Near-Earth asteroid satellite spins under spin-orbit coupling

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

Naidu, Shantanu P.; Margot, Jean-Luc

We develop a fourth-order numerical integrator to simulate the coupled spin and orbital motions of two rigid bodies having arbitrary mass distributions under the influence of their mutual gravitational potential. We simulate the dynamics of components in well-characterized binary and triple near-Earth asteroid systems and use surface of section plots to map the possible spin configurations of the satellites. For asynchronous satellites, the analysis reveals large regions of phase space where the spin state of the satellite is chaotic. For synchronous satellites, we show that libration amplitudes can reach detectable values even for moderately elongated shapes. The presence of chaoticmore » regions in the phase space has important consequences for the evolution of binary asteroids. It may substantially increase spin synchronization timescales, explain the observed fraction of asychronous binaries, delay BYORP-type evolution, and extend the lifetime of binaries. The variations in spin rate due to large librations also affect the analysis and interpretation of light curve and radar observations.« less

Analysis of impulsive maneuvers to keep orbits around the asteroid 2001SN263

NASA Astrophysics Data System (ADS)

Santos, Willer G.; Prado, Antonio F. B. A.; Oliveira, Geraldo M. C.; Santos, Leonardo B. T.

2018-01-01

The strongly perturbed environment of a small body, such as an asteroid, can complicate the prediction of orbits used for close proximity operations. Inaccurate predictions may make the spacecraft collide with the asteroid or escape to the deep space. The main forces acting in the dynamics come from the solar radiation pressure and from the body's weak gravity field. This paper investigates the feasibility of using bi-impulsive maneuvers to avoid the aforementioned non-desired phenomena (collisions and escapes) by connecting orbits around the triple system asteroid 2001SN263, which is the target of a proposed Brazilian space mission. In terms of a mathematical formulation, a recently presented rotating dipole model is considered with oblateness in both primaries. In addition, a "two-point boundary value problem" is solved to find a proper transfer trajectory. The results presented here give support to identifying the best strategy to find orbits for close proximity operations, in terms of long orbital lifetimes and low delta-V consumptions. Numerical results have also demonstrated the significant influence of the spacecraft orbital elements (semi-major axis and eccentricity), angular position of the Sun and spacecraft area-to-mass ratio, in the performance of the bi-impulsive maneuver.

Study of Some Dynamical Phenomena in the Solar System

NASA Astrophysics Data System (ADS)

Vaduvescu, O.

1997-08-01

The number of minor bodies in the Solar System is continuing to increase. More than 30,000 asteroids have been discovered by 1996, and about 7,000 have been catalogued. About 855 comets had known orbits by 1994. The number of known planetary satellites reached 60 (1996). All these minor bodies require improved astrometry, also more accurate physical parameters (sizes, masses, albedo, etc) to ensure accurate determination of their orbits. Some rapid dynamical phenomena could bring valuable information in this sense. Occultations and appulses (close approaches) of stars by asteroids represent the most accurate phenomena to determine or constraint sizes and shape of the asteroids. Given a fixed place, such events are very rare. Moreover, their prediction could be quite inaccurate, due to the reduced accuracy in both stellar and asteroid positions. Coordinated international campaigns, such as those lead by EAON (European Asteroidal Occultation Network) and IOTA (International Occultation Timing Association) could determine sizes and shapes of the asteroids. Some events could also lead to the discovery of double or triple asteroids systems. Four appulses involving PPM catalog stars and the minor planets (7) Iris, (297) Caecilia, (382) Dodona, and (824) Anastasia were observed by the author using the F=6m/D=0.38m refractor of the Astronomical Institute of the Romanian Academy (AIRA) in Bucharest. None were recorded as occultations, but their reduced astrometry (~0.01 arcsec) brought valuable information about the time of minimum approach and the minimum distance between the start and the asteroid, leading to some constraints about their sizes. Mutual phenomena in the systems of satellites of Jupiter and Saturn could bring valuable information about planetary and satellite masses, also about their moons orbits. Such phenomena are eclipses, occultations and passages between a satellite and the planet, and mutual eclipses and occultations between two satellites. Such events took place in 1995-1996 in the system of Saturn, when Earth passed through the plane of the ring of Saturn, allowing increased accuracy in timing and astrometry of the events, via photometry. Some contributions have been made by AIRA part of the international campaign PHESAT95 lead by Bureau des Longitudes in Paris, in which the author was involved part of a small team (3 people). Astrometry of a small CCD field (<5 arcmin) from a light polluted place (such as Bucharest) can be challenging, due to the few number of stars in the field, also to the low density of the astrometric catalogs (e.g., PPM). Most of the times only one or two stars in the field can be used for astrometry. The orientation of the CCD camera on the sky has to be determined for every observation, due to the flexure of the F=6m refractor which was determined to be different given various positions of the telescope during the night. A catalog of double, triple and multiple PPM stars in a small field (5x5 arcmin) was built in order to allow the observation of an orientation field close to every science field observed during the night. Some contributions to the astronomical software library of AIRA and its Astronomical Yearbook were made by the author in conjunction with this thesis. Other software were written to assist the observing runs and data reduction. We note here the following: CELESTIAL MAPS 5.0, MAPSAT, APRPPM, TOP, INTTOP, ORIENT, RELCCD, ABSCCD, PARGEO, SEPAD, EPHEMERID, LAPLACE, etc. Some contributions to the correlation of the orbital elements of the asteroids (semimajor axis, eccentricity, inclination, longitude of the ascending node and longitude of the perihelium) were made using the ASTEROIDS II database using the principal component analysis. A curious distribution of perihelion longitudes of the asteroids showing symmetry of the number of asteroids around perihelion longitude 180 deg was found using the IRAS database. This could be attributed to perturbations from Jupiter. Scanned thesis in pdf format available online at http://ovidiuvh.tripod.com/Teza-Romania/ (200 pags, 9 MB)

Utilization of multi-body trajectories in the Sun-Earth-Moon system

NASA Technical Reports Server (NTRS)

Farquhar, R. W.

1980-01-01

An overview of three uncommon trajectory concepts for space missions in the Sun-Earth-Moon System is presented. One concept uses a special class of libration-point orbits called 'halo orbits.' It is shown that members of this orbit family are advantageous for monitoring the solar wind input to the Earth's magnetosphere, and could also be used to establish a continuous communications link between the Earth and the far side of the Moon. The second concept employs pretzel-like trajectories to explore the Earth's geomagnetic tail. These trajectories are formed by using the Moon to carry out a prescribed sequence of gravity-assist maneuvers. Finally, there is the 'boomerang' trajectory technique for multiple-encounter missions to comets and asteroids. In this plan, Earth-swingby maneuvers are used to retarget the original spacecraft trajectory. The boomerang method could be used to produce a triple-encounter sequence which includes flybys of comets Halley and Tempel-2 as well as the asteroid Geographos.

Physical, spectral, and dynamical properties of asteroid (107) Camilla and its satellites

NASA Astrophysics Data System (ADS)

Pajuelo, M.; Carry, B.; Vachier, F.; Marsset, M.; Berthier, J.; Descamps, P.; Merline, W. J.; Tamblyn, P. M.; Grice, J.; Conrad, A.; Storrs, A.; Timerson, B.; Dunham, D.; Preston, S.; Vigan, A.; Yang, B.; Vernazza, P.; Fauvaud, S.; Bernasconi, L.; Romeuf, D.; Behrend, R.; Dumas, C.; Drummond, J. D.; Margot, J.-L.; Kervella, P.; Marchis, F.; Girard, J. H.

2018-07-01

The population of large 100+ km asteroids is thought to be primordial. As such, they are the most direct witnesses of the early history of our Solar System available. Those among them with satellites allow study of the mass, and hence density and internal structure. We study here the dynamical, physical, and spectral properties of the triple asteroid (107) Camilla from lightcurves, stellar occultations, optical spectroscopy, and high-contrast and high-angular-resolution images and spectro-images. Using 80 positions measured over 15 years, we determine the orbit of its larger satellite, S/2001 (107) 1, to be circular, equatorial, and prograde, with root-mean-square residuals of 7.8 mas, corresponding to a sub-pixel accuracy. From 11 positions spread over three epochs only, in 2015 and 2016, we determine a preliminary orbit for the second satellite S/2016 (107) 1. We find the orbit to be somewhat eccentric and slightly inclined to the primary's equatorial plane, reminiscent of the properties of inner satellites of other asteroid triple systems. Comparison of the near-infrared spectrum of the larger satellite reveals no significant difference with Camilla. Hence, both dynamical and surface properties argue for a formation of the satellites by excavation from impact and re-accumulation of ejecta in orbit. We determine the spin and 3-D shape of Camilla. The model fits well each data set: lightcurves, adaptive-optics images, and stellar occultations. We determine Camilla to be larger than reported from modeling of mid-infrared photometry, with a spherical-volume-equivalent diameter of 254 ± 36 km (3σuncertainty), in agreement with recent results from shape modeling (Hanus et al., 2017, A&A 601). Combining the mass of (1.12 ± 0.01) × 1019 kg (3σuncertainty) determined from the dynamics of the satellites and the volume from the 3-D shape model, we determine a density of 1,280 ± 130 kg · m-3 (3 σ uncertainty). From this density, and considering Camilla's spectral similarities with (24) Themis and (65) Cybele (for which water ice coating on surface grains was reported), we infer a silicate-to-ice mass ratio of 1-6, with a 10-30% macroporosity.

New observations and new models of spin-orbit coupling in binary asteroids

NASA Astrophysics Data System (ADS)

Margot, Jean-Luc; Naidu, Shantanu

2015-08-01

The YORP-induced rotational fission hypothesis is the leading candidate for explaining the formation of binaries, triples, and pairs among small (<20 km) asteroids (e.g., Margot et al, Asteroids IV, subm., 2015). Various evolutionary paths following rotational fission have been suggested, but many important questions remain about the evolutionary mechanisms and timescales. We test hypotheses about the evolution of binary asteroids by obtaining precise descriptions of the orbits and components of binary systems with radar and by examining the system dynamics with detailed numerical simulations. Predictions for component spin states and orbital precession rates can then be compared to observables in our data sets or in other data sets to elucidate the states of various systems and their likely evolutionary paths.Accurate simulations require knowledge of the masses, shapes, and spin states of individual binary components. Because radar observations can provide exquisite data sets spanning days with spatial resolutions at the decameter level, we can invert for the component shapes and measure spin states. We can also solve for the mutual orbit by fitting the observed separations between components. In addition, the superb (10e-7--10e-8) fractional uncertainties in range allow us to measure the reflex motions directly, allowing masses of individual components to be determined.We use recently published observations of the binary 2000 DP107 (Naidu et al. AJ, subm., 2015) and that of other systems to simulate the dynamics of components in well-characterized binary systems (Naidu and Margot, AJ 149, 80, 2015). We model the coupled spin and orbital motions of two rigid, ellipsoidal bodies under the influence of their mutual gravitational potential. We use surface of section plots to map the possible spin configurations of the satellites. For asynchronous satellites, the analysis reveals large regions of phase space where the spin state of the satellite is chaotic. The presence of chaotic regions may substantially increase spin synchronization timescales, delay BYORP-type evolution, extend the lifetime of binaries, and explain the observed fraction of asynchronous binaries.

Performance of High-Efficiency Advanced Triple-Junction Solar Panels for the LILT Mission Dawn

NASA Technical Reports Server (NTRS)

Fatemi, Navid S.; Sharma, Surya; Buitrago, Oscar; Sharps, Paul R.; Blok, Ron; Kroon, Martin; Jalink, Cees; Harris, Robin; Stella, Paul; Distefano, Sal

2005-01-01

NASA's Discovery Mission Dawn is designed to (LILT) conditions. operate within the solar system's Asteroid belt, where the large distance from the sun creates a low-intensity, low-temperature (LILT) condition. To meet the mission power requirements under LlLT conditions, very high-efficiency multi-junction solar cells were selected to power the spacecraft to be built by Orbital Sciences Corporation (OSC) under contract with JPL. Emcore's InGaP/InGaAs/Ge advanced triple-junction (ATJ) solar cells, exhibiting an average air mass zero (AMO) efficiency of greater than 27.6% (one-sun, 28 C), were used to populate the solar panels [1]. The two solar array wings, to be built by Dutch Space, with 5 large- area panels each (total area of 36.4 sq. meters) are projected to produce between 10.3 kWe and 1.3 kWe of end-of life (EOL) power in the 1.0 to 3.0 AU range, respectively. The details of the solar panel design, testing and power analysis are presented.

Petrologic evidence for collisional heating of chondritic asteroids

NASA Technical Reports Server (NTRS)

Rubin, Alan E.

1995-01-01

The identification of the mechanism(s) responsible for heating asteroids is among the major problems in planetary science. Because of difficulties with models of electromagnetic induction and the decay of short-lived radionuclides, it is worthwhile to evaluate the evidence for collisional heating. New evidence for localized impact heating comes from the high proportion of relict type-6 material among impact-melt-bearing ordinary chondrites (OC). This relict material was probably metamorphosed by residual heat within large craters. Olivine aggregates composed of faceted crystals with 120 deg triple junctions occur within the melted regions of the Chico and Rose City OC melt rocks; the olivine aggregates formed from shocked, mosaicized olivine grains that underwent contact metamorphism. Large-scale collisional heating is supoorted by the correlation in OC between petrologic type and shock stage; no other heating mechanism can readily account for this correlation. The occurrence of impact-melt-rock clasts in OC that have been metamorphosed along with their whole rocks indicates that some impact events preceded or accompanied thermal metamorphism. Such impacts events, occurring during or shortly after accretion, are probably responsible for substantially melting approximately 0.5% of OC. These events must have heated a larger percentage of OC to subsolidus temperatures sufficient to have caused significant metamorphism. If collisional heating is viable, then OC parent asteroids must have been large; large OC asteroids in the main belt may include those of the S(IV) spectral subtype. Collisional heating is inconsistent with layered ('onion-shell') structures in OC asteroids (wherein the degree of metamorphism increases with depth), but the evidence for such structures is weak. It seems likely that collisional heating played an important role in metamorphosing chondritic asteroids.

More Results from a Long-Term Radar Survey of M-Class Asteroids.

NASA Astrophysics Data System (ADS)

Shepard, Michael K.; Clark, B. E.; Benner, L. A.; Giorgini, J. D.; Magri, C.; Nolan, M. C.; Ostro, S. J.

2006-09-01

We present more results from our long-term radar survey of main-belt M-class asteroids. Because metals are denser and more radar reflective than silicates, an asteroid's radar cross-section can provide unambiguous information on its composition and near surface porosity [1]. The composition of this enigmatic class has important implications for the structure and evolution of the asteroid belt. As of July 2006 the following twelve main-belt M-class asteroids had been observed with radar: 16 Psyche [2,3,5], 21 Lutetia [3,5], 22 Kalliope [3], 83 Beatrix [4], 97 Klotho [3], 129 Antigone [5], 135 Hertha [5], 224 Oceana [5], 325 Heidelberga [5], and 785 Zwetana [5], 216 Kleopatra [4], and 796 Sarita [3]. Only one-third of this sample -- 16 Psyche, 129 Antigone, 216 Kleopatra and 785 Zwetana -- have radar albedos unambiguously consistent with metallic compositions [1,5]. Our goal is to triple the number of radar observed M-class targets within the next five years. We will present results focusing on the unusual radar variability of 129 Antigone. Acknowledgements. This work was partially supported by a grant from Bloomsburg University to MKS and NSF grant AST-0605903. The Arecibo Observatory is part of the National Astronomy and Ionosphere Center, which is operated by Cornell University under a cooperative agreement with the National Science Foundation. [1] Ostro et al. Science 252, 1399-1404, 1991. [2] Ostro et al. Science 229,442-446, 1985. [3] Magri et al. Icarus 140, 379-407, 1999. [4] Magri et al. submitted to Icarus. [5] Shepard et al in prep.

BILLIARDS: Baseline Instrumented Lithology Lander, Inspector and Asteroid Redirection Demonstration System

NASA Technical Reports Server (NTRS)

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

2015-01-01

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

Dynamics of rotationally fissioned asteroids: Source of observed small asteroid systems

NASA Astrophysics Data System (ADS)

Jacobson, Seth A.; Scheeres, Daniel J.

2011-07-01

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.

On The Attitude Dynamics Of Central Bodies Of Triples Systems 87 Sylvia, 45 Eugenia And 2001sn263.

NASA Astrophysics Data System (ADS)

Boldrin, Luiz Augusto; Winter, O. C.; Vieira Neto, E.

2012-10-01

The study of multiple asteroids is a great key for knowledge of our solar system past, since they are remaining objects of the formation of planets. Starting from that motivation, in a previous work on the system (87) Sylvia we studied the dynamics of Sylvia's satellites perturbed by the Sun and Jupiter. In that work it was shown that Romulus and Remus experience strong secular perturbations from the Sun and Jupiter, which could destabilize them. We also found out that the flatness (J2) of the central body is of extreme importance in the stability of the orbits of the satellites. From these results, we decided to do a study on the attitude motion of the main body of this kind of system and analyze its influence on the orbital motion of its satellites. The attitude motion of the central body of the triples systems 87 Sylvia, 45 Eugenia and 2001SN263 have been studied taking into account the torques from its satellites, the Sun and Jupiter. Analyzing the results through the temporal variation of the right ascension and declination of the central body's pole, we found that the satellites induce short period and low amplitude oscillations, and the Sun and Jupiter only provide large oscillations observed in long timescales. It was also observed a coupling between the orbital plane of the satellites and the equator plane of the central body, in such a way that the orbital plane always follows the equatorial plane of the central body, even with the latter experiencing great variations. Acknowledgements: CAPES, FAPESP and CNPq.

International Asteroid Mission (IAM)

NASA Astrophysics Data System (ADS)

Yamaguchi, Ryuuji

1991-07-01

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.

Asteroid volatiles inventory

NASA Technical Reports Server (NTRS)

Lebofsky, L. A.; Jones, T. D.; Herbert, F.

1989-01-01

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.

The 1986 DA and 1986 EB: M-class asteroids in near-Earth orbits

NASA Technical Reports Server (NTRS)

Gradie, Jonathan; Tedesco, Edward

1987-01-01

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.

Periodic Orbit Families in the Gravitational Field of Irregular-shaped Bodies

NASA Astrophysics Data System (ADS)

Jiang, Yu; Baoyin, Hexi

2016-11-01

The discovery of binary and triple asteroids in addition to the execution of space missions to minor celestial bodies in the past several years have focused increasing attention on periodic orbits around irregular-shaped celestial bodies. In the present work, we adopt a polyhedron shape model for providing an accurate representation of irregular-shaped bodies and employ the model to calculate their corresponding gravitational and effective potentials. We also investigate the characteristics of periodic orbit families and the continuation of periodic orbits. We prove a fact, which provides a conserved quantity that permits restricting the number of periodic orbits in a fixed energy curved surface about an irregular-shaped body. The collisions of Floquet multipliers are maintained during the continuation of periodic orbits around the comet 1P/Halley. Multiple bifurcations in the periodic orbit families about irregular-shaped bodies are also discussed. Three bifurcations in the periodic orbit family have been found around the asteroid 216 Kleopatra, which include two real saddle bifurcations and one period-doubling bifurcation.

Main-belt asteroid exploration - Mission options for the 1990s

NASA Technical Reports Server (NTRS)

Yen, C.-W. L.

1982-01-01

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.

The Fall and Recovery of the Tagish Lake Meteorite

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

Hildebrand, Alan R.; McCausland, Phil J.; Brown, Peter G.

2006-03-01

The Tagish Lake C2 (ungrouped) carbonaceous chondrite fall of January 18, 2000 delivered >10 kg of one of the most primitive and physically weak meteorites yet studied. In this paper we report the detailed circumstances of the fall and the recovery of all documented Tagish Lake fragments. We also provide measurements of bulk physical properties (mass, grain and bulk density), bulk triple oxygen-isotope ratios, and short-lived cosmogenic radionuclides counts for several fragments. Ground eyewitnesses and recorded observations of the Tagish Lake fireball event provide a refined estimate of the fireball trajectory, and hence, its pre-atmospheric orbit. From its calculated orbitmore » and its similarity to the remotely-sensed properties of the D and P-class asteroids, the Tagish Lake carbonaceous chondrite represents these outer belt asteroids, and is not of cometary origin. The bulk oxygen-isotope compositions reported here are among the highest known for meteorites. These data plot just below the Terrestrial Fractionation Line, following a trend similar to the CM meteorite mixing line. The bulk density of the Tagish Lake material (1.66 ±0.02 g/cm3) is the same, within error, as the total bulk densities of many C-class and especially D- and P-class asteroids. The high microporosity of Tagish Lake samples (~40%) provides an obvious candidate material for the composition of low bulk density primitive asteroids such as Phobos, Deimos and the P-class binary 87 Sylvia, without requiring a substantial contribution from macroporosity in the form of ice, thick regolith or “rubble pile” assemblages with large interior voids.« less

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

Reflectance spectrophotometry (about 0.5-1.0 micron) of oute-belt asteroids - Implications for primitive, organic solar system material

NASA Technical Reports Server (NTRS)

Vilas, F.; Smith, B. A.

1985-01-01

The surface compositions of outer-belt asteroids were used to obtain information about the origin of these asteroids. High-resolution CCD reflectance spectra of 21 asteroids, primarily P class, were examined for compositional information. Distinct slope changes are observed that suggest that these asteroids are the remnants of a compositional gradation of planetesimals in the outer solar system, which were retained selectively in location when other material was ejected from the solar system. Other data suggest that this gradation could extend through the orbits of Uranus and Neptune.

First results of the seven-color asteroid survey

NASA Astrophysics Data System (ADS)

Clark, Beth E.; Bell, Jeffrey F.; Fanale, Fraser P.; Lucey, Paul G.

1993-03-01

The new Seven-Color infrared filter system (SCAS), designed specifically to capture the essential mineralogical information present in asteroid spectra, is composed of seven broad-band filters which allow for IR observations of objects as faint as 17th magnitude. The first test of the SCAS system occurred in Jul. 1992. In four nights at the IRTF on Mauna Kea, Hawaii, over 67 objects were observed. Five of the observations were to test the new system for accuracy relative to previous observations with the high-resolution 52 Color Infrared Survey and with the Eight-Color Asteroid Survey (ECAS). In three cases, the match with previous data was good. In two cases, the match to previous observations was not as good. In addition, sixty S-Type asteroids were measured with the SCAS system. Forty of those asteroids were also observed with the ECAS system. Among the new observations is infrared data of 371 Bohemia, a main belt asteroid which was classified 'QSV' according to its UBV colors in the taxonomic system of D.J. Tholen. There are no corresponding ECAS data for 371. Q-type asteroids are of special interest as they are proposed to be the elusive parent bodies of the ordinary chondrite meteorites. Most Q-types are Earth-crossing asteroids and have not yet been observed in the infrared (except, perhaps, 371). Positive identification of a large main belt Q-type would be of major importance in the scheme of the geological structure of the asteroid belt. Without visible wavelength data, however, the classification of 371 Bohemia remains ambiguous. An attempt to conjoin Bohemia SCAS data with ECAS data of both a typical Q-Type asteroid and an average S-Type asteroid is shown. This figure thus illustrates the importance of visible wavelength data to the SCAS system. In other words, without ECAS data of 371 Bohemia we cannot use its spectral characteristics to identify it as a possible parent body of ordinary chondrite meteorites.

Application of a Novel Long-Reach Manipulator Concept to Asteroid Redirect Missions

NASA Technical Reports Server (NTRS)

Dorsey, John T.; Doggett, William R.; Jones, Thomas C.; King, Bruce D.

2015-01-01

A high priority mission currently being formulated by NASA is to capture all or part of an asteroid and return it to cis-lunar space for examination by an astronaut crew. Two major mission architectures are currently being considered: in the first (Mission Concept A), a spacecraft would rendezvous and capture an entire free flying asteroid (up to 14 meters in diameter), and in the second (Mission Concept B), a spacecraft would rendezvous with a large asteroid (which could include one of the Martian moons) and retrieve a boulder (up to 4 meters in diameter). A critical element of the mission is the system that will capture the asteroid or boulder material, enclose it and secure it for the return flight. This paper describes the design concepts, concept of operations, structural sizing and masses of capture systems that are based on a new and novel Tendon- Actuated Lightweight In-Space MANipulator (TALISMAN) general-purpose robotic system. Features of the TALISMAN system are described and the status of its technology development is summarized. TALISMAN-based asteroid material retrieval system concepts and concepts-of-operations are defined for each asteroid mission architecture. The TALISMAN-based capture systems are shown to dramatically increase operational versatility while reducing mission risk. Total masses of TALISMAN-based systems are presented, reinforcing the mission viability of using a manipulator-based approach for the asteroid redirect mission.

Stochastic YORP On Real Asteroid Shapes

NASA Astrophysics Data System (ADS)

McMahon, Jay W.

2015-05-01

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.

THE PUZZLING MUTUAL ORBIT OF THE BINARY TROJAN ASTEROID (624) HEKTOR

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

Marchis, F.; Cuk, M.; Durech, J.

Asteroids with satellites are natural laboratories to constrain the formation and evolution of our solar system. The binary Trojan asteroid (624) Hektor is the only known Trojan asteroid to possess a small satellite. Based on W. M. Keck adaptive optics observations, we found a unique and stable orbital solution, which is uncommon in comparison to the orbits of other large multiple asteroid systems studied so far. From lightcurve observations recorded since 1957, we showed that because the large Req = 125 km primary may be made of two joint lobes, the moon could be ejecta of the low-velocity encounter, which formedmore » the system. The inferred density of Hektor's system is comparable to the L5 Trojan doublet (617) Patroclus but due to their difference in physical properties and in reflectance spectra, both captured Trojan asteroids could have a different composition and origin.« less

Taxonomy of asteroids. [according to polarimetric, spectrophotometric, radiometric, and UBV photometric data

NASA Technical Reports Server (NTRS)

Bowell, E.; Chapman, C. R.; Gradie, J. C.; Zellner, B.; Morrison, D.

1978-01-01

A taxonomic system for asteroids is discussed which is based on seven directly observable parameters from polarimetry, spectrophotometry, radiometry, and UBV photometry. The classification scheme is entirely empirical and independent of specific mineralogical interpretations. Five broad classes (designated C, S, M, E, and R), as well as an 'unclassifiable' designation, are defined on the basis of observational data for 523 asteroids. Computer-generated type classifications and derived diameters are given for the 523 asteroids, and the application of the classification procedure is illustrated. Of the 523 asteroids classified, 190 are identified as C objects, 141 as S type, 13 as type M, three as type E, three as type R, 55 as unclassifiable, and 118 as ambiguous. The present taxonomic system is compared with several other asteroid classification systems.

ORBITS, MASSES, AND EVOLUTION OF MAIN BELT TRIPLE (87) SYLVIA

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

Fang, Julia; Margot, Jean-Luc; Rojo, Patricio

Sylvia is a triple asteroid system located in the main belt. We report new adaptive optics observations of this system that extend the baseline of existing astrometric observations to a decade. We present the first fully dynamical three-body model for this system by fitting to all available astrometric measurements. This model simultaneously fits for individual masses, orbits, and primary oblateness. We find that Sylvia is composed of a dominant central mass surrounded by two satellites orbiting at 706.5 {+-} 2.5 km and 1357 {+-} 4.0 km, i.e., about 5 and nearly 10 primary radii. We derive individual masses of 1.484{supmore » +0.016}{sub -0.014} Multiplication-Sign 10{sup 19} kg for the primary (corresponding to a density of 1.29 {+-} 0.39 g cm{sup -3}), 7.33{sup +4.7}{sub -2.3} Multiplication-Sign 10{sup 14} kg for the inner satellite, and 9.32{sup +20.7}{sub -8.3} Multiplication-Sign 10{sup 14} kg for the outer satellite. The oblateness of the primary induces substantial precession and the J{sub 2} value can be constrained to the range of 0.0985-0.1. The orbits of the satellites are relatively circular with eccentricities less than 0.04. The spin axis of the primary body and the orbital poles of both satellites are all aligned within about 2 deg of each other, indicating a nearly coplanar configuration and suggestive of satellite formation in or near the equatorial plane of the primary. We also investigate the past orbital evolution of the system by simulating the effects of a recent passage through 3:1 mean-motion eccentricity-type resonances. In some scenarios this allow us to place constraints on interior structure and past eccentricities.« less

Momentum harvesting techniques for solar system travel

NASA Technical Reports Server (NTRS)

Willoughby, Alan J.

1990-01-01

Astronomers are lately estimating there are 400,000 Earth visiting asteroids larger than 100 meters in diameter. These asteroids are accessible sources of building materials, propellants, oxygen, water, and minerals which also constitute a huge momentum reserve, potentially usable for travel throughout the solar system. To use this momentum, these stealthy objects must be tracked and the extraction of the momentum wanted must be learned. Momentum harvesting by momentum transfer from asteroid to spacecraft, and by using the momentum of the extraterrestrial material to help deliver itself to the destination are discussed. A net and tether concept is the suggested means of asteroid capture, the basic momentum exchange process. The energy damping characteristics of the tether will determine the velocity mismatch that can be tolerated, and hence the amount of momentum that can be harvested per capture. As it plays out of its reel, drag on the tether steadily accelerates the spacecraft. A variety of concepts for riding and using the asteroid after capture are discussed. The hitchhiker uses momentum transfer only. The beachcomber, the caveman, the swinger, the prospector, and the rock wrecker also take advantage of raw asteroidal materials. The chemist and the hijacker go further, they process the asteroid into propellant. Or, an 'asteroid railway system' could evolve with each hijacked asteroid becoming a scheduled train. Travelers could board the space railway system assured that water, oxygen, and propellants await them.

Radar investigations of near-Earth asteroids at Arecibo and Goldstone

NASA Astrophysics Data System (ADS)

Brozovic, M.; Nolan, M.; Benner, L.; Busch, M.; Howell, E.; Taylor, P.; Springmann, A.; Giorgini, J.; Margot, J.; Magri, C.; Sheppard, M.; Naidu, S.

2014-07-01

Radar observations are a powerful technique to study near-Earth asteroids (NEAs). The Arecibo and Goldstone planetary radars can provide delay-Doppler images that can directly resolve surface features such as concavities, hills, ridges, and boulders. Goldstone's 3.75-m resolution capability is invaluable when attempting to image NEAs with diameters smaller than 50 m. To date, over 430 near-Earth asteroids and 136 main-belt asteroids have been observed with radar. 80 % of the radar-detected NEAs have been observed within the last 10 years. The radar detection rate in the last three years has tripled relative to the average in the previous decade due to an increase in funding and greater scheduling flexibility. Currently, ˜400 observing hours per year at Goldstone and ˜600 observing hours per year at Arecibo are devoted to observing asteroids. We strive to observe all strong and moderately strong imaging targets, Yarkovsky drift candidates, NEOWISE targets, asteroids with very low perihelia that can be used to measure solar oblateness, and as many other detectable asteroids as resources allow. We also regularly attempt to observe any asteroid that is flagged by the Near-Earth Object Human Spaceflight Accessible Targets Study (NHATS) list (http://neo.jpl.nasa.gov/nhats/). To date, we have observed more than 60 NHATS objects at Arecibo and Goldstone. In the past three years, ˜1/3 of the detected asteroids were targets of opportunity (TOOs), some of which we observed within 24 h from when the discoveries were announced. Many TOOs are small, rapidly moving objects that are detectable by radar only within few lunar distances. Radar astrometry is particularly important for these asteroids because they are too faint to be followed for long with optical telescopes. A radar-range measurement often secures their orbit for decades or centuries, where otherwise the object would be lost and require rediscovery. In one of the extreme cases, two delay and two Doppler measurements from Goldstone prevented a newly discovered potentially hazardous asteroid (PHA) 2014 CU_{13} from being lost. The measurements also extended its Earth-encounter predictability by 1000 years. Radar observations of objects that are closer than ˜4 lunar distances (˜10.3 seconds RTT, round-trip-time for signal) previously required coordination between two stations (one for transmit and one for receive) due to the short RTT and need to physically switch between transmit and receive configurations. However, the switching process has been accelerated and recent observations of 2013 XY_8 have shown that Goldstone can now conduct monostatic observations with RTTs of ˜5 seconds. This provides much stronger signal-to-noise ratios for very close targets. With the rapidly growing number of radar detections, some population trends are emerging. The latest statistics show that the fraction of contact binaries has grown to ˜14 % and is now comparable to that of true binaries in the NEA population with diameters larger than 200 m. We are also starting to capture what may be the tail ends of certain sub-populations. For example, we have found two very small binary systems, 2003 SS_{84} and 2004 FG_{11}, that have primaries < 200 m in diameter; we have also found that 2005 AY_{28} and 2013 JR_{28} are contact binaries in the same size range. These objects are at the boundary between gravitationally bound ''rubble piles'' and strength-dominated, possibly monolithic objects. The NEAs are a very diverse population, in which we continue to discover unusual objects. It is difficult to anticipate what the future radar observations may uncover, but surprises are likely.

Special issue on asteroids - Introduction

NASA Astrophysics Data System (ADS)

Novaković, Bojan; Hsieh, Henry H.; Gronchi, Giovanni F.

2018-04-01

The articles in this special issue are devoted to asteroids, small solar system bodies that primarily populate a region between the orbits of Mars and Jupiter, known as the asteroid belt, but can also be found throughout the Solar System. Asteroids are considered to be a key to understanding the formation and evolution of our planetary system. Their properties allow us to test current theoretical models and develop new theoretical concepts pertaining to evolutionary processes in the Solar System. There have been major advances in asteroid science in the last decade, and that trend continues. Eighteen papers accepted for this special issue cover a wide range of asteroid-related subjects, pushing the boundaries of our understanding of these intriguing objects even further. Here we provide the reader with a brief overview of these thrilling papers, with an invitation for interested scientists to read each work in detail for a better understanding of these recent cutting edge results. As many topics in asteroid science remain open challenges, we hope that this special issue will be an important reference point for future research on this compelling topic.

Antimatter applied for Earth protection from asteroid collision

NASA Technical Reports Server (NTRS)

Satori, Shin; Kuninaka, Hitoshi; Kuriki, Kyoichi

1990-01-01

An Earth protection system against asteroids and meteorites in colliding orbit is proposed. The system consists of detection and deorbiting systems. Analyses are given for the resolution of microwave optics, the detectability of radar, the orbital plan of intercepting operation, and the antimatter mass require for totally or partially blasting the asteroid. Antimatter of 1 kg is required for deorbiting an asteroid 200 m in diameter. An experimental simulation of antimatter cooling and storage is planned. The facility under construction is discussed.

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.

OSIRIS-REx A NASA Mission to a Near Earth Asteroid!...and Other Recent Happenings in the Solar System

NASA Technical Reports Server (NTRS)

Moreau, Michael C.

2015-01-01

The OSIRIS-REx Mission launches in 2016 Arrives at Asteroid Bennu-2018 Returns a sample to Earth -2023 The mission, OSIRIS-REx, will visit an asteroid and return a sample from the early Solar System to help us understand how our Solar System formed.

Radar evidence for diverse shapes of the primaries among binary near-Earth asteroids

NASA Astrophysics Data System (ADS)

Brozovic, Marina; Benner, Lance; Ford, Thomas; Springmann, Alessondra; Taylor, Patrick; Shepard, Michael; Margot, Jean-Luc; Naidu, Shantanu; Nolan, Michael; Howell, Ellen; Busch, Michael; Giorgini, Jon; Magri, Christopher

2014-11-01

The Arecibo and Goldstone planetary radars have been exceptionally valuable instruments for the discovery of binary and triple asteroids in the near-Earth asteroid (NEA) population. To date, 34 out of 46 known binaries and two ternaries 71% objects total) have been discovered by radar. One of the first discovered and most well studied binary systems is (66391) 1999 KW4 (Ostro et al., 2006). This was the first system with radar evidence for a prominent equatorial bulge, sloped hemispheres, and polar flattening. 1999 KW4 Alpha became a “canonical shape model” for many theoretical studies and numerical simulations on the nature of the binary systems. As the number of binaries detected by radar grew, evidence mounted that not all primaries look like 1999 KW4 Alpha. In fact, (276049) 2002 CE26 (Shepard et al., 2006) and (285263) 1998 QE2 (Springmann et al., 2014) have very rounded shapes without an obvious presence of equatorial ridges. Furthermore, (164121) 2003 YT1 (Nolan et al., in prep.), (1862) Apollo (Ford et al., in prep.), and (363599) 2006 VV2 all have irregular, moderately elongated shapes that show the presence of a bulge at only selected longitudes. All three objects also show elongations of 1.2-1.3, which is still smaller than the mean elongation of ~1.5 in the NEA radar sample. Nevertheless, numerous other primaries have KW4-like shapes such as (185851) 2000 DP107 (Naidu et al., 2011), (311066) 2004 DC (Taylor et al, 2008), and (175706) 1996 FG3 (Benner et al., in prep.). We estimate the abundance of KW4-like objects to be at least 40% of the multiple system population, based on the 41 radar-detected cases. Our results only give the lower bound because not all the dataset have the sufficient SNRs and/or the rotational coverage. Recent Goldstone delay-Doppler images of 2013 WT44 were obtained at nearly pole-on subradar latitude and clearly show evidence of an equatorial bulge, sloped hemispheres, and polar flattening. This has provided one of the strongest arguments to date that KW4-like shapes are real and that they are not artifacts of the shape modeling algorithms. This does not come as a surprise given that KW4-like shapes are strongly motivated by the physics of the rapidly rotating rubble pile.

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.

A cheaper, faster, better way to detect water of hydration on Solar System bodies

NASA Technical Reports Server (NTRS)

Vilas, Faith

1994-01-01

The 3.0-micrometers water of hydration absorption feature observed in the IR photometry of many low-albedo and some medium-albedo asteroids strongly correlates with the 0.7-micrometers Fe(+2) to Fe(+3) oxidized iron absorption feature observed in narrowband spectrophotometry of these asteroids. Using this relationship, an empirical algorithm for predicting the presence of water of hydration in the surface material of a Solar System body using photometry obtained through the Eight-Color Asteroid Survey nu (0.550 micrometers), w (0.701 micrometers), and x (0.853 micrometers) filters was developed and applied to the ECAS photometry of asteroids and outer planet satellites. The percentage of objects in low-albedo, outer main-belt asteroid classes that test positively for water of hydration increases from P to B to C to G class and correlates linearly with the increasing mean albedos of those objects testing positively. The medium-albedo M-class asteroids do not test positively in large number using this algorithm. Aqueously altered asteroids dominate the Solar System population between heliocentric distances of 2.6 to 3.5 AU, bracketing the Solar System region where the aqueous alteration mechanism operated most strongly. One jovian satellite, J VI Himalia, and one saturnian satellite. Phoebe, tested positively for water of hydration, supporting the hypothesis that these may be captured C-class asteroids from a postaccretional dispersion. The proposed testing technique could be applied to an Earth-based survey of asteroids or a space-probe study of an asteroid's surface characteristic in order to identify a potential water source.

A cheaper, faster, better way to detect water of hydration on Solar System bodies

NASA Astrophysics Data System (ADS)

Vilas, Faith

1994-10-01

The 3.0-micrometers water of hydration absorption feature observed in the IR photometry of many low-albedo and some medium-albedo asteroids strongly correlates with the 0.7-micrometers Fe(+2) to Fe(+3) oxidized iron absorption feature observed in narrowband spectrophotometry of these asteroids. Using this relationship, an empirical algorithm for predicting the presence of water of hydration in the surface material of a Solar System body using photometry obtained through the Eight-Color Asteroid Survey nu (0.550 micrometers), w (0.701 micrometers), and x (0.853 micrometers) filters was developed and applied to the ECAS photometry of asteroids and outer planet satellites. The percentage of objects in low-albedo, outer main-belt asteroid classes that test positively for water of hydration increases from P to B to C to G class and correlates linearly with the increasing mean albedos of those objects testing positively. The medium-albedo M-class asteroids do not test positively in large number using this algorithm. Aqueously altered asteroids dominate the Solar System population between heliocentric distances of 2.6 to 3.5 AU, bracketing the Solar System region where the aqueous alteration mechanism operated most strongly. One jovian satellite, J VI Himalia, and one saturnian satellite. Phoebe, tested positively for water of hydration, supporting the hypothesis that these may be captured C-class asteroids from a postaccretional dispersion. The proposed testing technique could be applied to an Earth-based survey of asteroids or a space-probe study of an asteroid's surface characteristic in order to identify a potential water source.

Asteroid impacts on terrestrial planets: the effects of super-Earths and the role of the ν6 resonance

NASA Astrophysics Data System (ADS)

Smallwood, Jeremy L.; Martin, Rebecca G.; Lepp, Stephen; Livio, Mario

2018-01-01

With N-body simulations of a planetary system with an asteroid belt, we investigate how the asteroid impact rate on the Earth is affected by the architecture of the planetary system. We find that the ν6 secular resonance plays an important role in the asteroid collision rate with the Earth. Compared to exoplanetary systems, the Solar system is somewhat special in its lack of a super-Earth mass planet in the inner Solar system. We therefore first consider the effects of the presence of a super-Earth in the terrestrial planet region. We find a significant effect for super-Earths with a mass of around 10 M⊕ and a separation greater than about 0.7 au. For a super-Earth which is interior to the Earth's orbit, the number of asteroids colliding with Earth increases the closer the super-Earth is to the Earth's orbit. This is the result of multiple secular resonance locations causing more asteroids to be perturbed on to Earth-crossing orbits. When the super-Earth is placed exterior to Earth's orbit, the collision rate decreases substantially because the ν6 resonance no longer exists in the asteroid belt region. We also find that changing the semimajor axis of Saturn leads to a significant decrease in the asteroid collision rate, though increasing its mass increases the collision rate. These results may have implications for the habitability of exoplanetary systems.

Speckle interferometry applied to asteroids and other solar system objects

NASA Technical Reports Server (NTRS)

Drummond, J. D.; Hege, E. K.

1985-01-01

The application of speckle interferometry to asteroids and other solar system objects is discussed. The assumption of a triaxial ellipsoid rotating about its shortest axis is the standard model. Binary asteroids, 433 Eros, 532 Herculina, 511 Davida, and Pallas are discussed.

Epsilon Eridani Inner Asteroid Belt

NASA Image and Video Library

2017-09-14

SCI2017_0004: Artist's illustration of the Epsilon Eridani system showing Epsilon Eridani b, right foreground, a Jupiter-mass planet orbiting its parent star at the outside edge of an asteroid belt. In the background can be seen another narrow asteroid or comet belt plus an outermost belt similar in size to our solar system's Kuiper Belt. The similarity of the structure of the Epsilon Eridani system to our solar system is remarkable, although Epsilon Eridani is much younger than our sun. SOFIA observations confirmed the existence of the asteroid belt adjacent to the orbit of the Jovian planet. Credit: NASA/SOFIA/Lynette Cook

Lunar and Planetary Science XXXV: Asteroids, Meteors, Comets

NASA Technical Reports Server (NTRS)

2004-01-01

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.

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.

Solar System evolution from compositional mapping of the asteroid belt.

PubMed

DeMeo, F E; Carry, B

2014-01-30

Advances in the discovery and characterization of asteroids over the past decade have revealed an unanticipated underlying structure that points to a dramatic early history of the inner Solar System. The asteroids in the main asteroid belt have been discovered to be more compositionally diverse with size and distance from the Sun than had previously been known. This implies substantial mixing through processes such as planetary migration and the subsequent dynamical processes.

Evolution of the inner asteroid belt: Paradigms and paradoxes from spectral studies

NASA Technical Reports Server (NTRS)

Gaffey, Michael J.

1987-01-01

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.

Both size-frequency distribution and sub-populations of the main-belt asteroid population are consistent with YORP-induced rotational fission

NASA Astrophysics Data System (ADS)

Jacobson, S.; Scheeres, D.; Rossi, A.; Marzari, F.; Davis, D.

2014-07-01

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}.

Science case for the Asteroid Impact Mission (AIM): A component of the Asteroid Impact & Deflection Assessment (AIDA) mission

NASA Astrophysics Data System (ADS)

Michel, Patrick; Cheng, A.; Küppers, M.; Pravec, P.; Blum, J.; Delbo, M.; Green, S. F.; Rosenblatt, P.; Tsiganis, K.; Vincent, J. B.; Biele, J.; Ciarletti, V.; Hérique, A.; Ulamec, S.; Carnelli, I.; Galvez, A.; Benner, L.; Naidu, S. P.; Barnouin, O. S.; Richardson, D. C.; Rivkin, A.; Scheirich, P.; Moskovitz, N.; Thirouin, A.; Schwartz, S. R.; Campo Bagatin, A.; Yu, Y.

2016-06-01

The Asteroid Impact & Deflection Assessment (AIDA) mission is a joint cooperation between European and US space agencies that consists of two separate and independent spacecraft that will be launched to a binary asteroid system, the near-Earth asteroid Didymos, to test the kinetic impactor technique to deflect an asteroid. The European Asteroid Impact Mission (AIM) is set to rendezvous with the asteroid system to fully characterize the smaller of the two binary components a few months prior to the impact by the US Double Asteroid Redirection Test (DART) spacecraft. AIM is a unique mission as it will be the first time that a spacecraft will investigate the surface, subsurface, and internal properties of a small binary near-Earth asteroid. In addition it will perform various important technology demonstrations that can serve other space missions. The knowledge obtained by this mission will have great implications for our understanding of the history of the Solar System. Having direct information on the surface and internal properties of small asteroids will allow us to understand how the various processes they undergo work and transform these small bodies as well as, for this particular case, how a binary system forms. Making these measurements from up close and comparing them with ground-based data from telescopes will also allow us to calibrate remote observations and improve our data interpretation of other systems. With DART, thanks to the characterization of the target by AIM, the mission will be the first fully documented impact experiment at asteroid scale, which will include the characterization of the target's properties and the outcome of the impact. AIDA will thus offer a great opportunity to test and refine our understanding and models at the actual scale of an asteroid, and to check whether the current extrapolations of material strength from laboratory-scale targets to the scale of AIDA's target are valid. Moreover, it will offer a first check of the validity of the kinetic impactor concept to deflect a small body and lead to improved efficiency for future kinetic impactor designs. This paper focuses on the science return of AIM, the current knowledge of its target from ground-based observations, and the instrumentation planned to get the necessary data.

Momentum harvesting techniques for solar system travel

NASA Technical Reports Server (NTRS)

Willoughby, Alan J.

1991-01-01

Astronomers are lately estimating there are 400,000 earth visiting asteroids larger than 100 meters in diameter. These asteroids are uniquely accessible sources of building materials, propellants, oxygen, water, and minerals. They also constitute a huge momentum reserve, potentially usable for travel throughout the solar system. To use this momentum, these stealthy objects must be tracked and the ability to extract the desired momentum obtained. Momentum harvesting by momentum transfer from asteroid to spacecraft, and by using the momentum of the extraterrestrial material to help deliver itself to its destination is discussed. The purpose is neither to quantify nor justify the momentum exchange processes, but to stimulate collective imaginations with some intriguing possibilities which emerge when momentum as well as material is considered. A net and tether concept is the suggested means of asteroid capture, the basic momentum exchange process. The energy damping characteristics of the tether determines the velocity mismatch that can be tolerated, and hence the amount of momentum that can be harvested per capture. As the tether plays out of its reel, drag on the tether steadily accelerates the spacecraft and dilutes, in time, the would-be collision. A variety of concepts for riding and using asteroids after capture are introduced. The hitchhiker uses momentum transfer only. The beachcomber, the caveman, the swinger, the prospector, and the rock wrecker also take advantage of raw asteroid materials. The chemist and the hijacker go further, they process the asteroid into propellants. Or, an asteroid railway system could be constructed with each hijacked asteroid becoming a scheduled train. Travelers could board this space railway system assured that water, oxygen propellants, and shielding await them. Austere space travel could give way to comforts, with a speed and economy impossible without nature's gift of earth visiting asteroids.

A record of planet migration in the main asteroid belt.

PubMed

Minton, David A; Malhotra, Renu

2009-02-26

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.

The Asteroid Impact Mission - Deflection Demonstration (AIM - D2)

NASA Astrophysics Data System (ADS)

Küppers, M.; Michel, P.; Carnelli, I.

2017-09-01

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.

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.

PERIODIC ORBIT FAMILIES IN THE GRAVITATIONAL FIELD OF IRREGULAR-SHAPED BODIES

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

Jiang, Yu; Baoyin, Hexi, E-mail: jiangyu_xian_china@163.com

The discovery of binary and triple asteroids in addition to the execution of space missions to minor celestial bodies in the past several years have focused increasing attention on periodic orbits around irregular-shaped celestial bodies. In the present work, we adopt a polyhedron shape model for providing an accurate representation of irregular-shaped bodies and employ the model to calculate their corresponding gravitational and effective potentials. We also investigate the characteristics of periodic orbit families and the continuation of periodic orbits. We prove a fact, which provides a conserved quantity that permits restricting the number of periodic orbits in a fixedmore » energy curved surface about an irregular-shaped body. The collisions of Floquet multipliers are maintained during the continuation of periodic orbits around the comet 1P/Halley. Multiple bifurcations in the periodic orbit families about irregular-shaped bodies are also discussed. Three bifurcations in the periodic orbit family have been found around the asteroid 216 Kleopatra, which include two real saddle bifurcations and one period-doubling bifurcation.« less

Evolutionary Pathways for Asteroid Satellites

NASA Astrophysics Data System (ADS)

Jacobson, Seth Andrew

2015-08-01

The YORP-induced rotational fission hypothesis is a proposed mechanism for the creation of small asteroid binaries, which make up approximately 1/6-th of the near-Earth asteroid and small Main Belt asteroid populations. The YORP effect is a radiative torque that rotationally accelerates asteroids on timescales of thousands to millions of years. As asteroids rotationally accelerate, centrifugal accelerations on material within the body can match gravitational accelerations holding that material in place. When this occurs, that material goes into orbit. Once in orbit that material coalesces into a companion that undergoes continued dynamical evolution.Observations with radar, photometric and direct imaging techniques reveal a diverse array of small asteroid satellites. These systems can be sorted into a number of morphologies according to size, multiplicity of members, dynamical orbit and spin states, and member shapes. For instance, singly synchronous binaries have short separation distances between the two members, rapidly rotating oblate primary members, and tidally locked prolate secondary members. Other confirmed binary morphologies include doubly synchronous, tight asynchronous and wide asynchronous binaries. Related to these binary morphologies are unbound paired asteroid systems and bi-lobate contact binaries.A critical test for the YORP-induced rotational fission hypothesis is whether the binary asteroids produced evolve to the observed binary and related systems. In this talk I will review how this evolution is believed to occur according to gravitational dynamics, mutual body tides and the binary YORP effect.

The origin of planetary impactors in the inner solar system.

PubMed

Strom, Robert G; Malhotra, Renu; Ito, Takashi; Yoshida, Fumi; Kring, David A

2005-09-16

Insights into the history of the inner solar system can be derived from the impact cratering record of the Moon, Mars, Venus, and Mercury and from the size distributions of asteroid populations. Old craters from a unique period of heavy bombardment that ended approximately 3.8 billion years ago were made by asteroids that were dynamically ejected from the main asteroid belt, possibly due to the orbital migration of the giant planets. The impactors of the past approximately 3.8 billion years have a size distribution quite different from that of the main belt asteroids but very similar to that of near-Earth asteroids.

Planetary geology: Impact processes on asteroids

NASA Technical Reports Server (NTRS)

Chapman, C. R.; Davis, D. R.; Greenberg, R.; Weidenschilling, S. J.

1982-01-01

The fundamental geological and geophysical properties of asteroids were studied by theoretical and simulation studies of their collisional evolution. Numerical simulations incorporating realistic physical models were developed to study the collisional evolution of hypothetical asteroid populations over the age of the solar system. Ideas and models are constrained by the observed distributions of sizes, shapes, and spin rates in the asteroid belt, by properties of Hirayama families, and by experimental studies of cratering and collisional phenomena. It is suggested that many asteroids are gravitationally-bound "rubble piles.' Those that rotate rapidly may have nonspherical quasi-equilibrium shapes, such as ellipsoids or binaries. Through comparison of models with astronomical data, physical properties of these asteroids (including bulk density) are determined, and physical processes that have operated in the solar system in primordial and subsequent epochs are studied.

AIDA: the Asteroid Impact & Deflection Assessment mission

NASA Astrophysics Data System (ADS)

Vincent, Jean-Baptiste

2016-07-01

The Asteroid Impact & Deflection Assessment (AIDA) mission is a joint cooperation between European and US space agencies that consists of two separate and independent spacecraft that will be launched to a binary asteroid system, the near-Earth asteroid Didymos, to assess the possibility of deflecting an asteroid trajectory by using a kinetic impactor. The European Asteroid Impact Mission (AIM) is under Phase A/B1 study at ESA from March 2015 until summer 2016. AIM is set to rendez-vous with the asteroid system a few months prior to the impact by the US Double Asteroid Redirection Test (DART) spacecraft to fully characterize the smaller of the two binary components. AIM is a unique mission as it will be the first time that a spacecraft will investigate the surface, subsurface, and internal properties of a small binary near Earth asteroid. In addition it will perform various important technology demonstrations that can serve other space missions: AIM will release a set of CubeSats in deep space and a lander on the surface of the smaller asteroid and for the first time, deep-space inter-satellite linking will be demonstrated between the main spacecraft, the CubeSats, and the lander, and data will also be transmitted from interplanetary space to Earth by a laser communication system. The knowledge obtained by this mission will have great implications for our understanding of the history of the Solar System. Small asteroids are believed to result from collisions and other processes (e.g., spinup, shaking) that made them what they are now. Having direct information on their surface and internal properties will allow us to understand how these processes work and transform these small bodies as well as, for this particular case, how a binary system forms. So far, our understanding of the collisional process and the validation of numerical simulations of the impact process rely on impact experiments at laboratory scales. With DART, thanks to the characterization of the target by AIM, the mission will be the first fully documented impact experiment at asteroid scale, which will include the characterization of the target's properties and the outcome of the impact. By comparing our in situ measurements with ground-based data from telescopes, we can calibrate better the remote observations and improve our data interpretation of other systems. Therefore, AIDA offers a unique opportunity to test and refine our understanding and models at the actual scale of an asteroid. This will allow feeding small-body collisional evolution models with more realistic parameters to draw a more reliable story of the Solar System formation and evolution. Moreover, it will offer a first check of the validity of the kinetic impactor concept to deflect a small body trajectory and lead to improved efficiency for future kinetic impactor designs.

Example Solar Electric Propulsion System asteroid tours using variational calculus

NASA Technical Reports Server (NTRS)

Burrows, R. R.

1985-01-01

Exploration of the asteroid belt with a vehicle utilizing a Solar Electric Propulsion System has been proposed in past studies. Some of those studies illustrated multiple asteroid rendezvous with trajectories obtained using approximate methods. Most of the inadequacies of those approximations are overcome in this paper, which uses the calculus of variations to calculate the trajectories and associated payloads of four asteroid tours. The modeling, equations, and solution techniques are discussed, followed by a presentation of the results.

Example Solar Electric Propulsion System asteroid tours using variational calculus

NASA Astrophysics Data System (ADS)

Burrows, R. R.

1985-06-01

Exploration of the asteroid belt with a vehicle utilizing a Solar Electric Propulsion System has been proposed in past studies. Some of those studies illustrated multiple asteroid rendezvous with trajectories obtained using approximate methods. Most of the inadequacies of those approximations are overcome in this paper, which uses the calculus of variations to calculate the trajectories and associated payloads of four asteroid tours. The modeling, equations, and solution techniques are discussed, followed by a presentation of the results.

The Main Asteroid Belt: The Crossroads of the Solar System

NASA Astrophysics Data System (ADS)

Michel, Patrick

2015-08-01

Orbiting the Sun between Mars and Jupiter, main belt asteroids are leftover planetary building blocks that never accreted enough material to become planets. They are therefore keys to understanding how the Solar System formed and evolved. They may also provide clues to the origin of life, as similar bodies may have delivered organics and water to the early Earth.Strong associations between asteroids and meteorites emerged thanks to multi-technique observations, modeling, in situ and sample return analyses. Spacecraft images revolutionized our knowledge of these small worlds. Asteroids are stunning in their diversity in terms of physical properties. Their gravity varies by more orders of magnitude than its variation among the terrestrial planets, including the Moon. Each rendezvous with an asteroid thus turned our geological understanding on its head as each asteroid is affected in different ways by a variety of processes such as landslides, faulting, and impact cratering. Composition also varies, from ice-rich to lunar-like to chondritic.Nearly every asteroid we see today, whether of primitive or evolved compositions, is the product of a complex history involving accretion and one or more episodes of catastrophic disruption that sometimes resulted in families of smaller asteroids that have distinct and indicative petrogenic relationships. These families provide the best data to study the impact disruption process at scales far larger than those accessible in laboratory. Tens, perhaps hundreds, of early asteroids grew large enough to thermally differentiate. Their traces are scattered pieces of their metal-rich cores and, more rarely, their mantles and crusts.Asteroids represent stages on the rocky road to planet formation. They have great stories to tell about the formation and evolution of our Solar System as well as other planetary systems: asteroid belts seem common around Sun-like stars. We will review our current knowledge on their properties, their link to other populations in the different parts of the Solar System, and the space missions devoted to these tracers of our origins, which, for a small fraction, are also potentially hazardous.

Trojan Asteroid Lightcurves: Probing Internal Structure and the Origins

NASA Astrophysics Data System (ADS)

Ryan, E. L.

2017-12-01

Studies of the small bodies of the solar system reveal important clues about the condensation and formation of planetesimal bodies, and ultimately planets in planetary systems. Dynamics of small bodies have been utilized to model giant planet migration within our solar system, colors have been used to explore compositional gradients within the protoplanetary disk, & studies of the size-frequency distribution of main belt asteroids may reveal compositional dependences on planetesimal strength limiting models of planetary growth from collisional aggregration. Studies of the optical lightcurves of asteroids also yield important information on shape and potential binarity of asteroidal bodies. The K2 mission has allowed for the unprecedented collection of Trojan asteroid lightcurves on a 30 minute cadence for baselines of 10 days, in both the L4 and L5 Trojan clouds. Preliminary results from the K2 mission suggest that Trojan asteroids have bulk densities of 1 g/cc and a binary fraction ≤ 33 percent (Ryan et al., 2017, Astronomical Journal, 153, 116), however Trojan lightcurve data is actively being collected via the continued K2 mission. We will present updated results of bulk density and binary fraction of the Trojan asteroids and compare these results to other small body populations, including Hilda asteroids, transNeptunian objects and comet nuclei to test dynamical models of the origins of these populations.

Optimised low-thrust mission to the Atira asteroids

NASA Astrophysics Data System (ADS)

Di Carlo, Marilena; Romero Martin, Juan Manuel; Ortiz Gomez, Natalia; Vasile, Massimiliano

2017-04-01

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.

Long-term influence of asteroids on planet longitudes and chaotic dynamics of the solar system

NASA Astrophysics Data System (ADS)

Woillez, E.; Bouchet, F.

2017-11-01

Over timescales much longer than an orbital period, the solar system exhibits large-scale chaotic behavior and can thus be viewed as a stochastic dynamical system. The aim of the present paper is to compare different sources of stochasticity in the solar system. More precisely we studied the importance of the long term influence of asteroids on the chaotic dynamics of the solar system. We show that the effects of asteroids on planets is similar to a white noise process, when those effects are considered on a timescale much larger than the correlation time τϕ ≃ 104 yr of asteroid trajectories. We computed the timescale τe after which the effects of the stochastic evolution of the asteroids lead to a loss of information for the initial conditions of the perturbed Laplace-Lagrange secular dynamics. The order of magnitude of this timescale is precisely determined by theoretical argument, and we find that τe ≃ 104 Myr. Although comparable to the full main-sequence lifetime of the sun, this timescale is considerably longer than the Lyapunov time τI ≃ 10 Myr of the solar system without asteroids. This shows that the external sources of chaos arise as a small perturbation in the stochastic secular behavior of the solar system, rather due to intrinsic chaos.

Constraining Binary Asteroid Mass Distributions Based On Mutual Motion

NASA Astrophysics Data System (ADS)

Davis, Alex B.; Scheeres, Daniel J.

2017-06-01

The mutual gravitational potential and torques of binary asteroid systems results in a complex coupling of attitude and orbital motion based on the mass distribution of each body. For a doubly-synchronous binary system observations of the mutual motion can be leveraged to identify and measure the unique mass distributions of each body. By implementing arbitrary shape and order computation of the full two-body problem (F2BP) equilibria we study the influence of asteroid asymmetries on separation and orientation of a doubly-synchronous system. Additionally, simulations of binary systems perturbed from doubly-synchronous behavior are studied to understand the effects of mass distribution perturbations on precession and nutation rates such that unique behaviors can be isolated and used to measure asteroid mass distributions. We apply our investigation to the Trojan binary asteroid system 617 Patroclus and Menoetius (1906 VY), which will be the final flyby target of the recently announced LUCY Discovery mission in March 2033. This binary asteroid system is of particular interest due to the results of a recent stellar occultation study (DPS 46, id.506.09) that suggests the system to be doubly-synchronous and consisting of two-similarly sized oblate ellipsoids, in addition to suggesting the presence mass asymmetries resulting from an impact crater on the southern limb of Menoetius.

An interstellar origin for Jupiter's retrograde co-orbital asteroid

NASA Astrophysics Data System (ADS)

Namouni, F.; Morais, M. H. M.

2018-06-01

Asteroid (514107) 2015 BZ509 was discovered recently in Jupiter's co-orbital region with a retrograde motion around the Sun. The known chaotic dynamics of the outer Solar system have so far precluded the identification of its origin. Here, we perform a high-resolution statistical search for stable orbits and show that asteroid (514107) 2015 BZ509 has been in its current orbital state since the formation of the Solar system. This result indicates that (514107) 2015 BZ509 was captured from the interstellar medium 4.5 billion years in the past as planet formation models cannot produce such a primordial large-inclination orbit with the planets on nearly coplanar orbits interacting with a coplanar debris disc that must produce the low-inclination small-body reservoirs of the Solar system such as the asteroid and Kuiper belts. This result also implies that more extrasolar asteroids are currently present in the Solar system on nearly polar orbits.

Lifetime of a spacecraft around a synchronous system of asteroids using a dipole model

NASA Astrophysics Data System (ADS)

dos Santos, Leonardo Barbosa Torres; de Almeida Prado, Antonio F. Bertachini; Sanchez, Diogo Merguizo

2017-11-01

Space missions allow us to expand our knowledge about the origin of the solar system. It is believed that asteroids and comets preserve the physical characteristics from the time that the solar system was created. For this reason, there was an increase of missions to asteroids in the past few years. To send spacecraft to asteroids or comets is challenging, since these objects have their own characteristics in several aspects, such as size, shape, physical properties, etc., which are often only discovered after the approach and even after the landing of the spacecraft. These missions must be developed with sufficient flexibility to adjust to these parameters, which are better determined only when the spacecraft reaches the system. Therefore, conducting a dynamic investigation of a spacecraft around a multiple asteroid system offers an extremely rich environment. Extracting accurate information through analytical approaches is quite challenging and requires a significant number of restrictive assumptions. For this reason, a numerical approach to the dynamics of a spacecraft in the vicinity of a binary asteroid system is offered in this paper. In the present work, the equations of the Restricted Synchronous Four-Body Problem (RSFBP) are used to model a binary asteroid system. The main objective of this work is to construct grids of initial conditions, which relates semi-major axis and eccentricity, in order to quantify the lifetime of a spacecraft when released close to the less massive body of the binary system (modeled as a rotating mass dipole). We performed an analysis of the lifetime of the spacecraft considering several mass ratios of a binary system of asteroids and investigating the behavior of a spacecraft in the vicinity of this system. We analyze direct and retrograde orbits. This study investigated orbits that survive for at least 500 orbital periods of the system (which is approximately one year), then not colliding or escaping from the system during this time. In this work, we take into account the gravitational forces of the binary asteroid system and the solar radiation pressure (SRP). We found several regions where the direct and retrograde orbits of a spacecraft survive throughout the integration time (one year) when the solar radiation pressure is taken into account. Numerical evidence shows that retrograde orbits have a larger region initial conditions that generate orbits that survive for one year, compared to direct orbits.

Speckle interferometry applied to asteroids and other solar system objects

NASA Technical Reports Server (NTRS)

Drummond, J. D.; Hege, E. K.

1986-01-01

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.

Depletion of the Outer Asteroid Belt

PubMed

Liou; Malhotra

1997-01-17

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.

Depletion of the Outer Asteroid Belt

NASA Technical Reports Server (NTRS)

Liou, Jer-Chyi; Malhotra, Renu

1997-01-01

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.

Evidence for the late formation of hydrous asteroids from young meteoritic carbonates.

PubMed

Fujiya, Wataru; Sugiura, Naoji; Hotta, Hideyuki; Ichimura, Koji; Sano, Yuji

2012-01-17

The accretion of small bodies in the Solar System is a fundamental process that was followed by planet formation. Chronological information of meteorites can constrain when asteroids formed. Secondary carbonates show extremely old (53)Mn-(53)Cr radiometric ages, indicating that some hydrous asteroids accreted rapidly. However, previous studies have failed to define accurate Mn/Cr ratios; hence, these old ages could be artefacts. Here we develop a new method for accurate Mn/Cr determination, and report a reliable age of 4,563.4+0.4/-0.5 million years ago for carbonates in carbonaceous chondrites. We find that these carbonates have identical ages, which are younger than those previously estimated. This result suggests the late onset of aqueous activities in the Solar System. The young carbonate age cannot be explained if the parent asteroid accreted within 3 million years after the birth of the Solar System. Thus, we conclude that hydrous asteroids accreted later than differentiated and metamorphosed asteroids.

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.

A Cubesat Asteroid Mission: Propulsion Trade-offs

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Oleson, Steven R.; McGuire, Melissa L.; Bur, Michael J.; Burke, Laura M.; Fittje, James E.; Kohout, Lisa L.; Fincannon, James; Packard, Thomas W.; Martini, Michael C.

2014-01-01

A conceptual design was performed for a 6-U cubesat for a technology demonstration to be launched on the NASA Space Launch System (SLS) test launch EM-1, to be launched into a free-return translunar trajectory. The mission purpose was to demonstrate use of electric propulsion systems on a small satellite platform. The candidate objective chosen was a mission to visit a Near-Earth asteroid. Both asteroid fly-by and asteroid rendezvous missions were analyzed. Propulsion systems analyzed included cold-gas thruster systems, Hall and ion thrusters, incorporating either Xenon or Iodine propellant, and an electrospray thruster. The mission takes advantage of the ability of the SLS launch to place it into an initial trajectory of C3=0.

Primary Surface Particle Motion as a Mechanism for YORP-Driven Binary Asteroid Evolution

NASA Astrophysics Data System (ADS)

Fahnestock, Eugene G.; Scheeres, D. J.

2008-09-01

Within the largest class of binary asteroid systems -- asynchronous binaries typified by 1999 KW4 -- we hypothesize continued YORP spin-up of the rapidly rotating primary leads to recurring episodic lofting motion of primary equator regolith. We theorize this is a mechanism for transporting YORP-injected angular momentum from primary spin into the mutual orbit. This both enables binary primaries to continue to spin at near surface fission rates and produces continued orbit expansion on time scales several times faster than expansion predicted by tidal dissipation alone. This is distinct from the Binary Yorp (BYORP) phenomenon, not studied in this work but to be added to it later. We evaluate our hypotheses using a combination of techniques for an example binary system. First high-fidelity dynamic simulation of surface-originating particles in the full-detail gravity field of the binary components, themselves propagated according to the full two body problem, gives particle final disposition (return impact, transfer impact, escape). Trajectory end states found for regolith lofted at different initial primary spin rates and relative poses are collected into probability matrices, allowing probabilistic propagation of surface particles for long durations at low computational cost. We track changes to mass, inertia dyad, rotation state, and centroid position and velocity for each component in response to this mapped particle motion. This allows tracking of primary, secondary, and mutual orbit angular momenta over time, clearly demonstrating the angular momentum transfer mechanism and validating our hypotheses. We present current orbit expansion rates and estimated orbit size doubling times consistent with this mechanism, for a few binary systems. We also discuss ramifications of this type of rapid binary evolution towards separation, including the frequency with which "divorced binaries" on similar heliocentric orbits are produced, formation of triple systems such as 2001 SN263, and separation timescale dependence on heliocentric distance.

Dust motions in quasi-statically charged binary asteroid systems

NASA Astrophysics Data System (ADS)

Maruskin, Jared M.; Bellerose, Julie; Wong, Macken; Mitchell, Lara; Richardson, David; Mathews, Douglas; Nguyen, Tri; Ganeshalingam, Usha; Ma, Gina

2013-03-01

In this paper, we discuss dust motion and investigate possible mass transfer of charged particles in a binary asteroid system, in which the asteroids are electrically charged due to solar radiation. The surface potential of the asteroids is assumed to be a piecewise function, with positive potential on the sunlit half and negative potential on the shadow half. We derive the nonautonomous equations of motion for charged particles and an analytic representation for their lofting conditions. Particle trajectories and temporary relative equilibria are examined in relation to their moving forbidden regions, a concept we define and discuss. Finally, we use a Monte Carlo simulation for a case study on mass transfer and loss rates between the asteroids.

Rotational breakup as the origin of small binary asteroids.

