Sample Return Research Articles

Preservation of Microorganisms (Chroococcidiopsis sp. 029) in Salt Minerals under Low Atmospheric Pressure: Application to Life Detection on Mars

Salt minerals on Mars represent a promising target for investigating potential past surface and subsurface life. Terrestrial salt minerals have been shown to incorporate microorganisms within crystals. However, the effect of Mars’s low atmospheric pressure on the preservation of microorganisms in salt minerals during their formation remains unclear. Here we investigated the interactions between microorganisms (Chroococcidiopsis sp. 029) and crystals of halite (NaCl), epsomite (MgSO4·7H2O), and gypsum (CaSO4·2H2O) during the rapid evaporation of brines under simulated Martian atmospheric pressure. Parallel experiments were conducted under terrestrial pressure for comparison. Halite, epsomite, and gypsum formed under both terrestrial and low-pressure conditions, though crystal morphologies varied depending on the pressure. Microorganisms were identified within fluid inclusions or as solid inclusions in the crystal matrix. Halite crystals exhibited a greater propensity to incorporate cells under low pressure compared to terrestrial pressure, while the entrapment of cells in epsomite was similar under both conditions. In contrast, significantly fewer cells were trapped in gypsum crystals under low pressure. The results demonstrate the feasibility of cell entrapment in salt minerals formed by rapid evaporation under low-pressure conditions on Mars, and atmospheric pressure exerts distinct influences on different types of salts. The variation in fluid inclusion size in halite under different pressures even shows promise as a possible paleobarometer. Our findings suggest that halite is the most promising candidate for preserving potential Martian life and could be an excellent target for future Mars sample return missions.

Operational considerations for approximating molecular assembly by Fourier transform mass spectrometry

Some of the most common life detection techniques for planetary exploration focus on organic molecule characterization, but life on other planets may not chemically resemble that found on Earth. Therefore, an agnostic detection system of signs of life (biosignatures) is essential. Assembly Theory (AT) is a conceptual tool for understanding evolution and object formation that has been useful in developing an approach to quantify molecular complexity via the Molecular Assembly index, which when combined with abundance, allows the total assembly number of a sample to be calculated. Because AT makes no assumptions about the chemistry of life, it is an agnostic tool that identifies molecular structures that are probabilistically more likely to have arisen via selection and therefore biological processes. AT uses graph theory to quantify molecular complexity by finding the shortest sequence of joining operations (e.g., chemical bonds) required to build a compound from a set of starting materials allowing recursive reuse of units or fragments. For molecules, this number of steps is the MA value. We explore the use of Fourier transform (i.e., Orbitrap) mass spectrometry for approximating MA by quantifying how a molecule breaks apart into fragments. We analyze amino acid and nucleoside standards individually and as mixtures, as well as amino acids from naturally occurring biological and meteoritic sources. Aside from sample type, we evaluate the effect of analyte concentration and fragmentation energies on the generated MA value. Additionally, an older Orbitrap model similar to flight prototype instrumentation, was tested. The raw mass spectrometry data was compared with two different MA processing algorithms - one that uses the parent molecule spectrum and molecular weight (recursive) and one that does not (non-recursive). Concentration, fragmentation energy, and sample type all influence the raw mass spectra. However, the recursive algorithm reports MA estimates that are more consistent across sample types, concentrations, and fragmentation energies. We discuss instrument requirements for approximating MA that can be applied to future flight and sample return missions.

A novel pattern language method for tradespace exploration: application to space mission architecting

With the growing complexity of systems across diverse domains, key challenges emerge in simultaneously designing networks and their underlying infrastructure, requiring resolution at concept stage. In space mission design, technological advancements and ambitious goals enable numerous mission architecture concepts due to diverse material flow options. Current design support tools function either after the initial concept design, or tend to rapidly converge toward point solutions, limiting the solution space. We introduce a digital tool for early-stage concept design, capable of generating, evaluating, and visualising a wide range of user-defined architectural options. It utilises a pattern language for space missions, incorporating building blocks like ‘launch’ or ‘electrolysis’. Validation with historic missions showcase the tool automatically identifies all four main mission architectures considered during the Apollo design and more, and accurately recommending the Lunar Orbit Rendezvous architecture which was actually selected. Predicted masses, informing costs, vary by 15% and duration by 30% from actual values, which is within expectations. Identifying missions and leveraging expert knowledge is also demonstrated in the Mars Sample Return case. This approach can help minimise the risk of overlooking effective mission concepts early on. Furthermore, the method is applicable in other domains facing concurrent infrastructure and logistics design challenges.

