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NASA NTRS2003

The Meteoritic Component in Impact Deposits

This proposal requested support for a broad-based research program designed to understand the chemical and mineralogical record of accretion of extraterrestrial matter to the Earth. The primary goal of this research is to study the accretion history of the Earth, to understand how this accretion history reflects the long-term flux of comets, asteroids, and dust in the inner solar system and how this flux is related to the geological and biological history of the Earth. This goal is approached by seeking out the most significant projects that can be attacked utilizing the expertise of the PI and potential collaborators. The greatest expertise of the PI is the analysis of meteoritic components in terrestrial sediments. This proposal identifies three primary areas of research, involving impact events in the early Archean (3.2 Ga), the late Eocene (35 Ma) and the late Pliocene (2 Ma). In the early Archean we investigate sediments that contain the oldest recorded impacts on Earth. These are thick spherule beds, three of which were deposited within 20 m.y. If these are impact deposits the flux of objects to Earth at this time was much greater than predicted by current models. Earlier work used Cr isotopes to prove that one of these contain extraterrestrial matter, from a projectile with Cr isotopes similar to CV chondrites. We planned to expand this work to other spherule beds and to search for additional evidence of other impact events. With samples from D. Lowe (Stanford Univ.) the PI proposed to screen samples for high Ir and Cr so that appropriate samples can be provided to A. Shukolyukov for Cr-isotopic analyses. This work was expected to provide evidence that at least one interval in the early Archean was a period of intense bombardment and to characterize the composition of objects accreted. The late Eocene is also a period of intense bombardment with multiple spherule deposits and two large craters. Farley et al. (1998) demonstrated an increased (3)He flux to marine sediments that was attributed to an increase in interplanetary dust due to a shower of comets invading the inner solar system. We planned to detect a change in the Cr-isotopic composition in the flux of fine-grained extraterrestrial matter to ocean sediments. This would provide evidence for the comet shower hypothesis. We planned attempt to locate late Eocene impact deposits in a new high resolution, hi-latitude site that had the potential for excellent preservation and new information of the sources and effects of these impacts. Although most impacts on Earth occur in deep-ocean basins, only one such event is known - the late Pliocene impact of the Eltanin asteroid. The ejecta from this impact includes Ir- rich impact melt, spherules, and actual meteorites from the km-sized mesosiderite asteroid. Through a study of the ejecta, we can learn about the formation, distribution, alteration and preservation of Ir-rich deposits. We can also learn about meteorite survival during hypervelocity impacts and we can study pieces of a km-sized object to learn more about the mesosiderite parent body. Analyses of sediment cores and geophysical exploration of the impact site can further our understanding of the processes involved in deep-ocean impacts and potential effects on the terrestrial climate and biosphere. We planned analyses of this ejecta, a search for ejecta 5000 km distant from the impact area, and a new oceanographic expedition to study and sample the impact site. In addition to these three specific areas of research, the PI planned to remain flexible and available to exploit new opportunities presented by new discoveries, and to engage in new collaborations if other researchers require his expertise to develop new projects that fit within the objectives of the overall research program.

Kyte, Frank T.↗
NASA NTRS1994

Innovative instrumentation for mineralogical and elemental analyses of solid extraterrestrial surfaces: The Backscatter Moessbauer Spectrometer/X Ray Fluorescence analyzer (BaMS/XRF)

We have developed a four-detector research-grade backscatter Moessbauer spectrometer (BaMS) instrument with low resolution x-ray fluorescence analysis (XRF) capability. A flight-qualified instrument based on this design would be suitable for use on missions to the surfaces of solid solar-system objects (Moon, Mars, asteroids, etc.). Target specifications for the flight instrument are as follows: mass less than 500 g; volumes less than 300 cu cm; and power less than 2 W. The BaMS/XRF instrument would provide data on the oxidation state of iron and its distribution among iron-bearing mineralogies and elemental composition information. This data is a primary concern for the characterization of extraterrestrial surface materials.