PubMed

Walsh, Kevin J; Richardson, Derek C; Michel, Patrick

2008-07-10

Asteroids with satellites are observed throughout the Solar System, from subkilometre near-Earth asteroid pairs to systems of large and distant bodies in the Kuiper belt. The smallest and closest systems are found among the near-Earth and small inner main-belt asteroids, which typically have rapidly rotating primaries and close secondaries on circular orbits. About 15 per cent of near-Earth and main-belt asteroids with diameters under 10 km have satellites. The mechanism that forms such similar binaries in these two dynamically different populations was hitherto unclear. Here we show that these binaries are created by the slow spinup of a 'rubble pile' asteroid by means of the thermal YORP (Yarkovsky-O'Keefe-Radzievskii-Paddack) effect. We find that mass shed from the equator of a critically spinning body accretes into a satellite if the material is collisionally dissipative and the primary maintains a low equatorial elongation. The satellite forms mostly from material originating near the primary's surface and enters into a close, low-eccentricity orbit. The properties of binaries produced by our model match those currently observed in the small near-Earth and main-belt asteroid populations, including 1999 KW(4) (refs 3, 4).

Rotational breakup as the origin of small binary asteroids

NASA Astrophysics Data System (ADS)

Walsh, Kevin J.; Richardson, Derek C.; Michel, Patrick

2008-07-01

Asteroids with satellites are observed throughout the Solar System, from subkilometre near-Earth asteroid pairs to systems of large and distant bodies in the Kuiper belt. The smallest and closest systems are found among the near-Earth and small inner main-belt asteroids, which typically have rapidly rotating primaries and close secondaries on circular orbits. About 15 per cent of near-Earth and main-belt asteroids with diameters under 10km have satellites. The mechanism that forms such similar binaries in these two dynamically different populations was hitherto unclear. Here we show that these binaries are created by the slow spinup of a `rubble pile' asteroid by means of the thermal YORP (Yarkovsky-O'Keefe-Radzievskii-Paddack) effect. We find that mass shed from the equator of a critically spinning body accretes into a satellite if the material is collisionally dissipative and the primary maintains a low equatorial elongation. The satellite forms mostly from material originating near the primary's surface and enters into a close, low-eccentricity orbit. The properties of binaries produced by our model match those currently observed in the small near-Earth and main-belt asteroid populations, including 1999KW4 (refs 3, 4).

Dynamical and Physical Properties of 65803 Didymos, the AIDA Mission Target

NASA Astrophysics Data System (ADS)

Campo Bagatin, A.; Richardson, D. C.; Tsiganis, K.; Cheng, A. F.; Michel, P.

2017-09-01

The near-Earth asteroid (NEA) 65803 Didymos is a binary system and is the target of the proposed Asteroid Impact & Deflection Assessment (AIDA) mission, which combines an orbiter (Asteroid Impact Mission, AIM, or the reduced-scope AIM Deflection Demonstration, AIM-D2) [1, 2] and a kinetic impactor experiment (Double Asteroid Redirection Test, DART) planned to impact the secondary of the Didymos binary system in October, 2022 [3]. The Dynamical and Physical Properties of Didymos Working Group supports the AIDA mission by addressing questions related to understanding the dynamical state of the system and inferring the physical properties of the components

Direct and indirect capture of near-Earth asteroids in the Earth-Moon system

NASA Astrophysics Data System (ADS)

Tan, Minghu; McInnes, Colin; Ceriotti, Matteo

2017-09-01

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.

Dynamical evolution of small bodies in the Solar System

NASA Astrophysics Data System (ADS)

Jacobson, Seth A.

2012-05-01

This thesis explores the dynamical evolution of small bodies in the Solar System. It focuses on the asteroid population but parts of the theory can be applied to other systems such as comets or Kuiper Belt objects. Small is a relative term that refers to bodies whose dynamics can be significantly perturbed by non-gravitational forces and tidal torques on timescales less than their lifetimes (for instance the collisional timescale in the Main Belt asteroid population or the sun impact timescale for the near-Earth asteroid population). Non-gravitational torques such as the YORP effect can result in the active endogenous evolution of asteroid systems; something that was not considered more than twenty years ago. This thesis is divided into three independent studies. The first explores the dynamics of a binary systems immediately after formation from rotational fission. The rotational fission hypothesis states that a rotationally torqued asteroid will fission when the centrifugal accelerations across the body exceed gravitational attraction. Asteroids must have very little or no tensile strength for this to occur, and are often referred to as "rubble piles.'' A more complete description of the hypothesis and the ensuing dynamics is provided there. From that study a framework of asteroid evolution is assembled. It is determined that mass ratio is the most important factor for determining the outcome of a rotational fission event. Each observed binary morphology is tied to this evolutionary schema and the relevant timescales are assessed. In the second study, the role of non-gravitational and tidal torques in binary asteroid systems is explored. Understanding the competition between tides and the YORP effect provides insight into the relative abundances of the different binary morphologies and the effect of planetary flybys. The interplay between tides and the BYORP effect creates dramatic evolutionary pathways that lead to interesting end states including stranded widely separated asynchronous binaries or tightly bound synchronous binaries, which occupy a revealing equilibrium. The first results of observations are reported that confirm the theoretically predicted equilibrium. In the final study, the binary asteroid evolutionary model is embedded in a model of the entire Main Belt asteroid population. The asteroid population evolution model includes the effects of collisions as well as the YORP-induced rotational fission. The model output is favorably compared to a number of observables. This allows inferences to be made regarding the free parameters of the model including the most likely typical binary lifetimes. These studies can be combined to create an overall picture of asteroid evolution. From only the power of sunlight, an asteroid can transform into a myriad number of different states according to a few fundamental forces.

Working Group Reports and Presentations: Asteroids

NASA Technical Reports Server (NTRS)

Lewis, John

2006-01-01

The study and utilization of asteroids will be an economical way to enable exploration of the solar system and extend human presence in space. There are thousands of near-earth objects (NEOs) that we will be able to reach. They offer resources, transportation, and exploration platforms, but also present a potential threat to civilization. Asteroids play a catastrophic role in the history of the Earth. Geological records indicate a regular history of massive impacts, which astronomical observations confirm is likely to continue with potentially devastating consequences. However, study and exploration of near earth asteroids can significantly increase advanced warning of an Earth impact, and potentially lead to the technology necessary to avert such a collision. Efforts to detect and prevent cataclysmic events would tend to foster and likely require international cooperation toward a unified goal of self-preservation. Exploration of asteroids will help us to understand our history and perhaps save our future. Besides the obvious and compelling scientific and security drivers for asteroid research and exploration, there are numerous engineering and industrial applications for near-term asteroid exploration. We have strong evidence that some asteroids are metal rich. Some are water and organic rich. They can be reached with a very low fuel cost compared to other solar system destinations. Once we reach them, there are efficient, simple extraction technologies available that would facilitate utilization. In addition, the costs of returning extracted resources from asteroids will be a fraction of the cost to return similar resources from the moon to Low Earth Orbit (LEO). These raw materials, extracted and shipped at relatively low cost, can be used to manufacture structures, fuel, and products which could be used to foster mankind s further exploration of the solar system. Asteroids also have the potential to offer transport to several destinations in the solar system. In addition to Mars and the Asteroid belt, it is possible to nudge the orbits of NEOs to provide convenient transport to other destinations. Resources to support life on these long voyages may be gathered from the host asteroid itself. As asteroids travel over a wide range of inclinations and ranges, they offer possible platforms to perform scientific investigations. These include unique vantage point observations of the sun and planets. These observations can help us to understand solar activity and space weather. They also afford us an opportunity to see how the earth looks from afar with different perspectives. When we look for planets outside of our solar system, these observations will help us to calibrate our data. Asteroids may also be used as platforms to support very long baseline interferometry with unprecedented angular resolutions.

A mission concept for a Grand Tour of Multiple Asteroid Systems

NASA Astrophysics Data System (ADS)

Marchis, F.; Dankanich, J.; Tricarico, P.; Bellerose, J.

2009-12-01

In 1993, the Galileo spacecraft imaged the first companion of asteroid, Dactyl orbiting 243 Ida, a main-belt asteroid. Since then, discoveries have been accumulated thanks to the development of high angular resolution imaging on ground-based telescopes (adaptive optics), radar observations and accurate photometric light curve measurements. To date, 180 companions of small solar system bodies (SSSBs) are known in various populations, including 100 in the asteroid main belt, 33 Near Earth Asteroids, 4 Jupiter-Trojan asteroids and 44 in the Kuiper Belt. Multiple Asteroids have been shown to be complex worlds in their own with a wide range of morphologies, dynamical histories, and structural evolution. To the exception of 243 Ida, no spacecraft has visited any of them. Investigating binary asteroid systems can verify and validate current theories on their formation and on the influence of the sun in their formation (YORP effect) and evolution (space weathering). In particular, assessing the origin of the secondary satellite, if it is of common origin or capture, can provide clue of their formation. To a larger extend, the determination of their nature, scenario formation and evolution are key to understand how planet formation occurred but also to understand i) the population and compositional structure of the SSSB today ii) how the dynamics and collisions modify this structure over time iii) what the physical properties of asteroids are (density, porosity) iv) how the surface modification processes affect our ability to determine this structure (e.g. space weathering). In addition, being able to study these properties on closeby asteroids will give a relative scale accounting for the sizes, shape, rotation periods and cratering rate of these small and young bodies. In the framework of the NASA Discovery program, we propose a mission consisting of a Grand Tour of several multiple asteroid systems, including the flyby of a near earth binary asteroid and the rendezvous with several multiple asteroid systems located in the main belt. This mission concept uses the NASA's evolutionary Xenon Thruster (NEXT), the second generation of electric propulsion with 3 times more input power than the previous generation (NSTAR) of the Dawn mission. The mission objectives for each rendezvous asteroid are i) the characterization of the surface geology by direct imaging in visible and thermal infrared spectroscopy, ii) the characterization of the shape and gravity coupling visible observations with LIDAR ranging data, iii) the determination of the thermophysical properties of the surface, and iv) the identification of the surface composition by visible and near-infrared spectroscopy. The trajectory, science package and mission operations of the mission will be described. This work is supported by the National Science Foundation 05-608, "Astronomy and Astrophysics Research Grants (AAG)" No AST-0807468

Project RAMA: Reconstructing Asteroids Into Mechanical Automata

NASA Technical Reports Server (NTRS)

Dunn, Jason; Fagin, Max; Snyder, Michael; Joyce, Eric

2017-01-01

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.

Compositional Variegation of Large-Diameter Low-Albedo Asteroids

NASA Astrophysics Data System (ADS)

Vilas, F.; Jarvis, K. S.; Anz-Meador, T. D.; Thibault, C. A.; Sawyer, S. R.; Fitzsimmons, A.

1997-07-01

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.

A three-parameter asteroid taxonomy

NASA Technical Reports Server (NTRS)

Tedesco, Edward F.; Williams, James G.; Matson, Dennis L.; Veeder, Glenn J.; Gradie, Jonathan C.

1989-01-01

Broadband U, V, and x photometry together with IRAS asteroid albedos have been used to construct an asteroid classification system. The system is based on three parameters (U-V and v-x color indices and visual geometric albedo), and it is able to place 96 percent of the present sample of 357 asteroids into 11 taxonomic classes. It is noted that all but one of these classes are analogous to those previously found using other classification schemes. The algorithm is shown to account for the observational uncertainties in each of the classification parameters.

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.

V-type asteroids investigation in support to the NASA DAWN mission

NASA Astrophysics Data System (ADS)

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

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.

REVIEWS OF TOPICAL PROBLEMS: Satellites of asteroids

NASA Astrophysics Data System (ADS)

Prokof'eva, Valentina V.; Tarashchuk, V. P.; Gor'kavyi, N. N.

1995-06-01

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.

Lightcurve Analysis of L5 Trojan Asteroids at the Center for Solar System Studies 2017 September to December

NASA Astrophysics Data System (ADS)

Stephens, Robert D.; Warner, Brian D.

2018-04-01

Lightcurves for four Jovian Trojan asteroids were obtained at the Center for Solar System Studies (CS3) from 2017 September to December. From observations in 2016 June, 2759 Idomeneus was found to be another candidate for the special case of very wide binaries. This would be the fifth confirmed Jovian Trojan binary asteroid.

Periodic motion near non-principal-axis rotation asteroids

NASA Astrophysics Data System (ADS)

Shang, Haibin; Wu, Xiaoyu; Qin, Xiao; Qiao, Dong

2017-11-01

The periodic motion near non-principal-axis (NPA) rotation asteroids is proved to be markedly different from that near uniformly rotating bodies due to the complex spin state with precession, raising challenges in terms of the theoretical implications of dynamical systems. This paper investigates the various periodic motions near the typical NPA asteroid 4179 Toutatis, which will contribute to the understanding of the dynamical environments near the widespread asteroids in the Solar system. A novel method with the incorporation of the ellipsoid-mascon gravitational field model and global optimization is developed to efficiently locate periodic solutions in the system. The numerical results indicate that abundant periodic orbits appear near the NPA asteroids. These various orbits are theoretically classified into five topological types with special attention paid to the cycle stability. Although the concept of classical family disappears in our results, some orbits with the same topological structure constitute various generalized `families' as the period increases. Among these `families' a total of 4 kinds of relationships between orbits, including rotation, evolution, distortion and quasi-symmetry, are found to construct the global mapping of these types. To cover the rotation statuses of various NPA asteroids, this paper also discusses the variation of periodic orbits with diverse asteroid spin rates, showing that the scales of some orbits expand, shrink or almost annihilate as the system period changes; meanwhile, their morphology and topology remain unchanged.

Photometric constraints on binary asteroid dynamics

NASA Astrophysics Data System (ADS)

Scheirich, Peter

2015-08-01

To date, about 50 binary NEAs, 20 Mars-crossing and 80 small MB asteroids are known. We observe also a population of about 200 unbound asteroid systems (asteroid pairs). I will review the photometric observational data we have for the best observed cases and compare them with theories of binary and paired asteroids evolution.The observed characteristics of asteroid systems suggest their formation by rotational fission of parent rubble-pile asteroids after being spun up by the YORP effect. The angular momentum content of binary asteroids is close to critical. The orientations of satellite orbits of observed binary systems are non-random; the orbital poles concentrate near the obliquities of 0 and 180 degrees, i.e., near the YORP asymptotic states.Recently, a significant excess of retrograde satellite orbits was detected, which is not yet explained characteristic.An evolution of binary system depend heavily on the BYORP effect. If BYORP is contractive, the primary and secondary could end in a tidal-BYORP equilibrium. Observations of mutual events between binary components in at least four apparitions are needed for BYORP to be revealed by detecting a quadratic drift in mean anomaly of the satellite. I will show the observational evidence of single-synchronous binary asteroid with tidally locked satellite (175706 1996 FG3), i.e, with the quadratic drift equal to zero, and binary asteroid with contracting orbit (88710 2001 SL9), with positive value of the quadratic drift (the solution for the quadratic drift is ambiguous so far, with possible values of 5 and 8 deg/yr2).The spin configuration of the satellite play a crucial role in the evolution of the system under the influence of the BYORP effect. I will show that the rotational lightcurves of the satellites show that most of them have small libration amplitudes (up to 20 deg.), with a few interesting exceptions.Acknowledgements: This work has been supported by the Grant Agency of the Czech Republic, Grant P209/12/0229, and by the Ministry of Education of the Czech Republic, Grant LG12001.

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.

Spectral properties of binary asteroids

NASA Astrophysics Data System (ADS)

Pajuelo, Myriam; Birlan, Mirel; Carry, Benoît; DeMeo, Francesca E.; Binzel, Richard P.; Berthier, Jérôme

2018-04-01

We present the first attempt to characterize the distribution of taxonomic class among the population of binary asteroids (15% of all small asteroids). For that, an analysis of 0.8-2.5{μ m} near-infrared spectra obtained with the SpeX instrument on the NASA/IRTF is presented. Taxonomic class and meteorite analog is determined for each target, increasing the sample of binary asteroids with known taxonomy by 21%. Most binary systems are bound in the S-, X-, and C- classes, followed by Q and V-types. The rate of binary systems in each taxonomic class agrees within uncertainty with the background population of small near-Earth objects and inner main belt asteroids, but for the C-types which are under-represented among binaries.

Catching a Rolling Stone: Dynamics and Control of a Spacecraft and an Asteroid

NASA Technical Reports Server (NTRS)

Roithmayr, Carlos M.; Shen, Haijun; Jesick, Mark C; Cornelius, David M

2013-01-01

In a recent report, a robotic spacecraft mission is proposed for the purpose of collecting a small asteroid, or a small part of a large one, and transporting it to an orbit in the Earth-Moon system. Such an undertaking will require solutions to many of the engineering problems associated with deflection of an asteroid that poses a danger to Earth. In both cases, it may be necessary for a spacecraft to approach an asteroid from a nearby position, hover for some amount of time, move with the same angular velocity as the asteroid, descend, perhaps ascend, and finally arrest the angular velocity of the asteroid. Dynamics and control in each of these activities is analyzed in order to determine the velocity increments and control torque that must be provided by a reaction control system, and the mass of the propellant that will be consumed. Two attitude control algorithms are developed, one to deal with synchronizing the spacecraft s angular velocity with that of the asteroid, and the other to arrest the asteroid s angular velocity. A novel approach is proposed for saving fuel in the latter case.

Evaluating Different Scenarios for the Formation and Early Evolution of the Asteroid Belt

NASA Astrophysics Data System (ADS)

O'Brien, David P.; Walsh, Kevin J.

2014-11-01

The asteroid belt is dynamically excited, depleted in mass relative to the surface mass density of the rest of the Solar System, and contains numerous diverse taxonomic classes of asteroids that are partly, but not completely, radially mixed. In the 'classical' scenario of Solar System formation, the excitation, depletion and radial mixing of the asteroid belt is best explained by the effect of planetary embryos that are initially present in the primordial asteroid belt region [1-3]. In the more recent 'Grand Tack' scenario proposed by Walsh et al. [4], the early inward-then-outward migration of Jupiter in the gas disk initially depletes, then repopulates the asteroid belt with material scattered from both interior and exterior to Jupiter. Here we will examine in detail the model asteroid distributions resulting from these two scenarios for a range of parameters, and compare them to observational constraints on the current distribution of asteroids in the Solar System. We will also address the possible effects that late-stage planetesimal-driven migration and resonance-crossing of Jupiter and Saturn in the Nice Model [eg. 5,6] may have on the final asteroid distribution.[1] G.W. Wetherill, Icarus 100, 307-325 (1992)[2] J.-M. Petit et al., Icarus 153, 338-347 (2001)[3] D.P. O'Brien t al., Icarus 191, 434-452 (2007)[4] K.J. Walsh et al., Nature 475, 206-209 (2011)[5] K. Tsiganis et al., Nature 435, 459-461 (2005)[6] A. Morbidelli et al., AJ 140, 1391-1401 (2010)

Meteorite spectroscopy and characterization of asteroid surface materials

NASA Technical Reports Server (NTRS)

Gaffey, Michael J.

1991-01-01

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.

Spacecraft Conceptual Design for Returning Entire Near-Earth Asteroids

NASA Technical Reports Server (NTRS)

Brophy, John R.; Oleson, Steve

2012-01-01

In situ resource utilization (ISRU) in general, and asteroid mining in particular are ideas that have been around for a long time, and for good reason. It is clear that ultimately human exploration beyond low-Earth orbit will have to utilize the material resources available in space. Historically, the lack of sufficiently capable in-space transportation has been one of the key impediments to the harvesting of near-Earth asteroid resources. With the advent of high-power (or order 40 kW) solar electric propulsion systems, that impediment is being removed. High-power solar electric propulsion (SEP) would be enabling for the exploitation of asteroid resources. The design of a 40-kW end-of-life SEP system is presented that could rendezvous with, capture, and subsequently transport a 1,000-metric-ton near-Earth asteroid back to cislunar space. The conceptual spacecraft design was developed by the Collaborative Modeling for Parametric Assessment of Space Systems (COMPASS) team at the Glenn Research Center in collaboration with the Keck Institute for Space Studies (KISS) team assembled to investigate the feasibility of an asteroid retrieval mission. Returning such an object to cislunar space would enable astronaut crews to inspect, sample, dissect, and ultimately determine how to extract the desired materials from the asteroid. This process could jump-start the entire ISRU industry.

AIDA: The Asteroid Impact & Deflection Assessment Mission

NASA Astrophysics Data System (ADS)

Galvez, A.; Carnelli, I.; Michel, P.; Cheng, A. F.; Reed, C.; Ulamec, S.; Biele, J.; Abell, P.; Landis, R.

2013-09-01

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].

Parameter-Study Of The Thermal Yarkovsky Effect Acting On Neas

NASA Astrophysics Data System (ADS)

Polishook, David; Prialnik, D.; Rosenberg, E.; Brosch, N.

2010-10-01

We study the relevant parameters for the thermal Yarkovsky effect acting on Near-Earth Asteroids (NEAs), specifically the rotation period and rotation axis. The study uses a quasi 3-D thermal model to derive the temperature map over the surface of the asteroid, and the thermal thrust is calculated. The model (Prialnik et al. 2004, Rosenberg and Prialnik 2006), uses an implicit scheme to numerically solve the equations that describe the asteroid and its thermal evolution. The results show how the thermal thrust is stronger for fast-rotating asteroids, as heat is emitted from their surface on the evening side, increasing the tangential component of the thermal thrust. Moreover, we show the differences in the thermal thrust between asteroids with different perihelion distances, and how this can explain the observed distribution of asteroids in the inner Solar System on the spin-perihelion plane. Our results suggest that many asteroids within the inner Solar System may have retrograde spins. Acknowledgements: D. Polishook is grateful for an Ilan Ramon doctoral scholarship from the Israeli Ministry of Science.

Reverse Asteroids: Searching for an Effective Tool to Combat Asteroid Belt Misconceptions

NASA Astrophysics Data System (ADS)

Summers, F.; Eisenhamer, B.

2014-12-01

The public 'knows' that asteroid belts are densely packed and dangerous for spaceships to cross. Visuals from "Star Wars" to, unfortunately, the recent "Cosmos" TV series have firmly established this astronomical misconception. However, even scientifically correct graphics, such as the Minor Planet Center's plot of the inner solar system, reinforces that view. Each pixel in the image is more than a million kilometers in width, making an accurate representation of the object density impossible.To address this widespread misconception, we are investigating an educational exercise built around a computer interactive that we call "Reverse Asteroids". In the arcade classic video game, the asteroids came to the player's spaceship. For our reverse implementation, we consider an inquiry-based activity in which the spaceship must go hunting for the asteroids, using a database of real objects in our solar system. Both 3D data visualization and basic statistical analysis play crucial roles in bringing out the true space density within the asteroid belt, and perhaps a reconciliation between imagination and reality. We also emphasize that a partnership of scientists and educators is fundamental to the success of such projects.

Study of binary asteroids with three space missions

NASA Astrophysics Data System (ADS)

Kovalenko, Irina; Doressoundiram, Alain; Hestroffer, Daniel

Binary and multiple asteroids are common in the Solar system and encountered in various places going from Near-Earth region, to the main-belt, Trojans and Centaurs, and beyond Neptune. Their study can provide insight on the Solar System formation and its subsequent dynamical evolution. Binaries are also objects of high interest because they provide fundamental physical parameters such as mass and density, and hence clues on the early Solar System, or other processes that are affecting asteroid over time. We will present our current project on analysis of such systems based on three space missions. The first one is the Herschel space observatory (ESA), the largest infrared telescope ever launched. Thirty Centaurs and trans-Neptunian binaries were observed by Herschel and the measurement allowed to define size, albedo and thermal properties [1]. The second one is the satellite Gaia (ESA). This mission is designed to chart a three-dimensional map of the Galaxy. Gaia will provide positional measurements of Solar System Objects - including asteroid binaries - with unprecedented accuracy [2]. And the third one is the proposed mission AIDA, which would study the effects of crashing a spacecraft into an asteroid [3]. The objectives are to demonstrate the ability to modify the trajectory of an asteroid, to precisely measure its trajectory change, and to characterize its physical properties. The target of this mission is a binary system: (65803) Didymos. This encompasses orbital characterisations for both astrometric and resolved binaries, as well as unbound orbit, study of astrometric binaries, derivation of densities, and general statistical analysis of physical and orbital properties of trans-Neptunian and other asteroid binaries. Acknowledgements : work supported by Labex ESEP (ANR N° 2011-LABX-030) [1] Müller T., Lellouch E., Stansberry J. et al. 2009. TNOs are Cool: A Survey of the Transneptunian Region. EM&P 105, 209-219. [2] Mignard F., Cellino A., Muinonen K. et al. 2007. The Gaia Mission: Expected Applications to Asteroid Science. EM&P 1001, 97-125. [3] Galvez A., Carnelli I. et al. 2013. AIDA: The Asteroid Impact & Deflection Assessment Mission. EPSC 2013 - 1043.

Design of the optical communication system for the asteroid impact mission

NASA Astrophysics Data System (ADS)

Heese, C.; Sodnik, Z.; Carnelli, I.

2017-09-01

The Asteroid Impact Mission (AIM) is part of the joint Asteroid Impact and Deflection Assessment (AIDA) project of ESA, DLR, Observatoire de la Côte d'Ázur, NASA, and Johns Hopkins University Applied Physics Laboratory (JHU/APL).

Experiments on asteroids using hard landers

NASA Technical Reports Server (NTRS)

Turkevich, A.; Economou, T.

1978-01-01

Hard lander missions to asteroids are examined using the Westphal penetrator study as a basis. Imagery and chemical information are considered to be the most significant science to be obtained. The latter, particularly a detailed chemical analysis performed on an uncontaminated sample, may answer questions about the relationships of asteroids to meteorites and the place of asteroids in theories of the formation of the solar system.

Spin vectors of asteroids 21 Lutetia, 196 Philomela, 250 Bettina, 337 Devosa, and 804 Hispania

NASA Technical Reports Server (NTRS)

Michalowski, Tadeusz

1992-01-01

Such parameters as shape, orientation of spin axis, prograde or retrograde rotation are important for understanding the collisional evolution of asteroids since the primordial epochs of solar system history. These parameters remain unknown for most asteroids and poorly constrained for all but a few. This work presents results for five asteroids: 21, 196, 250, 337, and 804.

Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2017 April thru June

NASA Astrophysics Data System (ADS)

Warner, Brian D.

2017-10-01

Lightcurves for 16 main-belt asteroids were obtained at the Center for Solar System Studies-Palmer Divide Station (CS3-PDS) from 2017 April thru June. Many of the asteroids were “strays” in the field of planned targets, demonstrating a good reason for data mining images. Analysis shows that the Hungaria asteroid (45878) 2000 WX29 may be binary.

Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2016 December thru 2017 March

NASA Astrophysics Data System (ADS)

Warner, Brian D.

2017-07-01

Lightcurves for 18 main-belt asteroids were obtained at the Center for Solar System Studies-Palmer Divide Station (CS3-PDS) from 2016 December thru 2017 March. Many of the asteroids were “strays” in the field of planned targets, demonstrating a good reason for data mining images. Analysis shows that the Hungaria asteroid (45878) 2000 WX29 may be binary.

Water in the Early Solar System: Infrared Studies of Aqueously Altered and Minimally Processed Asteroids

NASA Astrophysics Data System (ADS)

McAdam, Margaret M.

This thesis investigates connections between low albedo asteroids and carbonaceous chondrite meteorites using spectroscopy. Meteorites and asteroids preserve information about the early solar system including accretion processes and parent body processes active on asteroids at these early times. One process of interest is aqueous alteration. This is the chemical reaction between coaccreted water and silicates producing hydrated minerals. Some carbonaceous chondrites have experienced extensive interactions with water through this process. Since these meteorites and their parent bodies formed close to the beginning of the Solar System, these asteroids and meteorites may provide clues to the distribution, abundance and timing of water in the Solar nebula at these times. Chapter 2 of this thesis investigates the relationships between extensively aqueously altered meteorites and their visible, near and mid-infrared spectral features in a coordinated spectral-mineralogical study. Aqueous alteration is a parent body process where initially accreted anhydrous minerals are converted into hydrated minerals in the presence of coaccreted water. Using samples of meteorites with known bulk properties, it is possible to directly connect changes in mineralogy caused by aqueous alteration with spectral features. Spectral features in the mid-infrared are found to change continuously with increasing amount of hydrated minerals or degree of alteration. Building on this result, the degrees of alteration of asteroids are estimated in a survey of new asteroid data obtained from SOFIA and IRTF as well as archived the Spitzer Space Telescope data. 75 observations of 73 asteroids are analyzed and presented in Chapter 4. Asteroids with hydrated minerals are found throughout the main belt indicating that significant ice must have been present in the disk at the time of carbonaceous asteroid accretion. Finally, some carbonaceous chondrite meteorites preserve amorphous iron-bearing materials that formed through disequilibrium condensation in the disk. These materials are readily destroyed in parent body processes so their presence indicates the meteorite/asteroid has undergone minimal parent body processes since the time of accretion. Presented in Chapter 3 is the spectral signature of meteorites that preserve significant amorphous iron-bearing materials and the identification of an asteroid, (93) Minerva, that also appears to preserve these materials.

New insights on the main-belt triple asteroid (87) Sylvia

NASA Astrophysics Data System (ADS)

Marchis, Franck; Berthier, J.; Vachier, F.; Durech, J.; Descamps, P.; Carry, B.

2013-10-01

(87) Sylvia is the first minor planet known to possess two moons (Marchis et al. Nature 2005). Combining Adaptive Optics data from 8-10m class telescopes, with lightcurve observations and the result of an exceptional stellar occultation on Jan. 6 2013, we report new insights on the dynamical and physical properties of (87) Sylvia. Based on Keck, Gemini and VLT AO observations collected from 2001 to 2011 we derived the mutual orbits of the system which can be fitted by a simple Kepler model (J2=0). From this model, we predicted the relative positions of the moons at the time of this event with an accuracy better than 10 km on the Earth. 50 observers were mobilized along the path of the event and 16 of them reported an occultation, 4 of them by Romulus, the outer moon of Sylvia. A new non-convex shape model of Sylvia's primary was built (Deq = 270 +/- 3 km, leading to a density of ρ=1.3+/-0.1 g/cm3) from this entire set of data (40 lightcurves, 2 well-resolved Keck AO images, and the occultation timings). The analysis of the chords of Romulus give us the opportunity to show that it has an elongated shape (a/b ~ 2.7), and refine its size (De 24 km). We will discuss the origin of this triple system and the surprising elongated shape of its satellite. This has been supported by the NASA grant NNX11AD62G and grants GACR P209/10/0537 and P209/12/0229 of the Czech Science Foundation, and by the Research Program MSM0021620860.

Surprise! The oft-ignored Moon might actually be important for changing the spins of asteroids during Earth flybys

NASA Astrophysics Data System (ADS)

Tuttle Keane, James; Siu, Hosea C.; Moskovitz, Nicholas A.; Binzel, Richard P.

2015-11-01

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.

Spectral properties of binary asteroids

NASA Astrophysics Data System (ADS)

Pajuelo, Myriam; Birlan, Mirel; Carry, Benoît; DeMeo, Francesca E.; Binzel, Richard P.; Berthier, Jérôme

2018-07-01

We present the first attempt to characterize the distribution of taxonomic class among the population of binary asteroids (15 per cent of all small asteroids). For that, an analysis of 0.8-2.5 µm near-infrared spectra obtained with the SpeX instrument on the NASA/IRTF (Infrared Telescope Facility) is presented. Taxonomic class and meteorite analogue is determined for each target, increasing the sample of binary asteroids with known taxonomy by 21 per cent. Most binary systems are bound in the S, X, and C classes, followed by Q and V types. The rate of binary systems in each taxonomic class agrees within uncertainty with the background population of small near-Earth objects and inner main belt asteroids, but for the C types which are under-represented among binaries.

Scenarios which may lead to the rise of an asteroid-based technical civilisation

NASA Astrophysics Data System (ADS)

Kecskes, Csaba

2002-05-01

In a previous paper, the author described a hypothetical development path of technical civilisations which has the following stages: planet dwellers, asteroid dwellers, interstellar travellers, interstellar space dwellers. In this paper, several scenarios are described which may cause the rise of an asteroid-based technical civilisation. Before such a transition may take place, certain space technologies must be developed fully (now these exist only in very preliminary forms): closed-cycle biological life support systems, space manufacturing systems, electrical propulsion systems. After mastering these technologies, certain events may provide the necessary financial means and social impetus for the foundation of the first asteroid-based colonies. In the first scenario, a rich minority group becomes persecuted and they decide to leave the Earth. In the second scenario, a "cold war"-like situation exists and the leaders of the superpowers order the creation of asteroid-based colonies to show off their empires' technological (and financial) grandiosity. In the third scenario, the basic situation is similar to the second one, but in this case the asteroids are not just occupied by the colonists. With several decades of hard work, an asteroid can be turned into a kinetic energy weapon which can provide the same (or greater) threat as the nuclear arsenal of a present superpower. In the fourth scenario, some military asteroids are moved to Earth-centred orbits and utilised as "solar power satellites" (SPS). This would be a quite economical solution because a "military asteroid" already contains most of the important components of an SPS (large solar collector arrays, power distribution devices, orbit modifying rocket engine), one should add only a large microwave transmitter.

Scenarios which may lead to the rise of an asteroid-based technical civilisation.

PubMed

Kecskes, Csaba

2002-05-01

In a previous paper, the author described a hypothetical development path of technical civilisations which has the following stages: planet dwellers, asteroid dwellers, interstellar travellers, interstellar space dwellers. In this paper, several scenarios are described which may cause the rise of an asteroid-based technical civilisation. Before such a transition may take place, certain space technologies must be developed fully (now these exist only in very preliminary forms): closed-cycle biological life support systems, space manufacturing systems, electrical propulsion systems. After mastering these technologies, certain events may provide the necessary financial means and social impetus for the foundation of the first asteroid-based colonies. In the first scenario, a rich minority group becomes persecuted and they decide to leave the Earth. In the second scenario, a "cold war"-like situation exists and the leaders of the superpowers order the creation of asteroid-based colonies to show off their empires' technological (and financial) grandiosity. In the third scenario, the basic situation is similar to the second one, but in this case the asteroids are not just occupied by the colonists. With several decades of hard work, an asteroid can be turned into a kinetic energy weapon which can provide the same (or greater) threat as the nuclear arsenal of a present superpower. In the fourth scenario, some military asteroids are moved to Earth-centred orbits and utilised as "solar power satellites" (SPS). This would be a quite economical solution because a "military asteroid" already contains most of the important components of an SPS (large solar collector arrays, power distribution devices, orbit modifying rocket engine), one should add only a large microwave transmitter. c2002 Elsevier Science Ltd. All rights reserved.

Shape and spin of asteroid 967 Helionape

NASA Astrophysics Data System (ADS)

Apostolovska, G.; Kostov, A.; Donchev, Z.; Bebekovska, E. Vchkova; Kuzmanovska, O.

2018-04-01

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)).

Origin of Martian Moons from Binary Asteroid Dissociation

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Lyons, Valerie J. (Technical Monitor)

2001-01-01

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.

Sending an Instrument to Psyche, the Largest Metal Asteroid in the Solar System

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

Burks, Morgan

In a few years, an instrument designed and built by Lawrence Livermore National Laboratory researchers will be flying hundreds of millions of miles through space to explore a rare, largely metal asteroid. The Livermore gamma ray spectrometer will be built in collaboration with researchers from the Johns Hopkins Applied Physics Laboratory for the first-ever visit to Psyche, the largest metal asteroid in the solar system.

The asteroid impact mission: testing laser communication in deep-space

NASA Astrophysics Data System (ADS)

Carnelli, I.; Mellab, K.; Heese, C.; Sodnik, Z.; Pesquita, V.; Gutierrez, B.

2017-09-01

In October 2022 the binary asteroid system 65803 Didymos will have an exceptionally close approach with the Earth flying by within only 0.088 AU. ESA is planning to leverage on this close encounter to launch a small mission of opportunity called Asteroid Impact Mission (AIM) to explore and demonstrate new technologies for future science and exploration missions while addressing planetary defence and performing asteroid scientific investigations.

Probable Disastrous Consequences of Collision Between Unknown Small (100 m) Asteroids with Known (Approximately 1 km) Near Earth Orbiting (NEO) Asteroids

NASA Technical Reports Server (NTRS)

Smalley, Larry

2003-01-01

The long-term stability of the Solar System is not well understood. Ironically its stability is taken for granted even though our knowledge of all the constituents [comets, asteroids. (The Asteroid Belt between Mars and Jupiter, Trojan Asteroids, Kuiper belt, Ort Cloud), planetoids, planets, moons, etc], and its long-term dynamics cannot be easily computed. At best one might say that the solar system is chaotic, but much of the time it seems to exists near a quasi-stationary state. An asteroid that passes near the Earth regularly returns with clock-like precision. Taking into account every known detail of its path through the solar system, its orbit is calculated forward thousands of years with no untoward calamity on the horizon. And then one day, this passive visitor slams into the Earth during a sunny afternoon picnic! Can this happen? Unfortunately, this is a real possibility in the ordinary history of the solar system. In fact our knowledge of the solar system in the small is sketchy, as will be pointed out. Events, which lie outside our awareness, can precipitate disasters that we may perceive when it's too late to launch effective counter measures. In this work, one such scenario is described and the direct consequences for the Earth are calculated.

The Physical, Geological, and Dynamical Nature of Asteroid (101955) Bennu - Target of OSIRIS-REx

NASA Astrophysics Data System (ADS)

Lauretta, Dante

2014-11-01

OSIRIS-REx will survey asteroid (101955) Bennu to understand its properties, assess its resource potential, refine the impact hazard, and return a sample to Earth. This mission launches in 2016. Bennu is different from all other near-Earth asteroids previously visited by spacecraft. (433) Eros, target of the NEAR-Shoemaker mission, and (25143) Itokawa, target of Hayabusa, are both high-albedo, S-type asteroids with irregular shapes. In contrast, Bennu has a low albedo, is a B-type asteroid, and has a distinct spheroidal shape. While Eros and Itokawa are similar to ordinary chondrites, Bennu is likely related to carbonaceous chondrites, meteorites that record the history of volatiles and organic compounds in the early Solar System.We performed an extensive campaign to determine the properties of Bennu. This investigation provides information on the orbit, shape, mass, rotation state, radar response, photometric, spectroscopic, thermal, regolith, and environmental properties of Bennu. Combining these data with cosmochemical and dynamical models yields a hypothetical timeline for Bennu’s formation and evolution. Bennu is an ancient object that has witnessed over 4.5 Gyr of Solar System history. Its chemistry and mineralogy were established within the first 10 Myr of the Solar System. It likely originated as a discrete asteroid in the main belt ~0.7 - 2 Gyr ago as a fragment from the catastrophic disruption of a large, carbonaceous asteroid. It was delivered to near-Earth space via a combination of Yarkovsky-induced drift and interaction with giant-planet resonances. During its journey, YORP processes and planetary encounters modified Bennu’s spin state, potentially reshaping and resurfacing the asteroid. Bennu is a Potentially Hazardous Asteroids with an ~1-in-2700 chance of impacting the Earth in the late 22nd century. It will most likely end its dynamical life by falling into the Sun. The highest probability for a planetary impact is with Venus, followed by the Earth. There is a chance that Bennu will be ejected from the inner Solar System after a close encounter with Jupiter. OSIRIS-REx will return samples from this intriguing asteroid in September 2023.

Evidence for a near-Earth asteroid belt

NASA Technical Reports Server (NTRS)

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.

1993-01-01

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.

OSIRIS-REx Asterod Sample Return Mission

NASA Technical Reports Server (NTRS)

Nakamura-Messinger, Keiki; Connolly, Harold C. Jr.; Messenger, Scott; Lauretta, Dante S.

2017-01-01

OSIRIS-REx is NASA's third New Frontiers Program mission, following New Horizons that completed a flyby of Pluto in 2015 and the Juno mission to Jupiter that has just begun science operations. The OSIRIS-REx mission's primary objective is to collect pristine surface samples of a carbonaceous asteroid and return to Earth for analysis. Carbonaceous asteroids and comets are 'primitive' bodies that preserved remnants of the Solar System starting materials and through their study scientists can learn about the origin and the earliest evolution of the Solar System. The OSIRIS-REx spacecraft was successfully launched on September 8, 2016, beginning its seven year journey to asteroid 101955 Bennu. The robotic arm will collect 60-2000 grams of material from the surface of Bennu and will return to Earth in 2023 for worldwide distribution by the Astromaterials Curation Facility at NASA Johnson Space Center. The name OSIRIS-REx embodies the mission objectives (1) Origins: Return and analyze a sample of a carbonaceous asteroid, (2) Spectral Interpretation: Provide ground-truth for remote observation of asteroids, (3) Resource Identification: Determine the mineral and chemical makeup of a near-Earth asteroid (4) Security: Measure the non-gravitational that changes asteroidal orbits and (5) Regolith Explorer: Determine the properties of the material covering an asteroid surface. Asteroid Bennu may preserve remnants of stardust, interstellar materials and the first solids to form in the Solar System and the molecular precursors to the origin of life and the Earth's oceans. Bennu is a potentially hazardous asteroid, with an approximately 1 in 2700 chance of impacting the Earth late in the 22nd century. OSIRIS-REx collects from Bennu will help formulate the types of operations and identify mission activities that astronauts will perform during their expeditions. Such information is crucial in preparing for humanity's next steps beyond low Earthy orbit and on to deep space destinations.

V-type candidates and Vesta family asteroids in the Moving Objects VISTA (MOVIS) catalogue

NASA Astrophysics Data System (ADS)

Licandro, J.; Popescu, M.; Morate, D.; de León, J.

2017-04-01

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.

Looking into the evolution of granular asteroids in the Solar System

NASA Astrophysics Data System (ADS)

Sánchez, Paul; Scheeres, Daniel; Hirabayashi, Masatoshi; Tardivel, Simon

2017-06-01

By now it has been accepted that most of the small asteroids in the Solar System are granular aggregates kept together by gravitational and possibly, cohesive forces. These aggregates can form, deform and disrupt over millennia subjected to different internal and external factors that would ultimately determine how they evolve over time. Parameters such as porosity, cohesive and tensile strength, angles of friction, particle size distributions, stress states, heterogeneity and yield criteria among others, determine how these granular systems will react when subjected to different, changing, external factors. These external factors include solar photon momentum, gravitational tides, micro- and macro-impacts and are believed to have produced and shaped the current asteroid population. In our research we use a combination of Soil Mechanics theory, Soft-Sphere Discrete Element Method (SSDEM) Simulations and Orbital Mechanics in order to understand how simulated, homogeneous and heterogeneous, ellipsoidal and spherical gravitational aggregates, a crude but useful representation of an asteroid, evolve when rotated to the point of disruption. Then, we compare our results to the shapes of observed asteroids as well as to the disruption patterns of a few active asteroids. Our results lead us to believe that the different shapes of observed asteroids as well as their unique disruption patterns could give us clues about their internal structure, strength and geophysical properties in general.

Escape of asteroids from the Hecuba gap

NASA Astrophysics Data System (ADS)

Michtchenko, T.; Ferraz-Mello, S.

1997-12-01

The dynamics of the 2/1 mean-motion asteroidal resonance with Jupiter is studied by numerical integration of the equations of motion of the Sun-Jupiter-Saturn-asteroid system. The measurement of the fundamental asteroidal frequencies by means of Fourier and wavelet analyses allows us to construct the web of the secular, secondary and Kozai resonances inside the 2/1- resonance boundaries. The structure of the phase space of the 2/1 resonance is discussed with emphasis on the acting depletion mechanisms due to presence of these inner resonances. Special attention is paid to the study of the middle-eccentricity depleted region. The importance of the great inequality of the Jupiter-Saturn system in the acceleration of the diffusion processes in this region is pointed out. The existence of a group of asteroids like (3789) Zhongguo, inside the 2/1 resonance, is also discussed.

Asteroid Satellites

NASA Astrophysics Data System (ADS)

Merline, W. J.

2001-11-01

Discovery and study of small satellites of asteroids or double asteroids can yield valuable information about the intrinsic properties of asteroids themselves and about their history and evolution. Determination of the orbits of these moons can provide precise masses of the primaries, and hence reliable estimates of the fundamental property of bulk density. This reveals much about the composition and structure of the primary and will allow us to make comparisons between, for example, asteroid taxonomic type and our inventory of meteorites. The nature and prevalence of these systems will also give clues as to the collisional environment in which they formed, and have further implications for the role of collisions in shaping our solar system. A decade ago, binary asteroids were more of a theoretical curiosity. In 1993, the Galileo spacecraft allowed the first undeniable detection of an asteroid moon, with the discovery of Dactyl, a small moon of Ida. Since that time, and particularly in the last year, the number of known binaries has risen dramatically. Previously odd-shaped and lobate near-Earth asteroids, observed by radar, have given way to signatures indicating, almost certainly, that at least four NEAs are binary systems. The tell-tale lightcurves of several other NEAs reveal a high likelihood of being double. Indications are that among the NEAs, there may be a binary frequency of several tens of percent. Among the main-belt asteroids, we now know of 6 confirmed binary systems, although their overall frequency is likely to be low, perhaps a few percent. The detections have largely come about because of significant advances in adaptive optics systems on large telescopes, which can now reduce the blurring of the Earth's atmosphere to compete with the spatial resolution of space-based imaging (which itself, via HST, is now contributing valuable observations). Most of these binary systems have similarities, but there are important exceptions. Searches among other dynamical populations such as the Trojans and KBOs are also proving fruitful. Similarities and differences among the detected systems are thus revealing important clues about the possible formation mechanisms. There are several theories seeking to explain the origin of these binary systems, all of them involving collisions of one type or another, either physical or gravitational. It is likely that several of the mechanisms will be required to explain the observations. Now that we have reliable techniques for detection, we have been rewarded with many examples of systems for study. This has in turn spurred new theoretical thinking and numerical simulations, the techniques for which have also improved substantially in recent years.

A Ground Systems Template for Remote Sensing Systems

NASA Astrophysics Data System (ADS)

McClanahan, Timothy P.; Trombka, Jacob I.; Floyd, Samuel R.; Truskowski, Walter; Starr, Richard D.; Clark, Pamela E.; Evans, Larry G.

2002-10-01

Spaceborne remote sensing using gamma and X-ray spectrometers requires particular attention to the design and development of reliable systems. These systems must ensure the scientific requirements of the mission within the challenging technical constraints of operating instrumentation in space. The Near Earth Asteroid Rendezvous (NEAR) spacecraft included X-ray and gamma-ray spectrometers (XGRS), whose mission was to map the elemental chemistry of the 433 Eros asteroid. A remote sensing system template, similar to a blackboard systems approach used in artificial intelligence, was identified in which the spacecraft, instrument, and ground system was designed and developed to monitor and adapt to evolving mission requirements in a complicated operational setting. Systems were developed for ground tracking of instrument calibration, instrument health, data quality, orbital geometry, solar flux as well as models of the asteroid's surface characteristics, requiring an intensive human effort. In the future, missions such as the Autonomous Nano-Technology Swarm (ANTS) program will have to rely heavily on automation to collectively encounter and sample asteroids in the outer asteroid belt. Using similar instrumentation, ANTS will require information similar to data collected by the NEAR X-ray/Gamma-Ray Spectrometer (XGRS) ground system for science and operations management. The NEAR XGRS systems will be studied to identify the equivalent subsystems that may be automated for ANTS. The effort will also investigate the possibility of applying blackboard style approaches to automated decision making required for ANTS.

Compositional study of asteroids in the Erigone collisional family using visible spectroscopy at the 10.4m GTC

NASA Astrophysics Data System (ADS)

Morate, David; de León, Julia; De Prá, Mário; Licandro, Javier; Cabrera-Lavers, Antonio; Campins, Humberto; Pinilla-Alonso, Noemí; Alí-Lagoa, Víctor

2015-11-01

Asteroid families are formed by the fragments produced by the disruption of a common parent body (Bendjoya & Zappalà 2002). Primitive asteroids in the solar system are believed to have undergone less thermal processing than the S-complex asteroids. Thus, study of primitive asteroid families provides information about the solar system formation period. The Erigone collisional family, together with other three families (Polana, Clarissa and Sulamitis), are believed to be the origin of the two primitive Near-Earth asteroids that are the main targets of the NASA’s OSIRIS-REx ((101955) Bennu) and JAXA’s Hayabusa 2 ((162173) 1999 JU3) missions (Campins et al. 2010; Campins et al. 2013; Lauretta et al. 2010; Tsuda et al. 2013). These spacecrafts will visit the asteroids, and a sample of their surface material will be returned to Earth. Understanding of the families that are considered potential sources will enhance the scientific return of the missions. The main goal of the work presented here is to characterize the Erigone collisional family. Asteroid (163) Erigone has been classified as a primitive object (Bus 1999; Bus & Binzel 2002), and we expect the members of this family to be consistent with the spectral type of the parent body. We have obtained visible spectra (0.5-0.9 μm) for 101 members of the Erigone family, using the OSIRIS instrument at the 10.4m Gran Telescopio Canarias. We performed a taxonomical classification of these asteroids, finding that the number of primitive objects in our sample is in agreement with the hypothesis of a common parent body. In addition, we have found a significant fraction of asteroids in our sample that present evidences of aqueous alteration. Study of aqueous alterations is important, as it can give information on the heating processes of the early Solar System, and for the associated astrobiological implications (it has been suggested that the Earth’s present water supply was brought here by asteroids, instead of comets, in opposition to previous explanations (Morbidelli et al. 2000).

Control of asteroid retrieval trajectories to libration point orbits

NASA Astrophysics Data System (ADS)

Ceriotti, Matteo; Sanchez, Joan Pau

2016-09-01

The fascinating idea of shepherding asteroids for science and resource utilization is being considered as a credible concept in a not too distant future. Past studies identified asteroids which could be efficiently injected into manifolds which wind onto periodic orbits around collinear Lagrangian points of the Sun-Earth system. However, the trajectories are unstable, and errors in the capture maneuver would lead to complete mission failure, with potential danger of collision with the Earth, if uncontrolled. This paper investigates the controllability of some asteroids along the transfers and the periodic orbits, assuming the use of a solar-electric low-thrust system shepherding the asteroid. Firstly, an analytical approach is introduced to estimate the stability of the trajectories from a dynamical point of view; then, a numerical control scheme based on a linear quadratic regulator is proposed, where the gains are optimized for each trajectory through a genetic algorithm. A stochastic simulation with a Monte Carlo approach is used to account for different perturbed initial conditions and the epistemic uncertainty on the asteroid mass. Results show that only a small subset of the considered combinations of trajectories/asteroids are reliably controllable, and therefore controllability must be taken into account in the selection of potential targets.

BAOBAB (Big And Outrageously Bold Asteroid Belt) Project

NASA Technical Reports Server (NTRS)

Mcfadden, L. A.; Thomas, C. A; Englander, J. A.; Ruesch, O.; Hosseini, S.; Goossens, S. J.; Mazarico, E. M.; Schmerr, N.

2017-01-01

One of the intriguing results of NASA's Dawn mission is the composition and structure of the Main Asteroid Belt's only known dwarf planet, Ceres [1]. It has a top layer of dehydrated clays and salts [2] and an icy-rocky mantle [3,4]. It is widely known that the asteroid belt failed to accrete as a planet by resonances between the Sun and Jupiter. About 20-30 asteroids >100 km diameter are probably differentiated protoplanets [5]. 1) how many more and which ones are fragments of protoplanets? 2) How many and which ones are primordial rubble piles left over from condensation of the solar nebula? 3) How would we go about gaining better and more complete characterization of the mass, interior structure and composition of the Main Belt asteroid population? 4) What is the relationship between asteroids and ocean worlds? Bulk parameters such as the mass, density, and porosity, are important to characterize the structure of any celestial body, and for asteroids in particular, they can shed light on the conditions in the early solar system. Asteroid density estimates exist but currently they are often based on assumed properties of taxonomic classes, or through astronomical survey data where interactions with asteroids are weak at best resulting in large measurement uncertainty. We only have direct density estimates from spacecraft encounters for a few asteroids at this time. Knowledge of the asteroids is significant not only to understand their role in solar system workings, but also to assess their potential as space resources, as impact hazards on Earth, or even as harboring life forms. And for the distant future, we want to know if the idea put forth in a contest sponsored by Physics Today, to surface the asteroids into highly reflecting, polished surfaces and use them as a massively segmented mirror for astrophysical exploration [6], is feasible.

Investigation of the interior of primordial asteroids and the origin of the Earth's water: The INSIDER space mission

NASA Astrophysics Data System (ADS)

Vernazza, P.; Lamy, P.

2014-07-01

Today's asteroid belt may not only be populated by objects that formed in situ, typically between 2.2 and 3.3 au, but also by bodies that formed over a very large range of heliocentric distances. It is currently proposed that both the early (<5 Myrs after Solar System formation) and late (>700 Myrs after Solar System formation) dynamical evolution of the Solar System was governed by giant planet migrations that led to the insertion of inner (1--3 au) as well as outer (4--13 au) small bodies in the asteroid belt. Taken altogether, the current dynamical models are able to explain many striking features of the asteroid belt including i) its incredible compositional diversity deduced mainly from spectroscopic observations and meteorites measurements, and ii) the evidence of radial mixing experienced by the various asteroid classes (e.g., S-, C-types) after their formation. In a broad stroke, the idea that the asteroid belt is a condensed version of the primordial Solar System is progressively emerging. The asteroid belt therefore presents the double advantage of being easily accessible and of offering crucial tests for the formation models of the Solar System by exploring the building blocks predicted by models of i) the telluric planets, ii) the giant planet cores, iii) the giant planets' satellites, and iv) outer small bodies such TNOs and comets. It also appears as an ideal place to search for the origin of Earth's water. Up to now, only a few asteroid classes (e.g., several S-types) have been visited by spacecraft and the focus of these in situ measurements has been mainly to give a geological context to ground based observations as well as strengthen/validate their interpretation. Most of the tantalizing discoveries of asteroid missions have been realized via images of the objects surfaces. Time has come for asteroid space science to reach a new milestone by extending the reconnaissance of the Belt's diversity and addressing new science questions. The scientific objectives of the INSIDER mission, to be proposed in response to the 2014 ESA call for an M-class mission, require the exploration of diverse primordial asteroids --- possibly the smallest surviving protoplanets of our Solar System --- in order to constrain the earliest stages of planetesimal formation thus avoiding the effect of destructive collisions, which produce extensively processed rubble piles. Our science objectives that justify in situ measurements in the context of an M-class mission and that are expected to lead to significant breakthroughs include: - The exploration of the diversity of the asteroid belt - The first investigation of the internal structure of asteroids - The origin of water on Earth The proposed mission scenario consists in i) successive rendez-vous followed by orbit insertion of two and possibly three large (D>100 km) objects, ii) one or two small landing modules (MASCOT type) to perform cosmochemical measurements (D/H ratio, O isotopes). The potential targets would include 24 Themis and 10 Hygiea. Meeting our science objectives requires instruments (such as radar, seismometers to be dropped to the surface, magnetometer, high resolution laser-desorption-ionization mass spectrometer to analyse the surface samples) not flown so far during past asteroids missions along with the traditional powerhouses, such as cameras and spectrometers.

Overview of Mission Design for NASA Asteroid Redirect Robotic Mission Concept

NASA Technical Reports Server (NTRS)

Strange, Nathan; Landau, Damon; McElrath, Timothy; Lantoine, Gregory; Lam, Try; McGuire, Melissa; Burke, Laura; Martini, Michael; Dankanich, John

2013-01-01

Part of NASA's new asteroid initiative would be a robotic mission to capture a roughly four to ten meter asteroid and redirect its orbit to place it in translunar space. Once in a stable storage orbit at the Moon, astronauts would then visit the asteroid for science investigations, to test in space resource extraction, and to develop experience with human deep space missions. This paper discusses the mission design techniques that would enable the redirection of a 100-1000 metric ton asteroid into lunar orbit with a 40-50 kW Solar Electric Propulsion (SEP) system.

New infrared spectral data for 27 asteroids: An investigation of meteorite- asteroid relationships by using the modified Gaussian model

NASA Astrophysics Data System (ADS)

Gietzen, Katherine M.

2009-09-01

Asteroids provide unique insights into the origin and early history of the solar system. Since asteroids are considered to be fairly pristine, studying them provides opportunities to learn more about the primordial solar system, its materials, processes and history. Since the discovery in 1801 of the first asteroid, Ceres, during the era when everyone was searching for the "missing planet", astronomers have been trying to understand what they are, where they came from, why they exist and what they can tell us about how our solar system formed and evolved. Within the asteroid population are a number of sub-populations, the primary division is due to the locations of the asteroids. There are the Main Belt Asteroid (MBA) population that resides between the orbits of Mars and Jupiter (1.8 - 3.5 AU) and the Near-Earth Asteroid (NEA) population whose orbits have an aphelion <= 1.3 AU. Within both the MBA and NEA populations are further subdivisions (taxonomic classes) based on physical properties of the asteroids such as albedo, spectral curve and probable composition. There have been a number of taxonomic classification schemes, the most current iteration splits the asteroids into three complexes (C, S, and X) that combined are comprised of twenty-six distinct taxonomic classes. Since the lifetimes of the NEAs are short (10 6 - 10 7 yrs), it is thought that the NEA population is and continues to be populated by the MBA population through various mechanisms like resonances and thermal forces. We have conducted a statistical comparison of the two populations as a whole, by complexes and individual taxonomic classes and found significant differences as well as similarities. On the surface, it appears that the NEA population is not representative of the MBA population. There are voids and relatively small numbers in taxonomic classes that exist in the NEA when compared to the MBA population and there are some important similarities. There are, however, biases that this analysis does not address that may explain our findings. The asteroid taxonomy classification schemas are based on visible wavelength spectra. There are ~2500 classified asteroids of which only a very small percentage have spectra in the infrared wavelength ranges. Here we demonstrate, using asteroid 1989 ML, the need for more asteroid spectra in the near-infrared wavelength range which contains much compositional information. We show that in the visible wavelengths spectra of several meteorites of very different types match the spectrum of 1989 ML. Finally, we examine twenty-seven S and possible S Complex asteroid spectra. We find that most contain pyroxenes in the monoclinic form (clinopyroxene). Clinopyroxenes can contain calcium; however, there are some that do not. The cases of Ca-free clinopyroxenes are rare on Earth, but are readily found in the type 3 unequilibrated ordinary chondrites. Analyses of the asteroids and ordinary chondrites were conducted using the Modified Gaussian Model (MGM) and the Band Area Ratio. We also examined two terrestrial Ca-free clinopyroxenes using the MGM. From our results we conclude that the surfaces of S Complex asteroids are consistent with the type 3 unequilibrated ordinary chondrites.

Observations of Spacecraft Targets, Unusual Asteroids, and Targets of Opportunity

NASA Technical Reports Server (NTRS)

Tholen, David J.

1998-01-01

Obtain physical and astrometric observations of: (1) spacecraft targets to support mission operations; (2) known asteroids with unusual orbits to help determine their origin; and (3) newly discovered minor planets (including both asteroids and comets) that represent a particular opportunity to add significant new knowledge of the Solar System.

Overview of the Mission Design Reference Trajectory for NASA's Asteroid Redirect Robotic Mission

NASA Technical Reports Server (NTRS)

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.

2017-01-01

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.

Constraints on the Detection of the Solar Nebula's Oxidation State Through Asteroid Observations

NASA Technical Reports Server (NTRS)

Abell, P. A.; Gaffey, M. J.; Hardersen, P. S.

2005-01-01

Introduction: Asteroids represent the only in situ surviving population of planetesimals from the formation of the inner solar system and therefore include materials from the very earliest stages of solar system formation. Hence, these bodies can provide constraints on the processes and conditions that were present during this epoch and can be used to test current models and theories describing the late solar nebula, the early solar system and subsequent planetary accretion. From detailed knowledge of asteroid mineralogic compositions the probable starting materials, thermal histories, and oxidation states of asteroid parent bodies can be inferred. If such data can be obtained from specific mainbelt source regions, then this information can be used to map out the formation conditions of the late solar nebula within the inner solar system and possibly distinguish any trends in oxidation state that may be present.

A New Equilibrium State for Singly Synchronous Binary Asteroids

NASA Astrophysics Data System (ADS)

Golubov, Oleksiy; Unukovych, Vladyslav; Scheeres, Daniel J.

2018-04-01

The evolution of rotation states of small asteroids is governed by the Yarkovsky–O’Keefe–Radzievskii–Paddack (YORP) effect, nonetheless some asteroids can stop their YORP evolution by attaining a stable equilibrium. The same is true for binary asteroids subjected to the binary YORP (BYORP) effect. Here we discuss a new type of equilibrium that combines these two, which is possible in a singly synchronous binary system. This equilibrium occurs when the normal YORP, the tangential YORP, and the BYORP compensate each other, and tidal torques distribute the angular momentum between the components of the system and dissipate energy. If unperturbed, such a system would remain singly synchronous in perpetuity with constant spin and orbit rates, as the tidal torques dissipate the incoming energy from impinging sunlight at the same rate. The probability of the existence of this kind of equilibrium in a binary system is found to be on the order of a few percent.

1991 Urey Prize Lecture: Physical evolution in the solar system - Present observations as a key to the past

NASA Technical Reports Server (NTRS)

Binzel, Richard P.

1992-01-01

The present evaluation of the use of new observational methods for exploring solar system evolutionary processes gives attention to illustrative cases from the constraining of near-earth asteroid sources and the discovery of main-belt asteroid fragments which indicate Vesta to be a source of basaltic achondrite meteorites. The coupling of observational constraints with numerical models clarifies cratering and collisional evolution for both main-belt and Trojan asteroids.

Dynamics of Populations of Planetary Systems (IAU C197)

NASA Astrophysics Data System (ADS)

Knezevic, Zoran; Milani, Andrea

2005-05-01

1. Resonances and stability of extra-solar planetary systems C. Beaugé, N. Callegari, S. Ferraz-Mello and T. A. Michtchenko; 2. Formation, migration, and stability of extrasolar planetary systems Fred C. Adams; 3. Dynamical evolution of extrasolar planetary systems Ji-Lin Zhou and Yi-Sui Sun; 4. Dynamics of planetesimals: the role of two-body relaxation Eiichiro Kokubo; 5. Fitting orbits Andrzej J. Maciejewski, Krzysztof Gozdziewski and Szymon Kozlowski; 6. The secular planetary three body problem revisited Jacques Henrard and Anne-Sophie Libert; 7. Dynamics of extrasolar systems at the 5/2 resonance: application to 47 UMa Dionyssia Psychoyos and John D. Hadjidemetriou; 8. Our solar system as model for exosolar planetary systems Rudolf Dvorak, Áron Süli and Florian Freistetter; 9. Planetary motion in double stars: the influence of the secondary Elke Pilat-Lohinger; 10. Planetary orbits in double stars: influence of the binary's orbital eccentricity Daniel Benest and Robert Gonczi; 11. Astrometric observations of 51 Peg and Gliese 623 at Pulkovo observatory with 65 cm refractor N. A. Shakht; 12. Observations of 61 Cyg at Pulkovo Denis L. Gorshanov, N. A. Shakht, A. A. Kisselev and E. V. Poliakow; 13. Formation of the solar system by instability Evgeny Griv and Michael Gedalin; 14. Behaviour of a two-planetary system on a cosmogonic time-scale Konstantin V. Kholshevnikov and Eduard D. Kuznetsov; 15. Boundaries of the habitable zone: unifying dynamics, astrophysics, and astrobiology Milan M. Cirkovic; 16. Asteroid proper elements: recent computational progress Fernando Roig and Cristian Beaugé; 17. Asteroid family classification from very large catalogues Anne Lemaitre; 18. Non-gravitational perturbations and evolution of the asteroid main belt David Vokrouhlicky, M. Broz and W. F. Bottke, D. Nesvorny and A. Morbidelli; 19. Diffusion in the asteroid belt Harry Varvoglis; 20. Accurate model for the Yarkovsky effect David Capek and David Vokrouhlicky; 21. The population of asteroids in the 2:1 mean motion resonance with Jupiter revised Miroslav Broz, D. Vokrouhlicky, F. Roig, D. Nesvorny, W. F. Bottke and A. Morbidelli; 22. On the reliability of computation of maximum Lyapunov Characteristic Exponents for asteroids Zoran Knezevic and Slobodan Ninkovic; 23. Nekhoroshev stability estimates for different models of the Trojan asteroids Christos Efthymiopoulos; 24. The role of the resonant 'stickiness' in the dynamical evolution of Jupiter family comets A. Alvarez-Canda and F. Roig; 25. Regimes of stability and scaling relations for the removal time in the asteroid belt: a simple kinetic model and numerical tests Mihailo Cubrovic; 26. Virtual asteroids and virtual impactors Andrea Milani; 27. Asteroid population models Alessandro Morbidelli; 28. Linking Very Large Telescope asteroid observations M. Granvik, K. Muinonen, J. Virtanen, M. Delbó, L. Saba, G. De Sanctis, R. Morbidelli, A. Cellino and E. Tedesco; 29. Collision orbits and phase transition for 2004 AS1 at discovery Jenni Virtanen, K. Muinonen, M. Granvik and T. Laakso; 30. The size of collision solutions in orbital elements space G. B. Valsecchi, A. Rossi, A. Milani and S. R. Chesley; 31. Very short arc orbit determination: the case of asteroid 2004 FU162 Steven R. Chesley; 32. Nonlinear impact monitoring: 2-dimensional sampling Giacomo Tommei; 33. Searching for gravity assisted trajectories to accessible near-Earth asteroids Stefan Berinde; 34. KLENOT - Near Earth and other unusual objects observations Michal Kocer, Jana Tichá and M. Tichy; 35. Transport of comets to the Inner Solar System Hans Rickman; 36. Nongravitational Accelerations on Comets Steven R. Chesley and Donald K. Yeomans; 37. Interaction of planetesimals with the giant planets and the shaping of the trans-Neptunian belt Harold F. Levison and Alessandro Morbidelli; 38. Transport of comets to the outer p

Asteroids Search Results in Large Photographic Sky Surveys

NASA Astrophysics Data System (ADS)

Shatokhina, S. V.; Kazantseva, L. V.; Yizhakevych, O. M.; Eglitis, I.; Andruk, V. M.

Photographic observations of XX century contained numerous and varied information about all objects and events of the Universe fixed on plates. The original and interesting observations of small bodies of the Solar system in previous years can be selected and used for various scientific tasks. Existing databases and online services can help make such selection easily and quickly. The observations of chronologically earlier ppositions, photometric evaluation of brightness for long periods of time allow refining the orbits of asteroids and identifying various non-stationaries. Photographic observations of Northern Sky Survey project and observations of clusters in UBVR bands were used for global search for small bodies of Solar system. Total we founded 2486 positions of asteroids and 13 positions of comets. All positions were compared with ephemeris. It was found that 80 positions of asteroids have a moment of observation preceding their discovery, and 19 of them are chronologically the earliest observations of these asteroids in the world.

Instabilities in the Sun-Jupiter-Asteroid three body problem

NASA Astrophysics Data System (ADS)

Urschel, John C.; Galante, Joseph R.

2013-03-01

We consider dynamics of a Sun-Jupiter-Asteroid system, and, under some simplifying assumptions, show the existence of instabilities in the motions of an asteroid. In particular, we show that an asteroid whose initial orbit is far from the orbit of Mars can be gradually perturbed into one that crosses Mars' orbit. Properly formulated, the motion of the asteroid can be described as a Hamiltonian system with two degrees of freedom, with the dynamics restricted to a "large" open region of the phase space reduced to an exact area preserving map. Instabilities arise in regions where the map has no invariant curves. The method of MacKay and Percival is used to explicitly rule out the existence of these curves, and results of Mather abstractly guarantee the existence of diffusing orbits. We emphasize that finding such diffusing orbits numerically is quite difficult, and is outside the scope of this paper.

Tidal stress and failure in the moon of binary asteroid systems: Application to asteroid (65803) Didymos

NASA Astrophysics Data System (ADS)

Sophal Pou, Laurent; Garcia, Raphael F.; Mimoun, David; Murdoch, Naomi; Karatekin, Ozgur

2017-04-01

Rocky remnants left over from the early formation of the Solar System, asteroids are a target of choice for planetary science since much about the history of planetary formation and small body evolution processes can be learnt by studying them. Here we consider the case of the binary asteroid (65803) Didymos, the target of several mission proposals e.g., AIM [1] and DART [2]. A mission to Didymos would be a great opportunity for in-situ geophysical investigation, providing information on the surface and interior of asteroids. Such studies would improve our knowledge of binary asteroid formation and subsequent evolution of asteroids, thus of the history of the Solar System. As Didymos is a binary asteroid [3] with the main 800-meter diameter asteroid named Didymain and a 150-meter sized moon named Didymoon, both are subject to tidal stress. Recent investigations suggest that Didymoon is tidally locked and moves in a retrograde motion around Didymain along an elliptic orbit with a 0.03 eccentricity at most. In the case of an eccentric orbit, the tidal stress varies periodically and may be strong enough to cause tidal quakes on Didymoon at some points of the orbit. For this study, we modelled Didymoon as a spherical, layered body with different internal structures: a homogeneous model, and two models with a 1-meter and 10-meter regolith layer on top of a stronger internal core. Simulations show that, for a cohesionless body with an internal friction angle of 30°, tidal stress is strong enough to cause failure at the surface of Didymoon. A maximal stress is reached around the poles and for a mean anomaly of 90°. These results would mean that if tidal quakes occur on Didymoon, then they are likely to happen at these locations. An extension of these results to an ellipsoidal model of Didymoon is also presented for comparison with the spherical case and for application to other bodies. [1]: P. Michel et al., Science case for the asteroid impact mission (aim): A component of the asteroid impact and deflection assessment (aida) mission, Advances in Space Research 57 (12) (2016) 2529 - 2547. doi:http://dx.doi.org/10.1016/j.asr.2016.03.031. [2]: A. F. Cheng et al., Asteroid Impact & Deflection Assessment mission: Kinetic impactor, Planetary and Space Science 121 (2016) 27-35. doi:10.1016/j.pss.2015.12.004. [3]:"AIM-A Team", ASTEROID IMPACT MISSION: DIDYMOS REFERENCE MODEL v10, ESA document reference: AD3-AIMA.

