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NASA NTRSDate not supplied

The Chemistry and Mineralogy of Mars Soils: A Tour of Landed Mission Results from the Last 45 years

Eight landed missions demonstrated that martian soils (defined as loose, unconsolidated surface material) consist of basaltic mineralogy, iron (hydr)oxides, amorphous material, sulfate, chloride, (per)chlorate, nitrate, carbonate, and possible organic C. The Viking Lander 1 and 2 (1976), Mars Pathfinder (1997), and Mars Exploration Rover (MER-A,B) (2004) missions determined that martian soil was similar at all landing sites by having mafic chemistry, high S (~ 7 wt.% SO3) and Cl (0.7 wt.%), and spectral detections of poorly crystalline and crystalline Fe-(hydr)oxide phases. The MER Mössbauer spectrometers detected Fe-bearing olivine and pyroxene along with magnetite, nano-phase Fe-oxides (npOx), hematite, and ferric sulfate. The 2008 Phoenix Lander instrumentation measured a soil pH of 7.7 and detected ~0.6 wt.% perchlorate, 3-5 wt.% Ca-rich carbonate and carbon (500 gC/g) consistent with oxidized organics and Fe-rich carbonate. The 2012 Mars Science Laboratory (MSL) rover (Gale Crater) through X-ray diffraction detected plagioclase feldspar, pyroxene, magnetite, hematite, anhydrite, and quartz, with the balance being composed of Si/Fe-containing amorphous (30 to 40 wt.%) material. MSL evolved gas analysis detected (per)chlorate (0.4 wt.% ClO4), nitrate (0.23 wt.%), along with minor Fe/Mg sulfate and oxidized organic C (~2000 gC/g). Limited pedogenesis may have occurred at the 2018 InSight landing site and in one Gusev Crater soil (MER-B) which have 3 to 10 cm-thick duricrust horizons consistent with atmospheric water vapor interactions with soil salts. Martian soil primary mineralogy was derived mostly from local rock (volcanic, sedimentary) that is largely basaltic planet wide. Secondary minerals [e.g., sulfate, chloride, perchlorate, nitrate, carbonate, Fe-(hydr)oxides] in martian soils formed from oxidative aqueous alteration processes and were likely derived from a combination of local sedimentary rock sources and the global bright dust. The Mars 2020 mission will collect soil for Earth return to enable a thorough assessment of the nature and origin of martian soil.

Mars↗
NASA NTRSDate not supplied

Assessing Organic Preservation and the Implications for Potential Biosignatures in the Bastide Member of the Séítah Formation, Jezero Crater

