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NASA NTRS2021

Astromaterial Curation and Research at NASA

Astromaterial sample return missions from other planetary bodies (e.g., the Moon, asteroids, the Sun) and astromaterial sample collection missions here on Earth (e.g., Antarctic Meteorites, Cosmic Dust) have been a vital part of NASA’s science vision since nearly its inception. Beginning with the Apollo missions to the Moon and extending to the recent successful sample collection by the OSIRIS-REx asteroid sample return mission, these astromaterials collections have been an invaluable resource to scientists and educators around the world. Sample studies continue to provide fundamental insight into how our solar system and its constituent bodies formed and evolved over the past 4.5 billion years. As evidence of their broad impact, there are over 19,141 samples on loan to 433 Principal Investigators in 24 countries [1]. As we plan for exploration missions through 2050, sample return missions will continue to play a vital role in NASA’s science vision. Returned samples truly are the gift that keeps on giving. Having the samples accessible on Earth allows new generations of scientists and new generations of instrumentation to pursue ever evolving scientific questions. For example, the Apollo samples were collected ~50 years ago, yet our views of how the Earth-Moon system formed, the role of volatiles in the early inner solar system, and even the positions of the gas giants in the outer solar system have changed dramatically as a result of Apollo sample analyses conducted very recently. Vital to the long-term viability of any sample return mission is the careful curation of the samples. Curatorial efforts need to begin early in the project lifecycle, not with the return of the samples, but at mission conception. The Astromaterials Acquisition and Curation Office at NASA Johnson Space Center is responsible for curating all of NASA’s current and future extraterrestrial samples. Looking at possible sample return missions over the next 35+ years [2], many samples would require curation efforts a step beyond current capabilities, e.g., cold or cryogenic curation, organically and biologically clean curation, curation of gases and ices, and curation of samples with extreme pressure, temperature, or redox requirements. During the lecture, we discuss the current curatorial efforts in JSC curation, as well as discoveries from the astromaterial research. [1] Zeigler, R. A. et al. (2017) Planetary Science Vision 2050 Workshop. [2] McCubbin F. M. et al. (2017) Planetary Science Vision 2050 Workshop.

astromaterial↗
NASA NTRS1972

Lunar composition as a clue to the early history of the solar system.

The apparent conflict of the low iron content of the moon with the hypothesis of lunar capture is shown to be reconcilable if, in the inner solar system, iron condensations are assumed to conglomerate into planetary cores before the silicates condense to form a number of iron-poor moons. In the outer solar system, there would be no such fractionation, and, in the asteroid belt, the situation should be intermediate and quite complex. A crucial parameter is the ratio of coalescence time to cooling time, which depends on the density of the solar nebula. Also of importance are nonuniform cooling and condensation, as well as the outward transport of volatiles and their dissipation from the solar system. The model can explain also other features of the planets and asteroids.

Singer, S. F.↗
NASA NTRS1973

The early evolution of the solar system

The problems of relating collapse conditions in an interstellar cloud to a model of the primitive solar nebula are discussed. In such a nebula there is a radial force balance between gravity, the pressure gradient, and centrifugal forces due to the rotation. Approximate values are given for the combinations of temperature and density throughout the nebula, from a maximum of about 2000 K near the center to less than 200 K in the outer portion. These conditions are based upon the compression adiabats in the terminal stages of the collapse of an interstellar cloud. One general conclusion, of great importance for accumulation of bodies within the solar system, is that interstellar grains should not be completely evaporated at distances in the nebula beyond about one or more astronomical units.

Cameron, A. G. W.↗
NASA NTRS1985

Voyager Saturnian ring measurements and the early history of the solar system

The mass distribution in the Saturnian ring system is investigated and compared with predictions from plasma cosmogony. According to this theory, the matter in the rings was once a magnetized plasma, in which gravitation is balanced by the centrifugal and electromagnetic forces. As the plasma is neutralized, the electromagnetic forces disappear and the matter falls in to 2/3 of the original saturnocentric distance. This causes the cosmogonic shadow effect, demonstrated for the large scale structure of the Saturnian ring system. It is shown that many structures of the present ring system can be understood as shadows and antishadows of cosmogonic origin. These appear in the form of double rings centered around a position a factor 0.64 (slightly 2/3) closer to Saturn than the causing feature. Voyager data agree with an accuracy 1%.

