headquarters. Sandia's role was to assist the Jet Propulsion Laboratory (JPL) in developing the impact scenario, to predict the physical effects of the impact, and to forecast the infrastructure and economic losses. We ran simulations using Sandia's CTH hydrocode to estimate physical effects on the ground, and to produce contour maps indicating damage assessments that could be used as input for the infrastructure and economic models. We used the FASTMap tool to provide estimates of infrastructure damage over the affected area, and the REAcct tool to estimate the potential economic severity expressed as changes to GDP (by nation, region, or sector) due to damage and short-term business interruptions.« less

  20. FEMA Asteroid Impact Tabletop Exercise Simulations

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

    Boslough, Mark; Jennings, Barbara; Carvey, Brad

    We describe the computational simulations and damage assessments that we provided in support of a tabletop exercise (TTX) at the request of NASA's Near-Earth Objects Program Office. The overall purpose of the exercise was to assess leadership reactions, information requirements, and emergency management responses to a hypothetical asteroid impact with Earth. The scripted exercise consisted of discovery, tracking, and characterization of a hypothetical asteroid; inclusive of mission planning, mitigation, response, impact to population, infrastructure and GDP, and explicit quantification of uncertainty. Participants at the meeting included representatives of NASA, Department of Defense, Department of State, Department of Homeland Security/Federal Emergencymore » Management Agency (FEMA), and the White House. The exercise took place at FEMA headquarters. Sandia's role was to assist the Jet Propulsion Laboratory (JPL) in developing the impact scenario, to predict the physical effects of the impact, and to forecast the infrastructure and economic losses. We ran simulations using Sandia's CTH hydrocode to estimate physical effects on the ground, and to produce contour maps indicating damage assessments that could be used as input for the infrastructure and economic models. We used the FASTMap tool to provide estimates of infrastructure damage over the affected area, and the REAcct tool to estimate the potential economic severity expressed as changes to GDP (by nation, region, or sector) due to damage and short-term business interruptions.« less

  1. Continuity and Change in the Eighties and Beyond. Proceedings of the Natinal Security Affairs Conference (6th) Held 23-25 July 1979, National Defense University.

    DTIC Science & Technology

    1979-11-01

    oilhead to final terminals in Europe. North America. and Japan The oil wofis themselves provide a cluster of obvious targets, as do the collecting ...systems which bring the oil from the fields to the local terminal facilities The collecting system is made up of pumps and pipes The local terminal...but the most important targets are the oil terminals, since it is at these points that the oil from various fields is collected into one place for

  2. 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.

  3. 75 FR 28228 - Federal Acquisition Regulation; FAR Case 2009-031, Terminating Contracts

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-20

    ... alternative clauses that can be used for terminations up to the simplified acquisition threshold. The language... ADMINISTRATION 48 CFR Part 49 [FAR Case 2009-031; Docket 2010-0090, Sequence 1] RIN 9000-AL56 Federal Acquisition...: The Civilian Agency Acquisition Council and the Defense Acquisition Regulations Council (Councils) are...

  4. The Impact Imperative: A Space Infrastructure Enabling a Multi-Tiered Earth Defense

    NASA Technical Reports Server (NTRS)

    Campbell, Jonathan W.; Phipps, Claude; Smalley, Larry; Reilly, James; Boccio, Dona

    2003-01-01

    Impacting at hypervelocity, an asteroid struck the Earth approximately 65 million years ago in the Yucatan Peninsula a m . This triggered the extinction of almost 70% of the species of life on Earth including the dinosaurs. Other impacts prior to this one have caused even greater extinctions. Preventing collisions with the Earth by hypervelocity asteroids, meteoroids, and comets is the most important immediate space challenge facing human civilization. This is the Impact Imperative. We now believe that while there are about 2000 earth orbit crossing rocks greater than 1 kilometer in diameter, there may be as many as 200,000 or more objects in the 100 m size range. Can anything be done about this fundamental existence question facing our civilization? The answer is a resounding yes! By using an intelligent combination of Earth and space based sensors coupled with an infrastructure of high-energy laser stations and other secondary mitigation options, we can deflect inbound asteroids, meteoroids, and comets and prevent them &om striking the Earth. This can be accomplished by irradiating the surface of an inbound rock with sufficiently intense pulses so that ablation occurs. This ablation acts as a small rocket incrementally changing the shape of the rock's orbit around the Sun. One-kilometer size rocks can be moved sufficiently in about a month while smaller rocks may be moved in a shorter time span. We recommend that space objectives be immediately reprioritized to start us moving quickly towards an infrastructure that will support a multiple option defense capability. Planning and development for a lunar laser facility should be initiated immediately in parallel with other options. All mitigation options are greatly enhanced by robust early warning, detection, and tracking resources to find objects sufficiently prior to Earth orbit passage in time to allow significant intervention. Infrastructure options should include ground, LEO, GEO, Lunar, and libration point laser and sensor stations for providing early warning, tracking, and deflection. Other options should include space interceptors that will carry both laser and nuclear ablators for close range work. Response options must be developed to deal with the consequences of an impact should we move too slowly.

  5. System issues and considerations associated with design of ground mobile strategic satellite communication terminals

    NASA Astrophysics Data System (ADS)

    Poliakon, J. A.

    The current national defense doctrine calls for increased use of ground mobile strategic satellite communication earth terminals. This paper discusses some of the key communication terminal system issues and considerations associated with the design of nuclear hardened strategic ground mobile earth terminals. It considers system requirements such as nuclear hardness, rapid mobility, low profile, signal interference resistance, high availability, and long term independent operation. It also discusses impacts and implications associated with these requirements when imposed on a satellite earth terminal. It gives special focus to the ramifications of imposing mobility on earth terminals and its relationship to the system design approach used to arrive at an optimal system solution.

  6. 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.

  7. The OSIRIS-REx Radio Science Experiment at Bennu

    NASA Astrophysics Data System (ADS)

    McMahon, J. W.; Scheeres, D. J.; Hesar, S. G.; Farnocchia, D.; Chesley, S.; Lauretta, D.

    2018-02-01

    The OSIRIS-REx mission will conduct a Radio Science investigation of the asteroid Bennu with a primary goal of estimating the mass and gravity field of the asteroid. The spacecraft will conduct proximity operations around Bennu for over 1 year, during which time radiometric tracking data, optical landmark tracking images, and altimetry data will be obtained that can be used to make these estimates. Most significantly, the main Radio Science experiment will be a 9-day arc of quiescent operations in a 1-km nominally circular terminator orbit. The pristine data from this arc will allow the Radio Science team to determine the significant components of the gravity field up to the fourth spherical harmonic degree. The Radio Science team will also be responsible for estimating the surface accelerations, surface slopes, constraints on the internal density distribution of Bennu, the rotational state of Bennu to confirm YORP estimates, and the ephemeris of Bennu that incorporates a detailed model of the Yarkovsky effect.

  8. The landing of the NEAR-Shoemaker spacecraft on asteroid 433 Eros

    USGS Publications Warehouse

    Veverka, J.; Farquhar, B.; Robinson, M.; Thomas, P.; Murchie, S.; Harch, A.; Antreasian, P.G.; Chesley, S.R.; Miller, J.K.; Owen, W.M.; Williams, B.G.; Yeomans, D.; Dunham, D.; Heyler, G.; Holdridge, M.; Nelson, R.L.; Whittenburg, K.E.; Ray, J.C.; Carcich, B.; Cheng, A.; Chapman, C.; Bell, J.F.; Bell, M.; Bussey, B.; Clark, B.; Domingue, D.; Gaffey, M.J.; Hawkins, E.; Izenberg, N.; Joseph, J.; Kirk, R.; Lucey, P.; Malin, M.; McFadden, L.; Merline, W.J.; Peterson, C.; Prockter, L.; Warren, J.; Wellnitz, D.

    2001-01-01

    The NEAR-Shoemaker spacecraft was designed to provide a comprehensive characterization of the S-type asteroid 433 Eros (refs 1-3), an irregularly shaped body with approximate dimensions of 34 ?? 13 ?? 13 km. Following the completion of its year-long investigation, the mission was terminated with a controlled descent to its surface, in order to provide extremely high resolution images. Here we report the results of the descent on 12 February 2001, during which 70 images were obtained. The landing area is marked by a paucity of small craters and an abundance of 'ejecta blocks'. The properties and distribution of ejecta blocks are discussed in a companion paper. The last sequence of images reveals a transition from the blocky surface to a smooth area, which we interpret as a 'pond'. Properties of the 'ponds' are discussed in a second companion paper. The closest image, from an altitude of 129 m, shows the interior of a 100-m-diameter crater at 1-cm resolution.

  9. Second Line of Defense, Port of Buenos Aires and Exolgan Container Terminal Operational Testing and Evaluation Plan, Buenos Aires, Argentina

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

    Roberts, Bryan W.

    2012-08-23

    The Office of the Second Line of Defense (SLD) Megaports project team for Argentina will conduct operational testing and evaluation (OT&E) at Exolgan Container Terminal at the Port of Dock Sud from July 16-20, 2012; and at the Port of Buenos Aires from September 3-7, 2012. SLD is installing radiation detection equipment to screen export, import, and transshipment containers at these locations. The purpose of OT&E is to validate and baseline an operable system that meets the SLD mission and to ensure the system continues to perform as expected in an operational environment with Argentina Customs effectively adjudicating alarms.

  10. Directed energy deflection laboratory measurements of common space based targets

    NASA Astrophysics Data System (ADS)

    Brashears, Travis; Lubin, Philip; Hughes, Gary B.; Meinhold, Peter; Batliner, Payton; Motta, Caio; Madajian, Jonathan; Mercer, Whitaker; Knowles, Patrick

    2016-09-01

    We report on laboratory studies of the effectiveness of directed energy planetary defense as a part of the DE-STAR (Directed Energy System for Targeting of Asteroids and exploRation) program. DE-STAR and DE-STARLITE are directed energy "stand-off" and "stand-on" programs, respectively. These systems consist of a modular array of kilowatt-class lasers powered by photovoltaics, and are capable of heating a spot on the surface of an asteroid to the point of vaporization. Mass ejection, as a plume of evaporated material, creates a reactionary thrust capable of diverting the asteroid's orbit. In a series of papers, we have developed a theoretical basis and described numerical simulations for determining the thrust produced by material evaporating from the surface of an asteroid. In the DESTAR concept, the asteroid itself is used as the deflection "propellant". This study presents results of experiments designed to measure the thrust created by evaporation from a laser directed energy spot. We constructed a vacuum chamber to simulate space conditions, and installed a torsion balance that holds a common space target sample. The sample is illuminated with a fiber array laser with flux levels up to 60 MW/m2 , which allows us to simulate a mission level flux but on a small scale. We use a separate laser as well as a position sensitive centroid detector to readout the angular motion of the torsion balance and can thus determine the thrust. We compare the measured thrust to the models. Our theoretical models indicate a coupling coefficient well in excess of 100 μN/Woptical, though we assume a more conservative value of 80 μN/Woptical and then degrade this with an optical "encircled energy" efficiency of 0.75 to 60 μN/Woptical in our deflection modeling. Our measurements discussed here yield about 45 μN/Wabsorbed as a reasonable lower limit to the thrust per optical watt absorbed. Results vary depending on the material tested and are limited to measurements of 1 axis, so further tests must be performed.

  11. Eotaxin-3 (CCL26) exerts innate host defense activities that are modulated by mast cell proteases.

    PubMed

    Gela, A; Kasetty, G; Jovic, S; Ekoff, M; Nilsson, G; Mörgelin, M; Kjellström, S; Pease, J E; Schmidtchen, A; Egesten, A

    2015-02-01

    During bacterial infections of the airways, a Th1-profiled inflammation promotes the production of several host defense proteins and peptides with antibacterial activities including β-defensins, ELR-negative CXC chemokines, and the cathelicidin LL-37. These are downregulated by Th2 cytokines of the allergic response. Instead, the eosinophil-recruiting chemokines eotaxin-1/CCL11, eotaxin-2/CCL24, and eotaxin-3/CCL26 are expressed. This study set out to investigate whether these chemokines could serve as innate host defense molecules during allergic inflammation. Antibacterial activities of the eotaxins were investigated using viable count assays, electron microscopy, and methods assessing bacterial permeabilization. Fragments generated by mast cell proteases were characterized, and their potential antibacterial, receptor-activating, and lipopolysaccharide-neutralizing activities were investigated. CCL11, CCL24, and CCL26 all showed potent bactericidal activity, mediated through membrane disruption, against the airway pathogens Streptococcus pneumoniae, Staphylococcus aureus, Nontypeable Haemophilus influenzae, and Pseudomonas aeruginosa. CCL26 retained bactericidal activity in the presence of salt at physiologic concentrations, and the region holding the highest bactericidal activity was the cationic and amphipathic COOH-terminus. Proteolysis of CCL26 by chymase and tryptase, respectively, released distinct fragments of the COOH- and NH2 -terminal regions. The COOH-terminal fragment retained antibacterial activity while the NH2 -terminal had potent LPS-neutralizing properties in the order of CCL26 full-length protein. An identical fragment to NH2 -terminal fragment generated by tryptase was obtained after incubation with supernatants from activated mast cells. None of the fragments activated the CCR3-receptor. Taken together, the findings show that the eotaxins can contribute to host defense against common airway pathogens and that their activities are modulated by mast cell proteases. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Focusing a Transition: Challenges Facing the New Administration

    DTIC Science & Technology

    2016-09-01

    FOCUSING A TRANSITION Challenges Facing the New Administration A Report by the Defense Business Board 2016 This report, DBB Report FY16-5, is a ...Facing the New Administration A Report by the Defense Business Board 5 Table of Contents INTRODUCTION...While reviewing the budget, the team should develop a list of items to propose for immediate termination. The Board offers the following

  13. 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.

  14. Human Expeditions to Near-Earth Asteroids: Implications for Exploration, Resource Utilization, Science, and Planetary Defense

    NASA Technical Reports Server (NTRS)

    Abell, Paul; Mazanek, Dan; Barbee, Brent; Landis, Rob; Johnson, Lindley; Yeomans, Don; Friedensen, Victoria

    2013-01-01

    Over the past several years, much attention has been focused on human exploration of near-Earth asteroids (NEAs) and planetary defence. Two independent NASA studies examined the feasibility of sending piloted missions to NEAs, and in 2009, the Augustine Commission identified NEAs as high profile destinations for human exploration missions beyond the Earth-Moon system as part of the Flexible Path. 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. With respect to planetary defence, in 2005 the U.S. Congress directed NASA to implement a survey program to detect, track, and characterize NEAs equal or greater than 140 m in diameter in order to access the threat from such objects to the Earth. The current goal of this survey is to achieve 90% completion of objects equal or greater than 140 m in diameter by 2020.

  15. 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.

  16. 75 FR 65458 - Renewal of Department of Defense Federal Advisory Committee; Board of Visitors of the U.S. Air...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-25

    ... termination from membership on the Board, pursuant to 10 U.S.C. 9355(c)(2)(A) (``absenteeism provision''). Termination of membership on the Board pursuant to the absenteeism provision, in the case of a member of the... absenteeism provision, the Board's chairperson shall notify the official who designated the member. Upon...

  17. 75 FR 34708 - Notice of Availability of a Final General Conformity Determination and Record of Decision for the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-18

    ... DEPARTMENT OF DEFENSE Department of the Army; Corps of Engineers Notice of Availability of a Final General Conformity Determination and Record of Decision for the Pacific L.A. Marine Terminal LLC Crude Oil Terminal Project, Port of Los Angeles, Los Angeles County, CA AGENCY: Department of the Army--U.S. Army...

  18. 75 FR 53264 - Restricted Area in Cape Fear River and Tributaries at Sunny Point Army Terminal, Brunswick County...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-31

    ... DEPARTMENT OF DEFENSE Department of the Army, Corps of Engineers 33 CFR Part 334 Restricted Area in Cape Fear River and Tributaries at Sunny Point Army Terminal, Brunswick County, NC AGENCY: U.S. Army Corps of Engineers, DoD. ACTION: Proposed rule. SUMMARY: The U.S. Army requested that the U.S...

  19. 75 FR 53197 - Restricted Area in Cape Fear River and Tributaries at Sunny Point Army Terminal, Brunswick County...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-31

    ... DEPARTMENT OF DEFENSE Department of the Army, Corps of Engineers 33 CFR Part 334 Restricted Area in Cape Fear River and Tributaries at Sunny Point Army Terminal, Brunswick County, NC AGENCY: U.S. Army Corps of Engineers, DoD. ACTION: Direct final rule. SUMMARY: The U.S. Army requested that the U.S...

  20. Highest Resolution Gaspra Mosaic

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This picture of asteroid 951 Gaspra is a mosaic of two images taken by the Galileo spacecraft from a range of 5,300 kilometers (3,300 miles), some 10 minutes before closest approach on October 29, 1991. The Sun is shining from the right; phase angle is 50 degrees. The resolution, about 54 meters/pixel, is the highest for the Gaspra encounter and is about three times better than that in the view released in November 1991. Additional images of Gaspra remain stored on Galileo's tape recorder, awaiting playback in November. Gaspra is an irregular body with dimensions about 19 x 12 x 11 kilometers (12 x 7.5 x 7 miles). The portion illuminated in this view is about 18 kilometers (11 miles) from lower left to upper right. The north pole is located at upper left; Gaspra rotates counterclockwise every 7 hours. The large concavity on the lower right limb is about 6 kilometers (3.7 miles) across, the prominent crater on the terminator, center left, about 1.5 kilometers (1 mile). A striking feature of Gaspra's surface is the abundance of small craters. More than 600 craters, 100-500 meters (330-1650 feet) in diameter are visible here. The number of such small craters compared to larger ones is much greater for Gaspra than for previously studied bodies of comparable size such as the satellites of Mars. Gaspra's very irregular shape suggests that the asteroid was derived from a larger body by nearly catastrophic collisions. Consistent with such a history is the prominence of groove-like linear features, believed to be related to fractures. These linear depressions, 100-300 meters wide and tens of meters deep, are in two crossing groups with slightly different morphology, one group wider and more pitted than the other. Grooves had previously been seen only on Mars's moon Phobos, but were predicted for asteroids as well. Gaspra also shows a variety of enigmatic curved depressions and ridges in the terminator region at left. The Galileo project, whose primary mission is the exploration of the Jupiter system in 1995-97, is managed for NASA's Office of Space Science and Applications by the Jet Propulsion Laboratory.

  1. Gaspra - Highest Resolution Mosaic

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This picture of asteroid 951 Gaspra is a mosaic of two images taken by the Galileo spacecraft from a range of 5,300 kilometers (3,300 miles), some 10 minutes before closest approach on October 29, 1991. The Sun is shining from the right; phase angle is 50 degrees. The resolution, about 54 meters/pixel, is the highest for the Gaspra encounter and is about three times better than that in the view released in November 1991. Additional images of Gaspra remain stored on Galileo's tape recorder, awaiting playback in November. Gaspra is an irregular body with dimensions about 19 x 12 x 11 kilometers (12 x 7.5 x 7 miles). The portion illuminated in this view is about 18 kilometers (11 miles) from lower left to upper right. The north pole is located at upper left; Gaspra rotates counterclockwise every 7 hours. The large concavity on the lower right limb is about 6 kilometers (3.7 miles) across, the prominent crater on the terminator, center left, about 1.5 kilometers (1 mile). A striking feature of Gaspra's surface is the abundance of small craters. More than 600 craters, 100-500 meters (330-1650 feet) in diameter are visible here. The number of such small craters compared to larger ones is much greater for Gaspra than for previously studied bodies of comparable size such as the satellites of Mars. Gaspra's very irregular shape suggests that the asteroid was derived from a larger body by nearly catastrophic collisions. Consistent with such a history is the prominence of groove-like linear features, believed to be related to fractures. These linear depressions, 100-300 meters wide and tens of meters deep, are in two crossing groups with slightly different morphology, one group wider and more pitted than the other. Grooves had previously been seen only on Mars's moon Phobos, but were predicted for asteroids as well. Gaspra also shows a variety of enigmatic curved depressions and ridges in the terminator region at left. The Galileo project, whose primary mission is the exploration of the Jupiter system in 1995-97, is managed for NASA's Office of Space Science and Applications by the Jet Propulsion Laboratory.

  2. Optimal Fragmentation and Dispersion of Hazardous Near-Earth Objects

    NASA Technical Reports Server (NTRS)

    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.

  3. Satellite and Ground System Solutions at Your Fingertips

    NASA Technical Reports Server (NTRS)

    2005-01-01

    In the summer of 1998, the blockbuster action movie Armageddon captivated audiences with a thrilling doomsday plot about a meteor the size of Texas that was racing towards the Earth. Though the premise of the movie was purely fictional, the unfortunate reality is that near-Earth asteroids such as the one portrayed in the film do exist. On December 23, 2004, NASA announced that an asteroid it anticipated to pass near the Earth on April 13, 2029, had been assigned the highest score to date on the universally used Torino Impact Hazard Scale. At first, the flyby distance for the asteroid, dubbed MN4, was uncertain and an Earth impact could not be ruled out. The odds of impact were initially believed to be 1 in 300, high enough to merit special monitoring by astronomers around the world, but were then escalated to 1 in 37 on December 27. NASA officials noted, however, that these odds should not be of public concern, since they were likely to change on a day-to-day basis as new data were received. The officials were correct in their assertion, as any chances of an impact with Earth in 2029 were completely ruled out later that same day. Integral Systems, Inc., a leading provider of satellite ground systems and the first company to offer an integrated suite of commercial-off-the-shelf software products for satellite command and control, is helping NASA keep a careful watch for any close-encountering asteroids with its tracking technology. The company supported the first NASA Discovery mission, the Near Earth Asteroid Rendezvous (NEAR) program, back in 1996, and has expanded its business by building more ground systems for a greater variety of satellites than any other company in the world. (NASA has since launched seven more Discovery missions, with the eighth lifting off earlier this year.) The experience gained from the company s participation in developing satellite command and control ground systems for the NEAR program has bolstered its flagship product line, the EPOCH Integrated Product Suite (IPS), first featured in Spinoff 1997, and led to the creation of its latest product, the Skylight Direct Broadcast Ground Terminal.

  4. Multifunctional Information Distribution System (MIDS)

    DTIC Science & Technology

    2013-12-01

    Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to...Estimate DoD - Department of Defense DSN - Defense Switched Network Econ - Economic Eng - Engineering Est - Estimating FMS - Foreign Military Sales FY...fighter aircraft, bombers, helicopters, ships, and ground sites . The MIDS Program consists of the MIDS Low Volume Terminal (MIDS-LVT) and the MIDS

  5. Information and Communication Technologies (ICT) as keys to the enhancement of public awareness about potential earth impacts

    NASA Astrophysics Data System (ADS)

    Usikov, Denis A.

    2013-09-01

    The 2007 Planetary Defense Conference recommends "to provide or enhance Internet sites to show how threats evolve and to illustrate possible action scenarios". Thereby, establishment of informational and communicational AsteroidAware web-site with the exact, authentic data about the past and the present of Earth's impact events will assist in achievement of positive results and progress in different directions on political, international, social and scientific levels. Expanded ICT's capabilities for popularization of planetary defense can help in resolving the problem of low public interest. The project's primary intent lies in popularizing the concept of planetary defenses and attracting attention to the potential dangers that threaten the Earth from outer space. The result of the efforts falling into the boundaries of this project would be an increased amount of social participation in the process of developing solutions for and increasing awareness of potential collisions between various astral bodies and the Earth. The project is also aimed at creating a foundation for the interaction between scientists and executives from around the world to facilitate international efforts of searching for fitting measures towards lowering threat levels and developing strategies revolving around united actions against potential threats.

  6. 48 CFR 245.7001 - Selection, appointment, and termination.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CONTRACT MANAGEMENT GOVERNMENT PROPERTY Appointment of Property... officers, the appointment authority shall consider experience, training, education, business acumen, judgment, character, and ethics. ...

  7. Cometary Defense with Directed Energy

    NASA Astrophysics Data System (ADS)

    Zhang, Q.; Lubin, P. M.; Hughes, G. B.

    2016-12-01

    Cometary impacts pose a long-term hazard to humans on Earth. Due to their comparative rarity, most planetary defense schemes neglect the comet threat, choosing instead to focus exclusively on mitigating asteroid impacts. Methods like kinetic impactors may be suitable for deflecting near-Earth asteroids (NEAs) and Jupiter-family comets (JFCs), both of which are characterized by low inclination orbits and short orbital periods which favor early detection—characteristics ideal for an interception mission. In contrast, Halley-type comets (HTCs) and long-period comets (LPCs) are often found in high inclination orbits rarely more than 2 yr prior to reaching Earth's orbit. Unless discovered and identified in a prior apparition—often centuries or millennia earlier, if ever—timely interception of a threatening HTC or LPC is improbable even with preparation, with missions demanding delta-v budgets often in excess of 30 km/s. Active comets, however, are already naturally perturbed from purely gravitational trajectories through solar-driven sublimation of volatiles. Further deflection may be achieved by supplementing the solar radiation with an artificial directed energy source such as by one or more laser arrays positioned on or near Earth. Simulations were developed with models derived from the known solar nongravitational perturbations of typical comets. Results suggest that a diffraction-limited 500 m array operating at 10 GW for 10 min/day may be sufficient to divert a typical active 500 m comet from an impact given 1 yr. A larger 1 km array operating at 100 GW for 100 s/day is similarly effective. Care must be taken to ensure the target remains intact throughout the deflection period due to comets' low compressive strength and resulting propensity for disintegration at high incident flux.

  8. 48 CFR 232.704-70 - Incrementally funded fixed-price contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING...'s decision and terminate for the convenience of the Government. (c) The contracting officer shall...

  9. Mars Rotational and Orbital Dynamics

    NASA Image and Video Library

    1997-10-14

    The Rotation and Orbit Dynamics experiment is based on measuring the Doppler range to Pathfinder using the radio link. Mars rotation about it's pole causes a signature in the data with a daily minimum when the lander is closest to the Earth. Changes in the daily signature reveal information about the planetary interior, through its effect on Mars' precession and nutation. The signature also is sensitive to variations in Mars' rotation rate as the mass of the atmosphere increases and decreases as the polar caps are formed in winter and evaporate in spring. Long term signatures in the range to the lander are caused by asteroids perturbing Mars' orbit. Analysis of these perturbations allows the determination of the masses of asteroids. Sojourner spent 83 days of a planned seven-day mission exploring the Martian terrain, acquiring images, and taking chemical, atmospheric and other measurements. The final data transmission received from Pathfinder was at 10:23 UTC on September 27, 1997. Although mission managers tried to restore full communications during the following five months, the successful mission was terminated on March 10, 1998. http://photojournal.jpl.nasa.gov/catalog/PIA00975

  10. Quantifying Coastal Hazard of Airburst-Generated Tsunamis

    NASA Astrophysics Data System (ADS)

    Titov, V. V.; Boslough, M.

    2017-12-01

    The effort to prevent or mitigate the effects of an impact on Earth is known as planetary defense. A significant component of planetary defense research involves risk assessment. Much of our understanding of the risk from near-Earth objects comes from the geologic record in the form of impact craters, but not all asteroid impacts are crater-forming events. Small asteroids explode before reaching the surface, generating an airburst, and most impacts into the ocean do not penetrate the water to form a crater in the sea floor. The risk from these non-crater-forming ocean impacts and airbursts is difficult to quantify and represents a significant uncertainty in our assessment of the overall threat. One of the suggested mechanisms for the production of asteroid-generated tsunami is by direct coupling of the pressure wave to the water, analogous to the means by which a moving weather front can generate a meteotsunami. To test this hypothesis, we have run a series of airburst simulations and provided time-resolved pressure and wind profiles for tsunami modelers to use as source functions. We used hydrocodes to model airburst scenarios and provide time dependent boundary conditions as input to shallow-water wave propagation codes. The strongest and most destructive meteotsunami are generated by atmospheric pressure oscillations with amplitudes of only a few hPa, corresponding to changes in sea level of a few cm. The resulting wave is strongest when there is a resonance between the ocean and the atmospheric forcing. The blast wave from an airburst propagates at a speed close to a tsunami speed only in the deepest part of the ocean, and a Proudman resonance cannot be usually achieved even though the overpressures are orders of magnitude greater. However, blast wave profiles are N-waves in which a sharp shock wave leading to overpressure is followed by a more gradual rarefaction to a much longer-duration underpressure phase. Even though the blast outruns the water wave it is forcing, the tsunami should continue to be driven by the out-of-resonance gradient associated with the suction phase, which may depend strongly on the details of the airburst scenario. The open question is whether there are any conditions under which such an airburst can generate tsunami with substantial coastal hazard to contribute to the overall impact risk.