Introduction: Olivine has the highest CO2 trapping potential of ultramafic minerals, due to its rapid rate of dissolution and high percentage of divalent cations/unpolymerized silicate tetrahedra [1]. It generates divalent carbonates from CO2 and sequesters CO2 into the mineral matrix of the target lithology. The co-occurrence of olivine and carbonate within abraded targets from the Bastide Member of the Séítah Formation (Fm) of the Jezero crater floor [2] suggests the carbonation of olivine occurred within the mineral matrix hosted in a subsurface system. Hydrothermal origins for the subsurface system are hypothesized from orbital data [3]. This is supported by the detection of hydration features within the rock as well as the carbonate features are solely detected within the abrasion patch but not the rock’s surface. Organic preservation potential of abrasion patches: We incorporated the SHERLOC/WATSON results acquired from the Dourbes, Garde, and Quartier abrasion patches in the Séítah Fm to investigate the organomineral associations, and determine the biosignature preservation potential of these rocks. Dourbes is dominated by olivine and has minor amounts of carbonate, hydrated Ca-sulfate, and amorphous or microcrystalline silicate. Fluorescence features (330-340 nm) are detected in discrete locales and could be consistent with double ring aromatic organic molecules; yet, these features do not appear to be associated with an identified mineral phase. Dark subhedral to euhedral olivine grains within the Garde abrasion patch often co-occur with carbonate-consistent spectral signatures in all analyzed scans. The availability of Fe2+ is a known influence on olivine dissolution rates [1] and SuperCam estimates of the olivine composition (Forsterite-60 average for Sols 202-234) may thereby provide a constraint on the carbonation extent. Carbonated olivine phenocrysts within the matrix may be due to aqueous alteration, as the carbonation of nodules is consistent with observations in other hydrothermal systems and within Martian meteorites (ALH84001) [4]. In comparison, the Quartier abrasion patch represents an extensively altered endmember within the Bastide Member of the Séítah Fm. It contains a fluorescence doublet at 305/325 nm that coexists with multiple species of Na-sulfate and Mg-sulfate, Mg-carbonates, olivine [5]. Aqueous alteration and implications for habitability: The identification of primary and secondary mineral phases observed in the Bastide Member suggests the release of cations from primary ultramafic minerals through aqueous alteration. Within Garde, the carbonate detected appears to be Mg-rich and likely formed from the in situ alteration of Mg-rich olivine within the region as carbonate has only been detected within the rock via in situ analysis. Carbonates derived from abiotic and biotic reactions preserve biosignatures (i.e. indices of habitability) on Earth. The detected carbonate phase found in association with fluorescent features within the rock matrix may also indicate potential organic compounds preserved in a putative hydrothermal system. Fluorescent features (~330 nm) are unique to Garde and Dourbes, though they are co-located to carbonate signatures solely within Garde, and between the light toned minerals. Identification of these fluorescent features may be consistent with 1-2 ring aromatic compounds. The limit of detection for Raman is multiple orders of magnitude greater than the limit of detection required for fluorescence [6]. Implications for provenance: Hydrothermal systems represent disequilibrium chemical conditions that are hypothesized to have supported the emergence of life and also preserve ancient carbon within precipitated carbonates [7]. Hydrothermal system associated carbonates are capable of preserving biosignatures up to an estimated ~3.77 – 4.28 Gya [8]. Thus, carbonated olivine found within the Séítah Fm may represent a high-potential biosignature preserving environment on Mars. The formation of carbonates by an aqueous alteration process, such as carbonation of olivine is also consistent with hypotheses for carbonate within the greater regional-olivine bearing unit [2,3], which contains Garde, Dourbes, and Quartier. Acknowledgments: This work was carried out at the Jet Propulsion Laboratory, The California Institute of Technology under a contract from NASA. References: [1] Wood et al., (2019) ES&T, 6, 10. [2] Stack, K. et al., (2020) Space Sci Rev, 216, 127. [3] Tarnas, J. et al., (2021) JGR: Planets, 126, 11. [4] Steele et al., (2007) Meteorit. Planet. Sci., 42, 9. [5] Murphy, A.E. et al., (2022) LPSC [6] Bhartia et al., (2021) Space Sci Rev, 217, 58. [7] Luther (2021) GRL, 48, e2021GL094869. [8] Dodd et al., (2017) Nature, 543, 60-64

E L Cardarelli↗
NASA NTRSDate not supplied

Chemistry of Venus’ Recent Basalts as Clues to its Ancient Past

Perhaps the most important question about Venus is whether it ever had a hydrosphere: liquid water, oceans, and thus an environment suitable for life as we know it. The D/H of Venus’ atmosphere suggests extensive water loss, and climate models may be consistent with global oceans. Rocks dating from that epoch may be preserved in Venus’ tesserae (and especially Ishtar Terra) – inferred to of felsic or silicic rock, which would suggest abundant water. However, the exact elemental compositions of tesserae (silicic or not) will be difficult to retrieve and most of Venus’ surface is basalt flows and volcanic constructs, inferred to be much younger than the oceanic epoch. Remotely sensed data are (and will be) ambiguous about the specific rock types that make up tesserae, and lander spacecraft are almost certain (in the near term) to avoid the rough and precipitous topography of the tesserae and touch down instead on flat, safe basaltic plains or volcanic rises. ‘Recent’ basalts at Venus’ surface could preserve chemical tracers of an ancient aqueous past, if their source regions (material that was re-melted) had been affected by water. This scenario occurs on Earth in Island Arc Basalts (IAB), where their compositions are thought to reflect aqueous alteration of parental midocean ridge basalts (MORB) and incorporation of oceanic sediments. Ancient Venus might have supported plate tectonic and thus have had IAB equivalents; absent plate tectonics, basalt affected by aqueous alteration could have been cycled into its mantle by burial under thick sections of later basalt. Our purpose is to suggest specific chemical clues in current basalts that would permit recognition of those with a history of aqueous interactions from those that did not. We compare Earth’s Ocean Island Basalts (OIB) that involved little water with IAB that show chemical effects ascribable to water. It is not clear that Venus’ basalts can be mapped into terrestrial tectonic settings; however, it seems reasonable that aqueous geochemical processes could have (had) similar effects on both planets.