Shelfer, T. D.↗
NASA NTRS2022

The breakup of a long-period comet is not a likely match to the Chicxulub impactor

Since the discovery of Ir in the clay layer at the K-Pg boundary, scientists have sought to constrain the origin of the extraterrestrial impactor that triggered the end-Cretaceous mass extinction of the non-avian dinosaurs and other species. While the first proposal was for an asteroid, for a while some theories invoked a cometary impactor to explain perceived periodicities in mass extinctions. Such models have long been disfavored by the mass of Ir in the layer, inferred to be 2.0−2.8×10^(11)cu.g. The size of the Chicxulub crater leads to an estimated asteroid impactor diameter, D≈10km. Comets typically impact at higher speeds, reducing the impactor mass for the same impact energy. Although it is increasingly recognized that a continuum exists between comets and asteroids, ’comets’ are considered to be more ice-rich (estimates for 67P/Churyumov-Gerasimenko are about 20%;), implying lower Ir contents per impactor mass. A carbonaceous chondrite-like asteroid of the appropriate size would likely deliver ≈2.3×10^(11)g of Ir, in the center of the estimated mass range of the global Ir layer; but a comet would only deliver ∼0.1×10^(11)g, because it would be less massive. Although these conclusions are long standing, Siraj and Loeb have recently argued anew in favor of a comet over an asteroid, based on dynamical and geochemical evidence. Here we demonstrate that their arguments are based on misinterpretations of the literature, and that an asteroid is in fact still highly favored over a comet.

Steven J. Desch↗
NASA NTRS2022

The breakup of a long-period comet is not a likely match to the Chicxulub impactor

Since the discovery of Ir in the clay layer at the K-Pg boundary [1], scientists have sought to constrain the origin of the extraterrestrial impactor that triggered the end-Cretaceous mass extinction of the non-avian dinosaurs and other species. While the first proposal was for an asteroid, for a while some theories invoked a cometary impactor to explain perceived periodicities in mass extinctions. Such models have long been disfavored by the mass of Ir in the layer, inferred to be2.0−2.8×1011g. The size of Chicxulub crater leads to an estimated asteroid impactor diameter,D≈10 km. Comets typically impact at higher speeds, reducing the impactor mass for the same impact energy. Although it is increasingly recognized that a continuum exists between comets and asteroids, ’comets’ are considered to be more ice-rich (estimates for67P/ Churyumov-Gerasimenko are about 20%;), implying lower Ir contents per impactor mass. A carbonaceous chondrite-like asteroid of the appropriate size would likely deliver≈2.3×1011gof Ir, in the center of the estimated mass range of the global Ir layer; but a comet would only deliver∼0.1×1011g, because it would be less massive. Although these conclusions are long standing, Siraj & Loeb have recently argued anew in favor of a comet over an asteroid, based on dynamical and geochemical evidence. Here we demonstrate that their arguments are based on misinterpretations of the literature, and that an asteroid is in fact still highly favored over a comet.

Steven J Desch↗
NASA NTRS2016

Instrument for Analysis of Organic Compounds on Other Planets

The goal of this project is to develop the Instrument for Solvent Extraction and Analysis of Extraterrestrial Bodies using In Situ Resources (ISEE). Specifically, ISEE will extract and characterize organic compounds from regolith which is found on the surface of other planets or asteroids. The techniques this instrument will use are supercritical fluid extraction (SFE) and supercritical fluid chromatography (SFC). ISEE aligns with NASA's goal to expand the frontiers of knowledge, capability, and opportunities in space in addition to supporting NASA's aim to search for life elsewhere by characterizing organic compounds. The outcome of this project will be conceptual designs of 2 components of the ISEE instrument as well as the completion of proof-of-concept extraction experiments to demonstrate the capabilities of SFE. The first conceptual design is a pressure vessel to be used for the extraction of the organic compounds from the regolith. This includes a comparison of different materials, geometry's, and a proposition of how to insert the regolith into the vessel. The second conceptual design identifies commercially available fluid pumps based on the requirements needed to generate supercritical CO2. The proof-of-concept extraction results show the percent mass lost during standard solvent extractions of regolith with organic compounds. This data will be compared to SFE results to demonstrate the capabilities of ISEE's approach.