Two cubesat mission to study the Didymos asteroid system

NASA Astrophysics Data System (ADS)

Wahlund, J.-E.; Vinterhav, E.; Trigo-Rodríguez, J. M.; Hallmann, M.; Barabash, S.; Ivchenko, N.

2015-10-01

Among the growing interest about asteroid impact hazard mitigation in our community the Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to use a kinetic impactor to demonstrate its capability as reliable deflection system [1]. As a part of the AIDA mission, we have proposed a set of two three-axis stabilized 3U CubeSats (with up to 5 science sensors) to simultaneously rendezvous at close range (<500m) with both the primary and the secondary component of the Didymos asteroid system. The CubeSats will be hosted on the ESA component of the AIDA mission, the monitoring satellite AIM (Asteroid Impact Mission). The CubeSats will characterise the magnetization, the main bulk chemical composition and presence of volatiles as well as do superresolution surface imaging of the Didymos components. The CubeSats will also support the plume characterisation resulting from the DART impact (Double Asteroid Redirection Test, a NASA component of the AIDA mission) at much closer range than the AIM main spacecraft, and provide imaging, composition, and temperature of the plume material. At end of the mission, the two CubeSats can optionally land on one of the asteroids for continued science operation. The science sensors consist of a dual fluxgate magnetometer (MAG), one miniaturized volatile composition analyser (VCA), a narrow angle camera (NAC) and a Video Emission Spectrometer (VES) with a diffraction grating for allowing a sequential chemical study of the emission spectra associated with the impact flare and the expanding plume. Consequently, the different envisioned instruments onboard the CubeSats can provide significant insight into the complex response of asteroid materials during impacts that has been theoretically studied using different techniques [2]. The two CubeSats will remain stowed in CubeSat dispensers aboard the main AIM spacecraft. They will be deployed and commissioned before the AIM impactor reaches the secondary and record the impact event from a closer vantage point than the main spacecraft. The two CubeSats are equipped with relative navigation systems capable of estimating the spacecraft position relative to the asteroids and propulsion system that allow them to operate close to the asteroid bodies. The two CubeSats will rely on mapping data relayed via the AIM main spacecraft but operate autonomously and individually based on schedules and navigation maps uploaded from ground. AIDA's target is the binary Apollo asteroid 65803 Didymos that is also catalogued as Potentially Hazardous Asteroid (PHA) because it experiences close approaches to Earth. Didymos' primary has a diameter of ˜800 meters and the secondary is ˜150 m across. Both bodies are separated about 1.1 km [3]. The rotation period and asymmetry of the secondary object is unknown, and it might be tidally locked to the larger primary body. At least the primary body is expected to be associated with ordinary chondrite material, consisting mostly of silicates, and metal, but the earlier made Xk classification suggested a rubble-pile type with large amount of volatile content. The secondary companion spectral class is unknown, but the total mass of the system suggests that the secondary companion could be of similar class. Detailed empirical information on the physical properties of the Didymos asteroid system, in particular the magnetic field, the (mineralogical) surface composition, the internal composition via the bulk density, the ages of surface units through crater counts and other morphological surface features is valuable in order to make progress in the asteroid field of science. Furthermore, the periodic effect of such a close dynamic system in the presence and temporal displacement of the surface regolith is EPSC Abstracts Vol. 10, EPSC2015-698, 2015 European Planetary Science Congress 2015 c Author(s) 2015 EPSC European Planetary Science Congress unknown, and could be followed using close-up video systems provided by the CubeSats. In conclusion, the proposed two CubeSats as part of the AIDA mission can therefore contribute significantly, since they can monitor the Didymos asteroid components at a very close range around hundred meters, and at the same time monitor in-situ an impact plume when it is created.

Asteroid exploration and utilization

NASA Technical Reports Server (NTRS)

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

1992-01-01

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.

Compositional Variation in Large-Diameter Low-Albedo asteroids

NASA Astrophysics Data System (ADS)

Vilas, F.; Jarvis, K. S.; Thibault, C. A.; Sawyer, S. R.

2000-12-01

Age dating of meteorites indicates that the Solar System was subjected to a major heating event 4.5 Gyr ago. 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, 124) have shown using ECAS photometry that this compositional difference exists. The larger diameter group should be individually homogenous, with spectral differences showing the combined effects of a primordial compositional gradient in the asteroid belt with thermal metamorphism. We address the significance of 36 rotationally-resolved spectra of larger-diameter low-albedo asteroids of the C class (and subclasses B, F, G) and P class in the visible and Near-IR spectral regions. This work was supported by the NASA Planetary Astronomy program.

On the Origin of Chaos in the Asteroid Belt

NASA Technical Reports Server (NTRS)

Murray, N.; Holman, M.; Potter, M.

1998-01-01

We consider the effect of gravitational perturbations from Jupiter on the dynamics of asteroids, when Jupiter is itself perturbed by Saturn. The presence of Saturn introduces a number of additional frequencies into Jupiters orbit. These frequencies in turn produce chaos in narrow regions on either side of the chaotic zones associated with the mean motion resonances between the asteroids and Jupiter. The resonant arguments of these three-body resonances contain the longitudes of Jupiter and the asteroid together with either the secular frequency 9-6, or the longitude of Saturn. Resonances involving the longitude of Saturn are analogs of the Laplace resonance in the Jovian satellite system. We show that many three-body resonances involving the longitude of Saturn are chaotic. We give simple expressions for the width of the chaotic region and the associated Lyapunov time. In some cases the chaos can produce a diffusive growth in the 4 eccentricity of the asteroid that leads to ejection of the asteroid on times shorter than the age of the solar system. We give simple estimates for the diffusion time. Finally, we present the results of numerical integrations testing the theory.

LONG-TERM STABLE EQUILIBRIA FOR SYNCHRONOUS BINARY ASTEROIDS

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

Jacobson, Seth A.; Scheeres, Daniel J.

Synchronous binary asteroids may exist in a long-term stable equilibrium, where the opposing torques from mutual body tides and the binary YORP (BYORP) effect cancel. Interior of this equilibrium, mutual body tides are stronger than the BYORP effect and the mutual orbit semimajor axis expands to the equilibrium; outside of the equilibrium, the BYORP effect dominates the evolution and the system semimajor axis will contract to the equilibrium. If the observed population of small (0.1-10 km diameter) synchronous binaries are in static configurations that are no longer evolving, then this would be confirmed by a null result in the observationalmore » tests for the BYORP effect. The confirmed existence of this equilibrium combined with a shape model of the secondary of the system enables the direct study of asteroid geophysics through the tidal theory. The observed synchronous asteroid population cannot exist in this equilibrium if described by the canonical 'monolithic' geophysical model. The 'rubble pile' geophysical model proposed by Goldreich and Sari is sufficient, however it predicts a tidal Love number directly proportional to the radius of the asteroid, while the best fit to the data predicts a tidal Love number inversely proportional to the radius. This deviation from the canonical and Goldreich and Sari models motivates future study of asteroid geophysics. Ongoing BYORP detection campaigns will determine whether these systems are in an equilibrium, and future determination of secondary shapes will allow direct determination of asteroid geophysical parameters.« less

Negative Searches for Evidence of Aqueous Alteration on Asteroid Surfaces

NASA Technical Reports Server (NTRS)

Vilas, F.

2005-01-01

Small bodies in the Solar System preserve evidence of the processes occurring during early Solar System formation, unlike the larger planets that undergo continuous churning of their surfaces. We study these bodies to understand what processes affected different stages of Solar System formation. The action of aqueous alteration (the alteration of material by the interaction of that material with liquid formed by the melting of incorporated ice) of near-subsurface material has been inferred to occur on many asteroids based on the spectrophotometric evidence of phyllosilicates and iron alteration minerals. The definitive indication of aqueous alteration is the 3.0- micron absorption feature attributed to structural hydroxyl (OH) and interlayer and adsorbed water (H2O) in phyllosilicates (clays) (hereafter water of hydration). A weak absorption feature centered near 0.7 microns attributed to an Fe (2+) right arrow Fe (3+) charge transfer transition in oxidized iron in phyllosilicates has been observed in the reflectance spectra and photometry of approximately 50% of the main-belt C-class asteroids. An approximately 85% correlation between this 0.7- micron feature and the 3.0- micron water of hydration absorption feature was found among the low-albedo asteroids. The feature is usually centered near 0.68 microns in asteroid spectra, and ranges in wavelength from approximately 0.57 to 0.83 microns. Serendipitously, three of the Eight Color Asteroid Survey filters the v (0.550 microns), w (0.701 microns), and x (0.853 microns)-bracket this feature well, and can be used to determine the presence of this feature in the reflectance properties of an asteroid, and probe the aqueous alteration history of larger samples of asteroid data. Two efforts to search for evidence of aqueous alteration based on the presence of this 0.7- micron absorption feature are presented here.

Multiple Asteroid Systems: Dimensions and Thermal Properties from Spitzer Space Telescope and Ground-based Observations

NASA Technical Reports Server (NTRS)

Marchis, F.; Enriquez, J. E.; Emery, J. P.; Mueller, M.; Baek, M.; Pollock, J.; Assafin, M.; Matins, R. Vieira; Berthier, J.; Vachier, F.;

Band of Rubble

NASA Technical Reports Server (NTRS)

2005-01-01

This artist's animation illustrates a massive asteroid belt in orbit around a star the same age and size as our Sun. Evidence for this possible belt was discovered by NASA's Spitzer Space Telescope when it spotted warm dust around the star, presumably from asteroids smashing together.

The view starts from outside the belt, where planets like the one shown here might possibly reside, then moves into to the dusty belt itself. A collision between two asteroids is depicted near the end of the movie. Collisions like this replenish the dust in the asteroid belt, making it detectable to Spitzer.

The alien belt circles a faint, nearby star called HD 69830 located 41 light-years away in the constellation Puppis. Compared to our own solar system's asteroid belt, this one is larger and closer to its star - it is 25 times as massive, and lies just inside an orbit equivalent to that of Venus. Our asteroid belt circles between the orbits of Mars and Jupiter.

Because Jupiter acts as an outer wall to our asteroid belt, shepherding its debris into a series of bands, it is possible that an unseen planet is likewise marshalling this belt's rubble. Previous observations using the radial velocity technique did not locate any large gas giant planets, indicating that any planets present in this system would have to be the size of Saturn or smaller.

Asteroids are chunks of rock from 'failed' planets, which never managed to coalesce into full-sized planets. Asteroid belts can be thought of as construction sites that accompany the building of rocky planets.

Analyzing Serendipitous Asteroid Observations in Imaging Data using PHOTOMETRYPIPELINE

NASA Astrophysics Data System (ADS)

Ard, Christopher; Mommert, Michael; Trilling, David E.

2016-10-01

Asteroids are nearly ubiquitous in the night sky, making them present in the majority of imaging data taken every night. Serendipitous asteroid observations represent a treasure trove to Solar System researchers: accurate positional measurements of asteroids provide important constraints on their sometimes highly uncertain orbits, whereas calibrated photometric measurements can be used to establish rotational periods, intrinsic colors, or photometric phase curves.We present an add-on to the PHOTOMETRYPIPELINE (PP, github.com/mommermi/photometrypipeline, see Poster presentation 123.42) that identifies asteroids that have been observed serendipitously and extracts astrometry and calibrated photometry for these objects. PP is an open-source Python 2.7 software suite that provides image registration, aperture photometry, photometric calibration, and target identification with only minimal human interaction.Asteroids are identified based on approximate positions that are pre-calculated for a range of dates. Using interpolated coordinates, we identify potential asteroids that might be in the observed field and query their exact positions and positional uncertainties from the JPL Horizons system. The method results in robust astrometry and calibrated photometry for all asteroids in the field as a function of time. Our measurements will supplement existing photometric databases of asteroids and improve their orbits.We present first results using this procedure based on imaging data from the Vatican Advanced Technology Telescope.This work was done in the framework of NAU's REU summer program that is supported by NSF grant AST-1461200. PP was developed in the framework of the "Mission Accessible Near-Earth Object Survey" (MANOS) and is supported by NASA SSO grants NNX15AE90G and NNX14AN82G.

Oxygen isotope variation in stony-iron meteorites.

PubMed

Greenwood, R C; Franchi, I A; Jambon, A; Barrat, J A; Burbine, T H

2006-09-22

Asteroidal material, delivered to Earth as meteorites, preserves a record of the earliest stages of planetary formation. High-precision oxygen isotope analyses for the two major groups of stony-iron meteorites (main-group pallasites and mesosiderites) demonstrate that each group is from a distinct asteroidal source. Mesosiderites are isotopically identical to the howardite-eucrite-diogenite clan and, like them, are probably derived from the asteroid 4 Vesta. Main-group pallasites represent intermixed core-mantle material from a single disrupted asteroid and have no known equivalents among the basaltic meteorites. The stony-iron meteorites demonstrate that intense asteroidal deformation accompanied planetary accretion in the early Solar System.

Methods of determination of periods in the motion of asteroids

NASA Astrophysics Data System (ADS)

Bien, R.; Schubart, J.

Numerical techniques for the analysis of fundamental periods in asteroidal motion are evaluated. The specific techniques evaluated were: the periodogram analysis procedure of Wundt (1980); Stumpff's (1937) system of algebraic transformations; and Labrouste's procedure. It is shown that the Labrouste procedure permitted sufficient isolation of single oscillations from the quasi-periodic process of asteroidal motion. The procedure was applied to the analysis of resonance in the motion of Trojan-type and Hilda-type asteroids, and some preliminary results are discussed.

Secular Resonances During Main-Sequence and Post-Main-Sequence Planetary System Dynamics

NASA Astrophysics Data System (ADS)

Smallwood, Jeremy L.

We investigate gravitational perturbations of an asteroid belt by secular resonances. We ap- ply analytic and numerical models to main-sequence and post-main-sequence planetary systems. First, we investigate how the asteroid impact rate on the Earth is affected by the architecture of the planetary system. We find that the nu6 resonance plays an important role in the asteroid collision rate with the Earth. Compared to exoplanetary systems, the solar system is somewhat special in its lack of a super-Earth mass planet in the inner solar system. We therefore consider the effects of the presence of a super-Earth in the terrestrial planet region. We find a significant effect for super-Earths with a mass of around 10 M_{Earth} and a separation greater than about 0.7 AU. These results have implications for the habitability of exoplanetary systems. Secondly, we model white dwarf pollution by asteroids from secular resonances. In the past few decades, observations have revealed signatures of metals polluting the atmospheres of white dwarfs that require a continu- ous accretion of asteroids. We show that secular resonances driven by two outer companions can provide a source of pollution if an inner terrestrial planet is engulfed during the red-giant branch phase. Secular resonances may be a viable mechanism for the pollution of white dwarfs in a variety of exoplanetary system architectures including systems with two giant planets and systems with one giant planet and a binary star companion.

Detailed Pictures of Multiple Asteroid Systems in the Main-Belt

NASA Astrophysics Data System (ADS)

Marchis, F.; Emery, J. P.; Enriquez, J. E.; Descamps, P.; Berthier, J.; Vachier, F.; Durech, J.

2011-12-01

Since their discovery less than 10 years ago, ~200 known multiple asteroid systems have been studied with a combination of observing techniques, including adaptive optics, lightcurve photometry, and mid-infrared spectrophotometry. Those observations show that ~15 large (D>100km) asteroids that are known to possess km-sized satellite(s) (22 Kalliope, 45 Eugenia, 87 Sylvia, 93 Minerva, 216 Kleopatra, ...) share common orbital characteristics, implying a common formation scenario: e.g. catastrophic disruption or ejection after an oblique impact. More than 70 smaller (10-15km) binary asteroid systems have been detected through anomalies in their lightcurves and are believed to have formed by fission due to the YORP effect. By comparison with meteorite analog densities, mid-IR data reveal that these systems have a significant porosity (larger than 30%) implying a rubble-pile interior. We will review these key results and discuss their implications for the interior of asteroids in the light of recent space mission results. Future explorations using new ground-based facilities and space mission concepts will be also discussed. This work is supported by the NSF grant AAG-0807468 and NASA grant NNX11AD62G

OSIRIS-REx Asteroid Sample Return Mission Image Analysis

NASA Astrophysics Data System (ADS)

Chevres Fernandez, Lee Roger; Bos, Brent

2018-01-01

NASA’s Origins Spectral Interpretation Resource Identification Security-Regolith Explorer (OSIRIS-REx) mission constitutes the “first-of-its-kind” project to thoroughly characterize a near-Earth asteroid. The selected asteroid is (101955) 1999 RQ36 (a.k.a. Bennu). The mission launched in September 2016, and the spacecraft will reach its asteroid target in 2018 and return a sample to Earth in 2023. The spacecraft that will travel to, and collect a sample from, Bennu has five integrated instruments from national and international partners. NASA's OSIRIS-REx asteroid sample return mission spacecraft includes the Touch-And-Go Camera System (TAGCAMS) three camera-head instrument. The purpose of TAGCAMS is to provide imagery during the mission to facilitate navigation to the target asteroid, confirm acquisition of the asteroid sample and document asteroid sample stowage. Two of the TAGCAMS cameras, NavCam 1 and NavCam 2, serve as fully redundant navigation cameras to support optical navigation and natural feature tracking. The third TAGCAMS camera, StowCam, provides imagery to assist with and confirm proper stowage of the asteroid sample. Analysis of spacecraft imagery acquired by the TAGCAMS during cruise to the target asteroid Bennu was performed using custom codes developed in MATLAB. Assessment of the TAGCAMS in-flight performance using flight imagery was done to characterize camera performance. One specific area of investigation that was targeted was bad pixel mapping. A recent phase of the mission, known as the Earth Gravity Assist (EGA) maneuver, provided images that were used for the detection and confirmation of “questionable” pixels, possibly under responsive, using image segmentation analysis. Ongoing work on point spread function morphology and camera linearity and responsivity will also be used for calibration purposes and further analysis in preparation for proximity operations around Bennu. Said analyses will provide a broader understanding regarding the functionality of the camera system, which will in turn aid in the fly-down to the asteroid, as it will allow the pick of a suitable landing and sample location.

The Advanced Jovian Asteroid Explorer (AJAX)

NASA Astrophysics Data System (ADS)

Murchie, S. L.; Adams, E. Y.; Mustard, J. F.; Rivkin, A.; Peplowski, P. N.

2015-12-01

The Advanced Jovian Asteroid eXplorer (AJAX) is the first mission to characterize the geology, morphology, geophysical properties, and chemistry of a Trojan asteroid. The Decadal Survey outlined a notional New Frontiers class Trojan asteroid rendezvous mission to conduct geological, elemental composition, mineralogical, and geophysical investigations. AJAX, our Discovery mission proposal, addresses the Decadal Survey science goals by using a focused payload and an innovative mission design. By responding to the most important questions about the Trojan asteroids, AJAX advances our understanding of all of the Solar System. Are these objects a remnant population of the local primordial material from which the outer planets and their satellites formed, or did they originate in the Kuiper Belt? Landed measurements of major and minor elements test hypotheses for the Trojan asteroid origin, revealing the outer Solar System dynamical history. How and when were prebiotic materials delivered to the terrestrial planets? AJAX's landed measurements include C and H concentrations, necessary to determine their inventories of volatiles and organic compounds, material delivered to the inner Solar System during the Late Heavy Bombardment. What chemical and geological processes shaped the small bodies that merged to form the planets in our Solar System? AJAX investigates the asteroid internal structure, geology, and regolith by using global high-resolution stereo and multispectral imaging, determining density and estimating interior porosity by measuring gravity, and measuring regolith mechanical properties by landing. AJAX's science phase starts with search for natural satellites and dust lifted by possible cometary activity and shape and pole position determination. AJAX descends to lower altitudes for global mapping, and conducts a low flyover for high-resolution surface characterization and measurement of hydrogen abundance. Finally, it deploys a small landed package, which measures elemental abundances and physical properties of the regolith. AJAX's science data will result in an improved understanding of the early stages of planetary accretion by comparing a Trojan asteroid with near-Earth targets of OSIRIS-REx, Hayabusa 2, and NEAR, and the Kuiper Belt-derived targets of Rosetta and New Horizons.

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.

Optimal design of near-Earth asteroid sample-return trajectories in the Sun-Earth-Moon system

NASA Astrophysics Data System (ADS)

He, Shengmao; Zhu, Zhengfan; Peng, Chao; Ma, Jian; Zhu, Xiaolong; Gao, Yang

2016-08-01

In the 6th edition of the Chinese Space Trajectory Design Competition held in 2014, a near-Earth asteroid sample-return trajectory design problem was released, in which the motion of the spacecraft is modeled in multi-body dynamics, considering the gravitational forces of the Sun, Earth, and Moon. It is proposed that an electric-propulsion spacecraft initially parking in a circular 200-km-altitude low Earth orbit is expected to rendezvous with an asteroid and carry as much sample as possible back to the Earth in a 10-year time frame. The team from the Technology and Engineering Center for Space Utilization, Chinese Academy of Sciences has reported a solution with an asteroid sample mass of 328 tons, which is ranked first in the competition. In this article, we will present our design and optimization methods, primarily including overall analysis, target selection, escape from and capture by the Earth-Moon system, and optimization of impulsive and low-thrust trajectories that are modeled in multi-body dynamics. The orbital resonance concept and lunar gravity assists are considered key techniques employed for trajectory design. The reported solution, preliminarily revealing the feasibility of returning a hundreds-of-tons asteroid or asteroid sample, envisions future space missions relating to near-Earth asteroid exploration.

Volatiles in asteroids

NASA Astrophysics Data System (ADS)

Campins, H.

2014-07-01

For more than three decades, hydrated minerals have been identified in asteroids. The distribution of these minerals among asteroid spectral types and heliocentric distance has been somewhat unexpected, and there is also diversity in the composition of these hydrated minerals (e.g., Takir and Emery 2012). In addition, water ice and organic molecules have been detected on two asteroids (Campins et al. 2010; Rivkin and Emery 2010; Licandro et al. 2011) and water vapor is emanating from (1) Ceres (Küppers et al. 2014). These discoveries have important implications on current views of primitive asteroids, the nature of active asteroids or main-belt comets, the dynamics of the early Solar System, and the delivery of water and organic molecules to the Earth. They are also relevant to several space missions, including Dawn, Gaia, Hayabusa2, OSIRIS-REx ,and WISE.

Visual and near-IR spectrophotometry of asteroids

NASA Technical Reports Server (NTRS)

Lebofsky, Larry A.

1991-01-01

We have been continuing our studies of the spectral properties of dark asteroids in the solar system. From these studies we expect to learn about the distribution of volatile materials, such as water in clay materials (water of hydration) and how the asteroids may relate to the comets. Our most recent work has been concentrating on simultaneous visual and near infrared photometry near Earth, main belt, and trojan asteroids. We have made observations of some unusual asteroids such as Chiron, which has recently shown cometary activity, and 944 Hidalgo, which has a comet-like orbit. We have also begun studies of the small, dark satellites of Mars and Jupiter in order to understand better how they may relate to the steroids. Could they actually be captured asteroids or comets?

Roadmap of next generation minor body explorations in Japan

NASA Astrophysics Data System (ADS)

Yano, H.

As of the early 2004, more than 250,000 minor bodies in the solar system have been detected. Among them, several thousands of asteroids are determined orbital elements well and even multi-band spectroscopic observation from ground enables us to classify taxonomy of them in statistically valid numbers. On the other hand, there have been several 10,000s of meteorite and cosmic dust samples already collected in the terrestrial environment. Thus, asteroid studies in statistical manners are practically conducted by ground observation and meteoritic analyses. It is a unique contribution of planetary exploration to provide the ground truth which bridges between abundant database of the ground observation and that of the meteoritic analyses, by bringing samples back to the Earth from a particular asteroid investigated in-situ. In May 2003, JAXA/ISAS successfully launched the Hayabusa (MUSES-C) spacecraft as the first kind of such minor body exploration, which will bring surface samples of an S-type NEO back to the Earth in mid 2007. Many of Japanese planetary scientists hope to advance such sample return strategies as their new expertise in the post-Hayabusa era. Now the ISAS new minor body exploration working group is about to start. Mission candidates include multiple sample returns from known spectra asteroids, in order to complete the asteroid taxonomy-meteoritic connection issue as early as possible (next 10-20 years) with possible international collaborations. One of such ideas is the multiple rendezvous sample return mission to known spectra NEOs of both primitive types (i.e., C, P/D) and differentiated types (e.g., V, M). Another is fly-by investigation and sample collection of multiple asteroids that belong to a single main-belt family. It will provide direct information of the interior as well as collisional history of their parent body, a refractory planetesimal disrupted by mutual collisions in the early stage of the Solar System evolution. One scenario targets the Koronis family including the Ida-Gaspra system, the only family asteroid visited by spacecraft in the past, and its dust band. Another aims the Nysa-Polana Family, which has several spectral types. Also what ISAS is planning is the solar powered sail mission which will make fly-by observations of main belt asteroids as well as Jovian Trojan asteroids, most of which are D-type asteroids with the absence of water absorption lines. Understanding generic connections among the Trojans, short-period cometary nucleus and the outermost D-type asteroids in the main belt may be a clue of how to distinguish between asteroids and comets, depending upon where they originated with respect to heliocentric distance in the early solar system.

Asteroid and Comet Census from WISE

NASA Image and Video Library

2010-10-04

This frame from a video demonstrates how NASA Wide-field Infrared Survey Explorer surveys asteroids and comets in the solar system. Perspective shown here is looking down from high above Earth North Pole, a kind of bird eye view of the solar system.

Using ANTS to explore small body populations in the solar system.

NASA Astrophysics Data System (ADS)

Clark, P. E.; Rilee, M.; Truszkowski, W.; Curtis, S.; Marr, G.; Chapman, C.

2001-11-01

ANTS (Autonomous Nano-Technology Swarm), a NASA advanced mission concept, is a large (100 to 1000 member) swarm of pico-class (1 kg) totally autonomous spacecraft that prospect the asteroid belt. Little data is available for asteroids because the vast majority are too small to be observed except in close proximity. Light curves are available for thousands of asteroids, confirmed trajectories for tens of thousands, detailed shape models for approximately ten. Asteroids originated in the transitional region between the inner (rocky) and outer (solidified gases) solar system. Many have remained largely unmodified since formation, and thus have more primitive composition than planetary surfaces. Determination of the systematic distribution of physical and compositional properties within the asteroid population is crucial in the understanding of solar system formation. The traditional exploration approach of using few, large spacecraft for sequential exploration, could be improved. Our far more cost-effective approach utilizes distributed intelligence in a swarm of tiny highly maneuverable spacecraft, each with specialized instrument capability (e.g., advanced computing, imaging, spectrometry). NASA is at the forefront of Intelligent Software Agents (ISAs) research, performing experiments in space and on the ground to advance deliberative and collaborative autonomous control techniques. The advanced development under consideration here is in the use of ISAs at a strategic level, to explore remote frontiers of the solar system, potentially involving a large class of objects such as asteroids. Supervised clusters of spacecraft operate simultaneously within a broadly defined framework of goals to select targets (> 1000) from among available candidates while developing scenarios for studying targets. Swarm members use solar sails to fly directly to asteroids > 1 kilometer in diameter, and then perform maneuvers appropriate for the instrument carried, ranging from hovering to orbiting. Selected members return with data and are replaced as needed.

Observation of freakish-asteroid-discovered-resembles support my idea that many dark comets were arrested and lurked in the solar system after every impaction

NASA Astrophysics Data System (ADS)

Cao, Dayong

2014-03-01

New observations show that some asteroids are looked like comets. http://www.astrowatch.net/2013/11/freakish-asteroid-discovered-resembles.html, http://www.astrowatch.net/2013/11/astronomers-puzzle-over-newfound.html. It supports my idea that ``many dark comets with very special tilted orbits were arrested and lurked in the solar system'' - ``Sun's companion-dark hole seasonal took its dark comets belt and much dark matter to impact near our earth. And some of them probability hit on our earth. So this model kept and triggered periodic mass extinctions on our earth every 25 to 27 million years. After every impaction, many dark comets with very special tilted orbits were arrested and lurked in the solar system. Because some of them picked up many solar matter, so it looked like the asteroids. When the dark hole-Tyche goes near the solar system again, they will impact near planets.'' The idea maybe explains why do the asteroid looks like the comet? Where are the asteroids come from? What relationship do they have with the impactions and extinctions? http://meetings.aps.org/link/BAPS.2011.CAL.C1.7, http://meetings.aps.org/Meeting/CAL12/Event/181168, http://meetings.aps.org/link/BAPS.2013.MAR.H1.267. During 2009 to 2010, I had presented there are many dark comets like dark Asteroids near the orbit of Jupiter in ASP Meetings. In 2010, NASA's WISE found them. http://meetings.aps.org/link/BAPS.2011.APR.K1.17, http://www.nasa.gov/mission_pages/WISE/news/wise20100122.html Avoid Earth Extinction Associ.

Geotechnical Tests on Asteroid Simulant Orgueil

NASA Technical Reports Server (NTRS)

Garcia, Alexander D'marco

2017-01-01

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.

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.

The Asteroid Impact Mission (AIM): Studying the geophysics of small binaries, measuring asteroid deflection and studying impact physics

NASA Astrophysics Data System (ADS)

Kueppers, Michael; Michel, Patrick; AIM Team

2016-10-01

Binary asteroids and their formation mechanisms are of particular interest for understanding the evolution of the small bodies in the solar system. Also, hazards to Earth from impact of near-Earth asteroids and their mitigation have drawn considerable interest over the last decades.Those subjects are both addressed by ESA's Asteroid Impact mission, which is part of the Asteroid Impact & Deflection Assessment (AIDA) currently under study in collaboration between NASA and ESA. NASA's DART mission will impact a projectile into the minor component of the binary near-Earth asteroid (65803) Didymos in 2022. The basic idea is to demonstrate the effect of the impact on the orbital period of the secondary around the primary. ESA's AIM will monitor the Didymos system for several months around the DART impact time.AIM will be launched in aurumn 2020. It is foreseen to arrive at Didymos in April 2022. The mission takes advantage of a close approach of Didymos to Earth. The next opportunity would arise in 2040 only.AIM will stay near Didymos for approximately 6 months. Most of the time it will be placed on the illuminated side of the system, at distances of approximately 35 km and 10 km. AIM is expected to move away from Didymos for some time around the DART impact.The reference payload for AIM includes two visual imagers, a hyperspectral camera, a lidar, a thermal infrared imager, a monostatic high frequency radar, and a bistatic low frequency radar. In addition, AIM will deploy a small lander on the secondary asteroid, and two cubesats that will be used for additional, more risky investigations close to or on the surface of the asteroid.Major contributions from AIM are expected in the study of the geophysics of small asteroids (including for the first time, radar measurements of an interior structure), the formation of binary asteroids, the momentum enhancement factor from the DART impact (through measuring the mass and the change of orbit of the seondary), and impact physics through observing the outcome of an impact with well known impact conditions. In addition, AIM will test new technologies (Cubesats in interplanetary space, Intersatellite links, optical telecommunication in deep space, infrared navigation).

Chondrites, S asteroids, and space weathering: Thumping noises from the coffin?

NASA Technical Reports Server (NTRS)

Fanale, F. P.; Clark, B. E.

1993-01-01

Most of the spectral characteristics of ordinary chondrites and S-asteroids in the visible and infrared can be reduced to three numerical values. These values represent the depth of the absorption band resulting from octahedrally coordinated Fe(sup 2+), the reflectance at 0.56 microns and the slope of the continuum (as measured according to convention). By plotting these three characteristics, it is possible to immediately compare the spectral characteristics of large numbers of ordinary chondrites and S-asteroids. Commonality of spectral characteristics between these populations can thus be evaluated on the basis of overlap in position on three two-coordinate systems: albedo vs. band depth, band depth vs. slope, and slope vs. albedo. In order to establish identity, members of the two populations must overlap on all three of these independent parameter spaces. In this coordinate system, spectra of 23 ordinary chondrites (representing all metamorphic grades), and 39 S-asteroids were compared. It was found that there was no overlap between the two populations in terms of the slope vs. band depth parameters, nor were most chondrites identical to the S-asteroids with respect to the other criteria. However, the controversial question remains: Where are the parent bodies of the chondrites? Perhaps an even more critical question is: Where are our samples of the S-asteroids? Considering the geography of the asteroid belt and the theory that early solar-system electromagnetic induction heating differentiated protoasteroids in the inner portion of the main belt, it was suggested that although S-asteroids and ordinary chondrites have very similar mineralogy, the S-asteroids are mixtures of metallic nickel iron and silicates which resulted from magmatism induced by electromagnetic heating whereas chondrites were only slightly metamorphosed nebular condensates. In this scenario chondrites would have been derived from a population of bodies with thermal lag times so short that they were not subjected to melting during the phase of the electromagnetic induction heating event but only to various degrees of pervasive metamorphism. Furthermore, these objects would then have been too small to be observed and systematically included in the library of asteroidal spectra. It was also suggested that the parametric distribution of S-asteroid spectra could be reproduced by mixing various proportions of NiFe meteorite and achondritic materials. This has also been demonstrated in the laboratory.

Solar Power at Play

NASA Astrophysics Data System (ADS)

2007-03-01

For the very first time, astronomers have witnessed the speeding up of an asteroid's rotation, and have shown that it is due to a theoretical effect predicted but never seen before. The international team of scientists used an armada of telescopes to discover that the asteroid's rotation period currently decreases by 1 millisecond every year, as a consequence of the heating of the asteroid's surface by the Sun. Eventually it may spin faster than any known asteroid in the solar system and even break apart. ESO PR Photo 11a/07 ESO PR Photo 11a/07 Asteroid 2000 PH5 "The Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect is believed to alter the way small bodies in the Solar System rotate," said Stephen Lowry (Queens University Belfast, UK), lead-author of one of the two companion papers in which this work is reported [1, 2]. "The warming caused by sunlight hitting the surfaces of asteroids and meteoroids leads to a gentle recoil effect as the heat is released," he added. "By analogy, if one were to shine light on a propeller over a long enough period, it would start spinning." Although this is an almost immeasurably weak force, its effect over millions of years is far from negligible. Astronomers believe the YORP effect may be responsible for spinning some asteroids up so fast that they break apart, perhaps leading to the formation of double asteroids. Others may be slowed down so that they take many days to complete a full turn. The YORP effect also plays an important role in changing the orbits of asteroids between Mars and Jupiter, including their delivery to planet-crossing orbits, such as those of near-Earth asteroids. Despite its importance, the effect has never been seen acting on a solar system body, until now. Using extensive optical and radar imaging from powerful Earth-based observatories, astronomers have directly observed the YORP effect in action on a small near-Earth asteroid, known as (54509) 2000 PH5. Shortly after its discovery in 2000, it was realised that asteroid 2000 PH5 would be the ideal candidate for such a YORP detection. With a diameter of just 114 metres, it is relatively small and so more susceptible to the effect. Also, it rotates very fast, with one 'day' on the asteroid lasting just over 12 Earth minutes, implying that the YORP effect may have been acting on it for some time. With this in mind, the team of astronomers undertook a long term monitoring campaign of the asteroid with the aim of detecting any tiny changes in its rotation speed. Over a 4-year time span, Stephen Lowry, Alan Fitzsimmons and colleagues took images of the asteroid at a range of telescope sites including ESO's 8.2-m Very Large Telescope array and 3.5-m New Technology Telescope in Chile, the 3.5-m telescope at Calar Alto, Spain, along with a suite of other telescopes from the Czech Republic, the Canary Islands, Hawaii, Spain and Chile. With these facilities the astronomers measured the slight brightness variations as the asteroid rotated. ESO PR Photo 11b/07 ESO PR Photo 11b/07 Radar Images of 2000 PH5 Over the same time period, the radar team led by Patrick Taylor and Jean-Luc Margot of Cornell University employed the unique capabilities of the Arecibo Observatory in Puerto Rico and the Goldstone radar facility in California to observe the asteroid by 'bouncing' a radar pulse off the asteroid and analysing its echo. "With this technique we can reconstruct a 3-D model of the asteroid's shape, with the necessary detail to allow a comparison between the observations and theory," said Taylor. After careful analysis of the optical data, the asteroid's spin rate was seen to steadily increase with time, at a rate that can be explained by the YORP theory. Critically, the effect was observed year after year, for more than 4 years. Furthermore, this number was elegantly supported via analysis of the combined radar and optical data, as it was required that the asteroid is increasing its spin rate at exactly this rate in order for a satisfactory 3-D shape model to be determined. ESO PR Video 11/07 ESO PR Video 11c/07 Watch the Asteroid Move! To predict what will happen to the asteroid in the future, Lowry and his colleagues performed detailed computer simulations using the measured strength of the YORP effect and the detailed shape model. They found that the orbit of the asteroid about the Sun could remain stable for up to the next 35 million years, allowing the rotation period to be reduced by a factor of 36, to just 20 seconds, faster than any asteroid whose rotation has been measured until now. "This exceptionally fast spin-rate could force the asteroid to reshape itself or even split apart, leading to the birth of a new double system," said Lowry.

Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2017 October-December

NASA Astrophysics Data System (ADS)

Warner, Brian D.

2018-04-01

Lightcurves for 18 main-belt asteroids were obtained at the Center for Solar System Studies-Palmer Divide Station (CS3-PDS) from 2017 October-December. All but one of the asteroids were targets of opportunity, i.e., in the field of planned targets, which demonstrates a good reason for data mining images.

Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2017 July Through October

NASA Astrophysics Data System (ADS)

Warner, Brian D.

2018-01-01

Lightcurves for 17 main-belt asteroids were obtained at the Center for Solar System Studies-Palmer Divide Station (CS3-PDS) from 2017 July through October. All but two of the asteroids were targets of opportunity, i.e., in the field of planned targets, demonstrating a good reason for data mining images.

Artist's Concept of Psyche Spacecraft with Five-Panel Array

NASA Image and Video Library

2017-05-23

This artist's-concept illustration depicts the spacecraft of NASA's Psyche mission near the mission's target, the metal asteroid Psyche. The artwork was created in May 2017 to show the five-panel solar arrays planned for the spacecraft. The spacecraft's structure will include power and propulsion systems to travel to, and orbit, the asteroid. These systems will combine solar power with electric propulsion to carry the scientific instruments used to study the asteroid through space. The mission plans launch in 2022 and arrival at Psyche, between the orbits of Mars and Jupiter, in 2026. This selected asteroid is made almost entirely of nickel-iron metal. It offers evidence about violent collisions that created Earth and other terrestrial planets. https://photojournal.jpl.nasa.gov/catalog/PIA21499

Synergistic approach of asteroid exploitation and planetary protection

NASA Astrophysics Data System (ADS)

Sanchez, J. P.; McInnes, C. R.

2012-02-01

The asteroid and cometary impact hazard has long been recognised as an important issue requiring risk assessment and contingency planning. At the same time asteroids have also been acknowledged as possible sources of raw materials for future large-scale space engineering ventures. This paper explores possible synergies between these two apparently opposed views; planetary protection and space resource exploitation. In particular, the paper assumes a 5 tonne low-thrust spacecraft as a baseline for asteroid deflection and capture (or resource transport) missions. The system is assumed to land on the asteroid and provide a continuous thrust able to modify the orbit of the asteroid according to the mission objective. The paper analyses the capability of such a near-term system to provide both planetary protection and asteroid resources to Earth. Results show that a 5 tonne spacecraft could provide a high level of protection for modest impact hazards: airburst and local damage events (caused by 15-170 m diameter objects). At the same time, the same spacecraft could also be used to transport to bound Earth orbits significant quantities of material through judicious use of orbital dynamics and passively safe aero-capture manoeuvres or low energy ballistic capture. As will be shown, a 5 tonne low-thrust spacecraft could potentially transport between 12 and 350 times its own mass of asteroid resources by means of ballistic capture or aero-capture trajectories that pose very low dynamical pressures on the object.

Building Blocks of the Terrestrial Planets: Mineralogy of Hungaria Asteroids

NASA Astrophysics Data System (ADS)

Lucas, Michael; Emery, J. P.

2013-10-01

Deciphering the mineralogy of the Hungaria asteroids has the potential to place constraints on the material from which the terrestrial planets accreted. Among asteroids with semi-major axes interior to the main-belt (e.g., Hungarias, Mars-crossers, and near-Earth asteroids), only the Hungarias are located in relatively stable orbital space. Hungaria asteroids have likely resided in this orbital space since the planets completed their migration to their current orbits. The accretion and igneous differentiation of primitive asteroids appears to be a function of chronology and heliocentric distance. However, differentiated bodies that originated in the terrestrial planet region were either accreted or scattered out of this region early in solar system history. Thus, the Hungaria asteroids represent the closest reservoir of in situ material to the terrestrial planet region from early in solar system history. We present VISNIR 0.45-2.45 µm) and NIR spectra 0.65-2.45 µm) spectra of 24 Hungaria group (objects in similar orbital space) asteroids. Our NIR data (17 objects) were acquired using the InfraRed Telescope Facility and was supplemented with available visible data. Spectra of seven objects were obtained from the MIT-UH-IRTF survey. We distinguish our sample between Hungaria family (presumed fragments of parent 434 Hungaria; 2 objects) and Hungaria background (group minus family 22 objects) asteroids using proper orbital elements. The classification of each asteroid is determined using the taxonomy of Bus-DeMeo. We find that S- and S-subtypes are prevalent among the Hungaria background population (17/22). Spectral band parameters measurements (i.e., Band I and Band II centers and depths, and Band Area Ratio) indicate that eight of these S-types are analogous with undifferentiated ordinary chondrites (SIV “boot” of S-subtypes plot). Mafic silicate mineral abundances and compositions derived for these SIV asteroids mainly correlate with L chondrites. However, one object is an SIII subtype (possible ureilite analog), while two asteroids are SVI subtypes (possible primitive achondrite analog). Family member 6447 Terrycole is a Xe-type, consistent with the taxonomic classification of the parent 434 Hungaria.

Capture orbits around asteroids by hitting zero-velocity curves

NASA Astrophysics Data System (ADS)

Wang, Wei; Yang, Hongwei; Zhang, Wei; Ma, Guangfu

2017-12-01

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.

Candidate Binary Trojan and Hilda Asteroids from Rotational Light Curves

NASA Astrophysics Data System (ADS)

Sonnett, Sarah M.; Mainzer, Amy K.; Grav, Tommy; Masiero, Joseph R.; Bauer, James M.; Kramer, Emily A.

2017-10-01

Jovian Trojans (hereafter, Trojans) are asteroids in stable orbits at Jupiter's L4 and L5 Lagrange points, and Hilda asteroids are inwards of the Trojans in 3:2 mean-motion resonance with Jupiter. Due to their special dynamical properties, observationally constraining the formation location and dynamical histories of Trojans and HIldas offers key input for giant planet migration models. A fundamental parameter in assessing formation location is the bulk density - with low-density objects associated with an ice-rich formation environment in the outer solar system and high-density objects typically linked to the warmer inner solar system. Bulk density can only be directly measured during a close fly-by or by determining the mutual orbits of binary asteroid systems. With the aim of determining densities for a statistically significant sample of Trojans and Hildas, we are undertaking an observational campaign to confirm and characterize candidate binary asteroids published in Sonnett et al. (2015). These objects were flagged as binary candidates because their large NEOWISE brightness variations imply shapes so elongated that they are not likely explained by a singular equilibrium rubble pile and instead may be two elongated, gravitationally bound asteroids. We are obtaining densely sampled rotational light curves of these possible binaries to search for light curve features diagnostic of binarity and to determine the orbital properties of any confirmed binary systems by modeling the light curve. We compare the We present an update on this follow-up campaign and comment on future steps.

A brief visit from a red and extremely elongated interstellar asteroid.

PubMed

Meech, Karen J; Weryk, Robert; Micheli, Marco; Kleyna, Jan T; Hainaut, Olivier R; Jedicke, Robert; Wainscoat, Richard J; Chambers, Kenneth C; Keane, Jacqueline V; Petric, Andreea; Denneau, Larry; Magnier, Eugene; Berger, Travis; Huber, Mark E; Flewelling, Heather; Waters, Chris; Schunova-Lilly, Eva; Chastel, Serge

2017-12-21

None of the approximately 750,000 known asteroids and comets in the Solar System is thought to have originated outside it, despite models of the formation of planetary systems suggesting that orbital migration of giant planets ejects a large fraction of the original planetesimals into interstellar space. The high predicted number density of icy interstellar objects (2.4 × 10 -4 per cubic astronomical unit) suggests that some should have been detected, yet hitherto none has been seen. Many decades of asteroid and comet characterization have yielded formation models that explain the mass distribution, chemical abundances and planetary configuration of the Solar System today, but there has been no way of telling whether the Solar System is typical of planetary systems. Here we report observations and analysis of the object 1I/2017 U1 ('Oumuamua) that demonstrate its extrasolar trajectory, and that thus enable comparisons to be made between material from another planetary system and from our own. Our observations during the brief visit by the object to the inner Solar System reveal it to be asteroidal, with no hint of cometary activity despite an approach within 0.25 astronomical units of the Sun. Spectroscopic measurements show that the surface of the object is spectrally red, consistent with comets or organic-rich asteroids that reside within the Solar System. Light-curve observations indicate that the object has an extremely oblong shape, with a length about ten times its width, and a mean radius of about 102 metres assuming an albedo of 0.04. No known objects in the Solar System have such extreme dimensions. The presence of 'Oumuamua in the Solar System suggests that previous estimates of the number density of interstellar objects, based on the assumption that all such objects were cometary, were pessimistically low. Planned upgrades to contemporary asteroid survey instruments and improved data processing techniques are likely to result in the detection of more interstellar objects in the coming years.

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.

Asteroid Redirection Mission Evaluation Using Multiple Landers

NASA Astrophysics Data System (ADS)

Bazzocchi, Michael C. F.; Emami, M. Reza

2018-06-01

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.

Japanese Studies of Asteroids Following the Discovery of the Hirayama Families

NASA Astrophysics Data System (ADS)

Nakamura, Tsuko

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.

A census of the asteroid belt

NASA Technical Reports Server (NTRS)

Tedesco, E. F.; Veeder, G. J.

1991-01-01

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.

Asteroid Redirection Mission Evaluation Using Multiple Landers

NASA Astrophysics Data System (ADS)

Bazzocchi, Michael C. F.; Emami, M. Reza

2018-01-01

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.

The IRAS Minor Planet Survey

NASA Technical Reports Server (NTRS)

Tedesco, Edward F.; Veeder, Glenn J.; Fowler, John W.; Chillemi, Joseph R.

1992-01-01

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.

Mine Planning for Asteroid Orebodies

NASA Astrophysics Data System (ADS)

Gertsch, L. S.; Gertsch, R. E.

2000-01-01

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.

Ion Beam Deflection (AKA Push-Me/Pull-You)

NASA Technical Reports Server (NTRS)

Brophy, John

2013-01-01

The Ion Beam Deflection provides the following potential advantages over other asteroid deflection systems. Like the gravity tractor, it doesn't require despinning of the asteroid. Unlike the gravity tractor, it provides a significantly higher coupling force that is independent of the asteroid size. The concept could be tested as part of the baseline Asteroid Redirect Robotic Mission. The thrust and total impulse are entirely within the design of the SEP vehicle. The total impulse is potentially competitive with kinetic impactors and eliminates the need for a second rendezvous spacecraft.?Gridded ion thrusters provide beam divergence angles of a few degrees enabling long stand-off distances from the asteroid. Mitigating control issues. Minimizing back-sputter contamination risks

The Tagish Lake meteorite: a possible sample from a D-type asteroid.

PubMed

Hiroi, T; Zolensky, M E; Pieters, C M

2001-09-21

A new type of carbonaceous chondrite, the Tagish Lake meteorite, exhibits a reflectance spectrum similar to spectra observed from the D-type asteroids, which are relatively abundant in the outer solar system beyond the main asteroid belt and have been inferred to be more primitive than any known meteorite. Until the Tagish Lake fall, these asteroids had no analog in the meteorite collections. The Tagish Lake meteorite is a carbon-rich (4 to 5 weight %), aqueously altered carbonaceous chondrite and contains high concentrations of presolar grains and carbonate minerals, which is consistent with the expectation that the D-type asteroids were originally made of primitive materials and did not experience any extensive heating.

The Size Frequency Distribution of Small Main-Belt Asteroids

NASA Technical Reports Server (NTRS)

Burt, Brian J.; Trilling, David E.; Hines, Dean C.; Stapelfeldt, Karl R.; Rebull, Luisa M.; Fuentes, Cesar I.; Hulsebus, Alan

2012-01-01

The asteroid size distribution informs us about the formation and composition of the Solar System. We build on our previous work in which we harvest serendipitously observed data of the Taurus region and measure the brightness and size distributions of Main-belt asteroids. This is accomplished with the highly sensitive MIPS 24 micron channel. We expect to catalog 104 asteroids, giving us a statistically significant data set. Results from this investigation will allow us to characterize the total population of small, Main-belt asteroids. Here we will present new results on the completeness of our study; on the presence of size distribution variations with inclination and radial distance in the belt; and early result on other archival fields.

A Photometric Study of Phocaea Group Asteroid 1584 Fuji

NASA Astrophysics Data System (ADS)

Drake, J. S.

2004-05-01

Observations of Phocaea group asteroid 1584 Fuji with the 31-inch telescope at Lowell Observatory in Arizona and the 24-inch telescope at Britton Observatory at Dickinson College in Pennsylvania from 31 January 2004 to 28 February 2004 indicate a sinusoidal lightcurve with a period of 14.89 ± 0.01 hours, in conflict with published results. Reduction of these data to a standard magnitude system indicate a V-band amplitude of 0.13 ± 0.02 magnitudes, further diverging from the accepted value. Application of the IAU Two-Parameter magnitude system for asteroids permits an estimation of the body's diameter. I compare these parameters with those published for Fuji's companions in the Phocaea group, other S-type objects in the main belt, and asteroids of similar size throughout the Solar System. I thank Dickinson College and the Arizona Space Grant Consortium for their financial support.

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.

A CubeSat Asteroid Mission: Design Study and Trade-Offs

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Oleson, Steven R.; McGuire, Melissa; Hepp, Aloysius; Stegeman, James; Bur, Mike; Burke, Laura; Martini, Michael; Fittje, James E.; Kohout, Lisa;

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.

Hydrated Minerals on Asteroids: The Astronomical Record

NASA Technical Reports Server (NTRS)

Rivkin, A. S.; Howell, E. S.; Vilas, F.; Lebofsky, L. A.

2002-01-01

Knowledge of the hydrated mineral inventory on the asteroids is important for deducing the origin of Earth's water, interpreting the meteorite record, and unraveling the processes occurring during the earliest times in solar system history. Reflectance spectroscopy shows absorption features in both the 0.6-0.8 and 2.5-3.5 micrometers regions, which are diagnostic of or associated with hydrated minerals. Observations in those regions show that hydrated minerals are common in the mid-asteroid belt, and can be found in unexpected spectral groupings, as well. Asteroid groups formerly associated with mineralogies assumed to have high temperature formation, such as M- and E-class asteroids, have been observed to have hydration features in their reflectance spectra. Some asteroids have apparently been heated to several hundred degrees Celsius, enough to destroy some fraction of their phyllosilicates. Others have rotational variation suggesting that heating was uneven. We summarize this work, and present the astronomical evidence for water- and hydroxyl-bearing minerals on asteroids.

Potential Mission Scenarios Post Asteroid Crewed Mission

NASA Technical Reports Server (NTRS)

Lopez, Pedro, Jr.; McDonald, Mark A.

2015-01-01

A deep-space mission has been proposed to identify and redirect an asteroid to a distant retrograde orbit around the moon, and explore it by sending a crew using the Space Launch System and the Orion spacecraft. The Asteroid Redirect Crewed Mission (ARCM), which represents the third segment of the Asteroid Redirect Mission (ARM), could be performed on EM-3 or EM-4 depending on asteroid return date. Recent NASA studies have raised questions on how we could progress from current Human Space Flight (HSF) efforts to longer term human exploration of Mars. This paper will describe the benefits of execution of the ARM as the initial stepping stone towards Mars exploration, and how the capabilities required to send humans to Mars could be built upon those developed for the asteroid mission. A series of potential interim missions aimed at developing such capabilities will be described, and the feasibility of such mission manifest will be discussed. Options for the asteroid crewed mission will also be addressed, including crew size and mission duration.

Disaggregation of small, cohesive rubble pile asteroids due to YORP

NASA Astrophysics Data System (ADS)

Scheeres, D. J.

2018-04-01

The implication of small amounts of cohesion within relatively small rubble pile asteroids is investigated with regard to their evolution under the persistent presence of the YORP effect. We find that below a characteristic size, which is a function of cohesive strength, density and other properties, rubble pile asteroids can enter a "disaggregation phase" in which they are subject to repeated fissions after which the formation of a stabilizing binary system is not possible. Once this threshold is passed rubble pile asteroids may be disaggregated into their constituent components within a finite time span. These constituent components will have their own spin limits - albeit potentially at a much higher spin rate due to the greater strength of a monolithic body. The implications of this prediction are discussed and include modification of size distributions, prevalence of monolithic bodies among meteoroids and the lifetime of small rubble pile bodies in the solar system. The theory is then used to place constraints on the strength of binary asteroids characterized as a function of their type.

Arecibo Radar Observations of Near-Earth Asteroids

NASA Astrophysics Data System (ADS)

Rivera-Valentin, Edgard G.; Taylor, Patrick A.; Virkki, Anne; Saran Bhiravarasu, Sriram; Venditti, Flaviane; Zambrano-Marin, Luisa Fernanda; Aponte-Hernandez, Betzaida

2017-10-01

The Arecibo S-Band (2.38 GHz, 12.6 cm; 1 MW) planetary radar system at the 305-m William E. Gordon Telescope in Arecibo, Puerto Rico is the most active, most powerful, and most sensitive planetary radar facility in the world. As such, Arecibo is vital for post-discovery characterization and orbital refinement of near-Earth asteroids. Since August 2016, the program has observed 100 near-Earth asteroids (NEAs), of which 38 are classified as potentially hazardous to Earth and 31 are compliant with the NASA Near-Earth Object Human Space Flight Accessible Targets Study (NHATS). Arecibo observations are critical for identifying NEAs that may be on a collision course with Earth in addition to providing detailed physical characterization of the objects themselves in terms of size, shape, spin, and surface properties, which are valuable for assessing impact mitigation strategies. Here, we will present a sampling of the asteroid zoo observed by Arecibo, including press-noted asteroids 2014 JO25 and the (163693) Atira binary system.

Momentum Management for the NASA Near Earth Asteroid Scout Solar Sail Mission

NASA Technical Reports Server (NTRS)

Heaton, Andrew; Diedrich, Benjamin L.; Orphee, Juan; Stiltner, Brandon; Becker, Christopher

2017-01-01

The Momentum Management (MM) system is described for the NASA Near Earth Asteroid Scout (NEA Scout) cubesat solar sail mission. Unlike many solar sail mission proposals that used solar torque as the primary or only attitude control system, NEA Scout uses small reaction wheels (RW) and a reaction control system (RCS) with cold gas thrusters, as described in the abstract "Solar Sail Attitude Control System for Near Earth Asteroid Scout Cubesat Mission." The reaction wheels allow fine pointing and higher rates with low mass actuators to meet the science, communication, and trajectory guidance requirements. The MM system keeps the speed of the wheels within their operating margins using a combination of solar torque and the RCS.

Crew Systems for Asteroid Exploration: Concepts for Lightweight & Low Volume EVA Systems

NASA Technical Reports Server (NTRS)

Mueller, Rob; Calle, Carlos; Mantovani, James

2013-01-01

This RFI response is targeting Area 5. Crew Systems for Asteroid Exploration: concepts for lightweight and low volume robotic and extra-vehicular activity (EVA) systems, such as space suits, tools, translation aids, stowage containers, and other equipment. The NASA KSC Surface Systems Office, Granular Mechanics and Regolith Operations (GMRO) Lab and the Electrostatics & Surface Physics Lab (ESPL) are dedicated to developing technologies for operating in regolith environments on target body surfaces. We have identified two technologies in our current portfolio that are highly relevant and useful for crews that will visit a re-directed asteroid in Cis-Lunar Space. Both technologies are at a high TRL of 5/6 and could be rapidly implemented in time for an ARM mission in this decade.

Observation of asteroid 2013 TV135 supports my idea that a new impaction will come in 20 years

NASA Astrophysics Data System (ADS)

Cao, Dayong

2014-03-01

Asteroid 2013 TV135 who will impact in 2023 was newly discovered by Ukrainian astronomers in 2013. It supports my idea that a new impaction will come in 20 years. http://www.nasa.gov/mission_pages/asteroids/news/asteroid20131017.html, http://meetings.aps.org/link/BAPS.2011.DFD.LA.24, http://meetings.aps.org/link/BAPS.2012.APR.K1.78, http://meetings.aps.org/link/BAPS.2013.APR.S2.14. The Sun's companion-dark hole, which is made of dark matter seasonal took its dark comets belt, dark matter, dark lives, and the pressed asteroids belt to impact near our earth. These impactions and dark matter's killers caused seasonal extinctions and produced new species. By many dark comets and asteroids impacting, the dark impaction model is a high probability impaction model; the impaction would not change the orbit of the invisible dark hole, so that it could keep accurate periodicity impactions. With the space-time center, the dark hole system is a negative Einstein's model by ``mass-energy coordinate.'' Sun and Dark hole build up the balance system. Through studying the model, the rule of the impaction can be calculated. Avoid Earth Extinction Association.

COMPASS Final Report: Near Earth Asteroids Rendezvous and Sample Earth Returns (NEARER)

NASA Technical Reports Server (NTRS)

Oleson, Steven R.; McGuire, Melissa L.

2009-01-01

In this study, the Collaborative Modeling for Parametric Assessment of Space Systems (COMPASS) team completed a design for a multi-asteroid (Nereus and 1996 FG3) sample return capable spacecraft for the NASA In-Space Propulsion Office. The objective of the study was to support technology development and assess the relative benefits of different electric propulsion systems on asteroid sample return design. The design uses a single, heritage Orion solar array (SA) (approx.6.5 kW at 1 AU) to power a single NASA Evolutionary Xenon Thruster ((NEXT) a spare NEXT is carried) to propel a lander to two near Earth asteroids. After landing and gathering science samples, the Solar Electric Propulsion (SEP) vehicle spirals back to Earth where it drops off the first sample s return capsule and performs an Earth flyby to assist the craft in rendezvousing with a second asteroid, which is then sampled. The second sample is returned in a similar fashion. The vehicle, dubbed Near Earth Asteroids Rendezvous and Sample Earth Returns (NEARER), easily fits in an Atlas 401 launcher and its cost estimates put the mission in the New Frontier s (NF's) class mission.

An update of the Near-Earth Asteroid Tracking/Maui Space Surveillance System (NEAT/MSSS) collaboration

NASA Technical Reports Server (NTRS)

Bambery, R. J.; Helin, E. F.; Pravdo, S. H.; Lawrence, K. J.; Hicks, M. D.

2002-01-01

Jet Propulsion Laboratory's (JPL) Near-Earth Asteroid Tracking (NEAT) program has two simultaneously-operating, autonomous search systems on two geographically-separated 1.2-m telescopes; one at the Maui Space Surveillance System (NEAT/MSSS) and the other on the Palomar Observatory's Oschin telescope (NEAT/Palomar). This paper will focus exclusively on the NEAT/MSSS system.

Resurfacing asteroids from YORP spin-up and failure

NASA Astrophysics Data System (ADS)

Graves, Kevin J.; Minton, David A.; Hirabayashi, Masatoshi; DeMeo, Francesca E.; Carry, Benoit

2018-04-01

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.

Basalt or Not? Near-infrared Spectra, Surface Mineralogical Estimates, and Meteorite Analogs for 33 Vp-type Asteroids

NASA Astrophysics Data System (ADS)

Hardersen, Paul S.; Reddy, Vishnu; Cloutis, Edward; Nowinski, Matt; Dievendorf, Margaret; Genet, Russell M.; Becker, Savan; Roberts, Rachel

2018-07-01

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.

Preliminary performance analysis of an interplanetary navigation system using asteroid based beacons

NASA Technical Reports Server (NTRS)

Jee, J. Rodney; Khatib, Ahmad R.; Muellerschoen, Ronald J.; Williams, Bobby G.; Vincent, Mark A.

1988-01-01

A futuristic interplanetary navigation system using transmitters placed on selected asteroids is introduced. This network of space beacons is seen as a needed alternative to the overly burdened Deep Space Network. Covariance analyses on the potential performance of these space beacons located on a candidate constellation of eight real asteroids are initiated. Simplified analytic calculations are performed to determine limiting accuracies attainable with the network for geometric positioning. More sophisticated computer simulations are also performed to determine potential accuracies using long arcs of range and Doppler data from the beacons. The results from these computations show promise for this navigation system.

Search for Water in Outer Main Belt Based on AKARI Asteroid Catalog

NASA Astrophysics Data System (ADS)

Usui, Fumihiko

2012-06-01

We propose a program to search water ice on the surface of asteroids in the outer main belt regions, which have high albedo measured with AKARI. The distribution of water in the main belt provides important information to understanding of the formation and evolution of the solar system, because water is a good indicator of temperature in the early solar nebula. The existence of water ice is a hot topic in the solar system studies today. Water ice is recently found in the outer region of the main asteroid belt and some of them are linked to the main belt comets. Brand-new albedo data brought by AKARI opens the possibility of detection of water ice on the C-type asteroids. Here we propose to make the spectroscopic observations with the Subaru telescope in the near-infrared wavelengths to detect water ice on these high-albedo C-type asteroids. Thanks to a large aperture of Subaru telescope and a high altitude of Mauna Kea, it can be only possible to observe a weak signal of the existence of water on the surface of asteroids with a certain S/N. In addition, using the imaging data taken prior to IRCS spectroscopic mode, we intend to seek any comet-like activities by investigating diffuseness of the asteroids, which can be detected by comparing the observed point-spread functions with those of field stars.

Mutual gravitational potential, force, and torque of a homogeneous polyhedron and an extended body: an application to binary asteroids

NASA Astrophysics Data System (ADS)

Shi, Yu; Wang, Yue; Xu, Shijie

2017-11-01

Binary systems are quite common within the populations of near-Earth asteroids, main-belt asteroids, and Kuiper belt asteroids. The dynamics of binary systems, which can be modeled as the full two-body problem, is a fundamental problem for their evolution and the design of relevant space missions. This paper proposes a new shape-based model for the mutual gravitational potential of binary asteroids, differing from prior approaches such as inertia integrals, spherical harmonics, or symmetric trace-free tensors. One asteroid is modeled as a homogeneous polyhedron, while the other is modeled as an extended rigid body with arbitrary mass distribution. Since the potential of the polyhedron is precisely described in a closed form, the mutual gravitational potential can be formulated as a volume integral over the extended body. By using Taylor expansion, the mutual potential is then derived in terms of inertia integrals of the extended body, derivatives of the polyhedron's potential, and the relative location and orientation between the two bodies. The gravitational forces and torques acting on the two bodies described in the body-fixed frame of the polyhedron are derived in the form of a second-order expansion. The gravitational model is then used to simulate the evolution of the binary asteroid (66391) 1999 KW4, and compared with previous results in the literature.

Comet nucleus and asteroid sample return missions

NASA Technical Reports Server (NTRS)

Melton, Robert G.; Thompson, Roger C.; Starchville, Thomas F., Jr.; Adams, C.; Aldo, A.; Dobson, K.; Flotta, C.; Gagliardino, J.; Lear, M.; Mcmillan, C.

1992-01-01

During the 1991-92 academic year, the Pennsylvania State University has developed three sample return missions: one to the nucleus of comet Wild 2, one to the asteroid Eros, and one to three asteroids located in the Main Belt. The primary objective of the comet nucleus sample return mission is to rendezvous with a short period comet and acquire a 10 kg sample for return to Earth. Upon rendezvous with the comet, a tethered coring and sampler drill will contact the surface and extract a two-meter core sample from the target site. Before the spacecraft returns to Earth, a monitoring penetrator containing scientific instruments will be deployed for gathering long-term data about the comet. A single asteroid sample return mission to the asteroid 433 Eros (chosen for proximity and launch opportunities) will extract a sample from the asteroid surface for return to Earth. To limit overall mission cost, most of the mission design uses current technologies, except the sampler drill design. The multiple asteroid sample return mission could best be characterized through its use of future technology including an optical communications system, a nuclear power reactor, and a low-thrust propulsion system. A low-thrust trajectory optimization code (QuickTop 2) obtained from the NASA LeRC helped in planning the size of major subsystem components, as well as the trajectory between targets.

Abodes for life in carbonaceous asteroids?

NASA Astrophysics Data System (ADS)

Abramov, Oleg; Mojzsis, Stephen J.

2011-05-01

Thermal evolution models for carbonaceous asteroids that use new data for permeability, pore volume, and water circulation as input parameters provide a window into what are arguably the earliest habitable environments in the Solar System. Plausible models of the Murchison meteorite (CM) parent body show that to first-order, conditions suitable for the stability of liquid water, and thus pre- or post-biotic chemistry, could have persisted within these asteroids for tens of Myr. In particular, our modeling results indicate that a 200-km carbonaceous asteroid with a 40% initial ice content takes almost 60 Myr to cool completely, with habitable temperatures being maintained for ˜24 Myr in the center. Yet, there are a number of indications that even with the requisite liquid water, thermal energy sources to drive chemical gradients, and abundant organic "building blocks" deemed necessary criteria for life, carbonaceous asteroids were intrinsically unfavorable sites for biopoesis. These controls include different degrees of exothermal mineral hydration reactions that boost internal warming but effectively remove liquid water from the system, rapid (1-10 mm yr -1) inward migration of internal habitable volumes in most models, and limitations imposed by low permeabilities and small pore sizes in primitive undifferentiated carbonaceous asteroids. Our results do not preclude the existence of habitable conditions on larger, possibly differentiated objects such as Ceres and the Themis family asteroids due to presumed longer, more intense heating and possible long-lived water reservoirs.

Drilling, sampling, and sample-handling system for China's asteroid exploration mission

NASA Astrophysics Data System (ADS)

Zhang, Tao; Zhang, Wenming; Wang, Kang; Gao, Sheng; Hou, Liang; Ji, Jianghui; Ding, Xilun

2017-08-01

Asteroid exploration has a significant importance in promoting our understanding of the solar system and the origin of life on Earth. A unique opportunity to study near-Earth asteroid 99942 Apophis will occur in 2029 because it will be at its perigee. In the current work, a drilling, sampling, and sample-handling system (DSSHS) is proposed to penetrate the asteroid regolith, collect regolith samples at different depths, and distribute the samples to different scientific instruments for in situ analysis. In this system, a rotary-drilling method is employed for the penetration, and an inner sampling tube is utilized to collect and discharge the regolith samples. The sampling tube can deliver samples up to a maximum volume of 84 mm3 at a maximum penetration depth of 300 mm to 17 different ovens. To activate the release of volatile substances, the samples will be heated up to a temperature of 600 °C by the ovens, and these substances will be analyzed by scientific instruments such as a mass spectrometer, an isotopic analyzer, and micro-cameras, among other instruments. The DSSHS is capable of penetrating rocks with a hardness value of six, and it can be used for China's asteroid exploration mission in the foreseeable future.

77 FR 3102 - Procedures for Implementing the National Environmental Policy Act

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-23

... from solar system bodies (such as asteroids, comets, planets, dwarf planets, and planetary moons.../program which would return samples to Earth from solar system bodies (such as asteroids, comets, planets, dwarf planets, and planetary moons), which would likely receive a Restricted Earth Return categorization...

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).

Near-Earth Asteroid Tracking with the Maui Space Surveillance System (NEAT/MSSS)

NASA Technical Reports Server (NTRS)

Helin, Eleanor F.; Pravdo, Steven H.; Lawrence, Kenneth J.; Hicks, Michael D.

2001-01-01

Over the last year the Jet Propulsion Laboratory's (JPL) Near-Earth Asteroid Tracking (NEAT) program has made significant progress and now consists of two simultaneously-operating, autonomous search systems on the 1.2-m (48") telescopes: on the Maui Space Surveillance System (NEAT/MSSS) and NEAT/Palomar on the Palomar Observatory's Oschin telescope. This paper will focus exclusively on the NEAT/MSSS system. NEAT/MSSS is operated as a partnership between NASA/JPL and the United States Air Force Research Laboratory (AFRL), utilizing the AFRL 1.2-m telescope on the 3000-m summit of Haleakala, Maui, The USAF Space Command (SPCMD) contributed financial support to build and install the 'NEAT focal reducer' on the MSSS 1.2-m telescope giving it a large field of view (2.5 square degrees), suitable for the near-earth object (NEO),both asteroids and comets, survey. This work was completed in February 2000. AFRL has made a commitment to NEAT/MSSS that allows NEAT to operate full time with the understanding that AFRL participate as partners in NEAT/MSSS and have use of the NEAT camera system for high priority satellite observations during bright time (parts of 12 nights each month). Currently, NEAT has discovered 42 NEAs including 12 larger than 1-km, 5 Potentially Hazardous Asteroids (PHAs), 6 comets, and nearly 25,000 asteroid detections since March 2000.

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.

Asteroid-comet continuum objects in the solar system.