Alfven, H.↗
NASA NTRS1986

Voyager Saturnian ring measurements and the early history of the solar system

The mass distribution in the Saturnian ring system is investigated and compared with predictions from the plasma cosmogony. According to this theory, the matter in the rings has once been in the form of a magnetized plasma, in which the gravitation is balanced partly by the centrifugal force and partly by the electromagnetic forces. As the plasma is neutralized, the electromagnetic forces disappear and the matter can be shown to fall in to 2/3 of the original saturnocentric distance. This causes the so called 'cosmogonic shadow effect', which has been demonstrated earlier for the asteroidal belt and in the large scale structure of the Saturnian ring system. The relevance of the cosmogonic shadow effect is investigated for parts of the fine structures of the Saturnian ring system. It is shown that many structures of the present ring system can be understood as shadows and antishadows of cosmogonic origin. These appear in the form of double rings centered around a position a factor 0.64 (slightly less than 2/3) closer to Saturn than the causing feature. Voyager data agree with an accuracy better than 1 percent.

Alfven, H.↗
NASA NTRS1988

Lewis Cliff 86010, a unique Antarctic meteorite: Possible new clues to the early history of the solar system

Results form the Antarctic sample, LEW 86010 indicate that it is an extremely interesting meteorite of clear igneous origin, and is probably closely related to ADOR. Several important questions await further detailed study. The most stringent test of the relationship to ADOR will come from the measurement of the oxygen isotopic composition. One possibility proposed is that LEW 86010 represents a partial or total melt of a mixture of material similar to the white Allende clasts and more ordinary chondritic meteorite material. Several lines of investigation will contribute to resolve this question. Further melting studies will be performed to determine whether LEW 86010 represents molten lava. In addition to test the connection with Allende, isotopic studies will look for anomalous isotopic compositions which are ubiquitous in Allende white inclusions. All of these studies will be performed on a tiny sample which weights only 5 grams, and is smaller than a marble, but which contains important clues to events which occurred during the birth of the solar system.

Mckay, G. A.↗
NASA NTRSDate not supplied

Early History of the Solar System Revealed By Calcium-48 Heterogeneity in Calcium-Aluminium-Rich Inclusions

Introduction: Calcium-aluminum-rich inclusions (CAIs) are the earliest formed solids in the solar system. Although the mineralogy of CAIs is consistent with condensation from a solar composition gas, textural, elemental and isotopic signatures point to CAIs having more complicated thermal histories rather than simply being primary condensates. Untangling the condensation record in these refractory inclusions and the associated physicochemical environment, can provide insights into temporal and/or spatial reservoirs in the protoplanetary disk where solids were forming.

R M G Armytage↗
NASA NTRS1988

Boundary conditions for the origin of the solar system

From the meteoritic results presented in the preceding chapters, a set of boundary conditions is identified that can be applied, with variable degrees of confidence, as constraints to models that attempt to describe the origin and early evolution of the solar system. Those constraints bear upon the time scale, physical and chemical environment, and processes that characterized the early solar system.

Kerridge, John F.↗
NASA NTRS1986

Space station impact experiments

Four processes serve to illustrate potential areas of study and their implications for general problems in planetary science. First, accretional processes reflect the success of collisional aggregation over collisional destruction during the early history of the solar system. Second, both catastrophic and less severe effects of impacts on planetary bodies survivng from the time of the early solar system may be expressed by asteroid/planetary spin rates, spin orientations, asteroid size distributions, and perhaps the origin of the Moon. Third, the surfaces of planetary bodies directly record the effects of impacts in the form of craters; these records have wide-ranging implications. Fourth, regoliths evolution of asteroidal surfaces is a consequence of cumulative impacts, but the absence of a significant gravity term may profoundly affect the retention of shocked fractions and agglutinate build-up, thereby biasing the correct interpretations of spectral reflectance data. An impact facility on the Space Station would provide the controlled conditions necessary to explore such processes either through direct simulation of conditions or indirect simulation of certain parameters.