supercritical fluids↗
NASA NTRS2018

Experimental Study into the Stability of Whitlockite and Hydroxylapatite in Basaltic Magmas

Apatite (Ca5(PO4)3(F,Cl,OH)), merrillite (Ca18Na2Mg2(PO4)14), and whitlockite (Ca9(Mg,Fe(2+))(PO4)6[PO3(OH)]) are the primary phosphate minerals found in most planetary materials including rocks from Earth, Moon, Mars, and asteroids. For many years, the terms merrillite and whitlockite have been used interchangeably in the meteorite literature. Much of the confusion regarding the relationship between terrestrial and extraterrestrial 'whitlockite' is based on the presence or absence of hydrogen in the mineral structure. Whitlockite has approximately 8500 ppm H2O, and the term 'merrillite' has been adopted to identify the hydrogen-free form of whitlockite. The atomic structures of merrillite and whitlockite were examined in detail by Hughes et al.. On Earth, whitlockite has been found in rocks from evolved pegmatitic systems and in some mantle rocks. Furthermore, terrestrial whitlockite has been shown to have some merrillite component. For the meteoritic and lunar materials that have been investigated, merrillite appears to be far more common than whitlockite, and it has been proposed that the whitlockite component is unique to terrestrial samples. There are some reports of 'whitlockite' in the meteorite literature; however, these may represent misidentifications of merrillite because there have been no reports of extraterrestrial whitlockite that have been verified through crystal structural studies or analyzed for their H contents. Hughes et al. reported the atomic arrangement of lunar merrillite and demonstrated that the phase is similar to meteoritic merrillite and, predictably, devoid of hydrogen. In a follow-up study, Hughes et al. reported the atomic arrangements of two natural samples of whitlockite, one synthetic whitlockite, and samples of synthetic whitlockite that were heated at 500 C or 1050 C for 24 h. The crystal chemistry and crystal structures of the phases were compared, and it was discovered that the latter treatment resulted in the dehydrogenation of whitlockite to form merrillite.

McCubbin, F. M.↗
NASA NTRS2001

Continued Investigations of the Accretion History of Extraterrestrial Matter over Geologic Time

This grant supported our ongoing project to characterize the accretion rate of interplanetary dust particles (IDPs) to Earth over geologic time using He-3 as a tracer. IDPs are derived from collisions in the asteroid belt and from disaggregation of active comets. Owing to their small size (few to few hundred micrometers diameter) these particles spiral into the sun under Poynting-Robertson drag typically in less than a few tens of kyrs. Thus IDPs must be continually resupplied to the zodiacal cloud, and because the processes of IDP production are likely to be sporadic, time variation in the IDP accretion rate to Earth is likely to be time-varying. For example, major asteroidal collisions and comet showers should greatly enhance the IDP accretion rate. Our ultimate objective (still ongoing) is to document this time variance so as to better understand the history of the solar system, the source of IDPs accreting to Earth, and the details of the mechanism by which particles are captured by Earth. To document variations in IDP accretion rate through time we use He-3 as a tracer. This isotope is in extremely low abundance in terrestrial matter, but IDPs have very high concentrations of He-3 from implantation of solar wind ions. By measuring He-3 in seafloor sediments, we can estimate the IDP accretion rate for at least the last few hundred Myrs. Under an earlier NASA grant we identified the existence of a large increase in He-3 flux in the Late Eocene (35 Myr ago), coincident with the two largest impact craters of the Cenozoic Era. The simplest interpretation of this observation is the occurrence of a shower of long period comets at that time, simultaneously increasing the impact cratering probability and accretion rate of IDPs to Earth (Farley et al., 1998). Comet showers produced by stellar perturbation of the Oort cloud should be fairly common in the geologic record, so this is not an unreasonable interpretation of our observations.