  11. 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.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4024347','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4024347"><span>The Structure of the Human Vaginal Stratum Corneum and its Role in Immune Defense</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Anderson, Deborah J.; Marathe, Jai; Pudney, Jeffrey</p> <p>2014-01-01</p> <p>The superficial layers of the human vaginal epithelium, which form an interface between host and environment, are comprised of dead flattened cells that have undergone a terminal cell differentiation program called cornification. This entails extrusion of nuclei and intercellular organelles, and the depletion of functional DNA and RNA precluding the synthesis of new proteins. As a consequence, the terminally differentiated cells do not maintain robust intercellular junctions and have a diminished capacity to actively respond to microbial exposure, yet the vaginal stratum corneum (SC) mounts an effective defense against invasive microbial infections. The vaginal SC in reproductive aged women is comprised of loosely connected glycogen-filled cells which are permeable to bacterial and viral microbes as well as molecular and cellular mediators of immune defense. We propose here that the vaginal SC provides a unique microenvironment that maintains vaginal health by fostering endogenous lactobacillii and retaining critical mediators of acquired and innate immunity. A better understanding of the molecular and physicochemical properties of the vaginal SC could promote the design of more effective topical drugs and microbicides. PMID:24661416</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050081838','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050081838"><span>Survey of Technologies Relevant to Defense From Near-Earth Objects</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Adams, R. B.; Alexander, R.; Bonometti, J.; Chapman, J.; Fincher, S.; Hopkins, R.; Kalkstein, M.; Polsgrove, T.; Statham, G.; White, S.</p> <p>2004-01-01</p> <p>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.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA122914','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA122914"><span>Industrial Base Actions in a Period of Rising Tensions.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1982-08-01</p> <p>termination liability includin~g those available under Title 3 of - the Defense Production Act (DPA). e Encourage the use of experienced contractor or...start up new suppliers, offering long-term commitments and assuming liability for start-up costs would probably be most effective. Also, the general...and termination liability in the event - of cancellation) to lower-tier firms; *support the extension of DNS/DPS ratings by the Commerce Department to</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20130010670&hterms=asteroid+mining&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dasteroid%2Bmining','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20130010670&hterms=asteroid+mining&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dasteroid%2Bmining"><span>Returning an Entire Near-Earth Asteroid in Support of Human Exploration Beyond Low-Earth Orbit</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brophy, John R.; Friedman, Louis</p> <p>2012-01-01</p> <p>This paper describes the results of a study into the feasibility of identifying, robotically capturing, and returning an entire Near-Earth Asteroid (NEA) to the vicinity of the Earth by the middle of the next decade. The feasibility of such an asteroid retrieval mission hinges on finding an overlap between the smallest NEAs that could be reasonably discovered and characterized and the largest NEAs that could be captured and transported in a reasonable flight time. This overlap appears to be centered on NEAs roughly 7 m in diameter corresponding to masses in the range of 250,000 kg to 1,000,000 kg. The study concluded that it would be possible to return a approx.500,000-kg NEA to high lunar orbit by around 2025. The feasibility is enabled by three key developments: the ability to discover and characterize an adequate number of sufficiently small near-Earth asteroids for capture and return; the ability to implement sufficiently powerful solar electric propulsion systems to enable transportation of the captured NEA; and the proposed human presence in cislunar space in the 2020s enabling exploration and exploitation of the returned NEA. Placing a 500-t asteroid in high lunar orbit would provide a unique, meaningful, and affordable destination for astronaut crews in the next decade. This disruptive capability would have a positive impact on a wide range of the nation's human space exploration interests. It would provide a high-value target in cislunar space that would require a human presence to take full advantage of this new resource. It would offer an affordable path to providing operational experience with astronauts working around and with a NEA that could feed forward to much longer duration human missions to larger NEAs in deep space. It represents a new synergy between robotic and human missions in which robotic spacecraft would retrieve significant quantities of valuable resources for exploitation by astronaut crews to enable human exploration farther out into the solar system. The capture, transportation, examination, and dissection of an entire NEA would provide valuable information for planetary defense activities that may someday have to deflect a much larger near-Earth object. Transportation of the NEA to lunar orbit with a total flight time of 6 to 10 years would be enabled by a 40-kW solar electric propulsion system with a specific impulse of 3,000 s. The flight system could be launched to low-Earth orbit (LEO) on a single Atlas V-class launch vehicle, and return to lunar orbit a NEA with at least 28 times the mass launched to LEO. Longer flight times, higher power SEP systems, or a target asteroid in a particularly favorable orbit could increase the mass amplification factor from 28-to-1 to 70-to-1 or greater. The NASA GRC COMPASS team estimated the full life-cycle cost of an asteroid capture and return mission at approx.$2.6B.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006Icar..182...92V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006Icar..182...92V"><span>Yarkovsky footprints in the Eos family</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vokrouhlický, D.; Brož, M.; Morbidelli, A.; Bottke, W. F.; Nesvorný, D.; Lazzaro, D.; Rivkin, A. S.</p> <p>2006-05-01</p> <p>The Eos asteroid family is the third most populous, after Themis and Koronis, and one of the largest non-random groups of asteroids in the main belt. It has been known and studied for decades, but its structure and history still presented difficulties to understand. We first revise the Eos family identification as a statistical cluster in the space of proper elements. Using the most to-date catalogue of proper elements we determine a nominal Eos family, defined by us using the hierarchical-clustering method with the cut-off velocity of 55 m/s, contains some 4400 members. This unforeseen increase in known Eos asteroids allows us to perform a much more detailed study than was possible so far. We show, in particular, that most of the previously thought peculiar features are explained within the following model: (i) collisional disruption of the parent body leads to formation of a compact family in the proper element space (with characteristic escape velocities of the observed asteroids of tens of meters per second, compatible with hydrocode simulations), and (ii) as time goes, the family dynamically evolves due to a combination of the thermal effects and planetary perturbations. This model allows us to explain sharp termination of the family at the J7/3 mean motion resonance with Jupiter, uneven distribution of family members about the J9/4 mean motion resonance with Jupiter, semimajor axis distribution of large vs small members in the family and anomalous residence of Eos members inside the high-order secular resonance z. Our dynamical method also allows us to estimate Eos family age to 1.3-0.2+0.15 Gyr. Several formal members of the Eos family are in conflict with our model and these are suspected interlopers. We use spectroscopic observations, whose results are also reported here, and results of 5-color wide-band Sloan Digital Sky Survey photometry to prove some of them are indeed spectrally incompatible with the family.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150021375','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150021375"><span>Orbit Stability of OSIRIS-REx in the Vicinity of Bennu Using a High-Fidelity Solar Radiation Model</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Williams, Trevor; Hughes, Kyle; Mashiku, Alinda; Longuski, James</p> <p>2015-01-01</p> <p>The OSIRIS-REx mission (Origins Spectral Interpretation Resource Identification Security Regolith EXPlorer) is an asteroid sample return mission to Bennu (RQ36) that is scheduled to launch in 2016. The planned science operations precluding the small retrieval involve operations in terminator orbits (orbit plane is perpendicular to the sun). Over longer durations the solar radiation pressure (SRP) perturbs the orbit causing it to precess. Our work involves: modeling high fidelity SRP model to capture the perturbations during attitude changes; design a stable orbit from the high fidelity models to analyze the stability over time.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1064597','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1064597"><span>Second Line of Defense Megaports Initiative Operational Testing and Evaluation Plan - Kingston Container Terminal, Port of Kingston, Jamaica</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Deforest, Thomas J.; VanDyke, Damon S.</p> <p>2012-03-01</p> <p>Operational Testing and Evaluation Plan - Kingston Container Terminal, Port of Kingston, Jamaica was written for the Second Line of Defense Megaports Initiative. The purpose of the Operational Testing and Evaluation (OT&E) phase of the project is to prepare for turnover of the Megaports system supplied by U.S. Department of Energy/National Nuclear Security Administration (DOE/NNSA) located at the Kingston Container Terminal (KCT) of the Port of Kingston, Jamaica to the Government of Jamaica (GOJ). Activities conducted during the OT&E phase must demonstrate that the Megaports system can be operated effectively in real time by Jamaica Customs and KCT personnel tomore » the satisfaction of the DOE/NNSA. These activities will also determine if the Megaports system, as installed and accepted, is performing according to the Megaports Program objectives such that the system is capable of executing the mission of the Second Line of Defense Megaports Initiative. The OT&E phase of the project also provides an opportunity to consider potential improvements to the system and to take remedial action if performance deficiencies are identified during the course of evaluation. Changes to the system should be considered under an appropriate change-control process. DOE/NNSA will determine that OT&E is complete by examining whether the Megaports system is performing as intended and that the GOJ is fully capable of operating the system independently without continued onsite support from the U.S. team.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/AD1016759','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/AD1016759"><span>An Assessment of Early Competitive Prototyping for Major Defense Acquisition Programs</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2016-04-30</p> <p>with 20/80 share ratio for EMD; CPFF for test execution. o Percent change in PAUC from development baseline. -2.3%. 3. FAB -T–FET. The Air Force’s...Family of Advanced Beyond Line-of-Sight Terminals ( FAB -T) provides for survivable terminals for communicating strategic nuclear execution orders via...jam-resistant, low probability of intercept waveforms through the Milstar and Advanced Extremely High Frequency (AEHF) satellite constellations. FAB</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA158043','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA158043"><span>How to Fund Cancellation Ceilings on Multiyear Defense Contracts: A Risk Pooling Alternative</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1985-01-01</p> <p>R t- Government faces a termination liability after the first year of the contract for EOQ material. This causes a need for higher authorizations...le items to the Defense inventory. EOQ liability on multiyear programs is currently fully funded to guarantee delivery of all prior- year systems...ýach program years’ buy of systems and the entire EOQ liability each year. -- Best satisfies Congress’ desire for protection against long-term</p> </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"><span>13</span></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><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <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"><span>14</span></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> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=151473','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=151473"><span>Genome Dynamics and Evolution of the Mla (Powdery Mildew) Resistance Locus in BarleyW⃞</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wei, Fusheng; Wing, Rod A.; Wise, Roger P.</p> <p>2002-01-01</p> <p>Genes that confer defense against pathogens often are clustered in the genome and evolve via diverse mechanisms. To evaluate the organization and content of a major defense gene complex in cereals, we determined the complete sequence of a 261-kb BAC contig from barley cv Morex that spans the Mla (powdery mildew) resistance locus. Among the 32 predicted genes on this contig, 15 are associated with plant defense responses; 6 of these are associated with defense responses to powdery mildew disease but function in different signaling pathways. The Mla region is organized as three gene-rich islands separated by two nested complexes of transposable elements and a 45-kb gene-poor region. A heterochromatic-like region is positioned directly proximal to Mla and is composed of a gene-poor core with 17 families of diverse tandem repeats that overlap a hypermethylated, but transcriptionally active, gene-dense island. Paleontology analysis of long terminal repeat retrotransposons indicates that the present Mla region evolved over a period of >7 million years through a variety of duplication, inversion, and transposon-insertion events. Sequence-based recombination estimates indicate that R genes positioned adjacent to nested long terminal repeat retrotransposons, such as Mla, do not favor recombination as a means of diversification. We present a model for the evolution of the Mla region that encompasses several emerging features of large cereal genomes. PMID:12172030</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title48-vol1/pdf/CFR-2010-title48-vol1-sec47-301-3.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title48-vol1/pdf/CFR-2010-title48-vol1-sec47-301-3.pdf"><span>48 CFR 47.301-3 - Using the Defense Transportation System (DTS).</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-10-01</p> <p>... implemented on a world-wide basis. (b) Contracting activities are responsible for (1) ensuring that the... directly to a military air or water port terminal without authorization from the designated contract...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000057504','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000057504"><span>Near Earth Asteroid Rendezvous (NEAR) Revised Eros Orbit Phase Trajectory Design</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Helfrich, J; Miller, J. K.; Antreasian, P. G.; Carranza, E.; Williams, B. G.; Dunham, D. W.; Farquhar, R. W.; McAdams, J. V.</p> <p>1999-01-01</p> <p>Trajectory design of the orbit phase of the NEAR mission involves a new process that departs significantly from those procedures used in previous missions. In most cases, a precise spacecraft ephemeris is designed well in advance of arrival at the target body. For NEAR, the uncertainty in the dynamic environment around Eros does not allow the luxury of a precise spacecraft trajectory to be defined in advance. The principal cause of this uncertainty is the limited knowledge oi' the gravity field a,-id rotational state of Eros. As a result, the concept for the NEAR trajectory design is to define a number of rules for satisfying spacecraft, mission, and science constraints, and then apply these rules to various assumptions for the model of Eros. Nominal, high, and low Eros mass models are used for testing the trajectory design strategy and to bracket the ranges of parameter variations that are expected upon arrival at the asteroid. The final design is completed after arrival at Eros and determination of the actual gravity field and rotational state. As a result of the unplanned termination of the deep space rendezvous maneuver on December 20, 1998, the NEAR spacecraft passed within 3830 km of Eros on December 23, 1998. This flyby provided a brief glimpse of Eros, and allowed for a more accurate model of the rotational parameters and gravity field uncertainty. Furthermore, after the termination of the deep space rendezvous burn, contact with the spacecraft was lost and the NEAR spacecraft lost attitude control. During the subsequent gyrations of the spacecraft, hydrazine thruster firings were used to regain attitude control. This unplanned thruster activity used Much of the fuel margin allocated for the orbit phase. Consequently, minimizing fuel consumption is now even more important.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002iaf..confE.138B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002iaf..confE.138B"><span>Impact: an Integrated Approach (Space and Ground) for Monitoring the Threat of Earth Orbit Corssing Celestial Bodies</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bussolino, L.; Somma, R.</p> <p></p> <p>The threat of possible collision of asteroids and comets with our planet has reached an international stage since 1990 when U.S.A. Congress set up a dedicated committee for the analysis and the assessment of this problem.The U.N. organized a congress later on to summarize the current knowledge on this subject as well as the Europea Council recommended its member states to conduct studies to further deepen the understanding in terms of tackling and solving this kind of problem interesting the entire world. IMPACT is the acronym for " International Monitoring Program for Asteroids and Comets Threats " coming out as proposal from a study funded by the italian region PIEMONTE throughout the Civil Protection Bureau and performed by the Planetology Group of the Astronomical Observatory of Torino ( Italy ) and Alenia Spazio for the engineering part. They have carried out a series of analyses aimed at contributing in subsequent steps to the solution of the two fundamental problems associated to the potential impact threat : the assessment of the numbers of killers/terminators and the impact rates from one side and the development of the idea of considering space segments for supporting activities of discovery as well as the physical and mineralogical characterization using satellites in orbit around the Earth. other additional studies also funded by the European Space Agency where the space technology appears to offer a great contribution if conveniently integrated with the Earth networks for Potentially Hazardous Asteroids ( PHA ) detection. An international approach for monitoring this threat for the Earth is then proposed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MNRAS.463..705C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MNRAS.463..705C"><span>On the highly inclined vW leptokurtic asteroid families</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carruba, V.; Domingos, R. C.; Aljbaae, S.; Huaman, M.</p> <p>2016-11-01</p> <p>vW leptokurtic asteroid families are families for which the distribution of the normal component of the terminal ejection velocity field vW is characterized by a positive value of the γ2 Pearson kurtosis, I.e. they have a distribution with a more concentrated peak and larger tails than the Gaussian one. Currently, eight families are known to have γ2(vW) > 0.25. Among these, three are highly inclined asteroid families, the Hansa, Barcelona, and Gallia families. As observed for the case of the Astrid family, the leptokurtic inclination distribution seems to be caused by the interaction of these families with node secular resonances. In particular, the Hansa and Gallia family are crossed by the s - sV resonance with Vesta, that significantly alters the inclination of some of their members. In this work we use the time evolution of γ2(vW) for simulated families under the gravitational influence of all planets and the three most massive bodies in the main belt to assess the dynamical importance (or lack of) node secular resonances with Ceres, Vesta, and Pallas for the considered families, and to obtain independent constraints on the family ages. While secular resonances with massive bodies in the main belt do not significantly affect the dynamical evolution of the Barcelona family, they significantly increase the γ2(vW) values of the simulated Hansa and Gallia families. Current values of the γ2(vW) for the Gallia family are reached over the estimated family age only if secular resonances with Vesta are accounted for.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/22293658-terminating-safeguards-excess-special-nuclear-material-defense-tru-waste-clean-up-nonproliferation','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22293658-terminating-safeguards-excess-special-nuclear-material-defense-tru-waste-clean-up-nonproliferation"><span></span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Hayes, Timothy; Nelson, Roger</p> <p></p> <p>The Department of Energy (DOE) and the National Nuclear Security Administration (NNSA) manages defense nuclear material that has been determined to be excess to programmatic needs and declared waste. When these wastes contain plutonium, they almost always meet the definition of defense transuranic (TRU) waste and are thus eligible for disposal at the Waste Isolation Pilot Plant (WIPP). The DOE operates the WIPP in a manner that physical protections for attractiveness level D or higher special nuclear material (SNM) are not the normal operating condition. Therefore, there is currently a requirement to terminate safeguards before disposal of these wastes atmore » the WIPP. Presented are the processes used to terminate safeguards, lessons learned during the termination process, and how these approaches might be useful for future defense TRU waste needing safeguards termination prior to shipment and disposal at the WIPP. Also described is a new criticality control container, which will increase the amount of fissile material that can be loaded per container, and how it will save significant taxpayer dollars. Retrieval, compliant packaging and shipment of retrievably stored legacy TRU waste has dominated disposal operations at WIPP since it began operations 12 years ago. But because most of this legacy waste has successfully been emplaced in WIPP, the TRU waste clean-up focus is turning to newly-generated TRU materials. A major component will be transuranic SNM, currently managed in safeguards-protected vaults around the weapons complex. As DOE and NNSA continue to consolidate and shrink the weapons complex footprint, it is expected that significant quantities of transuranic SNM will be declared surplus to the nation's needs. Safeguards termination of SNM varies due to the wide range of attractiveness level of the potential material that may be directly discarded as waste. To enhance the efficiency of shipping waste with high TRU fissile content to WIPP, DOE designed an over-pack container, similar to the pipe component, called the criticality control over-pack, which will significantly enhance the efficiency of disposal. Hundreds of shipments of transuranic SNM, suitably packaged to meet WIPP waste acceptance criteria and with safeguards terminated have been successfully emplaced at WIPP (primarily from the Rocky Flats site clean-up) since WIPP opened. DOE expects that thousands more may eventually result from SNM consolidation efforts throughout the weapons complex. (authors)« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1992NASSP.509C.111G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1992NASSP.509C.111G"><span>Asteroid mining</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gertsch, Richard E.</p> <p></p> <p>The earliest studies of asteroid mining proposed retrieving a main belt asteroid. Because of the very long travel times to the main asteroid belt, attention has shifted to the asteroids whose orbits bring them fairly close to the Earth. In these schemes, the asteroids would be bagged and then processed during the return trip, with the asteroid itself providing the reaction mass to propel the mission homeward. A mission to one of these near-Earth asteroids would be shorter, involve less weight, and require a somewhat lower change in velocity. Since these asteroids apparently contain a wide range of potentially useful materials, our study group considered only them. The topics covered include asteroid materials and properties, asteroid mission selection, manned versus automated missions, mining in zero gravity, and a conceptual mining method.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930007695','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930007695"><span>Asteroid mining</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gertsch, Richard E.</p> <p>1992-01-01</p> <p>The earliest studies of asteroid mining proposed retrieving a main belt asteroid. Because of the very long travel times to the main asteroid belt, attention has shifted to the asteroids whose orbits bring them fairly close to the Earth. In these schemes, the asteroids would be bagged and then processed during the return trip, with the asteroid itself providing the reaction mass to propel the mission homeward. A mission to one of these near-Earth asteroids would be shorter, involve less weight, and require a somewhat lower change in velocity. Since these asteroids apparently contain a wide range of potentially useful materials, our study group considered only them. The topics covered include asteroid materials and properties, asteroid mission selection, manned versus automated missions, mining in zero gravity, and a conceptual mining method.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20592020','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20592020"><span>C-terminal peptides of tissue factor pathway inhibitor are novel host defense molecules.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Papareddy, Praveen; Kalle, Martina; Kasetty, Gopinath; Mörgelin, Matthias; Rydengård, Victoria; Albiger, Barbara; Lundqvist, Katarina; Malmsten, Martin; Schmidtchen, Artur</p> <p>2010-09-03</p> <p>Tissue factor pathway inhibitor (TFPI) inhibits tissue factor-induced coagulation, but may, via its C terminus, also modulate cell surface, heparin, and lipopolysaccharide interactions as well as participate in growth inhibition. Here we show that C-terminal TFPI peptide sequences are antimicrobial against the gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, gram-positive Bacillus subtilis and Staphylococcus aureus, as well as the fungi Candida albicans and Candida parapsilosis. Fluorescence studies of peptide-treated bacteria, paired with analysis of peptide effects on liposomes, showed that the peptides exerted membrane-breaking effects similar to those seen for the "classic" human antimicrobial peptide LL-37. The killing of E. coli, but not P. aeruginosa, by the C-terminal peptide GGLIKTKRKRKKQRVKIAYEEIFVKNM (GGL27), was enhanced in human plasma and largely abolished in heat-inactivated plasma, a phenomenon linked to generation of antimicrobial C3a and activation of the classic pathway of complement activation. Furthermore, GGL27 displayed anti-endotoxic effects in vitro and in vivo in a mouse model of LPS shock. Importantly, TFPI was found to be expressed in the basal layers of normal epidermis, and was markedly up-regulated in acute skin wounds as well as wound edges of chronic leg ulcers. Furthermore, C-terminal fragments of TFPI were associated with bacteria present in human chronic leg ulcers. These findings suggest a new role for TFPI in cutaneous defense against infections.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title32-vol6/pdf/CFR-2010-title32-vol6-sec842-37.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title32-vol6/pdf/CFR-2010-title32-vol6-sec842-37.pdf"><span>32 CFR 842.37 - Definitions.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-07-01</p> <p>... for international shipments. (c) Military Traffic Management Command (MTMC). The Department of Defense management agency for military traffic, land transportation, and common user ocean terminals. Among other... service responsibility for MTMC. (d) Regional Storage Management Office (RSMO). The MTMC office...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA471733','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA471733"><span>Air and Space Operations Center (AOC) Facility Design Guidelines: A Human Factors Engineering Perspective</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2006-07-01</p> <p>31 July 1995 3. Human Engineering Guide to Equipment Design, Department of Defense, Washington D.C., 1972 4. American National Standard for Human Factors Engineering of Visual Display Terminal Workstations , ANSI</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24352931','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24352931"><span>Internal radiation exposure of Ground Self-Defense Force members involved in the management of the Fukushima Nuclear Power Plant disaster.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Naoi, Yutaka; Fujikawa, Akira; Kyoto, Yukishige; Kunishima, Naoaki; Ono, Masahiro; Watanabe, Yukie</p> <p>2013-01-01</p> <p>When the Great East Japan Earthquake occurred on March 11, 2011, the Ground Self-Defense Force (GSDF) was dispatched nationally to Northeast area in Japan. The highly trained GSDF members were simultaneously assigned to various missions for the Fukushima Nuclear Power Plants disaster. The missions of GSDF terminated on August 31, 2011. Special medical examinations were conducted for the members as they returned to each military unit. GSDF members who were assigned to the nuclear power plant were at risk of radiation exposure; therefore, pocket dosimeters were used to assess external radiation exposure. A few months after the mission was terminated, measurements of internal radiation exposure were performed. This is the first report of the internal exposure of GSDF members who worked in the restricted radiation contamination area. Here, we report the amounts of internal and external exposure of and the equipment used by the GSDF members.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMNH13A0098S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMNH13A0098S"><span>Scenario-Based Case Study Analysis of Asteroid Mitigation in the Short Response Time Regime</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Seery, B.; Greenaugh, K. C.</p> <p>2017-12-01</p> <p>Asteroid impact on Earth is a rare but inevitable occurrence, with potentially cataclysmic consequences. If a pending impact is discovered, mitigation options include civil-defense preparations as well as missions to deflect the asteroid and/or robustly disrupt and disperse it to an extent that only a negligible fraction remains on a threatening path (National Research Council's "Defending the Planet," 2010). If discovered with sufficient warning time, a kinetic impactor can deflect smaller objects, but response delays can rule out the option. If a body is too large to deflect by kinetic impactor, or the time for response is insufficient, deflection or disruption can be achieved with a nuclear device. The use of nuclear ablation is considered within the context of current capabilities, requiring no need for nuclear testing. Existing, well-understood devices are sufficient for the largest known Potentially Hazardous Objects (PHOs). The National Aeronautics and Space Administration/Goddard Space Flight Center and the Department of Energy/National Nuclear Security Administration are collaborating to determine the critical characterization issues that define the boundaries for the asteroid-deflection options. Drawing from such work, we examine the timeline for a deflection mission, and how to provide the best opportunity for an impactor to suffice by minimizing the response time. This integrated problem considers the physical process of the deflection method (impact or ablation), along with the spacecraft, launch capability, risk analysis, and the available intercept flight trajectories. Our joint DOE/NASA team has conducted case study analysis of three distinctly different PHOs, on a hypothetical earth impacting trajectory. The size of the design reference bodies ranges from 100 - 500 meters in diameter, with varying physical parameters such as composition, spin state, and metallicity, to name a few. We assemble the design reference of the small body in question using known values for key parameters and expert elicitation to make educated guesses on the unknown parameters, including an estimate of the overall uncertainties in those values. Our scenario-based systems approach includes 2-D and 3-D physics-based modeling and simulations.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA217529','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA217529"><span>Department of Defense Noncombatant Evacuation Operations in the Federal Republic of Germany: Time for Tough Decisions</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1989-05-01</p> <p>taxiing to the passenger terminal; and in a few minutes 364 airmen, soldiers, and sailors coming from McGuire AFB, New Jersey, will begin to debark and...tomorrow will be bewildering, complex, fluid, and incredibly violent. The technology will be ultramodern; the psychological stresses on soldiers, as...34 Europe Without Defense? 48 Hours That Could Change the Face of the World. New York: Pergamon Press, 1979. Coffey, Kenneth J., Dr. "Defending Europe</p> </li> <li> <p><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"><span>Architecture for Mitigating Short-Term Warning Cosmic Threats: READI Project</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nambiar, Shrrirup P.; Hussein, Alaa; Silva-Martinez, Jackelynne; Reinert, Jessica; Gonzalez, Fernando</p> <p>2016-01-01</p> <p>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).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017Icar..297..149S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017Icar..297..149S"><span>Asteroid mass estimation using Markov-chain Monte Carlo</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Siltala, Lauri; Granvik, Mikael</p> <p>2017-11-01</p> <p>Estimates for asteroid masses are based on their gravitational perturbations on the orbits of other objects such as Mars, spacecraft, or other asteroids and/or their satellites. In the case of asteroid-asteroid perturbations, this leads to an inverse problem in at least 13 dimensions where the aim is to derive the mass of the perturbing asteroid(s) and six orbital elements for both the perturbing asteroid(s) and the test asteroid(s) based on astrometric observations. We have developed and implemented three different mass estimation algorithms utilizing asteroid-asteroid perturbations: the very rough 'marching' approximation, in which the asteroids' orbital elements are not fitted, thereby reducing the problem to a one-dimensional estimation of the mass, an implementation of the Nelder-Mead simplex method, and most significantly, a Markov-chain Monte Carlo (MCMC) approach. We describe each of these algorithms with particular focus on the MCMC algorithm, and present example results using both synthetic and real data. Our results agree with the published mass estimates, but suggest that the published uncertainties may be misleading as a consequence of using linearized mass-estimation methods. Finally, we discuss remaining challenges with the algorithms as well as future plans.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AcAau.130...84A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AcAau.130...84A"><span>Self-organizing control strategy for asteroid intelligent detection swarm based on attraction and repulsion</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>An, Meiyan; Wang, Zhaokui; Zhang, Yulin</p> <p>2017-01-01</p> <p>The self-organizing control strategy for asteroid intelligent detection swarm, which is considered as a space application instance of intelligent swarm, is developed. The leader-follower model for the asteroid intelligent detection swarm is established, and the further analysis is conducted for massive asteroid and small asteroid. For a massive asteroid, the leader spacecraft flies under the gravity field of the asteroid. For a small asteroid, the asteroid gravity is negligible, and a trajectory planning method is proposed based on elliptic cavity virtual potential field. The self-organizing control strategy for the follower spacecraft is developed based on a mechanism of velocity planning and velocity tracking. The simulation results show that the self-organizing control strategy is valid for both massive asteroid and small asteroid, and the exploration swarm forms a stable configuration.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150011478','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150011478"><span>BILLIARDS: Baseline Instrumented Lithology Lander, Inspector and Asteroid Redirection Demonstration System</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Marcus, Matthew; Sloane, Joshua; Ortiz, Oliver; Barbee, Brent</p> <p>2015-01-01</p> <p>BILLIARDS Baseline Instrumented Lithology Lander, Inspector, and Asteroid Redirection Demonstration System Proposed demonstration mission for Billiard-Ball concept Select asteroid pair with natural close approach to minimize cost and complexity Primary Objectives Rendezvous with a small (10m), near Earth (alpha) asteroid Maneuver the alpha asteroid to a collision with a 100m (beta) asteroid Produce a detectable deflection or disruption of the beta asteroid Secondary objectives Contribute knowledge of asteroid composition and characteristics Contribute knowledge of small-body formation Opportunity for international collaboration</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930034913&hterms=Buffer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DBuffer','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930034913&hterms=Buffer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DBuffer"><span>Explosive volcanism and the graphite-oxygen fugacity buffer on the parent asteroid(s) of the ureilite meteorites</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Warren, Paul H.; Kallemeyn, Gregory W.</p> <p>1992-01-01</p> <p>A new model of the production of the uniformly low plagioclase and Al contents of ureilites is proposed. It is argued that those contents are consequences of widespread explosive volcanism during the evolution of the parent asteroid(s). It is noted that the great abundance of graphite on the ureilite asteroid(s) made them ideal sites for explosive volcanism driven by oxidation of graphite in partial melts ascending within the asteroid(s).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890007296','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890007296"><span>Asteroid team</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Matson, D. L.</p> <p>1988-01-01</p> <p>The purpose of this task is to support asteroid research and the operation of an Asteroid Team within the Earth and Space Sciences Division at the Jet Propulsion Laboratory (JPL). The Asteroid Team carries out original research on asteroids in order to discover, better characterize and define asteroid properties. This information is needed for the planning and design of NASA asteroid flyby and rendezvous missions. The asteroid Team also provides scientific and technical advice to NASA and JPL on asteroid related programs. Work on asteroid classification continued and the discovery of two Earth-approaching M asteroids was published. In the asteroid photometry program researchers obtained N or Q photometry for more than 50 asteroids, including the two M-earth-crossers. Compositional analysis of infrared spectra (0.8 to 2.6 micrometer) of asteroids is continuing. Over the next year the work on asteroid classification and composition will continue with the analysis of the 60 reduced infrared spectra which we now have at hand. The radiometry program will continue with the reduction of the N and Q bandpass data for the 57 asteroids in order to obtain albedos and diameters. This year the emphasis will shift to IRAS follow-up observations; which includes objects not observed by IRAS and objects with poor or peculiar IRAS data. As in previous year, we plan to give top priority to any opportunities for observing near-Earth asteroids and the support (through radiometric lightcurve observations from the IRTF) of any stellar occultations by asteroids for which occultation observation expeditions are fielded. Support of preparing of IRAS data for publication and of D. Matson for his participation in the NASA Planetary Astronomy Management and Operations Working Group will continue.</p> </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"><span>14</span></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><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <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"><span>15</span></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> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1991fsa..workQ....Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1991fsa..workQ....Y"><span>International Asteroid Mission (IAM)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yamaguchi, Ryuuji</p> <p>1991-07-01</p> <p>International Asteroid Mission (IAM) is a program aimed at developing resources of asteroids abundantly existing near the earth. This report describes the research results of design project of the International Space University (ISU) held in 1990 at Tront-York University. ISU research and asteroid survey results, and the manned asteroid mining mission are outlined. Classification of asteroids existing near the earth and asteroid resource processing and use analyses are conducted. Asteroid selection flow charts are introduced, and the 1982HR-Orpheus is selected as a candidate asteroid because it takes an approaching orbit toward the earth, requires small delta V, and possesses abundant carbonaceous chondrites. Characteristics of 1982HR-Orpheus are presented. Mission requirements, mission outlines, transportation systems, and mining and processing systems for manned asteroid mining missions are presented.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA462163','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA462163"><span>Novel Pathways of Nitroaromatic Metabolism: Hydroxylamine Formation, Reactivity and Potential for Ring Fission for Destruction of TNT-CU1214</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2005-08-15</p> <p>phase was terminated when HPLC analysis showed that the initial TNT was in the form of DHA6NT and aminophenols , products that have been reported...terminated when HPLC analysis showed that the initial TNT was in the form of DHA6NT and aminophenols , products that have been reported previously (2...Department of Defense HPLC High Performance Liquid Chromatography IPTG Isopropyl-β-D-1-thiogalactopyranoside LB Luria-Bertani Broth NB Nitrobenzene</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA618545','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA618545"><span>A Potent Vector: Assessing Chinese Cruise Missile Developments</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2014-01-01</p> <p>altitude of 7 meters and perform terminal maneuvers to reduce the target’s point defense systems effectiveness. The Sunburn is reported to have a...it combines a subsonic, low-altitude ap- proach with a supersonic terminal attack conducted by a separating sprint vehicle. The 3M54E’s cruise...and Yuan 101 sea-skimming sprint vehicle that travels the last 20 km to the target at a speed of Mach 2.9. The 3M54E ASCM has a 200- kg semi-armor</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/6511183','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/6511183"><span>The termination phase of psychoanalysis in a narcissistic personality.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Warnes, H</p> <p></p> <p>This paper describes a patient whose termination phase of analysis activated an intense mourning reaction that helped to overcome the stalemate of therapy. After I attempted to demonstrate how her narcissistic armouring yielded when the termination of analysis was agreed upon, the psychological reenactment of a split off (disavowed) trauma of an early loss (her father) and the failure of essential attributes in maternal care became manifested behind her narcissistic defenses. The reconstruction of these events was possible during the process of mourning. At the termination phase she behaved as if she "had lost the war"; from the point of view of her masochism it was a Pyrrhic victory, "a victory through defeat". Contrary to mother, I let her go but then she refused to go, which created a situation that activated a profound mourning reaction leading to important structural changes. A review of the pertinent psychoanalytic literature on termination along with clinical material derived from the termination phase of a patient with a narcissistic personality is presented.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2013-05-07/pdf/2013-10955.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2013-05-07/pdf/2013-10955.pdf"><span>78 FR 26518 - Federal Acquisition Regulation; Government Property</span></a></p> <p><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></p> <p></p> <p>2013-05-07</p> <p>... DEPARTMENT OF DEFENSE GENERAL SERVICES ADMINISTRATION NATIONAL AERONAUTICS AND SPACE ADMINISTRATION 48 CFR Part 52 Federal Acquisition Regulation; Government Property CFR Correction In Title 48 of... Termination for Convenience of the Government (Fixed-Price). * * * * * (i) The cost principles and procedures...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title48-vol3/pdf/CFR-2010-title48-vol3-sec239-7411.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title48-vol3/pdf/CFR-2010-title48-vol3-sec239-7411.pdf"><span>48 CFR 239.7411 - Contract clauses.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-10-01</p> <p>... OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING ACQUISITION OF INFORMATION TECHNOLOGY Telecommunications..., Charges, and Services; (4) 252.239-7006, Tariff Information; (5) 252.239-7007, Cancellation or Termination..., Continuation of Communication Service Authorizations, as appropriate, and insert in paragraph (a) of the clause...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title48-vol3/pdf/CFR-2010-title48-vol3-sec241-202.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title48-vol3/pdf/CFR-2010-title48-vol3-sec241-202.pdf"><span>48 CFR 241.202 - Procedures.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-10-01</p> <p>... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Procedures. 241.202 Section 241.202 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT... connection charge. (ii) Termination liability. Use when an obligation is necessary to secure the required...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title48-vol3/pdf/CFR-2014-title48-vol3-sec241-202.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title48-vol3/pdf/CFR-2014-title48-vol3-sec241-202.pdf"><span>48 CFR 241.202 - Procedures.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-10-01</p> <p>... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false Procedures. 241.202 Section 241.202 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT... connection charge. (ii) Termination liability. Use when an obligation is necessary to secure the required...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title48-vol3/pdf/CFR-2012-title48-vol3-sec241-202.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title48-vol3/pdf/CFR-2012-title48-vol3-sec241-202.pdf"><span>48 CFR 241.202 - Procedures.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-10-01</p> <p>... 48 Federal Acquisition Regulations System 3 2012-10-01 2012-10-01 false Procedures. 241.202 Section 241.202 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT... connection charge. (ii) Termination liability. Use when an obligation is necessary to secure the required...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title48-vol3/pdf/CFR-2011-title48-vol3-sec241-202.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title48-vol3/pdf/CFR-2011-title48-vol3-sec241-202.pdf"><span>48 CFR 241.202 - Procedures.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-10-01</p> <p>... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Procedures. 241.202 Section 241.202 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT... connection charge. (ii) Termination liability. Use when an obligation is necessary to secure the required...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title48-vol3/pdf/CFR-2013-title48-vol3-sec241-202.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title48-vol3/pdf/CFR-2013-title48-vol3-sec241-202.pdf"><span>48 CFR 241.202 - Procedures.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-10-01</p> <p>... 48 Federal Acquisition Regulations System 3 2013-10-01 2013-10-01 false Procedures. 241.202 Section 241.202 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT... connection charge. (ii) Termination liability. Use when an obligation is necessary to secure the required...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2011-04-11/pdf/2011-8331.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2011-04-11/pdf/2011-8331.pdf"><span>76 FR 19993 - Granting of Request for Early Termination of the Waiting Period Under the Premerger Notification...</span></a></p> <p><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></p> <p></p> <p>2011-04-11</p> <p>... 03/23/2011 20110137 G Amazon.com , Inc.; Quidsi, Inc.; Amazon.com , Inc. 20110603 G Ares Corporate Opportunities Fund III, L.P.; Global Defense Technology & Systems, Inc.; Ares Corporate Opportunities Fund III...</p> </li> <li> <p><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"><span>Planetary Defense: Options for Deflection of Near Earth Objects</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Adams, R. B.; Statham, G.; Hopkins, R.; Chapman, J.; White, S.; Bonometti, J.; Alexander, R.; Fincher, S.; Polsgrove, T.; Kalkstein, M.</p> <p>2003-01-01</p> <p>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.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EPSC...11..184K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EPSC...11..184K"><span>The Asteroid Impact Mission - Deflection Demonstration (AIM - D2)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Küppers, M.; Michel, P.; Carnelli, I.