LIBS plasma diagnostics with SuperCam on Mars: Implications for quantification of elemental abundances

The Perseverance rover landed in Jezero Crater, Mars, in 2021 to explore an ancient delta for signs of past life and collect samples for a future Mars Sample Return Mission. SuperCam, onboard Perseverance, uses Laser Induced Breakdown Spectroscopy (LIBS) to quantify the elements in the rocks/soils encountered along the rover's traverse. LIBS is desirable for planetary science missions because of its effectiveness at a distance and with different target types (rock, soil, etc). However, decreased laser irradiance with distance and changing coupling efficiency in different targets could cause the physical conditions of the plasma plume to vary, with important implications for SuperCam's elemental calibration. This study examines the characteristics of laser-induced plasmas on Mars by estimating apparent temperature via the multiline Boltzmann plot method and electron density using Stark broadening of the H-α line. We find that apparent plasma temperatures do not decrease with distance or vary systematically with target type (rock vs soil). The variability in plasma temperatures seen on Mars is fully represented in the laboratory dataset used for SuperCam's elemental calibration, which suggests that our elemental calibration is likely robust against observed changes in apparent plasma temperature. These results imply that SuperCam can make reliable LIBS observations to at least 8 m. Estimated electron density is 1.4× higher in soils than rock targets, which is likely related to the dependence of the H-α line on topographic relief, a poorly understood mechanism which contributes to the difficulty of quantifying hydrogen abundance in Mars spectra.

Orientale Basin as a Guide for Identifying Lunar Basin Datable Impact Melt and Assessing Impact Melt Differentiation

Two fundamental questions face lunar scientists: (1) What is the absolute age of each lunar impact basin and thus the early impact flux curve? (2) To what degree did basin impact melt seas undergo differentiation? We compiled a 1:200,000-scale geological map of the lunar Orientale basin, focusing on identifying the most widespread and accessible occurrences of impact melt deposits from the basin-forming impact to help guide sample-return missions to Orientale and especially to other undated lunar basins using the identification and interpretation strategies for Orientale. We assess the size of craters excavating through basalt cap rock that may have exhumed datable basin impact melt, and we assess the possibility of impact melt sampling and melt differentiation for the large complex crater Maunder. We also provide guidance for distinguishing impact melt produced by larger complex craters from excavated basin melt and determining whether such craters may have also sampled through the entire melt deposit. Our analysis finds six such sites that are predicted to have the same age—that of the Orientale-forming event—and provides guidance for assessing possible melt differentiation. Future missions could collect samples from these sites for in situ age dating and petrologic assessment and/or for return to Earth and subsequent age dating and analysis. By sampling and dating impact melt of known provenance from the Moon’s dozens of large basins, future work can anchor the chronostratigraphy of the Moon’s formative years. Such information could be scaled to infer Earth’s large impactor flux around the time of life’s first emergence.

Diagenetic History and Biosignature Preservation Potential of Fine‐Grained Rocks at Hogwallow Flats, Jezero Crater, Mars

AbstractThe Mars 2020 Perseverance rover discovered fine‐grained clastic sedimentary rocks in the “Hogwallow Flats” member of the “Shenandoah” formation at Jezero crater, Mars. The Hogwallow Flats member shows evidence of multiple phases of diagenesis including Fe/Mg‐sulfate‐rich (20–30 wt. %) outcrop transitioning downward into red‐purple‐gray mottled outcrop, Fe/Mg clay minerals and oxides, putative concretions, occasional Ca sulfate‐filled fractures, and variable redox state over small (cm) spatial scales. This work uses Mastcam‐Z and SuperCam instrument data to characterize and interpret the sedimentary facies, mineralogy and diagenetic features of the Hogwallow Flats member. The lateral continuity of bedrock similar in tone and morphology to Hogwallow Flats that occurs over several km within the western Jezero sedimentary fan suggests widespread deposition in a lacustrine or alluvial floodplain setting. Following deposition, sediments interacted with multiple fluids of variable redox state and salinity under habitable conditions. Three drilled sample cores were collected from this interval of the Shenandoah formation as part of the Mars Sample Return campaign. These samples have very high potential to preserve organic compounds and biosignatures. Drill cores may partially include dark‐toned mottled outcrop that lies directly below light‐toned, sulfate‐cemented outcrop. This facies may represent some of the least oxidized material observed at this interval of the Shenandoah formation. This work reconstructs the diagenetic history of the Hogwallow Flats member and discusses implications for biosignature preservation in rock samples for possible return to Earth.