Farley, Kenneth↗
NASA NTRS1991

Coproduction of volatiles and metals from extraterrestrial materials

Two main efforts in support of the general goals of SERC/culpr are presented. Investigations of processes for the coproduction of metals from extra-terrestrial materials in conjunction with plausible schemes for oxygen extraction continue. The principal emphasis was on the extraction and purification of iron from the ilmenite reduction process for oxygen, from the cathode metal deposits made in the magma electrolysis process for oxygen, and from native ferrous metal alloys on the moon and asteroids. All work on the separation and purification of ferrous metals was focussed upon the gaseous carbonyl process, a scheme that involves only temperatures attainable by passive thermal control. The exploration of a variety of schemes was initiated, involving the use of several different propulsion options and both propulsive and aerobraking capture at earth, for return of extraterrestrial resources to earth orbits. In addition, the search for new opportunities in space resource utilization continues. Examples include the continuation of work underway on: (1) the feasibility of locating solar power satellites in highly eccentric earth orbit; (2) the energetics of extracting the potential clean fusion fuel He-3 from the atmosphere for return to earth; and (3) the utility of a nuclear steam rocket (using non-terrestrial water as the working fluid) for transportation in the inner solar system.

Lewis, John S.↗
NASA NTRS2014

Water Transport and the Evolution of CM Parent Bodies

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.

Coker, R.↗
NASA NTRS2017

Search for Primitive Matter in the Solar System

Recent astronomical observations and theoretical modeling led to a consensus regarding the global scenario of the formation of young stellar objects (YSO) from a cold molecular cloud of interstellar dust (organics and minerals) and gas that, in some cases, leads to the formation of a planetary system. In the case of our Solar System, which has already evolved for approximately 4567 Ma, the quest is to access, through the investigation of planets, moons, cometary and asteroidal bodies, meteorites, micrometeorites, and interplanetary dust particles, the primitive material that contains the key information about the early Solar System processes and its evolution. However, laboratory analyses of extraterrestrial samples, astronomical observations and dynamical models of the Solar System evolution have not brought yet any conclusive evidence on the nature and location of primitive matter in the Solar System, preventing a clear understanding of its early stages.

Libourel, G.↗
NASA NTRS2017

Experimental Study into the Stability of Whitlockite in Basaltic Magmas

Apatite Ca5(PO4)3(F,Cl,OH), merrillite Ca18Na2Mg2(PO4)14, and whitlockite Ca9(Mg,Fe2+)(PO4)6[PO3(OH)] are the primary phosphate minerals found in most planetary materials including rocks from Earth, Moon, Mars, and asteroids [1-2]. For many years, the terms merrillite and whitlockite have been used interchangeably in the meteorite literature. Much of the confusion regarding the relationship between terrestrial and extraterrestrial "whitlockite" is based on the presence or absence of hydrogen in the mineral structure. Whitlockite has approximately 8500 ppm H2O, and the term "merrillite" has been adopted to identify the hydrogen-free form of whitlockite [2]. The atomic structures of merrillite and whitlockite were examined in detail by Hughes et al. [3-4]. On Earth, whitlockite has been found in rocks from evolved pegmatitic systems [2-4] and in some mantle rocks [e.g., 5]. Furthermore, terrestrial whitlockite has been shown to have some merrillite component [4]. For the meteoritic and lunar materials that have been investigated, merrillite appears to be far more common than whitlockite, and it has been proposed that the whitlockite component is unique to terrestrial samples [4]. There are some reports of "whitlockite" in the meteorite literature; however, these likely represent misidentifications of merrillite because there have been no reports of extraterrestrial whitlockite that have been verified through crystal structural studies or analyzed for their H contents. Hughes et al. [3] reported the atomic arrangement of lunar merrillite and demonstrated that the phase is similar to meteoritic merrillite and, predictably, devoid of hydrogen. In a follow-up study, Hughes et al. [4] reported the atomic arrangements of two natural samples of whitlockite, one synthetic whitlockite, and samples of synthetic whitlockite that were heated at 500degC and 1050degC for 24 h. The crystal chemistry and crystal structures of the phases were compared, and it was discovered that the latter treatment resulted in the dehydrogenation of whitlockite to form merrillite. The presence of merrillite vs. whitlockite was widely thought to serve as an indication that magmas were anhydrous [e.g., 6-7]. However, McCubbin et al., [8] determined that merrillite in the martian meteorite Shergotty had no discernible whitlockite component despite its coexistence with OH-rich apatite. Consequently, McCubbin et al., (2014) speculated that the absence of a whitlockite component in Shergotty merrillite and other planetary merrillites may be a consequence of the limited thermal stability of H in whitlockite (stable only at T less than1050degC), which would prohibit merrillite-whitlockite solid-solution at high temperatures. In the present study, we have aimed to test this hypothesis experimentally by examining the stability of whitlockite in basaltic magmas at 1.2 GPa and a temperature range of -1000- 1300degC.