A H Treiman↗
NASA NTRSDate not supplied

High Resolution Imaging and Analysis of Terrestrial Impact Glass: Amorphous Materials, Phyllosilicates and Everything in Between

Introduction: Impact cratering is one of the most ubiquitous geologic processes shaping the surface of all solid bodies in our solar system. Impacts are also a major source of clay minerals, poorly crystalline clay-like phases and amorphous (i.e., lacking long-range atomic order) materials on Earth and Mars. Phyllosilicates and amorphous materials have consistently formed a major component (~20-70 wt%) of every single drilled rock and soil sample in Gale Crater on Mars, as determined by the CheMin instrument on Curiosity. The origin of the amorphous component is speculative, but could be primary impact or volcanic-produced glass(es) deposited via aeolian or fluvial processes, secondary aqueous alteration products or chemical precipitates; it is likely to be a combination of all three possibilities. Efforts to determine the composition of these materials across the rover’s traverse through Gale Crater are ongoing. Naturally occurring amorphous phases are found in a variety of environments on Earth, and terrestrial analogue studies may help shed light on how they may have formed on Mars. Primary and altered impact glass are likely widespread on Mars and may have contributed to the amorphous component found throughout Gale Crater. In its pristine, unaltered state, impact glass (i.e., melt glass) is considered amorphous. However, truly unaltered glass is rarely preserved in crater fill impactites as it quickly alters in the post-impact environ-ment, commonly forming a mixture of hydrated aluminosilicate phases whose structures are not always discernable at the microscale (i.e., they may be amorphous or contain short-range order). These phases are part of an incredibly complex group of materials; differences in their composition and crystalline structure (or lack thereof) and genetic relationship to the more well-crystalline clay minerals are often only discernable at the nanoscale, beyond the resolution of traditional X-ray diffractometers (XRD) and scanning electron microscopes/microprobes (SEM/EPMA) alone. In this contribution, we summarize recent results from ongoing characterization of clay minerals, poorly crystalline clay-like phases, and amorphous materials preserved in altered terrestrial impact glass from the Chicxulub (~66 Ma) and Ries (~15 Ma) impact structures. This work has been performed using a combination of high-resolution transmission electron microscopy (HR-TEM), SEM, microprobe/EPMA, Raman spectroscopy and XRD.

Impact crater↗
NASA NTRS2026

Hermal Evolution of Volatile-Rich Planetesimals: Implications for Lithological Diversity in Ryugu and CI Chondrites

Ryugu samples and CI chondrites record aqueous alteration processes in primitive, volatile-rich planetesimals and exhibit a wide range of lithologies defined by mineral assemblages and alteration degrees as proposed to be types I–VI in [4]. The similarity in lithological diversity and proportions between Ryugu and CIs suggests that they originated from parent bodies with comparable internal structures and thermal histories. However, the mechanism responsible for generating such lithological diversity within a single parent body remains unclear.