Curation and classification procedures for the UK Antarctic meteorite collection

AbstractThe field of advanced curation is important for existing astromaterials collections, which includes samples returned by space missions, and meteorites and cosmic dust samples that have been recovered from here on Earth. In order to maximize the scientific return of the samples, contamination needs to be minimized at all stages of sample collection, preliminary examination, classification, and curation. Utilizing best practice methods, a detailed acquisition and curation plan was implemented during the UK's first two expeditions to collect Antarctic meteorites from two new blue icefields, Hutchison Icefields and Outer Recovery Icefields. This article documents the design and execution of the procedures used during the project's curation and classification processes. It describes two case studies showing the processes applied to the recovered meteorites, and reviews our experiences and lessons learned for the future.

The search for life signatures on Mars by the Tianwen-3 Mars sample return mission.

We present the proposed strategic study, 'Integrated elements for Martian life signature exploration', to support the sampling and identification of any potential biosignatures in compliance with the engineering constraints of the Tianwen-3 mission.

Magnetite Survivability and Non‐Stoichiometric Magnetite Formation in Presence of Oxyhalogen Brines on Mars

AbstractThe mixed Fe(II)/Fe(III) mineral magnetite [Fe3O4] of various stoichiometric and non‐stoichiometric compositions have been reported in Martian soils and rocks by several rover missions. Magnetite is an important paleomagnetic indicator mineral and can serve as a ‘biogeobattery’ as a consequence of its magnetic properties and the mixed valence state of iron in its structure. Here, we assess the extent of oxidative weathering of magnetite in presence of chlorate and bromate containing solutions that are likely important oxidants on Mars. Oxyhalogen species, chlorate and bromate, produced non‐stoichiometric magnetite [Fe(II)/Fe(III) < 0.5] in Mars‐relevant, near‐neutral pH fluids; no other ferric minerals were produced. The same results were observed in highly acidic fluids with or without oxyhalogens. Owing to its resistance to extensive oxidation, magnetite can serve as an important archive of geochemical, paleomagnetic, and astrobiological information in samples that will be returned by the Mars Sample Return mission.

The Production Population of Impact Craters in the Chang’E-6 Landing Mare

The Chang’E-6 mission accomplished the first sample return from the lunar farside. Earlier crater population measurements estimated the model age of the landing mare to range from the Eratosthenian to Late Imbrian, both of which are underrepresented by earlier returned samples. Establishing a new calibration point for lunar impact flux based on isotopic ages of the samples is promising, but the representative crater density for the landing mare (i.e., spatial density of craters with D ≥ 1 km; N (1)) is equally important for this purpose, which lacks good constraints. After excluding the effects of background secondaries, crater equilibrium, and observational uncertainties on crater statistics, this work extracts production populations in different diameter ranges (∼200 m–2 km) from multiple subareas of the landing mare. Cross-validation of the production populations verifies that N (1) derived from direct measurements of craters with D ≥ 1 km in sketched areas are reliable, which is (2.01 ± 0.90) × 10−3 and (6.05 ± 2.71) × 10−3 km2 for the western and eastern mare, respectively.

Space exploration in China

Abstract In the past 20 years, China has implemented Manned Space Engineering, Lunar and Mars exploration missions, becoming an active participant in human space travel and exploration. So far China has established its Space Station in 2022, continuing to carry out large-scale space science research for the next 10-15 years. China has successfully achieved the soft landing on the lunar, far side of the Moon and on the Mars surface, obtained 1.73 kg of lunar sample, and will also implement the lunar Antarctic sample return and Mars sample return mission later. The exploration missions for the asteroid and Jupiter system are being prepared. Overall the future science exportations and collaborations between human and robot, as well as the utilisation of extraterrestrial resources will become the new development focus. Chinese scientists eagerly look forward to close international collaboration.