</p> <p>2017-09-01</p> <p>The Asteroid Impact Mission (AIM) is ESA's contribution to the international Asteroid Impact Deflection Assessment (AIDA) cooperation, targeting the demonstration of deflection of a hazardous near-earth asteroid. AIM will also be the first in-depth investigation of a binary asteroid and make measurements that are relevant for the preparation of asteroid resource utilisation. AIM is foreseen to rendezvous with the binary near-Earth asteroid (65803) Didymos and to observe the system before, during, and after the impact of NASA's Double Asteroid Redirection Test (DART) spacecraft. Here we describe the observations to be done by the simplified version Asteroid Impact Mission - Deflection Demonstration (AIM-D2) and show that most of the original AIM objectives can still be achieved.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170003296','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170003296"><span>Project RAMA: Reconstructing Asteroids Into Mechanical Automata</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dunn, Jason; Fagin, Max; Snyder, Michael; Joyce, Eric</p> <p>2017-01-01</p> <p>Many interesting ideas have been conceived for building space-based infrastructure in cislunar space. From O'Neill's space colonies, to solar power satellite farms, and even prospecting retrieved near earth asteroids. In all the scenarios, one thing remained fixed - the need for space resources at the outpost. To satisfy this need, O'Neill suggested an electromagnetic railgun to deliver resources from the lunar surface, while NASA's Asteroid Redirect Mission called for a solar electric tug to deliver asteroid materials from interplanetary space. At Made In Space, we propose an entirely new concept. One which is scalable, cost effective, and ensures that the abundant material wealth of the inner solar system becomes readily available to humankind in a nearly automated fashion. We propose the RAMA architecture, which turns asteroids into self-contained spacecraft capable of moving themselves back to cislunar space. The RAMA architecture is just as capable of transporting conventional-sized asteroids on the 10-meter length scale as transporting asteroids 100 meters or larger, making it the most versatile asteroid retrieval architecture in terms of retrieved-mass capability. This report describes the results of the Phase I study funded by the NASA NIAC program for Made In Space to establish the concept feasibility of using space manufacturing to convert asteroids into autonomous, mechanical spacecraft. Project RAMA, Reconstituting Asteroids into Mechanical Automata, is designed to leverage the future advances of additive manufacturing (AM), in-situ resource utilization (ISRU) and in-situ manufacturing (ISM) to realize enormous efficiencies in repeated asteroid redirect missions. A team of engineers at Made In Space performed the study work with consultation from the asteroid mining industry, academia, and NASA. Previous studies for asteroid retrieval have been constrained to studying only asteroids that are both large enough to be discovered, and small enough to be captured and transported using Earth-launched propulsion technology. Project RAMA is not forced into this constraint. The mission concept studied involved transporting a much larger approximately 50-meter asteroid to cislunar space. Demonstration of transport of a 50-meter-class asteroid has several ground-breaking advantages. First, the returned material is of an industrial, rather than just scientific, quantity (greater than 10,000 tonnes versus approximately10s of tonnes). Second, the "useless" material in the asteroid is gathered and expended as part of the asteroid's propulsion system, allowing the returned asteroid to be considerably "purer" than a conventional asteroid retrieval mission. Third, the infrastructure used to convert and return the asteroid is reusable, and capable of continually returning asteroids to cislunar space.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013DPS....4530108R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013DPS....4530108R"><span>Effects of YORP-induced rotational fission on the small size end of the Main Belt asteroid size distribution</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rossi, Alessandro; Jacobson, S.; Marzari, F.; Scheeres, D.; Davis, D. R.</p> <p>2013-10-01</p> <p>From the results of a comprehensive asteroid population evolution model, we conclude that the YORP-induced rotational fission hypothesis has strong repercussions for the small size end of the Main Belt asteroid size frequency distribution. These results are consistent with observed asteroid population statistics. The foundation of this model is the asteroid rotation model of Marzari et al. (2011), which incorporates both the YORP effect and collisional evolution. This work adds to that model the rotational fission hypothesis (i.e. when the rotation rate exceeds a critical value, erosion and binary formation occur). The YORP effect timescale for large asteroids with diameters D > ~6 km is longer than the collision timescale in the Main Belt, thus the frequency of large asteroids is determined by a collisional equilibrium (e.g. Bottke 2005), but for small asteroids with diameters D < ~6 km, the asteroid population evolution model confirms that YORP-induced rotational fission destroys small asteroids more frequently than collisions. Therefore, the frequency of these small asteroids is determined by an equilibrium between the creation of new asteroids out of the impact debris of larger asteroids and the destruction of these asteroids by YORP-induced rotational fission. By introducing a new source of destruction that varies strongly with size, YORP-induced rotational fission alters the slope of the size frequency distribution. Using the outputs of the asteroid population evolution model and a 1-D collision evolution model, we can generate this new size frequency distribution and it matches the change in slope observed by the SKADS survey (Gladman 2009). This agreement is achieved with both an accretional power-law or a truncated “Asteroids were Born Big” size frequency distribution (Weidenschilling 2010, Morbidelli 2009).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20090008495&hterms=Research+power&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DResearch%2Bpower','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20090008495&hterms=Research+power&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DResearch%2Bpower"><span>Reliability Block Diagram (RBD) Analysis of NASA Dryden Flight Research Center (DFRC) Flight Termination System and Power Supply</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Morehouse, Dennis V.</p> <p>2006-01-01</p> <p>In order to perform public risk analyses for vehicles containing Flight Termination Systems (FTS), it is necessary for the analyst to know the reliability of each of the components of the FTS. These systems are typically divided into two segments; a transmitter system and associated equipment, typically in a ground station or on a support aircraft, and a receiver system and associated equipment on the target vehicle. This analysis attempts to analyze the reliability of the NASA DFRC flight termination system ground transmitter segment for use in the larger risk analysis and to compare the results against two established Department of Defense availability standards for such equipment.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950013159','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950013159"><span>Near-Earth Asteroid Returned Sample (NEARS)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shoemaker, Eugene M.; Cheng, Andrew F.</p> <p>1994-01-01</p> <p>The concept of the Near-Earth Asteroid Returned Sample (NEARS) mission is to return to Earth 10-100 g from each of four to six sites on a near-Earth asteroid and to perform global characterization of the asteroid and measure mass, volume, and density to ten percent. The target asteroid for the mission is 4660 Nereus, probably a primitive C-type asteroid, with the alternate target being 1989ML, an extremely accessible asteroid of unknown type. Launch dates will be 1998, 2000, 2002, and 2004 on the Delta II-7925 launch vehicle. The mission objectives are three-fold. (1) Provide first direct and detailed petrological, chemical, age, and isotopic characterization of a near-Earth asteroid and relate it to terrestrial, lunar, and meteoritic materials. (2) Sample the asteroid regolith and characterize any exotic fragments. (3) Identify heterogeneity in the asteroid's isotopic properties, age, and elemental chemistry.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017BTSNU..56...39K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017BTSNU..56...39K"><span>Asteroid size distributions for the main belt and for asteroid families</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kazantzev, A.; Kazantzeva, L.</p> <p>2017-12-01</p> <p>The asteroid-size distribution for he Eos family was constructed. The WISE database containing the albedo p and the size D of over 80,000 asteroids was used. The b parameter of the power-law dependence has a minimum at some average values of the asteroid size of the family. A similar dependence b(D) exists for the whole asteroid belt. An assumption on the possible similarity of the formation mechanisms of the asteroid belt as a whole and separate families is made.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E3757Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E3757Z"><span>Flyght Dynamics of Artificial Satellite of the Minor Asteroid</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zakharov, Alexander; Eismont, Natan; Ledkov, Anton; Simonov, Alexander; Pol, Vadim</p> <p></p> <p>During last years the scientific interest to the asteroid is constantly growing. It may be explained by different reasons. One of the most important from them is confirmation of the fact that the asteroids present the real hazard to the Earth. The Chelyabinsk event demonstrates strong in support of this statement. Besides, the asteroids exploration promises to supply new data for understanding of the solar system origin and evolution. And the projects aimed to reach this goal have begun from the NASA NEAR mission to Eros. It was the first one when the spacecraft was landed on the surface of the asteroid. The other successive mission was fulfilled by JAXA with Hayabusa spacecraft which has returned to the Earth soil samples of Itokawa asteroid. In the nearest future the mission to RQ 36 asteroid is planned supposing landing and soil samples return. Unavoidable phase of such missions is the spacecraft flight in vicinity of the target asteroid, for example on the asteroid satellite orbit. It should be mentioned that quite visible number of asteroids has geometric form which is far from being sphere. Accordingly the gravity field of such asteroid cannot be presented as the one close to sphere. The problem is that prior to the mission to the asteroid one cannot receive good enough knowledge of its gravity field and even its gravity field constant. In the paper the flight dynamics problem of spacecraft moving along asteroid satellite orbit is explored. It is supposed that the asteroid is comparatively small with diameter (maximum size) about 300 m, like Apophis asteroid has, or less. To approximate the gravity field of asteroid the last is considered as totality of mass points. We assume such approach as more simple and effective as compared with the commonly accepted use of Legendre polynomial expansion. Different orbits near asteroid are analyzed with the sets of orbital parameters determining the size of orbit, its shape and position with respect to the Sun. The goal of this analysis is to understand what initial orbital parameters deliver stability of the orbit in terms of avoiding the collision with the asteroid surface. The orbital heights are calculated which allow to consider the asteroid gravity field as close to the spherical one de-pending on the shape of asteroid. Also maneuvers are estimated necessary for keeping the spacecraft on asteroid satellite orbit and for changing orbital parameters. Taking into account that gravity field parameters of the target asteroids may have pure accuracy it is supposed that spacecraft starts its motion in vicinity of the asteroid from the high enough orbit and then after processing of the tracking data maneuvers are executed to decrease spacecraft altitude. Methods of this procedure optimization are explored.</p> </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"><span>15</span></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><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <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"><span>16</span></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> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA15627.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA15627.html"><span>Edge-on View of Near-Earth Asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2012-05-16</p> <p>NEOWISE, the asteroid-hunting portion of NASA WISE mission, illustrates the differences between orbits of a typical near-Earth asteroid blue and a potentially hazardous asteroid, or PHA orange. PHAs are a subset of the near-Earth asteroids NEAs.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMNH13A0104B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMNH13A0104B"><span>Energetic Techniques For Planetary Defense</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barbee, B.; Bambacus, M.; Bruck Syal, M.; Greenaugh, K. C.; Leung, R. Y.; Plesko, C. S.</p> <p>2017-12-01</p> <p>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.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title10-vol1/pdf/CFR-2012-title10-vol1-sec2-4.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title10-vol1/pdf/CFR-2012-title10-vol1-sec2-4.pdf"><span>10 CFR 2.4 - Definitions.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-01-01</p> <p>... and safety or the common defense and security; security measures for the physical protection and... computer that contains the participant's name, e-mail address, and participant's digital signature, proves... inspection. It is also the place where NRC makes computer terminals available to access the Publicly...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title10-vol1/pdf/CFR-2010-title10-vol1-sec2-4.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title10-vol1/pdf/CFR-2010-title10-vol1-sec2-4.pdf"><span>10 CFR 2.4 - Definitions.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-01-01</p> <p>... and safety or the common defense and security; security measures for the physical protection and... computer that contains the participant's name, e-mail address, and participant's digital signature, proves... inspection. It is also the place where NRC makes computer terminals available to access the Publicly...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26068082','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26068082"><span>Auditory cortex controls sound-driven innate defense behaviour through corticofugal projections to inferior colliculus.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xiong, Xiaorui R; Liang, Feixue; Zingg, Brian; Ji, Xu-ying; Ibrahim, Leena A; Tao, Huizhong W; Zhang, Li I</p> <p>2015-06-11</p> <p>Defense against environmental threats is essential for animal survival. However, the neural circuits responsible for transforming unconditioned sensory stimuli and generating defensive behaviours remain largely unclear. Here, we show that corticofugal neurons in the auditory cortex (ACx) targeting the inferior colliculus (IC) mediate an innate, sound-induced flight behaviour. Optogenetic activation of these neurons, or their projection terminals in the IC, is sufficient for initiating flight responses, while the inhibition of these projections reduces sound-induced flight responses. Corticocollicular axons monosynaptically innervate neurons in the cortex of the IC (ICx), and optogenetic activation of the projections from the ICx to the dorsal periaqueductal gray is sufficient for provoking flight behaviours. Our results suggest that ACx can both amplify innate acoustic-motor responses and directly drive flight behaviours in the absence of sound input through corticocollicular projections to ICx. Such corticofugal control may be a general feature of innate defense circuits across sensory modalities.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA130650','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA130650"><span>Proceedings, Conference on the Defense Planning, Programming, and Budgeting System (PPBS): Past, Present, and Future Held at Washington, DC on 4-6 November 1982</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1982-11-06</p> <p>They are reviewed by the Deputy Chief of Staff for Installations and Logistics to de - The DC/S for manpower then goes on to a termine the logistica ...analyses have manages its programming process. concentrated on such innovations as the De - fense Resources Board and Defense Guidance. * Discussions of... transport that fighting force to the every student of any kind of management at all beach or into battle, then all of General would say that if you</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24660117','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24660117"><span>Chemerin regulation and role in host defense.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zabel, Brian A; Kwitniewski, Mateusz; Banas, Magdalena; Zabieglo, Katarzyna; Murzyn, Krzysztof; Cichy, Joanna</p> <p>2014-01-01</p> <p>Chemerin is a widely distributed multifunctional secreted protein implicated in immune cell migration, adipogenesis, osteoblastogenesis, angiogenesis, myogenesis, and glucose homeostasis. Chemerin message is regulated by nuclear receptor agonists, metabolic signaling proteins and intermediates, and proinflammatory cytokines. Following translation chemerin is secreted as an inactive pro-protein, and its secretion can be regulated depending on cell type. Chemerin bioactivity is largely dependent on carboxyl-terminal proteolytic processing and removal of inhibitory residues. Chemerin is abundant in human epidermis where it is well-placed to provide barrier protection. In host defense, chemerin plays dual roles as a broad spectrum antimicrobial protein and as a leukocyte attractant for macrophages, dendritic cells, and NK cells. Here we review the mechanisms underlying chemerin regulation and its function in host defense.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750009195','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750009195"><span>Small bodies and the outer planets and Appendices 1 and 2</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Davis, D. R.</p> <p>1974-01-01</p> <p>Correlations of asteroid spectral reflectivity characteristics with orbital parameters have been sought. Asteroid proper elements and extreme heliocentric distance were examined. Only general trends were noted, primarily red asteroids and asteroids with IR (.95 micron) absorption bands are concentrated toward the inner part of the belt. Also, asteroids with the pyroxene band tend to have larger proper eccentricities relative to non-banded asteroids.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014acm..conf..234J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014acm..conf..234J"><span>Both size-frequency distribution and sub-populations of the main-belt asteroid population are consistent with YORP-induced rotational fission</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jacobson, S.; Scheeres, D.; Rossi, A.; Marzari, F.; Davis, D.</p> <p>2014-07-01</p> <p>From the results of a comprehensive asteroid-population-evolution model, we conclude that the YORP-induced rotational-fission hypothesis has strong repercussions for the small size end of the main-belt asteroid size-frequency distribution and is consistent with observed asteroid-population statistics and with the observed sub-populations of binary asteroids, asteroid pairs and contact binaries. The foundation of this model is the asteroid-rotation model of Marzari et al. (2011) and Rossi et al. (2009), which incorporates both the YORP effect and collisional evolution. This work adds to that model the rotational fission hypothesis (i.e. when the rotation rate exceeds a critical value, erosion and binary formation occur; Scheeres 2007) and binary-asteroid evolution (Jacobson & Scheeres, 2011). The YORP-effect timescale for large asteroids with diameters D > ˜ 6 km is longer than the collision timescale in the main belt, thus the frequency of large asteroids is determined by a collisional equilibrium (e.g. Bottke 2005), but for small asteroids with diameters D < ˜ 6 km, the asteroid-population evolution model confirms that YORP-induced rotational fission destroys small asteroids more frequently than collisions. Therefore, the frequency of these small asteroids is determined by an equilibrium between the creation of new asteroids out of the impact debris of larger asteroids and the destruction of these asteroids by YORP-induced rotational fission. By introducing a new source of destruction that varies strongly with size, YORP-induced rotational fission alters the slope of the size-frequency distribution. Using the outputs of the asteroid-population evolution model and a 1-D collision evolution model, we can generate this new size-frequency distribution and it matches the change in slope observed by the SKADS survey (Gladman 2009). This agreement is achieved with both an accretional power-law or a truncated ''Asteroids were Born Big'' size-frequency distribution (Weidenschilling 2010, Morbidelli 2009). The binary-asteroid evolution model is highly constrained by the modeling done in Jacobson & Scheeres, and therefore the asteroid-population evolution model has only two significant free parameters: the ratio of low-to-high-mass-ratio binaries formed after rotational fission events and the mean strength of the binary YORP (BYORP) effect. Using this model, we successfully reproduce the observed small-asteroid sub-populations, which orthogonally constrain the two free parameters. We find the outcome of rotational fission most likely produces an initial mass-ratio fraction that is four to eight times as likely to produce high-mass-ratio systems as low-mass-ratio systems, which is consistent with rotational fission creating binary systems in a flat distribution with respect to mass ratio. We also find that the mean of the log-normal BYORP coefficient distribution B ≈ 10^{-2}.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920060684&hterms=round+earth&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dround%2Bearth','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920060684&hterms=round+earth&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dround%2Bearth"><span>Mission options for rendezvous with the most accessible Near-Earth Asteroid - 1989 ML</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mcadams, Jim V.</p> <p>1992-01-01</p> <p>The recent discovery of the Amor-class 1989 ML, the most accessible known asteroid for minimum-energy rendezvous missions, has expedited the search for frequent, low-cost Near-Earth Asteroid rendezvous and round-trip missions. This paper identifies trajectory characteristics and assesses mass performance for low Delta V ballistic rendezvous opportunities to 1989 ML during the period 1996-2010. This asteroid also offers occasional unique extended mission opportunities, such as the lowest known Delta V requirement for any asteroid sample return mission as well as pre-rendezvous asteroid flyby and post-rendezvous comet flyby opportunities requiring less than 5.25 km/sec total Delta V. This paper also briefly comments concerning mission opportunities for asteroid 1991 JW, which recently replaced other known asteroids as the most accessible Near-Earth Asteroid for fast rendezvous and round-trip missions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19880013459','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19880013459"><span>Speckle interferometry of asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Drummond, Jack</p> <p>1988-01-01</p> <p>This final report for NASA Contract NAGw-867 consists of abstracts of the first three papers in a series of four appearing in Icarus that were funded by the preceding contract NAGw-224: (1) Speckle Interferometry of Asteroids I. 433 Eros; (2) Speckle Interferometry of Asteroids II. 532 Herculina; (3) Speckle Interferometry of Asteroids III. 511 Davida and its Photometry; and the fourth abstract attributed to NAGw-867, (4) Speckle Interferometry of Asteroids IV. Reconstructed images of 4 Vesta; and a review of the results from the asteroid interferometry program at Steward Observatory prepared for the Asteroids II book, (5) Speckle Interferometry of Asteroids. Two papers on asteroids, indirectly related to speckle interferometry, were written in part under NAGw-867. One is in press and its abstract is included here: Photometric Geodesy of Main-Belt Asteroids. II. Analysis of Lightcurves for Poles, Periods and Shapes; and the other paper, Triaxial Ellipsoid Dimensions and Rotational Pole of 2 Pallas from Two Stellar Occultations, is included in full.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMIN33B1043H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMIN33B1043H"><span>NPOESS Field Terminal Updates</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Heckmann, G.; Route, G.</p> <p>2009-12-01</p> <p>The National Oceanic and Atmospheric Administration (NOAA), Department of Defense (DoD), and National Aeronautics and Space Administration (NASA) are jointly acquiring the next-generation weather and environmental satellite system; the National Polar-orbiting Operational Environmental Satellite System (NPOESS). NPOESS replaces the current Polar-orbiting Operational Environmental Satellites (POES) managed by NOAA and the Defense Meteorological Satellite Program (DMSP) managed by the DoD. The NPOESS satellites carry a suite of sensors that collect meteorological, oceanographic, climatological, and solar-geophysical observations of the earth, atmosphere, and space. The ground data processing segment for NPOESS is the Interface Data Processing Segment (IDPS), developed by Raytheon Intelligence and Information Systems. The IDPS processes NPOESS satellite data to provide environmental data products (aka, Environmental Data Records or EDRs) to NOAA and DoD processing centers operated by the United States government. The IDPS will process EDRs beginning with the NPOESS Preparatory Project (NPP) and continuing through the lifetime of the NPOESS system. IDPS also provides the software and requirements for the Field Terminal Segment (FTS). NPOESS provides support to deployed field terminals by providing mission data in the Low Rate and High Rate downlinks (LRD/HRD), mission support data needed to generate EDRs and decryption keys needed to decrypt mission data during Selective data Encryption (SDE). Mission support data consists of globally relevant data, geographically constrained data, and two line element sets. NPOESS provides these mission support data via the Internet accessible Mission Support Data Server and HRD/LRD downlinks. This presentation will illustrate and describe the NPOESS capabilities in support of Field Terminal users. This discussion will include the mission support data available to Field Terminal users, content of the direct broadcast HRD and LRD downlinks identifying differences between the direct broadcast downlinks including the variability of the LRD downlink and NPOESS management and distribution of decryption keys to approved field terminals using Public Key Infrastructure (PKI) AES standard with 256 bit encryption and elliptical curve cryptography.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4832401S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4832401S"><span>Asteroid mass estimation using Markov-Chain Monte Carlo techniques</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Siltala, Lauri; Granvik, Mikael</p> <p>2016-10-01</p> <p>Estimates for asteroid masses are based on their gravitational perturbations on the orbits of other objects such as Mars, spacecraft, or other asteroids and/or their satellites. In the case of asteroid-asteroid perturbations, this leads to a 13-dimensional inverse problem where the aim is to derive the mass of the perturbing asteroid and six orbital elements for both the perturbing asteroid and the test asteroid using astrometric observations. We have developed and implemented three different mass estimation algorithms utilizing asteroid-asteroid perturbations into the OpenOrb asteroid-orbit-computation software: the very rough 'marching' approximation, in which the asteroid orbits are fixed at a given epoch, reducing the problem to a one-dimensional estimation of the mass, an implementation of the Nelder-Mead simplex method, and most significantly, a Markov-Chain Monte Carlo (MCMC) approach. We will introduce each of these algorithms with particular focus on the MCMC algorithm, and present example results for both synthetic and real data. Our results agree with the published mass estimates, but suggest that the published uncertainties may be misleading as a consequence of using linearized mass-estimation methods. Finally, we discuss remaining challenges with the algorithms as well as future plans, particularly in connection with ESA's Gaia mission.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1991rnes.nasa...14D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1991rnes.nasa...14D"><span>Asteroid/meteorite streams</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Drummond, J.</p> <p></p> <p>The independent discovery of the same three streams (named alpha, beta, and gamma) among 139 Earth approaching asteroids and among 89 meteorite producing fireballs presents the possibility of matching specific meteorites to specific asteroids, or at least to asteroids in the same stream and, therefore, presumably of the same composition. Although perhaps of limited practical value, the three meteorites with known orbits are all ordinary chondrites. To identify, in general, the taxonomic type of the parent asteroid, however, would be of great scientific interest since these most abundant meteorite types cannot be unambiguously spectrally matched to an asteroid type. The H5 Pribram meteorite and asteroid 4486 (unclassified) are not part of a stream, but travel in fairly similar orbits. The LL5 Innisfree meteorite is orbitally similar to asteroid 1989DA (unclassified), and both are members of a fourth stream (delta) defined by five meteorite-dropping fireballs and this one asteroid. The H5 Lost City meteorite is orbitally similar to 1980AA (S type), which is a member of stream gamma defined by four asteroids and four fireballs. Another asteroid in this stream is classified as an S type, another is QU, and the fourth is unclassified. This stream suggests that ordinary chondrites should be associated with S (and/or Q) asteroids. Two of the known four V type asteroids belong to another stream, beta, defined by five asteroids and four meteorite-dropping (but unrecovered) fireballs, making it the most probable source of the eucrites. The final stream, alpha, defined by five asteroids and three fireballs is of unknown composition since no meteorites have been recovered and only one asteroid has an ambiguous classification of QRS. If this stream, or any other as yet undiscovered ones, were found to be composed of a more practical material (e.g., water or metalrich), then recovery of the associated meteorites would provide an opportunity for in-hand analysis of a potential near-Earth resource.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910016724&hterms=innisfree&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dinnisfree','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910016724&hterms=innisfree&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dinnisfree"><span>Asteroid/meteorite streams</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Drummond, J.</p> <p>1991-01-01</p> <p>The independent discovery of the same three streams (named alpha, beta, and gamma) among 139 Earth approaching asteroids and among 89 meteorite producing fireballs presents the possibility of matching specific meteorites to specific asteroids, or at least to asteroids in the same stream and, therefore, presumably of the same composition. Although perhaps of limited practical value, the three meteorites with known orbits are all ordinary chondrites. To identify, in general, the taxonomic type of the parent asteroid, however, would be of great scientific interest since these most abundant meteorite types cannot be unambiguously spectrally matched to an asteroid type. The H5 Pribram meteorite and asteroid 4486 (unclassified) are not part of a stream, but travel in fairly similar orbits. The LL5 Innisfree meteorite is orbitally similar to asteroid 1989DA (unclassified), and both are members of a fourth stream (delta) defined by five meteorite-dropping fireballs and this one asteroid. The H5 Lost City meteorite is orbitally similar to 1980AA (S type), which is a member of stream gamma defined by four asteroids and four fireballs. Another asteroid in this stream is classified as an S type, another is QU, and the fourth is unclassified. This stream suggests that ordinary chondrites should be associated with S (and/or Q) asteroids. Two of the known four V type asteroids belong to another stream, beta, defined by five asteroids and four meteorite-dropping (but unrecovered) fireballs, making it the most probable source of the eucrites. The final stream, alpha, defined by five asteroids and three fireballs is of unknown composition since no meteorites have been recovered and only one asteroid has an ambiguous classification of QRS. If this stream, or any other as yet undiscovered ones, were found to be composed of a more practical material (e.g., water or metalrich), then recovery of the associated meteorites would provide an opportunity for in-hand analysis of a potential near-Earth resource.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730004163','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730004163"><span>Asteroid selection for mission opportunities. Appendix: Asteroid data sheets</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1972-01-01</p> <p>The characteristics of asteroids selected as possible space mission objectives are presented. The asteroids are described according to: (1) magnitude, (2) spectral reflectivity; (3) phase factors, (4) polarization, (5) light curve, and (6) physical parameters. The data are tabulated on specific formats for each asteroid considered.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19780021071','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19780021071"><span>Asteroid surface mineralogy: Evidence from earth-based telescope observations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mccord, T. B.</p> <p>1978-01-01</p> <p>The interpretation of asteroid reflectance spectrophotometry in terms of mineralogical types gives inferred mineral assemblages for about 60 asteroids. Asteroid surface materials are compared with similar materials that make up many meteorites. The absence of asteroids with spectra that match identically the ordinary chondrites is noted.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5916513','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5916513"><span>Footprints preserve terminal Pleistocene hunt? Human-sloth interactions in North America</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Urban, Tommy M.; Raichlen, David A.; Budka, Marcin; Reynolds, Sally C.; Love, David W.; Santucci, Vincent L.; Willey, Patrick; McDonald, H. Gregory</p> <p>2018-01-01</p> <p>Predator-prey interactions revealed by vertebrate trace fossils are extremely rare. We present footprint evidence from White Sands National Monument in New Mexico for the association of sloth and human trackways. Geologically, the sloth and human trackways were made contemporaneously, and the sloth trackways show evidence of evasion and defensive behavior when associated with human tracks. Behavioral inferences from these trackways indicate prey selection and suggest that humans were harassing, stalking, and/or hunting the now-extinct giant ground sloth in the terminal Pleistocene. PMID:29707640</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020046038&hterms=family&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dfamily','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020046038&hterms=family&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dfamily"><span>Meteoritic and Asteroidal Constraints on the Identification and Collisional Evolution of Asteroid Families</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gaffey, Michael J.; Kelley, Michael S.; Hardersen, Paul S.</p> <p>2002-01-01</p> <p>Studies of meteorites and observations of asteroids can provide important constraints on the formation and evolution of asteroid families. The iron meteorites alone require the disruption of 85 differentiated asteroids, and the potential formation of 85 families. Additional information is contained in the original extended abstract.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995PhyU...38..623P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995PhyU...38..623P"><span>REVIEWS OF TOPICAL PROBLEMS: Satellites of asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prokof'eva, Valentina V.; Tarashchuk, V. P.; Gor'kavyi, N. N.</p> <p>1995-06-01</p> <p>More than 6000 asteroids in the Solar System have now been discovered and enumerated, and about 500 of them have been investigated in detail by different methods. This rewiew gives observational evidence which indicates that no fewer than 10% of asteroids may be composed of two or more bodies. This was supported by the detection of a satellite of the asteroid Ida by the Galileo spacecraft. This discovery symbolises the change of both observational and theoretical paradigms. Space and ground observations of asteroids by modern teghniques may give extensive new data for modelling double asteroids. The analysis of problems of stability, formation and dynamics of asteroid satellites shows that their sphere of stable motion extends up to several hundred asteroid radii. The idea that the origin of the asteroid satellites may be explained in the frame of a unified accretion model of planetary satellite formation is proposed and justified.</p> </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"><span>16</span></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><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <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"><span>17</span></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> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19790070477&hterms=theory+evolution&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dtheory%2Bevolution','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19790070477&hterms=theory+evolution&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dtheory%2Bevolution"><span>Asteroid rotation. I - Tabulation and analysis of rates, pole positions and shapes. II - A theory for the collisional evolution of rotation rates</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Harris, A. W.; Burns, J. A.</p> <p>1979-01-01</p> <p>Rotation properties and shape data for 182 asteroids are compiled and analyzed, and a collisional model for the evolution of the mean rotation rate of asteroids is proposed. Tabulations of asteroid rotation rates, taxonomic types, pole positions, sizes and shapes and plots of rotation frequency and light curve amplitude against size indicate that asteroid rotational frequency increases with decreasing size for all asteroids except those of the C or S classes. Light curve data also indicate that small asteroids are more irregular in shape than large asteroids. The dispersion in rotation rates observed is well represented by a three dimensional Maxwellian distribution, suggestive of collisional encounters between asteroids. In the proposed model, the rotation rate is found to tend toward an equilibrium value, at which spin-up due to infrequent, large collisions is balanced by a drag due to the larger number of small collisions. The lower mean rotation rate of C-type asteroids is attributed to a lower means density of that class, and the increase in rotation rate with decreasing size is interpreted as indicative of a substantial population of strong asteroids.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998A%26AS..128..525P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998A%26AS..128..525P"><span>Physical studies of asteroids. XXXII. Rotation periods and UBVRI-colours for selected asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Piironen, J.; Lagerkvist, C.-I.; Erikson, A.; Oja, T.; Magnusson, P.; Festin, L.; Nathues, A.; Gaul, M.; Velichko, F.</p> <p>1998-03-01</p> <p>We present lightcurves of selected asteroids. Most of the asteroids were included to obtain refined spin periods. Enhanced periods were determined for 11 Parthenope, 306 Unitas and 372 Palma. We confirmed the spin periods of 8 Flora, 13 Egeria, 71 Niobe, 233 Asterope, 291 Alice, 409 Aspasia, 435 Ella and 512 Taurinensis. We determined also BV-colours for most of the included asteroids and UBVRI-colours for a total of 22 asteroids.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AJ....154...76B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AJ....154...76B"><span>Simultaneous Mass Determination for Gravitationally Coupled Asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baer, James; Chesley, Steven R.</p> <p>2017-08-01</p> <p>The conventional least-squares asteroid mass determination algorithm allows us to solve for the mass of a large subject asteroid that is perturbing the trajectory of a smaller test asteroid. However, this algorithm is necessarily a first approximation, ignoring the possibility that the subject asteroid may itself be perturbed by the test asteroid, or that the encounter’s precise geometry may be entangled with encounters involving other asteroids. After reviewing the conventional algorithm, we use it to calculate the masses of 30 main-belt asteroids. Compared to our previous results, we find new mass estimates for eight asteroids (11 Parthenope, 27 Euterpe, 51 Neimausa, 76 Freia, 121 Hermione, 324 Bamberga, 476 Hedwig, and 532 Herculina) and significantly more precise estimates for six others (2 Pallas, 3 Juno, 4 Vesta, 9 Metis, 16 Psyche, and 88 Thisbe). However, we also find that the conventional algorithm yields questionable results in several gravitationally coupled cases. To address such cases, we describe a new algorithm that allows the epoch state vectors of the subject asteroids to be included as solve-for parameters, allowing for the simultaneous solution of the masses and epoch state vectors of multiple subject and test asteroids. We then apply this algorithm to the same 30 main-belt asteroids and conclude that mass determinations resulting from current and future high-precision astrometric sources (such as Gaia) should conduct a thorough search for possible gravitational couplings and account for their effects.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MPBu...42....4M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MPBu...42....4M"><span>Asteroid Lightcurve Analysis at Isaac Aznar Observatory Aras De Los Olmos, Valencia, Spain</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Macias, Amadeo Aznar</p> <p>2015-01-01</p> <p>The Isaac Aznar Observatory conducts astrometric and photometric studies of asteroids. This paper contains the photometric results of four asteroids obtained from 2014 April to August. These asteroids were selected from the Collaborative Asteroid Lightcurve Link (CALL) web site: 1088 Mitaka, 2956 Yeomans, 3894 Williamcooke, and (4555) 1974QL.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AdSpR..59.1921Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AdSpR..59.1921Z"><span>Rotational and translational considerations in kinetic impact deflection of potentially hazardous asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Fei; Xu, Bo; Circi, Christian; Zhang, Lei</p> <p>2017-04-01</p> <p>Kinetic impact may be the most reliable and easily implemented method to deflect hazardous asteroids using current technology. Depending on warning time, it can be effective on asteroids with diameters of a few hundred meters. Current impact deflection research often focuses on the orbital dynamics of asteroids. In this paper, we use the ejection outcome of a general oblique impact to calculate how an asteroid's rotational and translational state changes after impact. The results demonstrate how small impactors affect the dynamical state of small asteroids having a diameter of about 100 m. According to these consequences, we propose using several small impactors to hit an asteroid continuously and gently, making the deflection mission relatively flexible. After calculating the rotational variation, we find that the rotational state, especially of slender non-porous asteroids, can be changed significantly. This gives the possibility of using multiple small impactors to mitigate a potentially hazardous asteroid by spinning it up into pieces, or to despin one for future in-situ investigation (e.g., asteroid retrieval or mining).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28954171','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28954171"><span>The last dinosaurs of Brazil: The Bauru Group and its implications for the end-Cretaceous mass extinction.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Brusatte, Stephen L; Candeiro, Carlos R A; Simbras, Felipe M</p> <p>2017-01-01</p> <p>The non-avian dinosaurs died out at the end of the Cretaceous, ~66 million years ago, after an asteroid impact. The prevailing hypothesis is that the effects of the impact suddenly killed the dinosaurs, but the poor fossil record of latest Cretaceous (Campanian-Maastrichtian) dinosaurs from outside Laurasia (and even more particularly, North America) makes it difficult to test specific extinction scenarios. Over the past few decades, a wealth of new discoveries from the Bauru Group of Brazil has revealed a unique window into the evolution of terminal Cretaceous dinosaurs from the southern continents. We review this record and demonstrate that there was a diversity of dinosaurs, of varying body sizes, diets, and ecological roles, that survived to the very end of the Cretaceous (Maastrichtian: 72-66 million years ago) in Brazil, including a core fauna of titanosaurian sauropods and abelisaurid and carcharodontosaurid theropods, along with a variety of small-to-mid-sized theropods. We argue that this pattern best fits the hypothesis that southern dinosaurs, like their northern counterparts, were still diversifying and occupying prominent roles in their ecosystems before the asteroid suddenly caused their extinction. However, this hypothesis remains to be tested with more refined paleontological and geochronological data, and we give suggestions for future work.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AdSpR..59.1304D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AdSpR..59.1304D"><span>Numerical investigation of the dynamical environment of 65803 Didymos</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dell'Elce, L.; Baresi, N.; Naidu, S. P.; Benner, L. A. M.; Scheeres, D. J.</p> <p>2017-03-01</p> <p>The Asteroid Impact & Deflection Assessment (AIDA) mission is planning to visit the Didymos binary system in 2022 in order to perform the first demonstration ever of the kinetic impact technique. Binary asteroids are an ideal target for this since the deflection of the secondary body can be accurately measured by a satellite orbiting in the system. However, these binaries offer an extremely rich dynamical environment whose accurate investigation through analytical approaches is challenging at best and requires a significant number of restrictive assumptions. For this reason, a numerical investigation of the dynamical environment in the vicinity of the Didymos system is offered in this paper. After computing various families of periodic orbits, their robustness is assessed in a high-fidelity environment consisting of the perturbed restricted full three-body problem. The results of this study suggest that several nominally stable trajectories, including the triangular libration points, should not be considered as safe as a state vector perturbation may cause the spacecraft to drift from the nominal orbit and possibly impact one of the primary bodies within a few days. Nonetheless, there exist two safe solutions, namely terminator and interior retrograde orbits. The first one is adequate for observation purposes of the entire system and for communications. The second one is more suitable to perform close investigations of the primary body.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950060229&hterms=analysis+components+main&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Danalysis%2Bcomponents%2Bmain','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950060229&hterms=analysis+components+main&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Danalysis%2Bcomponents%2Bmain"><span>Small main-belt asteroid spectroscopic survey: Initial results</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Xu, Shui; Binzel, Richard P.; Burbine, Thomas H.; Bus, Schelte J.</p> <p>1995-01-01</p> <p>The spectral characterization of small asteroids is important for understanding the evolution of their compositional and mineralogical properties. We report the results of a CCD spectroscopic survey of small main-belt asteroids which we call the Small Main-belt Asteroid Spectroscopic Survey (SMASS). Spectra of 316 asteroids were obtained, with wavelength coverage ranging from 4000 to 10000 A (0.4 to 1 micrometers). More than half of the objects in our survey have diameters less than 20 km. Survey results include the identification of the first object resembling ordinary chondrite meteorites among the main-belt asteroids (Binzel, R. P., et al, 1993) and observations of more than 20 asteroids showing basaltic achondrite spectral absorption features that strongly link Vesta as the parent body for the basaltic achondrite meteorites (Binzel, R. P., and S. Xu 1993). A potential Mars-crossing asteroid analog to ordinary chondrite meteorites (H chondrites), 2078 Nanking, is reported here. Through a principal component analysis, we have assigned classifications to the members of our sample. The majority of the small main-belt asteroids belong to S and C classes, similar to large asteroids. Our analysis shows that two new classes are justified which we label as J and O. Small asteroids display more diversity in spectral absorption features than the larger ones, which may indicate a greater variation of compositions in the small asteroid population. We found a few candidates for olivine-rich asteroids within the S class. Although the total number of olivine-rich candidates is relatively small, we present evidence suggesting that such objects are more prevalent at smaller sizes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28263649','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28263649"><span>Fostering engagement during termination: Applying attachment theory and research.