S Yamazaki↗
NASA NTRS1995

Development of CFC-Free Cleaning Processes at the NASA White Sands Test Facility

The NASA White Sands Test Facility (WSTF) is developing cleaning and verification processes to replace currently used chlorofluorocarbon-113- (CFC-113-) based processes. The processes being evaluated include both aqueous- and solvent-based techniques. The presentation will include the findings of investigations of aqueous cleaning and verification processes that are based on a draft of a proposed NASA Kennedy Space Center (KSC) cleaning procedure. Verification testing with known contaminants, such as hydraulic fluid and commonly used oils, established correlations between nonvolatile residue and CFC-113. Recoveries ranged from 35 to 60 percent of theoretical. WSTF is also investigating enhancements to aqueous sampling for organics and particulates. Although aqueous alternatives have been identified for several processes, a need still exists for nonaqueous solvent cleaning, such as the cleaning and cleanliness verification of gauges used for oxygen service. The cleaning effectiveness of tetrachloroethylene (PCE), trichloroethylene (TCE), ethanol, hydrochlorofluorocarbon-225 (HCFC-225), tert-butylmethylether, and n-Hexane was evaluated using aerospace gauges and precision instruments and then compared to the cleaning effectiveness of CFC-113. Solvents considered for use in oxygen systems were also tested for oxygen compatibility using high-pressure oxygen autoignition and liquid oxygen mechanical impact testing.

Beeson, Harold↗
NASA NTRS2009

Proceedings of the 40th Lunar and Planetary Science Conference

The 40th Lunar and Planetary Science Conference included sessions on: Phoenix: Exploration of the Martian Arctic; Origin and Early Evolution of the Moon; Comet Wild 2: Mineralogy and More; Astrobiology: Meteorites, Microbes, Hydrous Habitats, and Irradiated Ices; Phoenix: Soil, Chemistry, and Habitability; Planetary Differentiation; Presolar Grains: Structures and Origins; SPECIAL SESSION: Venus Atmosphere: Venus Express and Future Missions; Mars Polar Caps: Past and Present; SPECIAL SESSION: Lunar Missions: Results from Kaguya, Chang'e-1, and Chandrayaan-1, Part I; 5 Early Nebula Processes and Models; SPECIAL SESSION: Icy Satellites of Jupiter and Saturn: Cosmic Gymnasts; Mars: Ground Ice and Climate Change; SPECIAL SESSION: Lunar Missions: Results from Kaguya, Chang'e-1, and Chandrayaan-1, Part II; Chondrite Parent-Body Processes; SPECIAL SESSION: Icy Satellites of Jupiter and Saturn: Salubrious Surfaces; SNC Meteorites; Ancient Martian Crust: Primary Mineralogy and Aqueous Alteration; SPECIAL SESSION: Messenger at Mercury: A Global Perspective on the Innermost Planet; CAIs and Chondrules: Records of Early Solar System Processes; Small Bodies: Shapes of Things to Come; Sulfur on Mars: Rocks, Soils, and Cycling Processes; Mercury: Evolution and Tectonics; Venus Geology, Volcanism, Tectonics, and Resurfacing; Asteroid-Meteorite Connections; Impacts I: Models and Experiments; Solar Wind and Genesis: Measurements and Interpretation; Mars: Aqueous Processes; Magmatic Volatiles and Eruptive Conditions of Lunar Basalts; Comparative Planetology; Interstellar Matter: Origins and Relationships; Impacts II: Craters and Ejecta Mars: Tectonics and Dynamics; Mars Analogs I: Geological; Exploring the Diversity of Lunar Lithologies with Sample Analyses and Remote Sensing; Chondrite Accretion and Early History; Science Instruments for the Mars Science Lander; . Martian Gullies: Morphology and Origins; Mars: Dunes, Dust, and Wind; Mars: Volcanism; Early Solar System Chronology; Seek Out and Explore: Upcoming and Future Missions; Mars: Early History and Impact Processes; Mars Analogs II: Chemical and Spectral; Achondrites and their Parent Bodies; and Planning for Future Exploration of the Moon The poster sessions were: Lunar Missions: Results from Kaguya, Chang'e-1, and Chandrayaan-1; LRO and LCROSS; Geophysical Analysis of the Lunar Surface and Interior; Remote Observation and Geologic Mapping of the Lunar Surface; Lunar Spectroscopy; Venus Geology, Geophysics, Mapping, and Sampling; Planetary Differentiation; Bunburra and Buzzard Coulee: Recent Meteorite Falls; Meteorites: Terrestrial History; CAIs and Chondrules: Records of Early Solar System Processes; Volatile and Organic Compounds in Chondrites; Crashing Chondrites: Impact, Shock, and Melting; Ureilite Studies; Petrology and Mineralogy of the SNC Meteorites; Martian Meteorites; Phoenix Landing Site: Perchlorate and Other Tasty Treats; Mars Polar Atmospheres and Climate Modeling; Mars Polar Investigations; Mars Near-Surface Ice; Mars: A Volatile-Rich Planet; Mars: Geochemistry and Alteration Processes; Martian Phyllosilicates: Identification, Formation, and Alteration; Astrobiology; Instrument Concepts, Systems, and Probes for Investigating Rocks and Regolith; Seeing is Believing: UV, VIS, IR, X- and Gamma-Ray Camera and Spectrometer Instruments; Up Close and Personal: In Situ Analysis with Laser-Induced Breakdown Spectroscopy and Mass Spectrometry; Jupiter and Inscrutable Io; Tantalizing Titan; Enigmatic Enceladus and Intriguing Iapetus; Icy Satellites: Cryptic Craters; Icy Satellites: Gelid Geology/Geophysics; Icy Satellites: Cool Chemistry and Spectacular Spectroscopy; Asteroids and Comets; Comet Wild 2: Mineralogy and More; Hypervelocity Impacts: Stardust Models, LDEF, and ISPE; Presolar Grains; Early Nebular Processes: Models and Isotopes; Solar Wind and Genesis: Measurements and Interpretation; Education and Public Outreach; Mercury; Pursuing Lunar Exploration; Sources and Eruptionf Lunar Basalts; Chemical and Physical Properties of the Lunar Regolith; Lunar Dust and Transient Surface Phenomena; Lunar Databases and Data Restoration; Meteoritic Samples of the Moon; Chondrites, Their Clasts, and Alteration; Achondrites: Primitive and Not So Primitive; Iron Meteorites; Meteorite Methodology; Antarctic Micrometeorites; HEDs and Vesta; Dust Formation and Transformation; Interstellar Organic Matter; Early Solar System Chronology; Comparative Planetology; Impacts I: Models and Experiments; Impacts II: Craters and Ejecta; Mars: Volcanism; Mars: Tectonics and Dynamics; Martian Stratigraphy: Understanding the Geologic History of Mars Through the Sedimentary Rock Record; Mars: Valleys and Valley Networks; Mars: Aqueous Processes in Valles Marineris and the Southern Highlands; Mars: Aqueous Geomorphology; Martian Gullies: Morphology and Origins; Mars: Dunes, Dust, and Wind; Mars: Remote Sensing; Mars: Geologic Mapping, Photogrammetry, and Cratering; Martian Mineralogy: Constraints from Missions and Laboratory Investigations; Mars Analogs: Chemical and Physical; Mars Analogs: Sulfates and Sulfides; Missions: Approaches, Architectures, Analogs, and Actualities; Not Just Skin Deep: Electron Microscopy, Heat Flow, Radar, and Seismology Instruments and Planetary Data Systems, Techniques, and Interpretation.