Organic Carbon and Ca‐Rich Carbonate Detections in Soils of the Northern Plains, Mars: Evaluation of Unreported Data From the Mars Phoenix Scout's Thermal Evolved Gas Analyzer (TEGA)

AbstractThe Thermal Evolved Gas Analyzer (TEGA) analysis of surface and icy subsurface Phoenix landing site soils consisted of low (300–700°C) and high (>700°C) temperature CO2 evolutions that were attributed to organic carbon (83–1,484 μgC/g) and Ca‐rich carbonate (1.1–2.6 wt.%). Total carbon abundances ranged from 1,143 to 4,905 µgC/g, which is the highest soil carbon concentration so far detected on Mars. Low temperature CO2 was attributed to oxidized organic C (e.g., oxalates, acetates), while hydrocarbon combustion was indicated in two soils by the detection of coevolved CO2 and O2 (perchlorate). Combustion reactions may have prevented the detection of hydrocarbon masses in the Phoenix landing site soils. Organic C was likely derived from meteoritic and igneous/hydrothermal sources, but microbiological sources cannot be excluded. CO2 evolved at high temperatures was consistent with Ca‐rich carbonate along with possible minor contributions from macromolecular organic carbon and mineral/glass vesicle CO2. Carbon detected in the Phoenix landing site soil and other landing site soils and sands (e.g., Gale/Jezero craters) would be consistent with global organic C and carbonate in soils and sand across Mars. However, oxidizing water thin films derived from the near‐surface ice in the Phoenix soils favor Ca‐carbonate over Fe‐carbonate, which is likely more stable in the ice‐free regions of Mars (e.g., Gale/Jezero craters). The global carbon budget on Mars inferred from these results emphasizes that Mars Sample Return should yield carbon bearing soil/rock that would allow the identification of the origin of carbon and any possible connections to ancient martian microbiology.

A High-Reliability Photoelectric Detection System for Mars Sample Return’s Orbiting Sample

The Mars Sample Return campaign is an endeavor of unprecedented technological complexity and coordination that attempts to answer fundamental questions about the habitability of Mars by returning the first samples of Martian material to Earth for analysis. The third mission in the campaign consists of the NASA-provided Capture, Containment, and Return System (CCRS) onboard the European Space Agency’s Earth Return Orbiter, which will retrieve the Orbiting Sample (OS) container from its orbit around Mars. Retrieving a passive sample container from a planetary orbit has never been attempted by any spacecraft and requires the development of new technology to succeed in this ambitious task. This paper introduces the high-reliability Capture Sensor Suite (CSS), a novel optical detection system that provides CCRS with the capability to autonomously detect the OS as it is captured. This article will discuss the challenges and requirements for the fault-tolerant design of the CSS.

Optimization of MMX relative quasi-satellite transfer trajectories using primer vector theory

Quasi-satellite orbits (QSO) are stable retrograde parking orbits around Phobos that are currently being considered for JAXA’s upcoming robotic sample return mission Maritan Moons Exploration (MMX). During the proximity operations of MMX, the spacecraft inserted in a high altitude QSO will gradually descend to lower altitude QSOs with suitable transfer and station-keeping techniques between different relative QSOs. Preliminary analysis of two-impulsive planar transfers between relative retrograde orbits utilizing the bifurcated QSOs families is studied to estimate the ΔV costs and time of flights of the transfers. In this paper, differently from previous works, we utilize the initial guesses found through the preliminary results that provide two-impulsive transfer ΔV execution points and optimize the transfers between relative QSOs around Phobos. Primer vector theory is applied to investigate the primer vector of the MMX transfer trajectories to evaluate whether intermediate maneuver or initial/final coasting times along the trajectories can minimize the total ΔV cost between the transfers. Based on the primer vector analysis of the impulse transfer trajectories, it is found that departing and arriving at the same periphobian sides with an additional mid-course impulse results in the optimal impulse solution.