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Marmarosh, Cheri L</p> <p>2017-03-01</p> <p>Therapists often struggle to determine the most important things to focus on during termination. Reviewing the treatment, identifying plans for the future, summarizing positive gains, and saying goodbye receive the most attention. Despite our best intentions, termination can end up becoming intellectualized. Attachment theory and recent developments in neuroscience offer us a road map for facilitating endings that address client's underlying relational needs, direct us to foster engagement, and help us facilitate new relational experience that can be transformative for clients. We argue that endings in therapy activate client's and therapist's attachments and these endings trigger emotion regulating strategies that can elicit client's engagement or more defensiveness. The current paper will highlight through de-identified case examples how clients automatically respond termination and how therapists can foster rich relational experiences in the here-and-now that clients can take with them. (PsycINFO Database Record (c) 2017 APA, all rights reserved).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920003582','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920003582"><span>Studies of asteroids, comets, and Jupiter's outer satellites</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bowell, Edward</p> <p>1991-01-01</p> <p>Observational, theoretical, and computational research was performed, mainly on asteroids. Two principal areas of research, centering on astrometry and photometry, are interrelated in their aim to study the overall structure of the asteroid belt and the physical and orbital properties of individual asteroids. Two highlights are: detection of CN emission from Chiron; and realization that 1990 MB is the first known Trojan type asteroid of a planet other than Jupiter. A new method of asteroid orbital error analysis, based on Bayesian theory, was developed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930008975','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930008975"><span>Asteroid exploration and utilization: The Hawking explorer</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Carlson, Alan; Date, Medha; Duarte, Manny; Erian, Neil; Gafka, George; Kappler, Peter; Patano, Scott; Perez, Martin; Ponce, Edgar; Radovich, Brian</p> <p>1991-01-01</p> <p>The Earth is nearing depletion of its natural resources at a time when human beings are rapidly expanding the frontiers of space. The resources which may exist on asteroids could have enormous potential for aiding and enhancing human space exploration as well as life on Earth. With the possibly limitless opportunities that exist, it is clear that asteroids are the next step for human existence in space. This report comprises the efforts of NEW WORLDS, Inc. to develop a comprehensive design for an asteroid exploration/sample return mission. This mission is a precursor to proof-of-concept missions that will investigate the validity of mining and materials processing on an asteroid. Project STONER (Systematic Transfer of Near Earth Resources) is based on two utilization scenarios: (1) moving an asteroid to an advantageous location for use by Earth; and (2) mining an asteroids and transporting raw materials back to Earth. The asteroid explorer/sample return mission is designed in the context of both scenarios and is the first phase of a long range plane for humans to utilize asteroid resources. The report concentrates specifically on the selection of the most promising asteroids for exploration and the development of an exploration scenario. Future utilization as well as subsystem requirements of an asteroid sample return probe are also addressed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1991STIN...9318164C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1991STIN...9318164C"><span>Asteroid exploration and utilization: The Hawking explorer</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carlson, Alan; Date, Medha; Duarte, Manny; Erian, Neil; Gafka, George; Kappler, Peter; Patano, Scott; Perez, Martin; Ponce, Edgar; Radovich, Brian</p> <p>1991-12-01</p> <p>The Earth is nearing depletion of its natural resources at a time when human beings are rapidly expanding the frontiers of space. The resources which may exist on asteroids could have enormous potential for aiding and enhancing human space exploration as well as life on Earth. With the possibly limitless opportunities that exist, it is clear that asteroids are the next step for human existence in space. This report comprises the efforts of NEW WORLDS, Inc. to develop a comprehensive design for an asteroid exploration/sample return mission. This mission is a precursor to proof-of-concept missions that will investigate the validity of mining and materials processing on an asteroid. Project STONER (Systematic Transfer of Near Earth Resources) is based on two utilization scenarios: (1) moving an asteroid to an advantageous location for use by Earth; and (2) mining an asteroids and transporting raw materials back to Earth. The asteroid explorer/sample return mission is designed in the context of both scenarios and is the first phase of a long range plane for humans to utilize asteroid resources. The report concentrates specifically on the selection of the most promising asteroids for exploration and the development of an exploration scenario. Future utilization as well as subsystem requirements of an asteroid sample return probe are also addressed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040081211&hterms=Nanotechnology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DNanotechnology','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040081211&hterms=Nanotechnology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DNanotechnology"><span>Autonomous NanoTechnology Swarm (ANTS) Prospecting Asteroid Mission (PAM), Asteroid Proximity Operations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Marr, Greg; Cooley, Steve; Roithmayr, Carlos; Kay-Bunnell, Linda; Williams, Trevor</p> <p>2004-01-01</p> <p>The Autonomous NanoTechnology Swarm (ANTS) is a generic mission architecture based on spatially distributed spacecraft, autonomous and redundant components, and hierarchical organization. The ANTS Prospecting Asteroid Mission (PAM) is an ANTS application which will nominally use a swarm of 1000 spacecraft. There would be 10 types of "specialists" with common spacecraft buses. There would be 10 subswarms of approximately 100 spacecraft each or approximately 10 of each specialist in each swarm. The ANTS PAM primary objective is the exploration of the asteroid belt in search of resources and material with astrobiologically relevant origins and signatures. The ANTS PAM spacecraft will nominally be released from a station in an Earth-Moon L1 libration point orbit, and they will use Solar sails for propulsion. The sail structure would be highly flexible, capable of changing morphology to change cross-section for capture of sunlight or to form effective "tip vanes" for attitude control. ANTS PAM sails would be capable of full to partial deployment, to change effective sail area and center of pressure, and thus allow attitude control. Results of analysis of a transfer trajectory from Earth to a sample target asteroid will be presented. ANTS PAM will require continuous coverage of different asteroid locations as close as one to two asteroid "diameters" from the surface of the asteroid for periods of science data collection during asteroid proximity operations. Hovering spacecraft could meet the science data collection objectives. The results of hovering analysis will be presented. There are locations for which hovering is not possible, for example on the illuminated side of the asteroid. For cases where hovering is not possible, the results of utilizing asteroid formations to orbit the asteroid and achieve the desired asteroid viewing will be presented for sample asteroids. The ability of ANTS PAM to reduce the area of the solar sail during asteroid proximity operations is critical to the maintenance of orbiting formations for a period of time. Results of analysis of potential "traffic" problems during asteroid proximity operations will be presented.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040062092&hterms=MIDAS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DMIDAS','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040062092&hterms=MIDAS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DMIDAS"><span>Lunar and Planetary Science XXXV: Asteroids, Meteors, Comets</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2004-01-01</p> <p>Reports included:Long Term Stability of Mars Trojans; Horseshoe Asteroids and Quasi-satellites in Earth-like Orbits; Effect of Roughness on Visible Reflectance Spectra of Planetary Surface; SUBARU Spectroscopy of Asteroid (832) Karin; Determining Time Scale of Space Weathering; Change of Asteroid Reflectance Spectra by Space Weathering: Pulse Laser Irradiation on Meteorite Samples; Reflectance Spectra of CM2 Chondrite Mighei Irradiated with Pulsed Laser and Implications for Low-Albedo Asteroids and Martian Moons; Meteorite Porosities and Densities: A Review of Trends in the Data; Small Craters in the Inner Solar System: Primaries or Secondaries or Both?; Generation of an Ordinary-Chondrite Regolith by Repetitive Impact; Asteroid Modal Mineralogy Using Hapke Mixing Models: Validation with HED Meteorites; Particle Size Effect in X-Ray Fluorescence at a Large Phase Angle: Importance on Elemental Analysis of Asteroid Eros (433); An Investigation into Solar Wind Depletion of Sulfur in Troilite; Photometric Behaviour Dependent on Solar Phase Angle and Physical Characteristics of Binary Near-Earth-Asteroid (65803) 1996 GT; Spectroscopic Observations of Asteroid 4 Vesta from 1.9 to 3.5 micron: Evidence of Hydrated and/or Hydroxylated Minerals; Multi-Wavelength Observations of Asteroid 2100 Ra-Shalom: Visible, Infrared, and Thermal Spectroscopy Results; New Peculiarities of Cometary Outburst Activity; Preliminary Shape Modeling for the Asteroid (25143) Itokawa, AMICA of Hayabusa Mission; Scientific Capability of MINERVA Rover in Hayabusa Asteroid Mission; Characteristics and Current Status of Near Infrared Spectrometer for Hayabusa Mission; Sampling Strategy and Curation Plan of Hayabusa Asteroid Sample Return Mission; Visible/Near-Infrared Spectral Properties of MUSES C Target Asteroid 25143 Itokawa; Calibration of the NEAR XRS Solar Monitor; Modeling Mosaic Degradation of X-Ray Measurements of 433 Eros by NEAR-Shoemaker; Scattered Light Remediation and Recalibration of near Sheomaker s NIS Global Dataaset at 433 Eros; Evaluation of Preparation and Measuring Techniques for Interplanetary Dust Particles for the MIDAS Experiment on Rosetta; Chiron: a Proposed Remote Sensing Prompt Gamma Ray Activation Analysis Instrument for a Nuclear Powered Prometheus Mission;From Present Surveying to Future Prospecting of the Asteroid Belt; Asteroid Physical Properties Probe Microgravity Testing of a Surface Sampling System for Sample Return from Small Solar System Bodies;and Penetrator Coring Apparatus for Cometary Surfaces.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12804372','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12804372"><span>Impacts and evolution: future prospects.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Morrison, David</p> <p>2003-01-01</p> <p>The discipline of astrobiology includes the dynamics of biological evolution. One of the major ways that the cosmos influences life is through the catastrophic environmental disruptions caused when comets and asteroids collide with a planet. We now recognize that such impacts have caused mass extinctions and played a major role in determining the evolution of life on Earth. The time-averaged impact flux as a function of projectile energy can be derived from lunar cratering statistics as well as the current population of near Earth asteroids (NEAs). Effects of impacts of various energies can be modeled, using data from historic impacts [such as the Cretaceous-Tertiary (KT) impactor 65 million years ago] and the observed 1994 bombardment of Jupiter by fragments of Comet Shoemaker-Levy 9. It is of particular interest to find from such models that the terrestrial environment is highly vulnerable to perturbation from impacts, so that even such a small event as the KT impact (by a projectile 10-15 km in diameter) can lead to a mass extinction. Similar considerations allow us to model the effects of still smaller (and much more likely) impacts, down to the size of the asteroid that exploded over Tunguska in 1908 (energy approximately 10 megatons). Combining the impact flux with estimates of environmental and ecological effects reveals that the greatest contemporary hazard is associated with impactors near 1 million megatons in energy (approximately 2 km in diameter for an asteroid). The current impact hazard is significant relative to other natural hazards, and arguments can be developed to illuminate a variety of public policy issues. The first priority in any plan for defense against impactors is to survey the population of Earth-crossing NEAs and project their orbits forward in time. This is the purpose of the Spaceguard Survey, which has already found more than half of the NEAs >1 km in diameter. If there is an NEA on a collision course with Earth, it can be discovered and the impact predicted with decades or more of warning. It is then possible to consider how to deflect or disrupt the NEA. Unlike other natural hazards, the impact risk can be largely eliminated, given sufficient advanced knowledge to take action against the threatening projectile.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040087637&hterms=extinction+statistics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dextinction%2Bstatistics','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040087637&hterms=extinction+statistics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dextinction%2Bstatistics"><span>Impacts and evolution: future prospects</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Morrison, David</p> <p>2003-01-01</p> <p>The discipline of astrobiology includes the dynamics of biological evolution. One of the major ways that the cosmos influences life is through the catastrophic environmental disruptions caused when comets and asteroids collide with a planet. We now recognize that such impacts have caused mass extinctions and played a major role in determining the evolution of life on Earth. The time-averaged impact flux as a function of projectile energy can be derived from lunar cratering statistics as well as the current population of near Earth asteroids (NEAs). Effects of impacts of various energies can be modeled, using data from historic impacts [such as the Cretaceous-Tertiary (KT) impactor 65 million years ago] and the observed 1994 bombardment of Jupiter by fragments of Comet Shoemaker-Levy 9. It is of particular interest to find from such models that the terrestrial environment is highly vulnerable to perturbation from impacts, so that even such a small event as the KT impact (by a projectile 10-15 km in diameter) can lead to a mass extinction. Similar considerations allow us to model the effects of still smaller (and much more likely) impacts, down to the size of the asteroid that exploded over Tunguska in 1908 (energy approximately 10 megatons). Combining the impact flux with estimates of environmental and ecological effects reveals that the greatest contemporary hazard is associated with impactors near 1 million megatons in energy (approximately 2 km in diameter for an asteroid). The current impact hazard is significant relative to other natural hazards, and arguments can be developed to illuminate a variety of public policy issues. The first priority in any plan for defense against impactors is to survey the population of Earth-crossing NEAs and project their orbits forward in time. This is the purpose of the Spaceguard Survey, which has already found more than half of the NEAs >1 km in diameter. If there is an NEA on a collision course with Earth, it can be discovered and the impact predicted with decades or more of warning. It is then possible to consider how to deflect or disrupt the NEA. Unlike other natural hazards, the impact risk can be largely eliminated, given sufficient advanced knowledge to take action against the threatening projectile.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19780057651&hterms=CHARACTERIZATION+POPULATION&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DCHARACTERIZATION%2BOF%2BTHE%2BPOPULATION','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19780057651&hterms=CHARACTERIZATION+POPULATION&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DCHARACTERIZATION%2BOF%2BTHE%2BPOPULATION"><span>Asteroid surface materials - Mineralogical characterizations and cosmological implications</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gaffey, M. J.; Mccord, T. B.</p> <p>1977-01-01</p> <p>The theoretical basis for the interpretation of diagnostic spectral features is examined and previous characterizations of asteroid surface materials are considered. A summary is provided of results reported by Gaffey and McCord (1977) who have utilized the most sophisticated interpretive techniques available to interpret the spectral reflectance data of about 65 asteroids for mineralogic and petrologic information. Cosmological implications related to the study of asteroid surface materials are also considered, taking into account source bodies for the meteorites, postaccretionary thermal history, significant factors of asteroid thermal history, and the Apollo and Amor asteroids. It is found that the asteroids exhibit surface materials made up of assemblages of meteoritic minerals. The relative abundance of meteorite types reaching the earth's surface is very different from the population of mineralogic types on asteroid surfaces. The earth-crossing or -approaching asteroids apparently derive from a restricted source region or population which is very strongly depleted in the C2-like assemblages that dominate the belt as a whole.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18704080','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18704080"><span>Compositional differences between meteorites and near-Earth asteroids.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vernazza, P; Binzel, R P; Thomas, C A; DeMeo, F E; Bus, S J; Rivkin, A S; Tokunaga, A T</p> <p>2008-08-14</p> <p>Understanding the nature and origin of the asteroid population in Earth's vicinity (near-Earth asteroids, and its subset of potentially hazardous asteroids) is a matter of both scientific interest and practical importance. It is generally expected that the compositions of the asteroids that are most likely to hit Earth should reflect those of the most common meteorites. Here we report that most near-Earth asteroids (including the potentially hazardous subset) have spectral properties quantitatively similar to the class of meteorites known as LL chondrites. The prominent Flora family in the inner part of the asteroid belt shares the same spectral properties, suggesting that it is a dominant source of near-Earth asteroids. The observed similarity of near-Earth asteroids to LL chondrites is, however, surprising, as this meteorite class is relatively rare ( approximately 8 per cent of all meteorite falls). One possible explanation is the role of a size-dependent process, such as the Yarkovsky effect, in transporting material from the main belt.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19940007652&hterms=asteroid+belt&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dasteroid%2Bbelt','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19940007652&hterms=asteroid+belt&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dasteroid%2Bbelt"><span>How diverse is the asteroid belt?</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Burbine, Thomas H.; Bell, Jeffrey F.</p> <p>1993-01-01</p> <p>For approximately twenty years, many different asteroid taxonomies, which used many different observational data sets, have been developed to try to group asteroids into classes that contain members with similar spectral characteristics. However, to understand the structure of the asteroid belt, the resulting classes are only useful if they are grouping together asteroids with somewhat similar mineralogies and thermal histories. Until recently, these taxonomies have focused on spectral reflectance data from 0.3 to 1.1 microns and visual albedo. But in the last five years, observational data sets (e.g., 0.8 to 2.5 microns spectra, CCD spectra, 3 microns spectra, and radar albedos) for a small number of asteroids were compiled that can give a better mineralogical interpretation, but whose use in asteroid taxonomy was relatively limited. Analyses of these 'supplementary' data sets show that most asteroid classes contain members with different compositions and/or thermal histories. To understand the diversity of the asteroid belt, the number of objects with these observations must be expanded and used in the next generation of taxonomies.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930017509','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930017509"><span>The Steward Observatory asteroid relational database</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sykes, Mark V.; Alvarezdelcastillo, Elizabeth M.</p> <p>1992-01-01</p> <p>The Steward Observatory Asteroid Relational Database (SOARD) was created as a flexible tool for undertaking studies of asteroid populations and sub-populations, to probe the biases intrinsic to asteroid databases, to ascertain the completeness of data pertaining to specific problems, to aid in the development of observational programs, and to develop pedagogical materials. To date SOARD has compiled an extensive list of data available on asteroids and made it accessible through a single menu-driven database program. Users may obtain tailored lists of asteroid properties for any subset of asteroids or output files which are suitable for plotting spectral data on individual asteroids. A browse capability allows the user to explore the contents of any data file. SOARD offers, also, an asteroid bibliography containing about 13,000 references. The program has online help as well as user and programmer documentation manuals. SOARD continues to provide data to fulfill requests by members of the astronomical community and will continue to grow as data is added to the database and new features are added to the program.</p> </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"><span>17</span></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><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <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"><span>18</span></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> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020038729','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020038729"><span>Origin of Martian Moons from Binary Asteroid Dissociation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Landis, Geoffrey A.; Lyons, Valerie J. (Technical Monitor)</p> <p>2001-01-01</p> <p>The origin of the Martian moons Deimos and Phobos is controversial. A common hypothesis for their origin is that they are captured asteroids, but the moons show no signs of having been heated by passage through a (hypothetical) thick martian atmosphere, and the mechanism by which an asteroid in solar orbit could shed sufficient orbital energy to be captured into Mars orbit has not been previously elucidated. Since the discovery by the space probe Galileo that the asteroid Ida has a moon 'Dactyl', a significant number of asteroids have been discovered to have smaller asteroids in orbit about them. The existence of asteroid moons provides a mechanism for the capture of the Martian moons (and the small moons of the outer planets). When a binary asteroid makes a close approach to a planet, tidal forces can strip the moon from the asteroid. Depending on the phasing, either or both can then be captured. Clearly, the same process can be used to explain the origin of any of the small moons in the solar system.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20428165','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20428165"><span>Detection of ice and organics on an asteroidal surface.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rivkin, Andrew S; Emery, Joshua P</p> <p>2010-04-29</p> <p>Recent observations, including the discovery in typical asteroidal orbits of objects with cometary characteristics (main-belt comets, or MBCs), have blurred the line between comets and asteroids, although so far neither ice nor organic material has been detected on the surface of an asteroid or directly proven to be an asteroidal constituent. Here we report the spectroscopic detection of water ice and organic material on the asteroid 24 Themis, a detection that has been independently confirmed. 24 Themis belongs to the same dynamical family as three of the five known MBCs, and the presence of ice on 24 Themis is strong evidence that it also is present in the MBCs. We conclude that water ice is more common on asteroids than was previously thought and may be widespread in asteroidal interiors at much smaller heliocentric distances than was previously expected.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920001663','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920001663"><span>Meteorite spectroscopy and characterization of asteroid surface materials</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gaffey, Michael J.</p> <p>1991-01-01</p> <p>The analysis of visible and near-infrared reflectance spectra is the primary means to determine surface mineralogy and petrology of individual asteroids. These individual studies provide the data to investigate the broader relationships between the asteroids and meteorites and between asteroids at different heliocentric distances. The main purpose is to improve the understanding of the origin, evolution, and inter-relationships of the asteroids; of their relationships to the meteorites; and of the processes active and the conditions present in the early inner solar system. Empirical information from the study of asteroids and the meteorites is essential to the adequate development and testing of the theoretical models for the accretion of the terrestrial planets, and for their early post-accretionary evolution. The recent results are outined in the following sections: (1) asteroid igneous processes, and (2) spinel-bearing asteroids and the nebular compositional gradient.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013POBeo..92...55P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013POBeo..92...55P"><span>Asteroid Properties from Photometric Observations: Constraining Non-Gravitational Processes in Asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pravec, P.</p> <p>2013-05-01</p> <p>From October 2012 we run our NEOSource project on the Danish 1.54-m telescope on La Silla. The primary aim of the project is to study non-gravitational processes in asteroids near the Earth and in their source regions in the main asteroidal belt. In my talk, I will give a brief overview of our current knowledge of the asteroidal non- gravitational processes and how we study them with photometric observations. I will talk especially about binary and paired asteroids that appear to be formed by rotational fission, about detecting the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) and BYORP (binary YORP) effects of anisotropic thermal emission from asteroids that change their spins and satellite orbits, and about non-principal axis rotators (the so called "tumblers") among the smallest, super-critically rotating asteroids with sizes < 100 meters.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/22663324-simultaneous-mass-determination-gravitationally-coupled-asteroids','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22663324-simultaneous-mass-determination-gravitationally-coupled-asteroids"><span>Simultaneous Mass Determination for Gravitationally Coupled Asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Baer, James; Chesley, Steven R., E-mail: jimbaer1@earthlink.net</p> <p></p> <p>The conventional least-squares asteroid mass determination algorithm allows us to solve for the mass of a large subject asteroid that is perturbing the trajectory of a smaller test asteroid. However, this algorithm is necessarily a first approximation, ignoring the possibility that the subject asteroid may itself be perturbed by the test asteroid, or that the encounter’s precise geometry may be entangled with encounters involving other asteroids. After reviewing the conventional algorithm, we use it to calculate the masses of 30 main-belt asteroids. Compared to our previous results, we find new mass estimates for eight asteroids (11 Parthenope, 27 Euterpe, 51more » Neimausa, 76 Freia, 121 Hermione, 324 Bamberga, 476 Hedwig, and 532 Herculina) and significantly more precise estimates for six others (2 Pallas, 3 Juno, 4 Vesta, 9 Metis, 16 Psyche, and 88 Thisbe). However, we also find that the conventional algorithm yields questionable results in several gravitationally coupled cases. To address such cases, we describe a new algorithm that allows the epoch state vectors of the subject asteroids to be included as solve-for parameters, allowing for the simultaneous solution of the masses and epoch state vectors of multiple subject and test asteroids. We then apply this algorithm to the same 30 main-belt asteroids and conclude that mass determinations resulting from current and future high-precision astrometric sources (such as Gaia ) should conduct a thorough search for possible gravitational couplings and account for their effects.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E.517C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E.517C"><span>AIDA: Asteroid Impact & Deflection Assessment</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cheng, Andrew; Michel, Patrick; Ulamec, Stephan; Reed, Cheryl; Galvez, Andres; Carnelli, Ian</p> <p></p> <p>On Feb. 15, 2013, an exceptionally close approach to Earth by the small asteroid 2012 DA14 was eagerly awaited by observers, but another small asteroid impacted Earth over Chelyabinsk, Russia the same day without warning, releasing several hundred kilotons TNT of energy and injuring over 1500 people. These dramatic events remind us of the needs to discover hazardous asteroids and to learn how to mitigate them. The AIDA mission is the first demonstration of a mitigation technique to protect the Earth from a potential asteroid impact, by performing a spacecraft kinetic impact on an asteroid to deflect it from its trajectory. We will provide an update on the status of parallel AIDA mission studies supported by ESA and NASA. AIDA is an international collaboration consisting of two independent but mutually supporting missions, one of which is the asteroid kinetic impactor, and the other is the characterization spacecraft which will orbit the asteroid system to monitor the deflection experiment and measure the results. These two missions are the NASA Double Asteroid Redirection Test (DART), which is the kinetic impactor, and the European Space Agency's Asteroid Impact Monitoring (AIM) mission, which is the characterization spacecraft. The target of the AIDA mission will be a binary asteroid, in which DART will target the secondary, smaller member in order to deflect the binary orbit. The resulting period change can be measured to within 10% by ground-based observations. The asteroid deflection will be measured to higher accuracy, and additional results of the DART impact, like the impact crater, will be studied in great detail by the AIM mission. AIDA will return vital data to determine the momentum transfer efficiency of the kinetic impact and key physical properties of the target asteroid. The two mission components of AIDA, DART and AIM, are each independently valuable, but when combined they provide a greatly increased knowledge return. The AIDA mission will combine US and European space experience and expertise to address an international problem, the asteroid impact hazard. AIDA will also be a valuable precursor to human spaceflight to an asteroid, as it would return unique information on an asteroid's strength and internal structure and would be particularly relevant to a human mission for asteroid mitigation. AIDA will furthermore return fundamental new science data on impact cratering, surface properties and interior structure. AIDA will target the binary Near-Earth asteroid Didymos with two independently launched spacecraft, with the deflection experiment to occur in October, 2022.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850058258&hterms=Flora&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DFlora','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850058258&hterms=Flora&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DFlora"><span>Near-earth asteroids - Possible sources from reflectance spectroscopy</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mcfadden, L. A.; Gaffey, M. J.; Mccord, T. B.</p> <p>1985-01-01</p> <p>The diversity of reflectance spectra noted among near-earth asteroids that were compared with selected asteroids, planets and satellites to determine possible source regions is indicative of different mineralogical composition and, accordingly, of more than one source region. Spectral signatures that are similar to those of main belt asteroids support models deriving some of these asteroids from the 5:2 Kirkwood gap and the Flora family, by way of gravitational perturbations. The differences in composition found between near-earth asteroids and planetary and satellite surfaces are in keeping with theoretical arguments that such bodies should not be sources. While some near-earth asteroids furnish portions of the earth's meteorite flux, other sources must also contribute.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16763141','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16763141"><span>The breakup of a main-belt asteroid 450 thousand years ago.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nesvorný, David; Vokrouhlický, David; Bottke, William F</p> <p>2006-06-09</p> <p>Collisions in the asteroid belt frequently lead to catastrophic breakups, where more than half of the target's mass is ejected into space. Several dozen large asteroids have been disrupted by impacts over the past several billion years. These impact events have produced groups of fragments with similar orbits called asteroid families. Here we report the discovery of a very young asteroid family around the object 1270 Datura. Our work takes advantage of a method for identification of recent breakups in the asteroid belt using catalogs of osculating (i.e., instantaneous) asteroid orbits. The very young families show up in these catalogs as clusters in a five-dimensional space of osculating orbital elements.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/AD1014103','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/AD1014103"><span>The Foundations of Operational Resilience Assessing the Ability to Operate in an Anti-Access/Area Denial (A2/AD) Environment: The Analytical Framework, Lexicon, and Characteristics of the Operational Resilience Analysis Model (ORAM)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2016-07-07</p> <p>engineering (CCE) methods, such as aggregate crater fill and laying replacement concrete. [RAND] • Level 2: CCE plus the use of folded fiberglass ( FFM ...or aluminum mats (e.g., AM-2). [RAND] • Level 3: CCE, FFMs , and Critical Runway Assessment and Repair (CRATR) teams. [RAND] Recovery. In air...CSG carrier strike group CTA central terminal area DCA defensive counterair DoD U.S. Department of Defense FFM folded fiber mats FOB forward</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910016778&hterms=child&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dchild','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910016778&hterms=child&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dchild"><span>Accessibility of near-Earth asteroids, 1990</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hulkower, Neal D.; Child, Jack B.</p> <p>1991-01-01</p> <p>Previous research which analyzed the accessibility of all known near-Earth asteroids is updated. Since then, many new near-Earth asteroids have been discovered, and 1928 DB, the most accessible asteroid at that time, has been recovered. Many of these recently discovered near-Earth asteroids have promising orbital characteristics. In addition to accessibility (as defined by minimum global delta v), ideal rendezvous opportunities are identified.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870003019&hterms=Six+Sigma&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DSix%2BSigma','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870003019&hterms=Six+Sigma&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DSix%2BSigma"><span>CCD scanning for asteroids and comets</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gehrels, T.; Mcmillan, R. S.</p> <p>1986-01-01</p> <p>A change coupled device (CCD) is used in a scanning mode to find new asteroids and recover known asteroids and comet nuclei. Current scientific programs include recovery of asteroids and comet nuclei requested by the Minor Planet Center (MPC), discovery of new asteroids in the main belt and of unusual orbital types, and follow-up astrometry of selected new asteroids discovered. The routine six sigma limiting visual magnitude is 19.6 and slightly more than a square degree is scanned three times every 90 minutes of observing time during the fortnight centered on New Moon. Semiautomatic software for detection of moving objects is in routine use; angular speeds as low as 11.0 arcseconds per hour were distinguished from the effects of the Earth's atmosphere on the field of view. A typical set of three 29-minute scans near the opposition point along the ecliptic typically nets at least 5 new main-belt asteroids down to magnitude 19.6. In 18 observing runs (months) 43 asteroids were recovered, astrometric and photometric data on 59 new asteroids were reported, 10 new asteroids with orbital elements were consolidated, and photometry and positions of 22 comets were reported.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1990iam..rept...11.','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1990iam..rept...11."><span>Asteroid search program</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p></p> <p></p> <p>This document is dedicated first to the criteria used to select a candidate asteroid. It contains the known characteristics of this asteroid as well as the assumptions made about it. It ends with a preliminary study of other possible more favorable candidates which might be found in the near future. Special attention is paid to the possible existence of Earth-Sun Trojan asteroids. Second, there is a description of the current state of our limited knowledge about the asteroids, and of the instruments and techniques being used to improve this knowledge. The contribution to asteroid research which can be expected from the new instruments already in space or due to be launched in this decade is then discussed. The last part of this document gives a description of different ways of improving our knowledge about the asteroids, both quantitatively and qualitatively. A proposal requiring reasonable financing and manpower to improve asteroid research is presented. It is believed that the implementation of such a program would have a dramatic effect on asteroid research. For example, a significant increase in both the rate of discovery of asteroids and their corresponding orbital parameters would be obtained. This program could be fully operational 3 years after its implementation.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890007264','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890007264"><span>Studies of asteroids, comets, and Jupiter's outer satellites</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bowell, Edward</p> <p>1988-01-01</p> <p>The work comprises observational, theoretical, and computational research on asteroids, together with a smaller effort concerning the astrometry of comets and Jupiter's satellites JVI through JXIII. Two principal areas of research, centering on astrometry and photometry, are interrelated in their aim to study the overall structure of the asteroid belt and the physical and orbital properties of individual asteroids. About 2000 accurate photographic positions of asteroids and comets, including a number from the Lowell, Palomar, and Goethe-Link archival plate collections, the last of which was donated to us last winter by Indiana University were measured and published. Charge coupled device (CCD) astrometry of 36 faint targets was undertaken, including 4 comets; JVI, JVII, JVIII, JLX, JXI, and JXII; and 26 asteroids, most of which are Earth-approachers. A deep, bias-correctable asteroid survey (LUKAS), the aim of which is to determine the true spatial distribution of asteroids down to subkilometer diameters was started. A series of eight plates at the UK Schmidt telescope that contain images of asteroids as faint as V approximately 22 mag was obtained. Analysis of microdensitometric scans of two plates has shown that about 98 percent of the asteroid images could be identified completely automatically.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=S89-44033&hterms=storyboard&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dstoryboard','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=S89-44033&hterms=storyboard&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dstoryboard"><span>Storyboard GALILEO CRUISE SCIENCE OPPORTUNITIES describes asteroid encounters</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1989-01-01</p> <p>Storyboard with mosaicked image of an asteroid and entitled GALILEO CRUISE SCIENCE OPPORTUNITIES describes asteroid objectives. These objectives include: first asteroid encounter; surface geology, composition size, shape, mass; and relation of primitive bodies to meteorites.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title48-vol7/pdf/CFR-2014-title48-vol7-sec3052-209-71.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title48-vol7/pdf/CFR-2014-title48-vol7-sec3052-209-71.pdf"><span>48 CFR 3052.209-71 - Reserve Officer Training Corps and military recruiting on campus.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-10-01</p> <p>... System DEPARTMENT OF HOMELAND SECURITY, HOMELAND SECURITY ACQUISITION REGULATION (HSAR) CLAUSES AND FORMS... with the Department of Homeland Security; and (2) The Government will terminate this contract for... ineligible for contract award if the Secretary of Defense determines that the institution has a policy or...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title48-vol7/pdf/CFR-2010-title48-vol7-sec3052-209-71.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title48-vol7/pdf/CFR-2010-title48-vol7-sec3052-209-71.pdf"><span>48 CFR 3052.209-71 - Reserve Officer Training Corps and military recruiting on campus.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-10-01</p> <p>... System DEPARTMENT OF HOMELAND SECURITY, HOMELAND SECURITY ACQUISITION REGULATION (HSAR) CLAUSES AND FORMS... with the Department of Homeland Security; and (2) The Government will terminate this contract for... ineligible for contract award if the Secretary of Defense determines that the institution has a policy or...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title33-vol3/pdf/CFR-2011-title33-vol3-sec211-111.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title33-vol3/pdf/CFR-2011-title33-vol3-sec211-111.pdf"><span>33 CFR 211.111 - Certification terminating rights of former owners.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-07-01</p> <p>... of former owners. 211.111 Section 211.111 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE REAL ESTATE ACTIVITIES OF THE CORPS OF ENGINEERS IN CONNECTION... reconveyances, the appropriate District Engineer and the former owner are unable to reach a satisfactory...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title33-vol3/pdf/CFR-2010-title33-vol3-sec211-111.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title33-vol3/pdf/CFR-2010-title33-vol3-sec211-111.pdf"><span>33 CFR 211.111 - Certification terminating rights of former owners.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-07-01</p> <p>... of former owners. 211.111 Section 211.111 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE REAL ESTATE ACTIVITIES OF THE CORPS OF ENGINEERS IN CONNECTION... reconveyances, the appropriate District Engineer and the former owner are unable to reach a satisfactory...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://eric.ed.gov/?q=assisted+AND+suicide&pg=2&id=EJ527235','ERIC'); return false;" href="https://eric.ed.gov/?q=assisted+AND+suicide&pg=2&id=EJ527235"><span>The Ethics of Suicide and Suicide Prevention.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Lester, David; Leenaars, Antoon A.</p> <p>1996-01-01</p> <p>Debates the question of suicide as a defensible choice, particularly for the terminally ill, examining the relevance of such issues as the mortality, rationality, and dynamics of the suicidal act, and the legitimacy of physician-assisted suicide. Contrasting perspectives are articulated by two prominent suicidologists as a spur to the reader's…</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1991Icar...89...14D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1991Icar...89...14D"><span>Earth-approaching asteroid streams</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Drummond, J. D.</p> <p>1991-01-01</p> <p>Three association patterns have been noted among 139 earth-approaching asteroids on the basis of current orbital similarity; these asteroid streams, consisting of two groups of five members and one of four, can be matched to three of the four meteorite-producing fireball streams determined by Halliday et al. (1990). If the asteroid streams are true nonrandom associations, the opportunity arises for studies of an 'exploded' asteroid in the near-earth environment. Near-earth asteroid-search projects are encouraged to search the mean orbit of the present streams in order to discover additional association members.</p> </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"><span>18</span></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><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <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"><span>19</span></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> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/8994031','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/8994031"><span>Depletion of the Outer Asteroid Belt</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liou; Malhotra</p> <p>1997-01-17</p> <p>During the early history of the solar system, it is likely that the outer planets changed their distance from the sun, and hence, their influence on the asteroid belt evolved with time. The gravitational influence of Jupiter and Saturn on the orbital evolution of asteroids in the outer asteroid belt was calculated. The results show that the sweeping of mean motion resonances associated with planetary migration efficiently destabilizes orbits in the outer asteroid belt on a time scale of 10 million years. This mechanism provides an explanation for the observed depletion of asteroids in that region.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19890056410&hterms=inventory&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dinventory','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19890056410&hterms=inventory&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dinventory"><span>Asteroid volatiles inventory</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lebofsky, L. A.; Jones, T. D.; Herbert, F.</p> <p>1989-01-01</p> <p>Asteroids appear in light of telescopic and meteority studies to be the most accessible repositories of early solar system history available. In the cooler regions of the outer asteroid belt, apparently unaffected by severe heating, the C, P, and D populations appear to harbor significant inventories of volatiles; the larger primordial belt population may have had an even greater percentage of volatile-rich, low-albedo asteroids, constituting a potent asteroid for veneering early terrestrial planet atmospheres. The volatile-rich asteroids contain carbon, structurally bound and adsorbed water, as well as remnants of interstellar material predating the solar system.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970022113','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970022113"><span>Depletion of the Outer Asteroid Belt</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Liou, Jer-Chyi; Malhotra, Renu</p> <p>1997-01-01</p> <p>During the early history of the solar system, it is likely that the outer planets changed their distance from the sun, and hence, their influence on the asteroid belt evolved with time. The gravitational influence of Jupiter and Saturn on the orbital evolution of asteroids in the outer asteroid belt was calculated. The results show that the sweeping of mean motion resonances associated with planetary migration efficiently destabilizes orbits in the outer asteroid belt on a time scale of 10 million years. This mechanism provides an explanation for the observed depletion of asteroids in that region.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015LPICo1829.6039J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015LPICo1829.6039J"><span>Recovering and Mining Asteroids with a Gas-Sealed Enclosure</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jenniskens, P.; Damer, B.; Norkus, R.; Pilotz, S.; Grigsby, B.; Adams, C.; Blair, B. R.</p> <p>2015-01-01</p> <p>The internal structure of weakly consolidated rubble piles and primitive asteroids can be studied closer to home, and such asteroids can be mined, if it is possible to create a gas-sealed enclosure around the asteroid.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910015078','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910015078"><span>The Steward Observatory asteroid relational database</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sykes, Mark V.; Alvarezdelcastillo, Elizabeth M.</p> <p>1991-01-01</p> <p>The Steward Observatory Asteroid Relational Database (SOARD) was created as a flexible tool for undertaking studies of asteroid populations and sub-populations, to probe the biases intrinsic to asteroid databases, to ascertain the completeness of data pertaining to specific problems, to aid in the development of observational programs, and to develop pedagogical materials. To date, SOARD has compiled an extensive list of data available on asteroids and made it accessible through a single menu-driven database program. Users may obtain tailored lists of asteroid properties for any subset of asteroids or output files which are suitable for plotting spectral data on individual asteroids. The program has online help as well as user and programmer documentation manuals. The SOARD already has provided data to fulfill requests by members of the astronomical community. The SOARD continues to grow as data is added to the database and new features are added to the program.