Source record↗
NASA NTRS2013

Flame Suppression Agent, System and Uses

Aqueous droplets encapsulated in a flame retardant polymer are useful in suppressing combustion. Upon exposure to a flame, the encapsulated aqueous droplets rupture and vaporize, removing heat and displacing oxygen to retard the combustion process. The polymer encapsulant, through decomposition, may further add free radicals to the combustion atmosphere, thereby further retarding the combustion process. The encapsulated aqueous droplets may be used as a replacement to halon, water mist and dry powder flame suppression systems.

Parrish, Clyde F.↗
NASA NTRS2014

Producing Zirconium Diboride Components with Complex, Near-Net Shape Geometries by Aqueous Room-Temperature Injection Molding

Room-temperature injection molding is proposed as a novel, low-cost and more energy efficient manufacturing process capable of forming complex-shaped zirconium diboride (ZrB2) parts. This innovative processing method utilized aqueous suspensions with high powder loading and a minimal amount (5 vol.) of water-soluble polyvinylpyrrolidone (PVP), which was used as a viscosity modifier. Rheological characterization was performed to evaluate the room-temperature flow properties of ZrB2-PVP suspensions. ZrB2 specimens were fabricated with high green body strength and were machinable prior to binder removal despite their low polymer content. After binder burnout and pressureless sintering, the bulk density and microstructure of specimens were characterized using Archimedes technique and scanning electron microscopy. X-Ray Diffraction was used to determine the phase compositions present in sintered specimens. Ultimate strength of sintered specimens will be determined using ASTM C1323-10 compressive C-ring test.