McCubbin, F. M.↗
NASA NTRSDate not supplied

Assessing the Oxygen Permeability of Candidate Asteroid Sample Containers With Optochemical Sensors

The Astromaterials Acquisition and Curation Office at NASA Johnson Space Center currently curates 500 mg (10%) of carbonaceous asteroid Ryugu regolith collected by the Japan Aerospace and Exploration Agency’s Hayabusa II spacecraft and returned to Earth in 2021. In September 2023, NASA’s OSIRIS-REx spacecraft returned at least 70 grams of regolith collected from the surface of Carbonaceous Asteroid Bennu. These new astromaterials collections are stored and handled in gloveboxes and desiccators that are continuously purged with ultrapure nitrogen in order to minimize contamination and alteration of extraterrestrial samples from terrestrial environments, e.g., reaction with terrestrial oxygen and water. Ito et al. have previously reported on the development of containers to transport samples between facilities in inert, sealed environments; Hayabusa2 samples allocated to investigators by JAXA’s Extraterrestrial Sample Curation Center (ESCuC) are shipped in these Facility-to-Facility Transfer Containers (FFTCs). NASA curation has also been investigating sealed containers for storage, transportation, and allocation of Bennu and Ryugu regolith in sealed anoxic environments. In order to assess the ability of candidate sample containers to maintain nitrogen environments, we have utilized optochemical sensors to measure trace oxygen levels within sealed volumes.

C J Snead↗
NASA NTRS1991

Terrestrial production vs. extraterrestrial delivery of prebiotic organics to the early Earth

A comprehensive treatment of comet/asteroid interaction with the atmosphere, ensuring surface impact, and resulting organic pyrolysis is required to determine whether more than a negligible fraction of the organics in incident comets and asteroids actually survived collision with Earth. Results of such an investigation, using a smoothed particle hydrodynamic simulation of cometary and asteroidal impacts into both oceans and rock, demonstrate that organics will not survive impacts at velocities approx. greater than 10 km s(exp -1), and that even comets and asteroids as small as 100m in radius cannot be aerobraked to below this velocity in 1 bar atmospheres. However, for plausible dense (10 bar CO2) early atmospheres, there will be sufficient aerobraking during atmospheric passage for some organics to survive the ensuing impact. Combining these results with analytical fits to the lunar impact record shows that 4.5 Gyr ago Earth was accreting at least approx. 10(exp 6) kg yr(exp 1) of intact cometary organics, a flux which thereafter declined with a approx. 100 Myr half-life. The extent to which this influx was augmented by asteroid impacts, as well as the effect of more careful modelling of a variety of conservative approximations, is currently being quantified. These results may be placed in context by comparison with in situ organic production from a variety of terrestrial energy sources, as well as organic delivery by interplanetary dust. Which source dominated the early terrestrial prebiotic inventory is found to depend on the nature of the early terrestrial atmosphere. However, there is an intriguing symmetry: it is exactly those dense CO2 atmospheres where in situ atmospheric production of organic molecules should be the most difficult, in which intact cometary organics would be delivered in large amounts.