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28775212','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28775212"><span>Identification of a primordial asteroid family constrains the original planetesimal population.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Delbo', Marco; Walsh, Kevin; Bolin, Bryce; Avdellidou, Chrysa; Morbidelli, Alessandro</p> <p>2017-09-08</p> <p>A quarter of known asteroids is associated with more than 100 distinct asteroid families, meaning that these asteroids originate as impact fragments from the family parent bodies. The determination of which asteroids of the remaining population are members of undiscovered families, or accreted as planetesimals from the protoplanetary disk, would constrain a critical phase of planetary formation by unveiling the unknown planetesimal size distribution. We discovered a 4-billion-year-old asteroid family extending across the entire inner part of the main belt whose members include most of the dark asteroids previously unlinked to families. This allows us to identify some original planetesimals, which are all larger than 35 kilometers, supporting the view of asteroids being born big. Their number matches the known distinct meteorite parent bodies. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018IAUS..330..393A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018IAUS..330..393A"><span>Shape and spin of asteroid 967 Helionape</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Apostolovska, G.; Kostov, A.; Donchev, Z.; Bebekovska, E. Vchkova; Kuzmanovska, O.</p> <p>2018-04-01</p> <p>Knowledge of the spin and shape parameters of the asteroids is very important for understanding of the conditions during the creation of our planetary system and formation of asteroid populations. The main belt asteroid and Flora family member 967 Helionape was observed during five apparitions. The observations were made at the Bulgarian National Astronomical Observatory (BNAO) Rozhen, since March 2006 to March 2016. Lihtcurve inversion method (Kaasalainen et al. (2001)), applied on 12 relative lightcurves obtained at various geometric conditions of the asteroid, reveals the spin vector, the sense of rotation and the preliminary shape model of the asteroid. Our aim is to contribute in increasing the set of asteroids with known spin and shape parameters. This could be done with dense lightcurves, obtained during small number of apparitions, in combination with sparse data produced by photometric asteroid surveys such as the Gaia satellite (Hanush (2011)).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050202045','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050202045"><span>Workshop on Oxygen in Asteroids and Meteorites</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2005-01-01</p> <p>Contents include the following: Constraints on the detection of solar nebula's oxidation state through asteroid observation. Oxidation/Reduction Processes in Primitive Achondrites. Low-Temperature Chemical Processing on Asteroids. On the Formation Location of Asteroids and Meteorites. The Spectral Properties of Angritic Basalts. Correlation Between Chemical and Oxygen Isotopic Compositions in Chondrites. Effect of In-Situ Aqueous Alteration on Thermal Model Heat Budgets. Oxidation-Reduction in Meteorites: The Case of High-Ni Irons. Ureilite Atmospherics: Coming up for Air on a Parent Body. High Temperature Effects Including Oxygen Fugacity, in Pre-Planetary and Planetary Meteorites and Asteroids. Oxygen Isotopic Variation of Asteroidal Materials. High-Temperature Chemical Processing on Asteroids: An Oxygen Isotope Perspective. Oxygen Isotopes and Origin of Opaque Assemblages from the Ningqiang Carbonaceous Chondrite. Water Distribution in the Asteroid Belt. Comparative Planetary Mineralogy: V Systematics in Planetary Pyroxenes and fo 2 Estimates for Basalts from Vesta.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EPSC...11..985G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EPSC...11..985G"><span>ASIME 2016 White Paper: Answers to Questions from the Asteroid Miners</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Galache, Jl; Graps, A. L.; Asime 2016 Contributors, 30</p> <p>2017-09-01</p> <p>The aim of the Asteroid Science Intersections with In-Space Mine Engineering (ASIME) 2016 conference on September 21-22, 2016 in Luxembourg City was to provide an environment for the detailed discussion of the specific properties of asteroids, with the engineering needs of space missions that utilise asteroids. The ASIME 2016 Conference produced a layered record of discussions from the asteroid scientists and the asteroid miners to understand each other's key concerns and to address key scientific questions from the asteroid mining companies: Planetary Resources, Deep Space Industries and TransAstra. These Questions were the focus of the two-day conference, were addressed by scientists inside and outside of the ASIME 2016 Conference and were the focus of this White Paper. The answers in this White Paper point to the Science Knowledge Gaps (SKGs) for advancing the asteroid in-space resource utilisation domain.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170005427','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170005427"><span>Assessment of the Gaussian Covariance Approximation over an Earth-Asteroid Encounter Period</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mattern, Daniel</p> <p>2017-01-01</p> <p>In assessing the risk an asteroid may pose to the Earth, the asteroids state is often predicted for many years, often decades. Only by accounting for the asteroids initial state uncertainty can a measure of the risk be calculated. With the asteroids state uncertainty growing as a function of the initial velocity uncertainty, orbit velocity at the last state update, and the time from the last update to the epoch of interest, the asteroids position uncertainties can grow to many times the size of the Earth when propagated to the encounter risk corridor. This paper examines the merits of propagating the asteroids state covariance as an analytical matrix. The results of this study help to bound the efficacy of applying different metrics for assessing the risk an asteroid poses to the Earth. Additionally, this work identifies a criterion for when different covariance propagation methods are needed to continue predictions after an Earth-encounter period.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110023505','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110023505"><span>Near-Earth Objects: Targets for Future Human Exploration, Solar System Science, Resource Utilization, and Planetary Defense</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Abell, Paul A.</p> <p>2011-01-01</p> <p>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.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201306180003HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201306180003HQ.html"><span>Asteroid Initiative Industry and Partner Day</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2013-06-18</p> <p>NASA Deputy Administrator Lori Garver discusses the progress being made on NASA's mission to capture, redirect, and explore an asteroid during the Asteroid Initiative Industry and Partner Day at NASA Headquarters on Tuesday, June 18, 2013 in Washington. NASA also announced an Asteroid Grand Challenge focused on finding all asteroid threats to human populations and knowing what to do about them. Photo Credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001Icar..149..190L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001Icar..149..190L"><span>A Study of Cybele Asteroids. I. Spin Properties of Ten Asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lagerkvist, Claes-Ingvar; Erikson, Anders; Lahulla, Felix; De Martino, Mario; Nathues, Andreas; Dahlgren, Mats</p> <p>2001-01-01</p> <p>As a part of an observational program on Cybele asteroids we have obtained lightcurves of 10 of the larger asteroids. In this paper the results are presented for 229 Adelinda, 260 Huberta, 401 Ottilia, 420 Bertholda, 466 Tisiphone, 522 Helga, 570 Kythera, 713 Luscinia, 909 Ulla, and 1467 Mashona. Spin properties have been determined for the first time for 8 of these asteroids.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DPS....4730709T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DPS....4730709T"><span>Surprise! The oft-ignored Moon might actually be important for changing the spins of asteroids during Earth flybys</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tuttle Keane, James; Siu, Hosea C.; Moskovitz, Nicholas A.; Binzel, Richard P.</p> <p>2015-11-01</p> <p>Analysis near-Earth asteroid archival data has revealed that asteroids with Earth MOIDs (minimum orbit intersection distance; a proxy for flyby distance) smaller than 1.0-1.5 lunar distances have a systematically larger dispersion in spin rate than more distant flybys (Siu, et al. 2015, DPS). While tidal torques during close encounters are expected to alter the spin states of asteroids (e.g. Scheeres et al. 2000, Icarus), there is no intrinsic reason to expect the observed sharp transition in spin rate distribution at 1.0-1.5 lunar distances, as tidal forces drop off smoothly with distance.While the Moon itself is too diminutive to directly alter the spin-states of asteroids, we show that its presence is enough to significantly affect asteroid encounter trajectories. Asteroids entering the Earth-Moon system are subject to three-body dynamics (due to the combined gravitational effects of the Earth and Moon). Depending on the flyby geometry, the Moon can act as a temporary sink for the asteroid's geocentric orbital energy. This allows some fraction of asteroids to have closer approaches with the Earth than expected when considering the Earth-Moon barycenter alone. In rare cases (~0.1%) this process enables the capture of temporary moons around the Earth (Granvik et al. 2012, Icarus). Asteroids that undergo these "enhanced" flybys can have both closer-than-expected encounter distances (resulting in more significant tidal perturbations), and repeated encounters with the Earth and Moon before leaving the system (resulting in the accumulation of multiple tidal interactions). By numerically solving the circular restricted three-body problem, we show that this process naturally produces a sharp transition in the asteroid population: asteroids with MOIDs less than 1.5 lunar distances can undergo these enhanced close approaches, possibly explaining the sharp transition in the dispersion of asteroid spin rates at this distance. Future work will investigate the efficiency of this process, and the relationship between the physical response of the asteroid to tidal perturbations and the statistical distribution of asteroid spin rates.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140003563','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140003563"><span>Asteroid Redirect Crewed Mission Nominal Design and Performance</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Condon, Gerald; williams, Jacob</p> <p>2014-01-01</p> <p>In 2010, the President announced that, in 2025, the U.S. intended to launch a human mission to an asteroid [1]. This announcement was followed by the idea of a Capability Driven Framework (CDF) [2], which is based on the idea of evolving capabilities from less demanding to more demanding missions to multiple possible destinations and with increased flexibility, cost effectiveness and sustainability. Focused missions, such as a NASA inter-Center study that examined the viability and implications of sending a crew to a Near Earth Asteroid (NEA) [3], provided a way to better understand and evaluate the utility of these CDF capabilities when applied to an actual mission. The long duration of the NEA missions were contrasted with a concept described in a study prepared for the Keck Institute of Space Studies (KISS) [4] where a robotic spacecraft would redirect an asteroid to the Earth-Moon vicinity, where a relatively short duration crewed mission could be conducted to the captured asteroid. This mission concept was included in the National Aeronautics and Space Administration (NASA) fiscal year 2014 budget request, as submitted by the NASA Administrator [5]. NASA studies continued to examine the idea of a crewed mission to a captured asteroid in the Earth-Moon vicinity. During this time was an announcement of NASA's Asteroid Grand Challenge [6]. Key goals for the Asteroid Grand Challenge are to locate, redirect, and explore an asteroid, as well as find and plan for asteroid threats. An Asteroid Redirect Mission (ARM) study was being conducted, which supports this Grand Challenge by providing understanding in how to execute an asteroid rendezvous, capture it, and redirect it to Earth-Moon space, and, in particular, to a distant retrograde orbit (DRO). Subsequent to the returning of the asteroid to a DRO, would be the launch of a crewed mission to rendezvous with the redirected asteroid. This report examines that crewed mission by assessing the Asteroid Redirect Crewed Mission (ARCM) nominal design and performance costs associated with an Orion based crewed rendezvous mission to a captured asteroid in an Earth-Moon DRO. The ARM study includes two fundamental mission phases: 1) The Asteroid Redirect Robotic Mission (ARRM) and 2) the ARCM. The ARRM includes a solar electric propulsion based robotic asteroid return vehicle (ARV) sent to rendezvous with a selected near Earth asteroid, capture it, and return it to a DRO in the Earth-Moon vicinity. The DRO is selected over other possible asteroid parking orbits due to its achievability (by both the robotic and crewed vehicles) and by its stability (e.g., no orbit maintenance is required). After the return of the asteroid to the Earth-Moon vicinity, the ARCM is executed and carries a crew of two astronauts to a DRO to rendezvous with the awaiting ARV with the asteroid. The outbound and inbound transfers employ lunar gravity assist (LGA) flybys to reduce the Orion propellant requirement for the overall nominal mission, which provides a nominal mission with some reserve propellant for possible abort situations. The nominal mission described in this report provides a better understanding of the mission considerations as well as the feasibility of such a crewed mission, particularly with regard to spacecraft currently undergoing development, such as the Orion vehicle and the Space Launch System (SLS).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AJ....155...96H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AJ....155...96H"><span>Asteroid Family Associations of Active Asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hsieh, Henry H.; Novaković, Bojan; Kim, Yoonyoung; Brasser, Ramon</p> <p>2018-02-01</p> <p>We report on the results of a systematic search for associated asteroid families for all active asteroids known to date. We find that 10 out of 12 main-belt comets (MBCs) and five out of seven disrupted asteroids are linked with known or candidate families, rates that have ∼0.1% and ∼6% probabilities, respectively, of occurring by chance, given the overall family association rate of 37% for asteroids in the main asteroid belt. We find previously unidentified family associations between 238P/Read and the candidate Gorchakov family, 311P/PANSTARRS and the candidate Behrens family, 324P/La Sagra and the Alauda family, 354P/LINEAR and the Baptistina family, P/2013 R3-B (Catalina-PANSTARRS) and the Mandragora family, P/2015 X6 (PANSTARRS) and the Aeolia family, P/2016 G1 (PANSTARRS) and the Adeona family, and P/2016 J1-A/B (PANSTARRS) and the Theobalda family. All MBCs with family associations belong to families that contain asteroids with primitive taxonomic classifications and low average reported albedos (\\overline{{p}V}≲ 0.10), while disrupted asteroids with family associations belong to families that contain asteroids that span wider ranges of taxonomic types and average reported albedos (0.06< \\overline{{p}V}< 0.25). These findings are consistent with MBC activity being closely correlated to composition (i.e., whether an object is likely to contain ice), while disrupted asteroid activity is not as sensitive to composition. Given our results, we describe a sequence of processes by which the formation of young asteroid families could lead to the production of present-day MBCs.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018Icar..304..162G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018Icar..304..162G"><span>Resurfacing asteroids from YORP spin-up and failure</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Graves, Kevin J.; Minton, David A.; Hirabayashi, Masatoshi; DeMeo, Francesca E.; Carry, Benoit</p> <p>2018-04-01</p> <p>The spectral properties of S and Q-type asteroids can change over time due to interaction with the solar wind and micrometeorite impacts in a process known as 'space weathering.' Space weathering raises the spectral slope and decreases the 1 μm absorption band depth in the spectra of S and Q-type asteroids. Over time, Q-type asteroids, which have very similar spectra to ordinary chondrite meteorites, will change into S-type asteroids. Because there are a significant number of Q-type asteroids, there must be some process which is resurfacing S-type asteroids into Q-types. In this study, we use asteroid data from the Sloan Digital Sky Survey to show a trend between the slope through the g‧, r‧, and i‧ filters, called the gri-slope, and size that holds for all populations of S and Q-type asteroids in the inner solar system, regardless of orbit. We model the evolution of a suite of asteroids in a Monte Carlo YORP rotational evolution and space weathering model. We show that spin-up and failure from YORP is one of the key resurfacing mechanisms that creates the observed weathering trends with size. By varying the non-dimensional YORP coefficient and running time of the present model over the range 475-1425 Myr, we find a range of values for the space weathering timescale, τSW ≈ 19-80 Myr at 2.2 AU. We also estimate the time to weather a newly resurfaced Q-type asteroid into an S-complex asteroid at 1 AU, τQ → S(1AU) ≈ 2-7 Myr.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/21255716-asteroid-distribution-ecliptic','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/21255716-asteroid-distribution-ecliptic"><span>THE ASTEROID DISTRIBUTION IN THE ECLIPTIC</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Ryan, Erin Lee; Woodward, Charles E.; Dipaolo, Andrea</p> <p>2009-06-15</p> <p>We present analysis of the asteroid surface density distribution of main-belt asteroids (mean perihelion {delta} {approx_equal} 2.404 AU) in five ecliptic latitude fields, -17 {approx}> {beta}({sup 0}) {approx}< +15, derived from deep Large Binocular Telescope V-band (85% completeness limit V = 21.3 mag) and Spitzer Space Telescope IRAC 8.0 {mu}m (80% completeness limit {approx}103 {mu}Jy) fields enabling us to probe the 0.5-1.0 km diameter asteroid population. We discovered 58 new asteroids in the optical survey as well as 41 new bodies in the Spitzer fields. The derived power-law slopes of the number of asteroids per square degree are similar withinmore » each {approx}5{sup 0} ecliptic latitude bin with a mean value of -0.111 {+-} 0.077. For the 23 known asteroids detected in all four IRAC channels mean albedos range from 0.24 {+-} 0.07 to 0.10 {+-} 0.05. No low-albedo asteroids (p{sub V} {approx}< 0.1) were detected in the Spitzer FLS fields, whereas in the SWIRE fields they are frequent. The SWIRE data clearly samples asteroids in the middle and outer belts providing the first estimates of these km-sized asteroids' albedos. Our observed asteroid number densities at optical wavelengths are generally consistent with those derived from the Standard Asteroid Model within the ecliptic plane. However, we find an overdensity at {beta} {approx}> 5{sup 0} in our optical fields, while the infrared number densities are underdense by factors of 2 to 3 at all ecliptic latitudes.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AJ....156...11H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AJ....156...11H"><span>Basalt or Not? Near-infrared Spectra, Surface Mineralogical Estimates, and Meteorite Analogs for 33 Vp-type Asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hardersen, Paul S.; Reddy, Vishnu; Cloutis, Edward; Nowinski, Matt; Dievendorf, Margaret; Genet, Russell M.; Becker, Savan; Roberts, Rachel</p> <p>2018-07-01</p> <p>Investigations of the main asteroid belt and efforts to constrain that population’s physical characteristics involve the daunting task of studying hundreds of thousands of small bodies. Taxonomic systems are routinely employed to study the large-scale nature of the asteroid belt because they utilize common observational parameters, but asteroid taxonomies only define broadly observable properties and are not compositionally diagnostic. This work builds upon the results of work by Hardersen et al., which has the goal of constraining the abundance and distribution of basaltic asteroids throughout the main asteroid belt. We report on the near-infrared (NIR: 0.7 to 2.5 μm) reflectance spectra, surface mineralogical characterizations, analysis of spectral band parameters, and meteorite analogs for 33 Vp asteroids. NIR reflectance spectroscopy is an effective remote sensing technique to detect most pyroxene group minerals, which are spectrally distinct with two very broad spectral absorptions at ∼0.9 and ∼1.9 μm. Combined with the results from Hardersen et al., we identify basaltic asteroids for ∼95% (39/41) of our inner-belt Vp sample, but only ∼25% (2/8) of the outer-belt Vp sample. Inner-belt basaltic asteroids are most likely associated with (4) Vesta and represent impact fragments ejected from previous collisions. Outer-belt Vp asteroids exhibit disparate spectral, mineralogical, and meteorite analog characteristics and likely originate from diverse parent bodies. The discovery of two additional likely basaltic asteroids provides additional evidence for an outer-belt basaltic asteroid population.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17797965','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17797965"><span>Mining the apollo and amor asteroids.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>O'leary, B</p> <p>1977-07-22</p> <p>Earth-approaching asteroids could provide raw materials for space manufacturing. For certain asteroids the total energy per unit mass for the transfer of asteroidal resources to a manufacturing site in high Earth orbit is comparable to that for lunar materials. For logistical reasons the cost may be many times less. Optical studies suggest that these asteroids have compositions corresponding to those of carbonaceous and ordinary chondrites, with some containing large quantities of iron and nickel; others are thought to contain carbon, nitrogen, and hydrogen, elements that appear to be lacking on the moon. The prospect that several new candidate asteroids will be discovered over the next few years increases the likelihood that a variety of asteroidal resource materials can be retrieved on low-energy missions.</p> </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"><span>19</span></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><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <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"><span>20</span></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> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19780003049','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19780003049"><span>Asteroid surface materials: Mineralogical characterizations from reflectance spectra</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gaffey, M. J.; Mccord, T. B.</p> <p>1977-01-01</p> <p>Mineral assemblages analogous to most meteorite types, with the exception of ordinary chondritic assemblages, have been found as surface materials of Main Belt asteroids. C1- and C2-like assemblages (unleached, oxidized meteoritic clay minerals plus opaques such as carbon) dominate the population throughout the Belt, especially in the outer Belt. A smaller population of asteroids exhibit surface materials similar to C3 (CO, CV) meteoritic assemblages (olivine plus opaque, probably carbon) and are also distributed throughout the Belt. The majority of remaining studied asteroids (20) of 65 asteroids exhibit spectral reflectance curves dominated by the presence of metallic nickel-iron in their surface materials. The C2-like materials which dominate the main asteroid belt population appear to be relatively rare on earth-approaching asteroids.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900039980&hterms=histoire&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dhistoire','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900039980&hterms=histoire&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dhistoire"><span>Meteoritic parent bodies - Nature, number, size and relation to present-day asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lipschutz, Michael E.; Gaffey, Michael J.; Pellas, Paul</p> <p>1989-01-01</p> <p>The relationship between meteoritic parent bodies and the present-day asteroids is discussed. Results on oxygen isotopic signatures and chemical distinctions among meteorite classes indicate that meteorites derive from a small number of parent bodies relative to the number of asteroids. The spectral properties of the ordinary chondrites and similar inclusions in meteoritic breccias differ from those of the abundant S asteroids (with no process known that can account for these differences); the closest spectral analogs of these chondrites are the rare near-earth Q-type asteroids. These facts lead to the question of why abundant meteorites have rare asteroidal analogs, while the abundant asteroids have rare meteoritic analogs. This question constitutes a prime topic for future studies.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19770057796&hterms=asteroid+mining&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dasteroid%2Bmining','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19770057796&hterms=asteroid+mining&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dasteroid%2Bmining"><span>Mining the Apollo and Amor asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Oleary, B.</p> <p>1977-01-01</p> <p>Earth-approaching asteroids could provide raw materials for space manufacturing. For certain asteroids the total energy per unit mass for the transfer of asteroidal resources to a manufacturing site in high earth orbit is comparable to that for lunar materials. For logistical reasons the cost may be many times less. Optical studies suggest that these asteroids have compositions corresponding to those of carbonaceous and ordinary chondrites, with some containing large quantities of iron and nickel; other are thought to contain carbon, nitrogen, and hydrogen, elements that appear to be lacking on the moon. The prospect that several new candidate asteroids will be discovered over the next few years increases the likelihood that a variety of asteroidal resource materials can be retrieved on low-energy missions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007LPI....38.1093K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007LPI....38.1093K"><span>Electromagnetic Spacecraft Used for Magnetic Navigation Within Asteroid Belt, Mining Concepts and Asteroid Magnetic Classification</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kletetschka, G.; Adachi, T.; Mikula, V.</p> <p>2007-03-01</p> <p>Application of expandable/collapsible magnetic coil increases/decreases spacecraft velocity without using chemical propellants, allows effective mining of metals from asteroids and is used for the first order classification of asteroids.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017A%26A...600A.126L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017A%26A...600A.126L"><span>V-type candidates and Vesta family asteroids in the Moving Objects VISTA (MOVIS) catalogue</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Licandro, J.; Popescu, M.; Morate, D.; de León, J.</p> <p>2017-04-01</p> <p>Context. Basaltic asteroids (spectrally classified as V-types) are believed to be fragments of large differentiated bodies. The majority of them are found in the inner part of the asteroid belt, and are current or past members of the Vesta family. Recently, some V-type asteroids have been discovered far from the Vesta family supporting the hypothesis of the presence of multiple basaltic asteroids in the early solar system. The discovery of basaltic asteroids in the outer belt challenged the models of the radial extent and the variability of the temperature distribution in the early solar system. Aims: We aim to identify new basaltic V-type asteroids using near-infrared colors of 40 000 asteroids observed by the VHS-VISTA survey and compiled in the MOVIS-C catalogue. We also want to study their near-infrared colors and to study the near-infrared color distribution of the Vesta dynamical family. Methods: We performed a search in the MOVIS-C catalogue of all the asteroids with (Y-J) and (J-Ks) in the range (Y-J) ≥ 0.5 and (J-Ks) ≤ 0.3, associated with V-type asteroids, and studied their color distribution. We have also analyzed the near-infrared color distribution of 273 asteroid members of the Vesta family and compared them with the albedo and visible colors from WISE and SDSS data. We determined the fraction of V-type asteroids in the family. Results: We found 477 V-type candidates in MOVIS-C, 244 of them outside the Vesta dynamical family. We identified 19 V-type asteroids beyond the 3:1 mean motion resonance, 6 of them in the outer main belt, and 16 V-types in the inner main belt with proper inclination Ip ≤ 3.0°, well below the inclination of the Vesta family. We computed that 85% of the members of the Vesta dynamical family are V-type asteroids, and only 1-2% are primitive class asteroids and unlikely members of the family. Conclusions: This work almost doubles the sample of basaltic asteroid candidates in regions outside the Vesta family. Spectroscopic studies in the near-infrared and dynamical studies are needed to confirm their basaltic composition and to determine their origin.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170010282','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170010282"><span>Overview of the Mission Design Reference Trajectory for NASA's Asteroid Redirect Robotic Mission</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mcguire, Melissa L.; Strange, Nathan J.; Burke, Laura M.; McCarty, Steven L.; Lantoine, Gregory B.; Qu, Min; Shen, Haijun; Smith, David A.; Vavrina, Matthew A.</p> <p>2017-01-01</p> <p>The National Aeronautics and Space Administration's (NASA's) recently cancelled Asteroid Redirect Mission was proposed to rendezvous with and characterize a 100 m plus class near-Earth asteroid and provide the capability to capture and retrieve a boulder off of the surface of the asteroid and bring the asteroidal material back to cislunar space. Leveraging the best of NASA's science, technology, and human exploration efforts, this mission was originally conceived to support observation campaigns, advanced solar electric propulsion, and NASA's Space Launch System heavy-lift rocket and Orion crew vehicle. The asteroid characterization and capture portion of ARM was referred to as the Asteroid Redirect Robotic Mission (ARRM) and was focused on the robotic capture and then redirection of an asteroidal boulder mass from the reference target, asteroid 2008 EV5, into an orbit near the Moon, referred to as a Near Rectilinear Halo Orbit where astronauts would visit and study it. The purpose of this paper is to document the final reference trajectory of ARRM and the challenges and unique methods employed in the trajectory design of the mission.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19870013939','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19870013939"><span>Evolution of the inner asteroid belt: Paradigms and paradoxes from spectral studies</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gaffey, Michael J.</p> <p>1987-01-01</p> <p>Recent years have witnessed a significant increase in the sophistication of asteroidal surface material characterizations derived from spectral data. An extensive data base of moderate to high spectral resolution, visible and near-infrared asteroid spectra is now available. Interpretive methodologies and calibrations were developed to determine phase abundance and composition in olivine-pyroxene assemblages and to estimate NiFe metal abundance from such spectra. A modified version of the asteroid classifications system more closely parallels the mineralogic variations of the major inner belt asteroid types. These improvements permit several general conclusions to be drawn concerning the nature of inner belt objects; their history, and that of the inner solar system; and the relationship between the asteroids and meteorites. Essentially all large belt asteroids have or are fragments of parent bodies which have undergone strong post-accretionary heating, varying degrees of melting and magmatic differentiation, and subsequent collisional disruption. These asteroids show a systematic, but not yet well characterized, mineralogic variation with semi-major axis. This suggests that the S-type asteroid families represent relatively recent collisions onto the cores of previously disrupted parent bodies.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010094058','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010094058"><span>Asteroid Size-Frequency Distribution (The ISO Deep Asteroid Survey)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tedesco, Edward F.</p> <p>2001-01-01</p> <p>A total of six deep exposures (using AOT CAM01 with a 6" PFOV) through the ISOCAM LW10 filter (IRAS Band 1, i.e., 12 micro-m) were obtained on an approximately 15 arcminute square field centered on the ecliptic plane. Point sources were extracted using the technique described by Desert, et al. Two known asteroids appear in these frames and 20 sources moving with velocities appropriate for main belt asteroids are present. Most of the asteroids detected have flux densities less than 1 mJy, i.e., between 150 and 350 times fainter than any of the asteroids observed by Infrared Astronomy Satellite (IRAS). These data provide the first direct measurement of the 12 micro-m sky-plane density for asteroids on the ecliptic equator. The median zodiacal foreground, as measured by ISOCAM during this survey, is found to be 22.1 +/- 1.5 mJy per pixel, i.e., 26.2 +/- 1.7 MJy/sr. The results presented here imply that the actual number of kilometer-sized asteroids is significantly greater than previously believed and in reasonable agreement with the Statistical Asteroid Model.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150016608','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150016608"><span>Asteroid and Lava Tube In Situ Resource Utilization (ISRU) Prospecting Free Flyer Project</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Falker, John; Zeitlin, Nancy; Mueller, Robert; Dupuis, Michael</p> <p>2015-01-01</p> <p>This project seeks to develop a small free flyer that can be used to safely and effectively prospect on an Asteroid while being controlled by the crew. This will enable the characterization of the Asteroid for the In Situ Resource Utilization (ISRU). Lava tubes can be explored remotely from the outside Asteroids can contain vast amounts of resources such as water for propellants and metals for feed stocks. Lava Tubes on Mars and the Moon may contain frozen volatile resources. Before the resources can be used, they must be found with a prospecting method. The NASA Agency Asteroid Grand Challenge seeks new ideas for Asteroid retrieval mission technologies for exploration and utilization of asteroids in a Distant Retrograde Orbit (DRO). This project will develop a small free flying platform that can be used to safely and effectively prospect on an Asteroid with limited autonomy while being controlled by the crew. This will enable the characterization of the Asteroid for ISRU. Lava tubes can be explored remotely from the outside as well using this same technology.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4467028','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4467028"><span>Auditory cortex controls sound-driven innate defense behaviour through corticofugal projections to inferior colliculus</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Xiong, Xiaorui R.; Liang, Feixue; Zingg, Brian; Ji, Xu-ying; Ibrahim, Leena A.; Tao, Huizhong W.; Zhang, Li I.</p> <p>2015-01-01</p> <p>Defense against environmental threats is essential for animal survival. However, the neural circuits responsible for transforming unconditioned sensory stimuli and generating defensive behaviours remain largely unclear. Here, we show that corticofugal neurons in the auditory cortex (ACx) targeting the inferior colliculus (IC) mediate an innate, sound-induced flight behaviour. Optogenetic activation of these neurons, or their projection terminals in the IC, is sufficient for initiating flight responses, while the inhibition of these projections reduces sound-induced flight responses. Corticocollicular axons monosynaptically innervate neurons in the cortex of the IC (ICx), and optogenetic activation of the projections from the ICx to the dorsal periaqueductal gray is sufficient for provoking flight behaviours. Our results suggest that ACx can both amplify innate acoustic-motor responses and directly drive flight behaviours in the absence of sound input through corticocollicular projections to ICx. Such corticofugal control may be a general feature of innate defense circuits across sensory modalities. PMID:26068082</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA14404.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA14404.html"><span>Trojan Asteroid Shares Orbit with Earth Artist Animation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2011-07-27</p> <p>This artist concept illustrates the first known Earth Trojan asteroid, discovered by NEOWISE, the asteroid-hunting portion of NASA WISE mission. The asteroid is shown in gray and its extreme orbit is shown in green. Objects are not drawn to scale.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920001723','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920001723"><span>Asteroid surface processes: Experimental studies of the solar wind on reflectance and optical properties of asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mcfadden, Lucy-Ann</p> <p>1991-01-01</p> <p>The effect of the solar wind on the optical properties of meteorites was studied to determine whether the solar wind can alter the properties of ordinary chondrite parent bodies resulting in the spectral properties of S-type asteroids. The existing database of optical properties of asteroids was analyzed to determine the effect of solar wind in altering asteroid surface properties.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EPSC...11...37M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EPSC...11...37M"><span>Asteroid Impact Mission: relevance to asteroid mining</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Michel, P.; Kueppers, M.; Carnelli, I.</p> <p>2017-09-01</p> <p>The Asteroid Impact Mission (AIM) is the European (ESA) component of the AIDA mission in collaboration with NASA. The objectives of AIDA are: (1) to perform a test of asteroid deflection using a kinetic impactor with the USA (NASA) component DART, and (2) with AIM, to investigate the binary near-Earth asteroid Didymos, in particular its secondary and target of DART, with data of high value for mining purposes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EPSC...11..159R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EPSC...11..159R"><span>A Study of the Effects of Faint Dust Comae on the Spectra of Asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rondón, E.; Carvano, J.; Lorenz-Martins, S.</p> <p>2017-09-01</p> <p>The presence of dust comae on asteroids and centaurs is a phenomenon that became accepted in the last decades and which challenges the traditional definitions of asteroids and comets. A possible way of improving the chances of discovery of Active Asteroids is to use large multi-colour surveys or catalogs, like SDSS Moving Object Catalog. In this work we analyze the effects of faint dust comae on asteroid spectra and then use it to investigate the effects that a faint dust comae would have over the spectrum, magnitude, and radial profile of asteroids.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20110015590&hterms=earth+landing&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dearth%2Blanding','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20110015590&hterms=earth+landing&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dearth%2Blanding"><span>NASA's Human Mission to a Near-Earth Asteroid: Landing on a Moving Target</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Smith, Jeffrey H.; Lincoln, William P.; Weisbin, Charles R.</p> <p>2011-01-01</p> <p>This paper describes a Bayesian approach for comparing the productivity and cost-risk tradeoffs of sending versus not sending one or more robotic surveyor missions prior to a human mission to land on an asteroid. The expected value of sample information based on productivity combined with parametric variations in the prior probability an asteroid might be found suitable for landing were used to assess the optimal number of spacecraft and asteroids to survey. The analysis supports the value of surveyor missions to asteroids and indicates one launch with two spacecraft going simultaneously to two independent asteroids appears optimal.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850060549&hterms=psyche&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dpsyche','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850060549&hterms=psyche&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dpsyche"><span>Mainbelt asteroids - Dual-polarization radar observations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ostro, S. J.; Campbell, D. B.; Shapiro, I. I.</p> <p>1985-01-01</p> <p>Observations of 20 asteroids in the main belt between Mars and Jupiter provide information about the nature of these objects' surfaces at centimeter-to-kilometer scales. At least one asteroid (Pallas) is extremely smooth at centimeter-to-meter scales. Each asteroid appears much rougher than the moon at some scale between several meters and many kilometers. The range of asteroid radar albedos is very broad and implies substantial variations in porosity or metal concentration (or both). The highest albedo estimate, for the asteroid Psyche, is consistent with a surface having porosities typical of lunar soil and a composition nearly entirely metallic.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170001951','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170001951"><span>NASA's Asteroid Redirect Mission (ARM)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Abell, P. A.; Mazanek, D. D.; Reeves, D. M.; Chodas, P. W.; Gates, M. M.; Johnson, L. N.; Ticker, R. L.</p> <p>2017-01-01</p> <p>Mission Description and Objectives: NASA's Asteroid Redirect Mission (ARM) consists of two mission segments: 1) the Asteroid Redirect Robotic Mission (ARRM), a robotic mission to visit a large (greater than approximately 100 meters diameter) near-Earth asteroid (NEA), collect a multi-ton boulder from its surface along with regolith samples, and return the asteroidal material to a stable orbit around the Moon; and 2) the Asteroid Redirect Crewed Mission (ARCM), in which astronauts will explore and investigate the boulder and return to Earth with samples. The ARRM is currently planned to launch at the end of 2021 and the ARCM is scheduled for late 2026.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DDA....4630104M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DDA....4630104M"><span>Stochastic YORP On Real Asteroid Shapes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McMahon, Jay W.</p> <p>2015-05-01</p> <p>Since its theoretical foundation and subsequent observational verification, the YORP effect has been understood to be a fundamental process that controls the evolution of small asteroids in the inner solar system. In particular, the coupling of the YORP and Yarkovsky effects are hypothesized to be largely responsible for the transport of asteroids from the main belt to the inner solar system populations. Furthermore, the YORP effect is thought to lead to rotational fission of small asteroids, which leads to the creation of multiple asteroid systems, contact binary asteroids, and asteroid pairs. However recent studies have called into question the ability of YORP to produce these results. In particular, the high sensitivity of the YORP coefficients to variations in the shape of an asteroid, combined with the possibility of a changing shape due to YORP accelerated spin rates can combine to create a stochastic YORP coefficient which can arrest or change the evolution of a small asteroid's spin state. In this talk, initial results are presented from new simulations which comprehensively model the stochastic YORP process. Shape change is governed by the surface slopes on radar based asteroid shape models, where the highest slope regions change first. The investigation of the modification of YORP coefficients and subsequent spin state evolution as a result of this dynamically influenced shape change is presented and discussed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MNRAS.475..353M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MNRAS.475..353M"><span>Spectroscopy of five V-type asteroids in the middle and outer main belt</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Migliorini, Alessandra; De Sanctis, M. C.; Lazzaro, D.; Ammannito, E.</p> <p>2018-03-01</p> <p>The origin of basaltic asteroids found in the middle and outer main belt is an open question. These asteroids are not dynamically linked to the Vesta collisional family and can be the remnants of other large differentiated asteroids present in the early phases of the main belt but destroyed long ago. Spectroscopic investigation of some V-type asteroids in the middle-outer belt, classified as such by their SLOAN photometric colours (Ivezić et al.) and WISE albedos (Masiero et al.), has revealed that their spectra are more similar to other taxonomic classes, like -Q, R, S, or A (Jasmim et al. and Oszkiewicz et al.). Here, we report about the observation, in the near-infrared spectral range, of five V-type asteroids located beyond 2.5 au. These observations allowed us to infer their taxonomic classification. Two asteroids, (21238) Panarea (observed in a previous campaign but here included for comparison) and (105041) 2000 KO41, confirm their basaltic nature. For asteroids (10800) 1992 OM8 and (15898) Kharasterteam a taxonomic classification is more uncertain, being either Q- or S-type. Asteroid (14390) 1990 QP10 classification is difficult to ascribe to the known taxonomic classes, maybe due to the low-quality spectrum. Further observations are desirable for this asteroid.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010cosp...38..683D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010cosp...38..683D"><span>V-type asteroids investigation in support to the NASA DAWN mission</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>de Sanctis, Maria Cristina; Migliorini, Alessandra; Lazzaro, Daniela; Luzia, Flavia; Ammannito, Eleonora; Capria, Maria Teresa; Filacchione, Gianrico; Mottola, Stefano; Boschin, Walter; Fiorenzano, Aldo; Ghinassi, Francesca</p> <p></p> <p>4Vesta crust composition suggests that it has undergone extensive differentiation and resur-facing. It is the only large basaltic asteroid known at present (McCord, (1970); McFadden et al., (1977); Binzel, et al., (1997)), and it could be the smallest differentiated body of the Solar System. The NASA mission DAWN, launched on September 2007, is intended to deeper investigate the mineralogical properties of 4Vesta, in order to shed light on this puzzle (Russell et al., 2007). Although 4Vesta is the only large object in the Solar System which shows an almost intact basaltic crust, however an increasing number of small asteroids with a similar surface composition as 4Vesta were discovered thanks to ground-based telescopes (Xu et al., (1995); Burbine et al., (2001); Alvarez-Candal, et al. (2006)), posing the fundamental problem of the presence and distribution of basaltic material in the Solar System. Many of these asteroids were found to be spectrally and dynamically linked to 4Vesta, and they are known as the Vesta family. However, the scenario is much more complicated, because many Main Belt Asteroids, classified as V-type asteroids, were discovered near but not dynamically linked to 4Vesta. However, numerical simulations indicate that a relatively large fraction of the original Vesta family members may have evolved out of the family borders (Nesvorny et al., 2008); on the other hand, this seems not to be true for the low inclined asteroids, for which instead a different origin must be assumed. At present, more than 500 asteroids are classified as potentially V-type asteroids, thanks to new photometric investigation (Roig and Gil-Hutton, (2006); Roig et al., (2008); Moskoviz et al., (2008)). Some of these objects possibly belong to the Vesta-family, according to dynamical considerations, while other asteroids seem to be not clearly related to Vesta. Ground-based observations allow to investigate the spectral properties and hence the miner-alogical composition of such asteroids, which are thought to be linked to 4Vesta, because of their colors, but they are still unclassified. Asteroids were selected among the Vesta and non-Vesta family. The selected asteroids are potentially fragments coming from 4Vesta, after a cratering event on the asteroid. The possible co-existence of distinct mineralogical groups among the V-type asteroids is suggested by previous asteroid observations (Duffard et al., 2004). In this work, we present spectra of V type asteroids. Asteroids belonging to the Vesta family and those classified as non-Vesta family are compared, in order to point out similarities and differences. Results are based on observations obtained with the Telescopio Nazionale Galileo, a 3.5m-telescope in LaPalma. The proposed work is intended to support the future observations of 4Vesta, by DAWN.</p> </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"><span>20</span></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><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <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"><span>21</span></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> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009eso..pres...16.','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009eso..pres...16."