PubMed

Hsieh, Henry H

2017-07-13

In this review presented at the Royal Society meeting, 'Cometary science after Rosetta', I present an overview of studies of small solar system objects that exhibit properties of both asteroids and comets (with a focus on so-called active asteroids). Sometimes referred to as 'transition objects', these bodies are perhaps more appropriately described as 'continuum objects', to reflect the notion that rather than necessarily representing actual transitional evolutionary states between asteroids and comets, they simply belong to the general population of small solar system bodies that happen to exhibit a continuous range of observational, physical and dynamical properties. Continuum objects are intriguing because they possess many of the properties that make classical comets interesting to study (e.g. relatively primitive compositions, ejection of surface and subsurface material into space where it can be more easily studied, and orbital properties that allow us to sample material from distant parts of the solar system that would otherwise be inaccessible), while allowing us to study regions of the solar system that are not sampled by classical comets.This article is part of the themed issue 'Cometary science after Rosetta'. © 2017 The Author(s).

The role of "asteroid taxis" at mastering of Solar system

NASA Astrophysics Data System (ADS)

Steklov, A. F.; Vidmachenko, A. P.

2018-05-01

At the present time, two main tendencies can be considered for the solar system to be habitable: 1) to do something with the objects of the solar system in order to make them suitable for life; and 2), it is necessary to make it so that the interplanetary space of the solar system also becomes suitable for life. We believe that it is better to combine these two trends. To this end, we must develop a methodology for constructing special settlements at asteroids and cometary nuclei. And then, it is necessary to build settlements - the "technospheres" - on the most diverse bodies in the Solar system: asteroids, cometary nuclei, satellites of planets and even on some planets. And, first of all, it is highly desirable to use the own resources of the listed objects. Such "technospheres" should be long-term settlements in interplanetary space and at planetoids. To save energy resources, it is necessary to use near-Earth asteroids enriched with water ice. To successfully implement these concepts, it is necessary at least by two orders of magnitude reduce the cost of such settlements.

Stop hitting yourself: did most terrestrial impactors originate from the terrestrial planets?

NASA Astrophysics Data System (ADS)

Jackson, Alan; Asphaug, Erik; Elkins-Tanton, Linda

2014-11-01

Although the asteroid belt is the main source of impactors in the inner solar system today, it contains only 0.0006 Earth mass, or 0.05 Lunar mass. While the asteroid belt would have been more massive when it formed, it is unlikely to have had greater than 0.5 Lunar mass since the formation of Jupiter and the dissipation of the solar nebula. By comparison, giant impacts onto the terrestrial planets typically release debris equal to several per cent of the planets mass. The Moon-forming impact on Earth and the dichotomy forming impact on Mars, to consider but two of these major events, released 1.3 and 0.3 Lunar mass in debris respectively, many times the mass of the present day asteroid belt. This escaping impact debris is less long lived than the main asteroid belt, as it is injected on unstable, planet-crossing orbits, but this same factor also increases the impact probability with the terrestrial planets and asteroids. We show that as a result terrestrial ejecta played a major role in the impact history of the early inner solar system, and we expect the same is also likely to be true in other planetary systems.

A New Tool for Classifying Small Solar System Objects

NASA Astrophysics Data System (ADS)

Desfosses, Ryan; Arel, D.; Walker, M. E.; Ziffer, J.; Harvell, T.; Campins, H.; Fernandez, Y. R.

2011-05-01

An artificial intelligence program, AutoClass, which was developed by NASA's Artificial Intelligence Branch, uses Bayesian classification theory to automatically choose the most probable classification distribution to describe a dataset. To investigate its usefulness to the Planetary Science community, we tested its ability to reproduce the taxonomic classes as defined by Tholen and Barucci (1989). Of the 406 asteroids from the Eight Color Asteroid Survey (ECAS) we chose for our test, 346 were firmly classified and all but 3 (<1%) were classified by Autoclass as they had been in the previous classification system (Walker et al., 2011). We are now applying it to larger datasets to improve the taxonomy of currently unclassified objects. Having demonstrated AutoClass's ability to recreate existing classification effectively, we extended this work to investigations of albedo-based classification systems. To determine how predictive albedo can be, we used data from the Infrared Astronomical Satellite (IRAS) database in conjunction with the large Sloan Digital Sky Survey (SDSS), which contains color and position data for over 200,000 classified and unclassified asteroids (Ivesic et al., 2001). To judge our success we compared our results with a similar approach to classifying objects using IRAS albedo and asteroid color by Tedesco et al. (1989). Understanding the distribution of the taxonomic classes is important to understanding the history and evolution of our Solar System. AutoClass's success in categorizing ECAS, IRAS and SDSS asteroidal data highlights its potential to scan large domains for natural classes in small solar system objects. Based upon our AutoClass results, we intend to make testable predictions about asteroids observed with the Wide-field Infrared Survey Explorer (WISE).

Understanding asteroid collisional history through experimental and numerical studies

NASA Technical Reports Server (NTRS)

Davis, Donald R.; Ryan, Eileen V.; Weidenschilling, S. J.

1991-01-01

Asteroids can lose angular momentum due to so called splash effect, the analog to the drain effect for cratering impacts. Numerical code with the splash effect incorporated was applied to study the simultaneous evolution of asteroid sized and spins. Results are presented on the spin changes of asteroids due to various physical effects that are incorporated in the described model. The goal was to understand the interplay between the evolution of sizes and spins over a wide and plausible range of model parameters. A single starting population was used both for size distribution and the spin distribution of asteroids and the changes in the spins were calculated over solar system history for different model parameters. It is shown that there is a strong coupling between the size and spin evolution, that the observed relative spindown of asteroids approximately 100 km diameter is likely to be the result of the angular momentum splash effect.

Understanding asteroid collisional history through experimental and numerical studies

NASA Astrophysics Data System (ADS)

Davis, Donald R.; Ryan, Eileen V.; Weidenschilling, S. J.

1991-06-01

Asteroids can lose angular momentum due to so called splash effect, the analog to the drain effect for cratering impacts. Numerical code with the splash effect incorporated was applied to study the simultaneous evolution of asteroid sized and spins. Results are presented on the spin changes of asteroids due to various physical effects that are incorporated in the described model. The goal was to understand the interplay between the evolution of sizes and spins over a wide and plausible range of model parameters. A single starting population was used both for size distribution and the spin distribution of asteroids and the changes in the spins were calculated over solar system history for different model parameters. It is shown that there is a strong coupling between the size and spin evolution, that the observed relative spindown of asteroids approximately 100 km diameter is likely to be the result of the angular momentum splash effect.

UV Spectroscopy of Metallic Asteroid (16) Psyche

NASA Astrophysics Data System (ADS)

Cunningham, N. J.; Becker, T. M.; Retherford, K. D.; Roth, L.; Feaga, L. M.; Wahlund, J.-E.; Elkins-Tanton, L. T.

2017-09-01

Asteroid (16) Psyche is the largest M-type asteroid, and the planned destination of the NASA Discovery mission Psyche and the proposed ESA M5 mission Heavy Metal. Psyche is considered to be the exposed core of a differentiated asteroid, whose mantle has been stripped by collisions; but other histories have been proposed. We observed Psyche with the Space Telescope Imaging Spectrograph (STIS) and Cosmic Origins Spectrograph (COS) aboard the Hubble Space Telescope, to obtain a full ultraviolet (UV) spectrum of both of Psyche's hemispheres. We seek to test three possible scenarios for Psyche's origin: Is Psyche the exposed core of a differentiated asteroid? Is it an asteroid with high olivine content that has been space-weathered? Or did Psyche accrete as-is in a highly-reducing environment early in the history of the solar system? We will present the UV spectra and their implications for Psyche's history.

A Re-examination of the Lightcurves for Seven Hungaria Asteroids

NASA Astrophysics Data System (ADS)

Warner, Brian D.; Stephens, Robert, D.; Harris, Alan W.; Pravec, Petr

2009-10-01

During the course of a study of long period asteroids (f < 1/d) within the Hungaria asteroid population, the lightcurves for seven asteroids were re-examined using updated software and techniques. Several were found to have significantly different periods from those previously reported by two of the authors (Warner and Stephens). The most significant change was 2074 Shoemaker, which was initially reported to have a period of 57 h but now appears to be a binary asteroid with a primary period of 2.5328 ± 0.0004 h and a possible orbital period of 55.52 ± 0.01 h. The other asteroids that were re-examined were 1919 Clemence, 3043 San Diego, 3353 Jarvis, 4142 Dersu-Uzala, (20232) 1997 YK, and (101549) 1998 YY2. The reexamination showed once again the importance of placing data on at least an internal system to achieve accurate night-to-night calibrations.

Radar observations of near-Earth asteroids from Arecibo Observatory

NASA Astrophysics Data System (ADS)

Rivera-Valentin, Edgard G.; Taylor, Patrick A.; Rodriguez-Ford, Linda A.; Zambrano Marin, Luisa Fernanda; Virkki, Anne; Aponte Hernandez, Betzaida

2016-10-01

The Arecibo S-Band (2.38 GHz, 12.6 cm, 1 MW) planetary radar system at the 305-m William E. Gordon Telescope in Arecibo, Puerto Rico is the most active and most sensitive planetary radar facility in the world. Since October 2015, we have detected 56 near-Earth asteroids, of which 17 are classified as potentially hazardous to Earth and 22 are compliant with the Near-Earth Object Human Space Flight Accessible Target Study (NHATS) as possible future robotic- or human-mission destinations. We will present a sampling of the asteroid zoo observed by the Arecibo radar since the 2015 DPS meeting. This includes press-noted asteroids 2015 TB145, the so-called "Great Pumpkin", and 2003 SD220, the so-called "Christmas Eve asteroid".

Mosaic of CCDs to Survey for Asteroids and Comets

NASA Technical Reports Server (NTRS)

McMillan, Robert S.

2002-01-01

Spacewatch searches for asteroids and comets ranging in location from near-Earth space to regions beyond the orbit of Neptune. We are studying Earth-approaching asteroids, main belt asteroids, comets, Centaurs, and TNOs, as well as the interrelationships of these classes and their bearing on the origin and evolution of the solar system. Spacewatch is described at http://www. lpl. arizona. edu/spacewatch/index.html. The Spacewatch Project has been discovering Earth-approaching asteroids (EAs) steadily and has used the results aggressively to estimate the statistical properties of the EA population. This grant funded Spacewatch to develop and implement a mosaic of CCD imaging detectors for the 0.9-m telescope, to increase that telescope's rate of coverage of sky area while preserving its limiting magnitude.

Flyght Dynamics of Artificial Satellite of the Minor Asteroid

NASA Astrophysics Data System (ADS)

Zakharov, Alexander; Eismont, Natan; Ledkov, Anton; Simonov, Alexander; Pol, Vadim

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.

The OSIRIS-REx Asteroid Sample Return Mission

NASA Technical Reports Server (NTRS)

Beshore, Edward; Lauretta, Dante; Boynton, William; Shinohara, Chriss; Sutter, Brian; Everett, David; Gal-Edd, Jonathan S.; Mink, Ronald G.; Moreau, Michael; Dworkin, Jason

2015-01-01

Interpretation, Resource Identification, Security, Regolith EXplorer) spacecraft will depart for asteroid (101955) Bennu, and when it does, humanity will turn an important corner in the exploration of the Solar System. After arriving at the asteroid in the Fall of 2018, it will undertake a program of observations designed to select a site suitable for retrieving a sample that will be returned to the Earth in 2023..

Trace elements record complex histories in diogenites

NASA Astrophysics Data System (ADS)

Balta, J. B.; Beck, A. W.; McSween, H. Y.

2012-12-01

Diogenite meteorites are cumulate rocks composed mostly of orthopyroxene and chemically linked to eucrites (basaltic) and howardites (brecciated mixtures of diogenites and eucrites). Together, they represent the largest single family of achondrite meteorites delivered to Earth, and have been spectrally linked to the asteroid 4 Vesta, the largest remaining basaltic protoplanet. However, this spectral link is non-unique as many basaltic asteroids likely formed and were destroyed in the early solar system. Recent work suggested that Vesta may be an unlikely parent body for the diogenites based on correlations between trace elements and short-lived isotope decay products, which would be unlikely to survive on a body as large as Vesta due to its long cooling history [1]. Recent analyses of terrestrial and martian olivines have demonstrated that trace element spatial distributions can preserve evidence of their crystallization history even when major elements have been homogenized [2]. We have mapped minor elements including Cr, Al, and Ti in seemingly homogeneous diogenite orthopyroxenes and found a variety of previously unobserved textures. The pyroxenes in one sample (GRA 98108) are seemingly large grains of variable shapes and sizes, but the trace elements reveal internal grain boundaries between roughly-equal sized original subgrains, with equilibrated metamorphic triple junctions between them and trace element depletions at the boundaries. These trends suggest extraction of trace elements by a magma along those relict grain boundaries during a reheating event. Two other samples show evidence of fracturing and annealing, with trace element mobility within grains. One sample appears to have remained a closed system during annealing (MET 01084), while the other has interacted with a fluid or magma to move elements along annealed cracks (LEW 88679). These relict features establish that the history of diogenite pyroxenes is more complex than their homogeneous major element compositions imply. Many trace element analyses are performed using either bulk rock techniques or spot analyses, and these maps suggest those types of analyses likely sample variable trace element abundances even within otherwise homogeneous grains, rendering their results difficult to interpret. Consequently, the correlation discussed previously between trace elements and short lived isotopes has likely been impacted by post-magmatic alteration and cannot solely be used to argue that HED's cannot be derived from Vesta. Furthermore, these maps strengthen the HED-Vesta link by suggesting that the diogenites underwent an extended history of cooling, reheating, partial melting, impact fragmentation, fluid/melt migration, and finally re-annealing. These complicated steps are particularly noteworthy as the pyroxene cumulate layer on the asteroid Vesta should lie beneath the eucritic crust, implying that early impacts were able to penetrate that crust and affect the diogenite layers early in Vesta's history, most likely while the asteroid was still hot enough to allow for annealing and regrowth of fractured grains. [1] Schiller et al. (2011) [2] Milman-Barris et al. (2008)

An Overview of Advanced Concepts for Launch

DTIC Science & Technology

2012-02-09

Loads, System. --- Space Platforms Unfeasible. --- Space Elevator Materials, O, µmeteoroids, weather, vibrations.. Asteroid Mining Breakthrough...Unfeasible. --- Space Elevator Materials, O, µmeteoroids, weather, vibrations.. Asteroid Mining Breakthrough Physics No known feasible concepts

Estimating Mass Parameters of Doubly Synchronous Binary Asteroids

NASA Astrophysics Data System (ADS)

Davis, Alex; Scheeres, Daniel J.

2017-10-01

The non-spherical mass distributions of binary asteroid systems lead to coupled mutual gravitational forces and torques. Observations of the coupled attitude and orbital dynamics can be leveraged to provide information about the mass parameters of the binary system. The full 3-dimensional motion has 9 degrees of freedom, and coupled dynamics require the use of numerical investigation only. In the current study we simplify the system to a planar ellipsoid-ellipsoid binary system in a doubly synchronous orbit. Three modes are identified for the system, which has 4 degrees of freedom, with one degree of freedom corresponding to an ignorable coordinate. The three modes correspond to the three major librational modes of the system when it is in a doubly synchronous orbit. The linearized periods of each mode are a function of the mass parameters of the two asteroids, enabling measurement of these parameters based on observations of the librational motion. Here we implement estimation techniques to evaluate the capabilities of this mass measurement method. We apply this methodology to the Trojan binary asteroid system 617 Patroclus and Menoetius (1906 VY), the final flyby target of the recently announced LUCY Discovery mission. This system is of interest because a stellar occultation campaign of the Patroclus and Menoetius system has suggested that the asteroids are similarly sized oblate ellipsoids moving in a doubly-synchronous orbit, making the system an ideal test for this investigation. A number of missed observations during the campaign also suggested the possibility of a crater on the southern limb of Menoetius, the presence of which could be evaluated by our mass estimation method. This presentation will review the methodology and potential accuracy of our approach in addition to evaluating how the dynamical coupling can be used to help understand light curve and stellar occultation observations for librating binary systems.

A Newborn Asteroid Family of Likely Rotational Origin Harboring a Doubly-Synchronous Binary

NASA Astrophysics Data System (ADS)

Drahus, Michal; Waniak, Waclaw

2016-10-01

From the total number of about twenty active asteroids identified to date, one of the most intriguing is P/2012 F5. The 2-km sized object has a short rotation period of 3.24 hr - the shortest known among main-belt active asteroids and comets - and is trailed by several fragments recently separated from the main nucleus (Drahus et al. 2015, ApJL 802, L8). Our extensive observations with Hubble in late 2015 and early 2016 have revealed that the fragments are real and stable "baby asteroids", still cocooned in their birth dust trail. Consequently, P/2012 F5 is the first known asteroid family forming in the present-day epoch. Given the rapid spin of the main nucleus, the system is also the best candidate for the first "rotational" asteroid family originating from rotational fission (as opposed to the long-known "collisional" families), extending the recently identified class of asteroid pairs (Pravec et al. 2010, Nature 466, 1085). Furthermore, the HST data allowed us to measure a light curve of the brightest fragment of P/2012 F5, several magnitudes fainter than the main nucleus. The light curve has all the characteristics of a close binary with significantly elongated, roughly equal sized components, having equal rotation and orbital periods of about 9 hr. The existence of a doubly-synchronous binary in an ultra-young asteroid family is seemingly inconsistent with the established "slow" binary formation path, in which YORP torques first lead to rotational fission and then tides lead to synchronization (Jacobson & Scheeres 2011, Icarus 214, 161). Instead, we believe that the object fissioned while orbiting the main nucleus and drawing its angular momentum, and was subsequently ejected from the system as a finished doubly-synchronous binary. This scenario is consistent with computer simulations in that the timescales for secondary fission and ejection from the system are indeed very short (Jacobson & Scheeres 2011, Icarus 214, 161). But the empirical evidence that fissioned secondaries can escape as doubly-synchronous binaries came as a surprise, so we seem to have accidentally identified a new, "rapid" formation path of such systems, not yet accounted for by the prevailing theory.

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

Bhattacharya, B.; Helou, G.; Noriega-Crespo, A.

The Spitzer Space Telescope routinely detects asteroids in astrophysical observations near the ecliptic plane. For the galactic or extragalactic astronomer, these solar system bodies can introduce appreciable uncertainty into the source identification process. We discuss an infrared color discrimination tool that may be used to distinguish between solar system objects and extrasolar sources. We employ four Spitzer Legacy data sets, the First Look Survey-Ecliptic Plane Component (FLS-EPC), SCOSMOS, SWIRE, and GOODS. We use the Standard Thermal Model to derive FLS-EPC main belt asteroid (MBA) diameters of 1-4 km for the numbered asteroids in our sample and note that several ofmore » our solar system sources may have fainter absolute magnitude values than previously thought. A number of the MBAs are detected at flux densities as low as a few tens of {mu}Jy at 3.6 {mu}m. As the FLS-EPC provides the only 3.6-24.0 {mu}m observations of individual asteroids to date, we are able to use this data set to carry out a detailed study of asteroid color in comparison to astrophysical sources observed by SCOSMOS, SWIRE, and GOODS. Both SCOSMOS and SWIRE have identified a significant number of asteroids in their data, and we investigate the effectiveness of using relative color to distinguish between asteroids and background objects. We find a notable difference in color in the IRAC 3.6-8.0 mm and MIPS 24 {mu}m bands between the majority of MBAs, stars, galaxies, and active galactic nuclei, though this variation is less significant when comparing fluxes in individual bands. We find median colors for the FLS-EPC asteroids to be [F(5.8/3.6), F(8.0/4.5), F(24/8)] = (4.9 {+-} 1.8, 8.9 {+-} 7.4, 6.4 {+-} 2.3). Finally, we consider the utility of this technique for other mid-infrared observations that are sensitive to near-Earth objects, MBAs, and trans-Neptunian objects. We consider the potential of using color to differentiate between solar system and background sources for several space-based observatories, including Warm Spitzer, Herschel, and WISE.« less

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.

Contextual Student Learning through Authentic Asteroid Research Projects using a Robotic Telescope Network

NASA Astrophysics Data System (ADS)

Hoette, Vivian L.; Puckett, Andrew W.; Linder, Tyler R.; Heatherly, Sue Ann; Rector, Travis A.; Haislip, Joshua B.; Meredith, Kate; Caughey, Austin L.; Brown, Johnny E.; McCarty, Cameron B.; Whitmore, Kevin T.

2015-11-01

Skynet is a worldwide robotic telescope network operated by the University of North Carolina at Chapel Hill with active observing sites on 3 continents. The queue-based observation request system is simple enough to be used by middle school students, but powerful enough to supply data for research scientists. The Skynet Junior Scholars program, funded by the NSF, has teamed up with professional astronomers to engage students from middle school to undergraduates in authentic research projects, from target selection through image analysis and publication of results. Asteroid research is a particularly fruitful area for youth collaboration that reinforces STEM education standards and can allow students to make real contributions to scientific knowledge, e.g., orbit refinement through astrometric submissions to the Minor Planet Center. We have created a set of projects for youth to: 1. Image an asteroid, make a movie, and post it to a gallery; 2. Measure the asteroid’s apparent motion using the Afterglow online image processor; and 3. Image asteroids from two or more telescopes simultaneously to demonstrate parallax. The apparent motion and parallax projects allow students to estimate the distance to their asteroid, as if they were the discoverer of a brand new object in the solar system. Older students may take on advanced projects, such as analyzing uncertainties in asteroid orbital parameters; studying impact probabilities of known objects; observing time-sensitive targets such as Near Earth Asteroids; and even discovering brand new objects in the solar system.Images are acquired from among seven Skynet telescopes in North Carolina, California, Wisconsin, Canada, Australia, and Chile, as well as collaborating observatories such as WestRock in Columbus, Georgia; Stone Edge in El Verano, California; and Astronomical Research Institute in Westfield, Illinois.

Photometry of Main Belt and Trojan asteroids with K2

NASA Astrophysics Data System (ADS)

Szabó, Gyula; Kiss, Csaba; Pal, Andras; Szabo, Robert

2016-10-01

Due to the failure of the second reaction wheel, a new mission was conceived for the otherwise healthy Kepler space telescope. In the course of the K2 Mission, the telescope is staring at the plane of the Ecliptic, hence thousands of Solar System bodies cross the K2 fields, usually causing extra noise in the highly accurate photometric data.We could measure the first continuous asteroid light curves, covering several days wthout interruption, that has been unprecedented to date. We studied the K2 superstamps covering the M35 and Neptune/Nereid fields observed in the long cadence (29.4-min sampling) mode. Asteroid light curves are generated by applying elongated apertures. We investigated the photometric precision that the K2 Mission can deliver on moving Solar System bodies, and determined the first uninterrupted optical light curves of main-belt and Trojan asteroids. We use thed Lomb-Scargle method to find periodicities due to rotation.We derived K2 light curves of 924 main-belt asteroids in the M35 field, and 96 in the path of Neptune and Nereid. Due to the faintness of the asteroids and the high density of stars in the M35 field, 4.0% of the asteroids with at least 12 data points show clear periodicities or trend signalling a long rotational period, as opposed to 15.9% in the less crowded Neptune field. We found that the duty cycle of the observations had to reach ˜ 60% in order to successfully recover rotational periods.The derived period-amplitude diagram is consistent to the known distribution of Main Belt asteroids. For Trojan asteroids, the contribution of our 56 objects with newly determined precise period and amplitude is in the order of all previously known asteroids. The comparison with earth-based determinations showed a previous bias toward short periods and has also proven that asteroid periods >20 hour can be unreliable in a few cases because of daylight time and diurnal calibrations. These biases are avoided from the space. We present an unbiased sample of rotation periods and identify a higher rate of slow rotators. We also found multiple periods of large asteroids that has not been observed earlier and still needs explanation.

Numerical Simulations of Granular Physics in the Solar System

NASA Astrophysics Data System (ADS)

Ballouz, Ronald

2017-08-01

Granular physics is a sub-discipline of physics that attempts to combine principles that have been developed for both solid-state physics and engineering (such as soil mechanics) with fluid dynamics in order to formulate a coherent theory for the description of granular materials, which are found in both terrestrial (e.g., earthquakes, landslides, and pharmaceuticals) and extra-terrestrial settings (e.g., asteroids surfaces, asteroid interiors, and planetary ring systems). In the case of our solar system, the growth of this sub-discipline has been key in helping to interpret the formation, structure, and evolution of both asteroids and planetary rings. It is difficult to develop a deterministic theory for granular materials due to the fact that granular systems are composed of a large number of elements that interact through a non-linear combination of various forces (mechanical, gravitational, and electrostatic, for example) leading to a high degree of stochasticity. Hence, we study these environments using an N-body code, pkdgrav, that is able to simulate the gravitational, collisional, and cohesive interactions of grains. Using pkdgrav, I have studied the size segregation on asteroid surfaces due to seismic shaking (the Brazil-nut effect), the interaction of the OSIRIS-REx asteroid sample-return mission sampling head, TAGSAM, with the surface of the asteroid Bennu, the collisional disruptions of rubble-pile asteroids, and the formation of structure in Saturn's rings. In all of these scenarios, I have found that the evolution of a granular system depends sensitively on the intrinsic properties of the individual grains (size, shape, sand surface roughness). For example, through our simulations, we have been able to determine relationships between regolith properties and the amount of surface penetration a spacecraft achieves upon landing. Furthermore, we have demonstrated that this relationship also depends on the strength of the local gravity. By comparing our numerical results to laboratory experiments and observations by spacecraft we can begin to understand which microscopic properties (i.e., grain properties) control the macroscopic properties of the system. For example, we can compare the mechanical response of a spacecraft to landing or Cassini observations of Saturn's ring to understand how the penetration depth of a spacecraft or the complex optical depth structure of a ring system depends on the size and surface properties of the grains in those systems.

Radar Imagery of Asteroid 2014 JO25

NASA Image and Video Library

2017-04-19

This composite of 30 images of asteroid 2014 JO25 was generated with radar data collected using NASA Goldstone Solar System Radar in California Mojave Desert. https://photojournal.jpl.nasa.gov/catalog/PIA21594

Tools for Asteroid Regolith Operations

NASA Technical Reports Server (NTRS)

Mueller, Robert P.; Calle, Carlos I.; Mantovani, James G.

2013-01-01

This RFI response is targeting Area 5. Crew Systems for Asteroid Exploration: concepts for lightweight and low volume robotic and extra-vehicular activity (EVA) systems, such as space suits, tools, translation aids, stowage containers, and other equipment.The NASA KSC Surface Systems Office, Granular Mechanics and Regolith Operations (GMRO) Lab and the Electrostatics Surface Physics Lab (ESPL) are dedicated to developing technologies for operating in regolith environments on target body surfaces. We have identified two technologies in our current portfolio that are highly relevant and useful for crews that will visit a re-directed asteroid in Cis-Lunar Space. Both technologies are at a high TRL of 56 and could be rapidly implemented in time for an ARM mission in this decade.

Qualitative and quantitative behaviour of planetary systems; Proceedings of the 3rd Alexander von Humboldt Colloquium on Celestial Mechanics, Ramsau, Austria, Mar. 29-Apr. 4, 1992

NASA Astrophysics Data System (ADS)

Dvorak, R.; Henrard, J.

1993-06-01

Topics addressed include planetary theories, the Sitnikov problem, asteroids, resonance, general dynamical systems, and chaos and stability. Particular attention is given to recent progress in the theory and application of symplectic integrators, a computer-aided analysis of the Sitnikov problem, the chaotic behavior of trajectories for the asteroidal resonances, and the resonant motion in the restricted three-body problem. Also discussed are the second order long-period motion of Hyperion, meteorites from the asteroid 6 Hebe, and least squares parameter estimation in chaotic differential equations.

Power Supply for a Manned International Asteroid Mission

NASA Technical Reports Server (NTRS)

Weingartner, Stefan; Nahra, Henry K.; Kohout, Lisa L.; Larin, Max

1991-01-01

A feasibility study considering the exploitation of a near Earth asteroid was performed. The power requirements and proposed power systems for the crew vehicle, cargo vehicles, mining and processing equipment are described. A photovoltaic power system was selected to meet the 52.1 kWe and the 3.9 kWe power requirements of the crew and cargo vehicles, respectively. A nuclear power plant using a thermodynamic Rankine cycle with a total mass of 62.1 tons was chosen to provide the 7.225 MWe and the 5.5 MWth required for the mining and processing activities at the asteroid.

On the metal-rich surfaces of (16) Psyche and other M-type asteroids from interferometric observations in the thermal infrared

NASA Astrophysics Data System (ADS)

Delbo, Marco; Matter, A.; Gundlach, B.; Blum, J.

2013-10-01

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.

VESTOIDS, PART II: THE BASALTIC NATURE AND HED METEORITE ANALOGS FOR EIGHT V{sub p}-TYPE ASTEROIDS AND THEIR ASSOCIATIONS WITH (4) VESTA

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

Hardersen, Paul S.; Reddy, Vishnu; Roberts, Rachel, E-mail: Hardersen@space.edu

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

Investigating the surface and subsurface properties of the Didymos binary asteroid with a landed CubeSat

NASA Astrophysics Data System (ADS)

Murdoch, Naomi; Cadu, Alexandre; Mimoun, David; Karatekin, Ozgur; Garcia, Raphael; Carrasco, José; Garcia de Quiros, Javier; Vasseur, Hugues; Ritter, Birgit; Eubanks, Marshall; Radley, Charles; Dehant, Veronique

2016-04-01

Despite the successes of recent space missions (e.g., Cheng et al., 1997; Fujiwara et al., 2006), there is still no clear understanding of the asteroid internal structure(s). Depending on their size, evolution and physical properties, many different asteroid internal structure models have been suggested from completely cohesive bodies, through to rubble pile objects. The Asteroid Geophysical Explorer (AGEX), a COPINS payload selected by ESA*, will land geophysical instrument packages on the surface of Didymoon; the secondary object in the (65803) Didymos (1996 GT) binary system (Karatekin et al 2016). The instruments will characterize the asteroid surface mechanical properties and probe, for the first time, the sub-surface structure of an asteroid. AGEX will be deployed from AIM on a ballistic transfer to the asteroid surface, several days before the MASCOT-2 package. We expect that AGEX will bounce multiple times before coming to rest on the surface of the asteroid thus providing a unique opportunity to study the asteroid surface properties, perhaps at several locations, using accelerometers. Once stationary, the seismological surface-monitoring phase, using a three-axis set of geophones, can begin. The high speed DART impact will be a major seismic source on Didymoon. However, the seismic payload may also be able to perform seismological investigations using natural seismic sources such as micrometeoroid impacts (e.g., Garcia et al., 2015), thermal cracks (e.g., Delbo et al., 2014), internal quakes due to tidal forces (e.g., Richardson et al. 1998) and other geophysical processes (see Murdoch et al., 2015). We will present the expected signal characteristics of the landing and also of the natural seismic sources that may occur on Didymoon. An understanding of the amplitude and frequency content of such signals is necessary in order to design the optimal geophysical payload for small body exploration using a CubeSat platform. [1.] Cheng, A. et al., Journal of Geophysical Research, 102, E10 (1997) [2.] Delbo, M., et al., Nature, 508, 233-236 (2014) [3.] Fujiwara, A. et al., Science 312, 1330 (2006) [4.] Garcia, R. F. et al., Icarus, 253, 159-168 (2015) [5.] Murdoch, N. et al., ASTEROIDS IV, University of Arizona Press Space Science Series, edited by P. Michel, F. DeMeo and W. Bottke, (2015) [6.] Richardson, D.C. et al., Icarus, 134, 47-79 (1998) [7.] Karatekin et al., The Asteroid Geophysical Explorer (AGEX); Proposal to explore the Didymos System using Cubesats, EGU (2016) *http://www.esa.int/Our_Activities/Space_Engineering_Technology/Asteroid_Impact_Mission/ CubeSat_companions_for_ESA_s_asteroid_mission

Application of Close Encounters in Determining the Masses of Asteroids

NASA Astrophysics Data System (ADS)

Tang, H. J.; Li, F.; Fu, Y. N.

2017-11-01

Asteroids are important part of the solar system. So far, the number of known asteroids is more than seven hundred thousand, and the total number is probably more than one million. Among many events of encounters among asteroids, those very close ones can be used to improve the precision of the masses of asteroids. To achieve this, it's necessary to search for the latter events in advance by making an accurate assessment of the effectiveness of an encounter in the mass determination. In this context, the previous dynamical models and assessing indicators are not precise enough. By using a more realistic dynamical model and introducing a properly defined Signal-to-Noise ratio, we are able to estimate the precision of the mass determination based on observations made from the Earth. Moreover, the best observation time span can be quantitatively given, which is useful in collecting observational data and planning further observations. We search systematically for the useful asteroid encounters involving one of the 773 massive asteroids with equivalent diameter larger than 50 km, for which the searched time span is from the year 2000 to 2030.

Logistics Needs for Potential Deep Space Mission Scenarios Post Asteroid Crewed Mission

NASA Technical Reports Server (NTRS)

Lopez, Pedro, Jr.

2015-01-01

A deep-space mission has been proposed to identify and redirect an asteroid to a distant retrograde orbit around the moon, and explore it by sending a crew using the Space Launch System and the Orion spacecraft. The Asteroid Redirect Crewed Mission (ARCM), which represents the third segment of the Asteroid Redirect Mission (ARM), could be performed on EM-3 or EM-4 depending on asteroid return date. Recent NASA studies have raised questions on how we could progress from current Human Space Flight (HSF) efforts to longer term human exploration of Mars. This paper will describe the benefits of execution of the ARM as the initial stepping stone towards Mars exploration, and how the capabilities required to send humans to Mars could be built upon those developed for the asteroid mission. A series of potential interim missions aimed at developing such capabilities will be described, and the feasibility of such mission manifest will be discussed. Options for the asteroid crewed mission will also be addressed, including crew size and mission duration.

Trajectory of asteroid 2017 SB20 within the CRTBP

NASA Astrophysics Data System (ADS)

Tiwary, Rishikesh Dutta; Kushvah, Badam Singh; Ishwar, Bhola

2018-06-01

Regular monitoring the trajectory of asteroids to a future time is a necessity, because the variety of known probably unsafe near-Earth asteroids are increasing. The analysis is perform to avoid any incident or whether they would have a further future threat to the Earth or not. Recently a new Near Earth Asteroid (2017 SB20) has been observed to cross the Earth orbit. In view of this we obtain the trajectory of Asteroid in the circular restricted three body problem with radiation pressure and oblateness. We examine nature of Asteroid's orbit with Lyapunov Characteristic Exponents (LCEs) over a finite intervals of time. LCE of the system confirms that the motion of asteroid is chaotic in nature. With the effect of radiation pressure and oblateness the length of curve varies in both the planes. Oblateness factor is found to be more perturbative than radiation pressure. To see the precision of result obtain from numerical integration we show the error propagation and the numerical stability is assured around the singularity by applying regularized equations of motion for precise long-term study.

Spitzer IRS Spectra of Basaltic Asteroids: Preliminary Results

NASA Technical Reports Server (NTRS)

Lim, Lucy F.; Emery, Joshua P.; Moskovitz, Nick; Stewart, Heather; Marchis, Frank

2008-01-01

We present preliminary results of a Spitzer program to observe the 5.2--38 micron spectra of small basaltic asteroids using the Spitzer IRS (Infrared Spectrograph). Our targets include members of the dynamical family of the unique large differentiated asteroid 4 Vesta ("Vestoids"), four outer-main-belt basaltic asteroids whose orbits exclude them from originating on 4 Vesta, and the basaltic near-Earth asteroid (NEA) 4055 Magellan. We will compare the compositions and thermophysical properties of the non-Vestoid objects with those of the dynamical vestoids to provide insight on the extent of metal-silicate differentiation on planetsimals during the epoch of planet formation in the early Solar System. As of this writing, spectra of asteroids 10537 (1991 RY16) and 2763 Jeans have been returned. Analysis of these data are ongolng. Observations of 956 Elisa, 2653 Principia, 4215 Kamo, 7472 Kumakiri, and 1459 Magnya have been scheduled and are expected to be available by the time of the DPS meeting. NIR spectra and lightcurves o f the target asteroids are also being observed in support of this program.

AN ASTEROID BELT INTERPRETATION FOR THE TIMING VARIATIONS OF THE MILLISECOND PULSAR B1937+21

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

Shannon, R. M.; Cordes, J. M.; Metcalfe, T. S.

Pulsar timing observations have revealed companions to neutron stars that include other neutron stars, white dwarfs, main-sequence stars, and planets. We demonstrate that the correlated and apparently stochastic residual times of arrival from the millisecond pulsar B1937+21 are consistent with the signature of an asteroid belt having a total mass {approx}< 0.05 M{sub Circled-Plus }. Unlike the solar system's asteroid belt, the best fit pulsar asteroid belt extends over a wide range of radii, consistent with the absence of any shepherding companions. We suggest that any pulsar that has undergone accretion-driven spin-up and subsequently evaporated its companion may harbor orbitingmore » asteroid mass objects. The resulting timing variations may fundamentally limit the timing precision of some of the other millisecond pulsars. Observational tests of the asteroid belt model include identifying periodicities from individual asteroids, which are difficult; testing for statistical stationarity, which becomes possible when observations are conducted over a longer observing span; and searching for reflected radio emission.« less

The great asteroid nomenclature controversy of 1801

NASA Technical Reports Server (NTRS)

Cunningham, Clifford J.

1992-01-01

With the almost complete neglect of 19th century asteroid research by professional historians of science, it is scarcely surprising that great gaps exist in our knowledge of that important field. This paper focuses on issue of naming the first asteroid. This seemingly innocuous issue assumed great importance because many believed the object discovered by Giuseppe Piazzi at Palermo Observatory to be the eighth primary planet of the solar system.

Near-Earth Asteroid Retrieval Mission (ARM) Study

NASA Technical Reports Server (NTRS)

Brophy, John R.; Muirhead, Brian

2013-01-01

The Asteroid Redirect Mission (ARM) concept brings together the capabilities of the science, technology, and the human exploration communities on a grand challenge combining robotic and human space exploration beyond low Earth orbit. This paper addresses the key aspects of this concept and the options studied to assess its technical feasibility. Included are evaluations of the expected number of potential targets, their expected discovery rate, the necessity to adequately characterize candidate mission targets, the process to capture a non-cooperative asteroid in deep space, and the power and propulsion technology required for transportation back to the Earth-Moon system. Viable options for spacecraft and mission designs are developed. Orbits for storing the retrieved asteroid that are stable for more than a hundred years, yet allow for human exploration and commercial utilization of a redirected asteroid, are identified. The study concludes that the key aspects of finding, capturing and redirecting an entire small, near-Earth asteroid to the Earth-Moon system by the first half of the next decade are technically feasible. The study was conducted from January 2013 through March 2013 by the Jet Propulsion Laboratory (JPL) in collaboration with Glenn Research Center (GRC), Johnson Space Center (JSC), Langley Research Center (LaRC), and Marshall Space Flight Center (MSFC).

Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results

NASA Astrophysics Data System (ADS)

Vereš, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; Chastel, Serge; Wainscoat, Richard J.; Burgett, William S.; Chambers, Kenneth C.; Flewelling, Heather; Kaiser, Nick; Magnier, Eugen A.; Morgan, Jeff S.; Price, Paul A.; Tonry, John L.; Waters, Christopher

2015-11-01

We present the results of a Monte Carlo technique to calculate the absolute magnitudes (H) and slope parameters (G) of ∼240,000 asteroids observed by the Pan-STARRS1 telescope during the first 15 months of its 3-year all-sky survey mission. The system's exquisite photometry with photometric errors ≲ 0.04mag , and well-defined filter and photometric system, allowed us to derive accurate H and G even with a limited number of observations and restricted range in phase angles. Our Monte Carlo method simulates each asteroid's rotation period, amplitude and color to derive the most-likely H and G, but its major advantage is in estimating realistic statistical + systematic uncertainties and errors on each parameter. The method was tested by comparison with the well-established and accurate results for about 500 asteroids provided by Pravec et al. (Pravec, P. et al. [2012]. Icarus 221, 365-387) and then applied to determining H and G for the Pan-STARRS1 asteroids using both the Muinonen et al. (Muinonen, K. et al. [2010]. Icarus 209, 542-555) and Bowell et al. (Bowell, E. et al. [1989]. Asteroids III, Chapter Application of Photometric Models to Asteroids. University of Arizona Press, pp. 524-555) phase functions. Our results confirm the bias in MPC photometry discovered by Jurić et al. (Jurić, M. et al. [2002]. Astrophys. J. 124, 1776-1787).

Rotational properties of the Maria asteroid family

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

Kim, M.-J.; Byun, Y.-I.; Choi, Y.-J.

2014-03-01

The Maria family is regarded as an old-type (∼3 ± 1 Gyr) asteroid family that has experienced substantial collisional and dynamical evolution in the main belt. It is located near the 3:1 Jupiter mean-motion resonance area that supplies near-Earth asteroids to the inner solar system. We carried out observations of Maria family asteroids during 134 nights from 2008 July to 2013 May and derived synodic rotational periods for 51 objects, including newly obtained periods of 34 asteroids. We found that there is a significant excess of fast and slow rotators in the observed rotation rate distribution. The one-sample Kolmogorov-Smirnov testmore » confirms that the spin rate distribution is not consistent with a Maxwellian at a 92% confidence level. From correlations among rotational periods, amplitudes of light curves, and sizes, we conclude that the rotational properties of Maria family asteroids have been changed considerably by non-gravitational forces such as the YORP effect. Using a light-curve inversion method, we successfully determined the pole orientations for 13 Maria members and found an excess of prograde versus retrograde spins with a ratio (N{sub p} /N{sub r} ) of 3. This implies that the retrograde rotators could have been ejected by the 3:1 resonance into the inner solar system since the formation of the Maria family. We estimate that approximately 37-75 Maria family asteroids larger than 1 km have entered near-Earth space every 100 Myr.« less

The asteroid rendezvous spacecraft. An adaptation study of TIROS/DMSP technology

NASA Technical Reports Server (NTRS)

1982-01-01

The feasibility of using the TIROS/DMSP Earth orbiting meteorological satellite in application to a near Earth asteroid rendezvous mission. System and subsystems analysis was carried out to develop a configuration of the spacecraft suitable for this mission. Mission analysis studies were also done and maneuver/rendezvous scenarios developed for baseline missions to both Anteros and Eros. The fact that the Asteroid mission is the most complex of the Pioneer class missions currently under consideration notwithstanding, the basic conclusion very strongly supports the suitability of the basic TIROS bus for this mission in all systems and subsystems areas, including science accommodation. Further, the modifications which are required due to the unique mission are very low risk and can be accomplished readily. The key issue is that in virtually every key subsystem, the demands of the Asteroid mission are a subset of the basic meteorological satellite mission. This allows a relatively simple reconfiguration to be accomplished without a major system redesign.

Lunar and Planetary Science XXXV: Origin of Planetary Systems

NASA Technical Reports Server (NTRS)

2004-01-01

The session "Origin of Planetary Systems" included the following reports: (12753) Povenmire - Standard Comparison Small Main Belt Asteroid?; Gravitational Frequencies of Extra-Solar Planets; 'Jumping Jupiters' in Binary Star Systems; Hermes, Asteroid 2002 SY50 and the Northern Cetids - No Link Found!; What Kind of Accretion Model is Required for the Solar System; and Use of an Orbital Phase Curve of Extrasolar Planet for Specification of its Mass.

Modeling and experimental validation of sawing based lander anchoring and sampling methods for asteroid exploration

NASA Astrophysics Data System (ADS)

Zhang, Jun; Dong, Chengcheng; Zhang, Hui; Li, Song; Song, Aiguo

2018-05-01

This paper presents a novel lander anchoring system based on sawing method for asteroid exploration. The system is composed of three robotic arms, three cutting discs, and a control system. The discs mounted at the end of the arms are able to penetrate into the rock surface of asteroids. After the discs cut into the rock surface, the self-locking function of the arms provides forces to fix the lander on the surface. Modeling, trajectory planning, simulations, mechanism design, and prototype fabrication of the anchoring system are discussed, respectively. The performances of the system are tested on different kinds of rocks, at different sawing angles, locations, and speeds. Results show that the system can cut 15 mm deep into granite rock in 180 s at sawing angle of 60°, with the average power of 58.41 W, and the "weight on bit" (WOB) of 8.637 N. The 7.8 kg anchoring system is capable of providing omni-directional anchoring forces, at least 225 N normal and 157 N tangent to the surface of the rock. The system has the advantages of low-weight, low energy consumption and balance forces, high anchoring efficiency and reliability, and could enable the lander to move and sample or assist astronauts and robots in walking and sampling on asteroids.

Distant asteroids and Chiron

NASA Technical Reports Server (NTRS)

French, Linda M.; Vilas, Faith; Hartmann, William K.; Tholen, David J.

1989-01-01

Knowledge of the physical properties of distant asteroids (a greater than 3.3 AU) has grown dramatically over the past five years, due to systematic compositional and lighcurve studies. Most of these objects have red, dark surfaces, and their spectra show a reddening in spectral slope with heliocentric distance, implying a change in surface composition. Trojans for which near-opposition phase curve information is available appear to show little or no opposition effect, unlike any other dark solar system objects. The lightcurve amplitudes of Trojan and Hilda asteroids imply significantly more elongated shapes for these groups than for main-belt asteroids of comparable size. These recent observations are reviewed in the context of their implications for the formationan and subsequent evolution of the distant asteroids, and their interrelations with the main belt, Chiron, and comets.

In-Situ Resource Utilization Experiment for the Asteroid Redirect Crewed Mission

NASA Astrophysics Data System (ADS)

Elliott, J.; Fries, M.; Love, S.; Sellar, R. G.; Voecks, G.; Wilson, D.

2015-10-01

The Asteroid Redirect Crewed Mission (ARCM) represents a unique opportunity to perform in-situ testing of concepts that could lead to full-scale exploitation of asteroids for their valuable resources [1]. This paper describes a concept for an astronautoperated "suitcase" experiment to would demonstrate asteroid volatile extraction using a solar-heated oven and integral cold trap in a configuration scalable to full-size asteroids. Conversion of liberated water into H2 and O2 products would also be demonstrated through an integral processing and storage unit. The plan also includes development of a local prospecting system consisting of a suit-mounted multi-spectral imager to aid the crew in choosing optimal samples, both for In-Situ Resource Utilization (ISRU) and for potential return to Earth.

Triple Helix Systems: An Analytical Framework for Innovation Policy and Practice in the Knowledge Society

ERIC Educational Resources Information Center

Ranga, Marina; Etzkowitz, Henry

2013-01-01

This paper introduces the concept of Triple Helix systems as an analytical construct that synthesizes the key features of university--industry--government (Triple Helix) interactions into an "innovation system" format, defined according to systems theory as a set of components, relationships and functions. Among the components of Triple…

On the Contribution of Asteroid Disruptions to the Interplanetary Dust Flux

NASA Astrophysics Data System (ADS)

Kehoe, T. J. J.; Kehoe, A. E.

2017-12-01

Recent modeling has shown the significant contribution of micron- to millimeter-sized particles released by the disruption of main-belt asteroids (MBAs) to the interplanetary dust particle (IDP) flux (e.g., Dermott et al., 2002; Nesvorný et al., 2003; Espy Kehoe et al., 2015). In this paper, we present the results of a study that indicates that the dust injected into the zodiacal cloud due to the catastrophic disruption of an asteroid is dominated by the release of its surface regolith particles. Our research suggests that disrupting a single asteroid with diameter O(100 km) will be enough to regenerate the entire zodiacal cloud. The breakup of smaller asteroids with diameters O(10 km) will likely produce more moderate, but still significant, changes in the dust environment of the inner solar system. As collisional disruptions of asteroids in this size range occur more frequently, it is important that we develop a better understanding of the injection of asteroidal material into the zodiacal cloud as a result of these type of events in order to determine the temporal evolution of the interplanetary dust flux. The results presented in this paper will lead to a better understanding of the threat to exploration activities due to the enhanced IDP flux resulting from the disruption of asteroidal regoliths. These findings can be employed to improve engineering models, for example, the NASA Meteoroid Engineering Model (MEM) that is widely utilized to assess the impact hazard to space hardware and activities in the inner solar system due to the natural meteoroid environment (McNamara et al., 2004). This is an important area of concern for current and future mission development purposes.

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.

Spacewatch Survey of the Solar System

NASA Technical Reports Server (NTRS)

McMillan, Robert S.

2000-01-01

The purpose of the Spacewatch project is to explore the various populations of small objects throughout the solar system. Statistics on all classes of small bodies are needed to infer their physical and dynamical evolution. More Earth Approachers need to be found to assess the impact hazard. (We have adopted the term "Earth Approacher", EA, to include all those asteroids, nuclei of extinct short period comets, and short period comets that can approach close to Earth. The adjective "near" carries potential confusion, as we have found in communicating with the media, that the objects are always near Earth, following it like a cloud.) Persistent and voluminous accumulation of astrometry of incidentally observed main belt asteroids MBAs will eventually permit the Minor Planet Center (MPQ to determine the orbits of large numbers (tens of thousands) of asteroids. Such a large body of information will ultimately allow better resolution of orbit classes and the determinations of luminosity functions of the various classes, Comet and asteroid recoveries are essential services to planetary astronomy. Statistics of objects in the outer solar system (Centaurs, scattered-disk objects, and Trans-Neptunian Objects; TNOs) ultimately will tell part of the story of solar system evolution. Spacewatch led the development of sky surveying by electronic means and has acted as a responsible interface to the media and general public on this discipline and on the issue of the hazard from impacts by asteroids and comets.

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.

A Shared Bombardment History

NASA Image and Video Library

2013-03-25

Studying meteorites from the asteroid Vesta helps scientists understand the event known as the lunar cataclysm, when a repositioning of the gas giant planets destabilized a portion of the asteroid belt and triggered a solar-system-wide bombardment.

Solar System Science with LSST

NASA Astrophysics Data System (ADS)

Jones, R. L.; Chesley, S. R.; Connolly, A. J.; Harris, A. W.; Ivezic, Z.; Knezevic, Z.; Kubica, J.; Milani, A.; Trilling, D. E.

2008-09-01

The Large Synoptic Survey Telescope (LSST) will provide a unique tool to study moving objects throughout the solar system, creating massive catalogs of Near Earth Objects (NEOs), asteroids, Trojans, TransNeptunian Objects (TNOs), comets and planetary satellites with well-measured orbits and high quality, multi-color photometry accurate to 0.005 magnitudes for the brightest objects. In the baseline LSST observing plan, back-to-back 15-second images will reach a limiting magnitude as faint as r=24.7 in each 9.6 square degree image, twice per night; a total of approximately 15,000 square degrees of the sky will be imaged in multiple filters every 3 nights. This time sampling will continue throughout each lunation, creating a huge database of observations. Fig. 1 Sky coverage of LSST over 10 years; separate panels for each of the 6 LSST filters. Color bars indicate number of observations in filter. The catalogs will include more than 80% of the potentially hazardous asteroids larger than 140m in diameter within the first 10 years of LSST operation, millions of main-belt asteroids and perhaps 20,000 Trans-Neptunian Objects. Objects with diameters as small as 100m in the Main Belt and <100km in the Kuiper Belt can be detected in individual images. Specialized `deep drilling' observing sequences will detect KBOs down to 10s of kilometers in diameter. Long period comets will be detected at larger distances than previously possible, constrainting models of the Oort cloud. With the large number of objects expected in the catalogs, it may be possible to observe a pristine comet start outgassing on its first journey into the inner solar system. By observing fields over a wide range of ecliptic longitudes and latitudes, including large separations from the ecliptic plane, not only will these catalogs greatly increase the numbers of known objects, the characterization of the inclination distributions of these populations will be much improved. Derivation of proper elements for main belt and Trojan asteroids will allow ever more resolution of asteroid families and their size-frequency distribution, as well as the study of the long-term dynamics of the individual asteroids and the asteroid belt as a whole. Fig. 2 Orbital parameters of Main Belt Asteroids, color-coded according to ugriz colors measured by SDSS. The figure to the left shows osculating elements, the figure to the right shows proper elements - note the asteroid families visible as clumps in parameter space [1]. By obtaining multi-color ugrizy data for a substantial fraction of objects, relationships between color and dynamical history can be established. This will also enable taxonomic classification of asteroids, provide further links between diverse populations such as irregular satellites and TNOs or planetary Trojans, and enable estimates of asteroid diameter with rms uncertainty of 30%. With the addition of light-curve information, rotation periods and phase curves can be measured for large fractions of each population, leading to new insight on physical characteristics. Photometric variability information, together with sparse lightcurve inversion, will allow spin state and shape estimation for up to two orders of magnitude more objects than presently known. This will leverage physical studies of asteroids by constraining the size-strength relationship, which has important implications for the internal structure (solid, fractured, rubble pile) and in turn the collisional evolution of the asteroid belt. Similar information can be gained for other solar system bodies. [1] Parker, A., Ivezic

Design of Spacecraft Missions to Test Kinetic Impact for Asteroid Deflection

NASA Technical Reports Server (NTRS)

Hernandez, Sonia; Barbee, Brent W.

2011-01-01

There are currently over 8,000 known near-Earth asteroids (NEAs), and more are being discovered on a continual basis. More than 1,200 of these are classified as Potentially Hazardous Asteroids (PHAs) because their Minimum Orbit Intersection Distance (MOID) with Earth's orbit is <= 0.05 AU and their estimated diameters are >= 150 m. To date, 178 Earth impact structures have been discovered, indicating that our planet has previously been struck with devastating force by NEAs and will be struck again. Such collisions are aperiodic events and can occur at any time. A variety of techniques have been proposed to defend our planet from NEA impacts by deflecting the incoming asteroid. However, none of these techniques have been tested. Unless rigorous testing is conducted to produce reliable asteroid deflection systems, we will be forced to deploy completely untested -- and therefore unreliable -- deflection missions when a sizable asteroid on a collision course with Earth is discovered. Such missions will have a high probability of failure. We propose to address this problem with a campaign of deflection technology test missions deployed to harmless NEAs. The objective of these missions is to safely evaluate and refine the mission concepts and asteroid deflection system designs. Our current research focuses on the kinetic impactor, one of the simplest proposed asteroid deflection techniques in which a spacecraft is sent to collide with an asteroid at high relative velocity. By deploying test missions in the near future, we can characterize the performance of this deflection technique and resolve any problems inherent to its execution before needing to rely upon it during a true emergency. In this paper we present the methodology and results of our survey, including lists of NEAs for which safe and effective kinetic impactor test missions may be conducted within the next decade. Full mission designs are also presented for the NEAs which offer the best mission opportunities.

OSIRIS-REx, Returning the Asteroid Sample

NASA Technical Reports Server (NTRS)

Ajluni, Thomas, M.; Everett, David F.; Linn, Timothy; Mink, Ronald; Willcockson, William; Wood, Joshua

2015-01-01

This paper addresses the technical aspects of the sample return system for the upcoming Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) asteroid sample return mission. The overall mission design and current implementation are presented as an overview to establish a context for the technical description of the reentry and landing segment of the mission.The prime objective of the OSIRIS-REx mission is to sample a primitive, carbonaceous asteroid and to return that sample to Earth in pristine condition for detailed laboratory analysis. Targeting the near-Earth asteroid Bennu, the mission launches in September 2016 with an Earth reentry date of September 24, 2023.OSIRIS-REx will thoroughly characterize asteroid Bennu providing knowledge of the nature of near-Earth asteroids that is fundamental to understanding planet formation and the origin of life. The return to Earth of pristine samples with known geologic context will enable precise analyses that cannot be duplicated by spacecraft-based instruments, revolutionizing our understanding of the early Solar System. Bennu is both the most accessible carbonaceous asteroid and one of the most potentially Earth-hazardous asteroids known. Study of Bennu addresses multiple NASA objectives to understand the origin of the Solar System and the origin of life and will provide a greater understanding of both the hazards and resources in near-Earth space, serving as a precursor to future human missions to asteroids.This paper focuses on the technical aspects of the Sample Return Capsule (SRC) design and concept of operations, including trajectory design and reentry retrieval. Highlights of the mission are included below.The OSIRIS-REx spacecraft provides the essential functions for an asteroid characterization and sample return mission: attitude control propulsion power thermal control telecommunications command and data handling structural support to ensure successful rendezvous with Bennu characterization of Bennus properties delivery of the sampler to the surface, and return of the spacecraft to the vicinity of the Earth sample collection, performed by the Touch-and-Go Sample Acquisition Mechanism (TAGSAM), to acquire a regolith sample from the surface Earth re-entry and SRC recovery. Following sample collection, OSIRIS-REx drifts away from Bennu until the Asteroid Departure Maneuver is commanded on March 4, 2021, sending OSIRIS-REx on a ballistic return cruise to Earth. No additional large deterministic maneuvers are required to return the SRC to Earth. During the cruise, tracking and trajectory correction maneuvers (TCMs) are performed as necessary to precisely target the entry corridor. As OSIRIS-REx approaches Earth, the reentry plans are reviewed starting about a year before arrival, and preparations begin. The spacecraft is targeted away from the Earth until 7 days before entry. The final two trajectory correction maneuvers bring the spacecraft on target toward the Utah Test and Training Range (UTTR), with sufficient time for contingency resolution. The SRC releases 4 hours prior to atmospheric entry interface and, using the Stardust capsule heritage design, employs a traditional drogue and main parachute descent system for a soft touchdown.

Isolated orbital mass as the primary presentation of a triple-hit lymphoma transformed from a systemic follicular lymphoma.

PubMed

Zhou, Xiao Yi; Lu, Xinyan; Raparia, Kirtee; Chen, Yi-Hua

2018-06-01

Triple-hit lymphoma is a highly aggressive B-cell lymphoma. We report a case of triple-hit lymphoma transformed from systemic follicular lymphoma (FL) after 9-year remission and presented primarily as an isolated orbital mass without systemic symptoms or lymphadenopathy. A 58-year-old female presented with intermittent vertical binocular diplopia, left upper eyelid swelling and pain and was found to have a 2.9 cm orbital mass. Histological section revealed a CD10-positive large B-cell lymphoma, consistent with transformation of FL. Fluorescent in situ hybridization (FISH) analysis demonstrated rearrangements involving C-MYC, BCL-2 and BCL-6 genes, indicating a high grade, triple-hit lymphoma. Triple-hit lymphoma transformed from a low-grade lymphoma may initially present as an isolated orbital mass without systemic evidence of transformation. Early recognition of double or triple-hit lymphomas is important since these patients require aggressive chemotherapy.

Spin Rate Distribution of Small Asteroids Shaped by YORP Effect

NASA Astrophysics Data System (ADS)

Pravec, Petr

2008-09-01

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

Scattering V-type asteroids during the giant planet instability: a step for Jupiter, a leap for basalt

NASA Astrophysics Data System (ADS)

Brasil, P. I. O.; Roig, F.; Nesvorný, D.; Carruba, V.

2017-06-01

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.

Discovery and dynamical characterization of the Amor-class asteroid 2012 XH16

NASA Astrophysics Data System (ADS)

Wlodarczyk, I.; Cernis, K.; Boyle, R. P.; Laugalys, V.

2014-03-01

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.

Automated Design of Propellant-Optimal, End-to-End, Low-Thrust Trajectories for Trojan Asteroid Tours

NASA Technical Reports Server (NTRS)

Stuart, Jeffrey; Howell, Kathleen; Wilson, Roby

2013-01-01

The Sun-Jupiter Trojan asteroids are celestial bodies of great scientific interest as well as potential resources offering water and other mineral resources for longterm human exploration of the solar system. Previous investigations under this project have addressed the automated design of tours within the asteroid swarm. This investigation expands the current automation scheme by incorporating options for a complete trajectory design approach to the Trojan asteroids. Computational aspects of the design procedure are automated such that end-to-end trajectories are generated with a minimum of human interaction after key elements and constraints associated with a proposed mission concept are specified.

Hubble Witnesses an Asteroid Mysteriously Disintegrating

NASA Image and Video Library

2014-03-06

Though fragile comet nuclei have been seen falling apart as they near the Sun, nothing like the slow breakup of an asteroid has ever before been observed in the asteroid belt. A series of Hubble Space Telescope images shows that the fragments are drifting away from each other at a leisurely one mile per hour. This makes it unlikely that the asteroid is disintegrating because of a collision with another asteroid. A plausible explanation is that the asteroid is crumbling due to a subtle effect of sunlight. This causes the rotation rate to slowly increase until centrifugal force pulls the asteroid apart. The asteroid's remnant debris, weighing in at 200,000 tons, will in the future provide a rich source of meteoroids. Hubble Observation of P/2013 R3 - November 15, 2013 Credit: NASA, ESA, and D. Jewitt (University of California, Los Angeles) Read more: 1.usa.gov/1ig2E0x NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

AIDA: Asteroid Impact & Deflection Assessment

NASA Astrophysics Data System (ADS)

Cheng, Andrew; Michel, Patrick; Ulamec, Stephan; Reed, Cheryl; Galvez, Andres; Carnelli, Ian

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.

The OSIRIS-REx Visible and InfraRed Spectrometer (OVIRS): Spectral Maps of the Asteroid Bennu

NASA Astrophysics Data System (ADS)

Reuter, D. C.; Simon, A. A.; Hair, J.; Lunsford, A.; Manthripragada, S.; Bly, V.; Bos, B.; Brambora, C.; Caldwell, E.; Casto, G.; Dolch, Z.; Finneran, P.; Jennings, D.; Jhabvala, M.; Matson, E.; McLelland, M.; Roher, W.; Sullivan, T.; Weigle, E.; Wen, Y.; Wilson, D.; Lauretta, D. S.

2018-03-01

The OSIRIS-REx Visible and Infrared Spectrometer (OVIRS) is a point spectrometer covering the spectral range of 0.4 to 4.3 microns (25,000-2300 cm-1). Its primary purpose is to map the surface composition of the asteroid Bennu, the target asteroid of the OSIRIS-REx asteroid sample return mission. The information it returns will help guide the selection of the sample site. It will also provide global context for the sample and high spatial resolution spectra that can be related to spatially unresolved terrestrial observations of asteroids. It is a compact, low-mass (17.8 kg), power efficient (8.8 W average), and robust instrument with the sensitivity needed to detect a 5% spectral absorption feature on a very dark surface (3% reflectance) in the inner solar system (0.89-1.35 AU). It, in combination with the other instruments on the OSIRIS-REx Mission, will provide an unprecedented view of an asteroid's surface.

Hydrated Minerals on Asteroids: The Astronomical Record

NASA Technical Reports Server (NTRS)

Rivkin, A. S.; Howell, E. S.; Vilas, F.; Lebofsky, L. A.

2003-01-01

Knowledge of the hydrated mineral inventory on the asteroids is important for deducing the origin of Earth's water, interpreting the meteorite record, and unraveling the processes occurring during the earliest times in solar system history. Reflectance spectroscopy shows absorption features in both the 0.6-0.8 and 2.5-3.5-micron regions, which are diagnostic of or associated with hydrated minerals. Observations in those regions show that hydrated minerals are common in the mid-asteroid belt, and can be found in unexpected spectral groupings as well. Asteroid groups formerly associated with mineralogies assumed to have high-temperature formation, such as M- and E-class steroids, have been observed to have hydration features in their reflectance spectra. Some asteroids have apparently been heated to several hundred degrees Celsius, enough to destroy some fraction of their phyllosilicates. Others have rotational variation suggesting that heating was uneven. We summarize this work, and present the astronomical evidence for water- and Hydroxl-bearing minerals on asteroids.

Asteroid Impact Mission (aim) & Deflection Assessment: AN Opportunity to Understand Impact Dynamics and Modelling

NASA Astrophysics Data System (ADS)

Galvez, A.; Carnelli, I.; Fontaine, M.; Corral Van Damme, C.

2012-09-01

ESA's Future Preparation and Strategic Studies Office has carried out the Asteroid Impact Mission (AIM) study with the objective of defining an affordable and fully independent mission element that ESA could contribute to an Asteroid Impact Deflection Assessment campaign (AIDA), a joint effort of ESA, JHU/APL, NASA, OCA and DLR. The mission design foresees two independent spacecraft, one impactor (DART) and one rendezvous probe (AIM). The target of this mission is the binary asteroid system (65803) Didymos (1996 GT): one spacecraft, DART, would impact the secondary of the Didymos binary system while AIM would observe and measure any the change in the relative orbit. For this joint project, the timing of the experiment is set (maximum proximity of the target to Earth allowing for ground-based characterisation of the experiment) but the spacecraft are still able to pursue their missions fully independently. This paper describes in particular the AIM rendezvous mission concept.

Discovery of a Satellite around a Near-Earth Asteroid

NASA Astrophysics Data System (ADS)

1997-07-01

In the course of the major observational programme of asteroids by the Institute of Planetary Exploration of the German Aerospace Research Establishment (DLR) [1] in Berlin, two of the staff astronomers, Stefano Mottola and Gerhard Hahn , have discovered a small satellite (moon) orbiting the asteroid (3671) Dionysus. The new measurements were obtained with the DLR CCD Camera attached at the 60-cm Bochum telescope at the ESO La Silla Observatory in Chile. This is only the second known case of an asteroid with a moon. Moons and planets Until recently, natural satellites were only known around the major planets . The Moon orbits the Earth, there are two tiny moons around Mars, each of the giant planets Jupiter, Saturn, Uranus and Neptune has many more, and even the smallest and outermost, Pluto, is accompanied by one [2]. However, the new discovery now strengthens the belief of many astronomers that some, perhaps even a substantial number of the many thousands of minor planets (asteroids) in the solar system may also possess their own moons. The first discovery of a satellite orbiting an asteroid was made by the NASA Galileo spacecraft, whose imagery, obtained during a fly-by of asteroid (253) Ida in August 1993, unveiled a small moon that has since been given the name Dactyl. (3671) Dionysus: an Earth-crossing asteroid In the framework of the DLR asteroid monitoring programme, image sequences are acquired to measure an asteroid's brightness variations caused by the changing amount of sunlight reflected from the asteroid's illuminated surface as it spins, due to its irregular shape. The brightness variations may be used to derive the asteroid's rotational properties, such as speed of rotation and spin axis orientation. Asteroid Dionysus [3] was put on the observing list because it belongs to a special class of asteroids, the members of which occasionally come very close to the Earth and have a small, but non-negligible chance of colliding with our planet. Most of these objects move in highly elliptical orbits that lie partly inside, partly outside that of the Earth. They are accordingly referred to as `Earth-crossing asteroids' or Apollo-type asteroids , after the proto-type of this group, (1862) Apollo, that was discovered in 1932 by Karl Reinmuth in Heidelberg [4]. The orbital characteristics of Dionysus lead to moderately close approaches to the Earth every 13 years, with the one in 1997 being the first since its discovery that is favourable for extensive observations. On July 6, 1997, it passed within 17 million km of our planet. At that time it was visible from the southern hemisphere with a moderately-sized telescope as a relatively fast-moving object. The strange lightcurve of asteroid (3671) Dionysus Caption to ESO PR Photo 20/97 [GIF, 10k] The first observations of the brightness of this asteroid in late May 1997 showed a `normal' two-maxima-two-minima lightcurve (change of brightness with time), typical of rotating non-spherical bodies. The period of rotation was 2.7 hours, i.e., this asteroid spins almost nine times as fast as the Earth. However lightcurves observed on two subsequent nights were strikingly different from the previous ones. In both cases a deeper and shifted dip was seen, indicative of an attenuation - an additional dimming of the sunlight reflected by the asteroid, cf. ESO Press Photo 20/97 . The observers hypothesised that these lightcurve features were due to an eclipse by an unknown object moving in an orbit around (3671) Dionysus , thereby covering part of the illuminated surface of the asteroid at regular time intervals [5]. Fortunately, this hypothesis can be checked, because the phenomenon should then repeat itself periodically. Accordingly, the DLR scientists made a prediction for the next occurences of dips in the lightcurve, based on the time difference between the two observed events. Confirmation of the satellite Contacts were made with observers located at other observatories, in order to secure lightcurve coverage over a longer period of time than was possible from La Silla alone. As a result, a series of lightcurve measurements were performed from June 3 to 9 in close cooperation with Petr Pravec and Lenka Sarounova working at the Ondrejov Observatory, near Prague in the Czech Republic. Luckily, the weather conditions were favourable at both sites and the dips in the lightcurve were indeed observed at the predicted times. Based on the four well observed events, it was then possible to determine a period of 1.155 days for their occurence. Thus, the hypothesis of a satellite orbiting around Dionysus was confirmed. As a result, the International Astronomical Union's Minor Planet Center located in Cambridge (MA, USA) promptly gave a provisional designation to the new satellite - S/1997 (3671) 1 . How big is Dionysus? Meanwhile, in Hawaii, the world's largest infrared telescope was being trained on Dionysus to obtain information about its size and composition. Alan Harris , also a scientist from the DLR in Berlin, and John Davies from the Joint Astronomy Centre in Hilo, Hawaii, observed the thermal infrared radiation emitted by Dionysus with the 3.8-m United Kingdom Infrared Telescope (UKIRT) situated on Mauna Kea. Similar observations over a broader spectral range were also made by the European Space Agency's orbiting Infrared Space Observatory. The thermal or "heat" radiation emitted by an asteroid depends on its size and the amount of sunlight it absorbs (darker bodies being warmer). In the case of Dionysus the measured radiation was much weaker than expected, indicating that the asteroid has an intrinsically bright (reflective) surface and is only about 1 km in diameter. This is much smaller than (253) Ida, the only other asteroid known to have a moon, which is about 60 km across. Further observations Eventually it should be possible to determine the orbital radius of the satellite, its size and the inclination of its orbital plane. In order to obtain the data necessary for these determinations, observations will be continued during the present period of good visibility that lasts until September-October 1997. For this reason the discoverers have initiated an international observation campaign devoted to the study of this intriguing object and now involving astronomers from many countries. How common are such satellites? Satellites in orbit around small bodies in the solar system - asteroids and cometary nuclei - have been predicted on theoretical grounds for a long time, even though there is no consensus among planetary scientists about the actual numbers of such systems. Hints about the existence of asteroid satellites also come from the presence of double impact craters on the Moon and other planetary surfaces. This suggests that the projectiles forming these craters were `double' asteroids. Moreover, measurements obtained when an asteroid passes in front of a relatively bright star (a so-called `occultation') have on a few occasions shown features which could be interpreted as due to the presence of a satellite. However, because of the difficult nature of such measurements, it has never been possible to draw unambiguous conclusions. The existence of double asteroids was invoked earlier by Petr Pravec and Gerhard Hahn to explain the unusual features observed in the lightcurves of two other Earth-approaching asteroids 1991 VH and 1994 AW1 . In the case of Dionysus , however, it is possible to predict eclipse events and to confirm them by subsequent measurements. There is therefore mounting evidence that asteroid binary systems might be comparatively common. Observational programmes like the present one by the DLR and Ondrejov groups will help to verify this possibility. Where to find additional information Detailed and up-to-date information about (3671) Dionysus can be found in the Web at the following URL: http://earn.dlr.de/dionysus. Notes: [1] This institute and its parent organisation are known in Germany as Institut fuer Planetenerkundung and Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR) . [2] See ESO Press Release 09/94 of 18 May 1994. [3] Asteroids are small solid planetary bodies revolving around the Sun in orbits that are mostly located in the so-called Main Asteroid Belt, confined between the orbits of Mars and Jupiter. Most of them are thought to be fragments derived from catastrophic, past collisions between larger asteroids. By mid-1997, the orbits of about 8000 asteroids in the solar system were sufficiently well known to allow them to be officially numbered by the rules of the International Astronomical Union. (3671) Dionysus was discovered in 1984 at the Palomar Observatory (California, USA) and is named after the Greek god of wine. [4] The gravitational influence of the giant planet Jupiter can modify the orbits of asteroids located in particular regions of the Main Belt (the effect is refered to as `orbital perturbations'). As a result, the orbit of an asteroid may `cross' that of a major planet, and eventually it may become a NEO , i.e. a near-Earth object. The orbits of NEO's are highly unstable over times comparable to the age of the solar system. This instability can result in a collision with one of the terrestrial (inner) planets, or with the Sun, or in the ejection of the asteroid out of the solar system. The present orbit of (3671) Dionysus is such that this object is not likely to collide with the Earth in the foreseeable future. [5] The method of analyzing the lightcurve of Dionysus consists of `removing' (subtracting) the normal short-period brightness variations due to rotation of the asteroid and plotting the residuals against time, cf. Press Photo 20/97. The residual lightcurve shows a clear resemblance with typical lightcurves of eclipsing binary stellar systems (in which two stars move around each other, producing mutual eclipses) and leads to a model of two bodies revolving around a common gravitational centre, in an orbital plane containing both the Earth and the Sun. How to obtain ESO Press Information ESO Press Information is made available on the World-Wide Web (URL: http://www.eso.org../). ESO Press Photos may be reproduced, if credit is given to the European Southern Observatory.