Near-Net Shape Forming↗
NASA NTRS2007

Iron Mineralogy and Aqueous Alteration on Mars from the MER Moessbauer Spectrometers

The twin Mars Exploration Rovers Spirit (Gusev crater) and Opportunity (Meridiani Planum) used MIMOS II Moessbauer spectrometers to analyze martian surface materials in the first application of extraterrestrial Moessbauer spectroscopy. The instruments acquired spectra that identified the speciation of Fe according to oxidation state, coordination state, and mineralogical composition and provided quantitative information about the distribution of Fe among oxidation states, coordination states, and Fe-bearing phases. A total of 12 unique Fe-bearing phases were identified: Fe(2+) in olivine, pyroxene, and ilmenite; Fe(2+) and Fe(3+) in magnetite and chromite; Fe(3+) in nanophase ferric oxide (npOx), hematite, goethite, jarosite, an unassigned Fe3+ sulfate, and an unassigned Fe(3+) phase associated with jarosite; and Fe(0) in kamacite. Weakly altered basalts at Gusev crater (SO3 = 2.5 +/- 1.4 wt.% and Fe(3+)/Fe(sub T) = 0.24 +/- 0.11) are widespread on the Gusev plains and occur in less abundance on West Spur and Husband Hill in the Columbia Hills. Altered low-S rocks (SO3 = 5.2 +/- 2.0 wt.% and Fe(3+)/Fe(sub T) = 0.63 +/- 0.18) are the most common type of rock in the Columbia Hills. Ilm-bearing, weakly altered basalts were detected only in the Columbia Hills, as was the only occurrence of chromite in an altered low-S rock named Assemblee. Altered high-S rocks (SO3 > 14.2 wt.% and Fe(3+)/Fe(sub T) = 0.83 +/- 0.05) are the outcrop rocks of the ubiquitous Burns formation at Meridiani Planum. Two Fe(0)-bearing rocks at Meridiani Planum (Barberton and Heat Shield Rock) are meteorites. Laguna Class soil is weakly altered (SO3 = 6 +/- 2 wt.% and Fe(3+)/Fe(sub T) = 0.29 +/- 0.08) and widely distributed at both Gusev crater and Meridiani Planum, implying efficient global mixing processes or a global distribution of precursor rocks with comparable Fe mineralogical compositions. Paso Robles Class soil is heavily altered (SO3 approx. 31 wt.% and Fe(3+)/Fe(sub T) = 0.83 +/- 0.05), is relatively uncommon, and occurs as subsurface deposits in the Columbia Hills. Berry Class soil is also heavily altered (SO3 = 5 +/- 1 wt.% and Fe(3+)/Fe(sub T) = 0.60 +/- 0.13) and occurs at Meridiani Planum as lag deposits, at the crests of aeolian bedforms, and as isolated pockets on outcrop surfaces. Magnetite is identified as the strongly magnetic component in martian soil. Jarosite (in the Burns outcrop at Meridiani Planum) and goethite (in Clovis Class rocks at Gusev crater) are mineralogical markers for aqueous processes because they contain the hydroxide anion (OH(-)) as an essential part of their structure. Each yields approx.10 wt.% H2O upon dehydroxylation. The presence of Fe sulfates on opposite sides of Mars is evidence that aqueous processes under acid sulfate conditions are or were common. Except for Independence Class rocks in the Columbia Hills, the overall Fe mineralogical compositions and similar basaltic bulk chemical compositions (calculated with respect to S = Cl = 0) of the population of altered rocks analyzed by MER imply isochemical alteration of basaltic precursors at low water-to-rock ratios.