><span>Solar wind tans young asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p></p> <p>2009-04-01</p> <p>A new study published in Nature this week reveals that asteroid surfaces age and redden much faster than previously thought -- in less than a million years, the blink of an eye for an asteroid. This study has finally confirmed that the solar wind is the most likely cause of very rapid space weathering in asteroids. This fundamental result will help astronomers relate the appearance of an asteroid to its actual history and identify any after effects of a catastrophic impact with another asteroid. ESO PR Photo 16a/09 Young Asteroids Look Old "Asteroids seem to get a ‘sun tan' very quickly," says lead author Pierre Vernazza. "But not, as for people, from an overdose of the Sun's ultraviolet radiation, but from the effects of its powerful wind." It has long been known that asteroid surfaces alter in appearance with time -- the observed asteroids are much redder than the interior of meteorites found on Earth [1] -- but the actual processes of this "space weathering" and the timescales involved were controversial. Thanks to observations of different families of asteroids [2] using ESO's New Technology Telescope at La Silla and the Very Large Telescope at Paranal, as well as telescopes in Spain and Hawaii, Vernazza's team have now solved the puzzle. When two asteroids collide, they create a family of fragments with "fresh" surfaces. The astronomers found that these newly exposed surfaces are quickly altered and change colour in less than a million years -- a very short time compared to the age of the Solar System. "The charged, fast moving particles in the solar wind damage the asteroid's surface at an amazing rate [3]", says Vernazza. Unlike human skin, which is damaged and aged by repeated overexposure to sunlight, it is, perhaps rather surprisingly, the first moments of exposure (on the timescale considered) -- the first million years -- that causes most of the aging in asteroids. By studying different families of asteroids, the team has also shown that an asteroid's surface composition is an important factor in how red its surface can become. After the first million years, the surface "tans" much more slowly. At that stage, the colour depends more on composition than on age. Moreover, the observations reveal that collisions cannot be the main mechanism behind the high proportion of "fresh" surfaces seen among near-Earth asteroids. Instead, these "fresh-looking" surfaces may be the results of planetary encounters, where the tug of a planet has "shaken" the asteroid, exposing unaltered material. Thanks to these results, astronomers will now be able to understand better how the surface of an asteroid -- which often is the only thing we can observe -- reflects its history. More information This result was presented in a paper published this week in the journal Nature, "Solar wind as the origin of rapid reddening of asteroid surfaces", by P. Vernazza et al. The team is composed of Pierre Vernazza (ESA), Richard Binzel (MIT, Cambridge, USA), Alessandro Rossi (ISTI-CNR, Pisa, Italy), Marcello Fulchignoni (Paris Observatory, France), and Mirel Birlan (IMCCE, CNRS-8028, Paris Observatory, France). A PDF file can be downloaded here. Notes [1] Meteorites are small fragments of asteroids that fall on Earth. While a meteorite enters the Earth's atmosphere its surface can melt and be partially charred by the intense heat. Nevertheless, the meteorite interior remains unaffected, and can be studied in a laboratory, providing a wealth of information on the nature and composition of asteroids. [2] An asteroid family is a group of asteroids that are on similar orbits around the Sun. The members of a given family are believed to be the fragments of a larger asteroid that was destroyed during a collision. [3] The surface of an asteroid is affected by the highly energetic particles forming the solar wind. These particles partially destroy the molecules and crystals on the surface, re-arranging them in other combinations. Over time, these changes give formation of a thin crust or irradiated material with distinct colours and properties.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20000075265&hterms=steroids&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsteroids','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20000075265&hterms=steroids&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsteroids"><span>Determination of Eros Physical Parameters for Near Earth Asteroid Rendezvous Orbit Phase Navigation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Miller, J. K.; Antreasian, P. J.; Georgini, J.; Owen, W. M.; Williams, B. G.; Yeomans, D. K.</p> <p>1995-01-01</p> <p>Navigation of the orbit phase of the Near Earth steroid Rendezvous (NEAR) mission will re,quire determination of certain physical parameters describing the size, shape, gravity field, attitude and inertial properties of Eros. Prior to launch, little was known about Eros except for its orbit which could be determined with high precision from ground based telescope observations. Radar bounce and light curve data provided a rough estimate of Eros shape and a fairly good estimate of the pole, prime meridian and spin rate. However, the determination of the NEAR spacecraft orbit requires a high precision model of Eros's physical parameters and the ground based data provides only marginal a priori information. Eros is the principal source of perturbations of the spacecraft's trajectory and the principal source of data for determining the orbit. The initial orbit determination strategy is therefore concerned with developing a precise model of Eros. The original plan for Eros orbital operations was to execute a series of rendezvous burns beginning on December 20,1998 and insert into a close Eros orbit in January 1999. As a result of an unplanned termination of the rendezvous burn on December 20, 1998, the NEAR spacecraft continued on its high velocity approach trajectory and passed within 3900 km of Eros on December 23, 1998. The planned rendezvous burn was delayed until January 3, 1999 which resulted in the spacecraft being placed on a trajectory that slowly returns to Eros with a subsequent delay of close Eros orbital operations until February 2001. The flyby of Eros provided a brief glimpse and allowed for a crude estimate of the pole, prime meridian and mass of Eros. More importantly for navigation, orbit determination software was executed in the landmark tracking mode to determine the spacecraft orbit and a preliminary shape and landmark data base has been obtained. The flyby also provided an opportunity to test orbit determination operational procedures that will be used in February of 2001. The initial attitude and spin rate of Eros, as well as estimates of reference landmark locations, are obtained from images of the asteroid. These initial estimates are used as a priori values for a more precise refinement of these parameters by the orbit determination software which combines optical measurements with Doppler tracking data to obtain solutions for the required parameters. As the spacecraft is maneuvered; closer to the asteroid, estimates of spacecraft state, asteroid attitude, solar pressure, landmark locations and Eros physical parameters including mass, moments of inertia and gravity harmonics are determined with increasing precision. The determination of the elements of the inertia tensor of the asteroid is critical to spacecraft orbit determination and prediction of the asteroid attitude. The moments of inertia about the principal axes are also of scientific interest since they provide some insight into the internal mass distribution. Determination of the principal axes moments of inertia will depend on observing free precession in the asteroid's attitude dynamics. Gravity harmonics are in themselves of interest to science. When compared with the asteroid shape, some insight may be obtained into Eros' internal structure. The location of the center of mass derived from the first degree harmonic coefficients give a direct indication of overall mass distribution. The second degree harmonic coefficients relate to the radial distribution of mass. Higher degree harmonics may be compared with surface features to gain additional insight into mass distribution. In this paper, estimates of Eros physical parameters obtained from the December 23,1998 flyby will be presented. This new knowledge will be applied to simplification of Eros orbital operations in February of 2001. The resulting revision to the orbit determination strategy will also be discussed.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017CeMDA.129...57T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017CeMDA.129...57T"><span>Direct and indirect capture of near-Earth asteroids in the Earth-Moon system</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tan, Minghu; McInnes, Colin; Ceriotti, Matteo</p> <p>2017-09-01</p> <p>Near-Earth asteroids have attracted attention for both scientific and commercial mission applications. Due to the fact that the Earth-Moon L1 and L2 points are candidates for gateway stations for lunar exploration, and an ideal location for space science, capturing asteroids and inserting them into periodic orbits around these points is of significant interest for the future. In this paper, we define a new type of lunar asteroid capture, termed direct capture. In this capture strategy, the candidate asteroid leaves its heliocentric orbit after an initial impulse, with its dynamics modeled using the Sun-Earth-Moon restricted four-body problem until its insertion, with a second impulse, onto the L2 stable manifold in the Earth-Moon circular restricted three-body problem. A Lambert arc in the Sun-asteroid two-body problem is used as an initial guess and a differential corrector used to generate the transfer trajectory from the asteroid's initial obit to the stable manifold associated with Earth-Moon L2 point. Results show that the direct asteroid capture strategy needs a shorter flight time compared to an indirect asteroid capture, which couples capture in the Sun-Earth circular restricted three-body problem and subsequent transfer to the Earth-Moon circular restricted three-body problem. Finally, the direct and indirect asteroid capture strategies are also applied to consider capture of asteroids at the triangular libration points in the Earth-Moon system.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26887492','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26887492"><span>Super-catastrophic disruption of asteroids at small perihelion distances.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Granvik, Mikael; Morbidelli, Alessandro; Jedicke, Robert; Bolin, Bryce; Bottke, William F; Beshore, Edward; Vokrouhlický, David; Delbò, Marco; Michel, Patrick</p> <p>2016-02-18</p> <p>Most near-Earth objects came from the asteroid belt and drifted via non-gravitational thermal forces into resonant escape routes that, in turn, pushed them onto planet-crossing orbits. Models predict that numerous asteroids should be found on orbits that closely approach the Sun, but few have been seen. In addition, even though the near-Earth-object population in general is an even mix of low-albedo (less than ten per cent of incident radiation is reflected) and high-albedo (more than ten per cent of incident radiation is reflected) asteroids, the characterized asteroids near the Sun typically have high albedos. Here we report a quantitative comparison of actual asteroid detections and a near-Earth-object model (which accounts for observational selection effects). We conclude that the deficit of low-albedo objects near the Sun arises from the super-catastrophic breakup (that is, almost complete disintegration) of a substantial fraction of asteroids when they achieve perihelion distances of a few tens of solar radii. The distance at which destruction occurs is greater for smaller asteroids, and their temperatures during perihelion passages are too low for evaporation to explain their disappearance. Although both bright and dark (high- and low-albedo) asteroids eventually break up, we find that low-albedo asteroids are more likely to be destroyed farther from the Sun, which explains the apparent excess of high-albedo near-Earth objects and suggests that low-albedo asteroids break up more easily as a result of thermal effects.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DPS....4730701H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DPS....4730701H"><span>A path to asteroid bulk densities: Simultaneous size and shape optimization from optical lightcurves and Keck disk-resolved data</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hanus, Josef; Viikinkoski, Matti; Marchis, Franck; Durech, Josef</p> <p>2015-11-01</p> <p>A reliable bulk density of an asteroid can be determined from the knowledge of its volume and mass. This quantity provides hints on the internal structure of asteroids and their origin. We compute volume of several asteroids by scaling sizes of their 3D shape models to fit the disk-resolved images, which are available in the Keck Observatory Archive (KOA) and the Virtual Observatory Binary Asteroids Database (VOBAD). The size of an asteroid is optimized together with its shape by the All-Data Asteroid Modelling inversion algorithm (ADAM, Viikinkoski et al., 2015, A&A, 576, A8), while the spin state of the original convex shape model from the DAMIT database is only used as an initial guess for the modeling. Updated sets of optical lightcurves are usually employed. Thereafter, we combine obtained volume with mass estimates available in the literature and derive bulk densities for tens of asteroids with a typical accuracy of 20-50%.On top of that, we also provide a list of asteroids, for which (i) there are already mass estimates with reported uncertainties better than 20% or their masses will be most likely determined in the future from Gaia astrometric observations, and (ii) their 3D shape models are currently unknown. Additional optical lightcurves are necessary in order to determine convex shape models of these asteroids. Our web page (https://asteroid-obs.oca.eu/foswiki/bin/view/Main/Photometry) contains additional information about this observation campaign.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011Icar..214..161J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011Icar..214..161J"><span>Dynamics of rotationally fissioned asteroids: Source of observed small asteroid systems</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jacobson, Seth A.; Scheeres, Daniel J.</p> <p>2011-07-01</p> <p>We present a model of near-Earth asteroid (NEA) rotational fission and ensuing dynamics that describes the creation of synchronous binaries and all other observed NEA systems including: doubly synchronous binaries, high- e binaries, ternary systems, and contact binaries. Our model only presupposes the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect, "rubble pile" asteroid geophysics, and gravitational interactions. The YORP effect torques a "rubble pile" asteroid until the asteroid reaches its fission spin limit and the components enter orbit about each other (Scheeres, D.J. [2007]. Icarus 189, 370-385). Non-spherical gravitational potentials couple the spin states to the orbit state and chaotically drive the system towards the observed asteroid classes along two evolutionary tracks primarily distinguished by mass ratio. Related to this is a new binary process termed secondary fission - the secondary asteroid of the binary system is rotationally accelerated via gravitational torques until it fissions, thus creating a chaotic ternary system. The initially chaotic binary can be stabilized to create a synchronous binary by components of the fissioned secondary asteroid impacting the primary asteroid, solar gravitational perturbations, and mutual body tides. These results emphasize the importance of the initial component size distribution and configuration within the parent asteroid. NEAs may go through multiple binary cycles and many YORP-induced rotational fissions during their approximately 10 Myr lifetime in the inner Solar System. Rotational fission and the ensuing dynamics are responsible for all NEA systems including the most commonly observed synchronous binaries.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2013-05-28/pdf/2013-12547.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2013-05-28/pdf/2013-12547.pdf"><span>78 FR 31977 - NASA Asteroid Initiative Call for Ideas</span></a></p> <p><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></p> <p></p> <p>2013-05-28</p> <p>... NATIONAL AERONAUTICS AND SPACE ADMINISTRATION [Notice: 13-060] NASA Asteroid Initiative Call for... agency's asteroid initiative planning and to encourage feedback and ideas from the global community and... Perspective--Tom Kalil 9:55-10:15 Asteroid Initiative--Associate Administrator Lightfoot [[Page 31978</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19890025268&hterms=nolan&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dnolan','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19890025268&hterms=nolan&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dnolan"><span>Asteroid/comet encounter opportunities for the Galileo VEEGA mission</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Johannesen, Jennie R.; Nolan, Brian G.; Byrnes, Dennis V.; D'Amario, Louis A.</p> <p>1988-01-01</p> <p>The opportunity for the Galileo spacecraft to perform a close flyby of an asteroid or distant observation of a comet while on the Venus-Earth-Earth-Gravity-Assist (VEEGA) mission to Jupiter is discussed. More than 120 nominal trajectories were used in a scan program to identify asteroids passing within 30 million km of the spacecraft. A total of 47 asteroids were examined to determine the propellant cost of a close flyby. The possible flybys include a double asteroid flyby with No. 951 in October, 1991, with a flyby of No. 243 in August 1993. The factors considered in the selection of an asteroid include the propellant margin cost of modifying a nominal trajectory to include a close flyby, the size and type of asteroid, and the Jupiter arrival date.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.P23A2711C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.P23A2711C"><span>Geophysical Evolution of Ch Asteroids and Testable Hypotheses for Future Missions</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Castillo, J. C.</p> <p>2017-12-01</p> <p>The main population of asteroids related to meteorites in the collections remains to be explored in situ. Ch asteroids are the only midsized asteroids that display a signature of hydration (besides Pallas) and the spectral connection between Ch asteroids and CM chondrites suggests that the former represent potential parent bodies for the latter. This class of asteroids is particularly interesting because it hosts many objects 100-200 km in size, which are believed to belong to a primordial population of planetesimals. This presentation will explore multiple evolution pathways for Ch-asteroids leading to possible hypotheses on the geological, petrological, and geophysical properties that a disrupted parent body would present to a future mission. This work is being carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1985Icar...62..305B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1985Icar...62..305B"><span>Ultraviolet reflectance properties of asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Butterworth, P. S.; Meadows, A. J.</p> <p>1985-05-01</p> <p>An analysis of the UV spectra of 28 asteroids obtained with the Internal Ultraviolet Explorer (IUE) satellite is presented. The spectra lie within the range 2100-3200 A. The results are examined in terms of both asteroid classification and of current ideas concerning the surface mineralogy of asteroids. For all the asteroids examined, UV reflectivity declines approximately linearly toward shorter wavelengths. In general, the same taxonomic groups are seen in the UV as in the visible and IR, although there is some evidence for asteroids with anomalous UV properties and for UV subclasses within the S class. No mineral absorption features are reported of strength similar to the strongest features in the visible and IR regions, but a number of shallow absorptions do occur and may provide valuable information on the surface composition of many asteroids.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014acm..conf..483S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014acm..conf..483S"><span>Origin of igneous meteorites and differentiated asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Scott, E.; Goldstein, J.; Asphaug, E.; Bottke, W.; Moskovitz, N.; Keil, K.</p> <p>2014-07-01</p> <p>Introduction: Igneously formed meteorites and asteroids provide major challenges to our understanding of the formation and evolution of the asteroid belt. The numbers and types of differentiated meteorites and non-chondritic asteroids appear to be incompatible with an origin by fragmentation of numerous Vesta-like bodies by hypervelocity impacts in the asteroid belt over 4 Gyr. We lack asteroids and achondrites from the olivine-rich mantles of the parent bodies of the 12 groups of iron meteorites and the ˜70 ungrouped irons, the 2 groups of pallasites and the 4--6 ungrouped pallasites. We lack mantle and core samples from the parent asteroids of the basaltic achondrites that do not come from Vesta, viz., angrites and the ungrouped eucrites like NWA 011 and Ibitira. How could core samples have been extracted from numerous differentiated bodies when Vesta's basaltic crust was preserved? Where is the missing Psyche family of differentiated asteroids including the complementary mantle and crustal asteroids [1]? Why are meteorites derived from far more differentiated parent bodies than chondritic parent bodies even though C and S class chondritic asteroids dominate the asteroid belt? New paradigm. Our studies of meteorites, impact modeling, and dynamical studies suggest a new paradigm in which differentiated asteroids accreted at 1--2 au less than 2 Myr after CAI formation [2]. They were rapidly melted by 26Al and disrupted by hit-and-run impacts [3] while still molten or semi-molten when planetary embryos were accreting. Metallic Fe-Ni bodies derived from core material cooled rapidly with little or no silicate insulation less than 4 Myr after CAI formation [4]. Fragments of differentiated planetesimals were subsequently tossed into the asteroid belt. Meteorite evidence for early disruption of differentiated asteroids. If iron meteorites were samples of Fe-Ni cores of bodies that cooled slowly inside silicate mantles over ˜50--100 Myr, irons from each core would have almost indistinguishable cooling rates as thermal gradients across cores would have been minimal. Irons in groups IIIAB, IVA, and IVB have chemical crystallization trends showing that they cooled in three separate bodies. However, each shows a wide range of cooling rates [4]. Group IVA irons cooled through 500°C at 6600--100 °C/Myr in a metallic body of radius 150 ± 50 km with scarcely any silicate insulation [5]. The Pb-Pb age of 4565.3 ± 0.1 Myr for a IVA iron [6] confirms that these irons cooled to ˜300°C only 2--3 Myr after CAI formation. Multiple hit-and-run impacts may have separated core and mantle material during accretion [7] as hypervelocity impacts do not efficiently separate cores from mantles. Thermal histories and magnetic properties of main group pallasites also require early catastrophic disruption of their primary parent body [8,9]. Conclusions. The anomalous properties of differentiated asteroids and meteorites cannot be explained by concealing differentiated planetesimals under chondritic crusts [10] as meteorite breccias and the apparent compositional homogeneity of asteroid families are inconsistent with this model. Like Burbine et al. [11], we attribute the lack of olivine mantle meteorites and asteroids to collisional grinding of weaker silicate and the preferential survival of stronger metallic Fe,Ni fragments. But we infer that asteroid break up occurred very early inside 2 au, not in the asteroid belt over 4 Gyr. Vesta may have preserved its crust due to early ejection into the asteroid belt. It is the smallest terrestrial planet --- not an archetypal differentiated asteroid.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20130013405','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20130013405"><span>Conceptual Design of a Hypervelocity Asteroid Intercept Vehicle (HAIV) Flight Validation Mission</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Barbee, Brent W.; Wie, Bong; Steiner, Mark; Getzandanner, Kenneth</p> <p>2013-01-01</p> <p>In this paper we present a detailed overview of the MDL study results and subsequent advances in the design of GNC algorithms for accurate terminal guidance during hypervelocity NEO intercept. The MDL study produced a conceptual con guration of the two-body HAIV and its subsystems; a mission scenario and trajectory design for a notional flight validation mission to a selected candidate target NEO; GNC results regarding the ability of the HAIV to reliably intercept small (50 m) NEOs at hypervelocity (typically greater than 10 km/s); candidate launch vehicle selection; a notional operations concept and cost estimate for the flight validation mission; and a list of topics to address during the remainder of our NIAC Phase II study.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017DPS....4911019D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017DPS....4911019D"><span>Bayesian modeling of the mass and density of asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dotson, Jessie L.; Mathias, Donovan</p> <p>2017-10-01</p> <p>Mass and density are two of the fundamental properties of any object. In the case of near earth asteroids, knowledge about the mass of an asteroid is essential for estimating the risk due to (potential) impact and planning possible mitigation options. The density of an asteroid can illuminate the structure of the asteroid. A low density can be indicative of a rubble pile structure whereas a higher density can imply a monolith and/or higher metal content. The damage resulting from an impact of an asteroid with Earth depends on its interior structure in addition to its total mass, and as a result, density is a key parameter to understanding the risk of asteroid impact. Unfortunately, measuring the mass and density of asteroids is challenging and often results in measurements with large uncertainties. In the absence of mass / density measurements for a specific object, understanding the range and distribution of likely values can facilitate probabilistic assessments of structure and impact risk. Hierarchical Bayesian models have recently been developed to investigate the mass - radius relationship of exoplanets (Wolfgang, Rogers & Ford 2016) and to probabilistically forecast the mass of bodies large enough to establish hydrostatic equilibrium over a range of 9 orders of magnitude in mass (from planemos to main sequence stars; Chen & Kipping 2017). Here, we extend this approach to investigate the mass and densities of asteroids. Several candidate Bayesian models are presented, and their performance is assessed relative to a synthetic asteroid population. In addition, a preliminary Bayesian model for probablistically forecasting masses and densities of asteroids is presented. The forecasting model is conditioned on existing asteroid data and includes observational errors, hyper-parameter uncertainties and intrinsic scatter.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1258524','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1258524"><span>Deflection by kinetic impact: Sensitivity to asteroid properties</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Bruck Syal, Megan; Michael Owen, J.; Miller, Paul L.</p> <p></p> <p>Impacting an asteroid with a spacecraft traveling at high speed delivers an impulsive change in velocity to the body. In certain circumstances, this strategy could be used to deflect a hazardous asteroid, moving its orbital path off of an Earth-impacting course. However, the efficacy of momentum delivery to asteroids by hypervelocity impact is sensitive to both the impact conditions (particularly velocity) and specific characteristics of the target asteroid. We numerically model asteroid response to kinetic impactors under a wide range of initial conditions, using an Adaptive Smoothed Particle Hydrodynamics code. Impact velocities spanning 1–30 km/s were investigated, yielding, for amore » particular set of assumptions about the modeled target material, a power-law dependence consistent with a velocity-scaling exponent of μ = 0.44. Target characteristics including equation of state, strength model, porosity, rotational state, and shape were varied, and corresponding changes in asteroid response were documented. Moreover, the kinetic-impact momentum-multiplication factor, β, decreases with increasing asteroid cohesion and increasing porosity. Although increased porosity lowers β, larger porosities result in greater deflection velocities, as a consequence of reduced target masses for asteroids of fixed size. Porosity also lowers disruption risk for kinetic impacts near the threshold of disruption. Including fast (P = 2.5 h) and very fast (P = 100 s) rotation did not significantly alter β but did affect the risk of disruption by the impact event. Asteroid shape is found to influence the efficiency of momentum delivery, as local slope conditions can change the orientation of the crater ejecta momentum vector. Our results emphasize the need for asteroid characterization studies to bracket the range of target conditions expected at near-Earth asteroids while also highlighting some of the principal uncertainties associated with the kinetic-impact deflection strategy.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017DPS....4920106S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017DPS....4920106S"><span>Asteroid mass estimation with Markov-chain Monte Carlo</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Siltala, Lauri; Granvik, Mikael</p> <p>2017-10-01</p> <p>Estimates for asteroid masses are based on their gravitational perturbations on the orbits of other objects such as Mars, spacecraft, or other asteroids and/or their satellites. In the case of asteroid-asteroid perturbations, this leads to a 13-dimensional inverse problem at minimum where the aim is to derive the mass of the perturbing asteroid and six orbital elements for both the perturbing asteroid and the test asteroid by fitting their trajectories to their observed positions. The fitting has typically been carried out with linearized methods such as the least-squares method. These methods need to make certain assumptions regarding the shape of the probability distributions of the model parameters. This is problematic as these assumptions have not been validated. We have developed a new Markov-chain Monte Carlo method for mass estimation which does not require an assumption regarding the shape of the parameter distribution. Recently, we have implemented several upgrades to our MCMC method including improved schemes for handling observational errors and outlier data alongside the option to consider multiple perturbers and/or test asteroids simultaneously. These upgrades promise significantly improved results: based on two separate results for (19) Fortuna with different test asteroids we previously hypothesized that simultaneous use of both test asteroids would lead to an improved result similar to the average literature value for (19) Fortuna with substantially reduced uncertainties. Our upgraded algorithm indeed finds a result essentially equal to the literature value for this asteroid, confirming our previous hypothesis. Here we show these new results for (19) Fortuna and other example cases, and compare our results to previous estimates. Finally, we discuss our plans to improve our algorithm further, particularly in connection with Gaia.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017DPS....4911018W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017DPS....4911018W"><span>Sensitivity of Asteroid Impact Risk to Uncertainty in Asteroid Properties and Entry Parameters</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wheeler, Lorien; Mathias, Donovan; Dotson, Jessie L.; NASA Asteroid Threat Assessment Project</p> <p>2017-10-01</p> <p>A central challenge in assessing the threat posed by asteroids striking Earth is the large amount of uncertainty inherent throughout all aspects of the problem. Many asteroid properties are not well characterized and can range widely from strong, dense, monolithic irons to loosely bound, highly porous rubble piles. Even for an object of known properties, the specific entry velocity, angle, and impact location can swing the potential consequence from no damage to causing millions of casualties. Due to the extreme rarity of large asteroid strikes, there are also large uncertainties in how different types of asteroids will interact with the atmosphere during entry, how readily they may break up or ablate, and how much surface damage will be caused by the resulting airbursts or impacts.In this work, we use our Probabilistic Asteroid Impact Risk (PAIR) model to investigate the sensitivity of asteroid impact damage to uncertainties in key asteroid properties, entry parameters, or modeling assumptions. The PAIR model combines physics-based analytic models of asteroid entry and damage in a probabilistic Monte Carlo framework to assess the risk posed by a wide range of potential impacts. The model samples from uncertainty distributions of asteroid properties and entry parameters to generate millions of specific impact cases, and models the atmospheric entry and damage for each case, including blast overpressure, thermal radiation, tsunami inundation, and global effects. To assess the risk sensitivity, we alternately fix and vary the different input parameters and compare the effect on the resulting range of damage produced. The goal of these studies is to help guide future efforts in asteroid characterization and model refinement by determining which properties most significantly affect the potential risk.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1258524-deflection-kinetic-impact-sensitivity-asteroid-properties','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1258524-deflection-kinetic-impact-sensitivity-asteroid-properties"><span>Deflection by kinetic impact: Sensitivity to asteroid properties</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Bruck Syal, Megan; Michael Owen, J.; Miller, Paul L.</p> <p>2016-05-01</p> <p>Impacting an asteroid with a spacecraft traveling at high speed delivers an impulsive change in velocity to the body. In certain circumstances, this strategy could be used to deflect a hazardous asteroid, moving its orbital path off of an Earth-impacting course. However, the efficacy of momentum delivery to asteroids by hypervelocity impact is sensitive to both the impact conditions (particularly velocity) and specific characteristics of the target asteroid. We numerically model asteroid response to kinetic impactors under a wide range of initial conditions, using an Adaptive Smoothed Particle Hydrodynamics code. Impact velocities spanning 1–30 km/s were investigated, yielding, for amore » particular set of assumptions about the modeled target material, a power-law dependence consistent with a velocity-scaling exponent of μ = 0.44. Target characteristics including equation of state, strength model, porosity, rotational state, and shape were varied, and corresponding changes in asteroid response were documented. Moreover, the kinetic-impact momentum-multiplication factor, β, decreases with increasing asteroid cohesion and increasing porosity. Although increased porosity lowers β, larger porosities result in greater deflection velocities, as a consequence of reduced target masses for asteroids of fixed size. Porosity also lowers disruption risk for kinetic impacts near the threshold of disruption. Including fast (P = 2.5 h) and very fast (P = 100 s) rotation did not significantly alter β but did affect the risk of disruption by the impact event. Asteroid shape is found to influence the efficiency of momentum delivery, as local slope conditions can change the orientation of the crater ejecta momentum vector. Our results emphasize the need for asteroid characterization studies to bracket the range of target conditions expected at near-Earth asteroids while also highlighting some of the principal uncertainties associated with the kinetic-impact deflection strategy.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940011701','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940011701"><span>Spectral evidence of size dependent space weathering processes on asteroid surfaces</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gaffey, M. J.; Bell, J. F.; Brown, R. H.; Burbine, T. H.; Piatek, J. L.; Reed, K. L.; Chaky, D. A.</p> <p>1993-01-01</p> <p>Most compositional characterizations of the minor planets are derived from analysis of visible and near-infrared reflectance spectra. However, such spectra are derived from light which has only interacted with a very thin surface layer. Although regolith processes are assumed to mix all near-surface lithologic units into this layer, it has been proposed that space weathering processes can alter this surface layer to obscure the spectral signature of the bedrock lithology. It has been proposed that these spectral alteration processes are much less pronounced on asteroid surfaces than on the lunar surface, but the possibility of major spectral alteration of asteroidal optical surfaces has been invoked to reconcile S-asteroids with ordinary chondrites. The reflectance spectra of a large subset of the S-asteroid population have been analyzed in a systematic investigation of the mineralogical diversity within the S-class. In this sample, absorption band depth is a strong function of asteroid diameter. The S-asteroid band depths are relatively constant for objects larger than 100 km and increase linearly by factor of two toward smaller sizes (approximately 40 km). Although the S-asteroid surface materials includes a diverse variety of silicate assemblages, ranging from dunites to basalts, all compositional subtypes of the S-asteroids conform to this trend. The A-, R-, and V-type asteroids which are primarily silicate assemblages (as opposed to the metal-silicate mixtures of most S-asteroids) follow a parallel but displaced trend. Some sort of textural or regolith equilibrium appears to have been attained in the optical surfaces of asteroids larger than about 100 km diameter but not on bodies below this size. The relationships between absorption band depth, spectral slope, surface albedo and body size provide an intriguing insight into the nature of the optical surfaces of the S-asteroids and space weathering on these objects.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E1861S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E1861S"><span>"Prospecting Asteroids: Indirect technique to estimate overall density and inner composition"</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Such, Pamela</p> <p>2016-07-01</p> <p>Spectroscopic studies of asteroids make possible to obtain some information on their composition from the surface but say little about the innermost material, porosity and density of the object. In addition, spectroscopic observations are affected by the effects of "space weathering" produced by the bombardment of charged particles for certain materials that change their chemical structure, albedo and other physical properties, partly altering their chances of identification. Data such as the mass, size and density of the asteroids are essential at the time to propose space missions in order to determine the best candidates for space exploration and is of great importance to determine a priori any of them remotely from Earth. From many years ago its determined masses of largest asteroids studying the gravitational effects they have on smaller asteroids when they approach them (see Davis and Bender, 1977; Schubart and Matson, 1979; School et al 1987; Hoffman, 1989b, among others), but estimates of the masses of the smallest objects is limited to the effects that occur in extreme close encounters to other asteroids of similar size. This paper presents the results of a search for approaches of pair of asteroids that approximate distances less than 0.0004 UA (50,000 km) of each other in order to study their masses through the astrometric method and to estimate in a future their densities and internal composition. References Davis, D. R., and D. F. Bender. 1977. Asteroid mass determinations: search for futher encounter opportunities. Bull. Am. Astron. Soc. 9, 502-503. Hoffman, M. 1989b. Asteroid mass determination: Present situation and perspectives. In asteroids II (R. P. Binzel, T. Gehreis, and M. S. Matthews, Eds.), pp 228-239. Univ. Arizona Press, Tucson. School, H. L. D. Schmadel and S. Roser 1987. The mass of the asteroid (10) Hygiea derived from observations of (829) Academia. Astron. Astrophys. 179, 311-316. Schubart, J. And D. L. Matson 1979. Masses and densities of asteroids. In Asteroids (T. Gehrels, Ed.), pp.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015nova.pres..121K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015nova.pres..121K"><span>Discovery of a New Super-Fast Rotator</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kohler, Susanna</p> <p>2015-07-01</p> <p>Recent observations of asteroid (335433) 2005 UW163 have added a new member to the mysterious category of "super-fast rotators" — asteroids that rotate faster than should be possible, given current theories of asteroid composition. Asteroids come in sizes of a few meters to a few hundred kilometers, and can spin at rates from 0.1 to nearly 1000 revolutions per day. Current theories suggest that asteroids smaller than 150m are mostly monolithic (made up of a single rock), whereas asteroids larger than 150m are usually what's known as a "rubble pile" — a collection of rock fragments from past collisions, bound together into a clump by gravity. "Rubble pile" asteroids have an important structural limitation: they can't spin faster than once every 2.2 hours without flying apart as the centripetal force overcomes the force of gravity. Asteroid 2005 UW163 violates this rule: its diameter is 690m, but it rotates once every 1.29 hours. This discovery was made by a team of scientists using telescopes at the Palomar Observatory in California to conduct a large survey of the rotation rates of nearby asteroids. The group, led by Chan-Kao Chang of Taiwan's National Central University, discovered 11 super-fast rotator candidates — of which asteroid 2005 UW163 is the first to have its rotation rate confirmed by additional observations. The category of super-fast rotators poses an interesting problem: how are they able to spin so quickly without flying apart? Either the density of these asteroids is unexpectedly high (roughly four times the density of typical "rubble pile" asteroids), or else there must be additional forces besides gravity at work to help hold the asteroid together, such as bonds between the rocks. Future observations of super-fast rotators will help us better understand the peculiar structure of these rocky neighbors. Citation: Chan-Kao Chang et al. 2014 ApJ 791 L35 doi:10.1088/2041-8205/791/2/L35</p> </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"><span>21</span></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><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <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"><span>22</span></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> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2013-08-21/pdf/2013-20353.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2013-08-21/pdf/2013-20353.pdf"><span>78 FR 51750 - NASA Asteroid Initiative Idea Synthesis Workshop</span></a></p> <p><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></p> <p></p> <p>2013-08-21</p> <p>... NATIONAL AERONAUTICS AND SPACE ADMINISTRATION [Notice: 13-096] NASA Asteroid Initiative Idea... Conference to examine ideas in response to the recent RFI for the agency's Asteroid Initiative. SUMMARY: The... Agency's Asteroid Initiative planning and to enable feedback and discussion from the global community and...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018IAUS..330..386I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018IAUS..330..386I"><span>Prospects for asteroid mass determination from close encounters between asteroids: ESA's Gaia space mission and beyond</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ivantsov, Anatoliy; Hestroffer, Daniel; Eggl, Siegfried</p> <p>2018-04-01</p> <p>We present a catalog of potential candidates for asteroid mass determination based on mutual close encounters of numbered asteroids with massive perturbers (D>20 km). Using a novel geometric approach tuned to optimize observability, we predict optimal epochs for mass determination observations. In contrast to previous studies that often used simplified dynamical models, we have numerically propagated the trajectories of all numbered asteroids over the time interval from 2013 to 2023 using relativistic equations of motion including planetary perturbations, J2 of the Sun, the 16 major asteroid perturbers and the perturbations due to non-sphericities of the planets. We compiled a catalog of close encounters between asteroids where the observable perturbation of the sky plane trajectory is greater than 0.5 mas so that astrometric measurements of the perturbed asteroids in the Gaia data can be leveraged. The catalog v1.0 is available at ftp://dosya.akdeniz.edu.tr/ivantsov.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020094334','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020094334"><span>Asteroid Size-Frequency Distribution</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tedesco, Edward F.</p> <p>2001-01-01</p> <p>A total of six deep exposures (using AOT CAM01 with a 6 inch PFOV) through the ISOCAM LW10 filter (IRAS Band 1, i.e. 12 micron) were obtained on an approximately 15 arcminute square field centered on the ecliptic plane. Point sources were extracted using the technique described. Two known asteroids appear in these frames and 20 sources moving with velocities appropriate for main belt asteroids are present. Most of the asteroids detected have flux densities less than 1 mJy, i,e., between 150 and 350 times fainter than any of the asteroids observed by IRAS. These data provide the first direct measurement of the 12 pm sky-plane density for asteroids on the ecliptic equator. The median zodiacal foreground, as measured by ISOCAM during this survey, is found to be 22.1 +/- 1.5 mJy per pixel, i.e., 26.2 +/- 1.7 MJy/sr. The results presented here imply that the actual number of kilometer-sized asteroids is significantly greater than previously believed and in reasonable agreement with the Statistical Asteroid Model.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040059594&hterms=purpose+science&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dpurpose%2Bscience','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040059594&hterms=purpose+science&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dpurpose%2Bscience"><span>Sample Return Science by Hayabusa Near-Earth Asteroid Mission</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fujiwara, A.; Abe, M.; Kato, M.; Kushiro, I.; Mukai, T.; Okada, T.; Saito, J.; Sasaki, S.; Yano, H.; Yeomans, D.</p> <p>2004-01-01</p> <p>Assigning the material species to each asteroid spectral type and finding out the corresponding meteorite category is crucial to make the global material map in the whole asteroid belt and to understand the evolution of the asteroid belt. Recent direct observations by spacecrafts are revealing new intriguing aspects of asteroids which cannot be obtained solely from ground-based observations or meteorite studies. However identification of the real material species constituting asteroids and their corresponding meteorite analogs are still ambiguous. Space weathering makes difficult to identify the true material, and there is still a great gap between the remote sensing data on the global surface and the local microscopic data from meteorites. Sample return from asteroids are inevitable to solve these problems. For this purpose sample return missions to asteroids belonging to various spectral classes are required. The HAYABUSA spacecraft (prelaunch name is MUSESC) launched last year is the first attempt on this concept. This report presents outline of the mission with special stress on its science.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005Icar..174...46S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005Icar..174...46S"><span>Meteoritic and other constraints on the internal structure and impact history of small asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Scott, Edward R. D.; Wilson, Lionel</p> <p>2005-03-01</p> <p>Studies of the internal structure of asteroids, which are crucial for understanding their impact history and for hazard mitigation, appear to be in conflict for the S-type asteroids, Eros, Gaspra, and Ida. Spacecraft images and geophysical data show that they are fractured, coherent bodies, whereas models of catastrophic asteroidal impacts, family and satellite formation, and studies of asteroid spin rates, and other diverse properties of asteroids and planetary craters suggest that such asteroids are gravitationally bound aggregates of rubble. These conflicting views may be reconciled if 10-50 km S-type asteroids formed as rubble piles, but were later consolidated into coherent bodies. Many meteorites are breccias that testify to a long history of impact fragmentation and consolidation by alteration, metamorphism, igneous and impact processes. Ordinary chondrites, which are the best analogs for S asteroids, are commonly breccias. Some may have formed in cratering events, but many appear to have formed during disruption and reaccretion of their parent asteroids. Some breccias were lithified during metamorphism, and a few were lithified by injected impact melt, but most are regolith and fragmental breccias that were lithified by mild or moderate shock, like their lunar analogs. Shock experiments show that porous chondritic powders can be consolidated during mild shock by small amounts of silicate melt that glues grains together, and by friction and pressure welding of silicate and metallic Fe,Ni grains. We suggest that the same processes that converted impact debris into meteorite breccias also consolidated asteroidal rubble. Internal voids would be partly filled with regolith by impact-induced seismic shaking. Consolidation of this material beneath large craters would lithify asteroidal rubble to form a more coherent body. Fractures on Ida that were created by antipodal impacts and are concentrated in and near large craters, and small positive gravity anomalies associated with the Psyche and Himeros craters on Eros, are consistent with this concept. Spin data suggest that smaller asteroids 0.6-6 km in size are unconsolidated rubble piles. C-type asteroids, which are more porous than S-types, and their analogs, the volatile-rich carbonaceous chondrites, were probably not lithified by shock.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.8751H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.8751H"><span>Smooth pond-like deposits on asteroid 4 Vesta: First results from the Dawn mission.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hiesinger, H.; Ruesch, O.; Jaumann, R.; Nathues, A.; Raymond, C. A.; Russell, C. T.