Quantitative analysis of spectral properties and composition of primitive achondrites (acapulcoites, lodranites and winonaites)

The establishment of robust meteorite-asteroid links has been a major focus of planetary exploration, and a major driver of asteroid sample return missions. Reflectance spectroscopy has been shown to be a powerful tool for this purpose. For the meteorites dominated by silicate minerals, quantitative analysis of spectral absorption features caused by the Fe2+-bearing minerals (mainly olivine and pyroxene) is a common method to determine mafic silicate mineralogy and end member abundances, and establish the relationship between them and possible parent bodies. In this study, the reflectance spectra of 22 primitive achondrites (acapulcoites, lodranites and winonaites) from NASA RELAB database were analyzed to determine their positions in the plot of the band area ratio (BAR) and 1 μm band center (Band I center). We found that Band I center and BAR of acapulcoites and lodranites are in roughly the same range. Acapulcoite-lodranite partially overlap with the field of H chondrites in the plot of the BAR and Band I center. This overlap means that spectral calibrations (also referred to as mineralogical formulas) based on the two types of meteorites needs to be applied with caution. The 2 μm band center of acapulcoite–lodranite is significantly lower than that of H chondrites, which is consistent with the conclusion of previous studies and provides a means to separate these two groups. In addition, the choice of spectral parameter analysis techniques may be a potential error source in similar studies. We provide generalized spectral fields of primitive achondrites in the plot of the BAR and Band I center derived from two widely used technologies.

Nature of the lunar far-side samples returned by the Chang'E-6 mission.

The Chang'E-6 (CE-6) mission successfully achieved return of the first samples from the far side of the Moon. The sampling site of CE-6 is located in the South Pole-Aitken (SPA) basin-the largest, deepest and oldest impact basin on the Moon. The 1935.3g of CE-6 lunar samples exhibit distinct characteristics compared with previous lunar samples. This study analyses the physical, mineralogical, petrographic and geochemical properties of CE-6 lunar scooped samples. The CE-6 soil has a significantly lower bulk density (0.983g/cm3) and true density (3.035g/cm3) than the Chang'E-5 (CE-5) samples. The grain size of the CE-6 soil exhibits a bimodal distribution, indicating a mixture of different compositions. Mineralogically, the CE-6 soil consists of 32.6% plagioclase (anorthite and bytownite), 19.7% augite, 10% pigeonite and 3.6% orthopyroxene, and with low content of olivine (0.5%) but high content of amorphous glass (29.4%). Geochemically, the bulk composition of CE-6 soil is rich in Al2O3 (14%) and CaO (12%) but low in FeO (17%), and trace elements of CE-6 soil such as K (∼630ppm), U (0.26ppm), Th (0.92ppm) and rare-earth elements are significantly lower than those of the lunar soils within the Procellarum KREEP Terrane. The local basalts are characterized by low-Ti (TiO2, 5.08%), low-Al (Al2O3 9.85%) and low-K (∼830ppm), features suggesting that the CE-6 soil is a mixture of local basalts and non-basaltic ejecta. The returned CE-6 sample contains diverse lithic fragments, including local mare basalt, breccia, agglutinate, glasses and leucocrate. These local mare basalts document the volcanic history of the lunar far side, while the non-basaltic fragments may offer critical insights into the lunar highland crust, SPA impact melts and potentially the deep lunar mantle, making these samples highly significant for scientific research.

Exploring the dielectric loss of Martian regolith in the frequency domain using Zhurong radar data

Martian regolith is one of the primary science objectives of Mars exploration missions. The Rover Penetrating Radar carried by Zhurong rover allows for high-resolution subsurface imaging and in-situ measurements of Martian regolith dielectric properties, which are crucial to advance our understanding of Martian geology and hydrological evolution. While earlier studies have derived dielectric constants for the shallow subsurface, further characterization of subsurface materials requires the determination of attenuation properties. In this study, we applied the centroid-frequency shift method to explore the attenuation property of the Martian regolith in the frequency domain. Lateral attenuation variation was analyzed in detail by integrating subsurface radargram and navigation terrain images. The results show that, within a depth of ∼4 m, the attenuation of radar signal for Zhurong subsurface material is equal to a loss tangent of 0.0079, with a standard deviation of 0.001. Based on the loss tangent value, dielectric permittivity and ground characterization, we preclude the possibility that the regolith is predominantly igneous materials. The lateral variation of the attenuation property could likely be attributed to changes in the proportion of duricrusts, which are heterogeneously distributed along the rover traverse. Our findings offer valuable information for understanding the Martian regolith and its evolution, serving as a important reference for future Mars sample return missions.