Morris, Richard V.↗
NASA NTRS2018

Aqueous Alteration

A secondary process whereby liquid water modified the nature of anhydrous primary nebular components. In general, this process induced decomposition and changed the structures and compositions of primary minerals and formed secondary minerals in their place. This process occurred in the early history of meteorite parent bodies that contained water ice. The most effective heat source is considered to be the decay of short-lived radioactive nuclide such as Aluminium-26, but other causes have been suggested. The degree of aqueous alteration of meteorites is categorized as type 1 (most altered) to type 3 (least altered), according to mineralogy and petrology.

Kebukawa, Yoko↗
NASA NTRS2006

Potential Lifestyles in Ancient Environments of Gusev Crater, Mars

Habitable environments must sustain liquid water at least intermittently and also provide both chemical building blocks and useful sources of energy for life. Observations by Spirit rover indicate that conditions have probably been too dry to sustain life, at least since the emplacement of the extensive basalts that underlie the plains around the Columbia Memorial Station landing site. Local evidence of relatively minor aqueous alteration probably occurred under conditions where the activity of water was too low to sustain biological processes as we know them. In contrast, multiple bedrock units in West Spur and Husband Hill in the Columbia Wills have been extensively altered, probably by aqueous processes. The Fe in several of these units has been extensively oxidized, indicating that, in principle, any microbiota present during the aqueous alteration of these rocks could have obtained energy from Fe oxidation. Spirit discovered oliving-rich ultramafic rocks during her descent from Husband Hill southward into Inner Basin. Alteration of similar ultramafic rocks on Earth can yield H2 that can provide both energy and reducing power for microorganisms. Spirit s discovery of "salty" soil horizons rich in Fe and/or Mg is consistent with the aqueous dissolution and/or alteration of olivine. Such processes can oxidize Fe and also yield H2 under appropriate conditions. Very high S concentrations in these salty deposits indicate that soluble salts were mobilized by water and/or that S oxidation, a potential energy source for life, occurred. The Athena team has not yet established whether these salt components were deposited as large beds in ancient water bodies or, for example, were concentrated by more recent groundwater activity. Collectively these observations are consistent with the possibility that habitable environments existed at least intermittently in the distant geologic past.

DesMarais, David J.↗
NASA NTRS2024

Tracing Presolar Grain Populations Through Matrix Alteration Histories

Primitive meteorites preserve remnants of evolved stars as presolar grains, from asymptotic and red giant branch stars, novae and supernovae. These grains retain records of the formation mechanisms of the stellar environment from which they condensed, as well as physical and chemical processes in the interstellar medium (ISM), solar nebula and the parent bodies in which they are found. Consequently, their study can refine our understanding of the solar system and external stellar and planetary systems. However, presolar grains and their records can be altered, re-equilibrated with the surrounding matrix, and eventually lost through aqueous and thermal processing on the meteorite parent body. NanoSIMS is the most rapid and effective method for in situ identification of presolar grains via their highly anomalous isotopic ratios. Previous studies have measured variations in presolar grain populations between different matrix regions within the same meteorite thin section. However, most of these studies do not identify if there are any ties between these variations in presolar grain populations and the chemical and mineralogical differences in measured matrix regions. Therefore, the goal of this study is to determine if there is measurable variations in the degree of alteration of different matrix regions within the same thin section, and if mineralogical and chemical changes in matrix regions can be used as indicators for presolar grain preservation. Such a correlation could improve the efficiency of presolar grain identification during searches across large surface areas. To do this, we carried out coordinated scanning electron microscope (SEM) and NanoSIMS analyses, using a new SEM method which measures the ppm concentration of 100 nm to 5 μm sized Mg-, S-, Al-, C- and Ca-rich matrix grains.