</p> <p>2012-04-01</p> <p>The Dawn spacecraft arrived at Vesta on July 16, 2011 to study the asteroid with a Framing Camera (FC), a Visible & Infrared Spectrometer (VIR), and a Gamma Ray and Neutron Detector (GRaND) [1]. Dawn provides the first high-resolution data from its survey orbit, high-altitude mapping orbit (HAMO), and low-altitude mapping orbit (LAMO). FC data revealed smooth pond-like deposits of ambiguous origin, similar to deposits on other asteroids, including Eros and Itokawa [2,3]. Several scenarios for the origin of these deposits can be tested with Dawn data, including volcanism, impact sedimentation, impact melt deposition, dust levitation and transport, seismic shaking, or landslides. We measured 83 small (~7 km2 average size) smooth deposits distributed across the surface of Vesta. Most ponds on Vesta occur on the floors of impact craters and in irregular depressions. We did not observe inflow of material into the depressions. Most of these deposits have well-defined geological contacts, indicating that they are younger than the surrounding terrain. However, lunar impact melt pools that formed contemporaneously with surrounding ejecta blankets show similar stratigraphic relationships. Sometimes the albedo of these ponds is lower than the surrounding terrain, in other cases the ponds are indistinguishable from the adjacent terrain. The ponds preferentially occur in a band between -10 and 30 degrees latitude with fewer ponds north of ~30 degrees and even fewer ponds in the southern hemisphere, i.e., the Rheasilvia region. The largest cluster of ponds occurs in the vicinity of the Marcia impact crater, which is part of the so-called snowman craters. Similar, but smaller (<230 m diameter) smooth ponds were also reported from the surface of asteroid Eros [2]. Robinson et al. [2] found that most smooth ponds on Eros occur in equatorial regions and concluded that the most likely process for their formation is electrostatic levitation and redistribution of the finest regolith components (<100 µm). Sierks et al. [4] argued that along the terminator, particularly strong electric fields can develop between the sun-lit and shaded areas, e.g., within craters, resulting in particle motion from sun-lit to dark regions. Dust levitation and transport was also discussed for asteroid 25143 Itokawa [3]. [1] Russell et al., (2007), Earth Moon Planets, 101; [2] Robinson et al., (2002), Met. Planet. Sci., 37; [3] Yano et al., (2006), Science, 312; [4] Sierks et al., (2011), Space Sci. Rev., doi:10.1007/s11214-011-9745-4. This research has been supported by the German Space Agency (DLR) and NASA. We would like to thank the Dawn Operations Team for their success-ful planning and acquisition of high-quality Vesta data.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MPBu...43..154S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MPBu...43..154S"><span>Results of the 2015 Mexican Asteroid Photometry Campaign</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sada, Pedro V.; Navarro-Meza, Samuel; Reyes-Ruiz, Mauricio; Olguin, Lorenzo L.; Saucedo, Julio C.; Loera-Gonzalez, Pablo</p> <p>2016-04-01</p> <p>The 2015 Mexican Asteroid Photometry Campaign was organized at the 2nd National Planetary Astrophysics Workshop held in 2015 March at the Universidad Autónoma de Nuevo León in Monterrey, México. Three asteroids were selected for coordinated observations from several Mexican observatories. We report full lightcurves for the main-belt asteroid 1084 Tamariwa (P = 6.195 ± 0.001 h) and near-Earth asteroid (NEA) 4055 Magellan (P = 7.479 ± 0.001 h). Asteroid 1466 Mundleria was also observed on eight nights but no lightcurve was obtained because of its faintness, a crowded field-of-view, and low amplitude (<0.03 mag).</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4841103C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4841103C"><span>The Large Super-Fast Rotators and Asteroidal Spin-Rate Distributions With Large Sky-Field Surveys Using iPTF</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chang, Chan-Kao; Lin, Hsing-Wen; Ip, Wing-Huen; iPTF Team</p> <p>2016-10-01</p> <p>In order to look for kilometer-sized super-fast rotators (large SFRs) and understand the spin-rate distributions of small (i.e. D of several kilometers) asteroids, we have been conducting asteroid rotation period surveys of large sky area using intermediate Palomar Transient Factory (iPTF) since 2014. So far, we have observed 261 deg2 with 20 min cadence, 188 deg2 with 10 min cadence, and 65 deg2 with 5 min cadence. From these surveys, we found that the spin-rate distributions of small asteroids at different locations in the main-belt are very similar. Moreover, the distributions of asteroids with 3 < D < 15 km show number decrease along with increase of spin rate for frequency > 5 rev/day, and that of asteroids with D < 3 km have a significant number drop at frequency = 5 rev/day. However, we only discover two new large SFRs and 24 candidates. Comparing with the ordinary asteroids, the population of large SFR seems to be far less than the whole asteroid population. This might indicate a peculiar group of asteroid for large SFRs.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AdSpR..59.1724D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AdSpR..59.1724D"><span>Optimised low-thrust mission to the Atira asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Di Carlo, Marilena; Romero Martin, Juan Manuel; Ortiz Gomez, Natalia; Vasile, Massimiliano</p> <p>2017-04-01</p> <p>Atira asteroids are recently-discovered celestial bodies characterised by orbits lying completely inside the heliocentric orbit of the Earth. The study of these objects is difficult due to the limitations of ground-based observations: objects can only be detected when the Sun is not in the field of view of the telescope. However, many asteroids are expected to exist in the inner region of the Solar System, many of which could pose a significant threat to our planet. In this paper, a small, low-cost, mission to visit the known Atira asteroids and to discover new Near Earth Asteroids (NEA) is proposed. The mission is realised using electric propulsion. The trajectory is optimised to maximise the number of visited asteroids of the Atira group using the minimum propellant consumption. During the tour of the Atira asteroids an opportunistic NEA discovery campaign is proposed to increase our knowledge of the asteroid population. The mission ends with a transfer to an orbit with perihelion equal to Venus's orbit radius. This orbit represents a vantage point to monitor and detect asteroids in the inner part of the Solar System and provide early warning in the case of a potential impact.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017Ap%26SS.362..229W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017Ap%26SS.362..229W"><span>Capture orbits around asteroids by hitting zero-velocity curves</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Wei; Yang, Hongwei; Zhang, Wei; Ma, Guangfu</p> <p>2017-12-01</p> <p>The problem of capturing a spacecraft from a heliocentric orbit into a high parking orbit around binary asteroids is investigated in the current study. To reduce the braking Δ V, a new capture strategy takes advantage of the three-body gravity of the binary asteroid to lower the inertial energy before applying the Δ V. The framework of the circular restricted three-body problem (CR3BP) is employed for the binary asteroid system. The proposed capture strategy is based on the mechanism by which inertial energy can be decreased sharply near zero-velocity curves (ZVCs). The strategy has two steps, namely, hitting the target ZVC and raising the periapsis by a small Δ V at the apoapsis. By hitting the target ZVC, the positive inertial energy decreases and becomes negative. Using a small Δ V, the spacecraft inserts into a bounded orbit around the asteroid. In addition, a rotating mass dipole model is employed for elongated asteroids, which leads to dynamics similar to that of the CR3BP. With this approach, the proposed capture strategy can be applied to elongated asteroids. Numerical simulations validate that the proposed capture strategy is applicable for the binary asteroid 90 Antiope and the elongated asteroid 216 Kleopatra.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title32-vol4/pdf/CFR-2012-title32-vol4-sec644-447.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title32-vol4/pdf/CFR-2012-title32-vol4-sec644-447.pdf"><span>32 CFR 644.447 - Joint survey of premises.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-07-01</p> <p>... 32 National Defense 4 2012-07-01 2011-07-01 true Joint survey of premises. 644.447 Section 644.447... ESTATE HANDBOOK Disposal Disposal of Leaseholds and Leasehold Improvements § 644.447 Joint survey of... terminal survey to determine the extent of restoration required, if any, will be prepared. The lessor will...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title32-vol4/pdf/CFR-2013-title32-vol4-sec644-447.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title32-vol4/pdf/CFR-2013-title32-vol4-sec644-447.pdf"><span>32 CFR 644.447 - Joint survey of premises.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-07-01</p> <p>... 32 National Defense 4 2013-07-01 2013-07-01 false Joint survey of premises. 644.447 Section 644... survey of premises. (a) When required. As soon as practical after restoration is requested by the lessor... the lease, and a terminal survey to determine the extent of restoration required, if any, will be...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title32-vol4/pdf/CFR-2010-title32-vol4-sec644-447.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title32-vol4/pdf/CFR-2010-title32-vol4-sec644-447.pdf"><span>32 CFR 644.447 - Joint survey of premises.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-07-01</p> <p>... 32 National Defense 4 2010-07-01 2010-07-01 true Joint survey of premises. 644.447 Section 644.447... ESTATE HANDBOOK Disposal Disposal of Leaseholds and Leasehold Improvements § 644.447 Joint survey of... terminal survey to determine the extent of restoration required, if any, will be prepared. The lessor will...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title32-vol4/pdf/CFR-2011-title32-vol4-sec644-447.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title32-vol4/pdf/CFR-2011-title32-vol4-sec644-447.pdf"><span>32 CFR 644.447 - Joint survey of premises.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-07-01</p> <p>... 32 National Defense 4 2011-07-01 2011-07-01 false Joint survey of premises. 644.447 Section 644... survey of premises. (a) When required. As soon as practical after restoration is requested by the lessor... the lease, and a terminal survey to determine the extent of restoration required, if any, will be...</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://archive.defense.gov/home/features/2006/jcoc0406','SCIGOVWS'); return false;" href="http://archive.defense.gov/home/features/2006/jcoc0406"><span>DefenseLink Special: Joint Civilian Orientation Conference, JCOC 71, April</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.science.gov/aboutsearch.html">Science.gov Websites</a></p> <p></p> <p></p> <p>Websites Contact Us Joint Civilian Orientation Conference 71 <em>Multi</em>-Service Orientation Program for Civilian in the Middle East: how the U.S. Coast Guard is helping keep Iraq's offshore oil terminals <em>operating</em> -improvised explosive device training at Forward <em>Operating</em> Base Sword in Kuwait, April 26, 2006. Hendrickson</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AsUAI...6...22B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AsUAI...6...22B"><span>Asteroid (457175) 2008 GO98: a quasi-Hilda comet. (Italian Title: Asteroide (457175) 2008 GO98:una cometa "quasi-Hilda")</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bacci, P.</p> <p>2017-12-01</p> <p>Cometary activity in the asteroid (457175) 2008 GO98 was observed at San Marcello Observatory, highlighting an extended coma and a tail of 36 arcseconds. The asteroid should be classified as a quasi-Hilda comet.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930030896&hterms=asteroid+belt&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dasteroid%2Bbelt','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930030896&hterms=asteroid+belt&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dasteroid%2Bbelt"><span>Small Main-Belt Asteroid Lightcurve Survey</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Binzel, Richard P.; Xu, Shui; Bus, Schelte J.; Bowell, Edward</p> <p>1992-01-01</p> <p>The Small Main-Belt Asteroid Lightcurve Survey is the first to measure main-belt asteroid lightcurve properties for bodies with diameters smaller than 5 km. Attention is given to CCD lightcurves for 32 small main-belt asteroids. The objects of this sample have a mean rotational frequency which is faster than that of larger main-belt asteroids. All lightcurves were investigated for nonperiodic variations ascribable to free precession; no conclusive detection of this phenomenon has been made, however.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201306180013HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201306180013HQ.html"><span>Asteroid Initiative Industry and Partner Day</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2013-06-18</p> <p>NASA Associate Administrator Robert Lightfoot, talks during the Asteroid Initiative Industry and Partner Day at NASA Headquarters on Tuesday, June 18, 2013 in Washington. During the event NASA Deputy Administrator Lori Garver and other senior NASA officials discussed the progress being made on NASA's mission to capture, redirect, and explore an asteroid. NASA also announced an Asteroid Grand Challenge focused on finding all asteroid threats to human populations and knowing what to do about them. Photo Credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997DPS....29.0722V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997DPS....29.0722V"><span>Compositional Variegation of Large-Diameter Low-Albedo Asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vilas, F.; Jarvis, K. S.; Anz-Meador, T. D.; Thibault, C. A.; Sawyer, S. R.; Fitzsimmons, A.</p> <p>1997-07-01</p> <p>Asteroids showing signs of aqueous alteration and thermal metamorphism in visible/near IR spectroscopy and photometry (C, G, F, B, and P classes) ranging from 0.37 - 0.90mu m dominate the asteroid population at heliocentric distances of 2.6 - 3.5 AU. Age dating of meteorites indicates that the Solar System was subjected to a major heating event 4.5 Gyr ago. Recent meteoritic research has produced evidence of a carbonaceous chondrite subjected to two separate aqueous alteration events with a metamorphic heating inbetween (Krot et al., 1997, submitted). Models of the effects of heating by electromagnetic induction or decay of short-lived radionuclides combined with models of the early collisional history of the Solar System after Jupiter's formation indicate that asteroids observed today can be divided into two groups by diameter. Those asteroids having diameters greater than 100 km were mixed by multiple collisions but remain as gravitationally bound rubble piles. Asteroids with diameters less than 100 km should show more compositional diversity. Vilas and Sykes (1996, Icarus, v. 124, 483) have shown using ECAS photometry that this compositional difference exists. Those asteroids having diameters greater than 100 km should be individually homogeneous, with spectral differences showing the combined effects of a primordial compositional gradient in the asteroid belt with thermal metamorphism. We address the significance of spatially-resolved spectra of 42 asteroids to the collective origin of these asteroids.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018Icar..304...14T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018Icar..304...14T"><span>Reconstructing the size distribution of the primordial Main Belt</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsirvoulis, G.; Morbidelli, A.; Delbo, M.; Tsiganis, K.</p> <p>2018-04-01</p> <p>In this work we aim to constrain the slope of the size distribution of main-belt asteroids, at their primordial state. To do so we turn out attention to the part of the main asteroid belt between 2.82 and 2.96 AU, the so-called "pristine zone", which has a low number density of asteroids and few, well separated asteroid families. Exploiting these unique characteristics, and using a modified version of the hierarchical clustering method we are able to remove the majority of asteroid family members from the region. The remaining, background asteroids should be of primordial origin, as the strong 5/2 and 7/3 mean-motion resonances with Jupiter inhibit transfer of asteroids to and from the neighboring regions. The size-frequency distribution of asteroids in the size range 17 < D(km) < 70 has a slope q ≃ - 1 . Using Monte-Carlo methods, we are able to simulate, and compensate for the collisional and dynamical evolution of the asteroid population, and get an upper bound for its size distribution slope q = - 1.43 . In addition, applying the same 'family extraction' method to the neighboring regions, i.e. the middle and outer belts, and comparing the size distributions of the respective background populations, we find statistical evidence that no large asteroid families of primordial origin had formed in the middle or pristine zones.</p> </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"><span>22</span></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><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <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"><span>23</span></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> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/22122894-origin-asteroid-ju-sub','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22122894-origin-asteroid-ju-sub"><span>THE ORIGIN OF ASTEROID 162173 (1999 JU{sub 3})</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Campins, Humberto; De Leon, Julia; Morbidelli, Alessandro</p> <p></p> <p>Near-Earth asteroid (162173) 1999 JU{sub 3} (henceforth JU{sub 3}) is a potentially hazardous asteroid and the target of the Japanese Aerospace Exploration Agency's Hayabusa-2 sample return mission. JU{sub 3} is also a backup target for two other sample return missions: NASA's OSIRIS-REx and the European Space Agency's Marco Polo-R. We use dynamical information to identify an inner-belt, low-inclination origin through the {nu}{sub 6} resonance, more specifically, the region with 2.15 AU < a < 2.5 AU and i < 8 Degree-Sign . The geometric albedo of JU{sub 3} is 0.07 {+-} 0.01, and this inner-belt region contains four well-defined low-albedomore » asteroid families (Clarissa, Erigone, Polana, and Sulamitis), plus a recently identified background population of low-albedo asteroids outside these families. Only two of these five groups, the background and the Polana family, deliver JU{sub 3}-sized asteroids to the {nu}{sub 6} resonance, and the background delivers significantly more JU{sub 3}-sized asteroids. The available spectral evidence is also diagnostic; the visible and near-infrared spectra of JU{sub 3} indicate it is a C-type asteroid, which is compatible with members of the background, but not with the Polana family because it contains primarily B-type asteroids. Hence, this background population of low-albedo asteroids is the most likely source of JU{sub 3}.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170003934','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170003934"><span>Geotechnical Tests on Asteroid Simulant Orgueil</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Garcia, Alexander D'marco</p> <p>2017-01-01</p> <p>In the last 100 years, the global population has more than quadrupled to over seven billion people. At the same time, the demand for food and standard of living has been increasing which has amplified the global water use by nearly eight times from approximately 500 to 4000 cu km per yr from 1900 to 2010. With the increasing concern to sustain the growing population on Earth it is necessary to seek other approaches to ensure that our planet will have resources for generations to come. In recent years, the advancement of space travel and technology has allowed the idea of mining asteroids with resources closer to becoming a reality. During the duration of the internship at NASA Kennedy Space Center, several geotechnical tests were conducted on BP-1 lunar simulant and asteroid simulant Orgueil. The tests that were conducted on BP-1 was to practice utilizing the equipment that will be used on the asteroid simulant and the data from those tests will be omitted from report. Understanding the soil mechanics of asteroid simulant Orgueil will help provide basis for future technological advances and prepare scientists for the conditions they may encounter when mining asteroids becomes reality in the distant future. Distinct tests were conducted to determine grain size distribution, unconsolidated density, and maximum density. Once the basic properties are known, the asteroid simulant will be altered to different levels of compaction using a vibrator table to see how compaction affects the density. After different intervals of vibration compaction, a miniature vane shear test will be conducted. Laboratory vane shear testing is a reliable tool to investigate strength anisotropy in the vertical and horizontal directions of a very soft to stiff saturated fine-grained clayey soil. This test will provide us with a rapid determination of the shear strength on the undisturbed compacted regolith. The results of these tests will shed light on how much torque is necessary to drill through the surface of an asteroid. Most of the known asteroids are believed to be left over material during the formation of the solar system that never accreted to form planets. Asteroids can be found in several groups such as Trojan Asteroids, Near Earth Asteroids (NEAs) and the main asteroid belt. The Trojan Asteroids orbit the 4th and 5th Lagrange points of major planets in the Solar System while the NEA's have orbits that are close to and sometimes intersect with Earths orbit and the Main Asteroid Belt which is found between the orbit of Mars and Jupiter. Gravitational perturbations can alter the orbit of asteroids in the Main Asteroid Belt causing them to move closer to earth causing them to become in the NEA class.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820056479&hterms=asteroid+belt&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dasteroid%2Bbelt','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820056479&hterms=asteroid+belt&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dasteroid%2Bbelt"><span>Main-belt asteroid exploration - Mission options for the 1990s</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Yen, C.-W. L.</p> <p>1982-01-01</p> <p>Mission configurations, propulsion systems, and target bodies for possible NASA asteroid exploration projects are examined. Noting that an announced delay in the development of a solar electric propulsion system has led to a consideration of chemical rocket systems, asteroid missions are grouped in terms of five potential areas for investigation, each successively further from the sun. The Shuttle-launched IUS is suggested as the prime candidate for boosting probes into trajectories for asteroid rendezvous with a number of the 3000 known asteroids. Planetary swingbys are mentioned as the only suitable method for satisfying the large energy requirements of the asteroid missions. Performance analyses are presented of the IUS 2-stage/Star-48 and Centaur vehicles, and sample missions to Fortuna, Anahita, and Urania in 1990 and further missions to the middle, outer, and Trojans asteroids are outlined.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950054130&hterms=Six+Sigma&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DSix%2BSigma','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950054130&hterms=Six+Sigma&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DSix%2BSigma"><span>Targeting an asteroid: The DSPSE encounter with asteroid 1620 Geographos</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Yeomans, Donald K.</p> <p>1993-01-01</p> <p>Accurate targeting of the Deep Space Program Science Experiment (DSPSE) spacecraft to achieve a 100 km sunward flyby of asteroid 1620 Geographos will require that the ground-based ephemeris of Geographos be well known in advance of the encounter. Efforts are underway to ensure that precision optical and radar observations are available for the final asteroid orbit update that takes place several hours prior to the DSPSE flyby. Because the asteroid passes very close to the Earth six days prior to the DSPSE encounter, precision ground-based optical and radar observations should be available. These ground-based data could reduce the asteroid's position uncertainties (1-sigma) to about 10 km. This ground-based target ephemeris error estimate is far lower than for any previous comet or asteroid that has been under consideration as a mission target.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PASJ...66...54H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PASJ...66...54H"><span>Lightcurve survey of V-type asteroids in the inner asteroid belt</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hasegawa, Sunao; Miyasaka, Seidai; Mito, Hiroyuki; Sarugaku, Yuki; Ozawa, Tomohiko; Kuroda, Daisuke; Nishihara, Setsuko; Harada, Akari; Yoshida, Michitoshi; Yanagisawa, Kenshi; Shimizu, Yasuhiro; Nagayama, Shogo; Toda, Hiroyuki; Okita, Kichi; Kawai, Nobuyuki; Mori, Machiko; Sekiguchi, Tomohiko; Ishiguro, Masateru; Abe, Takumi; Abe, Masanao</p> <p>2014-06-01</p> <p>We observed the lightcurves of 13 V-type asteroids [(1933) Tinchen, (2011) Veteraniya, (2508) Alupka, (3657) Ermolova, (3900) Knezevic, (4005) Dyagilev, (4383) Suruga, (4434) Nikulin, (4796) Lewis, (6331) 1992 FZ1, (8645) 1998 TN, (10285) Renemichelsen, and (10320) Reiland]. Using these observations we determined the rotational rates of the asteroids, with the exception of Nikulin and Renemichelsen. The distribution of rotational rates of 59 V-type asteroids in the inner main belt, including 29 members of the Vesta family, which are regarded as being ejecta from the asteroid (4) Vesta, is inconsistent with the best-fit Maxwellian distribution. This inconsistency may be due to the effect of thermal radiation Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) torques, which implies that the collision event that formed V-type asteroids is sub-billion to several billion years in age.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/22654336-asteroid-sizing-radiogalaxy-occultation-ghz','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22654336-asteroid-sizing-radiogalaxy-occultation-ghz"><span>ASTEROID SIZING BY RADIOGALAXY OCCULTATION AT 5 GHZ</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Lehtinen, K.; Muinonen, K.; Poutanen, M.</p> <p></p> <p>Stellar occultations by asteroids observed at visual wavelengths have been an important tool for studying the size and shape of asteroids and for revising the orbital parameters of asteroids. At radio frequencies, a shadow of an asteroid on the Earth is dominated by diffraction effects. Here, we show, for the first time, that a single observation of an occultation of a compact radio source at a frequency of 5 GHz can be used to derive the effective size of the occulting object and to derive the distance between the observer and the center of the occultation path on the Earth.more » The derived diameter of the occulting object, asteroid (115) Thyra, is 75 ± 6 km. The observed occultation profile shows features that cannot be explained by diffraction of a single asteroid.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA19644.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA19644.html"><span>Radar Movie of Asteroid 2011 UW158</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2015-07-23</p> <p>Scientists using two giant, Earth-based radio telescopes bounced radar signals off passing asteroid 2011 UW158 to create images for this animation showing the rocky body's fast rotation. The passing asteroid made its closest approach to Earth on July 19, 2015 at 7:37 a.m. PST (4:37 a.m. EST) at a distance of about 1.5 million miles (2.4 million kilometers, or 6 times the distance from Earth to the moon). The close proximity during the pass made 2011 UW158 one of the best asteroid flybys of 2015 for imaging from Earth using radar. The radar images reveal that the shape of the asteroid is extremely irregular and quite elongated. Prominent parallel, linear features run along the length of the object that cause a large increase in brightness of the radar images as they rotate into view. Scientists note that the asteroid appears to be fairly unusual. Its fast rotation suggests the object has greater mechanical strength than other asteroids its size. A fast-rotating asteroid with lower mechanical strength would tend to split apart. To obtain the views, researchers paired the 230-foot- (70-meter-) wide Deep Space Network antenna at Goldstone, California, in concert with the National Radio Astronomy Observatory's 330-foot (100-meter) Green Bank Telescope. Using this technique, the Goldstone antenna beams a radar signal at an asteroid and Green Bank receives the reflections. The technique, referred to as a bi-static observation, dramatically improves the amount of detail that can be seen in radar images. The new views obtained with the technique show features as small as about 24 feet (7.5 meters) wide. The 171 individual images used in the movie were generated from data collected on July 18. They show the asteroid is approximately 2000 by 1000 feet (600 by 300 meters) across. The observations also confirm earlier estimates by astronomers that the asteroid rotates quickly, completing one spin in just over half an hour. The movie spans a period of about an hour and 45 minutes. The trajectory of asteroid 2011 UW158 is well understood. This flyby was the closest approach the asteroid will make to Earth for at least the next 93 years. Asteroid 2011 UW158 was discovered on October 25, 2011, by the PanSTARRS 1 telescope, located on the summit of Haleakala on Maui, Hawaii. Managed by the University of Hawaii, the PanSTARRS survey receives NASA funding. Radar is a powerful technique for studying an asteroid's size, shape, rotation state, surface features and surface roughness, and for improving the calculation of asteroid orbits. Radar measurements of asteroid distances and velocities often enable computation of asteroid orbits much further into the future than if radar observations weren't available. http://photojournal.jpl.nasa.gov/catalog/PIA19644</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19870013938','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19870013938"><span>The 1986 DA and 1986 EB: M-class asteroids in near-Earth orbits</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gradie, Jonathan; Tedesco, Edward</p> <p>1987-01-01</p> <p>The Earth-approaching asteroid population is composed of asteroids in orbits with short lifetimes compared with the age of the solar system. These objects which are comprised of Aten, Apollo, and Amor asteroids must be replenished from either cometary or mainbelt asteroid sources since lifetimes against collision with or ejection by a planet are on the order of 10 to 100 million years. The physical study of Earth-approaching asteroids is constrained by the generally long period between favorable apparitions and poorly known orbits. Broadband spectrophotometry on the Johnson UBVR system and the Eight-Color Asteroid Survey system were obtained at Kitt Peak National Observatory and on the Johnson JHK system and at 10 and 20 microns at the NASA Infrared Telescope Facility at Mauna Kea Observatory. These observations were used to determine the absolute visual magnitudes and to derive the visual geometric albedos and diameters on the IRAS system. The spectral reflectance properties and geometric albedos of the M-class asteroids are consistent compositions analogous to the iron nickel meteorites or the enstatite-metal assemblages of the enstatite chondrites. The issue of the source(s) of the near-Earth asteroids population was examined by comparing the classifications on the scheme employed by Gradie and Tedesco of 38 such asteroids. Most of the near-Earth objects is indeed the asteroid belt as the observations suggest, then a method for removing extinct nuclei of short period comets must be found since the rate of production of short period comets from the long period comets is relatively large.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MPBu...45..244B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MPBu...45..244B"><span>Photometric Observations of Main-belt Asteroids 1968 Mehltretter 2681 Ostrovskij & 3431 Nakano</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brincat, Stephen M.; Galdies, Charles</p> <p>2018-07-01</p> <p>Lightcurves for three mid-belt asteroids were obtained from Flarestar Observatory (MPC171) and Znith Observatory in 2017 and 2018. These asteroids were selected from the Collaborative Asteroid Lightcurve Link (CALL) website. No reported observations were available to deduce their rotation periods prior to this research.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990041430&hterms=Physical+Research+Study&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DPhysical%2BResearch%2BStudy','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990041430&hterms=Physical+Research+Study&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DPhysical%2BResearch%2BStudy"><span>Studies of Asteroids and Comets</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bowell, Edward L. G.</p> <p>1998-01-01</p> <p>Research under this grant was carried out between 1989 and 1998. It comprised observational, theoretical, and computational research, mainly on asteroids. Two principal areas of research, centering on astrometry and photometry, were interrelated in their aim to study the overall structure of the asteroid belt and the orbital and physical properties of individual asteroids.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19780021073','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19780021073"><span>Asteroid collisions, craters, regoliths, and lifetimes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chapman, C. R.</p> <p>1978-01-01</p> <p>Laboratory experiments and computer modeling are used to predict the development of regoliths on all asteroids more than a few tens of kilometers in diameter, allowing for a wide range in the intrinsic strength of asteroidal surface materials. The high frequency of interasteroid collisions requires nearly all asteroids to be fragments of precursors.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170006940','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170006940"><span>Asteroid Pond Mineralogy: View from a Cognate Clast in LL3 NWA 8330</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zolensky, M.; Le, L.</p> <p>2017-01-01</p> <p>All asteroids surfaces imaged at the cm-scale reveal the presence of pond deposits. These ponds are important because it is likely all asteroid sample return missions will sample them, being the safest (very flat) places to touch down. Therefore, it is essential to understand the differences between the material at the pond surfaces and the host asteroid. Fortunately, some fine-grained cognate lithologies in chondrites show sedimentary features indicating that they sample asteroid ponds.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018Icar..304...24S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018Icar..304...24S"><span>Asteroids in three-body mean motion resonances with planets</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smirnov, Evgeny A.; Dovgalev, Ilya S.; Popova, Elena A.</p> <p>2018-04-01</p> <p>We have identified all asteroids in three-body mean-motion resonances in all possible planets configurations. The identification was done dynamically: the orbits of the asteroids were integrated for 100,000 yrs and the set of the resonant arguments was numerically analyzed. We have found that each possible planets configuration has a lot of the resonant asteroids. In total 65,972 resonant asteroids (≈14.1% of the total number of 467,303 objects from AstDyS database) have been identified.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930034911&hterms=lucy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dlucy','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930034911&hterms=lucy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dlucy"><span>CCD reflectance spectra of selected asteroids. I - Presentation and data analysis considerations</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vilas, Faith; Mcfadden, Lucy A.</p> <p>1992-01-01</p> <p>Narrowband reflectance spectra have been acquired which contribute to the library of asteroid data in the visible and near-IR spectral regions. The spectra support the existence of aqueous alteration products on asteroids located in the outer part of the main asteroid belt out to at least 4 AU. No evidence for features similar to the spectral features of ordinary chondrite meteorites was found in the spectra of asteroids located near the 3:1 Kirkwood Gap chaotic zone.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090013994','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090013994"><span>Diogenite-like Features in the Spitzer IRS (5-35 micrometers) Spectrum of 956 ELISA</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lim, Lucy F.; Emery, Joshua P.; Moskovitz, Nicholas A.</p> <p>2009-01-01</p> <p>We report preliminary results from the Spitzer Infrared Spectrograph (IRS) observations of the V-type asteroid 956 Elisa. Elisa was observed as part of a campaign to measure the 5.2-38 micron spectra of small basaltic asteroids with the Spitzer IRS. Targets include members of the dynamical family of the unique large differentiated asteroid 4 Vesta ("Vesroids"), several outer-main-belt basaltic asteroids whose orbits exclude them from originating on 4 Vesta, and the basaltic near-Earth asteroid 4055 Magellan.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201306180016HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201306180016HQ.html"><span>Asteroid Initiative Industry and Partner Day</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2013-06-18</p> <p>NASA Associate Administrator for Human Exploration and Operations, William Gerstenmaier, talks during the Asteroid Initiative Industry and Partner Day at NASA Headquarters on Tuesday, June 18, 2013 in Washington. During the event NASA Deputy Administrator Lori Garver and other senior NASA officials discussed the progress being made on NASA's mission to capture, redirect, and explore an asteroid. NASA also announced an Asteroid Grand Challenge focused on finding all asteroid threats to human populations and knowing what to do about them. Photo Credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201306180001HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201306180001HQ.html"><span>Asteroid Initiative Industry and Partner Day</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2013-06-18</p> <p>Jenn Gustetic, Prizes Program Executive, NASA Office of the Chief Technologist moderates the Asteroid Initiative Industry and Partner Day at NASA Headquarters on Tuesday, June 18, 2013 in Washington. During the event NASA Deputy Administrator Lori Garver and other senior NASA officials discussed the progress being made on NASA's mission to capture, redirect, and explore an asteroid. NASA also announced an Asteroid Grand Challenge focused on finding all asteroid threats to human populations and knowing what to do about them. Photo Credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201306180008HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201306180008HQ.html"><span>Asteroid Initiative Industry and Partner Day</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2013-06-18</p> <p>NASA Associate Administrator Science John Grunsfeld, Ph.D, talks during the Asteroid Initiative Industry and Partner Day at NASA Headquarters on Tuesday, June 18, 2013 in Washington. During the event NASA Deputy Administrator Lori Garver and other senior NASA officials discussed the progress being made on NASA's mission to capture, redirect, and explore an asteroid. NASA also announced an Asteroid Grand Challenge focused on finding all asteroid threats to human populations and knowing what to do about them. Photo Credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201306180009HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201306180009HQ.html"><span>Asteroid Initiative Industry and Partner Day</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2013-06-18</p> <p>NASA Associate Administrator for Space Technology, Mike Gazarik, Ph.D, talks during the Asteroid Initiative Industry and Partner Day at NASA Headquarters on Tuesday, June 18, 2013 in Washington. During the event NASA Deputy Administrator Lori Garver and other senior NASA officials discussed the progress being made on NASA's mission to capture, redirect, and explore an asteroid. NASA also announced an Asteroid Grand Challenge focused on finding all asteroid threats to human populations and knowing what to do about them. Photo Credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201306180011HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201306180011HQ.html"><span>Asteroid Initiative Industry and Partner Day</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2013-06-18</p> <p>NASA Associate Administrator Robert Lightfoot, listens as other NASA senior leadership talk during the Asteroid Initiative Industry and Partner Day at NASA Headquarters on Tuesday, June 18, 2013 in Washington. During the event NASA Deputy Administrator Lori Garver and other senior NASA officials discussed the progress being made on NASA's mission to capture, redirect, and explore an asteroid. NASA also announced an Asteroid Grand Challenge focused on finding all asteroid threats to human populations and knowing what to do about them. Photo Credit: (NASA/Bill Ingalls)</p> </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"><span>23</span></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><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <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"><span>24</span></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> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://images.nasa.gov/#/details-201306180024HQ.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-201306180024HQ.html"><span>Asteroid Initiative Industry and Partner Day</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2013-06-18</p> <p>Jason Kessler, Special Projects Program Executive, NASA Office of the Chief Technologist, talks during the Asteroid Initiative Industry and Partner Day at NASA Headquarters on Tuesday, June 18, 2013 in Washington. During the event NASA Deputy Administrator Lori Garver and other senior NASA officials discussed the progress being made on NASA's mission to capture, redirect, and explore an asteroid. NASA also announced an Asteroid Grand Challenge focused on finding all asteroid threats to human populations and knowing what to do about them. Photo Credit: (NASA/Bill Ingalls)</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19880043204&hterms=Trojan&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DTrojan','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19880043204&hterms=Trojan&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DTrojan"><span>Trojan and Hilda asteroid lightcurves. I - Anomalously elongated shapes among Trojans (and Hildas?)</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hartmann, William K.; Binzel, Richard P.; Tholen, David J.; Cruikshank, Dale P.; Goguen, Jay</p> <p>1988-01-01</p> <p>A comparison of the available sample of lightcurves for 26 Trojan and Hilda asteroids with belt asteroid lightcurves shows the former to be distinguished by a higher incidence of high amplitudes rgan belt asteroids of comparable size, suggesting more elongated shapes; they currently have, moreover, only a few percent of the main-belt asteroids' collision frequency. A more modest collisional evolution that may have affected the relative degree of fragmentation of these bodies, and thus their shapes, is inferred.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920003643','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920003643"><span>The 1990 MB: The first Mars Trojan</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bowell, Edward</p> <p>1991-01-01</p> <p>Asteroid 1990 MB was discovered during the course of the Mars and Earth-crossing Asteroid and Comet Survey. An orbit based on a 9-day arc and the asteroid's location near Mars L5 longitude led to speculation that it might be in 1:1 resonance with Mars, analogous to the Trojan asteroids of Jupiter. Subsequent observations strengthened the possibility, and later calculations confirmed it. The most recent orbit shows that the asteroid's semimajor axis is very similar to that of Mars.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014IAUS..310..180T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014IAUS..310..180T"><span>Dynamical properties of Watsonia asteroid family</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsirvoulis, Georgios; Novaković, Bojan; Knežević, Zoran; Cellino, Alberto</p> <p>2014-07-01</p> <p>In recent years, a rare class of asteroids has been discovered by Cellino et al. (2006), with its distinguishing characteristic being the anomalous polarimetric properties of its members. Named Barbarians, after (234) Barbara, the prototype of the class, these asteroids show negative polarization at unusually high phase-angles compared to normal asteroids. Motivated by the fact that some of the few discovered Barbarians seemed to be related to the Watsonia asteroid family, Cellino et al. (2014) performed a search for more Barbarians among its members. A positive result of this search led to the conclusion that Watsonia is indeed an important repository of Barbarian asteroids. Based on these findings, we decided to analyze this family in detail.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930063357&hterms=asteroid+belt&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dasteroid%2Bbelt','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930063357&hterms=asteroid+belt&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dasteroid%2Bbelt"><span>Evidence for a near-Earth asteroid belt</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rabinowitz, D. L.; Gehrels, T.; Scotti, J. V.; Mcmillan, R. S.; Perry, M. L.; Wisniewski, W.; Larson, S. M.; Howell, E. S.; Mueller, B. E. A.</p> <p>1993-01-01</p> <p>In January 1991, the 0.9-m Spacewatch telescope made the first observation of an asteroid outside Earth's atmosphere but in the neighborhood of the Earth-moon system. Since then, more than 40 Earth-approaching asteroids have been discovered, including 13 smaller than 50 m. Using these data, one of us has shown that there is an excess of Earth-approaching asteroids with diameters less than 50 m, relative to the population inferred from the distribution of larger objects. Here we argue that these smaller objects - characterized by low eccentricities, widely ranging inclinations and unusual spectral properties - form a previously undetected asteroid belt concentrated near Earth. The recent discovery of additional small Earth-approaching asteroids supports this conclusion.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900039964&hterms=asteroid+belt&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dasteroid%2Bbelt','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900039964&hterms=asteroid+belt&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dasteroid%2Bbelt"><span>Distribution of taxonomic classes and the compositional structure of the asteroid belt</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gradie, Jonathan C.; Chapman, Clark R.; Tedesco, Edward F.</p> <p>1989-01-01</p> <p>This paper reviews previous studies on the distribution of the asteroid taxonomic classes and analyzes the techniques, results, and interpretations of these studies, with special attention given to the strong and weak points of these studies and the important caveat for their interpretation. It is concluded that, in spite of the differences in class definition, the rather ordered heliocentric distribution of the composition is real and must be due to either primordial, evolutionary, or dynamical processes, or to a combination of all three. In general, the distribution of asteroid taxonomic classes is characterized by moderate-albedo asteroids dominant in the inner asteroid belt, and low-albedo asteroids prevalent in the outer belt and beyond.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/22364953-spectrum-jupiter-irregular-satellite-himalia','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22364953-spectrum-jupiter-irregular-satellite-himalia"><span></span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Brown, M. E.; Rhoden, A. R., E-mail: mbrown@caltech.edu, E-mail: Alyssa.Rhoden@jhuapl.edu</p> <p></p> <p>We present a medium resolution spectrum of Jupiter's irregular satellite Himalia covering the critical 3 μm spectral region. The spectrum shows no evidence for aqueously altered phyllosilicates, as had been suggested from the tentative detection of a 0.7 μm absorption, but instead shows a spectrum strikingly similar to the C/CF type asteroid 52 Europa. 52 Europa is the prototype of a class of asteroids generally situated in the outer asteroid belt between less distant asteroids which show evidence for aqueous alteration and more distant asteroids which show evidence for water ice. The spectral match between Himalia and this group of asteroids ismore » surprising and difficult to reconcile with models of the origin of the irregular satellites.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20060037608&hterms=earth+landing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dearth%2Blanding','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20060037608&hterms=earth+landing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dearth%2Blanding"><span>Orbital and Landing Operations at Near-Earth</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Scheeres, D. J.</p> <p>1995-01-01</p> <p>Orbital and landing operations about near-Earth asteroids are different than classical orbital operations about large bodies. The major differences lie with the small mass of the asteroid, the lower orbital velocities, the larger Solar tide and radiation pressure perturbations, the irregular shape of the asteroid and the potential for non-uniform rotation of the asteroid. These differences change the nature of orbits about an asteroid to where it is often common to find trajectories that evolve from stable, near-circular orbits to crashing or escaping orbits in a matter of days. The understanding and control of such orbits is important if a human or robotic presence at asteroids is to be commonplace in the future.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050175725','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050175725"><span>Mineralogy and Temperature-induced Spectral Investigations of A-type Asteroids 246 Asporina and 446 Aeternitas</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Reddy, V.; Hardersen, P. S.; Gaffey, M. J.; Abell, P. A.