Chyba, C. F.↗
NASA NTRS1990

The Telecommunications and Data Acquisition Report

Archival reports are given on developments in programs managed by JPL's Office of Telecommunications and Data Acquisition (TDA), including space communications, radio navigation, radio science, ground-based radio and radar astronomy, and the Deep Space Network (DSN) and its associated Ground Communications Facility (GCF) in planning, supporting research and technology, implementation, and operations. Also included is TDA-funded activity at JPL on data and information systems and reimbursable DSN work performed for other space agencies through NASA. In the search for extraterrestrial intelligence (SETI), implementation and operations for searching the microwave spectrum are reported. Use of the Goldstone Solar System Radar for scientific exploration of the planets, their rings and satellites, asteroids, and comets are discussed.

Posner, E. C.↗
NASA NTRS2015

Cost-Effective Icy Bodies Exploration using Small Satellite Missions

It has long been known that Saturn's moon Enceladus is expelling water-rich plumes into space, providing passing spacecraft with a window into what is hidden underneath its frozen crust. Recent discoveries indicate that similar events could also occur on other bodies in the solar system, such as Jupiter's moon Europa and the dwarf planet Ceres in the asteroid belt. These plumes provide a possible giant leap forward in the search for organics and assessing habitability beyond Earth, stepping stones toward the long-term goal of finding extraterrestrial life. The United States Congress recently requested mission designs to Europa, to fit within a cost cap of $1B, much less than previous mission designs' estimates. Here, innovative cost-effective small spacecraft designs for the deep-space exploration of these icy worlds, using new and emerging enabling technologies, and how to explore the outer solar system on a budget below the cost horizon of a flagship mission, are investigated. Science requirements, instruments selection, rendezvous trajectories, and spacecraft designs are some topics detailed. The mission concepts revolve around a comparably small-sized and low-cost Plume Chaser spacecraft, instrumented to characterize the vapor constituents encountered on its trajectory. In the event that a plume is not encountered, an ejecta plume can be artificially created by a companion spacecraft, the Plume Maker, on the target body at a location timed with the passage of the Plume Chaser spacecraft. Especially in the case of Ceres, such a mission could be a great complimentary mission to Dawn, as well as a possible future Europa Clipper mission. The comparably small volume of the spacecraft enables a launch to GTO as a secondary payload, providing multiple launch opportunities per year. Plume Maker's design is nearly identical to the Plume Chaser, and fits within the constraints for a secondary payload launch. The cost-effectiveness of small spacecraft missions enables the exploration of multiple solar system bodies in reasonable timeframes despite budgetary constraints, with only minor adaptations. The work presented here is a summary of concepts targeting icy bodies, such as Europa and Ceres, which have been developed over the last year at NASA Ames Research Center's Mission Design Division. The platforms detailed in this work are also applicable to the cost-effective exploration of many other small icy bodies in the solar system.

Mission Design↗
NASA NTRS2013

Dawn Orbit Determination Team : Trajectory Modeling and Reconstruction Processes at Vesta

The NASA Dawn spacecraft was launched on September 27, 2007 on a mission to study the asteroid belt's two largest objects, Vesta and Ceres. It is the first deep space orbiting mission to demonstrate solar-electric ion propulsion, providing the necessary delta-V to enable capture and escape from two extraterrestrial bodies. At this time, Dawn has completed its science campaign at Vesta and is currently on its journey to Ceres, where it will arrive in mid-2015. The spacecraft spent over a year in orbit around Vesta from July 2011 through August 2012, capturing science data during four dedicated orbit phases. In order to maintain the reference orbits necessary for science and enable the transfers between those orbits, precise and timely orbit determination was required. The constraints associated with low-thrust ion propulsion coupled with the relatively unknown a priori gravity and rotation models for Vesta presented unique challenges for the Dawn orbit determination team. While [1] discusses the prediction performance of the orbit determination products, this paper discusses the dynamics models, filter configuration, and data processing implemented to deliver a rapid orbit determination capability to the Dawn project.