Schultz, P.↗
NASA NTRS2016

Evidence for a Heterogeneous Distribution of Water in the Martian Interior

The abundance and distribution of H2O within the terrestrial planets, as well as its timing of delivery, is a topic of vital importance for understanding the chemical and physical evolution of planets and their potential for hosting habitable environments. Analysis of planetary materials from Mars, the Moon, and the eucrite parent body (i.e., asteroid 4Vesta) have confirmed the presence of H2O within their interiors. Moreover, H and N isotopic data from these planetary materials suggests H2O was delivered to the inner solar system very early from a common source, similar in composition to the carbonaceous chondrites. Despite the ubiquity of H2O in the inner Solar System, the only destination with any prospects for past or present habitable environments at this time, outside of the Earth, is Mars. Although the presence of H2O within the martian interior has been confirmed, very little is known regarding its abundance and distribution within the martian interior and how the martian water inventory has changed over time. By combining new analyses of martian apatites within a large number of martian meteorite types with previously published volatile data and recently determined mineral-melt partition coefficients for apatite, we report new insights into the abundance and distribution of volatiles in the martian crust and mantle. Using the subset of samples that did not exhibit crustal contamination, we determined that the enriched shergottite mantle source has 36-73 ppm H2O and the depleted shergottite mantle source has 14-23 ppm H2O. This result is consistent with other observed geochemical differences between enriched and depleted shergottites and supports the idea that there are at least two geochemically distinct reservoirs in the martian mantle. We also estimated the H2O content of the martian crust using the revised mantle H2O abundances and known crust-mantle distributions of incompatible lithophile elements. We determined that the bulk martian crust has approximately 1400 ppm H2O, which is likely distributed toward the martian surface. This crustal water abundance would equate to a global equivalent layer (GEL) of water at a depth of-229 m, which can account for at least some of the surface features on Mars attributed to flowing water and may be sufficient to support the past presence of a shallow sea on Mars' surface.

McCubbin, Francis↗
NASA NTRS1994

The impactor flux in the Pluto-Charon system

Current impact rates of comets on Pluto and Charon are estimated. It is shown that the dominant sources of impactors are comets from the Kuiper belt and the inner Oort cloud, each of whose perihelion distribution extends across Pluto's orbit. In contrast, long-period comets from the outer Oort cloud are a negligible source of impactors. The total predicted number of craters is not sufficient to saturate the surface areas of either Pluto of Charon over the age of the Solar System. However, heavy cratering may have occurred early in the Solar System's history during clearing of planetesimals from the outer planets' zone.

Weissman, Paul R.↗
NASA NTRS2008

Collisional Processing of Olivine and Pyroxene in Cometary Dust

According to the nebular theory of solar-system formation, collisions between bodies occurred frequently early in the solar system s history and continue at a lower rate even today. Collisions have reworked the surface compositions and structures of cometary nuclei, though to an unknown degree. The majority of the collisional history of a typical Jupiter-family comet takes place while it resides in the Kuiper Belt. Impacts occur on the surfaces of small bodies over a large range of velocities by impactors of all sizes, but typical encounter speeds within the Kuiper Belt are 1.5 to 2.0 km/s[1]. Durda and Stern suggest that the interiors of most cometary nuclei with diameters <5 km have been heavily damaged by collisions [2]. They estimate that over a period of 3.5 Gy, a nucleus with a diameter of 2 km and an orbit between 35-45 AU will experience 90-300 collisions with objects greater than 8 m in diameter. In this same time interval, collisions between a typical Trans-Neptunian Object (TNO) 200 km in diameter and objects with d > 8 m would rework up to one-third of that TNO s surface. In fact, it has been proposed that most short-period comets from the Kuiper Belt (90%) are collisional fragments from larger TNOs - not primordial objects themselves [3] - and that most short-period comets from the Kuiper Belt will be collisionally processed both on their surfaces as well as in their interiors.

Lederer, S. M.↗
NASA NTRS1987

Meteorite spectroscopy and characterization of asteroid surface materials

The purpose of this research effort is to improve the understanding of the origin, evolution, and interrelationships of the asteroids; of their relationships to the meteorites; and of the conditions and processes in the early inner solar system. The surface mineral assemblage and the surface heterogeneity of selected minor planets is determined from analysis of telescopic spectra to provide the data base to accomplish these goals. The analysis of asteroidal visible and near-infrared (VNIR) reflectance spectra compliments meteorite studies as a means of probing the late nebular through the early post-accretionary period of solar system history. To date, essentially all available spectral evidence has strongly indicated that the large S-type asteroids are predominantly thermally evolved, magmatically differentiated bodies.

Gaffey, Michael J.↗
NASA NTRS2011

NASA's Dawn Mission to Asteroid 4 Vesta

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.

McFadden, Lucyann A.↗