GPU-accelerated computational tool for studying the effectiveness of asteroid disruption techniques

NASA Astrophysics Data System (ADS)

Zimmerman, Ben J.; Wie, Bong

2016-10-01

This paper presents the development of a new Graphics Processing Unit (GPU) accelerated computational tool for asteroid disruption techniques. Numerical simulations are completed using the high-order spectral difference (SD) method. Due to the compact nature of the SD method, it is well suited for implementation with the GPU architecture, hence solutions are generated at orders of magnitude faster than the Central Processing Unit (CPU) counterpart. A multiphase model integrated with the SD method is introduced, and several asteroid disruption simulations are conducted, including kinetic-energy impactors, multi-kinetic energy impactor systems, and nuclear options. Results illustrate the benefits of using multi-kinetic energy impactor systems when compared to a single impactor system. In addition, the effectiveness of nuclear options is observed.

Meteoroid Impact Ejecta Detection by Nanosatellites for Asteroid Surface Characterization

NASA Astrophysics Data System (ADS)

Lee, N.; Close, S.; Goel, A.

2015-12-01

Asteroids are constantly bombarded by much smaller meteoroids at extremely high speeds, which results in erosion of the material on the asteroid surface. Some of this material is vaporized and ionized, forming a plasma that is ejected into the environment around the asteroid where it can be detected by a constellation of closely orbiting nanosatellites. We present a concept to leverage this natural phenomenon and to analyze this excavated material using low-power plasma sensors on nanosatellites in order to determine the composition of the asteroid surface. This concept would enable a constellation of nanosatellites to provide useful data complementing existing techniques such as spectroscopy, which require larger and more power-hungry sensors. Possible mission architectures include precursor exploratory missions using nanosatellites to survey and identify asteroid candidates worthy of further study by a large spacecraft, or simultaneous exploration by a nanosatellite constellation with a larger parent spacecraft to decrease the time required to cover the entire asteroid surface. The use of meteoroid impact plasma to analyze the surface composition of asteroids will not only produce measurements that have not been previously obtained, including the molecular composition of the surface, but will also yield a better measurement of the meteoroid flux in the vicinity of the asteroid. Current meteoroid models are poorly constrained beyond the orbit of Mars, due to scarcity of data. If this technology is used to survey asteroids in the main belt, it will offer a dramatic increase in the availability of meteoroid flux measurements in deep space, identifying previously unknown meteoroid streams and providing additional data to support models of solar system dust dynamics.

Binary asteroid population. 3. Secondary rotations and elongations

NASA Astrophysics Data System (ADS)

Pravec, P.; Scheirich, P.; Kušnirák, P.; Hornoch, K.; Galád, A.; Naidu, S. P.; Pray, D. P.; Világi, J.; Gajdoš, Š.; Kornoš, L.; Krugly, Yu. N.; Cooney, W. R.; Gross, J.; Terrell, D.; Gaftonyuk, N.; Pollock, J.; Husárik, M.; Chiorny, V.; Stephens, R. D.; Durkee, R.; Reddy, V.; Dyvig, R.; Vraštil, J.; Žižka, J.; Mottola, S.; Hellmich, S.; Oey, J.; Benishek, V.; Kryszczyńska, A.; Higgins, D.; Ries, J.; Marchis, F.; Baek, M.; Macomber, B.; Inasaridze, R.; Kvaratskhelia, O.; Ayvazian, V.; Rumyantsev, V.; Masi, G.; Colas, F.; Lecacheux, J.; Montaigut, R.; Leroy, A.; Brown, P.; Krzeminski, Z.; Molotov, I.; Reichart, D.; Haislip, J.; LaCluyze, A.

2016-03-01

We collected data on rotations and elongations of 46 secondaries of binary and triple systems among near-Earth, Mars-crossing and small main belt asteroids. 24 were found or are strongly suspected to be synchronous (in 1:1 spin-orbit resonance), and the other 22, generally on more distant and/or eccentric orbits, were found or are suggested to have asynchronous rotations. For 18 of the synchronous secondaries, we constrained their librational angles, finding that their long axes pointed to within 20° of the primary on most epochs. The observed anti-correlation of secondary synchroneity with orbital eccentricity and the limited librational angles agree with the theories by Ćuk and Nesvorný (Ćuk, M., Nesvorný, D. [2010]. Icarus 207, 732-743) and Naidu and Margot (Naidu, S.P., Margot, J.-L. [2015]. Astron. J. 149, 80). A reason for the asynchronous secondaries being on wider orbits than synchronous ones may be longer tidal circularization time scales at larger semi-major axes. The asynchronous secondaries show relatively fast spins; their rotation periods are typically < 10 h. An intriguing observation is a paucity of chaotic secondary rotations; with an exception of (35107) 1991 VH, the secondary rotations are single-periodic with no signs of chaotic rotation and their periods are constant on timescales from weeks to years. The secondary equatorial elongations show an upper limit of a2 /b2 ∼ 1.5 . The lack of synchronous secondaries with greater elongations appears consistent, considering uncertainties of the axis ratio estimates, with the theory by Ćuk and Nesvorný that predicts large regions of chaotic rotation in the phase space for a2 /b2 ≳√{ 2 } . Alternatively, secondaries may not form or stay very elongated in gravitational (tidal) field of the primary. It could be due to the secondary fission mechanism suggested by Jacobson and Scheeres (Jacobson, S.A., Scheeres, D.J. [2011]. Icarus 214, 161-178), as its efficiency is correlated with the secondary elongation. Sharma (Sharma, I. [2014]. Icarus 229, 278-294) found that rubble-pile satellites with a2 /b2 ≲ 1.5 are more stable to finite structural perturbations than more elongated ones. It appears that more elongated secondaries, if they originally formed in spin fission of parent asteroid, are less likely to survive intact and they more frequently fail or fission.

Lifetime of binary asteroids versus gravitational encounters and collisions

NASA Technical Reports Server (NTRS)

Chauvineau, Bertrand; Farinella, Paolo; Mignard, F.

1992-01-01

We investigate the effect on the dynamics of a binary asteroid in the case of a near encounter with a third body. The dynamics of the binary is modeled as a two-body problem perturbed by an approaching body in the following ways: near encounters and collisions with a component of the system. In each case, the typical value of the two-body energy variation is estimated, and a random walk for the cumulative effect is assumed. Results are applied to some binary asteroid candidates. The main conclusion is that the collisional disruption is the dominant effect, giving lifetimes comparable to or larger than the age of the solar system.

First known terrestrial impact of a binary asteroid from a main belt breakup event.

PubMed

Ormö, Jens; Sturkell, Erik; Alwmark, Carl; Melosh, Jay

2014-10-23

Approximately 470 million years ago one of the largest cosmic catastrophes occurred in our solar system since the accretion of the planets. A 200-km large asteroid was disrupted by a collision in the Main Asteroid Belt, which spawned fragments into Earth crossing orbits. This had tremendous consequences for the meteorite production and cratering rate during several millions of years following the event. The 7.5-km wide Lockne crater, central Sweden, is known to be a member of this family. We here provide evidence that Lockne and its nearby companion, the 0.7-km diameter, contemporaneous, Målingen crater, formed by the impact of a binary, presumably 'rubble pile' asteroid. This newly discovered crater doublet provides a unique reference for impacts by combined, and poorly consolidated projectiles, as well as for the development of binary asteroids.

Samples from Differentiated Asteroids; Regolithic Achondrites

NASA Technical Reports Server (NTRS)

Herrin J. S.; Ross, A. J.; Cartwright, J. A.; Ross, D. K.; Zolensky, Michael E.; Jenniskens, P.

2011-01-01

Differentiated and partially differentiated asteroids preserve a glimpse of planet formation frozen in time from the early solar system and thus are attractive targets for future exploration. Samples of such asteroids arrive to Earth in the form of achondrite meteorites. Many achondrites, particularly those thought to be most representative of asteroidal regolith, contain a diverse assortment of materials both indigenous and exogenous to the original igneous parent body intermixed at microscopic scales. Remote sensing spacecraft and landers would have difficulty deciphering individual components at these spatial scales, potentially leading to confusing results. Sample return would thus be much more informative than a robotic probe. In this and a companion abstract [1] we consider two regolithic achondrite types, howardites and (polymict) ureilites, in order to evaluate what materials might occur in samples returned from surfaces of differentiated asteroids and what sampling strategies might be prudent.

The size distribution of the earth-approaching asteroids

NASA Technical Reports Server (NTRS)

Rabinowitz, D. L.

1993-01-01

The discovery circumstances of the first asteroids ever observed outside the earth's atmosphere but within the neighborhood of the earth-moon system are described. Four natural objects with diameters in the range 5-50 m were detected during a search for earth-approaching asteroids conducted each month at the 0.91-m Spacewatch Telescope at Kitt Peak. An additional 19 earth approachers with sizes in the range 50 m to 5 km were discovered. These obervations determine the cumulative flux of asteroids near earth as a function of absolute magnitude. For asteroids larger than about 100 m, a power-law dependence with exponent of about 0.9 is observed, consistent with their evolution from the main-belt population. At about 10 m, the flux is more than two orders of magnitude greater than this power-law extrapolation.

Near Earth Asteroids- Prospection, Orbit Modification and Mining

NASA Astrophysics Data System (ADS)

Grandl, W.; Bazso, A.

2014-04-01

The number of known Near Earth Asteroids (NEAs) has increased continuously during the last decades. Now we understand the role of asteroid impacts for the evolution of life on Earth. To ensure that mankind will survive in the long run, we have to face the "asteroid threat" seriously. On one hand we will have to develop methods of detection and deflection for Hazardous Asteroids, on the other hand we can use these methods to modify their orbits and exploit their resources. Rare-earth elements, rare metals like platinum group elements, etc. may be extracted more easily from NEAs than from terrestrial soil, without environmental pollution or political and social problems. In a first step NEAs, which are expected to contain resources like nickel-iron, platinum group metals or rare-earth elements, will be prospected by robotic probes. Then a number of asteroids with a minimum bulk density of 2 g/cm^3 and a diameter of 150 to 500 m will be selected for mining. Given the long duration of an individual mission time of 10-20 years, the authors propose a "pipeline" concept. While the observation of NEAs can be done in parallel, the precursor missions of the the next phase can be launched in short intervals, giving time for technical corrections and upgrades. In this way a continuous data flow is established and there are no idle times. For our purpose Potentially Hazardous Asteroids (PHAs) seem to be a favorable choice for the following reasons: They have frequent closeencounters to Earth, their minimum orbit intersection distance is less than 0.05 AU (Astronomic Units) and they have diameters exceeding 150 meters. The necessary velocity change (delta V) for a spaceship is below 12 km/s to reach the PHA. The authors propose to modify the orbits of the chosen PHAs by orbital maneuvers from solar orbits to stable Earth orbits beyond the Moon. To change the orbits of these celestial bodies it is necessary to develop advanced propulsion systems. They must be able to deliver high thrust and specific impulse to move the huge masses of the asteroids. Such a propulsion system could be the Bussard Fusion System, also known as the quiet-electricdischarge (QED) engine. It uses electrostatic fusion devices to generate electrical power. The fuel consists of Deuterium and Helium3 that are fusing to Helium4 plus protons releasing 18.3 MeV of energy per reaction. The charged protons escape from the confinement; their kinetic energy can be converted to electricity or be used directly as a plasma beam for generating thrust. For the reaction a specific energy of 3.5x1014 Joule/kg can be computed, i.e. orders-ofmagnitude higher than for any existing propulsion system. As an example we take the Asteroid with the designation 2008 EV5. It is classified as an Aten group asteroid with a mean diameter of 450 meters and belongs to spectral type S (stony asteroids). Our mass estimate (using a bulk density of 3 g/cm^3) is 1.4x1011 kg. To transfer 2008 EV5 to an Earth-like orbit the energy required is estimated to be in the order of 2.8x1018 Joule. This is the difference in Kepler energy between the NEA's current orbit and the Earth's orbit around the sun. Using the Bussard Fusion System the amount of fuel would be approx. 8000 kg of Helium3. To move an asteroid by remote control the authors propose to design unmanned space tugs which are propelled by Bussard Fusion Engines. A pair of space tugs is docked to each asteroid using drilling anchors. The fusion engines of the tugs then apply the thrust forces for the maneuvers. The first tug, which carries the main fuel quantity, applies the primary force for the orbital maneuvers. The second one adjust the flight track by short engine thrusts.

NASA's Hubble Sees Asteroid Spout Six Comet-like Tails

NASA Image and Video Library

2013-11-13

This NASA Hubble Space Telescope set of images reveals a never-before-seen set of six comet-like tails radiating from a body in the asteroid belt, designated P/2013 P5. The asteroid was discovered as an unusually fuzzy-looking object with the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) survey telescope in Hawaii. The multiple tails were discovered in Hubble images taken on Sept. 10, 2013. When Hubble returned to the asteroid on Sept. 23, the asteroid's appearance had totally changed. It looked as if the entire structure had swung around. One interpretation is that the asteroid's rotation rate has been increased to the point where dust is falling off the surface and escaping into space where the pressure of sunlight sweeps out fingerlike tails. According to this theory, the asteroid's spin has been accelerated by the gentle push of sunlight. The object, estimated to be no more than 1,400 feet across, has ejected dust for at least five months, based on analysis of the tail structure. These visible-light, false-color images were taken with Hubble's Wide Field Camera 3. Object Name: P/2013 P5 Image Type: Astronomical/Annotated Credit: NASA, ESA, and D. Jewitt (UCLA) NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

NASA's Hubble Sees Asteroid Spout Six Comet-like Tails

NASA Image and Video Library

2013-11-13

P/2013 P5 on September 23, 2013. --- This NASA Hubble Space Telescope set of images reveals a never-before-seen set of six comet-like tails radiating from a body in the asteroid belt, designated P/2013 P5. The asteroid was discovered as an unusually fuzzy-looking object with the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) survey telescope in Hawaii. The multiple tails were discovered in Hubble images taken on Sept. 10, 2013. When Hubble returned to the asteroid on Sept. 23, the asteroid's appearance had totally changed. It looked as if the entire structure had swung around. One interpretation is that the asteroid's rotation rate has been increased to the point where dust is falling off the surface and escaping into space where the pressure of sunlight sweeps out fingerlike tails. According to this theory, the asteroid's spin has been accelerated by the gentle push of sunlight. The object, estimated to be no more than 1,400 feet across, has ejected dust for at least five months, based on analysis of the tail structure. These visible-light, false-color images were taken with Hubble's Wide Field Camera 3. Object Name: P/2013 P5 Image Type: Astronomical/Annotated Credit: NASA, ESA, and D. Jewitt (UCLA) NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

NASA's Hubble Sees Asteroid Spout Six Comet-like Tails

NASA Image and Video Library

2013-11-13

P/2013 P5 on September 10, 2013. --- This NASA Hubble Space Telescope set of images reveals a never-before-seen set of six comet-like tails radiating from a body in the asteroid belt, designated P/2013 P5. The asteroid was discovered as an unusually fuzzy-looking object with the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) survey telescope in Hawaii. The multiple tails were discovered in Hubble images taken on Sept. 10, 2013. When Hubble returned to the asteroid on Sept. 23, the asteroid's appearance had totally changed. It looked as if the entire structure had swung around. One interpretation is that the asteroid's rotation rate has been increased to the point where dust is falling off the surface and escaping into space where the pressure of sunlight sweeps out fingerlike tails. According to this theory, the asteroid's spin has been accelerated by the gentle push of sunlight. The object, estimated to be no more than 1,400 feet across, has ejected dust for at least five months, based on analysis of the tail structure. These visible-light, false-color images were taken with Hubble's Wide Field Camera 3. Object Name: P/2013 P5 Image Type: Astronomical/Annotated Credit: NASA, ESA, and D. Jewitt (UCLA) NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

On the stability and collisions in triple stellar systems

NASA Astrophysics Data System (ADS)

He, Matthias Y.; Petrovich, Cristobal

2018-02-01

A significant fraction of main-sequence (MS) stars are part of a triple system. We study the long-term stability and dynamical outcomes of triple stellar systems using a large number of long-term direct N-body integrations with relativistic precession. We find that the previously proposed stability criteria by Eggleton & Kiseleva and Mardling & Aarseth predict the stability against ejections reasonably well for a wide range of parameters. Assuming that the triple stellar systems follow orbital and mass distributions from FGK binary stars in the field, we find that ˜ 1 per cent and ˜ 0.5 per cent of the triple systems lead to a direct head-on collision (impact velocity ˜ escape velocity) between MS stars and between a MS star and a stellar-mass compact object, respectively. We conclude that triple interactions are the dominant channel for direct collisions involving a MS star in the field with a rate of one event every ˜100 years in the Milky Way. We estimate that the fraction of triple systems that form short-period binaries is up to ˜ 23 per cent with only up to ˜ 13 per cent being the result of three-body interactions with tidal dissipation, which is consistent with previous work using a secular code.

Design and validation of a GNC system for missions to asteroids: the AIM scenario

NASA Astrophysics Data System (ADS)

Pellacani, A.; Kicman, P.; Suatoni, M.; Casasco, M.; Gil, J.; Carnelli, I.

2017-12-01

Deep space missions, and in particular missions to asteroids, impose a certain level of autonomy that depends on the mission objectives. If the mission requires the spacecraft to perform close approaches to the target body (the extreme case being a landing scenario), the autonomy level must be increased to guarantee the fast and reactive response which is required in both nominal and contingency operations. The GNC system must be designed in accordance with the required level of autonomy. The GNC system designed and tested in the frame of ESA's Asteroid Impact Mission (AIM) system studies (Phase A/B1 and Consolidation Phase) is an example of an autonomous GNC system that meets the challenging objectives of AIM. The paper reports the design of such GNC system and its validation through a DDVV plan that includes Model-in-the-Loop and Hardware-in-the-Loop testing. Main focus is the translational navigation, which is able to provide online the relative state estimation with respect to the target body using exclusively cameras as relative navigation sensors. The relative navigation outputs are meant to be used for nominal spacecraft trajectory corrections as well as to estimate the collision risk with the asteroid and, if needed, to command the execution of a collision avoidance manoeuvre to guarantee spacecraft safety

Direct imaging discovery of a Jovian exoplanet within a triple-star system.

PubMed

Wagner, Kevin; Apai, Dániel; Kasper, Markus; Kratter, Kaitlin; McClure, Melissa; Robberto, Massimo; Beuzit, Jean-Luc

2016-08-12

Direct imaging allows for the detection and characterization of exoplanets via their thermal emission. We report the discovery via imaging of a young Jovian planet in a triple-star system and characterize its atmospheric properties through near-infrared spectroscopy. The semimajor axis of the planet is closer relative to that of its hierarchical triple-star system than for any known exoplanet within a stellar binary or triple, making HD 131399 dynamically unlike any other known system. The location of HD 131399Ab on a wide orbit in a triple system demonstrates that massive planets may be found on long and possibly unstable orbits in multistar systems. HD 131399Ab is one of the lowest mass (4 ± 1 Jupiter masses) and coldest (850 ± 50 kelvin) exoplanets to have been directly imaged. Copyright © 2016, American Association for the Advancement of Science.

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

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

We have combined the NEOWISE and Sloan Digital Sky Survey data to study the albedos of 24,353 asteroids with candidate taxonomic classifications derived using Sloan photometry. We find a wide range of moderate to high albedos for candidate S-type asteroids that are analogous to the S complex defined by previous spectrophotometrically based taxonomic systems. The candidate C-type asteroids, while generally very dark, have a tail of higher albedos that overlaps the S types. The albedo distribution for asteroids with a photometrically derived Q classification is extremely similar to those of the S types. Asteroids with similar colors to (4) Vestamore » have higher albedos than the S types, and most have orbital elements similar to known Vesta family members. Finally, we show that the relative reflectance at 3.4 and 4.6 {mu}m is higher for D-type asteroids and suggest that their red visible and near-infrared spectral slope extends out to these wavelengths. Understanding the relationship between size, albedo, and taxonomic classification is complicated by the fact that the objects with classifications were selected from the visible/near-infrared Sloan Moving Object Catalog, which is biased against fainter asteroids, including those with lower albedos.« less

Spatial Mapping of NEO 2008 EV5 Using Small Satellite Formation Flying and Steresoscopic Technology

NASA Astrophysics Data System (ADS)

Gonzalez, Juan; Singh Derewa, Chrishma

2016-10-01

NASA is currently developing the first-ever robotic Asteroid Redirect Robotic Mission (ARRM) to the near-Earth asteroid 2008 EV5 with the objective to capture a multi-ton boulder from the asteroids surface and use its mass to redirect its parent into a CIS lunar orbit where astronauts will study its physical and chemical composition.A critical step towards achieving this mission is to effectively map the target asteroid, identify the candidate boulder for retrieval and characterize its critical parameters. Currently, ARRM utilizes a laser altimeter to characterize the height of the boulders and mapping for final autonomous control of the capture. The proposed Lava-Kusha mission provides the increased of stereoscopic imaging and mapping, not only the Earthward side of the asteroid which has been observed for possible landing sites, but mapping the whole asteroid. LKM will enhance the fidelity of the data collected by the laser altimeter and gather improved topographic data for future Orion missions to 2008 EV5 once in cis lunar space.LKM consists of two low cost small satellites (6U) as a part of the ARRM. They will launch with ARRM as an integrated part of the system. Once at the target, this formation of pathfinder satellites will image the mission critical boulder to ensure the system design can support its removal. LKM will conduct a series of flybys prior to ARRM's rendezvous. LKMs stereoscopic cameras will provide detailed surveys of the boulder's terrain and environment to ensure ARRM can operate safely, reach the location and interface with the boulder. The LKM attitude control and cold gas propulsion system will enable formation maintenance maneuvers for global mapping of asteroid 2008 EV5 at an altitude of 100 km to a high-spatial resolution imaging altitude of 5 km.LKM will demonstrate formation flying in deep space and the reliability of stereoscopic cameras to precisely identify a specific target and provide physical characterization of an asteroid. An assessment of the off-the-shelf technology used at JPL will be provided also with technology readiness descriptions, mission architecture, cost analysis and future work required to make the proposed LKM mission a partner to ARRM.

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

The Gaia Investigation of the Solar System

NASA Astrophysics Data System (ADS)

Delbo, Marco; Tanga, Paolo; Mignard, Francois; Cellino, Alberto; Hestroffer, Daniel

2015-08-01

The space mission Gaia of the European Space Agency (ESA) has begun its scientific whole-sky survey of all astrophysical sources with V<=20 in July 2014. The high precision astrometry is the main science driver for the mission, but Gaia will also obtain visible photometry and low-resolution spectroscopy of the observed sources, including solar system small bodies. Preliminary results show a good quality of the data, in general, in line with the expected pre-flight specifications. These data will consist a mine of information for a remote-sensing exploration of the small worlds of our Solar System. Indeed, ~250,000 asteroids will be observed by Gaia throughout its 5-years-long mission. After an update about the status of the mission and the on-going data analysis, including some preliminary results, we are going to present the plans for the data releases, the first foreseen at the end of 2016, and the general data treatment.We will show how Gaia spectroscopy will allow up to map the composition of about 100,000 asteroids throughout the Main Belt, with high signal to noise ratio. Given its advantage position outside the Earth's atmosphere, the blue part of the spectrum (roughly below 0.5 micron) will be observed for an unprecedented number of asteroids.Additionally, precise photometry and astrometry will also be important to reveal the physical nature of these small bodies. In particular, it is estimated that three-dimensional shapes, rotation, period and pole orientation will be derived for 10,000 asteroids. The masses of about 150 of the largest asteroids, will be determined from measurements of the orbital gravitational perturbations that these bodies will exert on small asteroids during mutual close approaches.Moreover, the combination of Gaia data (delivering masses and shapes) with infrared radiometric observations, e.g. from the NASA WISE mission (informing us about the size of the bodies), will allow precise asteroid bulk densities to be determined. The bulk density and the internal structure are among the most important characteristics of asteroids, that are currently some of the least constrained.

Compositional studies of primitive asteroids

NASA Technical Reports Server (NTRS)

Vilas, Faith

1991-01-01

The aqueous alteration history in the solar system are studied through acquiring additional CCD reflectance spectra in the blue-UV through near-IR spectral region and analyzing these spectra for information about iron oxides in phyllosilicates identified in the CM and CI carbonaceous chondrites. Emphasis is on the main-belt and Cybele primitive asteroids, as these asteroids show spectral diversity and are also spectral analogues for known meteorite samples. The porphyrin bands found in organics near 0.4 micron is also sought.

Three dimensional modelling for the target asteroid of HAYABUSA

NASA Astrophysics Data System (ADS)

Demura, H.; Kobayashi, S.; Asada, N.; Hashimoto, T.; Saito, J.

Hayabusa program is the first sample return mission of Japan. This was launched at May 9 2003, and will arrive at the target asteroid 25143 Itokawa on June 2005. The spacecraft has three optical navigation cameras, which are two wide angle ones and a telescopic one. The telescope with a filter wheel was named AMICA (Asteroid Multiband Imaging CAmera). We are going to model a shape of the target asteroid by this telescope; expected resolution: 1m/pixel at 10 km in distanc, field of view: 5.7 squared degrees, MPP-type CCD with 1024 x 1000 pixels. Because size of the Hayabusa is about 1x1x1 m, our goal is shape modeling with about 1m in precision on the basis of a camera system with scanning by rotation of the asteroid. This image-based modeling requires sequential images via AMICA and a history of distance between the asteroid and Hayabusa provided by a Laser Range Finder. We established a system of hierarchically recursive search with sub-pixel matching of Ground Control Points, which are picked up with Susan Operator. The matched dataset is restored with a restriction of epipolar geometry, and the obtained a group of three dimensional points are converted to a polygon model with Delaunay Triangulation. The current status of our development for the shape modeling is displayed.

Incorporating Uncertainty into Spacecraft Mission and Trajectory Design

NASA Astrophysics Data System (ADS)

Juliana D., Feldhacker

The complex nature of many astrodynamic systems often leads to high computational costs or degraded accuracy in the analysis and design of spacecraft missions, and the incorporation of uncertainty into the trajectory optimization process often becomes intractable. This research applies mathematical modeling techniques to reduce computational cost and improve tractability for design, optimization, uncertainty quantication (UQ) and sensitivity analysis (SA) in astrodynamic systems and develops a method for trajectory optimization under uncertainty (OUU). This thesis demonstrates the use of surrogate regression models and polynomial chaos expansions for the purpose of design and UQ in the complex three-body system. Results are presented for the application of the models to the design of mid-eld rendezvous maneuvers for spacecraft in three-body orbits. The models are shown to provide high accuracy with no a priori knowledge on the sample size required for convergence. Additionally, a method is developed for the direct incorporation of system uncertainties into the design process for the purpose of OUU and robust design; these methods are also applied to the rendezvous problem. It is shown that the models can be used for constrained optimization with orders of magnitude fewer samples than is required for a Monte Carlo approach to the same problem. Finally, this research considers an application for which regression models are not well-suited, namely UQ for the kinetic de ection of potentially hazardous asteroids under the assumptions of real asteroid shape models and uncertainties in the impact trajectory and the surface material properties of the asteroid, which produce a non-smooth system response. An alternate set of models is presented that enables analytic computation of the uncertainties in the imparted momentum from impact. Use of these models for a survey of asteroids allows conclusions to be drawn on the eects of an asteroid's shape on the ability to successfully divert the asteroid via kinetic impactor.

How health systems could avert 'triple fail' events that are harmful, are costly, and result in poor patient satisfaction.

PubMed

Lewis, Geraint; Kirkham, Heather; Duncan, Ian; Vaithianathan, Rhema

2013-04-01

Health care systems in many countries are using the "Triple Aim"--to improve patients' experience of care, to advance population health, and to lower per capita costs--as a focus for improving quality. Population strategies for addressing the Triple Aim are becoming increasingly prevalent in developed countries, but ultimately success will also require targeting specific subgroups and individuals. Certain events, which we call "Triple Fail" events, constitute a simultaneous failure to meet all three Triple Aim goals. The risk of experiencing different Triple Fail events varies widely across people. We argue that by stratifying populations according to each person's risk and anticipated response to an intervention, health systems could more effectively target different preventive interventions at particular risk strata. In this article we describe how such an approach could be planned and operationalized. Policy makers should consider using this stratified approach to reduce the incidence of Triple Fail events, thereby improving outcomes, enhancing patient experience, and lowering costs.

The S(IV)-type Asteroids as Ordinary Chondrite Parent Body Candidates: Implications for the Completeness of the Meteorite Sample of Asteroids

NASA Astrophysics Data System (ADS)

Gaffey, M. J.

1995-09-01

The discrepancy between the abundance of ordinary chondrites (OCs) among the meteorites and the rarity of unambiguously similar assemblages in the asteroid belt has been a major point of discussion within and between the asteroid and meteorite communities. Various resolutions to this apparent paradox have been proposed [e.g., 1-5], including: 1) interpretations of S-type asteroid spectra are incorrect due to space weathering effects; 2) ordinary chondrites derive from a few rare but favorably situated parent bodies; 3) OCs come from a residual population of small unheated mainbelt asteroids; 4) shock effects darken OC parent body surfaces disguising them as C-type asteroids, and 5) OCs come from inner solar system planetesimals ejected to the Oort cloud which have been recently perturbed into Earth-crossing orbits. Although none of these possibilities has yet been rigorously excluded, recent investigations suggest that the resolution of the apparent paradox lies in some combination of the first three options. For option 3, the discovery of a small mainbelt asteroid with an OC-like spectrum indicates OC-assemblages among the smaller mainbelt asteroids [6], although their abundance is still low in the current sample [7]. For option 2, the mineralogical survey indicated that while most S-asteroids could be rigorously excluded on mineralogical criteria, the S(IV) subtype of this class has silicate compositions within the OC range [8]. The S(IV)-objects are concentrated near the 3:1 secular resonance at 2.5 AU providing an efficient escape into Earth-crossing orbits. Unfortunately for a simple resolution of the OC parent body question, S(IV) spectra still exhibit weaker silicate features and redder spectral slopes than OC assemblages. Although significant uncertainties remain, optical alteration of asteroid surfaces interpreted from the Galileo images of Ida and Gaspra may reconcile the mismatch between OC and S(IV) spectra [option 1]. Although only a subset of the S(IV) objects are viable OC-parent bodies [3 Juno, 6 Hebe, and 7 Iris are the leading candidates], their proximity to the 3:1 chaotic zone would allow them to contribute a significant portion of the ordinary chondrites. In particular, dynamical models suggest that Hebe should be a major contributor to the terrestrial meteorite flux [9]. Each leading contender is currently undergoing detailed spectral evaluation as a potential OC source. From both asteroid observational constraints and from chemical and isotopic studies of meteorites, the ordinary chondrites appear to represent an extensive and relatively complete (by meteoritic standards) sample of a few asteroid source bodies. In a similar fashion, the Howardite-Eucrite-Diogenite suite sample a single primary parent body (Vesta) and are over-represented in meteorite collections due to a fortuitous (and temporary on a solar system timescale) emplacement of Vesta ejecta fragments close to the 3:1 resonance. This suggests that the particular value of the ordinary chondrites lies in the good sample provided for each source body rather than as representatives of an abundant asteroid type. Acknowledgments: Various portions of this research were supported by NASA Planetary Geology and Geophysics grant NAGW-642 and NSF Planetary Astronomy grant AST-9012180. References: [1] Wetherill G. W. and Chapman C. R. (1988) in Meteorites and the Early Solar System, pp. 35-67, Univ. of Arizona. [2] Bell J. F. et al. (1989) in Asteroids II, pp. 921-945, Univ. of Arizona. [3] Gaffey M. J. et al. (1989) in Asteroids II, pp. 98-127, Univ. of Arizona. [4] Britt D. T. and Pieters C. M. (1991) LPS XXII, 141-142. [5] Gaffey M. J. (1984) Icarus, 60, 83-114. [6] Binzel R. P. et al. (1993) Science, 262, 1541-1543. [7] Shui X. et al. (1995) Icarus, 115, 1-35. [8] Gaffey M. J. et al. (1993) Icarus, 106, 573-602. [9] Farinella P. et al. (1993) Icarus, 101, 174-187.

(3749) BALAM: A VERY YOUNG MULTIPLE ASTEROID SYSTEM

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

Vokrouhlicky, David, E-mail: vokrouhl@cesnet.c

2009-11-20

Binaries and multiple systems among small bodies in the solar system have received wide attention over the past decade. This is because their observations provide a wealth of data otherwise inaccessible for single objects. We use numerical integration to prove that the multiple asteroid system (3749) Balam is very young, in contrast to its previously assumed age of 0.5-1 Gyr related to the formation of the Flora family. This work is enabled by a fortuitous discovery of a paired component to (3749) Balam. We first show that the proximity of the (3749) Balam and 2009 BR60 orbits is not amore » statistical fluke of otherwise quasi-uniform distribution. Numerical integrations then strengthen the case and allow us to prove that 2009 BR60 separated from the Balam system less than a million years ago. This is the first time the age of a binary asteroid can be estimated with such accuracy.« less

Near-Earth Asteroid Tracking (NEAT): First Year Results

NASA Astrophysics Data System (ADS)

Helin, E. F.; Rabinowitz, D. L.; Pravdo, S. H.; Lawrence, K. J.

1997-07-01

The successful detection of Near-Earth Asteroids (NEAs) has been demonstrated by the Near-Earth Asteroid Tracking (NEAT) program at the Jet Propulsion Laboratory during its first year of operation. The NEAT CCD camera system is installed on the U. S. Air Force 1-m GEODSS telescope in Maui. Using state-of-the-art software and hardware, the system initiates nightly transmitted observing script from JPL, moves the telescopes for successive exposures of the selected fields, detects moving objects as faint as V=20.5 in 40 s exposures, determines their astrometric positions, and downloads the data for review at JPL in the morning. The NEAT system is detecting NEAs larger than 200m, comets, and other unique objects at a rate competitive with current operating systems, and bright enough for important physical studies on moderate-sized telescopes. NEAT has detected over 10,000 asteroids over a wide range of magnitudes, demonstrating the excellent capability of the NEAT system. Fifty-five percent of the detections are new objects and over 900 of them have been followed on a second night to receive designation from the Minor Planet Center. 14 NEAs (9 Amors, 4 Apollos, and 1 Aten) have been discovered since March 1996. Also, 2 long period comets and 1996 PW, an asteroidal object with an orbit of a long-period comet, with an eccentricity of 0.992 and orbital period of 5900 years. Program discoveries will be reviewed along with analysis of results pertaining to the discovery efficiency, distribution on the sky, range of orbits and magnitudes. Related abstract: Lawrence, K., et al., 1997 DPS

ScienceCast 106: Big Asteroid Flyby

NASA Image and Video Library

2013-05-30

NASA is tracking a large near-Earth asteroid as it passes by the Earth-Moon system on May 31st. Amateur astronomers in the northern hemisphere may be able to see the space rock for themselves during the 1st week of June.

Deep Space Gateway "Recycler" Mission

NASA Astrophysics Data System (ADS)

Graham, L.; Fries, M.; Hamilton, J.; Landis, R.; John, K.; O'Hara, W.

2018-02-01

Use of the Deep Space Gateway provides a hub for a reusable planetary sample return vehicle for missions to gather star dust as well as samples from various parts of the solar system including main belt asteroids, near-Earth asteroids, and Mars moon.

Low-Resolution Spectroscopy of Primitive Asteroids: Progress Report for SARA/VSU Survey

NASA Technical Reports Server (NTRS)

Leake, M. A.; Nogues, J. P.; Gaines, J. K.; Looper, J. K.; Freitas, K. A.

2001-01-01

Progress on a low-resolution survey of primitive C-class asteroids continues using new equipment (and its associated problems) to understand aqueous alteration in the solar system. Additional information is contained in the original extended abstract.

Science Experiments of a Jupiter Trojan asteroid in the Solar Power Sail Mission

NASA Astrophysics Data System (ADS)

Okada, T.; Kebukawa, Y.; Aoki, J.; Kawai, Y.; Ito, M.; Yano, H.; Okamoto, C.; Matsumoto, J.; Bibring, J. P.; Ulamec, S.; Jaumann, R.; Iwata, T.; Mori, O.; Kawaguchi, J.

2017-12-01

A Jupiter Trojan asteroid mission using a large area solar power sail (SPS) is under study in JAXA in collaboration with DLR and CNES. The asteroid will be investigated through remote sensing, followed by in situ in-depth observations on the asteroid with a lander. A sample-return is also studied as an option. LUCY has been selected as the NASA's future Discovery class mission which aims at understanding the diversity of Jupiter Trojans by multiple flybys, complementally to the SPS mission. The SPS is a candidate of the next medium class space science mission in Japan. The 1.4-ton spacecraft will carry a 100-kg class lander and 20-kg mission payloads on it. Its launch is expected in mid 2020s, and will take at least 11 years to visit a Jupiter Trojan asteroid. During the cruise phase, science experiments will be performed such as an infrared astronomy, a very long baseline gamma ray interferometry, and dust and magnetic field measurements. A classical static model of solar system suggests that the Jupiter Trojans were formed around the Jupiter region, while a dynamical model such as Nice model indicates that they formed at the far end of the solar system and then scattered inward due to a dynamical migration of giant planets. The physical, mineralogical, organics and isotopic distribution in the heliocentric distance could solve their origin and evolution of the solar system. A global mapping of the asteroid from the mothership will be conducted such as high-resolved imaging, NIR and TIR imaging spectrometry, and radar soundings. The lander will characterize the asteroid with geological, mineralogical, and geophysical observations using a panoramic camera, an infrared hyperspectral imager, a magnetometer, and a thermal radiometer. These samples will be measured by a high resolved mass spectrometer (HRMS) to investigate isotopic ratios of hydrogen, nitrogen, oxygen, as well as organic species.

A unique basaltic micrometeorite expands the inventory of solar system planetary crusts

PubMed Central

Gounelle, Matthieu; Chaussidon, Marc; Morbidelli, Alessandro; Barrat, Jean-Alix; Engrand, Cécile; Zolensky, Michael E.; McKeegan, Kevin D.

2009-01-01

Micrometeorites with diameter ≈100–200 μm dominate the flux of extraterrestrial matter on Earth. The vast majority of micrometeorites are chemically, mineralogically, and isotopically related to carbonaceous chondrites, which amount to only 2.5% of meteorite falls. Here, we report the discovery of the first basaltic micrometeorite (MM40). This micrometeorite is unlike any other basalt known in the solar system as revealed by isotopic data, mineral chemistry, and trace element abundances. The discovery of a new basaltic asteroidal surface expands the solar system inventory of planetary crusts and underlines the importance of micrometeorites for sampling the asteroids' surfaces in a way complementary to meteorites, mainly because they do not suffer dynamical biases as meteorites do. The parent asteroid of MM40 has undergone extensive metamorphism, which ended no earlier than 7.9 Myr after solar system formation. Numerical simulations of dust transport dynamics suggest that MM40 might originate from one of the recently discovered basaltic asteroids that are not members of the Vesta family. The ability to retrieve such a wealth of information from this tiny (a few micrograms) sample is auspicious some years before the launch of a Mars sample return mission. PMID:19366660

The comet rendezvous asteroid flyby mission to Comet Kopff - Getting there is half the fun

NASA Technical Reports Server (NTRS)

Sweetser, Theodore H.; Kiedron, Krystyna

1990-01-01

The goal of the Comet Rendezvous Asteroid Flyby mission (CRAF) is to fly 'outward to the beginning', to examine closely what are thought to be remnants of the origins of the solar system. In particular, the CRAF spacecraft will use a two-year delta-V-earth-gravity-assist (delta-V-EGA) trajectory to reach a rendezvous point near the aphelion of the Comet Kopff, flying by the asteroid 449 Hamburga on the way. This paper discusses the trajectory used to get to the comet. Topics covered include the launch period, possible additional asteroid flybys, the earth flyby, the Hamburga flyby, and the rendezvous with Comet Kopff.

Meteorite WIS91600: A New Sample Related to a D- or T-type Asteroid

NASA Technical Reports Server (NTRS)

Hiroi, T.; Tonui, E.; Pieters, C. M.; Zolensky, M. E.; Ueda, Y.; Miyamoto, M.; Sasaki, S.

2005-01-01

Since the Tagish Lake meteorite fell in January 2000, the assumed one-of-the-kind meteorite has become the hottest issue among a diversity of scientists. Meanwhile, as the physical origin of the meteorite in our solar system, D or T asteroids have been suggested by Hiroi et al. based on comparison of their visible-near-infrared (VNIR) reflectance spectra. While it is probably still true that the Tagish Lake meteorite is possibly the first recovered sample from a D or T asteroid as a meteorite fall, we report in this paper that the meteorite WIS91600 may actually be the first recovered sample from one of those asteroids as a meteorite find.

Lessons for Interstellar Travel from the Guidance and Control Design of the Near Earth Asteroid Scout Solar Sail Mission

NASA Technical Reports Server (NTRS)

Diedrich, Benjamin; Heaton, Andrew

2017-01-01

NASA's Near Earth Asteroid Scout (NEA Scout) solar sail mission will fly by and image an asteroid. The team has experience characterizing the sail forces and torques used in guidance, navigation, and control to meet the scientific objectives. Interstellar and precursor sail missions similarly require understanding of beam riding dynamics to follow sufficiently accurate trajectories to perform their missions. Objective: Identify the driving factors required to implement a guidance and control system that meets mission requirements for a solar sail mission; Compare experience of an asteroid flyby mission to interstellar missions to flyby and observe other stars or precursor missions to study the extrasolar medium.

The Dipole Segment Model for Axisymmetrical Elongated Asteroids

NASA Astrophysics Data System (ADS)

Zeng, Xiangyuan; Zhang, Yonglong; Yu, Yang; Liu, Xiangdong

2018-02-01

Various simplified models have been investigated as a way to understand the complex dynamical environment near irregular asteroids. A dipole segment model is explored in this paper, one that is composed of a massive straight segment and two point masses at the extremities of the segment. Given an explicitly simple form of the potential function that is associated with the dipole segment model, five topological cases are identified with different sets of system parameters. Locations, stabilities, and variation trends of the system equilibrium points are investigated in a parametric way. The exterior potential distribution of nearly axisymmetrical elongated asteroids is approximated by minimizing the acceleration error in a test zone. The acceleration error minimization process determines the parameters of the dipole segment. The near-Earth asteroid (8567) 1996 HW1 is chosen as an example to evaluate the effectiveness of the approximation method for the exterior potential distribution. The advantages of the dipole segment model over the classical dipole and the traditional segment are also discussed. Percent error of acceleration and the degree of approximation are illustrated by using the dipole segment model to approximate four more asteroids. The high efficiency of the simplified model over the polyhedron is clearly demonstrated by comparing the CPU time.

Integrated Attitude Control Strategy for the Asteroid Redirect Mission

NASA Technical Reports Server (NTRS)

Lopez, Pedro, Jr.; Price, Hoppy; San Martin, Miguel

2014-01-01

A deep-space mission has been proposed to redirect an asteroid to a distant retrograde orbit around the moon using a robotic vehicle, the Asteroid Redirect Vehicle (ARV). In this orbit, astronauts will rendezvous with the ARV using the Orion spacecraft. The integrated attitude control concept that Orion will use for approach and docking and for mated operations will be described. Details of the ARV's attitude control system and its associated constraints for redirecting the asteroid to the distant retrograde orbit around the moon will be provided. Once Orion is docked to the ARV, an overall description of the mated stack attitude during all phases of the mission will be presented using a coordinate system that was developed for this mission. Next, the thermal and power constraints of both the ARV and Orion will be discussed as well as how they are used to define the optimal integrated stack attitude. Lastly, the lighting and communications constraints necessary for the crew's extravehicular activity planned to retrieve samples from the asteroid will be examined. Similarly, the joint attitude control strategy that employs both the Orion and the ARV attitude control assets prior, during, and after each extravehicular activity will also be thoroughly discussed.

Alien Asteroid Belt Compared to our Own

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site] Figure 1: Band of Light Comparison

This artist's concept illustrates what the night sky might look like from a hypothetical alien planet in a star system with an asteroid belt 25 times as massive as the one in our own solar system (alien system above, ours below; see Figure 1).

NASA's Spitzer Space Telescope found evidence for such a belt around the nearby star called HD 69830, when its infrared eyes spotted dust, presumably from asteroids banging together. The telescope did not find any evidence for a planet in the system, but astronomers speculate one or more may be present.

The movie begins at dusk on the imaginary world, when HD 69830, like our Sun, has begun to set over the horizon. Time is sped up to show the onset of night and the appearance of a brilliant band of light. This light comes from dust in a massive asteroid belt, which scatters sunlight.

In our solar system, anybody observing the skies on a moonless night far from city lights can see the sunlight that is scattered by dust in our asteroid belt. Called zodiacal light and sometimes the 'false dawn,' this light appears as a dim band stretching up from the horizon when the Sun is about to rise or set. The light is faint enough that the disk of our Milky Way galaxy remains the most prominent feature in the sky. (The Milky Way disk is shown perpendicular to the zodiacal light in both pictures.)

In contrast, the zodiacal light in the HD 69830 system would be 1,000 times brighter than our own, outshining even the Milky Way.

Tidal and Dynamical Evolution of Binary Asteroids

NASA Astrophysics Data System (ADS)

Jacobson, Seth A.; Scheeres, D. J.

2009-05-01

We derive a realistic model for the evolution of a tidally perturbed binary, using classical theory, to examine the system just after a spin-up fission event. The spin rate of an asteroid can be increased by the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect -- thermal re-radiation from an asymmetric body, which induces torques that can rotationally accelerate the body. If the asteroid is modeled as a "rubble pile", a collection of gravitationally bound gravel with no tensile strength, increasing the spin rate will lead to a fission process that would resemble that of a viscous fluidic body [Holsapple 2007]. However, high-resolution imagery of an asteroid's constituents indicates that there is a significant distribution of size scales. A specific example is the asteroid Itokawa, which appears to be two such rubble piles in contact with each other [Fujiwara 2006]. The shape of these bodies will be irregular (modeled as tri-axial ellipsoids with a gravitational potential expanded up to second order). Their motions will raise tides on the opposing body. These tides will dissipate energy, potentially providing enough energy loss for the system to settle into a stable orbit. Fissioned binary systems are always initially unstable [Scheeres 2009, 2008]. We expect tidal dissipation rates to vary widely during the initial evolution of the system, due to this instability. The model applies instantaneous tidal torques to determine energy loss. Our preliminary results indicate that tidal energy dissipation could relax the system to a state of relative equilibrium on order 100,000 years, creating systems similar to those observed. Holsapple, K. A., Icarus, 187, 2007. Fujiwara, A., Science, 312, 2006. Scheeres, D., CMDA, 2009 (Accepted Jan 10, 2009). Scheeres, D., AAS, DDA meeting #39, #9.01, 2008.

Generalized Calibration of the Polarimetric Albedo Scale of Asteroids

NASA Astrophysics Data System (ADS)

Lupishko, D. F.

2018-03-01

Six different calibrations of the polarimetric albedo scale of asteroids have been published so far. Each of them contains its particular random and systematic errors and yields its values of geometric albedo. On the one hand, this complicates their analysis and comparison; on the other hand, it becomes more and more difficult to decide which of the proposed calibrations should be used. Moreover, in recent years, new databases on the albedo of asteroids obtained from the radiometric surveys of the sky with the orbital space facilities (the InfraRed Astronomical Satellite (IRAS), the Japanese astronomical satellite AKARI (which means "light"), the Wide-field Infrared Survey Explorer (WISE), and the Near-Earth Object Wide-field Survey Explorer (NEOWISE)) have appeared; and the database on the diameters and albedos of asteroids obtained from their occultations of stars has substantially increased. Here, we critically review the currently available calibrations and propose a new generalized calibration derived from the interrelations between the slope h and the albedo and between P min and the albedo. This calibration is based on all of the available series of the asteroid albedos and the most complete data on the polarization parameters of asteroids. The generalized calibration yields the values of the polarimetric albedo of asteroids in the system unified with the radiometric albedos and the albedos obtained from occultations of stars by asteroids. This, in turn, removes the difficulties in their comparison, joint analysis, etc.

Analysis of the orbit of the Centaur asteroid 2009 HW77

NASA Astrophysics Data System (ADS)

Wlodarczyk, I.; Cernis, K.; Eglitis, I.

2011-12-01

We present the time evolution of orbital elements of the Centaur asteroid 2009 HW77, discovered by KC and IE, forwards and backwards in time over a 10-Myr period. The dynamical behaviour is analysed using three software packages: the ORBFIT, the SWIFT and the MERCURY integrators. Changes in the orbital elements of 2009 HW77 clones are calculated using the classification of Horner et al. It is shown that close approaches to the giant planets significantly change the asteroid orbit. Our computations made with the SWIFT software and with the MERCURY software give similar results. The half-life is about 5 Myr in both the forward and backward integrations. Moreover, our computations suggest that the Centaur asteroid will be temporarily locked as a periodic asteroid connected with Jupiter with a Tisserand parameter smaller than 3. Hence it is dynamically similar to the Jupiter Family Comets. The mean duration in this state is about 82 kyr, but the behaviour and lifetime depend on whether capture occurs after a few hundred thousand years or a few hundred million years. Several clones of this dynamically interesting Centaur asteroid are temporarily locked up to four times as periodic asteroids connected with Jupiter, after which they are ejected from the Solar system. According to Bailey and Malhotra, asteroid 2009 HW77 may belong to the diffusing class of Centaurs, which can evolve into Jupiter Family Comets.

Spin rate distribution of small asteroids

NASA Astrophysics Data System (ADS)

Pravec, P.; Harris, A. W.; Vokrouhlický, D.; Warner, B. D.; Kušnirák, P.; Hornoch, K.; Pray, D. P.; Higgins, D.; Oey, J.; Galád, A.; Gajdoš, Š.; Kornoš, L.; Világi, J.; Husárik, M.; Krugly, Yu. N.; Shevchenko, V.; Chiorny, V.; Gaftonyuk, N.; Cooney, W. R.; Gross, J.; Terrell, D.; Stephens, R. D.; Dyvig, R.; Reddy, V.; Ries, J. G.; Colas, F.; Lecacheux, J.; Durkee, R.; Masi, G.; Koff, R. A.; Goncalves, R.

2008-10-01

The spin rate distribution of main belt/Mars crossing (MB/MC) asteroids with diameters 3-15 km 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/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. 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.

Slow Rotating Asteroids: A Long Day's Journey into Night

NASA Astrophysics Data System (ADS)

Warner, Brian D.

2009-05-01

While there is no formal definition of a "slow rotator" among asteroids, anything with a period of at least 24 hours can be considered to be at least at the fast end of the group. These objects are of particular interest to those studying the evolution and dynamics of the asteroids within the solar system for several reasons. Most important among them is to generalize theories regarding the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect, which is the thermal re-radiation of sunlight that can not only affect the orientation of an asteroid's spin axis but its rate of rotation as well. In those cases where the spin rate is decreased, an asteroid can eventually be sent into a state of "tumbling" (NPAR - non-principal axis rotation) that can last for millions of years. However, not all slow rotating asteroids appear to be tumbling. This is not expected and so careful studies of these objects are needed to determine if this is really the case or if the tumbling has reached a condition where the secondary frequency - the precession of the spin axis - has been reduced to near zero. Furthermore, there appears to be an excess of slow rotators among the NEA and inner main-belt populations. Determining whether or not this is true among the broader population of asteroids is also vital to understanding the forces at work among the asteroids.

JOVIAN EARLY BOMBARDMENT: PLANETESIMAL EROSION IN THE INNER ASTEROID BELT

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

Turrini, D.; Coradini, A.; Magni, G., E-mail: diego.turrini@ifsi-roma.inaf.it

The asteroid belt is an open window on the history of the solar system, as it preserves records of both its formation process and its secular evolution. The progenitors of the present-day asteroids formed in the Solar Nebula almost contemporary to the giant planets. The actual process producing the first generation of asteroids is uncertain, strongly depending on the physical characteristics of the Solar Nebula, and the different scenarios produce very diverse initial size-frequency distributions (SFDs). In this work, we investigate the implications of the formation of Jupiter, plausibly the first giant planet to form, on the evolution of themore » primordial asteroid belt. The formation of Jupiter triggered a short but intense period of primordial bombardment, previously unaccounted for, which caused an early phase of enhanced collisional evolution in the asteroid belt. Our results indicate that this Jovian Early Bombardment caused the erosion or the disruption of bodies smaller than a threshold size, which strongly depends on the SFD of the primordial planetesimals. If the asteroid belt was dominated by planetesimals less than 100 km in diameter, the primordial bombardment would have caused the erosion of bodies smaller than 200 km in diameter. If the asteroid belt was instead dominated by larger planetesimals, the bombardment would have resulted in the destruction of bodies as big as 500 km.« less

New observations of (4179) Toutatis from the Chang'e-2 flyby mission and future Chinese missions to asteroids

NASA Astrophysics Data System (ADS)

Ji, J.

2014-07-01

Primitive asteroids are remnant building blocks in the Solar System formation. They provide key clues for us to reach in-depth understanding of the process of planetary formation, the complex environment of early Solar nebula, and even the occurrence of life on the Earth. 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 with a smaller lobe (head) and a larger lobe (body). Such bifurcated configuration is indicative of a contact binary origin for Toutatis. In addition, the images with a 3-m resolution or higher provide a number of new discoveries about this asteroid, such as an 800-meter basin at the end of the large lobe, a sharply perpendicular silhouette near the neck region, and direct evidence of boulders and regolith, indicating that Toutatis is probably a rubble-pile asteroid. The Chang'e-2 observations have provided significant new insights into the geological features and the formation and evolution of this asteroid. Moreover, a conceptual introduction to future Chinese missions to asteroids, such as the major scientific objectives, scientific payloads, and potential targets, will be briefly given. The proposed mission will benefit a lot from potential international collaboration in the future.

The planet crossing asteroid survey: Progress in the analysis of populations and terrestrial-planet cratering rates

NASA Technical Reports Server (NTRS)

Helin, E. F.; Dunbar, R. S.

1984-01-01

The Planet-Crossing Asteroid Survey (PCAS) is making steady progress toward the accumulation of the data required to make improved estimates of the populations and cratering rates which can be compared with the existing record of impact events. The PCAS is the chief source of new objects on which to base these calculations over the past decade, and is an integral part of the continuing refinement of the estimates used in planetological applications. An adjunct effort to determine albedo statistics from photometry of UCAS plates is being pursued as well, to better define the magnitude frequency distributions of asteroids. This will improve the quality of the population and collision probability calculations. The survey effort continues to discover new asteroids whose orbital characteristics may reveal the origin and evolution mechanisms reponsible for the transport of the planet-crossing asteroids to the inner solar system.

First known Terrestrial Impact of a Binary Asteroid from a Main Belt Breakup Event

PubMed Central

Ormö, Jens; Sturkell, Erik; Alwmark, Carl; Melosh, Jay

2014-01-01

Approximately 470 million years ago one of the largest cosmic catastrophes occurred in our solar system since the accretion of the planets. A 200-km large asteroid was disrupted by a collision in the Main Asteroid Belt, which spawned fragments into Earth crossing orbits. This had tremendous consequences for the meteorite production and cratering rate during several millions of years following the event. The 7.5-km wide Lockne crater, central Sweden, is known to be a member of this family. We here provide evidence that Lockne and its nearby companion, the 0.7-km diameter, contemporaneous, Målingen crater, formed by the impact of a binary, presumably ‘rubble pile’ asteroid. This newly discovered crater doublet provides a unique reference for impacts by combined, and poorly consolidated projectiles, as well as for the development of binary asteroids. PMID:25340551

Albedos of Small Hilda Asteroids

NASA Astrophysics Data System (ADS)

Ryan, Erin L.; Woodward, C. E.

2010-10-01

We present albedo results for 70 small Hilda dynamical family members detected by the Spitzer Space Telescope in multiple archival programs. This Spitzer data samples Hildas with diameters between 2 and 11 kilometers. Our preliminary analysis reveals that the mean geometric albedo for this sample is pv = 0.05, matching the mean albedo derived for large (20 to 160 km) Hilda asteroids observed by IRAS (Ryan and Woodward 2010). This mean albedo is significantly darker than the mean albedo of asteroids in the outer main belt (2.8 AU < a < 3.5 AU), possibly suggesting that these asteroids did not originate from the outer main belt . This is in direct conflict with some dynamical models which suggest that the HIldas are field asteroids trapped from an inward migration of Jupiter (Franklin et al. 2004), and may provide additional observation support for delivery of dark Kuiper Belt contaminants to the inner solar system as per the Nice Model (Levison et al. 2009).

Secular Resonance Sweeping of the Main Asteroid Belt During Planet Migration

NASA Astrophysics Data System (ADS)

Minton, David A.; Malhotra, Renu

2011-05-01

We calculate the eccentricity excitation of asteroids produced by the sweeping ν6 secular resonance during the epoch of planetesimal-driven giant planet migration in the early history of the solar system. We derive analytical expressions for the magnitude of the eccentricity change and its dependence on the sweep rate and on planetary parameters; the ν6 sweeping leads to either an increase or a decrease of eccentricity depending on an asteroid's initial orbit. Based on the slowest rate of ν6 sweeping that allows a remnant asteroid belt to survive, we derive a lower limit on Saturn's migration speed of ~0.15 AU Myr-1 during the era that the ν6 resonance swept through the inner asteroid belt (semimajor axis range 2.1-2.8 AU). This rate limit is for Saturn's current eccentricity and scales with the square of its eccentricity; the limit on Saturn's migration rate could be lower if its eccentricity were lower during its migration. Applied to an ensemble of fictitious asteroids, our calculations show that a prior single-peaked distribution of asteroid eccentricities would be transformed into a double-peaked distribution due to the sweeping of the ν6 resonance. Examination of the orbital data of main belt asteroids reveals that the proper eccentricities of the known bright (H <= 10.8) asteroids may be consistent with a double-peaked distribution. If so, our theoretical analysis then yields two possible solutions for the migration rate of Saturn and for the dynamical states of the pre-migration asteroid belt: a dynamically cold state (single-peaked eccentricity distribution with mean of ~0.05) linked with Saturn's migration speed ~4 AU Myr-1 or a dynamically hot state (single-peaked eccentricity distribution with mean of ~0.3) linked with Saturn's migration speed ~0.8 AU Myr-1.

Delivery of asteroids and meteorites to the inner solar system

NASA Technical Reports Server (NTRS)

Greenberg, Richard; Nolan, Michael C.

1989-01-01

Two major models of asteroid/meteorite demographics are described and reviewed critically: the collisional model of Greenberg and Chapman (1983), and the orbital evolution model of Wetherill (1985). It is shown that each of the two models tends to gloss over the central processes in the other and tends to ignore (and to some degree violate) the key observables that constrain the other model. The uncertainties that prevent definite acceptance of any particular model for the delivery of asteroidal material to the earth are described.

Dawn : a mission in developement for exploration of main belt asteroids Vesta and Ceres

NASA Technical Reports Server (NTRS)

Rayman, Marc D.; Fraschetti, Thomas C.; Russell, Christopher T.; Raymond, Carol A.

2004-01-01

Dawn is in development for a 2006 launch on a mission to explore main belt asteroids in order to yield insights into important questions about the formation and evolution of the solar system. Its objective is to acquire detailed data from orbit around two complementary bodies, Vesta and Ceres, the two most massive asteroids. The project relies on extensive heritage from other deep-space and Earth-orbiting missions, thus permitting the ambitious objectives to be accomplished with an affordable budget.

PHAROS: Shedding Light on the Near-Earth Asteroid Apophis

NASA Technical Reports Server (NTRS)

Sharma, Jonathan; Lafleur, Jarret; Barron, Kreston; Townley, Jonathan; Shah, Nilesh; Apa, Jillian

2007-01-01

The Pharos mission to asteroid Apophis provides the first major opportunity to enhance orbital state and scientific knowledge of the most threatening Earth-crossing asteroid that has ever been tracked. Pharos aims to accomplish concrete and feasible orbit determination and scientific objectives while achieving balance among mission cost, nsk,and schedule. Similar to its ancient Egyptian namesake, Pharos acts as a beacon shedding light not only on the physical characteristics of Apophis, but also on its state as it travels through the solar system.

Triple loop heat exchanger for an absorption refrigeration system

DOEpatents

Reimann, Robert C.

1984-01-01

A triple loop heat exchanger for an absorption refrigeration system is disclosed. The triple loop heat exchanger comprises portions of a strong solution line for conducting relatively hot, strong solution from a generator to a solution heat exchanger of the absorption refrigeration system, conduit means for conducting relatively cool, weak solution from the solution heat exchanger to the generator, and a bypass system for conducting strong solution from the generator around the strong solution line and around the solution heat exchanger to an absorber of the refrigeration system when strong solution builds up in the generator to an undesirable level. The strong solution line and the conduit means are in heat exchange relationship with each other in the triple loop heat exchanger so that, during normal operation of the refrigeration system, heat is exchanged between the relatively hot, strong solution flowing through the strong solution line and the relatively cool, weak solution flowing through the conduit means. Also, the strong solution line and the bypass system are in heat exchange relationship in the triple loop heat exchanger so that if the normal flow path of relatively hot, strong solution flowing from the generator to an absorber is blocked, then this relatively, hot strong solution which will then be flowing through the bypass system in the triple loop heat exchanger, is brought into heat exchange relationship with any strong solution which may have solidified in the strong solution line in the triple loop heat exchanger to thereby aid in desolidifying any such solidified strong solution.

Asteroids, Comets, Meteors 2014

NASA Astrophysics Data System (ADS)

Muinonen, K.; Penttilä, A.; Granvik, M.; Virkki, A.; Fedorets, G.; Wilkman, O.; Kohout, T.

2014-08-01

Asteroids, Comets, Meteors focuses on the research of small Solar System bodies. Small bodies are the key to understanding the formation and evolution of the Solar System, carrying signals from pre-solar times. Understanding the evolution of the Solar System helps unveil the evolution of extrasolar planetary systems. Societally, small bodies will be important future resources of minerals. The near-Earth population of small bodies continues to pose an impact hazard, whether it be small pieces of falling meteorites or larger asteroids or cometary nuclei capable of causing global environmental effects. The conference series entitled ''Asteroids, Comets, Meteors'' constitutes the leading international series in the field of small Solar System bodies. The first three conferences took place in Uppsala, Sweden in 1983, 1985, and 1989. The conference is now returning to Nordic countries after a quarter of a century. After the Uppsala conferences, the conference has taken place in Flagstaff, Arizona, U.S.A. in 1991, Belgirate, Italy in 1993, Paris, France in 1996, Ithaca, New York, U.S.A. in 1999, in Berlin, Germany in 2002, in Rio de Janeiro, Brazil in 2005, in Baltimore, Maryland, U.S.A. in 2008, and in Niigata, Japan in 2012. ACM in Helsinki, Finland in 2014 will be the 12th conference in the series.

IR lasers in a struggle against dangerous cosmic objects

NASA Astrophysics Data System (ADS)

Kuzyakov, Boris A.

2001-03-01

Humanity can struggle with the small dangerous cosmic objects in our time and its parameter knowledge are needed. A present paper deals with prospects for the perspective of the laser methods applications for a dangerous asteroids discovering and a remote sensing and for the course correction systems of the influence expedients. The cosmic IR lasers will be used for remote sensing measurement of the various cosmic objects parameters: dimensions are more than 50 m, velocity is more than 10 km/s. The laser methods have the good perspectives among a large fleet of diagnostics technical means. The more effective CO2-laser parameters were defined for the solar systems smaller bodies velocity analysis. The laser is supplied with modulated laser radiation and an automatic tuning optical system. The CO2-lidars are needed for the asteroids detections and remote sensing at the distances of 30,000 km to 1 Mkm. A laser Doppler anemometer method with adaptive selection is used. The power calculations were made for the various asteroids in a cosmic space. The possibilities are estimated for remote sensing and for the course correction systems of the influence expedients also. The such system must be good for the distances nearby 12600 km, as the asteroids velocity can be more than 70 km/s.

Relative Terrain Imaging Navigation (RETINA) Tool for the Asteroid Redirect Robotic Mission (ARRM)

NASA Technical Reports Server (NTRS)

Wright, Cinnamon A.; Van Eepoel, John; Liounis, Andrew; Shoemaker, Michael; DeWeese, Keith; Getzandanner, Kenneth

2016-01-01

As a part of the NASA initiative to collect a boulder off of an asteroid and return it to Lunar orbit, the Satellite Servicing Capabilities Office (SSCO) and NASA GSFC are developing an on-board relative terrain imaging navigation algorithm for the Asteroid Redirect Robotic Mission (ARRM). After performing several flybys and dry runs to verify and refine the shape, spin, and gravity models and obtain centimeter level imagery, the spacecraft will descend to the surface of the asteroid to capture a boulder and return it to Lunar Orbit. The algorithm implements Stereophotoclinometry methods to register landmarks with images taken onboard the spacecraft, and use these measurements to estimate the position and orientation of the spacecraft with respect to the asteroid. This paper will present an overview of the ARRM GN&C system and concept of operations as well as a description of the algorithm and its implementation. These techniques will be demonstrated for the descent to the surface of the proposed asteroid of interest, 2008 EV5, and preliminary results will be shown.

Differentiation of the asteroid Ceres as revealed by its shape.

PubMed

Thomas, P C; Parker, J Wm; McFadden, L A; Russell, C T; Stern, S A; Sykes, M V; Young, E F

2005-09-08

The accretion of bodies in the asteroid belt was halted nearly 4.6 billion years ago by the gravitational influence of the newly formed giant planet Jupiter. The asteroid belt therefore preserves a record of both this earliest epoch of Solar System formation and variation of conditions within the solar nebula. Spectral features in reflected sunlight indicate that some asteroids have experienced sufficient thermal evolution to differentiate into layered structures. The second most massive asteroid--4 Vesta--has differentiated to a crust, mantle and core. 1 Ceres, the largest and most massive asteroid, has in contrast been presumed to be homogeneous, in part because of its low density, low albedo and relatively featureless visible reflectance spectrum, similar to carbonaceous meteorites that have suffered minimal thermal processing. Here we show that Ceres has a shape and smoothness indicative of a gravitationally relaxed object. Its shape is significantly less flattened than that expected for a homogeneous object, but is consistent with a central mass concentration indicative of differentiation. Possible interior configurations include water-ice-rich mantles over a rocky core.