Geophysical Observations of the 2023 September 24 OSIRIS-REx Sample Return Capsule Reentry

Sample return capsules (SRCs) entering Earth’s atmosphere at hypervelocity from interplanetary space are a valuable resource for studying meteor phenomena. The 2023 September 24 arrival of the Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer SRC provided an unprecedented chance for geophysical observations of a well-characterized source with known parameters, including timing and trajectory. A collaborative effort involving researchers from 16 institutions executed a carefully planned geophysical observational campaign at strategically chosen locations, deploying over 400 ground-based sensors encompassing infrasound, seismic, distributed acoustic sensing, and Global Positioning System technologies. Additionally, balloons equipped with infrasound sensors were launched to capture signals at higher altitudes. This campaign (the largest of its kind so far) yielded a wealth of invaluable data anticipated to fuel scientific inquiry for years to come. The success of the observational campaign is evidenced by the near-universal detection of signals across instruments, both proximal and distal. This paper presents a comprehensive overview of the collective scientific effort, field deployment, and preliminary findings. The early findings have the potential to inform future space missions and terrestrial campaigns, contributing to our understanding of meteoroid interactions with planetary atmospheres. Furthermore, the data set collected during this campaign will improve entry and propagation models and augment the study of atmospheric dynamics and shock phenomena generated by meteoroids and similar sources.

Automated Identification of Outgassed Chemical Species Using Mass Spectrometry for Scientific Space Missions

Current and planned space exploration and life detection missions such as NASA Jet Propulsion Laboratory’s Mars 2020, Mars Sample Return, and Europa Clipper require record-low contamination levels. In this work, we develop a novel automated outgassing contamination species identification method using mass spectrometry data. Thanks to the existing knowledge of ASTM-E1559 and direct analysis in real-time mass spectrometry material testing methods, we improved species outgassing deconvolution and physical characterization techniques. We developed a brand-new combined approach that leverages both tests’ complementary insights into contaminants’ chemical identities. Namely, we rely on the Dromey–Foyster algorithm and the Seven Golden Rules of mass spectrometry analysis to narrow down the probable identified molecules by a factor of 10 compared to the sole use of ASTM-E1559. Furthermore, thanks to recent advances in machine learning spectral analysis, we developed a composite spectral score that ranks all candidate contaminants based on their similarity to the measurements. Ultimately, we validated an automated species identification algorithm on samples of NuSil CV4-2946, Dacron, and a spacecraft cable component. The techniques established in this work enable accurate estimations of outgassed contaminant species’ chemical structure, leading to a comprehensive understanding of the effects of outgassing on scientific objectives.

First direct detection of large polycyclic aromatic hydrocarbons on asteroid (162173) Ryugu samples: An interstellar heritage

AbstractPolycyclic aromatic hydrocarbons (PAHs) are considered major players in the physics and chemistry of star‐ and planet‐forming regions. The interstellar PAH hypothesis is based on our understanding of the origin of the aromatic infrared bands (AIBs), a set of bright emission features that are now the focus of observations by the James Webb telescope. While AIB carriers are expected to be large free PAHs (50 carbon atoms or more), laboratory analysis of primitive carbonaceous chondrites (CCs) has mainly revealed relatively small PAHs, up to 24 carbon atoms. In this study, we present a comprehensive analysis of aromatic species in bulk samples from the carbonaceous asteroid Ryugu using a surface mass spectrometry technique provided by two‐step laser desorption ionization. The resulting molecular distribution differs significantly from that obtained for a sample from the CC Orgueil, revealing aromatic species extending up to 61 carbon atoms. The species identified are composed of both peri‐condensed PAHs and non‐condensed aromatics. These results directly support the interstellar PAH hypothesis and open up new perspectives on the formation and evolution of organic matter in star‐forming regions and in the solar nebula.Key Points First direct detection of free aromatic species of large sizes with up to 61 carbon atoms in primitive extraterrestrial matter by applying a highly sensitive two‐step laser mass spectrometry analysis to grain samples from the carbonaceous asteroid Ryugu (Hayabusa2 mission). First direct support for the interstellar polycyclic aromatic hydrocarbon (PAH) hypothesis, according to which large free PAHs are responsible for the aromatic emission bands that are major infrared features currently observed by the James Webb Space Telescope. The large aromatic species detected are present in trace amounts and future research is needed to develop sensitive techniques for studying these compounds in sample return missions and meteorites.