</p> <p>2005-01-01</p> <p>A-type asteroids are a relatively rare taxonomic class with no more than 17 known objects. They were first identified as a separate group of R-type asteroids based on broadband spectrophotometry by, and were later classified based on ECAS data by Tholen (1984). These asteroids have moderately high albedos (0.13-0.39), extremely reddish slopes shortward of 0.7 m and a strong absorption feature centered at approx. 1.05 m. More recent surveys like the Small Main-Belt Asteroid Spectroscopic Survey (SMASS) and SMASS II have expanded the taxonomic classes including the A-type, adding 12 new asteroids to the original five.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006DPS....38.5924K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006DPS....38.5924K"><span>Confusion Noise Due To Asteroids: From Mid-infrared To Millimetre Wavelengths</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kelemen, Janos; Kiss, C.; Pal, A.; Muller, T.; Abraham, P.</p> <p>2006-12-01</p> <p>We developed a statistical model for the asteroid component of the infrared sky for wavelengths 5 μm <= λ <= 1000 μm based on the Statistical Asteroid Model (Tedesco et al., 2005). Far-infrared fluxes of 1.9 million asteroids -derived with the help of the Standard Thermal Model -are used to calculate confusion noise values and expected asteroid counts for infrared space instruments in operation or in the near future (e.g. Akari, Herschel and Planck). Our results show that the confusion noise due to asteroids will not increase the detection threshold for most of the sky. However, there are specific areas near the ecliptic plane where the effect of asteroids can be comparable to the contribution of Galactic cirrus emission and that of the extragalactic background. This work was supported by the European Space Agency (PECS #98011) and by the Hungarian Space Office (TP286)</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003ESASP.481..157M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003ESASP.481..157M"><span>Asteroids as Calibration Standards in the Thermal Infrared -- Applications and Results from ISO</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Müller, T. G.; Lagerros, J. S. V.</p> <p></p> <p>Asteroids have been used extensively as calibration sources for ISO. We summarise the asteroid observational parameters in the thermal infrared and explain the important modelling aspects. Ten selected asteroids were extensively used for the absolute photometric calibration of ISOPHOT in the far-IR. Additionally, the point-like and bright asteroids turned out to be of great interest for many technical tests and calibration aspects. They have been used for testing the calibration for SWS and LWS, the validation of relative spectral response functions of different bands, for colour correction and filter leak tests. Currently, there is a strong emphasis on ISO cross-calibration, where the asteroids contribute in many fields. Well known asteroids have also been seen serendipitously in the CAM Parallel Mode and the PHT Serendipity Mode, allowing for validation and improvement of the photometric calibration of these special observing modes.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19242470','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19242470"><span>A record of planet migration in the main asteroid belt.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Minton, David A; Malhotra, Renu</p> <p>2009-02-26</p> <p>The main asteroid belt lies between the orbits of Mars and Jupiter, but the region is not uniformly filled with asteroids. There are gaps, known as the Kirkwood gaps, in distinct locations that are associated with orbital resonances with the giant planets; asteroids placed in these locations will follow chaotic orbits and be removed. Here we show that the observed distribution of main belt asteroids does not fill uniformly even those regions that are dynamically stable over the age of the Solar System. We find a pattern of excess depletion of asteroids, particularly just outward of the Kirkwood gaps associated with the 5:2, the 7:3 and the 2:1 Jovian resonances. These features are not accounted for by planetary perturbations in the current structure of the Solar System, but are consistent with dynamical ejection of asteroids by the sweeping of gravitational resonances during the migration of Jupiter and Saturn approximately 4 Gyr ago.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940021204','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940021204"><span>Asteroid exploration and utilization</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Radovich, Brian M.; Carlson, Alan E.; Date, Medha D.; Duarte, Manny G.; Erian, Neil F.; Gafka, George K.; Kappler, Peter H.; Patano, Scott J.; Perez, Martin; Ponce, Edgar</p> <p>1992-01-01</p> <p>The Earth is nearing depletion of its natural resources at a time when human beings are rapidly expanding the frontiers of space. The resources possessed by asteroids have enormous potential for aiding and enhancing human space exploration as well as life on Earth. Project STONER (Systematic Transfer of Near Earth Resources) is based on mining an asteroid and transporting raw materials back to Earth. The asteroid explorer/sample return mission is designed in the context of both scenarios and is the first phase of a long range plan for humans to utilize asteroid resources. Project STONER is divided into two parts: asteroid selection and explorer spacecraft design. The spacecraft design team is responsible for the selection and integration of the subsystems: GNC, communications, automation, propulsion, power, structures, thermal systems, scientific instruments, and mechanisms used on the surface to retrieve and store asteroid regolith. The sample return mission scenario consists of eight primary phases that are critical to the mission.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016IAUS..318..144J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016IAUS..318..144J"><span>Chang'e-2 spacecraft observations of asteroid 4179 Toutatis</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ji, Jianghui; Jiang, Yun; Zhao, Yuhui; Wang, Su; Yu, Liangliang</p> <p>2016-01-01</p> <p>On 13 December 2012, Chang'e-2 completed a successful flyby of the near-Earth asteroid 4179 Toutatis at a closest distance of 770 meters from the asteroid's surface. The observations show that Toutatis has an irregular surface and its shape resembles a ginger-root of a smaller lobe (head) and a larger lobe (body). Such bilobate shape is indicative of a contact binary origin for Toutatis. In addition, the high-resolution images better than 3 meters provide a number of new discoveries about this asteroid, such as an 800-meter depression at the end of the large lobe, a sharply perpendicular silhouette near the neck region, boulders, indicating that Toutatis is probably a rubble-pile asteroid. Chang'e-2 observations have significantly revealed new insights into the geological features and the formation and evolution of this asteroid. In final, we brief the future Chinese asteroid mission concept.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20030111255&hterms=goal+framing&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dgoal%2Bframing','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20030111255&hterms=goal+framing&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dgoal%2Bframing"><span>Dawn Mission: A Journey in Space and Time</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Russell, C. T.; Coradini, A.; DeSanctis, M. C.; Feldman, W. C.; Jaumann, R.; Konopliv, A. S.; McCord, T. B.; McFadden, L. A.; McSween, H. Y.; Mottola, S.</p> <p>2003-01-01</p> <p>By successively orbiting both 4 Vesta and 1 Ceres the Dawn mission directly addresses the longstanding goals of NASA and the planetary community to understand the origin and evolution of the solar system by obtaining geophysical and geochemical data on diverse main belt asteroids. Ceres and Vesta are two complementary terrestrial protoplanets (one apparently "wet" and one "dry"), whose accretion was terminated by the formation of Jupiter. Ceres is little changed since it formed in the early solar system, while Vesta has experienced significant heating and differentiation. Both have remained intact over the age of the solar system, thereby retaining a record of events and processes from the time of planet formation. Detailed study of the geophysics and geochemistry of these two bodies provides critical benchmarks for the early solar system conditions and processes that shaped its subsequent evolution. Dawn provides the missing context for both primitive and evolved meteoritic data, thus playing a central role in understanding terrestrial planet formation and the evolution of the asteroid belt. Dawn is to be launched in May 2006 arriving at Vesta in 2010 and Ceres in 2014, stopping at each to make 11 months of orbital measurements. The spacecraft uses solar electric propulsion both in cruise and in orbit to make most efficient use of its xenon propellant. The spacecraft carries a framing camera, visible and infrared mapping spectrometer, gamma ray/neutron spectrometer, a laser altimeter, magnetometer, and radio science.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994AVest..28...83S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994AVest..28...83S"><span>Asteroidal-meteoric complexes.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shestaka, I. S.</p> <p>1994-12-01</p> <p>Fourteen asteroidal-meteoric complexes were identified by means of the criterion of similarity of quasistationary parameters μ, ν and Tisserand's invariant Ti. Each of these complexes consists of several meteor swarms and one or several asteroids. The existence of such complexes confirms the possibility of formation of meteor swarms by means of disintegration of asteroids and their fragments.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JAnSc..65..183B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JAnSc..65..183B"><span>Asteroid Redirection Mission Evaluation Using Multiple Landers</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bazzocchi, Michael C. F.; Emami, M. Reza</p> <p>2018-06-01</p> <p>In this paper, a low-thrust tugboat redirection method is assessed using multiple spacecraft for a target range of small near-Earth asteroids. The benefits of a landed configuration of tugboat spacecraft in formation are examined for the redirection of a near-Earth asteroid. The tugboat method uses a gimballed thruster with a highly collimated ion beam to generate a thrust on the asteroid. The target asteroid range focuses on near-Earth asteroids smaller than 150 m in diameter, and carbonaceous (C-type) asteroids, due to the volatiles available for in-situ utilization. The assessment focuses primarily on the three key parameters, i.e., the asteroid mass redirected, the timeframe for redirection, and the overall system cost. An evaluation methodology for each parameter is discussed in detail, and the parameters are employed to determine the expected return and feasibility of the redirection mission. The number of spacecraft employed is optimized along with the electrical power needed for each spacecraft to ensure the highest possible return on investment. A discussion of the optimization results and the benefits of spacecraft formation for the tugboat method are presented.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Icar..269...15Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Icar..269...15Y"><span>Lightcurves of the Karin family asteroids</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yoshida, Fumi; Ito, Takashi; Dermawan, Budi; Nakamura, Tsuko; Takahashi, Shigeru; Ibrahimov, Mansur A.; Malhotra, Renu; Ip, Wing-Huen; Chen, Wen-Ping; Sawabe, Yu; Haji, Masashige; Saito, Ryoko; Hirai, Masanori</p> <p>2016-05-01</p> <p>The Karin family is a young asteroid family formed by an asteroid breakup 5.8 Myr ago. Since the members of this family probably have not experienced significant orbital or collisional evolution yet, it is possible that they still preserve properties of the original family-forming event in terms of their spin state. We carried out a series of photometric observations of the Karin family asteroids, and here we report on the analysis of the lightcurves including the rotation period of eleven members. The mean rotation rate of the Karin family members turned out to be much lower than those of near-Earth asteroids or small main belt asteroids (diameter D < 12 km), and even lower than that of large main belt asteroids (D > 130 km). We investigated a correlation between the peak-to-trough variation and the rotation period of the eleven Karin family asteroids, and found a possible trend that elongated members have lower spin rates, and less elongated members have higher spin rates. However, this trend has to be confirmed by another series of future observations.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870003016&hterms=speckle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dspeckle','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870003016&hterms=speckle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dspeckle"><span>Speckle interferometry applied to asteroids and other solar system objects</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Drummond, J. D.; Hege, E. K.</p> <p>1986-01-01</p> <p>Speckle interferometry is a high angular resolution technique that allows study of resolved asteroids. By following the changing size, shape, and orientation of minor planets, and with a few general assumptions (e.g., geometric scattering, triaxial ellipsoid figures, no albedo features), it is possible to directly measure an asteroid's true dimensions and the direction of its spin axis in one or two nights. A particular subset of triaxial ellipsoid figures are equilibrium shapes, and would imply that some asteroids are thoroughly fractured. Such shapes if they exist among the asteroids would allow a determination of bulk density since there is a unique relation among spin period, size, shape, and density. The discovery of even a single rubble pile, (just as the finding of even one binary asteroid by speckle interferometric techniques) would drastically alter the notion of asteroids as small solid planets. The Pluto/Charon system was studied to aid in improving the orbital elements necessary to predict the eclipse/occultation season currently in progress. Four asteroids were reduced to their size, shape, and pole direction: 433 Eros, 532 Herculina, 511 Davida, and 2 Pallas.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017eaa..book...85N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017eaa..book...85N"><span>Japanese Studies of Asteroids Following the Discovery of the Hirayama Families</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nakamura, Tsuko</p> <p></p> <p>This paper reviews studies relating to asteroids conducted by Japanese astronomers since the discovery of asteroid families by Kiyotsugu Hirayama in 1918. First, the situation is mentioned that it took quite some time for the concept of an `asteroid family' to be understood correctly by the astronomical community worldwide. It is no wonder that some eminent researches on the dynamics of asteroids based on secular perturbation theories appeared in Japan after WWII, as represented by the `Kozai mechanism' (1962), which probably was influenced by Hirayama's monumental discovery. As for studies of the physical nature of asteroids, we must note the pioneering work by M. Kitamura in 1959 when the observed colors of about 40 asteroids were compared with reflectance spectra of several meteorites measured in the laboratory, even though this result unfortunately was not pursued further at the time. Modern impact experiments initiated by A. Fujiwara in 1975 soon became an important means of investigating the origin of asteroid families, and of the ubiquitous craters seen on the surfaces of airless Solar System bodies.</p> </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"><span>24</span></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><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <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"><span>25</span></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> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018A%26A...611A..82B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018A%26A...611A..82B"><span>Size-dependent modification of asteroid family Yarkovsky V-shapes</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bolin, B. T.; Morbidelli, A.; Walsh, K. J.</p> <p>2018-04-01</p> <p>Context. The thermal properties of the surfaces of asteroids determine the magnitude of the drift rate cause by the Yarkovsky force. In the general case of Main Belt asteroids, the Yarkovsky force is indirectly proportional to the thermal inertia, Γ. Aim. Following the proposed relationship between Γ and asteroid diameter D, we find that asteroids' Yarkovsky drift rates might have a more complex size dependence than previous thought, leading to a curved family V-shape boundary in semi-major axis, a, vs. 1/D space. This implies that asteroids are drifting faster at larger sizes than previously considered decreasing on average the known ages of asteroid families. Methods: The V-Shape curvature is determined for >25 families located throughout the Main Belt to quantify the Yarkovsky size-dependent drift rate. Results: We find that there is no correlation between family age and V-shape curvature. In addition, the V-shape curvature decreases for asteroid families with larger heliocentric distances suggesting that the relationship between Γ and D is weaker in the outer MB possibly due to homogenous surface roughness among family members.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910016695','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910016695"><span>A census of the asteroid belt</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tedesco, E. F.; Veeder, G. J.</p> <p>1991-01-01</p> <p>Observations obtained by the Infrared Astronomical Satellite (IRAS) during its ten month mission in 1983 were originally processed by the Asteroid Data Analysis System (ADAS) to search for 3453 asteroids with known orbital elements as of September 1985. A total of 1811 had one or more observations of sufficient reliability to be accepted. These results were released in October 1986. Recently IRAS data were reprocessed to increase both the number of recognized asteroid observations and their reliability. As input 7311 asteroids were used with known orbital elements as of December 1990. This processor is referred to as the IRAS Minor Planet Survey (IMPS). As of April 1991 approximately 3000 asteroids had been identified with one or more acceptable observations. These results were used to derive the total number of asteroids with diameters greater than 1 km. In addition to being an interesting piece of information in itself these size-frequency distributions produce bias-correction factors which, for example, will be used in investigations of the physical properties of asteroid dynamical families and to estimate the distribution of the taxonomic classes as a function of heliocentric distance.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/22342147-near-infrared-spectra-high-albedo-outer-main-belt-asteroids','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22342147-near-infrared-spectra-high-albedo-outer-main-belt-asteroids"><span></span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Kasuga, Toshihiro; Shirahata, Mai; Usui, Fumihiko</p> <p></p> <p>Most outer main-belt asteroids have low albedos because of their carbonaceouslike bodies. However, infrared satellite surveys have revealed that some asteroids have high albedos, which may suggest the presence of unusual surface minerals for those primitive objects. We present new near-infrared (1.1–2.5 μm) spectra of four outer main-belt asteroids with albedos ≥ 0.1. The C-complex asteroids (555) Norma and (2542) Calpurnia are featureless and have (50%–60%) amorphous Mg pyroxenes that might explain the high albedos. Asteroids (701) Oriola (which is a C-complex asteroid) and (2670) Chuvashia (a D/T-type or M-type asteroid) show possible broad absorption bands (1.5–2.1 μm). The featuremore » can be reproduced by either Mg-rich amorphous pyroxene (with 50%–60% and 80%–95% Mg, respectively) or orthopyroxene (crystalline silicate), which might be responsible for the high albedos. No absorption features of water ice (near 1.5 and 2.0 μm) are detected in the objects. We discuss the origin of high albedo components in the outer main-belt asteroids and their physical relations to comets.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990116393&hterms=AVC&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DAVC','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990116393&hterms=AVC&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DAVC"><span>Asteroids and Comets Outreach Compilation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1999-01-01</p> <p>Contents include various different animations in the area of Asteroids and Comets. Titles of the short animated clips are: STARDUST Mission; Asteroid Castallia Impact Simulation; Castallia, Toutatis and the Earth; Simulation Asteroid Encounter with Earth; Nanorover Technology Task; Near Earth Asteroid Tracking; Champollian Anchor Tests; Early Views of Comets; Exploration of Small Bodies; Ulysses Resource Material from ESA; Ulysses Cometary Plasma Tail Animation; and various discussions on the Hale-Bopp Comet. Animation of the following are seen: the Stardust aerogel collector grid collecting cometary dust particles, comet and interstellar dust analyzer, Wiper-shield and dust flux monitor, a navigation camera, and the return of the sample to Earth; a comparison of the rotation of the Earth to the Castallia and Tautatis Asteroids; an animated land on Tautatis and the view of the motion of the sky from its surface; an Asteroid collision with the Earth; the USAF Station in Hawaii; close-up views of asteroids; automatic drilling of the Moon; exploding Cosmic Particles; and the dropping off of the plasma tail of a comet as it travels near the sun.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JAnSc.tmp....3B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JAnSc.tmp....3B"><span>Asteroid Redirection Mission Evaluation Using Multiple Landers</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bazzocchi, Michael C. F.; Emami, M. Reza</p> <p>2018-01-01</p> <p>In this paper, a low-thrust tugboat redirection method is assessed using multiple spacecraft for a target range of small near-Earth asteroids. The benefits of a landed configuration of tugboat spacecraft in formation are examined for the redirection of a near-Earth asteroid. The tugboat method uses a gimballed thruster with a highly collimated ion beam to generate a thrust on the asteroid. The target asteroid range focuses on near-Earth asteroids smaller than 150 m in diameter, and carbonaceous (C-type) asteroids, due to the volatiles available for in-situ utilization. The assessment focuses primarily on the three key parameters, i.e., the asteroid mass redirected, the timeframe for redirection, and the overall system cost. An evaluation methodology for each parameter is discussed in detail, and the parameters are employed to determine the expected return and feasibility of the redirection mission. The number of spacecraft employed is optimized along with the electrical power needed for each spacecraft to ensure the highest possible return on investment. A discussion of the optimization results and the benefits of spacecraft formation for the tugboat method are presented.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19790024062&hterms=round+earth&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dround%2Bearth','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19790024062&hterms=round+earth&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dround%2Bearth"><span>Round-trip missions to low delta-V asteroids and implications for material retrieval</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bender, D. F.; Dunbar, R. S.; Ross, D. J.</p> <p>1979-01-01</p> <p>Low-delta-V asteroids are to be found among those which have perihelia near 1 AU. From the 50 known asteroids with perihelia less than 1.5 AU, 10 candidates for asteroid retrieval missions were selected on the basis of low eccentricity and inclination. To estimate the ranges of orbital elements for which capture in earth orbit may be feasible, a survey was made of 180 deg transfer from a set of orbits having elements near those of the earth to the earth. For 2 of the 10 low-delta-V asteroids and for an additional one with elements more earth-like than any yet known, direct ballistic round trips in the 1980's were computed. A stay time of several months at the asteroid was used. The results show that the total delta V, including that for rendezvous with earth upon return, for the known asteroids is above 14 km/sec. But if asteroids are found similar to the strawman considered, the total delta V could be as low as 10 km/sec.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940005152','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940005152"><span>The IRAS Minor Planet Survey</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tedesco, Edward F.; Veeder, Glenn J.; Fowler, John W.; Chillemi, Joseph R.</p> <p>1992-01-01</p> <p>This report documents the program and data used to identify known asteroids observed by the Infrared Astronomical Satellite (IRAS) and to compute albedos and diameters from their IRAS fluxes. It also presents listings of the results obtained. These results supplant those in the IRAS Asteroid and Comet Survey, 1986. The present version used new and improved asteroid orbital elements for 4679 numbered asteroids and 2632 additional asteroids for which at least two-opposition elements were available as of mid-1991. It employed asteroid absolute magnitudes on the International Astronomical Union system adopted in 1991. In addition, the code was modified to increase the reliability of associating asteroids with IRAS sources and rectify several shortcomings in the final data products released in 1986. Association reliability was improved by decreasing the position difference between an IRAS source and a predicted asteroid position required for an association. The shortcomings addressed included the problem of flux overestimation for low SNR sources and the systematic difference in albedos and diameters among the three wavelength bands (12, 25, and 60 micrometers). Several minor bugs in the original code were also corrected.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000srrt.conf...19G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000srrt.conf...19G"><span>Mine Planning for Asteroid Orebodies</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gertsch, L. S.; Gertsch, R. E.</p> <p>2000-01-01</p> <p>Given that an asteroid (or comet) has been determined to contain sufficient material of value to be potentially economic to exploit, a mining method must be selected and implemented. This paper discusses the engineering necessary to bring a mine online, and the opportunities and challenges inherent in asteroid mineral prospects. The very important step of orebody characterization is discussed elsewhere. The mining methods discussed here are based on enclosing the asteroid within a bag in some fashion, whether completely or partially. In general, asteroid mining methods based on bags will consist of the following steps. Not all will be required in every case, nor necessarily in this particular sequence. Some steps will be performed simultaneously. Their purpose is to extract the valuable material from the body of the asteroid in the most efficient, cost-effective manner possible. In approximate order of initiation, if not of conclusion, the steps are: 1. Tether anchoring to the asteroid. 2. Asteroid motion control. 3. Body/fragment restraint system placement. 4. Operations platform construction. 5. Bag construction. 6. Auxiliary and support equipment placement. 7. Mining operations. 8. Processing operations. 9. Product transport to markets.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24695219','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24695219"><span>Thermal fatigue as the origin of regolith on small asteroids.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Delbo, Marco; Libourel, Guy; Wilkerson, Justin; Murdoch, Naomi; Michel, Patrick; Ramesh, K T; Ganino, Clément; Verati, Chrystele; Marchi, Simone</p> <p>2014-04-10</p> <p>Space missions and thermal infrared observations have shown that small asteroids (kilometre-sized or smaller) are covered by a layer of centimetre-sized or smaller particles, which constitute the regolith. Regolith generation has traditionally been attributed to the fall back of impact ejecta and by the break-up of boulders by micrometeoroid impact. Laboratory experiments and impact models, however, show that crater ejecta velocities are typically greater than several tens of centimetres per second, which corresponds to the gravitational escape velocity of kilometre-sized asteroids. Therefore, impact debris cannot be the main source of regolith on small asteroids. Here we report that thermal fatigue, a mechanism of rock weathering and fragmentation with no subsequent ejection, is the dominant process governing regolith generation on small asteroids. We find that thermal fragmentation induced by the diurnal temperature variations breaks up rocks larger than a few centimetres more quickly than do micrometeoroid impacts. Because thermal fragmentation is independent of asteroid size, this process can also contribute to regolith production on larger asteroids. Production of fresh regolith originating in thermal fatigue fragmentation may be an important process for the rejuvenation of the surfaces of near-Earth asteroids, and may explain the observed lack of low-perihelion, carbonaceous, near-Earth asteroids.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16957724','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16957724"><span>Developing space weathering on the asteroid 25143 Itokawa.</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hiroi, Takahiro; Abe, Masanao; Kitazato, Kohei; Abe, Shinsuke; Clark, Beth E; Sasaki, Sho; Ishiguro, Masateru; Barnouin-Jha, Olivier S</p> <p>2006-09-07</p> <p>Puzzlingly, the parent bodies of ordinary chondrites (the most abundant type of meteorites) do not seem to be abundant among asteroids. One possible explanation is that surfaces of the parent bodies become optically altered, to become the S-type asteroids which are abundant in the main asteroid belt. The process is called 'space weathering'-it makes the visible and near-infrared reflectance spectrum of a body darker and redder. A recent survey of small, near-Earth asteroids suggests that the surfaces of small S asteroids may have developing stages of space weathering. Here we report that a dark region on a small (550-metre) asteroid-25143 Itokawa-is significantly more space-weathered than a nearby bright region. Spectra of both regions are consistent with those of LL5-6 chondrites after continuum removal. A simple calculation suggests that the dark area has a shorter mean optical path length and about 0.04 per cent by volume more nanophase metallic iron particles than the bright area. This clearly shows that space-weathered materials accumulate on small asteroids, which are likely to be the parent bodies of LL chondrites. We conclude that, because LL meteorites are the least abundant of ordinary (H, L, and LL) chondrites, there must be many asteroids with ordinary-chondrite compositions in near-Earth orbits.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AJ....136..280V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AJ....136..280V"><span>Pairs of Asteroids Probably of a Common Origin</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vokrouhlický, David; Nesvorný, David</p> <p>2008-07-01</p> <p>We report the first observational evidence for pairs of main-belt asteroids with bodies in each pair having nearly identical orbits. The existence of ~60 pairs identified here cannot be reconciled with random fluctuations of the asteroid orbit density and rather suggests a common origin of the paired objects. We propose that the identified pairs formed by (i) collisional disruptions of km-sized and larger parent asteroids, (ii) Yarkovsky-O'Keefe-Radzievski-Paddack (YORP)-induced spin-up and rotational fission of fast-rotating objects, and/or (iii) splitting of unstable asteroid binaries. In case (i), the pairs would be parts of compact collisional families with many km- and sub-km-size members that should be found by future asteroid surveys. Our dynamical analysis suggests that most identified pairs formed within the past lsim1 Myr, in several cases even much more recently. For example, paired asteroids (6070) Rheinland and (54827) 2001 NQ8 probably separated from their common ancestor only 16.5-19 kyr ago. Given their putatively very recent formation, the identified objects are prime candidates for astronomical observations. The title paraphrases that of Hirayama's 1918 paper "Groups of asteroids probably of a common origin," where the first evidence was given for groups of asteroid fragments produced by disruptive collisions.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/22654505-unified-model-repeating-non-repeating-fast-radio-bursts','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22654505-unified-model-repeating-non-repeating-fast-radio-bursts"><span>A Unified Model for Repeating and Non-repeating Fast Radio Bursts</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Bagchi, Manjari, E-mail: manjari@imsc.res.in</p> <p></p> <p>The model that fast radio bursts (FRBs) are caused by plunges of asteroids onto neutron stars can explain both repeating and non-repeating bursts. If a neutron star passes through an asteroid belt around another star, there would be a series of bursts caused by a series of asteroid impacts. Moreover, the neutron star would cross the same belt repetitively if it were in a binary with the star hosting the asteroid belt, leading to a repeated series of bursts. I explore the properties of neutron star binaries that could lead to the only known repeating FRB so far (FRB121102). Inmore » this model, the next two epochs of bursts are expected around 2017 February 27 and 2017 December 18. On the other hand, if the asteroid belt is located around the neutron star itself, then a chance fall of an asteroid from that belt onto the neutron star would lead to a non-repeating burst. Even a neutron star grazing an asteroid belt can lead to a non-repeating burst caused by just one asteroid plunge during the grazing. This is possible even when the neutron star is in a binary with the asteroid-hosting star, if the belt and the neutron star orbit are non-coplanar.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EPSC....8.1043G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EPSC....8.1043G"><span>AIDA: The Asteroid Impact & Deflection Assessment Mission</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Galvez, A.; Carnelli, I.; Michel, P.; Cheng, A. F.; Reed, C.; Ulamec, S.; Biele, J.; Abell, P.; Landis, R.</p> <p>2013-09-01</p> <p>The Asteroid Impact and Deflection Assessment (AIDA) mission, a joint effort of ESA, JHU/APL, NASA, OCA, and DLR, is the first demonstration of asteroid deflection and assessment via kinetic impact. AIDA consists of two independent but mutually supporting mission elements, one of which is the asteroid kinetic impactor and the other is the characterization spacecraft. These two missions are, respectively, JHU/APL's Double Asteroid Redirection Test (DART) and the European Space Agency's Asteroid Investigation Mission (AIM) missions. As in the separate DART and AIM studies, the target of this mission is the binary asteroid [65803] Didymos in October, 2022. For a successful joint mission, one spacecraft, DART, would impact the secondary of the Didymos system while AIM would observe and measure any change in the relative orbit. AIM will be the first probe to characterise a binary asteroid, especially from the dynamical point of view, but also considering its interior and subsurface composition. The mission concept focuses on the monitoring aspects i.e., the capability to determine in-situ the key physical properties of a binary asteroid playing a role in the system's dynamic behavior. DART will be the first ever space mission to deflect the trajectory of an asteroid in a measurable way.- It is expected that the deflection can be measured as a change in the relative orbit period with a precision better than 10%. The joint AIDA mission will return vital data to determine the momentum transfer efficiency of the kinetic impact [1,2].</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013DPS....4520503D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013DPS....4520503D"><span>On the metal-rich surfaces of (16) Psyche and other M-type asteroids from interferometric observations in the thermal infrared</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Delbo, Marco; Matter, A.; Gundlach, B.; Blum, J.</p> <p>2013-10-01</p> <p>Asteroids belonging to the spectroscopic M-type exhibit a quasi featureless and moderately red reflectance spectrum and a geometric visible albedo between 0.1 and 0.3. These asteroids were initially thought to be metallic cores of differentiated asteroids that were exposed to space by a catastrophic disruption by impacts. Later, this view has been challenged by the detection of silicates and hydration spectroscopic bands on these bodies. Unveiling the physical properties of the surfaces of these asteroids, and identifying their meteorite analogs is a challenge from remote-sensing observations. Nevertheless, these are crucial problems, important for estimating the number of asteroids that underwent differentiation in the early phases of the formation of our solar system. The thermal inertia is a sensitive indicator for the presence of metal in the regolith on the surfaces of asteroids. We developed a new thermophysical model that allow us to derive the value of the thermal inertia from interferometric observations in the thermal infrared. We report on our investigation of the thermal inertia of M-type asteroids, including the asteroids (16) Psyche, for which we obtained a thermal inertia value anomalously high compared to the thermal inertia values of other asteroids in the same size range. From the thermal inertia and model of heat conductivity that accounts for different values of the packing fraction (a measure of the degree of compaction of the regolith particles) the regolith grain size is derived.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Icar..277...73C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Icar..277...73C"><span>Scale-dependent measurements of meteorite strength: Implications for asteroid fragmentation</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cotto-Figueroa, Desireé; Asphaug, Erik; Garvie, Laurence A. J.; Rai, Ashwin; Johnston, Joel; Borkowski, Luke; Datta, Siddhant; Chattopadhyay, Aditi; Morris, Melissa A.</p> <p>2016-10-01</p> <p>Measuring the strengths of asteroidal materials is important for developing mitigation strategies for potential Earth impactors and for understanding properties of in situ materials on asteroids during human and robotic exploration. Studies of asteroid disruption and fragmentation have typically used the strengths determined from terrestrial analog materials, although questions have been raised regarding the suitability of these materials. The few published measurements of meteorite strength are typically significantly greater than those estimated from the stratospheric breakup of meter-sized meteoroids. Given the paucity of relevant strength data, the scale-varying strength properties of meteoritic and asteroidal materials are poorly constrained. Based on our uniaxial failure studies of centimeter-sized cubes of a carbonaceous and ordinary chondrite, we develop the first Weibull failure distribution analysis of meteorites. This Weibull distribution projected to meter scales, overlaps the strengths determined from asteroidal airbursts and can be used to predict properties of to the 100 m scale. In addition, our analysis shows that meter-scale boulders on asteroids are significantly weaker than small pieces of meteorites, while large meteorites surviving on Earth are selected by attrition. Further, the common use of terrestrial analog materials to predict scale-dependent strength properties significantly overestimates the strength of meter-sized asteroidal materials and therefore is unlikely well suited for the modeling of asteroid disruption and fragmentation. Given the strength scale-dependence determined for carbonaceous and ordinary chondrite meteorites, our results suggest that boulders of similar composition on asteroids will have compressive strengths significantly less than typical terrestrial rocks.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('https://www.osti.gov/biblio/22520074-vestoids-part-ii-basaltic-nature-hed-meteorite-analogs-eight-sub-type-asteroids-associations-vesta','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22520074-vestoids-part-ii-basaltic-nature-hed-meteorite-analogs-eight-sub-type-asteroids-associations-vesta"><span>VESTOIDS, PART II: THE BASALTIC NATURE AND HED METEORITE ANALOGS FOR EIGHT V{sub p}-TYPE ASTEROIDS AND THEIR ASSOCIATIONS WITH (4) VESTA</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Hardersen, Paul S.; Reddy, Vishnu; Roberts, Rachel, E-mail: Hardersen@space.edu</p> <p></p> <p>Improving the constraints on the abundance of basaltic asteroids in the main asteroid belt is necessary for better understanding the thermal and collisional environment in the early solar system, for more rigorously identifying the genetic family for (4) Vesta, for determining the effectiveness of Yarkovsky/YORP in dispersing asteroid families, and for better quantifying the population of basaltic asteroids in the outer main belt (a > 2.5 AU) that is likely unrelated to (4) Vesta. Near-infrared (NIR) spectral observations in this work were obtained for the V{sub p}-type asteroids (2011) Veteraniya, (5875) Kuga, (8149) Ruff, (9147) Kourakuen, (9553) Colas, (15237) 1988 RL{sub 6},more » (31414) Rotaryusa, and (32940) 1995 UW{sub 4} during 2014 August/September utilizing the SpeX spectrograph at the NASA Infrared Telescope Facility, Mauna Kea, Hawaii. Spectral band parameter (band centers, band area ratios) and mineralogical analysis (pyroxene chemistry) for each average asteroid NIR reflectance spectrum suggest a howardite–eucrite–diogenite meteorite analog for each asteroid. (5875) Kuga is most closely associated with the eucrite meteorites, (31414) Rotaryusa is most closely associated with the diogenites, and the remaining other six asteroids are most closely associated with the howardite meteorites. Along with their orbital locations in the inner main belt and in the vicinity of (4) Vesta, the existing evidence suggests that these eight V{sub p}-type asteroids are also likely Vestoids.« less</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008DPS....40.5504P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008DPS....40.5504P"><span>Spin Rate Distribution of Small Asteroids Shaped by YORP Effect</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pravec, Petr</p> <p>2008-09-01</p> <p>We studied a distribution of spin rates of main belt/Mars crossing (MB/MC) asteroids with diameters 3-15 km using data obtained within the Photometric Survey of Asynchronous Binary Asteroids (Pravec et al. 2008). We found that the spin distribution of the small asteroids is uniform in the range from f = 1 to 9.5 d-1, and there is an excess of slow rotators with f < 1 d-1. The observed distribution appears to be controlled by the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect. The magnitude of the excess of slow rotators is related to the residence time of slowed down asteroids in the excess and the rate of spin rate change outside the excess. We estimated a median YORP spin rate change of 0.022 d-1/Myr for asteroids in our sample (i.e., a median time in which the spin rate changes by 1 d-1 is 45 Myr), thus the residence time of slowed down asteroids in the excess is 110 Myr. The spin rate distribution of near-Earth asteroids (NEAs) with sizes in the range 0.2-3 km ( 5-times smaller in median diameter than the MB/MC asteroids sample) shows a similar excess of slow rotators, but there is also a concentration of NEAs at fast spin rates with f = 9-10 d-1. The concentration at fast spin rates is correlated with a narrower distribution of spin rates of primaries of binary systems among NEAs; the difference may be due to the apparently more evolved population of binaries among MB/MC asteroids. Reference: Pravec, P., and 30 colleagues, 2008. Spin rate distribution of small asteroids. Icarus, in press. DOI: http://dx.doi.org/10.1016/j.icarus.2008.05.012</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MNRAS.468.1236B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MNRAS.468.1236B"><span>Scattering V-type asteroids during the giant planet instability: a step for Jupiter, a leap for basalt</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brasil, P. I. O.; Roig, F.; Nesvorný, D.; Carruba, V.</p> <p>2017-06-01</p> <p>V-type asteroids are a taxonomic class whose surface is associated with a basaltic composition. The only known source of V-type asteroids in the Main Asteroid Belt is (4) Vesta, which is located in the inner part of the Main Belt. However, many V-type asteroids cannot be dynamically linked to Vesta, in particular, those asteroids located in the middle and outer parts of the Main Belt. Previous works have failed to find mechanisms to transport V-type asteroids from the inner to the middle and outer belts. In this work, we propose a dynamical mechanism that could have acted on primordial asteroid families. We consider a model of the giant planet migration known as the jumping Jupiter model with five planets. Our study is focused on the period of 10 Myr that encompasses the instability phase of the giant planets. We show that, for different hypothetical Vesta-like paleo-families in the inner belt, the perturbations caused by the ice giant that is scattered into the asteroid belt before being ejected from the Solar system are able to scatter V-type asteroids to the middle and outer belts. Based on the orbital distribution of V-type candidates identified from the Sloan Digital Sky Survey and the VISTA Survey colours, we show that this mechanism is efficient enough provided that the hypothetical paleo-family originated from a 100 to 500 km crater excavated on the surface of (4) Vesta. This mechanism is able to explain the currently observed V-type asteroids in the middle and outer belts, with the exception of (1459) Magnya.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014MNRAS.438.2621W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014MNRAS.438.2621W"><span>Discovery and dynamical characterization of the Amor-class asteroid 2012 XH16</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wlodarczyk, I.; Cernis, K.; Boyle, R. P.; Laugalys, V.</p> <p>2014-03-01</p> <p>The near-Earth asteroid belt is continuously replenished with material originally moving in Amor-class orbits. Here, the orbit of the dynamically interesting Amor-class asteroid 2012 XH16 is analysed. This asteroid was discovered with the Vatican Advanced Technology Telescope (VATT) at the Mt Graham International Observatory as part of an ongoing asteroid survey focused on astrometry and photometry. The orbit of the asteroid was computed using 66 observations (57 obtained with VATT and 9 from the Lunar and Planetary Laboratory-Spacewatch II project) to give a = 1.63 au, e = 0.36, i = 3.76°. The absolute magnitude of the asteroid is 22.3 which translates into a diameter in the range 104-231 m, assuming the average albedos of S-type and C-type asteroids, respectively. We have used the current orbit to study the future dynamical evolution of the asteroid under the perturbations of the planets and the Moon, relativistic effects, and the Yarkovsky force. Asteroid 2012 XH16 is locked close to the strong 1:2 mean motion resonance with the Earth. The object shows stable evolution and could survive in near-resonance for a relatively long period of time despite experiencing frequent close encounters with Mars. Moreover, results of our computations show that the asteroid 2012 XH16 can survive in the Amor region at most for about 200-400 Myr. The evolution is highly chaotic with a characteristic Lyapunov time of 245 yr. Jupiter is the main perturber but the effects of Saturn, Mars and the Earth-Moon system are also important. In particular, secular resonances with Saturn are significant.</p> </li> <li> <p><a target="_blank" rel="noopener noreferrer" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016P%26SS..121...27C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016P%26SS..121...27C"><span>Asteroid Impact & Deflection Assessment mission: Kinetic impactor</span></a></p> <p><a target="_blank" rel="noopener noreferrer" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cheng, A. F.; Michel, P.; Jutzi, M.; Rivkin, A. S.; Stickle, A.; Barnouin, O.; Ernst, C.; Atchison, J.; Pravec, P.; Richardson, D. C.; AIDA Team</p> <p>2016-02-01</p> <p>The Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor to deflect an asteroid. AIDA is an international cooperation, consisting of two mission elements: the NASA Double Asteroid Redirection Test (DART) mission and the ESA Asteroid Impact Mission (AIM) rendezvous mission. The primary goals of AIDA are (i) to test our ability to perform a spacecraft impact on a potentially hazardous near-Earth asteroid and (ii) to measure and characterize the deflection caused by the impact. The AIDA target will be the binary near-Earth asteroid (65803) Didymos, with the deflection experiment to occur in late September, 2022. The DART impact on the secondary member of the binary at 7 km/s is expected to alter the binary orbit period by about 4 minutes, assuming a simple transfer of momentum to the target, and this period change will be measured by Earth-based observatories. The AIM spacecraft will characterize the asteroid target and monitor results of the impact in situ at Didymos. The DART mission is a full-scale kinetic impact to deflect a 150 m diameter asteroid, with known impactor conditions and with target physical properties characterized by the AIM mission. Predictions for the momentum transfer efficiency of kinetic impacts are given for several possible target types of different porosities, using Housen and Holsapple (2011) crater scaling model for impact ejecta mass and velocity distributions. Results are compared to numerical simulation results using the Smoothed Particle Hydrodynamics code of Jutzi and Michel (2014) with good agreement. The model also predicts that the ejecta from the DART impact may make Didymos into an active asteroid, forming an ejecta coma that may be observable from Earth-based telescopes. The measurements from AIDA of the momentum transfer from the DART impact, the crater size and morphology, and the evolution of an ejecta coma will substantially advance understanding of impact processes on asteroids.</p> </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"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <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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