The Explored Asteroids: Science and Exploration in the Space Age

NASA Astrophysics Data System (ADS)

Sears, D. W. G.

2015-11-01

Interest in asteroids is currently high in view of their scientific importance, the impact hazard, and the in situ resource opportunities they offer. They are also a case study of the intimate relationship between science and exploration. A detailed review of the twelve asteroids that have been visited by eight robotic spacecraft is presented here. While the twelve explored asteroids have many features in common, like their heavily cratered and regolith covered surfaces, they are a remarkably diverse group. Some have low-eccentricity orbits in the main belt, while some are potentially hazardous objects. They range from dwarf planets to primary planetesimals to fragments of larger precursor objects to tiny shards. One has a moon. Their surface compositions range from basaltic to various chondrite-like compositions. Here their properties are reviewed and what was confirmed and what was newly learned is discussed, and additionally the explored asteroids are compared with comets and meteorites. Several topics are developed. These topics are the internal structure of asteroids, water distribution in the inner solar system and its role in shaping surfaces, and the meteoritic links.

MASCOT2, a Lander to Characterize the Target of an Asteroid Kinetic Impactor Deflection Test (AIM) Mission

NASA Astrophysics Data System (ADS)

Biele, J.; Ulamec, S.; Krause, C.; Cozzoni, B.; Lange, C.; Grundmann, J. T.; Grimm, C.; Ho, T.-M.; Herique, A.; Plettemeier, D.; Grott, M.; Auster, H.-U.; Hercik, D.; Carnelli, I.; Galvez, A.; Philippe, C.; Küppers, M.; Grieger, B.; Gil Fernandez, J.; Grygorczuk, J.

2017-09-01

In the course of the AIDA/AIM mission studies [1,2] a lander, MASCOT2, has been studied to be deployed on the moon of the binary Near-Earth Asteroid system, (65803) Didymos. The AIDA technology demonstration mission, composed of a kinetic impactor, DART, and an observing spacecraft, AIM, has been designed to deliver vital data to determine the momentum transfer efficiency of the kinetic impact and key physical properties of the target asteroid. This will enable derivation of the impact response of the object as a function of its physical properties, a crucial quantitative point besides the qualitative proof that the asteroid has been deflected at all. A landed asset on the target asteroid greatly supports analyzing its dynamical state, mass, geophysical properties, surface and subsurface structure. The lander's main instrument is a bistatic, low frequency radar (LFR) [3a,b] to sound the interior structure of the asteroid. It is supported by a camera (MasCAM) [4], a radiometer (MARA)[5], an accelerometer (DACC [9]), and, optionally regarding the science case, also a magnetometer (MasMAG)[6].

Spectral Characteristics of Hayabusa 2 Near-Earth Asteroid Targets 162173 1999 JU3 and 2001 QC34

NASA Astrophysics Data System (ADS)

Vilas, Faith

2008-04-01

Reflectance spectra of C-type near-Earth asteroid 162173 1999 JU3 were acquired on UT 2007 July 11, September 10 and 11. An absorption feature centered near 0.7 μm, and associated with the presence of iron-bearing phyllosilicates, is seen in the 2007 July 11 spectrum. The 2007 September spectrum shows a shallow absorption feature centered near 0.6 μm. In contrast, the reflectance spectrum of 162173 1999 JU3 obtained during its discovery apparition has no absorption feature, suggesting that the asteroid's surface covers the conjunction of two different geological units. The variation in the presence and absence of these features in reflectance spectra of the surface material of C-type asteroids is observed among main-belt asteroids. As the target for the planned Japanese mission Hayabusa 2, 162173 1999 JU3 could represent a sample of aqueously altered early solar system material. An alternative target for Hayabusa 2, 2001 QC34, was observed spectrally for the first time. Its reflectance spectrum has characteristics of a Q-class or O-class asteroid.

Thermal History of Near-Earth Asteroids: Implications for OSIRIS-REx Asteroid Sample Return

NASA Astrophysics Data System (ADS)

Springmann, Alessondra; Lauretta, Dante S.

2016-10-01

The connection between orbital and temperature history of small Solar System bodies has only been studied through modeling. The upcoming OSIRIS-REx asteroid sample return mission provides an opportunity to connect thermal modeling predictions with laboratory studies of meteorites to predict past heating and thus dynamical histories of bodies such as OSIRIS-REx mission target asteroid (101955) Bennu. Bennu is a desirable target for asteroid sample return due to its inferred primitive nature, likely 4.5 Gyr old, with chemistry and mineralogy established in the first 10 Myr of solar system history (Lauretta et al. 2015). Delbo & Michel (2011) studied connections between the temperature and orbital history of Bennu. Their results suggest that the surface of Bennu (assuming no regolith turnover) has a 50% probability of being heated to 500 K in the past. Further, the Delbo & Michel simulations show that the temperature within the asteroid below the top layer of regolith could remain at temperatures ~100 K below that of the surface. The Touch-And-Go Sample Acquisition Mechanism on OSIRIS-REx could access both the surface and near surface regolith, collecting primitive asteroid material for study in Earth-based laboratories in 2023. To quantify the effects of thermal metamorphism on the Bennu regolith, laboratory heating experiments on carbonaceous chondrite meteorites with compositions likely similar to that of Bennu were conducted from 300-1200 K. These experiments show mobilization and volatilization of a suite of labile elements (sulfur, mercury, arsenic, tellurium, selenium, antimony, and cadmium) at temperatures that could be reached by asteroids that cross Mercury's orbit. We are able to quantify element loss with temperature for several carbonaceous chondrites and use these results to constrain past orbital histories of Bennu. When OSIRIS-REx samples arrive for analysis we will be able to measure labile element loss in the material, determine maximum past temperature of the samples, and predict the past orbital and thermal history of Bennu.

UV Reflectance of Jupiter's Moon Europa and Asteroid (16) Psyche

NASA Astrophysics Data System (ADS)

Becker, T. M.; Retherford, K. D.; Roth, L.; Hendrix, A.; McGrath, M. A.; Cunningham, N.; Feaga, L. M.; Saur, J.; Elkins-Tanton, L. T.; Walhund, J. E.; Molyneux, P.

2017-12-01

Surface reflectance observations of solar system objects in the UV are not only complimentary to longer wavelength observations for identifying surface composition, but can also reveal new and meaningful information about the surfaces of those bodies. On Europa, far-UV (FUV) spectral observations made by the Hubble Space Telescope (HST) show that the surface lacks a strong water ice absorption edge near 165 nm, which is intriguing because such a band has been detected on most icy satellites. This may suggest that radiolytic processing by Jupiter's magnetosphere has altered the surface, causing absorption at wavelengths longward of the H2O edge, masking this feature. Additionally, the FUV spectra are blue (increasing albedo with shorter wavelengths), and regions that are observed to be dark in the visible appear bright in the FUV. This spectral inversion, also observed on the Moon and some asteroids, may provide insight into the properties of the surface material and how they are processed.We also explore the UV reflectance spectra of the main belt asteroid (16) Psyche. This asteroid is believed to be the metallic remnant core of a differentiated asteroid, stripped of its mantle through collisions. However, there is speculation that the asteroid could have formed as-is from highly reduced metal-rich material near the Sun early in the formation of the solar system. Further, spectral observations in the infrared have revealed pyroxene and hydroxyl on the asteroid's surface, complicating the interpretation that (16) Psyche is a pure metallic object. Laboratory studies indicate that there are diagnostic spectral features in the UV that could be useful for determining the surface composition. We obtained HST observations of Psyche from 160 - 300 nm. Preliminary results show a featureless, red-sloped spectrum, inconsistent with significant amounts of pyroxene on the surface. We will present the spectra of Europa and the asteroid (16) Psyche and discuss the unique details unveiled by studies of these objects in the UV.

Uninterrupted optical light curves of main-belt asteroids from the K2 mission

NASA Astrophysics Data System (ADS)

Szabó, R.; Pál, A.; Sárneczky, K.; Szabó, Gy. M.; Molnár, L.; Kiss, L. L.; Hanyecz, O.; Plachy, E.; Kiss, Cs.

2016-11-01

Context. Because the second reaction wheel failed, a new mission was conceived for the otherwise healthy Kepler space telescope. In the course of the K2 mission, the telescope is staring at the plane of the Ecliptic. Thousands of solar system bodies therefore cross the K2 fields and usually cause additional noise in the highly accurate photometric data. Aims: We here follow the principle that some person's noise is another person's signal and investigate the possibility of deriving continuous asteroid light curves. This is the first such endeavor. In general, we are interested in the photometric precision that the K2 mission can deliver on moving solar system bodies. In particular, we investigate space photometric optical light curves of main-belt asteroids. Methods: We studied the K2 superstamps that cover the fields of M35, and Neptune together with Nereid, which were observed in the long-cadence mode (29.4 min sampling). Asteroid light curves were generated by applying elongated apertures. We used the Lomb-Scargle method to determine periodicities that are due to rotation. Results: We derived K2 light curves of 924 main-belt asteroids in the M35 field and 96 in the path of Neptune and Nereid. The light curves are quasi-continuous and several days long. K2 observations are sensitive to longer rotational periods than typical ground-based surveys. Rotational periods are derived for 26 main-belt asteroids for the first time. The asteroid sample is dominated by faint objects (>20 mag). Owing to the faintness of the asteroids and the high density of stars in the M35 field, only 4.0% of the asteroids with at least 12 data points show clear periodicities or trends that signal a long rotational period, as opposed to 15.9% in the less crowded Neptune field. We found that the duty cycle of the observations had to reach 60% to successfully recover rotational periods. Full Tables 1-4 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/596/A40

Water in the early solar system: Mid-infrared studies of aqueous alteration on asteroids.

NASA Astrophysics Data System (ADS)

McAdam, Margaret M.; Sunshine, Jessica M.; Kelley, Michael S.; Trilling, David E.

2017-10-01

This work investigates the distribution of water in the early Solar System by connecting asteroids to carbonaceous chondrite meteorites using spectroscopy. Aqueous alteration or the chemical reaction between liquid water and silicates on the parent asteroid, has extensively affected several groups of carbonaceous chondrites. The degree of alteration or amount of hydrated minerals produced depends on a number of factors including the abundance of coaccreted water-ice, the internal distribution of water in the parent body and the setting of alteration (e.g., open vs. closed setting). Despite this complexity which is still under investigation, the mineralogical changes produced by aqueous alteration are well understood (e.g., Howard et al., 2015). The mid-infrared spectral region has been shown to be a tool for estimating the degree of alteration of asteroids and meteorites remotely (McAdam et al., 2015). Specifically, mid-infrared spectral features changes continuously with degree of alteration. In this region meteorites can be categorized into four groups based on their spectral characteristics: anhydrous, less altered, intermediately altered and highly altered. We present the estimated degrees of alteration for 73 main belt asteroids using these results. Hydrated minerals appear to be widespread in the main belt and asteroids have variable degrees of alteration. There does not appear to be any relationship between the estimated degree of alteration and size, albedo or heliocentric distance. This indicates that water-ice must have been a significant component of the solar nebula in the 2-5 AU region during the time of carbonaceous chondrite accretion (~2.7-4 Ma post-CAI formation; Sugiura and Fujiya, 2014). The snow-line therefore must have been in this region during this epoch. Furthermore, local heterogeneities of water-ice were likely common since asteroids of all sizes and heliocentric distances may exhibit any degree from anhydrous to highly altered. Additionally, asteroids that have been shown to have water-ice on their surfaces (e.g., Takir and Emery, 2012) appear to have hydrated minerals. This indicates that while these asteroids have water-ice, its presence did not prevent aqueous alteration.

Asteroid clusters similar to asteroid pairs

NASA Astrophysics Data System (ADS)

Pravec, Petr; Vokrouhlicky, David; Fatka, Petr; Kusnirák, Peter; Hornoch, Kamil; Galád, Adrián

2016-10-01

We study five small, tight and young clusters of asteroids. They are placed around following largest (primary) bodies: (11842) Kap'bos, (14627) Emilkowalski, (16598) 1992 YC2, (21509) Lucascavin and (39991) 1998 HR37. Each cluster has 2-4 secondaries that are tightly clustered around the primary body, with distance in the 5-dimensional space of mean orbital elements mostly within 10 m/s, and always < 23 m/s. Backward orbital integrations indicate that they formed between 105 and 106 yr ago. In the P1-q space, where P1 is the primary's spin period and q = Σ Mj/M1 is the total secondary-to-primary mass ratio, the clusters lie in the same range as asteroid pairs formed by rotational fission. We have extended the model of a proto-system separation after rotational fission by Pravec et al. (2010) for application to systems with more than one secondary and found a perfect match for the five tight clusters. We find these clusters to be similar to asteroid pairs and we suggest that they are "extended pairs", having 2-4 escaped secondaries rather than just one secondary as in the case of an asteroid pair. We compare them to six young mini-families (1270) Datura, (2384) Schulhof, (3152) Jones, (6825) Irvine, (10321) Rampo and (20674) 1999 VT1. These mini-families have similar ages, but they have a higher number of members and/or they show a significantly larger spread in the mean orbital elements (dmean on an order of tens m/s) than the five tight clusters. In the P1-q space, all but one of the mini-families lie in the same range as asteroid pairs and the tight clusters; the exception is the mini-family of (3152) Jones which appears to be a collisional family. A possibility that the other five mini-families were also formed by rotational fission as we suggest for the tight clusters ("extended asteroid pairs") is being explored.Reference:Pravec, P., et al. Formation of asteroid pairs by rotational fission. Nature 466, 1085-1088.

Asteroid Evolution: Role of geotechnical properties

NASA Astrophysics Data System (ADS)

Sanchez Lana, Diego P.

2015-08-01

Over the last decade of Planetary research, the scientific community has made many advances in their understanding of the evolution of asteroids in the Solar System. One particular area of fruitful study started with the bold idea that these small planetary bodies could be gravitational aggregates and initially motivated by several different observations and early simulations.If we start with the idea that asteroids are aggregates of different sized components, and not singular monolithic bodies, it is possible to study them with some of the tools that have been used in the fields of Soil Mechanics and Granular Dynamics. In them, parameters such as porosity, cohesive and tensile strength, angles of friction and repose, particle size distributions, stress states, heterogeneity and yield criteria among others, determine how these granular systems will react when subjected to different, changing, external factors. These external factors are believed to have produced and shaped the asteroids that now exist around us and include solar photon momentum, gravitational tides, micro- and macro-impacts and internal energy dissipation.In this presentation we will review what is known about the surface and interiors of rubble pile asteroids, how different theoretical, experimental and simulation tools have been used to study them, how space mission and ground-based observations have shaped our understanding of their physical reality, and what we expect to learn from future missions. The talk will also touch on some of the latest findings obtained by different groups. In particular we will discuss the rotational evolution of self-gravitating aggregates under the influence of the YORP effect and how their angles of friction, tensile strength, porosity, internal structure and density give rise to different disruption modes and the role they play in the formation of asteroids pairs, tumblers and binary systems.

Touch And Go Camera System (TAGCAMS) for the OSIRIS-REx Asteroid Sample Return Mission

NASA Astrophysics Data System (ADS)

Bos, B. J.; Ravine, M. A.; Caplinger, M.; Schaffner, J. A.; Ladewig, J. V.; Olds, R. D.; Norman, C. D.; Huish, D.; Hughes, M.; Anderson, S. K.; Lorenz, D. A.; May, A.; Jackman, C. D.; Nelson, D.; Moreau, M.; Kubitschek, D.; Getzandanner, K.; Gordon, K. E.; Eberhardt, A.; Lauretta, D. S.

2018-02-01

NASA's OSIRIS-REx asteroid sample return mission spacecraft includes the Touch And Go Camera System (TAGCAMS) three camera-head instrument. The purpose of TAGCAMS is to provide imagery during the mission to facilitate navigation to the target asteroid, confirm acquisition of the asteroid sample, and document asteroid sample stowage. The cameras were designed and constructed by Malin Space Science Systems (MSSS) based on requirements developed by Lockheed Martin and NASA. All three of the cameras are mounted to the spacecraft nadir deck and provide images in the visible part of the spectrum, 400-700 nm. Two of the TAGCAMS cameras, NavCam 1 and NavCam 2, serve as fully redundant navigation cameras to support optical navigation and natural feature tracking. Their boresights are aligned in the nadir direction with small angular offsets for operational convenience. The third TAGCAMS camera, StowCam, provides imagery to assist with and confirm proper stowage of the asteroid sample. Its boresight is pointed at the OSIRIS-REx sample return capsule located on the spacecraft deck. All three cameras have at their heart a 2592 × 1944 pixel complementary metal oxide semiconductor (CMOS) detector array that provides up to 12-bit pixel depth. All cameras also share the same lens design and a camera field of view of roughly 44° × 32° with a pixel scale of 0.28 mrad/pixel. The StowCam lens is focused to image features on the spacecraft deck, while both NavCam lens focus positions are optimized for imaging at infinity. A brief description of the TAGCAMS instrument and how it is used to support critical OSIRIS-REx operations is provided.

Stable Algorithm For Estimating Airdata From Flush Surface Pressure Measurements

NASA Technical Reports Server (NTRS)

Whitmore, Stephen, A. (Inventor); Cobleigh, Brent R. (Inventor); Haering, Edward A., Jr. (Inventor)

2001-01-01

An airdata estimation and evaluation system and method, including a stable algorithm for estimating airdata from nonintrusive surface pressure measurements. The airdata estimation and evaluation system is preferably implemented in a flush airdata sensing (FADS) system. The system and method of the present invention take a flow model equation and transform it into a triples formulation equation. The triples formulation equation eliminates the pressure related states from the flow model equation by strategically taking the differences of three surface pressures, known as triples. This triples formulation equation is then used to accurately estimate and compute vital airdata from nonintrusive surface pressure measurements.

The Rotational Properties of Multi-tailed Asteroid P/2013 P5

NASA Astrophysics Data System (ADS)

Gustafsson, Annika; Moskovitz, Nicholas; Levine, Stephen

2014-11-01

To date, there are twelve known celestial bodies in the Solar System, labeled Main Belt Comets (e.g. Hsieh & Jewitt, 2006) or Active Asteroids (Jewitt, 2012) that exhibit both asteroid and comet-like properties. Among them is P/2013 P5, a comet-asteroid transition object discovered by PAN-STARRS in August 2013. Observations made with the Hubble Space Telescope in September 2013 revealed that P/2013 P5 appears to have six comet-like dust tails. Jewitt et al. (2013) concluded that this extraordinary structure and activity cannot be explained by traditional near-surface ice sublimation or collision events ejecting particles from the asteroid’s surface. Instead, the most likely explanation is that this unusual object has been spun-up by YORP torques to a critical limit that has resulted in the rotational disruption of the asteroid causing the unique six-tail structure. This interpretation predicts that the nucleus of this comet-like asteroid should be in rapid rotation. In November 2013, broadband photometry of P/2013 P5 was obtained with Lowell Observatory’s 4-meter Discovery Channel Telescope using the Large Monolithic Imager to investigate the possibility of rapid rotation. On chip optimal aperture photometry was performed on P/2013 P5. At an apparent magnitude V=22.5 magnitude, we found no significant variability in the light curve at the level of 0.15 magnitudes. General morphology changes in the nucleus-coma system of the asteroid were also investigated. We will present our analysis of this search for variability in both time and spatially across the coma relative to the object’s center of brightness. Hsieh, H. H., & Jewitt, D. 2006, Science, 312, 561Jewitt, D. 2012, AJ, 143, 66Jewitt, D.C., Agarwal, J., Weaver, H., Mutchler, M., & Larson, S. 2013, ApL, 778

Asteroid clusters similar to asteroid pairs

NASA Astrophysics Data System (ADS)

Pravec, P.; Fatka, P.; Vokrouhlický, D.; Scheeres, D. J.; Kušnirák, P.; Hornoch, K.; Galád, A.; Vraštil, J.; Pray, D. P.; Krugly, Yu. N.; Gaftonyuk, N. M.; Inasaridze, R. Ya.; Ayvazian, V. R.; Kvaratskhelia, O. I.; Zhuzhunadze, V. T.; Husárik, M.; Cooney, W. R.; Gross, J.; Terrell, D.; Világi, J.; Kornoš, L.; Gajdoš, Š.; Burkhonov, O.; Ehgamberdiev, Sh. A.; Donchev, Z.; Borisov, G.; Bonev, T.; Rumyantsev, V. V.; Molotov, I. E.

2018-04-01

We studied the membership, size ratio and rotational properties of 13 asteroid clusters consisting of between 3 and 19 known members that are on similar heliocentric orbits. By backward integrations of their orbits, we confirmed their cluster membership and estimated times elapsed since separation of the secondaries (the smaller cluster members) from the primary (i.e., cluster age) that are between 105 and a few 106 years. We ran photometric observations for all the cluster primaries and a sample of secondaries and we derived their accurate absolute magnitudes and rotation periods. We found that 11 of the 13 clusters follow the same trend of primary rotation period vs mass ratio as asteroid pairs that was revealed by Pravec et al. (2010). We generalized the model of the post-fission system for asteroid pairs by Pravec et al. (2010) to a system of N components formed by rotational fission and we found excellent agreement between the data for the 11 asteroid clusters and the prediction from the theory of their formation by rotational fission. The two exceptions are the high-mass ratio (q > 0.7) clusters of (18777) Hobson and (22280) Mandragora for which a different formation mechanism is needed. Two candidate mechanisms for formation of more than one secondary by rotational fission were published: the secondary fission process proposed by Jacobson and Scheeres (2011) and a cratering collision event onto a nearly critically rotating primary proposed by Vokrouhlický et al. (2017). It will have to be revealed from future studies which of the clusters were formed by one or the other process. To that point, we found certain further interesting properties and features of the asteroid clusters that place constraints on the theories of their formation, among them the most intriguing being the possibility of a cascade disruption for some of the clusters.

Triple Value System Dynamics Modeling to Help Stakeholders Engage with Food-Energy-Water Problems

EPA Science Inventory

Triple Value (3V) Community scoping projects and Triple Value Simulation (3VS) models help decision makers and stakeholders apply systems-analysis methodology to complex problems related to food production, water quality, and energy use. 3VS models are decision support tools that...

ASTEROIDS: Living in the Kingdom of Chaos

NASA Astrophysics Data System (ADS)

Morbidelli, A.

2000-10-01

The existence of chaotic regions in the main asteroid belt, related with the lowest-order mean-motion and secular resonances, has long been known. However, only in the last decade have semi-analytic theories allowed a proper understanding of the chaotic behavior observed in numerical simulations which accurately incorporate the entire planetary system. The most spectacular result has been the discovery that the asteroids in some of these resonance may collide with the Sun on typical time scales of a few million year, their eccentricities being pumped to unity during their chaotic evolution. But the asteroid belt is not simply divided into violent chaotic zones and regular regions. It has been shown that the belt is criss-crossed by a large number of high-order mean-motion resonances with Jupiter or Mars, as well as by `three-body resonances' with Jupiter and Saturn. All these weak resonances cause the slow chaotic drift of the `proper' eccentricities and inclinations. The traces left by this evolution are visible, for example, in the structure of the Eos and Themis asteroid families. Weak chaos may also explain the anomalous dispersion of the eccentricities and inclinations observed in the Flora ``clan." Moreover, due to slow increases in their eccentricities, many asteroids start to cross the orbit of Mars, over a wide range of semimajor axes. The improved knowledge of the asteroid belt's chaotic structure provides, for the first time, an opportunity to build detailed quantitative models of the origin and the orbital distribution of Near-Earth Asteroids and meteorites. In turn, these models seem to imply that the semimajor axes of main-belt asteroids must also slowly evolve with time. For asteroids larger than about 20 km this is due mainly to encounters with Ceres, Pallas, and Vesta, while for smaller bodies the so-called Yarkovsky effect should dominate. Everything moves chaotically in the asteroid belt.

The Double Asteroid Redirection Test (DART)

NASA Astrophysics Data System (ADS)

Rivkin, A.; Cheng, A. F.; Stickle, A. M.; Richardson, D. C.; Barnouin, O. S.; Thomas, C.; Fahnestock, E.

2017-12-01

The Double Asteroid Redirection Test (DART) will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. DART is currently in Preliminary Design Phase ("Phase B"), and is part of the Asteroid Impact and Deflection Assessment (AIDA), a joint ESA-NASA cooperative project. The AIDA target is the near-Earth binary asteroid 65803 Didymos, an S-class system that will make a close approach to Earth in fall 2022. The DART spacecraft is designed to impact the Didymos secondary at 6 km/s and demonstrate the ability to modify its trajectory through momentum transfer. The primary goals of AIDA are (1) perform a full-scale demonstration of the spacecraft kinetic impact technique for deflection of an asteroid; (2) measure the resulting asteroid deflection, by targeting the secondary member of a binary NEO and measuring the resulting changes of the binary orbit; and (3) study hyper-velocity collision effects on an asteroid, validating models for momentum transfer in asteroid impacts. The DART impact on the Didymos secondary will change the orbital period of the binary by several minutes, which can be measured by Earth-based optical and radar observations. The baseline DART mission launches in late 2020 to impact the Didymos secondary in 2022 near the time of its close pass of Earth, which enables an array of ground- and space-based observatories to participate in gathering data. The AIDA project will provide the first measurements of momentum transfer efficiency from hyper-velocity kinetic impact at full scale on an asteroid, where the impact conditions of the projectile are known, and physical properties and internal structures of the target asteroid are characterized or constrained. The DART kinetic impact is predicted to make a crater of 6 to 17 meters diameter, depending on target physical properties, but will also release a large volume of particulate ejecta that may be directly observable from Earth or even resolvable as a coma or an ejecta tail by ground-based telescopes.

A Framework for Inferring Taxonomic Class of Asteroids.

NASA Technical Reports Server (NTRS)

Dotson, J. L.; Mathias, D. L.

2017-01-01

Introduction: Taxonomic classification of asteroids based on their visible / near-infrared spectra or multi band photometry has proven to be a useful tool to infer other properties about asteroids. Meteorite analogs have been identified for several taxonomic classes, permitting detailed inference about asteroid composition. Trends have been identified between taxonomy and measured asteroid density. Thanks to NEOWise (Near-Earth-Object Wide-field Infrared Survey Explorer) and Spitzer (Spitzer Space Telescope), approximately twice as many asteroids have measured albedos than the number with taxonomic classifications. (If one only considers spectroscopically determined classifications, the ratio is greater than 40.) We present a Bayesian framework that provides probabilistic estimates of the taxonomic class of an asteroid based on its albedo. Although probabilistic estimates of taxonomic classes are not a replacement for spectroscopic or photometric determinations, they can be a useful tool for identifying objects for further study or for asteroid threat assessment models. Inputs and Framework: The framework relies upon two inputs: the expected fraction of each taxonomic class in the population and the albedo distribution of each class. Luckily, numerous authors have addressed both of these questions. For example, the taxonomic distribution by number, surface area and mass of the main belt has been estimated and a diameter limited estimate of fractional abundances of the near earth asteroid population was made. Similarly, the albedo distributions for taxonomic classes have been estimated for the combined main belt and NEA (Near Earth Asteroid) populations in different taxonomic systems and for the NEA population specifically. The framework utilizes a Bayesian inference appropriate for categorical data. The population fractions provide the prior while the albedo distributions allow calculation of the likelihood an albedo measurement is consistent with a given taxonomic class. These inputs allows calculation of the probability an asteroid with a specified albedo belongs to any given taxonomic class.

A Spectroscopic and Mineralogical Study of Multiple Asteroid Systems

NASA Astrophysics Data System (ADS)

Lindsay, Sean S.; Emery, J. P.; Marchis, F.; Enriquez, J.; Assafin, M.

2013-10-01

There are currently ~200 identified multiple asteroid systems (MASs). These systems display a large diversity in heliocentric distance, size/mass ratio, system angular momentum, mutual orbital parameters, and taxonomic class. These characteristics are simplified under the nomenclature of Descamps and Marchis (2008), which divides MASs into four types: Type-1 - large asteroids with small satellites; Type-2 - similar size double asteroids; Type-3 - small asynchronous systems; and Type-4 - contact-binary asteroids. The large MAS diversity suggests multiple formation mechanisms are required to understand their origins. There are currently three broad formation scenarios: 1) ejecta from impacts; 2) catastrophic disruption followed by rotational fission; and 3) tidal disruption. The taxonomic class and mineralogy of the MASs coupled with the average density and system angular momentum provide a potential means to discriminate between proposed formation mechanisms. We present visible and near-infrared (NIR) spectra spanning 0.45 - 2.45 μm for 23 Main Belt MASs. The data were primarily obtained using the Southern Astrophysical Research Telescope (SOAR) Goodman High Throughput Spectrograph (August 2011 - July 2012) for the visible data and the InfraRed Telescope Facility (IRTF) SpeX Spectrograph (August 2008 - May 2013) for the IR data. Our data were supplemented using previously published data when necessary. The asteroids' Bus-DeMeo taxonomic classes are determined using the MIT SMASS online classification routines. Our sample includes 3 C-types, 1 X-type, 1 K-type, 1 L-type, 4 V-types, 10 S-types, 2 Sq- or Q-types, and 1 ambiguous classification. We calculate the 1- and 2-μm band centers, depths, and areas to determine the pyroxene mineralogy (molar Fs and Wo) of the surfaces using empirically derived equations. The NIR band analysis allows us to determine the S-type subclasses, S(I) - S(VII), which roughly tracks olivine-pyroxene chemistry. A comparison of the orbital parameters, physical parameters (size, density, and angular momentum), collisional family membership, and taxonomy is presented in an effort to find correlations, which may give insights to how these MASs formation mechanisms.

K2 & Solar System Science

NASA Technical Reports Server (NTRS)

Lissauer, Jack

2015-01-01

All of the fields that K2 observes are near the ecliptic plane in order to minimize the spin-up of the spacecraft in response to the effects of solar irradiation. The fields observed by K2 are thus rich in Solar System objects including planets, asteroids and trans-Neptunian objects (TNOs). K2 has already performed observations of Neptune and its large moon Triton, 68 Trojan and Hilda asteroids, 5 TNOs (including Pluto) and Comet C/2013 A1 (Siding Springs). About 10,000 main-belt asteroids that fell into the pixel masks of stars have been serendipitously observed. Observations of small bodies are especially useful for determining rotation periods. Uranus will be observed in a future campaign (C8), as will many more small Solar System bodies. The status of various K2 Solar System studies will be reviewed and placed within the context of our current knowledge of the objects being observed.

The H and G magnitude system for asteroids

NASA Astrophysics Data System (ADS)

Dymock, R.

2007-12-01

This article is based on a presentation given at the Observers' Workshop held at the Open University in Milton Keynes on 2007 February 24. It can be viewed on the Asteroids and Remote Planets Section website at http://homepage.ntlworld.com/roger.dymock/index.htm

Asteroid Redirect Crewed Mission Nominal Design and Performance

NASA Technical Reports Server (NTRS)

Condon, Gerald; williams, Jacob

2014-01-01

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).

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.

Autonomous vision-based navigation for proximity operations around binary asteroids

NASA Astrophysics Data System (ADS)

Gil-Fernandez, Jesus; Ortega-Hernando, Guillermo

2018-02-01

Future missions to small bodies demand higher level of autonomy in the Guidance, Navigation and Control system for higher scientific return and lower operational costs. Different navigation strategies have been assessed for ESA's asteroid impact mission (AIM). The main objective of AIM is the detailed characterization of binary asteroid Didymos. The trajectories for the proximity operations shall be intrinsically safe, i.e., no collision in presence of failures (e.g., spacecraft entering safe mode), perturbations (e.g., non-spherical gravity field), and errors (e.g., maneuver execution error). Hyperbolic arcs with sufficient hyperbolic excess velocity are designed to fulfil the safety, scientific, and operational requirements. The trajectory relative to the asteroid is determined using visual camera images. The ground-based trajectory prediction error at some points is comparable to the camera Field Of View (FOV). Therefore, some images do not contain the entire asteroid. Autonomous navigation can update the state of the spacecraft relative to the asteroid at higher frequency. The objective of the autonomous navigation is to improve the on-board knowledge compared to the ground prediction. The algorithms shall fit in off-the-shelf, space-qualified avionics. This note presents suitable image processing and relative-state filter algorithms for autonomous navigation in proximity operations around binary asteroids.

Autonomous vision-based navigation for proximity operations around binary asteroids

NASA Astrophysics Data System (ADS)

Gil-Fernandez, Jesus; Ortega-Hernando, Guillermo

2018-06-01

Future missions to small bodies demand higher level of autonomy in the Guidance, Navigation and Control system for higher scientific return and lower operational costs. Different navigation strategies have been assessed for ESA's asteroid impact mission (AIM). The main objective of AIM is the detailed characterization of binary asteroid Didymos. The trajectories for the proximity operations shall be intrinsically safe, i.e., no collision in presence of failures (e.g., spacecraft entering safe mode), perturbations (e.g., non-spherical gravity field), and errors (e.g., maneuver execution error). Hyperbolic arcs with sufficient hyperbolic excess velocity are designed to fulfil the safety, scientific, and operational requirements. The trajectory relative to the asteroid is determined using visual camera images. The ground-based trajectory prediction error at some points is comparable to the camera Field Of View (FOV). Therefore, some images do not contain the entire asteroid. Autonomous navigation can update the state of the spacecraft relative to the asteroid at higher frequency. The objective of the autonomous navigation is to improve the on-board knowledge compared to the ground prediction. The algorithms shall fit in off-the-shelf, space-qualified avionics. This note presents suitable image processing and relative-state filter algorithms for autonomous navigation in proximity operations around binary asteroids.

Water Transport and the Evolution of CM Parent Bodies

NASA Technical Reports Server (NTRS)

Coker, R.; Cohen, B.

2014-01-01

Extraterrestrial water-bearing minerals are of great importance both for understanding the formation and evolution of the solar system and for supporting future human activities in space. Asteroids are the primary source of meteorites, many of which show evidence of an early heating episode and varying degrees of aqueous alteration. The origin and characterization of hydrated minerals (minerals containing H2O or OH) among both the main-belt and near-earth asteroids is important for understanding a wide range of solar system formation and evolutionary processes, as well as for planning for human exploration. Current hypotheses postulate asteroids began as mixtures of water ice and anhydrous silicates. A heating event early in solar system history was then responsible for melting the ice and driving aqueous alteration. The link between asteroids and meteorites is forged by reflectance spectra, which show 3-µm bands indicative of bound OH or H2O on the C-class asteroids, which are believed to be the parent bodies of the carbonaceous chondrites in our collections. The conditions at which aqueous alteration occurred in the parent bodies of carbonaceous chondrites are thought to be well-constrained: at 0-25 C for less than 15 Myr after asteroid formation. In previous models, many scenarios exhibit peak temperatures of the rock and co-existing liquid water in more than 75 percent of the asteroid's volume rising to 150 C and higher, due to the exothermic hydration reactions triggering a thermal runaway effect. However, even in a high porosity, water-saturated asteroid very limited liquid water flow is predicted (distances of 100's nm at most). This contradiction has yet to be resolved. Still, it may be possible for water to become liquid even in the near-surface environment, for a long enough time to drive aqueous alteration before vaporizing or freezing then subliming. Thus, we are using physics- and chemistry-based models that include thermal and fluid transport as well as the effects of relevant chemical reactions, to investigate whether formation of hydrated minerals can occur in the surface and near-surface environments of carbonaceous type asteroids. These models will elucidate how the conditions within the parent body that cause internal aqueous alteration play themselves out at the asteroid's surface. We are using our models to determine whether the heat budget of 20-100-km bodies is sufficient to bring liquid water to the near-surface and cause mineral alteration, or whether additional heat input at the surface (i.e, by impacts) is needed to provide a transient liquid water source for mineral hydration without large- scale liquid water transport.

Asteroids IV

NASA Astrophysics Data System (ADS)

Michel, Patrick; DeMeo, Francesca E.; Bottke, William F.

Asteroids are fascinating worlds. Considered the building blocks of our planets, many of the authors of this book have devoted their scientific careers to exploring them with the tools of our trade: ground- and spacebased observations, in situ space missions, and studies that run the gamut from theoretical modeling efforts to laboratory work. Like fossils for paleontologists, or DNA for geneticists, they allow us to construct a veritable time machine and provide us with tantalizing glimpses of the earliest nature of our solar system. By investigating them, we can probe what our home system was like before life or even the planets existed. The origin and evolution of life on our planet is also intertwined with asteroids in a different way. It is believed that impacts on the primordial Earth may have delivered the basic components for life, with biology favoring attributes that could more easily survive the aftermath of such energetic events. In this fashion, asteroids may have banished many probable avenues for life to relative obscurity. Similarly, they may have also prevented our biosphere from becoming more complex until more recent eras. The full tale of asteroid impacts on the history of our world, and how human life managed to emerge from myriad possibilities, has yet to be fully told. The hazard posed by asteroid impacts to our civilization is low but singular. The design of efficient mitigation strategies strongly relies on asteroid detection by our ground- and spacebased surveys as well as knowledge of their physical properties. A more positive motivation for asteroid discovery is that the proximity of some asteroids to Earth may allow future astronauts to harvest their water and rare mineral resources for use in exploration. A key goal of asteroid science is therefore to learn how humans and robotic probes can interact with asteroids (and extract their materials) in an efficient way. We expect that these adventures may be commonplace in the future. Asteroids, like planets, are driven by a great variety of both dynamical and physical mechanisms. In fact, images sent back by space missions show a collection of small worlds whose characteristics seem designed to overthrow our preconceived notions. Given their wide range of sizes and surface compositions, it is clear that many formed in very different places and at different times within the solar nebula. These characteristics make them an exciting challenge for researchers who crave complex problems. The return of samples from these bodies may ultimately be needed to provide us with solutions. In the book Asteroids IV, the editors and authors have taken major strides in the long journey toward a much deeper understanding of our fascinating planetary ancestors. This book reviews major advances in 43 chapters that have been written and reviewed by a team of more than 200 international authorities in asteroids. It is aimed to be as comprehensive as possible while also remaining accessible to students and researchers who are interested in learning about these small but nonetheless important worlds. We hope this volume will serve as a leading reference on the topic of asteroids for the decade to come. We are deeply indebted to the many authors and referees for their tremendous efforts in helping us create Asteroids IV. We also thank the members of the Asteroids IV scientific organizing committee for helping us shape the structure and content of the book. The conference associated with the book, "Asteroids Comets Meteors 2014" held June 30-July 4, 2014, in Helsinki, Finland, did an outstanding job of demonstrating how much progress we have made in the field over the last decade. We are extremely grateful to our host Karri Muinonnen and his team. The editors are also grateful to the Asteroids IV production staff, namely Renée Dotson and her colleagues at the Lunar and Planetary Institute, for their efforts, their invaluable assistance, and their enthusiasm; they made life as easy and pleasant as possible for the editors, authors, and referees. They also thank Richard Binzel, the General Editor of the Space Science Series, for his strong support and advice during this process, as well as the staff at the University of Arizona Press. Finally, editor Patrick Michel would like to thank his wife Delphine, who married him on June 14, 2013, almost at the birth of the book process. He is grateful that she was willing to put up with him as he spent many of his nights and weekends working on the book. Thanks to her support, their trajectories are as bounded as a perfectly stable asteroid binary system, and this was probably the best way to experience from the start what her life would be like with a researcher! Co-editor Bottke would also like to thank his wife Veronica and his children Kristina-Marie, Laura, and Julie, who make up his own favorite asteroid family. Since Asteroids III, the size distribution of the family members has been steadily changing, and who knows how many tiny new members it will contain by Asteroids V! Co-editor DeMeo would like to thank her husband Alfredo for his support and encouragement throughout the process of creating this book. They met at the beginning of her career in research, becoming an asteroid pair and now continuing on the same orbit in life.

New Research by CCD Scanning for Comets and Asteroids

NASA Technical Reports Server (NTRS)

Gehrels, Tom; McMillan, Robert S.

1997-01-01

The purpose of Spacewatch is to explore the various populations of small objects within the solar system. Spacewatch provides data for studies of comets and asteroids, finds potential targets for space missions, and provides information on the environmental problem of possible impacts. Moving objects are discovered by scanning the sky with charge-coupled devices (CCDs) on the 0.9-meter Spacewatch Telescope of the University of Arizona on Kitt Peak. Each Spacewatch scan consists of three drift scan passes over an area of sky using a CCD filtered to a bandpass of 0.5-1.0 microns (approximately V+R+I with peak sensitivity at 0.7 micron). The effective exposure time for each pass is 143 seconds multiplied by the secant of the declination. We have been finding some 30,000 new asteroids per year and applying their statistics to the study of the collisional history of the solar system. As of the end of the observing run of Nov. 1997, Spacewatch had found a total of 153 Near-Earth Asteroids (NEAs) and 8 new comets since the project began in the 1980s, and had recovered one lost comet. The total number of NEAs found by Spacewatch big enough to be hazardous if they were to impact the Earth is 36. Spacewatch is also efficient in recovery of known comets and has detected and reported positions for more than 137,000 asteroids, mostly new ones in the main belt, including more than 16,000 asteroids designated by the Minor Planet Center (MPC).

Small solar system bodies as granular systems

NASA Astrophysics Data System (ADS)

Hestroffer, Daniel; Campo Bagatín, Adriano; Losert, Wolfgang; Opsomer, Eric; Sánchez, Paul; Scheeres, Daniel J.; Staron, Lydie; Taberlet, Nicolas; Yano, Hajime; Eggl, Siegfried; Lecomte, Charles-Edouard; Murdoch, Naomi; Radjai, Fahrang; Richardson, Derek C.; Salazar, Marcos; Schwartz, Stephen R.; Tanga, Paolo

2017-06-01

Asteroids and other Small Solar System Bodies (SSSBs) are currently of great scientific and even industrial interest. Asteroids exist as the permanent record of the formation of the Solar System and therefore hold many clues to its understanding as a whole, as well as insights into the formation of planetary bodies. Additionally, SSSBs are being investigated in the context of impact risks for the Earth, space situational awareness and their possible industrial exploitation (asteroid mining). In all these aspects, the knowledge of the geophysical characteristics of SSSB surface and internal structure are of great importance. Given their size, constitution, and the evidence that many SSSBs are not simple monoliths, these bodies should be studied and modelled as self-gravitating granular systems in general, or as granular systems in micro-gravity environments in particular contexts. As such, the study of the geophysical characteristics of SSSBs is a multi-disciplinary effort that lies at the crossroads between Granular Mechanics, Celestial Mechanics, Soil Mechanics, Aerospace Engineering and Computer Sciences.

Asteroid Exploration with Autonomic Systems

NASA Technical Reports Server (NTRS)

Truszkowski, Walt; Rash, James; Rouff, Christopher; Hinchey, Mike

2004-01-01

NASA is studying advanced technologies for a future robotic exploration mission to the asteroid belt. The prospective ANTS (Autonomous Nano Technology Swarm) mission comprises autonomous agents including worker agents (small spacecra3) designed to cooperate in asteroid exploration under the overall authoriq of at least one ruler agent (a larger spacecraft) whose goal is to cause science data to be returned to Earth. The ANTS team (ruler plus workers and messenger agents), but not necessarily any individual on the team, will exhibit behaviors that qualify it as an autonomic system, where an autonomic system is defined as a system that self-reconfigures, self-optimizes, self-heals, and self-protects. Autonomic system concepts lead naturally to realistic, scalable architectures rich in capabilities and behaviors. In-depth consideration of a major mission like ANTS in terms of autonomic systems brings new insights into alternative definitions of autonomic behavior. This paper gives an overview of the ANTS mission and discusses the autonomic properties of the mission.

Is the U-B color sufficient for identifying water of hydration on solar system bodies?

NASA Technical Reports Server (NTRS)

Vilas, Faith

1995-01-01

The U-B color has been suggested as a predictor of the presence of water of hydration on asteroids. Photometry from the Eight-Color Asteroid Survey (ECAS) was used to test this concept. An overlap in U-B color prevents this magnitude difference from distinguishing between surface material that was thermally processed at higher temperatures and surface material that was aqueously altered. Two tests of the presence of water of hydration using visible spectral region photometry failed to flag those few higher albedo M- and E-class asteroids having photometry that shows a 3.0-micrometers water of hydration absorption. These asteroids probably contain little or no oxidized iron in their surface material.

Asteroid observations with NCSFCT AZT-8 telescope

NASA Astrophysics Data System (ADS)

Kozhukhov, O. M.; Maigurova, N. V.

2017-02-01

The asteroid observations of the small Solar System bodies were carried out with the AZT-8 telescope (D = 0.7 m, f/4) of the National Center of Space Facilities Control and Testing (NCSFCT) during 2010-2013. The telescope is located near Yevpatoria, the observatory code according IAU is B17. The observational program included perturbed main belt asteroids and NEO's for the GAIA FUN-SSO Company. The MPC database contains more than 4500 asteroids positions and magnitudes obtained during this period at AZT-8 telescope. The article presents analysis of the positional accuracy of B17 observations obtained from the comparison with the JPL HORIZONS ephemeris, and data from AstD-yS-2 and NEODyS-2 web services.

The violent collisional history of asteroid 4 Vesta.

PubMed

Marchi, S; McSween, H Y; O'Brien, D P; Schenk, P; De Sanctis, M C; Gaskell, R; Jaumann, R; Mottola, S; Preusker, F; Raymond, C A; Roatsch, T; Russell, C T

2012-05-11

Vesta is a large differentiated rocky body in the main asteroid belt that accreted within the first few million years after the formation of the earliest solar system solids. The Dawn spacecraft extensively imaged Vesta's surface, revealing a collision-dominated history. Results show that Vesta's cratering record has a strong north-south dichotomy. Vesta's northern heavily cratered terrains retain much of their earliest history. The southern hemisphere was reset, however, by two major collisions in more recent times. We estimate that the youngest of these impact structures, about 500 kilometers across, formed about 1 billion years ago, in agreement with estimates of Vesta asteroid family age based on dynamical and collisional constraints, supporting the notion that the Vesta asteroid family was formed during this event.

NASA's New Discovery Missions

NASA Image and Video Library

2017-01-04

On Jan. 4, 2017 NASA announced the selection of two missions to explore previously unexplored asteroids. The first mission, called Lucy, will study asteroids, known as Trojan asteroids, trapped by Jupiter’s gravity. The Psyche mission will explore a very large and rare object in the solar system’s asteroid belt that’s made of metal, and scientists believe might be the exposed core of a planet that lost its rocky outer layers from a series of violent collisions. Lucy is targeted for launch in 2021 and Psyche in 2023. Both missions have the potential to open new windows on one of the earliest eras in the history of our solar system – a time less than 10 million years after the birth of our sun.

Recovery and normalization of triple coincidences in PET.

PubMed

Lage, Eduardo; Parot, Vicente; Moore, Stephen C; Sitek, Arkadiusz; Udías, Jose M; Dave, Shivang R; Park, Mi-Ae; Vaquero, Juan J; Herraiz, Joaquin L

2015-03-01

Triple coincidences in positron emission tomography (PET) are events in which three γ-rays are detected simultaneously. These events, though potentially useful for enhancing the sensitivity of PET scanners, are discarded or processed without special consideration in current systems, because there is not a clear criterion for assigning them to a unique line-of-response (LOR). Methods proposed for recovering such events usually rely on the use of highly specialized detection systems, hampering general adoption, and/or are based on Compton-scatter kinematics and, consequently, are limited in accuracy by the energy resolution of standard PET detectors. In this work, the authors propose a simple and general solution for recovering triple coincidences, which does not require specialized detectors or additional energy resolution requirements. To recover triple coincidences, the authors' method distributes such events among their possible LORs using the relative proportions of double coincidences in these LORs. The authors show analytically that this assignment scheme represents the maximum-likelihood solution for the triple-coincidence distribution problem. The PET component of a preclinical PET/CT scanner was adapted to enable the acquisition and processing of triple coincidences. Since the efficiencies for detecting double and triple events were found to be different throughout the scanner field-of-view, a normalization procedure specific for triple coincidences was also developed. The effect of including triple coincidences using their method was compared against the cases of equally weighting the triples among their possible LORs and discarding all the triple events. The authors used as figures of merit for this comparison sensitivity, noise-equivalent count (NEC) rates and image quality calculated as described in the NEMA NU-4 protocol for the assessment of preclinical PET scanners. The addition of triple-coincidence events with the authors' method increased peak NEC rates of the scanner by 26.6% and 32% for mouse- and rat-sized objects, respectively. This increase in NEC-rate performance was also reflected in the image-quality metrics. Images reconstructed using double and triple coincidences recovered using their method had better signal-to-noise ratio than those obtained using only double coincidences, while preserving spatial resolution and contrast. Distribution of triple coincidences using an equal-weighting scheme increased apparent system sensitivity but degraded image quality. The performance boost provided by the inclusion of triple coincidences using their method allowed to reduce the acquisition time of standard imaging procedures by up to ∼25%. Recovering triple coincidences with the proposed method can effectively increase the sensitivity of current clinical and preclinical PET systems without compromising other parameters like spatial resolution or contrast.

ASTEX - a study of a lander and orbiter mission to two near-Earth asteroids

NASA Astrophysics Data System (ADS)

Boehnhardt, Hermann; Nathues, Andreas; Harris, Alan; Astex Study Team

ASTEX stands for a feasibility study of an exploration mission to two near-Earth asteroids. The targets should have different mineralogical constitution, more specifically one asteroid should be of ‘primitive" nature, the other one should be "evolved". The scientific goal of such a mission is to explore the physical, geological and compositional constitution of the asteroids as planetary bodies as well as to provide information and constraints on the formation and evolution history of the objects per se and of the planetary system, here the asteroid belt, as a whole. Two aspects play an important role, i.e. the search and exploration for the origin and evolution of the primordial material for the formation of life in the solar system on one side and the understanding of the processes that have led to mineralogical differentiation of planetary embryos on the other side. The mission scenario consists of an orbiting and landing phase at each target. The immediate aims of the study are (1) to identify potential targets and to develop for selected pairs more detailed mission scenarios including the best possible propulsion systems to be used, (2) to define the scientific payload of the mission, (3) to analyse the requirements and options for the spacecraft bus and the lander system, and (4) to assess and to define requirements for the operational ground segment of the mission.This eight-months study is directed by the MPI for Solar System Research under support grant by DLR Bonn-Oberkassel and is performed in close collaboration between German scientific research institutes and industry. It is considered complementary to mission studies performed elsewhere and focussing on sample return and impact hazards and their remedy from near-Earth objects.

Laboratory Simulations of Space Weathering of Asteroid Surfaces by Solar Wind Ions.

NASA Astrophysics Data System (ADS)

Miller, Kenneth A.; De Ruette, Nathalie; Harlow, George; Domingue, Deborah L.; Savin, Daniel Wolf

2014-06-01

Studies into the formation of the terrestrial planets rely on the analysis of asteroids and meteorites. Asteroids are solar system remnants from the planetary formation period. By characterizing their mineralogical composition we can better constrain the formation and evolution of the inner planets.Remote sensing is the primary means for studying asteroids. Sample return missions, such as Hayabusa, are complex and expensive, hence we rely on asteroid reflectance spectra to determine chemical composition. Links have been made and debated between meteorite classes and asteroid types [1, 2]. If such relationships can be confirmed, then meteorites would provide a low cost asteroid sample set for study. However, a major issue in establishing this link is the spectral differences between meteorite samples and asteroid surfaces. The most commonly invoked explanation for these differences is that the surfaces of asteroids are space weathered [2, 3]. The dominant mechanism for this weathering is believed to be solar-wind ion irradiation [2, 4, 5]. Laboratory simulations of space weathering have demonstrated changes in the general direction required to alter spectra from unweathered meteorite samples to asteroid observations [3, 6 -10], but many open questions remain and we still lack a comprehensive understanding. We propose to explore the alleged connection of ordinary chondrite (OC) meteorites to S-type asteroids through a series of systematic laboratory simulations of solar-wind space weathering of asteroid surface materials. Here we describe the issue in more detail and describe the proposed apparatus. [1] Chapman C. R. (1996) Meteorit. Planet. Sci., 31, 699-725. [2] Chapman C. R. (2004), Annu. Rev. Earth Planet. Sci., 32, 539-567. [3] Hapke B. (2001) J. Ge-ophys. Res., 106, 10039-10074. [4] Pieters C.M. et al. (2000) Meteorit. Planet. Sci., 35, 1101-1107. [5] Ver-nazza P. et al. (2009) Nature, 458, 993-995. [6] Stra-zulla G. et al. (2005) Icarus, 174, 31-35 (2005). [7] Brunetto R and Strazzulla G (2005) Icarus, 179, 265-273. [8] Marchi S et al. (2005) Astron. Astrophys., 443, 769-775. [9] Loeffler M. J. et al. (2009) J. Geo-phys. Res., 114, E03003. [10] Fu X. et al. (2012) Ica-rus, 219, 630-640

A new mechanism for the formation of regolith on asteroids

NASA Astrophysics Data System (ADS)

Delbo, Marco; Libourel, Guy; Wilkerson, Justin; Murdoch, Naomi; Michel, Patrick; Ramesh, Kt; Ganino, Clement; Verati, Chrystele; Marchi, Simone

2014-11-01

The soil of asteroids, like that of the Moon, and other rocky, airless bodies in the Solar System, is made of a layer of pebbles, sand, and dust called regolith.Previous works suggested that the regolith on asteroids is made from material ejected from impacts and re-accumulated on the surface and from surface rocks that are broken down by micrometeoroid impacts. However, this regolith formation process has problems to explain the regolith on km-sized and smaller asteroids: it is known that impact fragments can reach escape velocities and breaks free from the gravitational forces of these small asteroids, indicating the impact mechanism is not the dominant process for regolith creation. Other studies also reveal that there is too much regolith on small asteroids’ surfaces to have been deposited there solely by impacts over the millions of years of asteroids’ evolution.We proposed that another process is capable of gently breaking rocks at the surface of asteroids: thermal fatigue by temperature cycling. As asteroids spin about their rotation axes, their surfaces go in and out of shadow resulting in large surface temperature variations. The rapid heating and cooling creates thermal expansion and contraction in the asteroid material, initiating cracking and propagating existing cracks. As the process is repeated over and over, the crack damage increases with time, leading eventually to rock fragmentation (and production of new regolith).To study this process, in the laboratory, we subjected meteorites, used as asteroid material analogs, to 37 days of thermal cycles similar to those occurring on asteroids. We measured cracks widening at an average rate of 0.5 mm/y. Some fragments were also produced, indicating meteorite fragmentation. To scale our results to asteroid lifetime, we incorporated our measurements into a fracture model and we deduced that thermal cycling is more efficient than micrometeorite bombardment at fragmenting rock over millions of years on asteroids (see Delbo et al. 2014. Nature 508, 233-236).This work was supported by the French Agence National de la Recherche (ANR) SHOCKS,

Laser speckle strain and deformation sensor using linear array image cross-correlation method for specifically arranged triple-beam triple-camera configuration

NASA Technical Reports Server (NTRS)

Sarrafzadeh-Khoee, Adel K. (Inventor)

2000-01-01

The invention provides a method of triple-beam and triple-sensor in a laser speckle strain/deformation measurement system. The triple-beam/triple-camera configuration combined with sequential timing of laser beam shutters is capable of providing indications of surface strain and structure deformations. The strain and deformation quantities, the four variables of surface strain, in-plane displacement, out-of-plane displacement and tilt, are determined in closed form solutions.

Asteroid Origins Satellite (AOSAT) I: An On-orbit Centrifuge Science Laboratory

NASA Astrophysics Data System (ADS)

Lightholder, Jack; Thoesen, Andrew; Adamson, Eric; Jakubowski, Jeremy; Nallapu, Ravi; Smallwood, Sarah; Raura, Laksh; Klesh, Andrew; Asphaug, Erik; Thangavelautham, Jekan

2017-04-01

Exploration of asteroids, comets and small moons (small bodies) can answer fundamental questions relating to the formation of the solar system, the availability of resources, and the nature of impact hazards. Near-earth asteroids and the small moons of Mars are potential targets of human exploration. But as illustrated by recent missions, small body surface exploration remains challenging, expensive, and fraught with risk. Despite their small size, they are among the most extreme planetary environments, with low and irregular gravity, loosely bound regolith, extreme temperature variation, and the presence of electrically charged dust. Here we describe the Asteroid Origins Satellite (AOSAT-I), an on-orbit, 3U CubeSat centrifuge using a sandwich-sized bed of crushed meteorite fragments to replicate asteroid surface conditions. Demonstration of this CubeSat will provide a low-cost pathway to physical asteroid model validation, shed light on the origin and geophysics of asteroids, and constrain the design of future landers, rovers, resource extractors, and human missions. AOSAT-I will conduct scientific experiments within its payload chamber while operating in two distinct modes: (1) as a nonrotating microgravity laboratory to investigate primary accretion, and (2) as a rotating centrifuge producing artificial milligravity to simulate surface conditions on asteroids, comets and small moons. AOSAT-I takes advantage of low-cost, off-the-shelf components, modular design, and the rapid assembly and instrumentation of the CubeSat standard, to answer fundamental questions in planetary science and reduce cost and risk of future exploration.

Radar Discovery and Characterization of Binary Near-Earth Asteroids

NASA Technical Reports Server (NTRS)

Margot, J. L.; Nolan, M. C.; Benner, L. A. M.; Ostro, S. J.; Jurgens, R. F.; Giorgini, J. D.; Slade, M. A.; Howell, E. S.; Campbell, D. B.

2002-01-01

The radar instruments at Arecibo and Goldstone recently provided the first confirmed discoveries of binary asteroids in the near-Earth population. The physical and orbital properties of four near-Earth binary systems are described in detail. Additional information is contained in the original extended abstract.

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

Steinberg, Elad; Sari, Re’em

The Asteroid Belt and the Kuiper Belt are relics from the formation of our solar system. Understanding the size and spin distribution of the two belts is crucial for a deeper understanding of the formation of our solar system and the dynamical processes that govern it. In this paper, we investigate the effect of collisions on the evolution of the spin distribution of asteroids and KBOs. We find that the power law nature of the impactors’ size distribution leads to a Lévy distribution of the spin rates. This results in a power law tail in the spin distribution, in starkmore » contrast to the usually quoted Maxwellian distribution. We show that for bodies larger than 10 km, collisions alone lead to spin rates peaking at 0.15–0.5 revolutions per day. Comparing that to the observed spin rates of large asteroids (R > 50 km), we find that the spins of large asteroids, peaking at ∼1–2 revolutions per day, are dominated by a primordial component that reflects the formation mechanism of the asteroids. Similarly, the Kuiper Belt has undergone virtually no collisional spin evolution, assuming current densities. Collisions contribute a spin rate of ∼0.01 revolutions per day, thus the observed fast spin rates of KBOs are also primordial in nature.« less

Solar System Research with the Spacewatch 1.8-m Telescope

NASA Technical Reports Server (NTRS)

McMillan, Robert S.

2001-01-01

During this grant period, the 1.8-m Spacewatch telescope was put into routine operation to search for asteroids and comets ranging in location from near-Earth space to regions beyond the orbit of Neptune. All of these classes of objects can be detected simultaneously with our uniform scanning procedures. We are studying near Earth objects (NEOs), main belt asteroids, comets, Centaurs, and trans-Neptunian objects (TNOs), as well as the interrelationships of these classes and their bearing on the origin and evolution of the solar system. The Spacewatch 1.8-meter telescope is sensitive to V(mag) < 22.6 in sidereal scanning mode and is able to reach even fainter in longer 'staring' exposures, with a field of view 0.5 degrees square. These faint limits make the operation of the Spacewatch 1.8-m telescope complementary to asteroid surveys being done by other groups. Specifically, EAs smaller than 100 m in diameter and small main belt asteroids can be found, as well as more distant objects such as Centaurs/Scattered Disk Objects (SDOs) and TNOs. The 1.8-m telescope is also being used to do recoveries and astrometry of recently-discovered asteroids that subsequently become too faint for the other groups before good orbits are established.

Angular Asteroid Composite

NASA Image and Video Library

2017-02-10

This composite of 25 images of asteroid 2017 BQ6 was generated with radar data collected using NASA's Goldstone Solar System Radar in California's Mojave Desert. The images were gathered on Feb. 7, 2017, between 8:39 and 9:50 p.m. PST (11:39 p.m. EST and 12:50 a.m., Feb. 7), revealing an irregular, angular-appearing asteroid about 660 feet (200 meters) in size that rotates about once every three hours. The images have resolutions as fine as 12 feet (3.75 meters) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA21452

Virtual Observatory and Colitec Software: Modules, Features, Methods

NASA Astrophysics Data System (ADS)

Pohorelov, A. V.; Khlamov, S. V.; Savanevych, V. E.; Briukhovetskyi, A. B.; Vlasenko, V. P.

In this article we described complex processing system created by the CoLiTec project. This system includes features, user-friendly tools for processing control, results reviewing, integration with online catalogs and a lot of different computational modules that are based on the developed methods. Some of them are described in the article.The main directions of the CoLiTec software development are the Virtual Observatory, software for automated asteroids and comets detection and software for brightness equalization.The CoLiTec software is widely used in a number of observatories in the CIS. It has been used in about 700 000 observations, during which 1560 asteroids, including 5 NEO, 21 Trojan asteroids of Jupiter, 1 Centaur and four comets were discovered.

NEOCAM: Near Earth Object Chemical Analysis Mission: Bridging the Gulf between Telescopic Observations and the Chemical and Mineralogical Compositions of Asteroids or Diogenes A: Diagnostic Observation of the Geology of Near Earth Spectrally-Classified Asteroids

NASA Technical Reports Server (NTRS)

Nuth, Joseph A.

2009-01-01

Studies of meteorites have yielded a wealth of scientific information based on highly detailed chemical and isotopic studies possible only in sophisticated terrestrial laboratories. Telescopic studies have revealed an enormous (greater than 10(exp 5)) number of physical objects ranging in size from a few tens of meters to several hundred kilometers, orbiting not only in the traditional asteroid belt between Mars and Jupiter but also throughout the inner solar system. Many of the largest asteroids are classed into taxonomic groups based on their observed spectral properties and are designated as C, D. X, S or V types (as well as a wide range in sub-types). These objects are certainly the sources far the meteorites in our laboratories, but which asteroids are the sources for which meteorites? Spectral classes are nominally correlated to the chemical composition and physical characteristics of the asteroid itself based on studies of the spectral changes induced in meteorites due to exposure to a simulated space environment. While laboratory studies have produced some notable successes (e.g. the identification of the asteroid Vesta as the source of the H, E and D meteorite classes), it is unlikely that we have samples of each asteroidal spectral type in our meteorite collection. The correlation of spectral type and composition for many objects will therefore remain uncertain until we can return samples of specific asteroid types to Earth for analyses. The best candidates for sample return are asteroids that already come close to the Earth. Asteroids in orbit near 1 A.U. have been classified into three groups (Aten, Apollo & Amor) based on their orbital characteristics. These Near Earth Objects (NEOs) contain representatives of virtually all spectral types and sub-types of the asteroid population identified to date. Because of their close proximity to Earth, NEOs are prime targets for asteroid missions such as the NEAR-Shoemaker NASA Discovery Mission to Eros and the Japanese Hyabusa Mission to Itokawa. Also due to their close proximity to Earth, NEOs constitute the most likely set of celestial objects that will impact us in the relatively near future.

Determination of the Period of Binary Asteroid Systems

NASA Astrophysics Data System (ADS)

Lust, Nathaniel B.; Britt, D. T.

2008-09-01

In the study of asteroids, binary pairs offer a unique window of study. By observing these systems and determining the period of the secondary, it is possible to determine system mass (e.g. Pravec and Hahn 1997; Ryan et al., 2004). With mass and volume, properties such as bulk density and porosity can be derived. At the University of Central Florida we have begun a binary asteroid hunt, in conjunction with the Prague consortium, in order to identify new binary candidates and to better constrain data on known pairs. All of the observations are collected on campus using a 0.5meter f/8.1 Ritchey-Chretien telescope with a SBIG STL-6303E detector. For our first test target we observed the known binary asteroid 107 Camila over a period of six days for approximately six to eight hours a night. The data is then processed using an open source python algorithm developed by Nate Lust. The data is read in, reduced, and compared to a standard star. Once the light curve was generated we make use of the CLEAN algorithm, originally developed by Hogbom (1974), to extract meaningful periods from the light curve.

Chondritic Asteroids--When Did Aqueous Alteration Happen?

NASA Astrophysics Data System (ADS)

Doyle, P. M.

2015-06-01

Using a synthesized fayalite (Fe2SiO4) standard for improved 53Mn-53Cr radiometric age dating, Patricia Doyle (previously at the University of Hawaii and now at the University of Cape Town, South Africa) and coauthors from Hawaii, the National Astronomical Observatory of Japan, University of Chicago, and Lawrence Livermore National Laboratory in California, analyzed aqueously formed fayalite in the ordinary chondrite Elephant Moraine 90161 (L3.05) and in the carbonaceous chondrites Asuka 881317 (CV3) and MacAlpine Hills 88107 (CO3-like) from Antarctica. The data obtained indicate that liquid water existed - and aqueous alteration started - on the chondritic parent bodies about three million years earlier than previously determined. This discovery has implications for understanding when and where the asteroids accreted. The 53Mn-53Cr chronology of chondrite aqueous alteration, combined with thermodynamic calculations and physical modeling, signifies that hydrated asteroids, at least those sampled by meteorites, accreted in the inner Solar System (2-4 AU) near the main asteroid belt 2-4 million years after the beginning of the Solar System, rather than migrating inward after forming in the Solar System's colder, outer regions beyond Jupiter's present orbit (5-15 AU).

Forming the wide asynchronous binary asteroid population

NASA Astrophysics Data System (ADS)

Jacobson, S.; Scheeres, D.; McMahon, J.

2014-07-01

We propose and analyze a new mechanism for the formation of the wide asynchronous binary population. These binary asteroids have wide semi-major axes relative to most near-Earth-asteroid and main-belt-asteroid systems as shown in the attached table. Confirmed members have rapidly rotating primaries and satellites that are not tidally locked. Previously suggested formation mechanisms from impact ejecta, from planetary flybys, and directly from rotational-fission events cannot satisfy all of the observations. The newly hypothesized mechanism works as follows: (1) these systems are formed from rotational fission, (2) their satellites are tidally locked, (3) their orbits are expanded by the binary Yarkovsky-O'Keefe-Radzievskii-Paddack (BYORP) effect, (4) their satellites desynchronize as a result of the adiabatic invariance between the libration of the secondary and the mutual orbit, and (5) the secondary avoids resynchronization because of the YORP effect. This seemingly complex chain of events is a natural pathway for binaries with satellites that have particular shapes, which define the BYORP effect torque that acts on the system. After detailing the theory, we analyze each of the wide-asynchronous-binary members and candidates to assess their most likely formation mechanism. Finally, we suggest possible future observations to check and constrain our hypothesis.

Fundamental Constraints on the Coherence of Probing Signals in the Problem of Maximizing the Resolution and Range in the Stroboscopic Range of Asteroids

NASA Astrophysics Data System (ADS)

Zakharchenko, V. D.; Kovalenko, I. G.; Pak, O. V.; Ryzhkov, V. Yu.

2018-05-01

The problem of coherence violation in stroboscopic ranging with a high resolution in the range due to mutual phase instability of probing and reference radio signals has been considered. It has been shown that the violation of coherence in stroboscopic ranging systems is equivalent to the action of modulating interface and leads to a decrease in the system sensitivity. Requirements have been formulated for the coherence of reference generators in the stroboscopic processing system. The results of statistical modeling have been presented. It was shown that, in the current state of technology with stability of the frequencies of the reference generators, the achieved coherence is sufficient to probe asteroids with super-resolving signals in the range of up to 70 million kilometers. In this case, the dispersion of the signal in cosmic plasma limits the value of the linear resolution of the asteroid details at this range by the value of 2.7 m. Comparison with the current radar resolution of asteroids has been considered, which, at the end of 2015, were 7.5 m in the range of 7 million kilometers.

An infrared search in our solar system as part of a more flexible search strategy

NASA Astrophysics Data System (ADS)

Papagiannis, M. D.

One of several explanations for the Fermi Paradox is that the whole Galaxy, including the solar system, has already been colonized, but that for a variety of reasons the extraterrestrials have chosen not to reveal their presence. IRAS has obtained a large volume of infrared data at 12, 25, 60, and 100 microns from which a special working group at JPL, is trying to establish a special catalog of solar system objects, the vast majority of which are asteroids. A careful search through this data bank for objects with peculiar infrared spectra would be the first step in the search for major artificial objects, such as space stations or materials processing plants, in the solar system. The asteroid belt is an ideal source of raw materials for space colonies, which could have easily escaped detection lost among the many thousands of natural asteroids. Checking them out for excesses in the infrared is an ideal screening test for artificial objects in the solar system.

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.

Spectral decomposition of asteroid Itokawa based on principal component analysis

NASA Astrophysics Data System (ADS)

Koga, Sumire C.; Sugita, Seiji; Kamata, Shunichi; Ishiguro, Masateru; Hiroi, Takahiro; Tatsumi, Eri; Sasaki, Sho

2018-01-01

The heliocentric stratification of asteroid spectral types may hold important information on the early evolution of the Solar System. Asteroid spectral taxonomy is based largely on principal component analysis. However, how the surface properties of asteroids, such as the composition and age, are projected in the principal-component (PC) space is not understood well. We decompose multi-band disk-resolved visible spectra of the Itokawa surface with principal component analysis (PCA) in comparison with main-belt asteroids. The obtained distribution of Itokawa spectra projected in the PC space of main-belt asteroids follows a linear trend linking the Q-type and S-type regions and is consistent with the results of space-weathering experiments on ordinary chondrites and olivine, suggesting that this trend may be a space-weathering-induced spectral evolution track for S-type asteroids. Comparison with space-weathering experiments also yield a short average surface age (< a few million years) for Itokawa, consistent with the cosmic-ray-exposure time of returned samples from Itokawa. The Itokawa PC score distribution exhibits asymmetry along the evolution track, strongly suggesting that space weathering has begun saturated on this young asteroid. The freshest spectrum found on Itokawa exhibits a clear sign for space weathering, indicating again that space weathering occurs very rapidly on this body. We also conducted PCA on Itokawa spectra alone and compared the results with space-weathering experiments. The obtained results indicate that the first principal component of Itokawa surface spectra is consistent with spectral change due to space weathering and that the spatial variation in the degree of space weathering is very large (a factor of three in surface age), which would strongly suggest the presence of strong regional/local resurfacing process(es) on this small asteroid.