Vesta↗
NASA NTRS2015

Advances in Astromaterials Curation: Supporting Future Sample Return Missions

NASA's Astromaterials, curated at the Johnson Space Center in Houston, are the most extensive, best-documented, and leastcontaminated extraterrestrial samples that are provided to the worldwide research community. These samples include lunar samples from the Apollo missions, meteorites collected over nearly 40 years of expeditions to Antarctica (providing samples of dozens of asteroid bodies, the Moon, and Mars), Genesis solar wind samples, cosmic dust collected by NASA's high altitude airplanes, Comet Wild 2 and interstellar dust samples from the Stardust mission, and asteroid samples from JAXA's Hayabusa mission. A full account of NASA's curation efforts for these collections is provided by Allen, et al [1]. On average, we annually allocate about 1500 individual samples from NASA's astromaterials collections to hundreds of researchers from around the world, including graduate students and post-doctoral scientists; our allocation rate has roughly doubled over the past 10 years. The curation protocols developed for the lunar samples returned from the Apollo missions remain relevant and are adapted to new and future missions. Several lessons from the Apollo missions, including the need for early involvement of curation scientists in mission planning [1], have been applied to all subsequent sample return campaigns. From the 2013 National Academy of Sciences report [2]: "Curation is the critical interface between sample return missions and laboratory research. Proper curation has maintained the scientific integrity and utility of the Apollo, Antarctic meteorite, and cosmic dust collections for decades. Each of these collections continues to yield important new science. In the past decade, new state-of-the-art curatorial facilities for the Genesis and Stardust missions were key to the scientific breakthroughs provided by these missions." The results speak for themselves: research on NASA's astromaterials result in hundreds of papers annually, yield fundamental discoveries about the evolution of the solar system (e.g. [3] and references contained therein), and serve the global scientific community as ground truth for current and planned missions such as NASA's Dawn mission to Vesta and Ceres, and the future OSIRIS REx mission to asteroid Bennu [1,3]

Evans, C. A.↗
NASA NTRS2020

Extraterrestrial Organic Compounds and Cyanide in the CM2 Carbonaceous Chondrites Aguas Zarcas and Murchison

Evaluating the water-soluble organic composition of carbonaceous chondrites is key to understanding the inventory of organic matter present at the origins of the solar system and the subsequent processes that took place inside asteroid parent bodies. Here, we present a side-by-side analysis and comparison of the abundance and molecular distribution of aliphatic amines, aldehydes, ketones, mono- and dicarboxylic acids, and free and acid-releasable cyanide species in the CM2 chondrites Aguas Zarcas and Murchison. The Aguas Zarcas meteorite is a recent fall that occurred in central Costa Rica and constitutes the largest recovered mass of a CM-type meteorite after Murchison. The overall content of organic species we investigated was systematically higher in Murchison than in Aguas Zarcas. Similar to previous meteoritic organic studies, carboxylic acids were one to two orders of magnitude more abundant than other soluble organic compound classes investigated in both meteorite samples. We did not identify free cyanide in Aguas Zarcas and Murchison; however, cyanide species analyzed after acid-digestion of the water-extracted meteorite mineral matrix were detected and were quantified at slightly higher abundances in Aguas Zarcas compared to Murchison. Although there were differences in the total abundances of specific compound classes, these two carbonaceous chondrites showed similar isomeric distributions of aliphatic amines and carboxylic acids, with common traits such as a complete suite of structural isomers that decreases in concentration with increasing molecular weight. These observations agree with their petrologic CM type-2 classification, suggesting that these meteorites experienced similar organic formation processes and/or conditions during parent body aqueous alteration.

Jose Carlos Aponte Silva↗