Arecibo Radar Observations of Near-Earth Asteroids: A Study in Heterogeneity

NASA Technical Reports Server (NTRS)

Nolan, M. C.; Howell, E. S.; Margot J.-L.; Ostro, S. J; Benner, L. A. M.; Giorgini, J. D.; Campbell, D. B.

2002-01-01

Characterization of the rotation state and structure of near-Earth asteroids through radar observations using the Arecibo and Goldstone planetary radar systems shows the remarkable variety of these objects, and suggests variety of formation and modification mechanisms. Additional information is contained in the original extended abstract.

Serendipitous observations of asteroids in Herschel PACS and SPIRE maps

NASA Astrophysics Data System (ADS)

Szakáts, R.; Kiss, Cs.; Marton, G.; Varga-Verebélyi, E.; Müller, T.; Pál, A.

2017-09-01

We present our methods and results in finding serendipitous solar system objects on Herschel PACS and SPIRE maps. We can use this data to supplement the Herschel PACS and SPIRE point source catalogs with flags of possible contamination and to obtain thermal infrared fluxes for these asteroids.

ATLAS: A High-cadence All-sky Survey System

NASA Astrophysics Data System (ADS)

Tonry, J. L.; Denneau, L.; Heinze, A. N.; Stalder, B.; Smith, K. W.; Smartt, S. J.; Stubbs, C. W.; Weiland, H. J.; Rest, A.

2018-06-01

Technology has advanced to the point that it is possible to image the entire sky every night and process the data in real time. The sky is hardly static: many interesting phenomena occur, including variable stationary objects such as stars or QSOs, transient stationary objects such as supernovae or M dwarf flares, and moving objects such as asteroids and the stars themselves. Funded by NASA, we have designed and built a sky survey system for the purpose of finding dangerous near-Earth asteroids (NEAs). This system, the “Asteroid Terrestrial-impact Last Alert System” (ATLAS), has been optimized to produce the best survey capability per unit cost, and therefore is an efficient and competitive system for finding potentially hazardous asteroids (PHAs) but also for tracking variables and finding transients. While carrying out its NASA mission, ATLAS now discovers more bright (m < 19) supernovae candidates than any ground based survey, frequently detecting very young explosions due to its 2 day cadence. ATLAS discovered the afterglow of a gamma-ray burst independent of the high energy trigger and has released a variable star catalog of 5 × 106 sources. This is the first of a series of articles describing ATLAS, devoted to the design and performance of the ATLAS system. Subsequent articles will describe in more detail the software, the survey strategy, ATLAS-derived NEA population statistics, transient detections, and the first data release of variable stars and transient light curves.

Design concepts and options for the Thermal Infrared Imager (TIRI) as part of ESA's Asteroid Impact Mission.

NASA Astrophysics Data System (ADS)

Bowles, Neil; Calcutt, Simon; Licandro, Javier; Reyes, Marcos; Delbo, Marco; Donaldson Hanna, Kerri; Arnold, Jessica; Howe, Chris

2016-04-01

ESA's Asteroid Impact Mission (AIM) is being studied as part of the joint ESA/NASA AIDA mission for launch in 2020. AIDA's primary mission is to investigate the effect of a kinetic impactor on the secondary component of the binary asteroid 65803 Didymos in late 2022. AIM will characterise the Didymos system and monitor the response of the binary system to the impact. A multi-spectral, thermal-infrared imaging instrument (TIRI) will be an essential component of AIM's remote sensing payload, as it will provide key information on the nature of the surfaces (e.g. presence or absence of materials, degree of compaction, and rock abundance of the regolith) of both components in the Didymos system. The temperature maps provided by TIRI will be important for navigation and spacecraft health and safety for proximity/lander operations. By measuring the asteroids' diurnal thermal responses (thermal inertia) and their surface compositions via spectral signatures, TIRI will provide information on the origin and evolution of the binary system. In this presentation we will discuss possible instrument design for TIRI, exploring options that include imaging spectroscopy to broadband imaging. By using thermal models and compositional analogues of the Didymos system we will show how the performance of each design option compares to the wider scientific goals of the AIDA/AIM mission.

Technologies Enabling Scientific Exploration of Asteroids and Moons

NASA Astrophysics Data System (ADS)

Shaw, A.; Fulford, P.; Chappell, L.

2016-12-01

Scientific exploration of moons and asteroids is enabled by several key technologies that yield topographic information, allow excavation of subsurface materials, and allow delivery of higher-mass scientific payloads to moons and asteroids. These key technologies include lidar systems, robotics, and solar-electric propulsion spacecraft buses. Many of these technologies have applications for a variety of planetary targets. Lidar systems yield high-resolution shape models of asteroids and moons. These shape models can then be combined with radio science information to yield insight into density and internal structure. Further, lidar systems allow investigation of topographic surface features, large and small, which yields information on regolith properties. Robotic arms can be used for a variety of purposes, especially to support excavation, revealing subsurface material and acquiring material from depth for either in situ analysis or sample return. Robotic arms with built-in force sensors can also be used to gauge the strength of materials as a function of depth, yielding insight into regolith physical properties. Mobility systems allow scientific exploration of multiple sites, and also yield insight into regolith physical properties due to the interaction of wheels with regolith. High-power solar electric propulsion (SEP) spacecraft bus systems allow more science instruments to be included on missions given their ability to support greater payload mass. In addition, leveraging a cost-effective commercially-built SEP spacecraft bus can significantly reduce mission cost.

A Policy Framework for Health Systems to Promote Triple Aim Innovation.

PubMed

Verma, Amol; Bhatia, Sacha

2016-01-01

With the expiry of the Health Accords, provincial governments must face the challenge of improving performance in the context of ageing demographics, increasing multi-morbidity, and real concerns about financial stability. The Institute for Healthcare Improvement Triple Aim articulates fundamental goals that can guide health system transformation: improved population health, enhanced patient experience and reduced or stable per capita costs. Advancing fragmented and costly health systems in pursuit of these goals requires transformative, as opposed to iterative, change. Provincial governments are ideally suited to lead this change by acting as "integrators" who link healthcare organizations and align incentives across the spectrum of delivery. Although there is very limited evidence regarding the effectiveness of system-level reforms, we draw on initiatives from around the world to suggest policies that can promote system-level Triple Aim innovation. We categorize these policies within the classic functions ascribed to health systems: financing, stewardship and resource generation. As healthcare financers, governments should orient procurement policy towards the Triple Aim innovation and reform payment to reward value not volume. As health system stewards, governments should define a Triple Aim vision; measure and report outcomes, patient experience, and costs; integrate across sectors; and facilitate learning from failure and spread of successful innovation. As resource generators, governments should invest in health information technology to exploit "big data" and ensure that professional education equips front-line clinicians with skills necessary to improve systems. There are a number of barriers to system-level Triple Aim innovation. There is a lack of evidence for macro-level policy changes, innovation is costly and complicated, and system reform may not be politically appealing. Triple Aim innovation may also be conflated with organization-level quality improvement initiatives. These barriers can be overcome with effective leadership. A mandate and funding to evaluate reforms can be built into laws. Innovation can be funded by shared savings and health gains. Reform may be more politically viable in the current climate of austerity. The Triple Aim framework offers aspirational and concrete objectives that should be integrated into the health system design by Canadian provincial governments to improve health system performance.

Encircling the dark, a simple method to decipher the cosmos

NASA Astrophysics Data System (ADS)

Quirico, Eric

2017-09-01

Asteroids are relics of Solar System formation and host insightful information on physical, chemical, chronological and dynamical conditions that operated, since the formation of the first solids until the Late Heavy Bombardment. Since 2000, our view on these small objects has been deeply transformed due to several space missions and advances in ground-based observations. Near, Dawn (NASA) and Hayabusa 1 (JAXA) have provided extensive characterizations of the surface and interior of asteroids 433Eros, Itokawa, Vesta and Ceres, and revealed a complex morphology driven by collisions and/or internal activity. The samples returned to Earth by Hayabusa 1 provided a firm evidence of the genetic link between S-type asteroids and ordinary chondrites, and valuable clues on the first stage of space weathering. Meanwhile, ground-based observations, dynamical theory and meteoritics have drawn a big picture pointing to a continuum between asteroids and comets. Hopefully, the forthcoming missions Hayabusa2 and Osiris ReX will explore for the first time two C-type asteroids in the next years.

Origin of asteroids and the missing planet

NASA Technical Reports Server (NTRS)

Opik, E. J.

1977-01-01

Consideration is given to Ovenden's (1972) theory concerning the existence of a planet of 90 earth masses which existed from the beginning of the solar system and then disappeared 16 million years ago, leaving only asteroids. His model for secular perturbations is reviewed along with the principle of least interaction action (1972, 1973, 1975) on which the model is based. It is suggested that the structure of the asteroid belt and the origin of meteorites are associated with the vanished planet. A figure of 0.001 earth masses is proposed as a close estimate of the mass of the asteroidal belt. The hypothesis that the planet was removed through an explosion is discussed, noting the possible origin of asteroids in such a manner. Various effects of the explosion are postulated, including the direct impact of fragments on the earth, their impact on the sun and its decreased radiation, and the direct radiation of the explosion. A model for the disappearance of the planet by ejection in a gravitational encounter with a passing mass is also described.

Moving Object Detection Using a Parallax Shift Vector Algorithm

NASA Astrophysics Data System (ADS)

Gural, Peter S.; Otto, Paul R.; Tedesco, Edward F.

2018-07-01

There are various algorithms currently in use to detect asteroids from ground-based observatories, but they are generally restricted to linear or mildly curved movement of the target object across the field of view. Space-based sensors in high inclination, low Earth orbits can induce significant parallax in a collected sequence of images, especially for objects at the typical distances of asteroids in the inner solar system. This results in a highly nonlinear motion pattern of the asteroid across the sensor, which requires a more sophisticated search pattern for detection processing. Both the classical pattern matching used in ground-based asteroid search and the more sensitive matched filtering and synthetic tracking techniques, can be adapted to account for highly complex parallax motion. A new shift vector generation methodology is discussed along with its impacts on commonly used detection algorithms, processing load, and responsiveness to asteroid track reporting. The matched filter, template generator, and pattern matcher source code for the software described herein are available via GitHub.

How long will asteroids on retrograde orbits survive?

NASA Astrophysics Data System (ADS)

Kankiewicz, Paweł; Włodarczyk, Ireneusz

2018-05-01

Generally, a common scenario for the origin of minor planets with high orbital inclinations does not exist. This applies especially to objects whose orbital inclinations are much greater than 90° (retrograde asteroids). Since the discovery of Dioretsa in 1999, approximately 100 small bodies now are classified as retrograde asteroids. A small number of them were reclassified as comets, due to cometary activity. There are only 25 multi-opposition retrograde asteroids, with a relatively large number of observations and well-determined orbits. We studied the orbital evolution of numbered and multi-opposition retrograde asteroids by numerical integration up to 1 Gy forward and backward in time. Additionally, we analyzed the propagation of orbital elements with the observational errors, determined dynamical lifetimes and studied their chaotic properties. Conclusively, we obtained quantitative parameters describing the long-term stability of orbits relating to the past and the future. In turn, we were able to estimate their lifetimes and how long these objects will survive in the Solar System.

The Ginger-shaped Asteroid 4179 Toutatis: New Observations from a Successful Flyby of Chang'e-2

NASA Astrophysics Data System (ADS)

Huang, Jiangchuan; Ji, Jianghui; Ye, Peijian; Wang, Xiaolei; Yan, Jun; Meng, Linzhi; Wang, Su; Li, Chunlai; Li, Yuan; Qiao, Dong; Zhao, Wei; Zhao, Yuhui; Zhang, Tingxin; Liu, Peng; Jiang, Yun; Rao, Wei; Li, Sheng; Huang, Changning; Ip, Wing-Huen; Hu, Shoucun; Zhu, Menghua; Yu, Liangliang; Zou, Yongliao; Tang, Xianglong; Li, Jianyang; Zhao, Haibin; Huang, Hao; Jiang, Xiaojun; Bai, Jinming

2013-12-01

On 13 December 2012, Chang'e-2 conducted a successful flyby of the near-Earth asteroid 4179 Toutatis at a closest distance of 770 +/- 120 meters from the asteroid's surface. The highest-resolution image, with a resolution of better than 3 meters, reveals new discoveries on the asteroid, e.g., a giant basin at the big end, a sharply perpendicular silhouette near the neck region, and direct evidence of boulders and regolith, which suggests that Toutatis may bear a rubble-pile structure. Toutatis' maximum physical length and width are (4.75 × 1.95 km) +/-10%, respectively, and the direction of the +z axis is estimated to be (250 +/- 5°, 63 +/- 5°) with respect to the J2000 ecliptic coordinate system. The bifurcated configuration is indicative of a contact binary origin for Toutatis, which is composed of two lobes (head and body). Chang'e-2 observations have significantly improved our understanding of the characteristics, formation, and evolution of asteroids in general.

OSIRIS-REx Asteroid Sample-Return Mission

NASA Astrophysics Data System (ADS)

DellaGiustina, D. N.; Lauretta, D. S.

2016-12-01

Launching in September 2016, the primary objective of the Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) mission is to return a pristine sample of asteroid (101955) Bennu to Earth for sample analysis. Bennu is a carbonaceous primitive near-Earth object, and is expected to be rich in volatile and organic material leftover from the formation of the Solar System. OSIRIS-REx will return a minimum of 60 g of bulk surface material from this body using a novel "touch-and-go" sample acquisition mechanism. Analyses of these samples will provide unprecedented knowledge about presolar history, from the initial stages of planet formation to the origin of life. Before sample acquisition, OSIRIS-REx will perform global mapping of Bennu, detailing the asteroid's composition and texture, resolving surface features, revealing its geologic and dynamic history, and providing context for the returned samples. The mission will also document the sampling site in situ at sub-centimeter scales, as well as the asteroid sampling event. In addition, OSIRIS-REx will measure the Yarkovsky effect, a non-Keplerian force affecting the orbit of this potentially hazardous asteroid, and provide a ground truth data for the interpretation of telescopic observations of carbonaceous asteroids.

Shaping planetary nebulae with jets in inclined triple stellar systems

NASA Astrophysics Data System (ADS)

Akashi, Muhammad; Soker, Noam

2017-08-01

We conduct three-dimensional hydrodynamical simulations of two opposite jets launched obliquely to the orbital plane around an asymptotic giant branch (AGB) star and within its dense wind, and demonstrate the formation of a 'messy' planetary nebula (PN), namely a PN lacking any type of symmetry (I.e. highly irregular). In building the initial conditions, we assume that a tight binary system orbits the AGB star and that the orbital plane of the tight binary system is inclined to the orbital plane of the binary system and the AGB star (the triple system plane). We further assume that the accreted mass on to the tight binary system forms an accretion disc around one of the stars and that the plane of the disc is tilted to the orbital plane of the triple system. The highly asymmetrical and filamentary structures that we obtain support the notion that messy PNe might be shaped by triple stellar systems.

The Violent Collisional History of Asteroid 4 Vesta

NASA Astrophysics Data System (ADS)

Marchi, S.; McSween, H. Y.; O'Brien, D. P.; Schenk, P.; De Sanctis, M. C.; Gaskell, R.; Jaumann, R.; Mottola, S.; Preusker, F.; Raymond, C. A.; Roatsch, T.; Russell, C. T.

2012-05-01

Vesta is a large differentiated rocky body in the main asteroid belt that accreted within the first few million years after the formation of the earliest solar system solids. The Dawn spacecraft extensively imaged Vesta’s surface, revealing a collision-dominated history. Results show that Vesta’s cratering record has a strong north-south dichotomy. Vesta’s northern heavily cratered terrains retain much of their earliest history. The southern hemisphere was reset, however, by two major collisions in more recent times. We estimate that the youngest of these impact structures, about 500 kilometers across, formed about 1 billion years ago, in agreement with estimates of Vesta asteroid family age based on dynamical and collisional constraints, supporting the notion that the Vesta asteroid family was formed during this event.

ATLAS: Finding the Nearest Asteroids

NASA Astrophysics Data System (ADS)

Heinze, Aren; Tonry, John L.; Denneau, Larry; Stalder, Brian

2017-10-01

The Asteroid Terrestrial-impact Last Alert System (ATLAS) became fully operational in June 2017. Our two robotic, 0.5 meter telescopes survey the whole accessible sky every two nights from the Hawaiian mountains of Haleakala and Mauna Loa. With sensitivity to magnitude 19.5 over a field of 30 square degrees, we discover several bright near-Earth objects every month - particularly fast moving asteroids, which can slip by other surveys that scan the sky more slowly. Several important developments in 2017 have enhanced our sensitivity to small, nearby asteroids and potential impactors. We report on these developments - including optical adjustments, automated screening of detections, closer temporal spacing of images, and tolerance for large deviations from Great Circle motion on the sky - and we describe their effect in terms of measuring and discovering real objects.

Results of the 2016 Mexican Asteroid Photometry Campaign

NASA Astrophysics Data System (ADS)

Sada, Pedro V.; Olguin, Lorenzo; Saucedo, Julio C.; Loera-Gonzalez, Pablo; Cantu-Sanchez, Laura; Garza, Jaime R.; Ayala-Gomez, Sandra A.; Aviles, Andres; Perez-Tijerina, Eduardo; Navarro-Meza, Samuiel; Silva, J. S.; Reyes-Ruiz, Mauricio; Segura-Sosa, Juan; Lopez-Valdivia, Ricardo; Alvarez-Santana, F.

2017-07-01

We report the results of the 2016 Mexican Asteroid Photometry Campaign. This year observers from seven different research institutions carried out 34 nights of observations at three Mexican observatories. An uncertain, but long, period of 115.108 ± 0.014 h was estimated for 703 Noëmi from sparse data. A nearly complete lightcurve was obtained for 1305 Pongola (P = 8.0585 ± 0.0003 h). Asteroid 2535 Hämeenlinna turned out to be a binary system where the primary exhibits a rotation period of 3.2311 ± 0.0001 h and the secondary shows an orbital period of 21.20 ± 0.004 h. Asteroid 4775 Hansen (P = 3.1186 ± 0.0001 h) was well observed and showed variations of its lightcurve between two sets of observations separated by about six weeks.

Electric solar-wind sail for asteroid touring missions and planetary protection

NASA Astrophysics Data System (ADS)

Janhunen, P.

2014-07-01

The electric solar-wind sail (electric sail, E-sail [1,2]) is a relatively new concept for moving around in the solar system without consuming propellant and by using the thrust provided by the natural solar wind to produce propulsion. The E-sail is based on deploying, using the centrifugal force, a set of long, thin metallic tethers and charging them to high positive voltage by actively removing negative charge from the system by an electron gun. To make the tethers resistant towards inevitable wire cuts by micrometeoroids, they must be made by bonding from multiple (typically 4) thin (25--50 μ m) aluminium wires. Production of the tethers was a technical challenge which was recently overcome. According to present numerical estimates, the E-sail could produce up to 1 N of propellantless thrust out of less than 200 kg package which is enough to give characteristic acceleration of 1 mm/s^2 to a spacecraft weighing 1 tonne, thus producing 30 km/s of delta-v per year. The thrust scales as ˜ 1/r where r is the solar distance. There are ways to control and vector the thrust enough to enable inward and outward spiralling missions in the solar system. The E-sail working principle has been indirectly measured in a laboratory, and ESTCube-1 CubeSat experiment is underway in orbit (in late March 2014 it was waiting to be started) to measure the E-sail thrust acting on a short 10-m long tether. A full-scale mission requires ˜ 1000 km of tether altogether (weighing ˜10 kg). The production of a 1-km piece of tether has been demonstrated in laboratory [3]. If the E-sail holds up its present promise, it would be ideally suited for asteroid missions because it enables production of similar level of thrust than ion engines, but needs only a small fraction of the electric power and never runs out of propellant because it does not use any (the ''propellant'' being the natural solar-wind plasma flow). Here we consider especially a mission which would tour the asteroid belt for a long time, moving from asteroid to asteroid in a bit similar way as, e.g., Mars rovers move from rock to rock on the planet's surface. After starting from the Earth, the mission would slowly spiral outward, making rendezvous with interesting asteroids along the way, as well as flybys or even a larger number of asteroids as opportunities arise. The spacecraft would do remote sensing of the bodies and perhaps also deploy small CubeSat-sized expendable landers on them (the mother spacecraft cannot land on an asteroid or else it would lose the E-sail tethers). The mission would first explore near-Earth objects, then pass through the main belt and end up with the Trojans, exploring asteroids in rendezvous and flyby modes all the time. Asteroids in roughly circular orbits and at low inclination would be the easiest and most likely targets for rendezvous mode encounters, while there would be less restrictions for flyby mode observations. Besides for pure asteroid science, the E-sail could also be used for planetary protection, either through direct propulsive deflection of a dangerous asteroid [4] or by accelerating a relatively lightweight impactor spacecraft to a retrograde orbit and in that way maximizing the available deflecting impact energy for given impactor mass. E-sails could take a number of such impactors to retrograde storage orbits from which they could be commanded to impact a dangerous asteroid with relatively short warning time. Such impactor fleet would not be dangerous to the Earth because the vehicles can be designed to burn completely in the atmosphere, in the unlikely event that due to some mishap one of them would collide with the Earth. The E-sail has potentially large applicability to asteroids as it promises ''free'' transportation in the solar system. As a next step, a solar-wind test mission is needed to demonstrate the technology in the authentic environment.

Roles of Shape and Internal Structure in Rotational Disruption of Asteroids

NASA Astrophysics Data System (ADS)

Hirabayashi, Masatoshi; Scheeres, Daniel Jay

2015-08-01

An active research area over the last decade has been to explore configuration changes of rubble pile asteroids due to rotationally induced disruption, initially driven by the remarkable fact that there is a spin period threshold of 2 hr for asteroids larger than a few hundred meters in size. Several different disruption modes due to rapid rotation can be identified, as surface shedding, fission and failure of the internal structure. Relevant to these discussions are many observations of asteroid shapes that have revealed a diversity of forms such as oblate spheroids with equatorial ridges, strongly elongated shapes and contact binaries, to say nothing of multi-body systems. With consideration that rotationally induced deformation is one of the primary drivers of asteroid evolution, we have been developing two techniques for investigating the structure of asteroids, while accounting for their internal mechanical properties through plastic theory. The first technique developed is an analytical model based on limit analysis, which provides rigorous bounds on the asteroid mechanical properties for their shapes to remain stable. The second technique applies finite element model analysis that accounts for plastic deformation. Combining these models, we have explored the correlation between unique shape features and failure modes. First, we have been able to show that contact binary asteroids preferentially fail at their narrow necks at a relatively slow spin period, due to stress concentration. Second, applying these techniques to the breakup event of active asteroid P/2013 R3, we have been able to develop explicit constraints on the cohesion within rubble pile asteroids. Third, by probing the effect of inhomogeneous material properties, we have been able to develop conditions for whether an oblate body will fail internally or through surface shedding. These different failure modes can be tested by measuring the density distribution within a rubble pile body through determination of its gravity field. This talk will explore these different modes of failure and motivate divergent theories of failure that depend on properties of rubble piles.

Shapes, rotation, and pole solutions of the selected Hilda and Trojan asteroids

NASA Astrophysics Data System (ADS)

Gritsevich, Maria; Sonnett, Sarah; Torppa, Johanna; Mainzer, Amy; Muinonen, Karri; Penttilä, Antti; Grav, Thomas; Masiero, Joseph; Bauer, James; Kramer, Emily

2017-04-01

Binary asteroid systems contain key information about the dynamical and chemical environments in which they formed. For example, determining the formation environments of Trojan and Hilda asteroids (in 1:1 and 3:2 mean-motion resonance with Jupiter, respectively) will provide critical constraints on how small bodies and the planets that drive their migration must have moved throughout Solar System history, see e.g. [1-3]. Therefore, identifying and characterizing binary asteroids within the Trojan and Hilda populations could offer a powerful means of discerning between Solar System evolution models. Dozens of possibly close or contact binary Trojans and Hildas were identified within the data obtained by NEOWISE [4]. Densely sampled light curves of these candidate binaries have been obtained in order to resolve rotational light curve features that are indicative of binarity (e.g., [5-7]). We present analysis of the shapes, rotation, and pole solutions of some of the follow-up targets observed with optical ground-based telescopes. For modelling the asteroid photometric properties, we use parameters describing the shape, surface light scattering properties and spin state of the asteroid. Scattering properties of the asteroid surface are modeled using a two parameter H-G12 magnitude system. Determination of the initial best-fit parameters is carried out by first using a triaxial ellipsoid shape model, and scanning over the period values and spin axis orientations, while fitting the other parameters, after which all parameters were fitted, taking the initial values for spin properties from the spin scanning. In addition to the best-fit parameters, we also provide the distribution of the possible solution, which should cover the inaccuracies of the solution, caused by the observing errors and model. The distribution of solutions is generated by Markov-Chain Monte Carlo sampling the spin and shape model parameters, using both an ellipsoid shape model and a convex model, Gaussian curvature of which is defined as a spherical harmonics series [8]. References: [1] Marzari F. and Scholl H. (1998), A&A, 339, 278. [2] Morbidelli A. et al. (2005), Nature, 435, 462. [3] Nesvorny D. et al. (2013), ApJ, 768, 45. [4] Sonnett S. et al. (2015), ApJ, 799, 191. [5] Behrend R. et al. (2006), A&A, 446, 1177. [6] Lacerda P. and Jewitt D. C. (2007), AJ, 133, 1393. [7] Oey J. (2016), MPB, 43, 45. [8] Muinonen et al., ACM 2017.

On Possibility of Direct Asteroid Deflection by Electric Solar Wind Sail

NASA Astrophysics Data System (ADS)

Merikallio, Sini; Janhunen, Pekka

2010-05-01

The Electric Solar Wind Sail (E-sail) is a new propulsion method for interplanetary travel which was invented in 2006 and is currently under development. The E-sail uses charged tethers to extract momentum from the solar wind particles to obtain propulsive thrust. According to current estimates, the E-sail is 2-3 orders of magnitude better than traditional propulsion methods (chemical rockets and ion engines) in terms of produced lifetime-integrated impulse per propulsion system mass. Here we analyze the problem of using the E-sail for directly deflecting an Earth-threatening asteroid. The problem then culminates into how to attach the E-sail device to the asteroid. We assess a number of alternative attachment strategies and arrive at a recommendation of using the gravity tractor method because of its workability for a wide variety of asteroid types. We also consider possible techniques to scale up the E-sail force beyond the baseline one Newton level to deal with more imminent or larger asteroid or cometary threats. As a baseline case we consider a 3 million ton asteroid which can be deflected with a baseline 1 N E-sail in 5-10 years. Once developed, the E-sail would appear to provide a safe and reasonably low-cost way of deflecting dangerous asteroids and other heavenly bodies in cases where the collision threat becomes known several years in advance.

SEM and TEM Observation of the Surfaces of the Fine-Grained Particles Retrieved from the Muses-C Regio on the Asteroid 25413 Itokawa

NASA Technical Reports Server (NTRS)

Noguchi, T.; Nakamura, T.; Zolensky, Michael E.; Tanaka, M.; Hashimoto, T.; Konno, M.; Nakato, A.; Ogami, T.; Fujimura, A.; Abe, M.;

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

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.

The Mid-plane of the Main Asteroid Belt

NASA Astrophysics Data System (ADS)

Cambioni, Saverio; Malhotra, Renu

2018-03-01

We measure the mid-plane of the main asteroid belt by using the observational data of a nearly complete and unbiased sample of asteroids and find that it has inclination \\bar{I}=0\\buildrel{\\circ}\\over{.} 93+/- 0\\buildrel{\\circ}\\over{.} 04 and longitude of ascending node \\bar{{{Ω }}}=87\\buildrel{\\circ}\\over{.} 6+/- 2\\buildrel{\\circ}\\over{.} 6 (in J2000 ecliptic-equinox coordinate system). This plane differs significantly from previously published measurements, and it is also distinctly different than the solar system’s invariable plane as well as Jupiter’s orbit plane. The mid-plane of the asteroid belt is theoretically expected to be a slightly warped sheet whose local normal is controlled by the gravity of the major planets. Specifically, its inclination and longitude of ascending node varies with semimajor axis and time (on secular timescales) and is defined by the forced solution of secular perturbation theory; the ν 16 nodal secular resonance is predicted to cause a significant warp of the mid-plane in the inner asteroid belt. We test the secular theory by measuring the current location of the asteroids’ mid-plane in finer semimajor axis bins. We find that the measured mid-plane in the middle and outer asteroid belt is consistent, within the 3σ confidence level, with the prediction of secular perturbation theory, but a notable discrepancy is present in the inner asteroid belt near ∼2 au.

A Survey of Rotation Lightcurves of Small Jovian Trojan Asteroids in the L4 Cloud

NASA Astrophysics Data System (ADS)

French, Linda M.; Stephens, Robert; Warner, Brian; James, David; Rohl, Derrick; Connour, Kyle

2017-10-01

Jovian Trojan asteroids are of interest both as objects in their own right and as possible relics of Solar System formation. Several lines of evidence support a common origin for, and possible hereditary link between, Jovian Trojan asteroids and cometary nuclei. Asteroid lightcurves give information about processes that have affected a group of asteroids including their density. Due to their distance and low albedos, few comet-sized Trojans have been studied. We have been carrying out a survey of Trojan lightcurve properties comparing small Trojan asteroids with comets (French et al 2015). We present new lightcurve information for 39 Trojans less than about 35 km in diameter. We report our latest results and compare them with results from the sparsely-sampled lightcurves from the Palomar Transient Factory (Waszazak et al., Chang et al. 2015). The minimum densities for objects with complete lightcurves are estimated and are found to becomparable to those measured for cometary nuclei. A significant fraction (~40%) of thisobserved small Trojan population rotates slowly (P > 24 hours), with measured periods as over 500 hours (Waszczak et al 2015). The excess of slow rotators may be due to the YORP effect. Results of the Kolmogorov-Smirnov test suggest that the distribution of Trojan rotation rates is dissimilar to those of Main Belt Asteroids of the same size.

Triple-effect absorption refrigeration system with double-condenser coupling

DOEpatents

DeVault, R.C.; Biermann, W.J.

1993-04-27

A triple effect absorption refrigeration system is provided with a double-condenser coupling and a parallel or series circuit for feeding the refrigerant-containing absorbent solution through the high, medium, and low temperature generators utilized in the triple-effect system. The high temperature condenser receiving vaporous refrigerant from the high temperature generator is double coupled to both the medium temperature generator and the low temperature generator to enhance the internal recovery of heat within the system and thereby increase the thermal efficiency thereof.

Triple-effect absorption refrigeration system with double-condenser coupling

DOEpatents

DeVault, Robert C.; Biermann, Wendell J.

1993-01-01

A triple effect absorption refrigeration system is provided with a double-condenser coupling and a parallel or series circuit for feeding the refrigerant-containing absorbent solution through the high, medium, and low temperature generators utilized in the triple-effect system. The high temperature condenser receiving vaporous refrigerant from the high temperature generator is double coupled to both the medium temperature generator and the low temperature generator to enhance the internal recovery of heat within the system and thereby increase the thermal efficiency thereof.

Analysis of IRAS solar system dust data

NASA Technical Reports Server (NTRS)

Dermott, S. F.; Nicholson, P. D.

1991-01-01

Data in the Infrared Astronomical Satellite (IRAS) Zodiacal History File were analyzed to extract dust band locations and peak brightness measurements from approximately 1,000 individual IRAS scans. The study had three goals. One was to show that the prominent solar system dust bands are associated with Hirayama asteroid families and thus that collisions between asteroids account for a significant fraction of the particles in the zodiacal cloud. Recent work suggests that while the Hirayama families are a major source of the dust in the bands, there may also be contributions from two or three smaller, more recently recognized asteroid families. A second goal was to show that there is evidence in the IRAS dust data for the transport of particles from asteroid belt to the Earth by Poynting-Robertson light drag and thus account for the fact that asteroid particles are collected in the Earth's stratosphere. Results of the study will confirm the location of the dust bands within the inner asteroid belt, and show conclusively that the material seen by IRAS is now spread over a wide range of distances from the sun. The third goal was to construct a model of the background zodiacal cloud that satisfies the proper dynamical constraints. Figures are provided to show the scans processed to remove zodiacal background and Galactic signals, and the resulting polynomial fits to the 25 micron scan. The latter provided objective estimates of band widths, peak locations, and peak fluxes. Modelling and analysis of the resulting band data has been presented at several conferences and is the subject of a number of forthcoming papers.

Solar wind tans young asteroids

NASA Astrophysics Data System (ADS)

2009-04-01

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.

The Origin of Apollo Objects

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

Perlmutter, Saul

1984-03-29

The source of the Earth-orbit-crossing asteroids has been much debated. (This class of asteroidal bodies includes the Apollo, Aten, and some Amor objects, each with its own orbital characteristics; we shall use the term Apollo objects to mean all Earth-crossers.) It is difficult to find a mechanism which would create new Apollo objects at a sufficient rate to balance the loss due to collision with planets and ejection from the solar system, and thus explain the estimated steady-state number. A likely source is the main asteroid belt, since it has similar photometric characteristics. There are gaps in the main beltmore » which correspond to orbits resonant with the orbits of Jupiter and Saturn, and it has been shown that the resonances can perturb a body into an Earth-crossing orbit. Apollo objects could thus be generated when random collisions between asteroids in the main belt sent fragments into these resonant orbits. Calculations of the creation rate from these random collisions, however, yielcl numbers too low by a factor of four. This rate could be significantly lower given the uncertainty in the efficiency of the resonance mechanism. As an alternative, it was suggested that the evaporation of a comet's volatile mantle as it passes near the sun could provide enough non-gravitational force to move the comet into an orbit with aphelion inside of Jupiter's orbit, and thus safe from ejection from the solar system. The probability of such an event occurring is unknown, although the recent discovery of the 'asteroid' 1983 TB, with an orbit matching that of the Geminid meteor shower, suggests that such a mechanism has occurred at least once. New evidence from paleontology and geophysics, however, suggests a better solution to the problem of the source of the Apollos. M. Davis, P. Hut, and R. A. Muller recently proposed that an unseen companion to the sun passes through the Oort cloud every 28 million years, sending a shower of comets to the Earth; this provides an explanation for the periodicity of the fossil record of extinctions found by D. M. Raup and J. J. Sepkoski. W. Alvarez and R. A. Muller have shown that the craters on the earth have an age distribution with a periodicity and phase consistent with this hypothesis. These periodic comet showers would of course pass through the entire solar system, colliding with other bodies besides the earth. When the target is the asteroid belt, many small comets will have sufficient kinetic energy to disrupt large asteroids. This will generate many more fragments in the resonant orbits than would be generated by random collisions of asteroids with each other, and hence more Apollo objects. In this report, we shall calculate approximately (A) the number of comets per shower which cross the asteroid belt, (B) the probability of collisions with a single asteroid per shower, (C) the number of fragments with radius > 0.5 km which reach Apollo orbits, and (D) the current expected number of Apollos derived from comet/asteroid collisions. Given conservative assumptions, the calculated number is in agreement with observations.« less

Recovery and normalization of triple coincidences in PET

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

Lage, Eduardo, E-mail: elage@mit.edu; Parot, Vicente; Dave, Shivang R.

2015-03-15

Purpose: Triple coincidences in positron emission tomography (PET) are events in which three γ-rays are detected simultaneously. These events, though potentially useful for enhancing the sensitivity of PET scanners, are discarded or processed without special consideration in current systems, because there is not a clear criterion for assigning them to a unique line-of-response (LOR). Methods proposed for recovering such events usually rely on the use of highly specialized detection systems, hampering general adoption, and/or are based on Compton-scatter kinematics and, consequently, are limited in accuracy by the energy resolution of standard PET detectors. In this work, the authors propose amore » simple and general solution for recovering triple coincidences, which does not require specialized detectors or additional energy resolution requirements. Methods: To recover triple coincidences, the authors’ method distributes such events among their possible LORs using the relative proportions of double coincidences in these LORs. The authors show analytically that this assignment scheme represents the maximum-likelihood solution for the triple-coincidence distribution problem. The PET component of a preclinical PET/CT scanner was adapted to enable the acquisition and processing of triple coincidences. Since the efficiencies for detecting double and triple events were found to be different throughout the scanner field-of-view, a normalization procedure specific for triple coincidences was also developed. The effect of including triple coincidences using their method was compared against the cases of equally weighting the triples among their possible LORs and discarding all the triple events. The authors used as figures of merit for this comparison sensitivity, noise-equivalent count (NEC) rates and image quality calculated as described in the NEMA NU-4 protocol for the assessment of preclinical PET scanners. Results: The addition of triple-coincidence events with the authors’ method increased peak NEC rates of the scanner by 26.6% and 32% for mouse- and rat-sized objects, respectively. This increase in NEC-rate performance was also reflected in the image-quality metrics. Images reconstructed using double and triple coincidences recovered using their method had better signal-to-noise ratio than those obtained using only double coincidences, while preserving spatial resolution and contrast. Distribution of triple coincidences using an equal-weighting scheme increased apparent system sensitivity but degraded image quality. The performance boost provided by the inclusion of triple coincidences using their method allowed to reduce the acquisition time of standard imaging procedures by up to ∼25%. Conclusions: Recovering triple coincidences with the proposed method can effectively increase the sensitivity of current clinical and preclinical PET systems without compromising other parameters like spatial resolution or contrast.« less

ASPECT spectral imaging satellite proposal to AIDA/AIM CubeSat payload

NASA Astrophysics Data System (ADS)

Kohout, Tomas; Näsilä, Antti; Tikka, Tuomas; Penttilä, Antti; Muinonen, Karri; Kestilä, Antti; Granvik, Mikael; Kallio, Esa

2016-04-01

ASPECT (Asteroid Spectral Imaging Mission) is a part of AIDA/AIM project and aims to study the composition of the Didymos binary asteroid and the effects of space weathering and shock metamorphism in order to gain understanding of the formation and evolution of the Solar System. The joint ESA/NASA AIDA (Asteroid Impact & Deflection Assessment) mission to binary asteroid Didymos consists of AIM (Asteroid Impact Mission, ESA) and DART (Double Asteroid Redirection Test, NASA). DART is targeted to impact Didymos secondary component (Didymoon) and serve as a kinetic impactor to demonstrate deflection of potentially hazardous asteroids. AIM will serve as an observational spacecraft to evaluate the effects of the impact and resulting changes in the Didymos dynamic parameters. The AIM mission will also carry two CubeSat miniaturized satellites, released in Didymoon proximity. This arrangement opens up a possibility for secondary scientific experiments. ASPECT is one of the proposed CubeSat payloads. Whereas Didymos is a space-weathered binary asteroid, the DART impactor is expected to produce a crater and excavate fresh material from the secondary component (Didymoon). Spectral comparison of the mature surface to the freshly exposed material will allow to directly deter-mine space weathering effects. It will be also possible to study spectral shock effects within the impact crater. ASPECT will also demonstrate for the first time the joint spacecraft - CubeSat operations in asteroid proximity and miniature spectral imager operation in deep-space environment. Science objectives: 1. Study of the surface composition of the Didymos system. 2. Photometric observations (and modeling) under varying phase angle and distance. 3. Study of space weathering effects on asteroids (comparison of mature / freshly exposed material). 4. Study of shock effects (spectral properties of crater interior). 5. Observations during the DART impact. Engineering objectives: 1. Demonstration of CubeSat semi-autonomous operations in deep space environment. 2. Navigation in the vicinity of a binary asteroid. 3. Demonstration of a satellite survival during impact. 4. Demonstration of joint spacecraft - CubeSat operations. ASPECT is a 3U CubeSat (size of 3 units, Fig. 1) equipped with a spectral imager from 500 nm to 1600 nm (spatial resolution < 2 m, spectral resolution 10 - 30 nm; VIS channel 512 x 512 pixels, NIR channel 256 x 256 pixels), and a non-imaging spectrometer from 1600 - 2500 nm. The design is based on the Aalto-1 CubeSat Spectral Imager heritage. ASPECT will also demonstrate the capabilities of a CubeSat and a miniature spectral imager for the first time in deep-space environment. Acknowledgements: This work is done under Sys-Nova: R&D Studies Competition for Innovation contract with ESA.

The Mission Accessibility of Near-Earth Asteroids

NASA Technical Reports Server (NTRS)

Barbee, Brent W.; Abell, P. A.; Adamo, D. R.; Mazanek, D. D.; Johnson, L. N.; Yeomans, D. K.; Chodas, P. W.; Chamberlin, A. B.; Benner, L. A. M.; Taylor, P.;

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.

The Collisional Evolution of the Main Asteroid Belt

NASA Astrophysics Data System (ADS)

Bottke, W. F.; Brož, M.; O'Brien, D. P.; Campo Bagatin, A.; Morbidelli, A.; Marchi, S.

Collisional and dynamical models of the main asteroid belt allow us to glean insights into planetesimal- and planet-formation scenarios as well as how the main belt reached its current state. Here we discuss many of the processes affecting asteroidal evolution and the constraints that can be used to test collisional model results. We argue the main belt's wavy size-frequency distribution for diameter D < 100-km asteroids is increasingly a byproduct of comminution as one goes to smaller sizes, with its shape a fossil-like remnant of a violent early epoch. Most D > 100-km asteroids, however, are primordial, with their physical properties set by planetesimal formation and accretion processes. The main-belt size distribution as a whole has evolved into a collisional steady state, and it has possibly been in that state for billions of years. Asteroid families provide a critical historical record of main-belt collisions. The heavily depleted and largely dispersed "ghost families," however, may hold the key to understanding what happened in the primordial days of the main belt. New asteroidal fragments are steadily created by both collisions and mass shedding events via YORP spinup processes. A fraction of this population, in the form of D < 30 km fragments, go on to escape the main belt via the Yarkovsky/YORP effects and gravitational resonances, thereby creating a quasi-steady-state population of planet-crossing and near-Earth asteroids. These populations go on to bombard all inner solar system worlds. By carefully interpreting the cratering records they produce, it is possible to constrain how portions of the main-belt population have evolved with time.

Asteroid Deflection: How, Where and When?

NASA Astrophysics Data System (ADS)

Fargion, D.

2008-10-01

To deflect impact-trajectory of massive and spinning km^3 asteroid by a few terrestrial radiuses one need a large momentum exchange. The dragging of huge spinning bodies in space by external engine seems difficult or impossible. Our solution is based on the landing of multi screw-rockets, powered by mini-nuclear engines, on the body, that dig a small fraction of the soil surface to use as an exhaust propeller, ejecting it vertically in phase among themselves. Such a mass ejection increases the momentum exchange, their number redundancy guarantees the stability of the system. The slow landing (below ≃ 40 cm s^{-1}) of each engine-unity at those very low gravity field, may be achieved by safe rolling and bouncing along the surface. The engine array tuned activity, overcomes the asteroid angular velocity. Coherent turning of the jet heads increases the deflection efficiency. A procession along its surface may compensate at best the asteroid spin. A small skin-mass (about 2×10^4 tons) may be ejected by mini-nuclear engines. Such prototypes may also build first safe galleries for humans on the Moon. Conclusive deflecting tests might be performed on remote asteroids. The incoming asteroid 99942 Apophis (just 2% of km^3) may be deflected safely a few Earth radiuses. Its encounter maybe not just a hazard but an opportunity, learning how to land, to dig, to build and also to nest safe human station inside. Asteroids amplified deflections by gravity swing may be driven into longest planetary journeys, beginning i.e. with the preliminary landing of future missions on Mars' moon-asteroid Phobos or Deimos.

Interrelating meteorite and asteroid spectra at UV-Vis-NIR wavelengths using novel multiple-scattering methods

NASA Astrophysics Data System (ADS)

Martikainen, Julia; Penttilä, Antti; Gritsevich, Maria; Muinonen, Karri

2017-10-01

Asteroids have remained mostly the same for the past 4.5 billion years, and provide us information on the origin, evolution and current state of the Solar System. Asteroids and meteorites can be linked by matching their respective reflectance spectra. This is difficult, because spectral features depend strongly on the surface properties, and meteorite surfaces are free of regolith dust present in asteroids. Furthermore, asteroid surfaces experience space weathering which affects their spectral features.We present a novel simulation framework for assessing the spectral properties of meteorites and asteroids and matching their reflectance spectra. The simulations are carried out by utilizing a light-scattering code that takes inhomogeneous waves into account and simulates light scattering by Gaussian-random-sphere particles large compared to the wavelength of the incident light. The code uses incoherent input and computes phase matrices by utilizing incoherent scattering matrices. Reflectance spectra are modeled by combining olivine, pyroxene, and iron, the most common materials that dominate the spectral features of asteroids and meteorites. Space weathering is taken into account by adding nanoiron into the modeled asteroid spectrum. The complex refractive indices needed for the simulations are obtained from existing databases, or derived using an optimization that utilizes our ray-optics code and the measured spectrum of the material.We demonstrate our approach by applying it to the reflectance spectrum of (4) Vesta and the reflectance spectrum of the Johnstown meteorite measured with the University of Helsinki integrating-sphere UV-Vis-NIR spectrometer.Acknowledgments. The research is funded by the ERC Advanced Grant No. 320773 (SAEMPL).

Precise Distances for Main-belt Asteroids in Only Two Nights

NASA Astrophysics Data System (ADS)

Heinze, Aren N.; Metchev, Stanimir

2015-10-01

We present a method for calculating precise distances to asteroids using only two nights of data from a single location—far too little for an orbit—by exploiting the angular reflex motion of the asteroids due to Earth’s axial rotation. We refer to this as the rotational reflex velocity method. While the concept is simple and well-known, it has not been previously exploited for surveys of main belt asteroids (MBAs). We offer a mathematical development, estimates of the errors of the approximation, and a demonstration using a sample of 197 asteroids observed for two nights with a small, 0.9-m telescope. This demonstration used digital tracking to enhance detection sensitivity for faint asteroids, but our distance determination works with any detection method. Forty-eight asteroids in our sample had known orbits prior to our observations, and for these we demonstrate a mean fractional error of only 1.6% between the distances we calculate and those given in ephemerides from the Minor Planet Center. In contrast to our two-night results, distance determination by fitting approximate orbits requires observations spanning 7-10 nights. Once an asteroid’s distance is known, its absolute magnitude and size (given a statistically estimated albedo) may immediately be calculated. Our method will therefore greatly enhance the efficiency with which 4m and larger telescopes can probe the size distribution of small (e.g., 100 m) MBAs. This distribution remains poorly known, yet encodes information about the collisional evolution of the asteroid belt—and hence the history of the Solar System.

Dynamical history of the asteroid belt and implications for terrestrial pla net bombardment

NASA Astrophysics Data System (ADS)

Minton, David Andrew

The main asteroid belt spans ~ 2-4 AU in heliocentric distance and is sparsely populated by rocky debris. The dynamical structure of the main belt records clues to past events in solar system history. Evidence from the structure of the Kuiper belt, an icy debris belt beyond Neptune, suggests that the giant planets were born in a more compact configuration and later experienced planetesimal-driven planet migration. Giant planet migration caused both mean motion and secular resonances to sweep across the main asteroid belt, raising the eccentricity of asteroids into planet-crossing orbits and depleting the belt. I show that the present-day semimajor axis and eccentricity distributions of large main belt asteroids are consistent with excitation and depletion due to resonance sweeping during the epoch of giant planet migration. I also use an analytical model of the sweeping of the n 6 secular resonance, to set limits on the migration speed of Saturn. After planet migration, dynamical chaos became the dominant loss mechanism for asteroids with diameters D [Special characters omitted.] 10 km in the current asteroid belt. I find that the dynamical loss history of test particles from this region is well described with a logarithmic decay law. My model suggests that the rate of impacts from large asteroids may have declined by a factor of three over the last ~ 3 Gy, and that the present-day impact flux of D > 10 km objects on the terrestrial planets is roughly an order of magnitude less than estimates used in crater chronologies and impact hazard risk assessments. Finally, I have quantified the change in the solar wind 6 Li/ 7 Li ratio due to the estimated in-fall of chondritic material and enhanced dust production during the epoch of planetesimal-driven giant planet migration. The solar photosphere is currently highly depleted in lithium relative to chondrites, and 6 Li is expected to be far less abundant in the sun than 7 Li due to the different nuclear reaction rates of the two isotopes. Evidence for a short- lived impact cataclysm that affected the entire inner solar system may be found in the composition of implanted solar wind particles in lunar regolith.

Spin Rate Diversity Amongst Ten-meter Class Near Earth Asteroids

NASA Astrophysics Data System (ADS)

Ryan, William; Ryan, Eileen V.

2016-10-01

The spin rates of small asteroids can provide insight into their mechanical structure, origin, and subsequent evolution. This is of more than just scientific interest since these are also the objects that will hit the Earth most frequently. Early statistics [Pravec and Harris, 2000] for Near Earth Asteroids (NEAs) with diameters of ~100 meters or less had resulted in the conclusion that many are rotating more rapidly than feasible for a gravitationally bound system of constituent components (i.e, 'rubble piles'). However, more recent studies [Holsapple, 2007; Scheeres et al. 2010] have focused on how non-gravitational cohesion mechanisms do not necessarily rule out a rubble pile structure for fast spin rate bodies. To further study this issue, we will report on the recent spin rate results for the smallest asteroids observed as part of our ongoing NEA target-of-opportunity characterization research [Ryan and Ryan, 2016] conducted using the Magdalena Ridge Observatory's 2.4-meter telescope.Spin rates determined by this program plus results from the current lightcurve database [Warner et al. 2016] indicate that the very smallest NEAs with H>29 rotate with periods of minutes or less. This implies that these objects possess significant strength, hinting that they are likely examples of truly monolithic fragments. However, our observations also show a great diversity in rotation periods for asteroids that are only slightly larger. In particular, the H~28.6 asteroids 2016 CC136 and 2016 CG18 were observed to rotate with periods approaching or exceeding ~2 hours, with the latter showing a tumbling behavior. In a subset of our database that includes 22 asteroids with H~27.5 (~10 meters) or greater, a full range of periods from less than a minute to greater than 2 hours (close to the minimal period of a self-gravitating system), have been identified. Moreover, at least three of these are in a tumbling state with multiple periods clearly identified, implying constraints on their ages. The overall diversity in the observed spins in our database will be discussed in the context of better understanding internal body strengths required for the smallest asteroids.

The GTC mid-infrared spectroscopic program of primitive outer-belt asteroids

NASA Astrophysics Data System (ADS)

Licandro, J.; Alvarez-Iglesias, C. Carlos; Cabrera-Lavers, A.; Ali-Lagoa, V.; Pinilla-Alonso, N.; Campins, H.; de Leon, J.; Kelley, M.

2014-07-01

Asteroids in the outer edge of the asteroid belt (Cybeles, Hildas, and Jupiter Trojans) may provide a number of clues to the origin and evolution of the asteroid belt and the formation of our planetary system. They have a pristine composition, experienced little heating and may contain a significant fraction of ice in their interiors. The origin of these populations is still under debate. Levison et al. (2009) suggested that a large fraction of these bodies are transneptunian objects (TNOs) moved to these resonances in an early epoch of the Solar System called the ''Late Heavy Bombardment'' (LHB). To compare the physical properties of these asteroid populations with TNOs and comets is thus a strong test of dynamical models. In mid 2013, we started a mid-infrared photometric and spectroscopic program in the N-band using the CANARICAM camera-spectrograph at the 10.4-m GTC telescope at the ''Roque de los Muchachos'' Obserbatory (Canary Islands, Spain). We aim to study the surface composition and key properties such as radius, albedo, and thermal inertia based on their low-resolution 8--13-micron spectra and N-band photometry. We already obtained the spectra of 5 objects, that of (225) Henrieta is shown as an example in the Figure. The three published spectra of Trojan asteroids (Emery et al. 2006) and of (65) Cybele (Licandro et al. 2011) exhibit clear emissivity features from which the compositional and physical properties can be inferred. The spectra of these objects strongly resemble one another, presenting an emission plateau due to silicates at about 9.1-11.5 microns (the Si-O stretch fundamental). Fine-grained silicates in a very porous (fairly castle) structure, and no other mineral group (Emery et al. 2006, Vernazza et al. 2012), reproduce the major features of the Trojans and Cybele asteroid spectra. In this work, we present the preliminary results of our observational program including the N-band spectra, size, and albedo of the already observed 5 asteroids, and discuss the potential of such observations.

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.

Dynamical evidence regarding the relationship between asteroids and meteorites

NASA Technical Reports Server (NTRS)

Wetherill, G. W.

1978-01-01

Meteorites are fragments of small solar system bodies transferring into the vicinity of earth from the inner edge of the asteroid belt. Photometric measurements support an association between Apollo objects and chondritic meteorites. Dynamical arguments indicate that most Apollo objects are devolatilized comet residues, however; petrographic and cosmogonical reasons argue against this conclusion.

The importance of exploring the asteroid belt.

PubMed

Papagiannis, M D

1983-01-01

Following life's innate tendency to expand into every available space, technological civilizations will inevitably colonize the entire galaxy establishing space habitats around all its well-behaved stars. The most reasonable place in our solar system to test this possibility is the asteroid belt, which is an ideal source of raw materials for space colonies.

CubeSat Mission- Near-Earth Asteroid Scout (animation only, no audio)

NASA Image and Video Library

2016-09-21

The Near-Earth Asteroid Scout, or NEA Scout, is a robotic reconnaissance mission that will deploy a 6U CubeSat to fly by and return data from an asteroid representative of possible human destinations. Using a solar sail for its propulsion system, it will perform reconnaissance of an asteroid, take pictures and observe its position in space. Launching on NASA's Space Launch System rocket, the CubeSat deployment animation starts at the 1:25 timecode with the solar sail deployment animation beginning at the 2:54 timecode. The NEA Scout team is currently evaluating a range of targets, and is continually updating the candidate pool based on new discoveries and expected performance. NEA Scout is one of three payloads selected by NASA’s Human Exploration and Operations Mission Directorate. These small satellites were chosen to address Strategic Knowledge Gaps (SKGs) and help inform research strategies and prioritize technology development for future human and robotic exploration. It is being developed at NASA’s Marshall Space Flight Center in Huntsville, Alabama. Learn more by visiting http://www.nasa.gov/content/nea-scout

Spacewatch discovery of near-Earth asteroids

NASA Technical Reports Server (NTRS)

Gehrels, Tom

1992-01-01

Our overall scientific goal is to survey the solar system to completion - that is, to find the various populations and to study their statistics, interrelations, and origins. The practical benefit to SERC is that we are finding Earth-approaching asteroids that are accessible for mining. Our system can detect Earth-approachers in the 1-km size range even when they are far away, and can detect smaller objects when they are moving rapidly past Earth. Until Spacewatch, the size range of 6-300 meters in diameter for the near-Earth asteroids was unexplored. This important region represents the transition between the meteorites and the larger observed near-Earth asteroids. One of our Spacewatch discoveries, 1991 VG, may be representative of a new orbital class of object. If it is really a natural object, and not man-made, its orbital parameters are closer to those of the Earth than we have seen before; its delta V is the lowest of all objects known thus far. We may expect new discoveries as we continue our surveying, with fine-tuning of the techniques.

The Ion Propulsion System for the Asteroid Redirect Robotic Mission

NASA Technical Reports Server (NTRS)

Herman, Daniel A.; Santiago, Walter; Kamhawi, Hani; Polk, James E.; Snyder, John Steven; Hofer, Richard; Sekerak, Michael

2016-01-01

The Asteroid Redirect Robotic Mission is a Solar Electric Propulsion Technology Demonstration Mission (ARRM) whose main objectives are to develop and demonstrate a high-power solar electric propulsion capability for the Agency and return an asteroidal mass for rendezvous and characterization in a companion human-crewed mission. This high-power solar electric propulsion capability, or an extensible derivative of it, has been identified as a critical part of NASA's future beyond-low-Earth-orbit, human-crewed exploration plans. This presentation presents the conceptual design of the ARRM ion propulsion system, the status of the NASA in-house thruster and power processing development activities, the status of the planned technology maturation for the mission through flight hardware delivery, and the status of the mission formulation and spacecraft acquisition.

Use of outer planet satellites and asteroids as sources of raw materials for life support systems

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

Molton, P.M.; Divine, T.E.

1977-01-01

Industrialization of space and other space activities depend entirely on supply of materials from the Earth. This is a high cost route for materials supply. Space industrialization will require life support systems for maintenance and operation staff and these will of necessity be of a sophisticated nature. Use of raw materials obtained by an unmanned space shuttle, initially, and by manned shuttles later could significantly reduce the cost of life support in space. These raw materials could be obtained from small asteroids and satellites, and would consist of primary nutrients. Future development of such sources is discussed, including food productionmore » in automated asteroid-based facilities. The level of technology required is available now, and should become economical within a century.« less

Short-term capture of the Earth-Moon system

NASA Astrophysics Data System (ADS)

Qi, Yi; de Ruiter, Anton

2018-06-01

In this paper, the short-term capture (STC) of an asteroid in the Earth-Moon system is proposed and investigated. First, the space condition of STC is analysed and five subsets of the feasible region are defined and discussed. Then, the time condition of STC is studied by parameter scanning in the Sun-Earth-Moon-asteroid restricted four-body problem. Numerical results indicate that there is a clear association between the distributions of the time probability of STC and the five subsets. Next, the influence of the Jacobi constant on STC is examined using the space and time probabilities of STC. Combining the space and time probabilities of STC, we propose a STC index to evaluate the probability of STC comprehensively. Finally, three potential STC asteroids are found and analysed.

Erosive Hit-and-Run Impact Events: Debris Unbound

NASA Astrophysics Data System (ADS)

Sarid, Gal; Stewart, Sarah T.; Leinhardt, Zoë M.

2016-01-01

Erosive collisions among planetary embryos in the inner solar system can lead to multiple remnant bodies, varied in mass, composition and residual velocity. Some of the smaller, unbound debris may become available to seed the main asteroid belt. The makeup of these collisionally produced bodies is different from the canonical chondritic composition, in terms of rock/iron ratio and may contain further shock-processed material. Having some of the material in the asteroid belt owe its origin from collisions of larger planetary bodies may help in explaining some of the diversity and oddities in composition of different asteroid groups.

Sediment-dispersed extraterrestrial chromite traces a major asteroid disruption event.

PubMed

Schmitz, Birger; Häggström, Therese; Tassinari, Mario

2003-05-09

Abundant extraterrestrial chromite grains from decomposed meteorites occur in middle Ordovician (480 million years ago) marine limestone over an area of approximately 250,000 square kilometers in southern Sweden. The chromite anomaly gives support for an increase of two orders of magnitude in the influx of meteorites to Earth during the mid-Ordovician, as previously indicated by fossil meteorites. Extraterrestrial chromite grains in mid-Ordovician limestone can be used to constrain in detail the temporal variations in flux of extraterrestrial matter after one of the largest asteroid disruption events in the asteroid belt in late solar-system history.

Linear stability of collinear equilibrium points around an asteroid as a two-connected-mass: Application to fast rotating Asteroid 2000EB 14

NASA Astrophysics Data System (ADS)

Hirabayashi, Masatoshi; Morimoto, Mutsuko Y.; Yano, Hajime; Kawaguchi, Jun'ichiro; Bellerose, Julie

2010-04-01

This note discusses the stability of collinear equilibrium points around a rotating system composed of two masses rigidly connected by a massless rod in the case, where the centripetal force outweighs the gravitational force. It is found that a stable region appears at L1 when the ratio of gravitational to centripetal acceleration is less than 0.125, and that there is always no stable area at L2 and L3; the result is applied to the fast rotating Asteroid 2000EB 14.

Natural and Artificial Satellite Dynamics and Evolution around Near-Earth Asteroids with Solar Radiation Pressure

NASA Astrophysics Data System (ADS)

Rieger, Samantha M.

Natural and artificial satellites are subject to perturbations when orbiting near-Earth asteroids. These perturbations include non-uniform gravity from the asteroid, third-body disturbances from the Sun, and solar radiation pressure. For small natural (1 cm-15 m) and artificial satellites, solar radiation pressure is the primary perturbation that will cause their orbits to go unstable. For the asteroid Bennu, the future target of the spacecraft OSIRIS-REx, the possibility of natural satellites having stable orbits around the asteroid and characterize these stable regions is investigated. It has been found that the main orbital phenomena responsible for the stability or instability of these possible natural satellites are Sun-synchronous orbits, the modified Laplace plane, and the Kozai resonance. These findings are applied to other asteroids as well as to artificial satellites. The re-emission of solar radiation pressure through BYORP is also investigated for binary asteroid systems. Specifically, the BYORP force is combined with the Laplace plane such that BYORP expands the orbit of the binary system along the Laplace surface where the secondary increases in inclination. For obliquities from 68.875° - 111.125° the binary will eventually extend into the Laplace instability region, where the eccentricity of the orbit will increase. A subset of the instability region leads to eccentricities high enough that the secondary will impact the primary. This result inspired the development of a hypothesis of a contact-binary binary cycle described briefly in the following. YORP will increase the spin rate of a contact binary while also driving the spin-pole to an obliquity of 90°. Eventually, the contact binary will fission. The binary will subsequently become double-synchronous, thus allowing the BYORP acceleration to have secular effects on the orbit. The orbit will then expand along the Laplace surface to the Laplace plane instability region eventually leading to an impact and the start of a new cycle with the YORP process.

Rendezvous and Docking Strategy for Crewed Segment of the Asteroid Redirect Mission

NASA Technical Reports Server (NTRS)

Hinkel, Heather D.; Cryan, Scott P.; D'Souza, Christopher; Dannemiller, David P.; Brazzel, Jack P.; Condon, Gerald L.; Othon, William L.; Williams, Jacob

2014-01-01

This paper will describe the overall rendezvous, proximity operations and docking (RPOD) strategy in support of the Asteroid Redirect Crewed Mission (ARCM), as part of the Asteroid Redirect Mission (ARM). The focus of the paper is on the crewed mission phase of ARM, starting with the establishment of Orion in the Distant Retrograde Orbit (DRO) and ending with docking to the Asteroid Redirect Vechicle (ARV). The paper will detail the sequence of maneuvers required to execute the rendezvous and proximity operations mission phases along with the on-board navigation strategies, including the final approach phase. The trajectories to be considered will include target vehicles in a DRO. The paper will also discuss the sensor requirements for rendezvous and docking and the various trade studies associated with the final sensor selection. Building on the sensor requirements and trade studies, the paper will include a candidate sensor concept of operations, which will drive the selection of the sensor suite; concurrently, it will be driven by higher level requirements on the system, such as crew timeline constraints and vehicle consummables. This paper will address how many of the seemingly competing requirements will have to be addressed to create a complete system and system design. The objective is to determine a sensor suite and trajectories that enable Orion to successfully rendezvous and dock with a target vehicle in trans lunar space. Finally, the paper will report on the status of a NASA action to look for synergy within RPOD, across the crewed and robotic asteroid missions.

Probing the Solar System with LSST

NASA Astrophysics Data System (ADS)

Harris, A.; Ivezic, Z.; Juric, M.; Lupton, R.; Connolly, A.; Kubica, J.; Moore, A.; Bowell, E.; Bernstein, G.; Cook, K.; Stubbs, C.

2005-12-01

LSST will catalog small Potentially Hazardous Asteroids (PHAs), survey the main belt asteroid (MBA) population to extraordinarily small size, discover comets far from the sun where their nuclear properties can be discerned without coma, and survey the Centaur and Trans-Neptunian Object (TNO) populations. The present planned observing strategy is to ``visit'' each field (9.6 deg2) with two back-to-back exposures of ˜ 15 sec, reaching to at least V magnitude 24.5. An intra-night revisit time of the order half an hour will distinguish stationary transients from even very distant ( ˜ 70 AU) solar system bodies. In order to link observations and determine orbits, each sky area will be visited several times during a month, spaced by about a week. This cadence will result in orbital parameters for several million MBAs and about 20,000 TNOs, with light curves and colorimetry for the brighter 10% or so of each population. Compared to the current data available, this would represent factor of 10 to 100 increase in the numbers of orbits, colors, and variability of the two classes of objects. The LSST MBA and TNO samples will enable detailed studies of the dynamical and chemical history of the solar system. The increase in data volume associated with LSST asteroid science will present many computational challenges to how we might extract tracks and orbits of asteroids from the underlying clutter. Tree-based algorithms for multihypothesis testing of asteroid tracks can help solve these challenges by providing the necessary 1000-fold speed-ups over current approaches while recovering 95% of the underlying moving objects.

Habitation Concepts and Tools for Asteroid Missions and Commercial Applications

NASA Technical Reports Server (NTRS)

Smitherman, David

2010-01-01

In 2009 studies were initiated in response to the Augustine Commission s review of the Human Spaceflight Program to examine the feasibility of additional options for space exploration beyond the lunar missions planned in the Constellation Program. One approach called a Flexible Path option included possible human missions to near-Earth asteroids. This paper presents an overview of possible asteroid missions with emphasis on the habitation options and vehicle configurations conceived for the crew excursion vehicles. One launch vehicle concept investigated for the Flexible Path option was to use a dual launch architecture that could serve a wide variety of exploration goals. The dual launch concept used two medium sized heavy lift launch vehicles for lunar missions as opposed to the single Saturn V architecture used for the Apollo Program, or the one-and-a-half vehicle Ares I / Ares V architecture proposed for the Constellation Program. This dual launch approach was studied as a Flexible Path option for lunar missions and for possible excursions to other destinations like geosynchronous earth orbiting satellites, Lagrange points, and as presented in this paper, asteroid rendezvous. New habitation and exploration systems for the crew are presented that permit crew sizes from 2 to 4, and mission durations from 100 to 360 days. Vehicle configurations are presented that include habitation systems and tools derived from International Space Station (ISS) experience and new extra-vehicular activity tools for asteroid exploration, Figure 1. Findings from these studies and as presented in this paper indicate that missions to near-Earth asteroids appear feasible in the near future using the dual launch architecture, the technologies under development from the Constellation Program, and systems derived from the current ISS Program. In addition, the capabilities derived from this approach that are particularly beneficial to the commercial sector include human access to geosynchronous orbit and the Lagrange points with new tools for satellite servicing and in-space assembly.

Silicate Phases on the Surfaces of Trojan Asteroids

NASA Astrophysics Data System (ADS)

Martin, Audrey; Emery, Joshua P.; Lindsay, Sean S.

2017-10-01

Determining the origin of asteroids provides an effective means of constraining the solar system’s dynamic past. Jupiter Trojan asteroids (hereafter Trojans) may help in determining the amount of radial mixing that occurred during giant planet migration. Previous studies aimed at characterizing surface composition show that Trojans have low albedo surfaces and are spectrally featureless in the near infrared. The thermal infrared (TIR) wavelength range has advantages for detecting silicates on low albedo asteroids such as Trojans. The 10 μm region exhibits strong features due to the Si-O fundamental molecular vibrations. Silicates that formed in the inner solar system likely underwent thermal annealing, and thus are crystalline, whereas silicates that accreted in the outer solar system experienced less thermal processing, and therefore are more likely to have remained in an amorphous phase. We hypothesize that the Trojans formed in the outer solar system (i.e., the Kuiper Belt), and therefore will have a more dominant amorphous spectral silicate component. With TIR spectra from the Spitzer Space Telescope, we identify mineralogical features from the surface of 11 Trojan asteroids. Fine-grain mixtures of crystalline pyroxene and olivine exhibit a 10 μm feature with sharp cutoffs between about 9 μm and 12 μm, which create a broad flat plateau. Amorphous phases, when present, smooth the sharp emission features, resulting in a dome-like shape. Preliminary results indicate that the surfaces of analyzed Trojans contain primarily amorphous silicates. Emissivity spectra of asteroids 1986 WD and 4709 Ennomos include small peaks in the 10 μm region, diagnostic of small amounts of crystalline olivine. One explanation is that Trojans formed in the same region as Kuiper Belt objects, and when giant planet migration ensued, they were swept into Jupiter’s stable Lagrange points where they are found today. As such, it is possible that an ancestral group of Kuiper Belt objects were separated from Trojans during large planet migration.

More chips off of Asteroid (4) Vesta: Characterization of eight Vestoids and their HED meteorite analogs

NASA Astrophysics Data System (ADS)

Hardersen, Paul S.; Reddy, Vishnu; Roberts, Rachel; Mainzer, Amy

2014-11-01

Vestoids are generally considered to be fragments from Asteroid (4) Vesta that were ejected by past collisions that document Vesta's collisional history. Dynamical Vestoids are defined by their spatial proximity with Vesta (Zappala, V., Bendjoya, Ph., Cellino, A., Farinella, P., Froeschle', C. [1995]. Icarus 116, 291-314; Nesvorny, D. [2012]. Nesvorny HCM Asteroid Families V2.0. EAR-A-VARGBDET-5-NESVORNYFAM-V2.0. NASA Planetary Data System.). Taxonomic Vestoids are defined as V-type asteroids that have a photometric, visible-wavelength spectral, or other observational relationship with Vesta (Tholen, D.J., 1984. Asteroid Taxonomy from Cluster Analysis of Photometry. Ph.D. Thesis, University of Arizona, Tucson; Bus, S.J., Binzel, R.P. [2002]. Icarus 158, 106-145; Carvano, J., Hasselmann, P.H., Lazzaro, D., Mothe'-Diniz, T. [2010]. Astron. Astrophys. 510, A43). We define 'genetic Vestoids' as V-type asteroids that are probable fragments ejected from (4) Vesta based on the supporting combination of dynamical, near-infrared (NIR) spectral, and taxonomic evidence. NIR reflectance spectroscopy is one of the primary ground-based techniques to constrain an asteroid's major surface mineralogy (Burns, R.G. [1993a]. Mineralogical Applications of Crystal Field Theory. Cambridge University Press, Cambridge, UK, 551 p). Despite the reasonable likelihood that many dynamical and taxonomic Vestoids likely originate from Vesta, ambiguity exists concerning the fraction of these populations that are from Vesta as compared to the fraction of asteroids that might not be related to Vesta. Currently, one of the most robust techniques to identify the genetic Vestoid population is through NIR reflectance spectroscopy from ∼0.7 to 2.5 μm. The derivation of spectral band parameters, and the comparison of those band parameters with those from representative samples from the Howardite-Eucrite-Diogenite (HED) meteorite types, allows a direct comparison of their primary mineralogies. Establishing tighter constraints on the genetic Vestoid population will better inform mass estimates for the current population of probable Vestoids, will provide more accurate orbital information of Vestoid migration through time that will assist dynamical models, and will constrain the overall current abundance of basaltic material in the main asteroid belt (Moskovitz, N.A., Jedicke, R., Gaidos, E., Willman, M., Nesvorny, D., Fevig, R. [2008]. Icarus 198, 77-90). This work reports high-quality NIR spectra, and their respective interpretations, for eight Vp-type asteroids, as defined by Carvano et al. (Carvano, J., Hasselmann, P.H., Lazzaro, D., Mothe'-Diniz, T. [2010]. Astron. Astrophys. 510, A43), that were observed at the NASA Infrared Telescope Facility on January 14, 2013 UT. They include: (3867) Shiretoko, (5235) Jean-Loup, (5560) Amytis, (6331) 1992 FZ1, (6976) Kanatsu, (17469) 1991 BT, (29796) 1999 CW77, and (30872) 1992 EM17. All eight asteroids exhibit the broad ∼0.9- and ∼1.9-μm mineral absorption features indicative of pyroxene on each asteroid's surface. Data reduction and analysis via multiple techniques produced consistent results for the derived spectral absorption band centers and average pyroxene surface chemistries for all eight asteroids (Reddy, V., Sanchez, J.A., Nathues, A., Moskovitz, N.A., Li, J.-Y, Cloutis, E.A., Archer, K., Tucker, R.A., Gaffey, M.J., Mann, P.J., Sierks, H., Schade, U. [2012c]. Icarus 217, 153-168; Lindsay, S.S., Emery, J.P., Marchis, F., Enriquez, J., Assafin, M. [2013]. A spectroscopic and mineralogic study of multiple asteroid systems. American Astronomical Society, DPS Meeting #45, #112.04; Lindsay, S.S., Marchis, F., Emery, J.P., Enriquez, J.E., Assafin, M. [2014]. Icarus, submitted for publication; Gaffey, M.J., Cloutis, E.A., Kelley, M.K., Reed, K.L. [2002]. Mineralogy of asteroids. In: Bottke Jr., W.F., Cellino, A., Paolicchi, P., Binzel, R.P. (Eds.), Asteroids III. The University of Arizona Press, Tucson, pp. 183-204; Burbine, T.H., Buchanan, P.C., Dolkar, T., Binzel, R.P. [2009]. Met. Planet. Sci. 44, 1331-1341.). (3867) Shiretoko is most consistent with the eucrite meteorites while the remaining seven asteroids are most consistent with the howardite meteorites. The existing evidence suggests that all eight of these Vp-type asteroids are genetic Vestoids that probably originated from Vesta's surface.

Modeling Momentum Transfer from Kinetic Impacts: Implications for Redirecting Asteroids

DOE PAGES

Stickle, A. M.; Atchison, J. A.; Barnouin, O. S.; ...

2015-05-19

Kinetic impactors are one way to deflect a potentially hazardous object headed for Earth. The Asteroid Impact and Deflection Assessment (AIDA) mission is designed to test the effectiveness of this approach and is a joint effort between NASA and ESA. The NASA-led portion is the Double Asteroid Redirect Test (DART) and is composed of a ~300-kg spacecraft designed to impact the moon of the binary system 65803 Didymos. The deflection of the moon will be measured by the ESA-led Asteroid Impact Mission (AIM) (which will characterize the moon) and from ground-based observations. Because the material properties and internal structure ofmore » the target are poorly constrained, however, analytical models and numerical simulations must be used to understand the range of potential outcomes. Here, we describe a modeling effort combining analytical models and CTH simulations to determine possible outcomes of the DART impact. We examine a wide parameter space and provide predictions for crater size, ejecta mass, and momentum transfer following the impact into the moon of the Didymos system. For impacts into “realistic” asteroid types, these models produce craters with diameters on the order of 10 m, an imparted Δv of 0.5–2 mm/s and a momentum enhancement of 1.07 to 5 for a highly porous aggregate to a fully dense rock.« less

Asteroid Sample Return Mission Launches on This Week @NASA – September 9, 2016

NASA Image and Video Library

2016-09-09

On Sept. 8, NASA launched the Origins, Spectral Interpretation, Resource Identification, Security - Regolith Explorer, or OSIRIS-REx mission from Cape Canaveral Air Force Station in Florida. OSIRIS-REx, the first U.S. mission to sample an asteroid, is scheduled to arrive at near-Earth asteroid Bennu in 2018. Mission plans call for the spacecraft to survey the asteroid, retrieve a small sample from its surface, and return the sample to Earth for study in 2023. Analysis of that sample is expected to reveal clues about the history of Bennu over the past 4.5 billion years, as well as clues about the evolution of our solar system. Also, Jeff Williams’ Record-Breaking Spaceflight Concludes, Next ISS Crew Prepares for Launch, Sample Return Robot Challenge, NASA X-Plane Gets its Wing, and Convergent Aeronautics Solutions Showcase!

Analysis of GSC 2475-1587 and GSC 841-277: Two Eclipsing Binary Stars Found During Asteroid Lightcurve Observations

NASA Astrophysics Data System (ADS)

Stephens, R. D.; Warner, B. D.

2006-05-01

When observing asteroids we select from two to five comparison stars for differential photometry, taking the average value of the comparisons for the single value to be subtracted from the value for the asteroid. As a check, the raw data of each comparison star are plotted as is the difference between any single comparison and the average of the remaining stars in the set. On more than one occasion, we have found that at least one of the comparisons was variable. In two instances, we took time away from our asteroid lightcurve work to determine the period of the two binaries and attempted to model the system using David Bradstreet's Binary Maker 3. Unfortunately, neither binary showed a total eclipse. Therefore, our results are not conclusive and present only one of many possibilities.

THE ASTEROID BELT AS A RELIC FROM A CHAOTIC EARLY SOLAR SYSTEM

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

Izidoro, André; Raymond, Sean N.; Pierens, Arnaud

The orbital structure of the asteroid belt holds a record of the solar system’s dynamical history. The current belt only contains ∼10{sup −3} Earth masses yet the asteroids’ orbits are dynamically excited, with a large spread in eccentricity and inclination. In the context of models of terrestrial planet formation, the belt may have been excited by Jupiter’s orbital migration. The terrestrial planets can also be reproduced without invoking a migrating Jupiter; however, as it requires a severe mass deficit beyond Earth’s orbit, this model systematically under-excites the asteroid belt. Here we show that the orbits of the asteroids may havemore » been excited to their current state if Jupiter’s and Saturn’s early orbits were chaotic. Stochastic variations in the gas giants’ orbits cause resonances to continually jump across the main belt and excite the asteroids’ orbits on a timescale of tens of millions of years. While hydrodynamical simulations show that the gas giants were likely in mean motion resonance at the end of the gaseous disk phase, small perturbations could have driven them into a chaotic but stable state. The gas giants’ current orbits were achieved later, during an instability in the outer solar system. Although it is well known that the present-day solar system exhibits chaotic behavior, our results suggest that the early solar system may also have been chaotic.« less

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).

ANTS: A New Concept for Very Remote Exploration with Intelligent Software Agents

NASA Astrophysics Data System (ADS)

Clark, P. E.; Curtis, S.; Rilee, M.; Truszkowski, W.; Iyengar, J.; Crawford, H.

2001-12-01

ANTS (Autonomous Nano-Technology Swarm), a NASA advanced mission concept, is a large (100 to 1000 member) swarm of pico-class (1 kg) totally autonomous spacecraft that prospect the asteroid belt. As the capacity and complexity of hardware and software, and the sophistication of technical and scientific goals have increased, greater cost constraints have led to fewer resources and thus, the need to operate spacecraft with less frequent contact. At present, autonomous operation of spacecraft systems allows great capability of spacecraft to 'safe' themselves when conditions threaten spacecraft safety. To further develop spacecraft capability, NASA is at the forefront of Intelligent Software Agent (ISA) research, performing experiments in space and on the ground to advance deliberative and collaborative autonomous control techniques. Selected missions in current planning stages require small groups of spacecraft to cooperate at a tactical level to select and schedule measurements to be made by appropriate instruments to characterize rapidly unfolding real-time events on a routine basis. The next level of development, which we are considering here, is in the use of ISAs at a strategic level, to explore the final, remote frontiers of the solar system, potentially involving a large class of objects with only infrequent contact possible. Obvious mission candidates are mainbelt asteroids, a population consisting of more than a million small bodies. Although a large fraction of solar system objects are asteroids, little data is available for them because the vast majority of them are too small to be observed except in close proximity. Asteroids originated in the transitional region between the inner (rocky) and outer (solidified gases) solar system, have remained largely unmodified since formation, and thus have a more primitive composition which includes higher abundances of siderophile (metallic iron-associated) elements and volatiles than other planetary surfaces. As a result, there has been interest in asteroids as sources of exploitable resources. Far more reconnaissance is required before such a program is undertaken. A traditional mission approach (to explore larger asteroids sequentially) is not adequate for determining the systematic distribution of exploitable material in the asteroid population. Our approach involves the use of distributed intelligence in a swarm of tiny spacecraft, each with specialized instrument capability (e.g., advanced computing, imaging, spectrometry, etc.) to evaluate the resource potential of the entire population. Supervised clusters of spacecraft will operate simultaneously within a broadly defined framework of goals to select targets (>1000) from among available candidates and to develop scenarios for studying targets simultaneously. Spacecraft use solar sails to fly directly to asteroids 1 kilometer or greater in diameter. Selected swarm members return to Earth with data, replacements join the swarm as needed. We would like to acknowledge our students R. Watson, V. Cox, and F. Olukomo for their support of this work.

Performance Characterization of a Landmark Measurement System for ARRM Terrain Relative Navigation

NASA Technical Reports Server (NTRS)

Shoemaker, Michael A.; Wright, Cinnamon; Liounis, Andrew J.; Getzandanner, Kenneth M.; Van Eepoel, John M.; DeWeese, Keith D.

2016-01-01

This paper describes the landmark measurement system being developed for terrain relative navigation on NASAs Asteroid Redirect Robotic Mission (ARRM),and the results of a performance characterization study given realistic navigational and model errors. The system is called Retina, and is derived from the stereo-photoclinometry methods widely used on other small-body missions. The system is simulated using synthetic imagery of the asteroid surface and discussion is given on various algorithmic design choices. Unlike other missions, ARRMs Retina is the first planned autonomous use of these methods during the close-proximity and descent phase of the mission.

Performance Characterization of a Landmark Measurement System for ARRM Terrain Relative Navigation

NASA Technical Reports Server (NTRS)

Shoemaker, Michael; Wright, Cinnamon; Liounis, Andrew; Getzandanner, Kenneth; Van Eepoel, John; Deweese, Keith

2016-01-01

This paper describes the landmark measurement system being developed for terrain relative navigation on NASAs Asteroid Redirect Robotic Mission (ARRM),and the results of a performance characterization study given realistic navigational and model errors. The system is called Retina, and is derived from the stereophotoclinometry methods widely used on other small-body missions. The system is simulated using synthetic imagery of the asteroid surface and discussion is given on various algorithmic design choices. Unlike other missions, ARRMs Retina is the first planned autonomous use of these methods during the close-proximity and descent phase of the mission.

Orbital Analysis of Two Triple Systems in the Open Cluster NGC 2516

NASA Astrophysics Data System (ADS)

Veramendi, M. E.; González, J. F.

2010-12-01

We report the discovery of two hierarchical triple systems in the open cluster NGC 2516. Both systems are double-lined spectroscopic binaries whose center-of-mass velocity varies in a time scale of a few years. The system BDA 19 consists of an eccentric spectroscopic binary with a period of 8.7 days and a third body orbiting with a period of about 3300 days. The close pair in the triple BDA 2 has an orbital period of 11.2 days and contains a HgMn star.

Earth's Minimoons: Opportunities for Science and Technology.

NASA Astrophysics Data System (ADS)

Jedicke, Robert; Bolin, Bryce T.; Bottke, William F.; Chyba, Monique; Fedorets, Grigori; Granvik, Mikael; Jones, Lynne; Urrutxua, Hodei

2018-05-01

Twelve years ago the Catalina Sky Survey discovered Earth's first known natural geocentric object other than the Moon, a few-meter diameter asteroid designated \\RH. Despite significant improvements in ground-based asteroid surveying technology in the past decade they have not discovered another temporarily-captured orbiter (TCO; colloquially known as minimoons) but the all-sky fireball system operated in the Czech Republic as part of the European Fireball Network detected a bright natural meteor that was almost certainly in a geocentric orbit before it struck Earth's atmosphere. Within a few years the Large Synoptic Survey Telescope (LSST) will either begin to regularly detect TCOs or force a re-analysis of the creation and dynamical evolution of small asteroids in the inner solar system. The first studies of the provenance, properties, and dynamics of Earth's minimoons suggested that there should be a steady state population with about one 1- to 2-meter diameter captured objects at any time, with the number of captured meteoroids increasing exponentially for smaller sizes. That model was then improved and extended to include the population of temporarily-captured flybys (TCFs), objects that fail to make an entire revolution around Earth while energetically bound to the Earth-Moon system. Several different techniques for discovering TCOs have been considered but their small diameters, proximity, and rapid motion make them challenging targets for existing ground-based optical, meteor, and radar surveys. However, the LSST's tremendous light gathering power and short exposure times could allow it to detect and discover many minimoons. We expect that if the TCO population is confirmed, and new objects are frequently discovered, they can provide new opportunities for 1) studying the dynamics of the Earth-Moon system, 2) testing models of the production and dynamical evolution of small asteroids from the asteroid belt, 3) rapid and frequent low delta-v missions to multiple minimoons, and 4) evaluating in-situ resource utilization techniques on asteroidal material. Here we review the past decade of minimoon studies in preparation for capitalizing on the scientific and commercial opportunities of TCOs in the first decade of LSST operations.

Planetary Nebulae that Cannot Be Explained by Binary Systems

NASA Astrophysics Data System (ADS)

Bear, Ealeal; Soker, Noam

2017-03-01

We examine the images of hundreds of planetary nebulae (PNe) and find that for about one in six PNe the morphology is too “messy” to be accounted for by models of stellar binary interaction. We speculate that interacting triple stellar systems shaped these PNe. In this preliminary study, we qualitatively classify PNe by one of four categories. (1) PNe that show no need for a tertiary star to account for their morphology. (2) PNe whose structure possesses a pronounced departure from axial-symmetry and/or mirror-symmetry. We classify these, according to our speculation, as “having a triple stellar progenitor.” (3) PNe whose morphology possesses departure from axial-symmetry and/or mirror-symmetry, but not as pronounced as in the previous class, and are classified as “likely shaped by triple stellar system.” (4) PNe with minor departure from axial-symmetry and/or mirror-symmetry that could have been also caused by an eccentric binary system or the interstellar medium. These are classified as “maybe shaped by a triple stellar system.” Given a weight η t = 1, η l = 0.67, and η m = 0.33 to classes 2, 3, and 4, respectively, we find that according to our assumption about 13%-21% of PNe have been shaped by triple stellar systems. Although in some evolutionary scenarios not all three stars survive the evolution, we encourage the search for a triple stellar systems at the center of some PNe.

Compensator-based 6-DOF control for probe asteroid-orbital-frame hovering with actuator limitations

NASA Astrophysics Data System (ADS)

Liu, Xiaosong; Zhang, Peng; Liu, Keping; Li, Yuanchun

2016-05-01

This paper is concerned with 6-DOF control of a probe hovering in the orbital frame of an asteroid. Considering the requirements of the scientific instruments pointing direction and orbital position in practical missions, the coordinate control of relative attitude and orbit between the probe and target asteroid is imperative. A 6-DOF dynamic equation describing the relative translational and rotational motion of a probe in the asteroid's orbital frame is derived, taking the irregular gravitation, model and parameter uncertainties and external disturbances into account. An adaptive sliding mode controller is employed to guarantee the convergence of the state error, where the adaptation law is used to estimate the unknown upper bound of system uncertainty. Then the controller is improved to deal with the practical problem of actuator limitations by introducing a RBF neural network compensator, which is used to approximate the difference between the actual control with magnitude constraint and the designed nominal control law. The closed-loop system is proved to be asymptotically stable through the Lyapunov stability analysis. Numerical simulations are performed to compare the performances of the preceding designed control laws. Simulation results demonstrate the validity of the control scheme using the compensator-based adaptive sliding mode control law in the presence of actuator limitations, system uncertainty and external disturbance.

Asteroids in the High Cadence Transient Survey

NASA Astrophysics Data System (ADS)

Peña, J.; Fuentes, C.; Förster, F.; Maureira, J. C.; San Martín, J.; Littín, J.; Huijse, P.; Cabrera-Vives, G.; Estévez, P. A.; Galbany, L.; González-Gaitán, S.; Martínez, J.; de Jaeger, Th.; Hamuy, M.

2018-03-01

We report on the serendipitous observations of solar system objects imaged during the High cadence Transient Survey 2014 observation campaign. Data from this high-cadence wide-field survey was originally analyzed for finding variable static sources using machine learning to select the most-likely candidates. In this work, we search for moving transients consistent with solar system objects and derive their orbital parameters. We use a simple, custom motion detection algorithm to link trajectories and assume Keplerian motion to derive the asteroid’s orbital parameters. We use known asteroids from the Minor Planet Center database to assess the detection efficiency of the survey and our search algorithm. Trajectories have an average of nine detections spread over two days, and our fit yields typical errors of {σ }a∼ 0.07 {au}, σ e ∼ 0.07 and σ i ∼ 0.°5 in semimajor axis, eccentricity, and inclination, respectively, for known asteroids in our sample. We extract 7700 orbits from our trajectories, identifying 19 near-Earth objects, 6687 asteroids, 14 Centaurs, and 15 trans-Neptunian objects. This highlights the complementarity of supernova wide-field surveys for solar system research and the significance of machine learning to clean data of false detections. It is a good example of the data-driven science that Large Synoptic Survey Telescope will deliver.

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.

The Space Launch System and the Proving Ground: Pathways to Mars

NASA Astrophysics Data System (ADS)

Klaus, K.

2014-12-01

Introduction: The Space Launch System (SLS) is the most powerful rocket ever built and provides a critical heavy-lift launch capability. We present mission concepts relevant to NASA's Cislunar Proving Ground and the Global Exploration Roadmap (GER).Asteroid Redirect Mission (ARM): ARM in part is a mission to the lunar vicinity. The ARM mission requirements result in system design based on a modified version of our 702 spacecraft. Including a NASA Docking System (NDS) on the Asteroid Redirect Vehicle allows for easier crewed exploration integration and execution. Exploration Augmentation Module (EAM): Crew operations at a redirected asteroid could be significantly enhanced by providing additional systems and EVA capabilities beyond those available from the Orion only. An EAM located with the asteroid would improve the science and technical return of the asteroid mission while also increasing Orion capability through resource provision and providing an abort location and safe haven for contingencies. The EAM could be repurposed as a cislunar exploration platform that advances scientific research, enables lunar surface exploration and provides a deep space vehicle assembly and servicing site. International Space Station (ISS) industry partners have been working for the past several years on concepts for using ISS development methods and assets to support a broad range of missions. These concepts have matured along with planning details for NASA's SLS and Orion for a platform located in the Earth-Moon Libration (EML) system or Distant Retrograde Orbit (DRO).Lunar Surface: The mission objectives are to provide lunar surface access for crew and cargo and to provide as much reuse as possible. Subsequent missions to the surface can reuse the same lander and Lunar Transfer Vehicle.Mars Vicinity: The International space community has declared that our unified horizon goal is for a human mission to Mars. Translunar infrastructure and heavy lift capability are key to this approach. The moons of Mars would provide an excellent stepping stone to the surface. As a "shake-down" cruise before landing, a mission to Deimos or Phobos would test all of the systems except those needed to get to the surface and back. This test would provide confidence for the in-space transportations and crew habitat systems.

Granular media in the context of small bodies

NASA Astrophysics Data System (ADS)

Tancredi, G.

2014-07-01

Granular materials of different particle sizes are present on the surface and the interior of several atmosphereless Solar System bodies. The presence of very fine particles on the surface of the Moon, the so-called regolith, was confirmed by the Apollo astronauts. From the polarimetric observations and phase angle curves, it is possible to indirectly infer the presence of fine particles on the surfaces of asteroids and planetary satellites. More recently, the visit of spacecraft to several asteroids and comets has provided us with close pictures of the surface, where particles of a wide size range from cm to hundreds of meters have been directly observed. The presence of even finer particles on the visited bodies can also be inferred from image analysis. Solar System bodies smaller than a few hundred km may have a variety of internal structures: monolithic single bodies, objects with internal fractures, rubble piles maintained as a single object by self-gravity, etc. After the visit of the small asteroid Itokawa, it has been speculated that ''some small asteroids appear to be clumps of gravel glued by a very weak gravity field'' (Asphaug 2007). We still do not know the internal structure of these rubble piles and the size distribution of the interior constituents, but these clumps could have several million meter-sized boulders inside. There are several pieces of evidence that many asteroids are agglomerates of small components, like: - Rotation periods for small asteroids - Tidal disruption of asteroids and comets when they enter the Roche's limit of a massive object - The existence of crater chains like the ones observed in Ganymede - Low density estimates (< 2 gr/cm^3) for many asteroids like Mathilde It has been proposed that several typical processes of granular materials (such as: the size segregation of boulders on Itokawa, the displacement of boulders on Eros, the ejection of dust clouds after impacts) can explain some features observed on these bodies. We review the numerical and experimental studies on granular materials with relevance to the understanding of the physical processes on the interior and the surfaces of minor bodies of the Solar System. In particular, we compare the different codes in use to perform numerical simulations of the physical evolution of these objects. We highlight results of these simulations. Some groups have been involved in laboratory experiments on granular material trying to reproduce the conditions in space: vacuum and low gravity. We describe the experimental set-ups and some results of these experiments. Some open problems and future line of work in this field will be presented.

Investigating the binary nature of active asteroid 288P/300163

NASA Astrophysics Data System (ADS)

Agarwal, Jessica

2016-10-01

We propose to study the suspected binary nature of active asteroid 288P/300163. We aim to confirm or disprove the existence of a binary nucleus, and - if confirmed - to measure the mutual orbital period and orbit orientation of the compoents, and their sizes. We request 5 orbits of WFC3 imaging, spaced at intervals of 8-12 days. 288P belongs to the recently discovered group of active asteroids, and is particularly remarkable as HST images obtained during its last close approach to Earth in 2011 are consistent with a barely resolved binary system. If confirmed, 288P would be the first known active binary asteroid. For the first time, we would see two important consequences of rotational break-up in a single object: binary formation and dust ejection, highlighting the importance of the YORP-effect in re-shaping the asteroid belt. Confirming 288P as a binary would be a key step towards understanding the evolutionary processes underlying asteroid activity. In order to resolve the two components we need 288P at a geocentric distance comparable to or less than we had in 2011 December (1.85 AU). This condition will be fulfilled for the first time since 2011, between mid-July and mid-November of 2016. The next opportunity to carry out such observations will be in 2021.

SPH simulations of high-speed collisions

NASA Astrophysics Data System (ADS)

Rozehnal, Jakub; Broz, Miroslav

2016-10-01

Our work is devoted to a comparison of: i) asteroid-asteroid collisions occurring at lower velocities (about 5 km/s in the Main Belt), and ii) mutual collisions of asteroids and cometary nuclei usually occurring at significantly higher relative velocities (> 10 km/s).We focus on differences in the propagation of the shock wave, ejection of the fragments and possible differences in the resultingsize-frequency distributions of synthetic asteroid families. We also discuss scaling with respect to the "nominal" target diameter D = 100 km, projectile velocity 3-7 km/s, for which a number of simulations were done so far (Durda et al. 2007, Benavidez et al. 2012).In the latter case of asteroid-comet collisions, we simulate the impacts of brittle or pre-damaged impactors onto solid monolithic targets at high velocities, ranging from 10 to 15 km/s. The purpose of this numerical experiment is to better understand impact processes shaping the early Solar System, namely the primordial asteroid belt during during the (late) heavy bombardment (as a continuation of Broz et al. 2013).For all hydrodynamical simulations we use a smoothed-particle hydrodynamics method (SPH), namely the lagrangian SPH3D code (Benz & Asphaug 1994, 1995). The gravitational interactions between fragments (re-accumulation) is simulated with the Pkdgrav tree-code (Richardson et al. 2000).

Spectrophotometric Characterisation of the Trojan Asteroids (624) Hektor et (911) Agamemnon

NASA Astrophysics Data System (ADS)

Doressoundiram, A.; Bott, N.; Perna, D.

2016-12-01

We obtained spectrophotometric observations of (624) Hektor and (911) Agamemnon, two large Trojan asteroids in order to (1) better understand the composition of their surface by means of their visible and infrared spectra, and (2) eventually detect a possible weak cometary activity by means of their images in the visible. We had data at different rotational phases to probe surface variegations. We found that the visible and infrared spectra are very similar to each other. That indicates a relatively homogenous surface for the asteroids, but it does not exclude the presence of localized inhomogeneities. Computation of a high spectral slope confirmed their D-type asteroids classification. No aqueous alteration absorption band was found in the visible spectra of both studied Trojan asteroids. This can be interpreted in two differents ways: either no liquid water flowed on their surface, or the surface is covered with a crust that mask the presence of hydrated minerals. We use a radiative transfer model to investigate the surface composition of these icy and primitive outer solar system bodies. We suggest models composed of mixtures of organic compounds, minerals and lower limits for water ice. Lastly, the analysis of the images of both Trojan asteroids did not reveal any cometary activity.

Asteroid masses with Gaia from ground and space-based observations

NASA Astrophysics Data System (ADS)

Ivantsov, Anatoliy; Hestroffer, Daniel; Thuillot, William; Bancelin, David

2013-04-01

Determination of masses of large asteroids is one of the expected scientific outputs from the future Gaia astrometric space mission. With the exception of binary asteroids or fly-by with a space probe, the error in mass determination depends on the size of perturbation effect produced on the motion of small asteroids. Considering the 5 years nominal duration of the Gaia mission, there will be mutual close encounters between asteroids occurring either close to the beginning or to the end of the mission. So that the maximum of deflection angle pertained to the perturbation maxima will not be observed directly by Gaia. Since astrometric data of the perturbed body before and after the encounter are mandatory to derive a perturber mass, the precision of mass determinations based solely on the Gaia observations will deteriorate in such cases. The possible way out consists in acquiring ground-based observations of high astrometric precision in time either before or after the Gaia operations, as it was suggested in [1]. By adding such data, it is expected to increase the number of derived asteroids masses [2]. This paper updates earlier predictions of encounters of large asteroids with smaller ones, e.g. [3], in terms of newly discovered asteroids and available ground-based observations. The method used consists in the computation of the offsets in right ascension and declination between the unperturbed and perturbed solutions fitted to the available observations for each small (perturbed) asteroid. For the purpose of decreasing CPU time, a special filter was applied based on the solution of the two-body problem and systematical search for close encounters, e.g. less than 0.1 A.U., of all known asteroids with the large (perturber) ones. The obtained list of asteroids-candidates was used as the input file for the mentioned above accurate calculations. Such a procedure was used for a few asteroids in [2]. The maximum visible offset corresponds to the dates when the complementary ground-based observations will be useful. [1] Hestroffer, D., Thuillot, W., Mouret, S., Colas, F., Tanga, P., Mignard, F., Delbo, M., Carry, B.: Ground-based observations of solar system bodies in complement to Gaia, SF2A-2008: Proceedings of the Annual meeting of the French Society of Astronomy and Astrophysics, 30 June - 4 July 2008, Paris, France, 2008. [2] Mouret, S., Hestroffer, D., and Mignard, F.: Asteroid masses and Gaia, Astronomy and Astrophysics, Vol. 472, pp. 1017-1027, 2007. [3] Mouret, S.: Investigations on the dynamics of minor planets with GAIA: orbits, masses and fundamental physics, PhD thesis, Paris Observatory, 2007. [4] Hilton, J.L., Seidelmann, P.K., and Middour, J.: Prospects for determining asteroid masses, Astronomical Journal, Vol. 112, pp. 2319-2329, 1996.

A triple point in 3-level systems

NASA Astrophysics Data System (ADS)

Nahmad-Achar, E.; Cordero, S.; López-Peña, R.; Castaños, O.

2014-11-01

The energy spectrum of a 3-level atomic system in the Ξ-configuration is studied. This configuration presents a triple point independently of the number of atoms, which remains in the thermodynamic limit. This means that in a vicinity of this point any quantum fluctuation will drastically change the composition of the ground state of the system. We study the expectation values of the atomic population of each level, the number of photons, and the probability distribution of photons at the triple point.

The composition of the Eureka family of Martian Trojan asteroids

NASA Astrophysics Data System (ADS)

Borisov, Galin; Christou, Apostolos; Bagnulo, Stefano

2016-10-01

The so-called Martian Trojan asteroids orbit the Sun just inside the terrestrial planet region. They are thought to date from the earliest period of the solar system's history (Scholl et al, Icarus, 2005). Recently, Christou (Icarus, 2013) identified an orbital concentration of Trojans, named the "Eureka" cluster after its largest member, 5261 Eureka. This asteroid belongs to the rare olivine-rich A taxonomic class (Rivkin et al, Icarus, 2007; Lim et al, DPS/EPSC 2011). Unlike asteroids belonging to other taxonomies (e.g. C or S), no orbital concentrations or families of A-types are currently known to exist. These asteroids may represent samples of the building blocks that came together to form Mars and the other terrestrial planets but have since been destroyed by collisions (Sanchez et al, Icarus, 2014, and references therein).We have used the X-SHOOTER echelle spectrograph on the ESO VLT KUEYEN to obtain vis-NIR reflectance spectra of asteroids in the cluster and test their genetic relationship to Eureka. During the presentation we will show the spectra, compare them with available spectra for Eureka itself and discuss the implications for the origin of this cluster and for other olivine-dominated asteroids in the Main Belt.Based on observations made with ESO Telescopes at the La Silla-Paranal Observatory under programme ID 296.C-5030 (PI: A. Christou). Astronomical Research at Armagh Observatory is funded by the Northern Ireland Department of Culture, Arts and Leisure (DCAL).

Almahata Sitta and Brecciated Ureilites: Insights into the Heterogeneity of Asteroids and Implications for Sample Return

NASA Technical Reports Server (NTRS)

Ross, A. J.; Herrin, J. S.; Alexander, L.; Downes, H.; Smith, C. L.; Jenniskens, P.

2011-01-01

Analysis of samples returned to terrestrial laboratories enables more precise measurements and a wider range of techniques to be utilized than can be achieved with either remote sensing or rover instruments. Furthermore, returning samples to Earth allows them to be stored and re-examined with future technology. Following the success of the Hayabusa mission, returning samples from asteroids should be a high priority for understanding of early solar system evolution, planetary formation and differentiation. Meteorite falls provide us with materials and insight into asteroidal compositions. Almahata Sitta (AS) was the first meteorite fall from a tracked asteroid (2008 TC3) [1] providing a rare opportunity to compare direct geochemical observations with remote sensing data. Although AS is predominantly ureilitic, multiple chondritic fragments have been associated with this fall [2,3]. This is not unique, with chondritic fragments being found in many howardite samples (as described in a companion abstract [4]) and in brecciated ureilites, some of which are known to represent ureilitic regolith [5-7]. The heterogeneity of ureilite samples, which are thought to all originate from a single asteroidal ureilite parent body (UPB) [5], gives us information about both internal and external asteroidal variations. This has implications both for the planning of potential sample return missions and the interpretation of material returned to Earth. This abstract focuses on multiple fragments of two meteorites: Almahata Sitta (AS); and Dar al Gani (DaG) 1047 (a highly brecciated ureilite, likely representative of ureilite asteroidal regolith).

Revolutionizing Remote Exploration with ANTS

NASA Astrophysics Data System (ADS)

Clark, P. E.; Rilee, M. L.; Curtis, S.; Truszkowski, W.

2002-05-01

We are developing the Autonomous Nano-Technology Swarm (ANTS) architecture based on an insect colony analogue for the cost-effective, efficient, systematic survey of remote or inaccessible areas with multiple object targets, including planetary surface, marine, airborne, and space environments. The mission context is the exploration in the 2020s of the most compelling remaining targets in the solar system: main belt asteroids. Main belt asteroids harbor important clues to Solar System origins and evolution which are central to NASA's goals in Space Science. Asteroids are smaller than planets, but their number is far greater, and their combined surface area likely dwarfs the Earth's. An asteroid survey will dramatically increase our understanding of the local resources available for the Human Exploration and Development of Space. During the mission composition, shape, gravity, and orbit parameters could be returned to Earth for perhaps several thousand asteroids. A survey of this area will rival the great explorations that encircled this globe, opened up the New World, and laid the groundwork for the progress and challenges of the last centuries. The ANTS architecture for a main belt survey consists of a swarm of as many as a thousand or more highly specialized pico-spacecraft that form teams to survey as many as one hundred asteroids a month. Multi-level autonomy is critical for ANTS and the objective of the proposed study is to work through the implications and constraints this entails. ANTS couples biologically inspired autonomic control for basic functions to higher level artificial intelligence that together enable individual spacecraft to operate as specialized, cooperative, social agents. This revolutionary approach postulates highly advanced, but familiar, components integrated and operated in a way that uniquely transcends any evolutionary extrapolation of existing trends and enables thousand-spacecraft missions.

The compositional diversity of non-Vesta basaltic asteroids

NASA Astrophysics Data System (ADS)

Leith, Thomas B.; Moskovitz, Nicholas A.; Mayne, Rhiannon G.; DeMeo, Francesca E.; Takir, Driss; Burt, Brian J.; Binzel, Richard P.; Pefkou, Dimitra

2017-10-01

We present near-infrared (0.78-2.45 μm) reflectance spectra for nine middle and outer main belt (a > 2.5 AU) basaltic asteroids. Three of these objects are spectrally distinct from all classifications in the Bus-DeMeo system and could represent spectral end members in the existing taxonomy or be representatives of a new spectral type. The remainder of the sample are classified as V- or R-type. All of these asteroids are dynamically detached from the Vesta collisional family, but are too small to be intact differentiated parent bodies, implying that they originated from differentiated planetesimals which have since been destroyed or ejected from the solar system. The 1- and 2-μm band centers of all objects, determined using the Modified Gaussian Model (MGM), were compared to those of 47 Vestoids and fifteen HED meteorites of known composition. The HEDs enabled us to determine formulas relating Band 1 and Band 2 centers to pyroxene ferrosilite (Fs) compositions. Using these formulas we present the most comprehensive compositional analysis to date of middle and outer belt basaltic asteroids. We also conduct a careful error analysis of the MGM-derived band centers for implementation in future analyses. The six outer belt V- and R-type asteroids show more dispersion in parameter space than the Vestoids, reflecting greater compositional diversity than Vesta and its associated bodies. The objects analyzed have Fs numbers which are, on average, between five and ten molar percent lower than those of the Vestoids; however, identification and compositional analysis of additional outer belt basaltic asteroids would help to confirm or refute this result. Given the gradient in oxidation state which existed within the solar nebula, these results tentatively suggest that these objects formed at either a different time or location than 4 Vesta.

Nine Galileo Views in Natural Color of Main-Belt Asteroid Ida

NASA Technical Reports Server (NTRS)

1997-01-01

This set of color images of asteroid 243 Ida was taken by the imaging system on the Galileo spacecraft as it approached and raced past the asteroid on August 28, 1993. These images were taken through the 4100-angstrom (violet), 7560-angstrom (infrared) and 9680- angstrom (infrared) filters and have been processed to show Ida as it would appear to the eye in approximately natural color. The stark shadows portray Ida's irregular shape, which changes its silhouetted outline when seen from different angles. More subtle shadings reveal surface topography (such as craters) and differences in the physical state and composition of the soil ('regolith'). Analysis of the images show that Ida is 58 kilometers long and 23 kilometers wide (36 x 14 miles). Ida is the first asteroid discovered to have a natural satellite, Dactyl (not shown here). Both Ida and Dactyl are heavily cratered by impacts with smaller asteroids and comets, including some of the same populations of small objects that bombard Earth. These data, combined with reflectance spectra from Galileo's near-infrared mapping spectrometer, may allow scientists to determine whether Ida is a relatively unaltered primitive object made of material condensed from the primordial Solar Nebula at the origin of the Solar System or whether it has been altered by strong heating--evidence interpreted so far suggests that Ida is a piece of a larger object that has been severely heated. Whereas heating and melting of large planets is well understood, the cause of heating of small asteroids is more enigmatic--it may have involved exotic processes that occurred only for a short time after the birth of the Sun and its planets.

Mission to the Trojan asteroids: Lessons learned during a JPL Planetary Science Summer School mission design exercise

NASA Astrophysics Data System (ADS)

Diniega, Serina; Sayanagi, Kunio M.; Balcerski, Jeffrey; Carande, Bryce; Diaz-Silva, Ricardo A.; Fraeman, Abigail A.; Guzewich, Scott D.; Hudson, Jennifer; Nahm, Amanda L.; Potter-McIntyre, Sally; Route, Matthew; Urban, Kevin D.; Vasisht, Soumya; Benneke, Bjoern; Gil, Stephanie; Livi, Roberto; Williams, Brian; Budney, Charles J.; Lowes, Leslie L.

2013-02-01

The 2013 Planetary Science Decadal Survey identified a detailed investigation of the Trojan asteroids occupying Jupiter's L4 and L5 Lagrange points as a priority for future NASA missions. Observing these asteroids and measuring their physical characteristics and composition would aid in identification of their source and provide answers about their likely impact history and evolution, thus yielding information about the makeup and dynamics of the early Solar System. We present a conceptual design for a mission to the Jovian Trojan asteroids: the Trojan ASteroid Tour, Exploration, and Rendezvous (TASTER) mission, that is consistent with the NASA New Frontiers candidate mission recommended by the Decadal Survey and the final result of the 2011 NASA-JPL Planetary Science Summer School. Our proposed mission includes visits to two Trojans in the L4 population: a 500 km altitude fly-by of 1999 XS143, followed by a rendezvous with and detailed observations of 911 Agamemnon at orbital altitudes of 1000-100 km over a 12 month nominal science data capture period. Our proposed instrument payload - wide- and narrow-angle cameras, a visual and infrared mapping spectrometer, and a neutron/gamma ray spectrometer - would provide unprecedented high-resolution, regional-to-global datasets for the target bodies, yielding fundamental information about the early history and evolution of the Solar System. Although our mission design was completed as part of an academic exercise, this study serves as a useful starting point for future Trojan mission design studies. In particular, we identify and discuss key issues that can make large differences in the complex trade-offs required when designing a mission to the Trojan asteroids.

Investigating the Geological History of Asteroid 101955 Bennu Through Remote Sensing and Returned Sample Analyses

NASA Technical Reports Server (NTRS)

Messenger, S.; Connolly, H. C., Jr.; Lauretta, D. S.; Bottke, W. F.

2014-01-01

The NASA New Frontiers Mission OSRIS-REx will return surface regolith samples from near-Earth asteroid 101955 Bennu in September 2023. This target is classified as a B-type asteroid and is spectrally similar to CI and CM chondrite meteorites [1]. The returned samples are thus expected to contain primitive ancient Solar System materials that formed in planetary, nebular, interstellar, and circumstellar environments. Laboratory studies of primitive astromaterials have yielded detailed constraints on the origins, properties, and evolutionary histories of a wide range of Solar System bodies. Yet, the parent bodies of meteorites and cosmic dust are generally unknown, genetic and evolutionary relationships among asteroids and comets are unsettled, and links between laboratory and remote observations remain tenuous. The OSIRIS-REx mission will offer the opportunity to coordinate detailed laboratory analyses of asteroidal materials with known and well characterized geological context from which the samples originated. A primary goal of the OSIRIS-REx mission will be to provide detailed constraints on the origin and geological and dynamical history of Bennu through coordinated analytical studies of the returned samples. These microanalytical studies will be placed in geological context through an extensive orbital remote sensing campaign that will characterize the global geological features and chemical diversity of Bennu. The first views of the asteroid surface and of the returned samples will undoubtedly bring remarkable surprises. However, a wealth of laboratory studies of meteorites and spacecraft encounters with primitive bodies provides a useful framework to formulate priority scientific questions and effective analytical approaches well before the samples are returned. Here we summarize our approach to unraveling the geological history of Bennu through returned sample analyses.

Using Recent Planetary Science Data to Develop Advanced Undergraduate Physics and Astronomy Activities

NASA Astrophysics Data System (ADS)

Steckloff, Jordan; Lindell, Rebecca

2016-10-01

Teaching science by having students manipulate real data is a popular trend in astronomy and planetary science education. However, many existing activities simply couple this data with traditional "cookbook" style verification labs. As with most topics within science, this instructional technique does not enhance the average students' understanding of the phenomena being studied. Here we present a methodology for developing "science by doing" activities that incorporate the latest discoveries in planetary science with up-to-date constructivist pedagogy to teach advanced concepts in Physics and Astronomy. In our methodology, students are first guided to understand, analyze, and plot real raw scientific data; develop and test physical and computational models to understand and interpret the data; finally use their models to make predictions about the topic being studied and test it with real data.To date, two activities have been developed according to this methodology: Understanding Asteroids through their Light Curves (hereafter "Asteroid Activity"), and Understanding Exoplanetary Systems through Simple Harmonic Motion (hereafter "Exoplanet Activity"). The Asteroid Activity allows students to explore light curves available on the Asteroid Light Curve Database (ALCDB) to discover general properties of asteroids, including their internal structure, strength, and mechanism of asteroid moon formation. The Exoplanet Activity allows students to investigate the masses and semi-major axes of exoplanets in a system by comparing the radial velocity motion of their host star to that of a coupled simple harmonic oscillator. Students then explore how noncircular orbits lead to deviations from simple harmonic motion. These activities will be field tested during the Fall 2016 semester in an advanced undergraduate mechanics and astronomy courses at a large Midwestern STEM-focused university. We will present the development methodologies for these activities, description of the activities, and results from the pre-tests.

Observations of Planet Crossing Asteroids

NASA Technical Reports Server (NTRS)

Tholen, David J.

1999-01-01

This grant funds the investigation of the Solar System's planet crossing asteroid population, principally the near Earth and trans-Neptunian objects, but also the Centaurs. Investigations include colorimetry at both visible and near infrared wavelengths, light curve photometry, astrometry, and a pilot project to find near Earth objects with small aphelion distances, which requires observations at small solar elongations.

Prediction and Confirmation of V-type Asteroids Beyond 2.5 AU Based on SDSS Colors

NASA Astrophysics Data System (ADS)

Binzel, Richard P.; Masi, G.; Foglia, S.

2006-09-01

We apply a taxonomic classification system developed by Masi et al. (2006, submitted to Icarus) to identify C-, S-, and V-type asteroids present within the 3rd Release of the Sloan Digital Sky Survey Moving Object Catalog (SDSS MOC3). The classifications deduced by Masi et al. for 43,000 asteroids using SDSS colors are based on the taxonomy of Bus (1999; MIT Ph.D. thesis). To link SDSS colors to the Bus taxonomy, Masi et al. (2006) use 149 objects measured in common by both SDSS and the Small Main-Belt Asteroid Spectroscopic Survey (SMASS) (Bus and Binzel 2002, Icarus 158, 106). We report results of direct testing of SDSS V-type classification predictions for six objects, where the tests were performed by visible wavelength spectroscopy (Lazzaro et al. 2004, Icarus 172, 179) and target of opportunity near-infrared spectroscopy obtained using the NASA Infrared Telescope Facility (IRTF). Vesta-like spectra and a V-type taxonomy are confirmed for five of the six predicted V-type objects sampled. Most interestingly, the SDSS taxonomy correctly predicted the V-type spectral characteristics for asteroid (21238) 1995 WV7, a 6 km asteroid located far from Vesta across the 3:1 mean motion resonance at 2.54 AU. (Proper elements a,e,i: 2.54 AU, 0.14, and 10.8 deg.) Given the 2 km/sec ejection velocity required from Vesta to reach the current orbit, and the difficulty of migrating across the 3:1 resonance (at 2.5 AU) by a process such as Yarkovsky drift or via secular resonances (Carruba et al. 2005, Astron. Astrophys. 441, 819), asteroid 21238 may be a new candidate for a basaltic asteroid having no relationship to Vesta.

THE 3–4  μ m SPECTRA OF JUPITER TROJAN ASTEROIDS

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

Brown, M. E., E-mail: mbrown@caltech.edu

To date, reflectance spectra of Jupiter Trojan asteroids have revealed no distinctive absorption features. For this reason, the surface composition of these objects remains a subject of speculation. Spectra have revealed, however, that the Jupiter Trojan asteroids consist of two distinct sub-populations that differ in the optical to near-infrared colors. The origins and compositional differences between the two sub-populations remain unclear. Here, we report the results from a 2.2–3.8 μ m spectral survey of a collection of 16 Jupiter Trojan asteroids, divided equally between the two sub-populations. We find clear spectral absorption features centered around 3.1 μ m in themore » less-red population. Additional absorption consistent with that expected from organic materials might also be present. No such features are see in the red population. A strong correlation exists between the strength of the 3.1 μ m absorption feature and the optical to near-infrared color of the objects. While, traditionally, absorptions such as these in dark asteroids are modeled as being due to fine-grain water frost, we find it physically implausible that the special circumstances required to create such fine-grained frost would exist on a substantial fraction of the Jupiter Trojan asteroids. We suggest, instead, that the 3.1 μ m absorption on Trojans and other dark asteroids could be due to N–H stretch features. Additionally, we point out that reflectivities derived from WISE observations show a strong absorption beyond 4 μ m for both populations. The continuum of 3.1 μ m features and the common absorption beyond 4 μ m might suggest that both sub-populations of Jupiter Trojan asteroids formed in the same general region of the early solar system.« less

The Chelyabinsk superbolide: a fragment of asteroid 2011 EO40?

NASA Astrophysics Data System (ADS)

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

2013-11-01

Bright fireballs or bolides are caused by meteoroids entering the Earth's atmosphere at high speed. Some have a cometary origin, a few may have originated within the Venus-Earth-Mars region as a result of massive impacts in the remote past but a relevant fraction is likely the result of the break-up of asteroids. Disrupted asteroids produce clusters of fragments or asteroid families and meteoroid streams. Linking a bolide to a certain asteroid family may help to understand its origin and pre-impact dynamical evolution. On 2013 February 15, a superbolide was observed in the skies near Chelyabinsk, Russia. Such a meteor could be the result of the decay of an asteroid and here we explore this possibility applying a multistep approach. First, we use available data and Monte Carlo optimization (validated using 2008 TC3 as template) to obtain a robust solution for the pre-impact orbit of the Chelyabinsk impactor (a = 1.62 au, e = 0.53, i = 3.82°, Ω = 326.41° and ω = 109.44°). Then, we use this most probable orbit and numerical analysis to single out candidates for membership in, what we call, the Chelyabinsk asteroid family. Finally, we perform N-body simulations to either confirm or reject any dynamical connection between candidates and impactor. We find reliable statistical evidence on the existence of the Chelyabinsk cluster. It appears to include multiple small asteroids and two relatively large members: 2007 BD7 and 2011 EO40. The most probable parent body for the Chelyabinsk superbolide is 2011 EO40. The orbits of these objects are quite perturbed as they experience close encounters not only with the Earth-Moon system but also with Venus, Mars and Ceres. Under such conditions, the cluster cannot be older than about 20-40 kyr.

Water transport to circumprimary habitable zones from icy planetesimal disks in binary star systems

NASA Astrophysics Data System (ADS)

Bancelin, D.; Pilat-Lohinger, E.; Maindl, T. I.; Bazsó, Á.

2017-03-01

So far, more than 130 extrasolar planets have been found in multiple stellar systems. Dynamical simulations show that the outcome of the planetary formation process can lead to different planetary architectures (i.e. location, size, mass, and water content) when the star system is single or double. In the late phase of planetary formation, when embryo-sized objects dominate the inner region of the system, asteroids are also present and can provide additional material for objects inside the habitable zone (HZ). In this study, we make a comparison of several binary star systems and aim to show how efficient they are at moving icy asteroids from beyond the snow line into orbits crossing the HZ. We also analyze the influence of secular and mean motion resonances on the water transport towards the HZ. Our study shows that small bodies also participate in bearing a non-negligible amount of water to the HZ. The proximity of a companion moving on an eccentric orbit increases the flux of asteroids to the HZ, which could result in a more efficient water transport on a short timescale, causing a heavy bombardment. In contrast to asteroids moving under the gravitational perturbations of one G-type star and a gas giant, we show that the presence of a companion star not only favors a faster depletion of our disk of planetesimals, but can also bring 4-5 times more water into the whole HZ. However, due to the secular resonance located either inside the HZ or inside the asteroid belt, impacts between icy planetesimals from the disk and big objects in the HZ can occur at high impact speed. Therefore, real collision modeling using a GPU 3D-SPH code show that in reality, the water content of the projectile is greatly reduced and therefore, also the water transported to planets or embryos initially inside the HZ.

A Large Program to derive the shape, cratering history and density of the largest main-belt asteroids

NASA Astrophysics Data System (ADS)

Marchis, Franck; Vernazza, Pierre; Marsset, Michael; Hanus, Josef; Carry, Benoit; Birlan, Mirel; Santana-Ros, Toni; Yang, Bin; and the Large Asteroid Survey with SPHERE (LASS)

2017-10-01

Asteroids in our solar system are metallic, rocky and/or icy objects, ranging in size from a few meters to a few hundreds of kilometers. Whereas we now possess constraints for the surface composition, albedo and rotation rate for all D≥100 km main-belt asteroids, the 3-D shape, the crater distribution, and the density have only been measured for a very limited number of these bodies (N≤10 for the first two). Characterizing these physical properties would allow us to address entirely new questions regarding the earliest stages of planetesimal formation and their subsequent collisional and dynamical evolution.ESO allocated to our program 152 hours of observations over 4 semesters to carry out disk-resolved observations of 38 large (D≥100 km) main-belt asteroids (sampling the four main compositional classes) at high angular-resolution with VLT/SPHERE throughout their rotation in order to derive their 3-D shape, the size distribution of the largest craters, and their density (PI: P. Vernazza). These measurements will allow investigating for the first time and for a modest amount of observing time the following fundamental questions: (A) Does the asteroid belt effectively hosts a large population of small bodies formed in the outer solar system? (B) Was the collisional environment in the inner solar system (at 2-3 AU) more intense than in the outer solar system (≥5AU)? (C) What was the shape of planetesimals at the end of the accretion process?We will present the goals and objectives of our program in the context of NASA 2014 Strategic Plan and the NSF decadal survey "Vision and Voyages" as well as the first observations and results collected with the SPHERE Extreme AO system. A detailed analysis of the shape modeling will be presented by Hanuš et al. in this session.

The Orbital Evolution of Near-Earth Asteroid 3753

NASA Astrophysics Data System (ADS)

Wiegert, Paul A.; Innanen, Kimmo A.; Mikkola, Seppo

1998-06-01

Asteroid 3753 (1986 TO) is in a 1:1 mean motion resonance with Earth, on a complex horseshoe-type orbit. Numerical experiments are performed to determine its medium-term stability and the means by which it may have entered its current orbit. Though 3753 moves primarily under the influence of the Sun and Earth, the giant planets (and Jupiter especially) play an important role by influencing, through torque-induced precession, the position of the asteroid's nodes. Variations in the nodal distance strongly affect the interaction of 3753 with Earth and may change or destroy the horseshoe-like behavior currently seen. This precession of the nodes provides a mechanism for placing minor planets into, or removing them from, a variety of horseshoe-type orbits. The chaotic nature of this asteroid's orbit makes predictions difficult on timescales longer than its Lyapunov time (~150 yr); therefore, ensembles of particles on orbits near that of 3753 are considered. The asteroid has a high probability of passing close to Venus and/or Mars on 10^4 yr timescales, pointing to a dynamical age much shorter than that of the solar system.

Design of optimal impulse transfers from the Sun-Earth libration point to asteroid

NASA Astrophysics Data System (ADS)

Wang, Yamin; Qiao, Dong; Cui, Pingyuan

2015-07-01

The lunar probe, Chang'E-2, is the first one to successfully achieve both the transfer to Sun-Earth libration point orbit and the flyby of near-Earth asteroid Toutatis. This paper, taking the Chang'E-2's asteroid flyby mission as an example, provides a method to design low-energy transfers from the libration point orbit to an asteroid. The method includes the analysis of transfer families and the design of optimal impulse transfers. Firstly, the one-impulse transfers are constructed by correcting the initial guesses, which are obtained by perturbing in the direction of unstable eigenvector. Secondly, the optimality of one-impulse transfers is analyzed and the optimal impulse transfers are built by using the primer vector theory. After optimization, the transfer families, including the slow and the fast transfers, are refined to be continuous and lower-cost transfers. The method proposed in this paper can be also used for designing transfers from an arbitrary Sun-Earth libration point orbit to a near-Earth asteroid in the Sun-Earth-Moon system.

Rotation Properties of Small Jovian Trojan Asteroids

NASA Astrophysics Data System (ADS)

French, Linda M.; Stephens, Robert D.; James, David; Coley, Daniel R.; Warner, Brian D.; Rohl, Derrick

2016-10-01

Jovian Trojan asteroids are of interest both as objects in their own right (we have no spectral analogs among meteorite samples) and as possible relics of Solar System formation. Asteroid lightcurves can give information about processes that have affected a group of asteroids; they can also give information about the density of the objects when enough lightcurves have been collected. We have been carrying out a survey of Trojan lightcurve properties for comparison with small asteroids and with comets. In a recent paper (French et al. 2015) we presented evidence that a significant number of Trojans have rotation periods greater than 24 hours. We will report our latest results and compare them with results of sparsely-sampled lightcurves from the Palomar Transient Factory (Waszczak et al. 2015). LF, RS, and DR were visiting astronomers at Cerro Tololo Interamerican Observatory, operated by AURA under contract with the NSF, and with the SMARTS Consortium at CTIO. This research was sponsored by NSF Planetary Astronomy grant 1212115.ReferencesFrench, L.M. et al. 2015. Icarus 254, pp. 1-17.Waszczak, A. et al. 2015. A.J. 150, Issue 3, I.D. 35.

The ginger-shaped asteroid 4179 Toutatis: new observations from a successful flyby of Chang'e-2.

PubMed

Huang, Jiangchuan; Ji, Jianghui; Ye, Peijian; Wang, Xiaolei; Yan, Jun; Meng, Linzhi; Wang, Su; Li, Chunlai; Li, Yuan; Qiao, Dong; Zhao, Wei; Zhao, Yuhui; Zhang, Tingxin; Liu, Peng; Jiang, Yun; Rao, Wei; Li, Sheng; Huang, Changning; Ip, Wing-Huen; Hu, Shoucun; Zhu, Menghua; Yu, Liangliang; Zou, Yongliao; Tang, Xianglong; Li, Jianyang; Zhao, Haibin; Huang, Hao; Jiang, Xiaojun; Bai, Jinming

2013-12-12

On 13 December 2012, Chang'e-2 conducted a successful flyby of the near-Earth asteroid 4179 Toutatis at a closest distance of 770 ± 120 meters from the asteroid's surface. The highest-resolution image, with a resolution of better than 3 meters, reveals new discoveries on the asteroid, e.g., a giant basin at the big end, a sharply perpendicular silhouette near the neck region, and direct evidence of boulders and regolith, which suggests that Toutatis may bear a rubble-pile structure. Toutatis' maximum physical length and width are (4.75 × 1.95 km) ±10%, respectively, and the direction of the +z axis is estimated to be (250 ± 5°, 63 ± 5°) with respect to the J2000 ecliptic coordinate system. The bifurcated configuration is indicative of a contact binary origin for Toutatis, which is composed of two lobes (head and body). Chang'e-2 observations have significantly improved our understanding of the characteristics, formation, and evolution of asteroids in general.

The Ginger-shaped Asteroid 4179 Toutatis: New Observations from a Successful Flyby of Chang'e-2

PubMed Central

Huang, Jiangchuan; Ji, Jianghui; Ye, Peijian; Wang, Xiaolei; Yan, Jun; Meng, Linzhi; Wang, Su; Li, Chunlai; Li, Yuan; Qiao, Dong; Zhao, Wei; Zhao, Yuhui; Zhang, Tingxin; Liu, Peng; Jiang, Yun; Rao, Wei; Li, Sheng; Huang, Changning; Ip, Wing-Huen; Hu, Shoucun; Zhu, Menghua; Yu, Liangliang; Zou, Yongliao; Tang, Xianglong; Li, Jianyang; Zhao, Haibin; Huang, Hao; Jiang, Xiaojun; Bai, Jinming

2013-01-01

On 13 December 2012, Chang'e-2 conducted a successful flyby of the near-Earth asteroid 4179 Toutatis at a closest distance of 770 ± 120 meters from the asteroid's surface. The highest-resolution image, with a resolution of better than 3 meters, reveals new discoveries on the asteroid, e.g., a giant basin at the big end, a sharply perpendicular silhouette near the neck region, and direct evidence of boulders and regolith, which suggests that Toutatis may bear a rubble-pile structure. Toutatis' maximum physical length and width are (4.75 × 1.95 km) ±10%, respectively, and the direction of the +z axis is estimated to be (250 ± 5°, 63 ± 5°) with respect to the J2000 ecliptic coordinate system. The bifurcated configuration is indicative of a contact binary origin for Toutatis, which is composed of two lobes (head and body). Chang'e-2 observations have significantly improved our understanding of the characteristics, formation, and evolution of asteroids in general. PMID:24336501

Orbit Alignment in Triple Stars

NASA Astrophysics Data System (ADS)

Tokovinin, Andrei

2017-08-01

The statistics of the angle Φ between orbital angular momenta in hierarchical triple systems with known inner visual or astrometric orbits are studied. A correlation between apparent revolution directions proves the partial orbit alignment known from earlier works. The alignment is strong in triples with outer projected separation less than ˜50 au, where the average Φ is about 20^\\circ . In contrast, outer orbits wider than 1000 au are not aligned with the inner orbits. It is established that the orbit alignment decreases with the increasing mass of the primary component. The average eccentricity of inner orbits in well-aligned triples is smaller than in randomly aligned ones. These findings highlight the role of dissipative interactions with gas in defining the orbital architecture of low-mass triple systems. On the other hand, chaotic dynamics apparently played a role in shaping more massive hierarchies. The analysis of projected configurations and triples with known inner and outer orbits indicates that the distribution of Φ is likely bimodal, where 80% of triples have {{Φ }}< 70^\\circ and the remaining ones are randomly aligned.

The Hawaii trails project: comet-hunting in the main asteroid belt

NASA Astrophysics Data System (ADS)

Hsieh, H. H.

2009-10-01

Context: The mysterious solar system object 133P/(7968) Elst-Pizarro is dynamically asteroidal, yet displays recurrent comet-like dust emission. Two scenarios were hypothesized to explain this unusual behavior: 1) 133P is a classical comet from the outer solar system that has evolved onto a main-belt orbit or 2) 133P is a dynamically ordinary main-belt asteroid on which subsurface ice has recently been exposed. If 1) is correct, the expected rarity of a dynamical transition onto an asteroidal orbit implies that 133P could be alone in the main belt. In contrast, if 2) is correct, other icy main-belt objects should exist and could also exhibit cometary activity. Aims: Believing 133P to be a dynamically ordinary, yet icy main-belt asteroid, I set out to test the primary prediction of the hypothesis: that 133P-like objects should be common and could be found by an appropriately designed observational survey. Methods: I conducted just such a survey - the Hawaii Trails Project - of selected main-belt asteroids in a search for objects displaying cometary activity. Optical observations were made of targets selected from among the Themis, Koronis, and Veritas asteroid families, the Karin asteroid cluster, and low-inclination, kilometer-scale outer-belt asteroids, using the Lulin 1.0 m, small and moderate aperture research telescope system (SMARTS) 1.0 m, University of Hawaii 2.2 m, southern astrophysical research (SOAR) 4.1 m, Gemini North 8.1 m, Subaru 8.2 m, and Keck I 10 m telescopes. Results: I made 657 observations of 599 asteroids, discovering one active object now known as 176P/LINEAR, leading to the identification of the new cometary class of main-belt comets (MBCs). These results suggest that there could be ~100 currently active MBCs among low-inclination, kilometer-scale outer-belt asteroids. Physically and statistically, MBC activity is consistent with initiation by meter-sized impactors. The estimated rate of impacts and sizes of resulting active sites, however, imply that 133P-sized bodies should become significantly devolatilized over Gyr timescales, suggesting that 133P, and possibly the other MBCs as well, could be secondary, or even multigenerational, fragments from recent breakup events. Some of the data presented herein were obtained at the W. M. Keck Observatory, the Gemini Observatory, Subaru Telescope, National Optical Astronomy Observatory (NOAO) facilities at the Cerro Tololo Inter-American Observatory, and Lulin Observatory. Keck is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration, and was made possible by the generous financial support of the W. M. Keck Foundation. Gemini is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the National Science Foundation (NSF) on behalf of the Gemini partnership. Subaru is operated by the National Astronomical Observatory of Japan. NOAO and Cerro Tololo are operated by the Association of Universities for Research in Astronomy, Inc., under co-operative agreement with the NSF. Lulin is supported and was made possible by the National Science Council of Taiwan, the Ministry of Education of Taiwan, and National Central University. Table [see full textsee full textsee full text] is available in its entirety in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/505/1297 Table 2 is only available in electronic form at http://www.aanda.org

A Mobile Asteroid Surface Scout (MASCOT) for the Hayabusa 2 Mission to 1999 JU3: The Scientific Approach

NASA Astrophysics Data System (ADS)

Jaumann, Ralf; Bibring, Jean-Pierre; Glassmeier, Karl-Heinz; Grott, Matthias; Ho, Tra-Mi; Ulamec, Stepahn; Schmitz, Nicole; Auster, Ulrich; Biele, Jens; Kuninaka, Hitoshi; Okada, Tatsuaki; Yoshikawa, Makoto; Watanabe, Sei-ichhiro; Fujimoto, Masaki; Spohn, Tilman; Koncz, Alexander; Michaelis, Harald

2014-05-01

MASCOT, a Mobile Asteroid Surface Scout, will support JAXA's Hayabusa 2 mission to investigate the C-type asteroid 1999 JU3 (1). The German Aer-ospace Center (DLR) develops MASCOT with contributions from CNES (France) (2,3). Main objective is to in-situ map the asteroid's geomorpholo-gy, the intimate structure, texture and composition of the regolith (dust, soil and rocks), and the thermal, mechanical, and magnetic properties of the sur-face in order to provide ground truth for the orbiter remote measurements, support the selection of sampling sites, and provide context information for the returned samples. MASCOT comprises a payload of four scientific in-struments: camera, radiometer, magnetometer and hyperspectral microscope. C- and D-type asteroids hold clues to the origin of the solar system, the for-mation of planets, the origins of water and life on Earth, the protection of Earth from impacts, and resources for future human exploration. C- and D-types are dark and difficult to study from Earth, and have only been glimpsed by spacecraft. While results from recent missions (e.g., Hayabusa, NEAR (4, 5, 6)) have dramatically increased our understanding of asteroids, important questions remain. For example, characterizing the properties of asteroid regolith in-situ would deliver important ground truth for further understanding telescopic and orbital observations and samples of such aster-oids. MASCOT will descend and land on the asteroid and will change its position two times by hopping. This enables measurements during descent, at the landing and hopping positions #1-3, and during hopping. References: (1) Vilas, F., Astronomical J. 1101-1105, 2008; (2) Ulamec, S., et al., Acta Astronautica, Vol. 93, pp. 460-466; (3) Jaumann et al., 45th LPSC, Houston; (4) Special Issue, Science, Vol. 312 no. 5778, 2006; (5) Special Issue Science, Vol. 333 no. 6046, 2011. (6) Bell, L., Mitton, J-., Cambridge Univ. Press, 2002.

A Mobile Asteroid Surface Scout (MASCOT) for the Hayabusa 2 Mission to 1999 JU3: The Scientific Approach

NASA Astrophysics Data System (ADS)

Jaumann, Ralf; Bibring, Jean-Pierre; Glassmeier, Karl-Heinz; Grott, Matthias; Ho, Tra-Mie; Ulamec, Stephan; Schmitz, Nicole; Auster, Hans-Ulrich; Biele, Jens; Kuninaka, Hitoshi; Okada, Tatsuaki; Yoshikawa, Makoto; Watanabe, Sei-ichhiro; Fujimoto, Masaki; Spohn, Tilman

2013-04-01

Mascot, a Mobile Asteroid Surface Scout, will support JAXA's Hayabusa 2 mission to investigate the C-type asteroid 1999 JU3 (1). The German Aero-space Center (DLR) develops Mascot with contributions from CNES (France) (2). Main objective is to in-situ map the asteroid's geomorphology, the intimate structure, texture and composition of the regolith (dust, soil and rocks), and the thermal, mechanical, and magnetic properties of the surface in order to provide ground truth for the orbiter remote measurements, sup-port the selection of sampling sites, and provide context information for the returned samples. Mascot comprises a payload of four scientific instruments: camera, radiometer, magnetometer and hyperspectral microscope. C- and D-type asteroids hold clues to the origin of the solar system, the formation of planets, the origins of water and life on Earth, the protection of Earth from impacts, and resources for future human exploration. C- and D-types are dark and difficult to study from Earth, and have only been glimpsed by spacecraft. While results from recent missions (e.g., Hayabusa, NEAR (3, 4, 5)) have dramatically increased our understanding of asteroids, important questions remain. For example, characterizing the properties of asteroid reg-olith in-situ would deliver important ground truth for further understanding telescopic and orbital observations and samples of such asteroids. Mascot will descend and land on the asteroid and will change its position two times by hopping. This enables measurements during descent, at the landing and hopping positions #1-3, and during hopping. References: (1) Vilas, F., Astronomical J. 1101-1105, 2008; (2) Ulamec, S., et al., COSPAR, General Assembly, Mysore/India, 2012; (3) Special Issue, Science, Vol. 312 no. 5778, 2006; (4) Special Issue Science, Vol. 333 no. 6046, 2011; (5) Bell, L., Mitton, J-., Cambridge Univ. Press, 2002.

Unveiling Clues from Spacecraft Missions to Comets and Asteroids through Impact Experiments

NASA Technical Reports Server (NTRS)

Lederer, Susan M.; Jensen, Elizabeth; Fane, Michael; Smith, Douglas; Holmes, Jacob; Keller, Lindasy P.; Lindsay, Sean S.; Wooden, Diane H.; Whizin, Akbar; Cintala, Mark J.;

Scientific Packages on Small Bodies, a Deployment Strategy for New Missions

NASA Astrophysics Data System (ADS)

Tardivel, Simon; Scheeres, D. J.; Michel, P.

2013-10-01

The exploration of asteroids is currently a topic of high priority for the space agencies. JAXA will launch its second asteroid explorer, aimed at 1999 JU3, in the second half of 2014. NASA has selected OSIRIS-REx to go to asteroid Bennu, and it will launch in 2016. ESA is currently performing the assessment study of the MarcoPolo-R space mission, in the framework of the M3 (medium) competition of its Cosmic Vision Program, whose objective is now 2008 EV5. In the continuity of these missions, landing for an extended period of time on the ground to perform measurements seems a logical next step to asteroid exploration. Yet, the surface behavior of an asteroid is not well known and landing the whole spacecraft on it could be hazardous, and pose other mission operations problems such as ensuring communication with Earth. Hence, we propose a new approach to asteroid surface exploration. Using a mothership spacecraft, we will present how multiple landers could be deployed to the surface of an asteroid using ballistic trajectories. Combining a detailed simulation of the bouncing and contact dynamics on the surface with numerical and mathematical analysis of the flight dynamics near an asteroid, we show how landing pods could be distributed at the surface of a body. The strategy has the advantages that the mothership always maintains a safe distance from the surface and the landers do not need any GNC (guidance, navigation and control system) or landing apparatus. Thus, it allows for simple operations and for the design of lightweight landers with minimum platform overhead and maximum payload. These pods could then be used as a single measurement apparatus (e.g. seismometers) or as independent and different instruments, using their widespread distribution to gain both global and local knowledge on the asteroid.