presolar grains↗
NASA NTRS2010

Potentially Habitable Ancient Environments in Gusev Crater, Mars

Habitable environments must sustain liquid water at least intermittently and also provide both chemical building blocks and useful sources of energy for life. Observations by Spirit rover indicate that conditions have probably been too dry to sustain life, at least since the emplacement of the extensive basalts that underlie the plains around the Columbia Memorial Station landing site. Local evidence of relatively minor aqueous alteration [1] probably occurred under conditions where the activity of water was too low to sustain biological processes as we know them. In contrast, multiple bedrock units in West Spur and Husband Hill in the Columbia Hills have been extensively altered. Patterns of elemental abundances are consistent with aqueous processes involving migrating fluids [2]. Fe in several of these units has been extensively oxidized [3]. Conceivably any microbiota present during the aqueous alteration of these rocks might have obtained energy from Fe oxidation. Spirit discovered olivine-rich ultramafic rocks during her descent from Husband Hill southward into Inner Basin. Alteration of similar ultramafic rocks on Earth can yield H2 that can provide both energy and reducing power for microorganisms. Spirit's discovery of deposits rich in ferric sulfate is consistent with the aqueous dissolution and/or alteration of olivine under acidic conditions [2] such as those associated with hydrothermal activity. The oxidation of iron and sulfur that can accompany such activity can be an energy source for life. Hydrothermal systems on Earth that sustain either acidic [4] or neutral to alkaline fluids [5] have been shown to provide this energy. Collectively the observations by Spirit rover are consistent with the possibility that habitable environments existed in Gusev crater at least intermittently in the distant geologic past.

Fe oxidation↗
NASA NTRS2006

The Origin of Dark Inclusions in Allende: New Evidence from Lithium Isotopes

Aqueous and thermal processing of primordial material occurred prior to and during planet formation in the early solar system. A record of how solid materials were altered at this time is present in the carbonaceous chondrites, which are naturally delivered fragments of primitive asteroids. It has been proposed that some materials, such as the clasts termed dark inclusions found in type III chondrites, suggest a sequence of aqueous and thermal events. Lithium isotopes (Li-6 and Li-7) can reveal the role of liquid water in dark inclusion history. During aqueous alteration, Li-7 passes preferentially into solution leaving Li-6 behind in the solid phase and, consequently, any relatively extended periods of interaction with Li-7-rich fluids would have left the dark inclusions enriched in the heavier isotope when compared to the meteorite as a whole. Our analyses of lithium isotopes in Allende and its dark inclusions reveal marked isotopic homogeneity and no evidence of greater levels of aqueous alteration in dark inclusion history.

Sephton, Mark A.↗
NASA NTRS1997

Replacement Technologies for Precision Cleaning of Aerospace Hardware for Propellant Service

The NASA White Sands Test Facility (WSTF) is developing cleaning and verification processes to replace currently used chlorofluorocarbon-l13- (CFC-113-) based processes. The processes being evaluated include both aqueous- and solvent-based techniques. Replacement technologies are being investigated for aerospace hardware and for gauges and instrumentation. This paper includes the findings of investigations of aqueous cleaning and verification of aerospace hardware using known contaminants, such as hydraulic fluid and commonly used oils. The results correlate nonvolatile residue with CFC 113. The studies also include enhancements to aqueous sampling for organic and particulate contamination. Although aqueous alternatives have been identified for several processes, a need still exists for nonaqueous solvent cleaning, such as the cleaning and cleanliness verification of gauges used for oxygen service. The cleaning effectiveness of tetrachloroethylene (PCE), trichloroethylene (TCE), ethanol, hydrochlorofluorocarbon 225 (HCFC 225), HCFC 141b, HFE 7100(R), and Vertrel MCA(R) was evaluated using aerospace gauges and precision instruments and then compared to the cleaning effectiveness of CFC 113. Solvents considered for use in oxygen systems were also tested for oxygen compatibility using high-pressure oxygen autogenous ignition and liquid oxygen mechanical impact testing.

Harold Beeson↗
NASA NTRS2018

Fluid Inclusions in Astromaterials: Direct Samples of Early Solar System Aqueous Fluids

We have become increasingly aware of the fundamental importance of water, and aqueous alteration, on primitive solar-system bodies. All classes of astromaterials studied show some degree of interaction with aqueous fluids. We have direct observations of cryovolcanism of several small solar system bodies (e.g. Saturnian and Jovian moons), and indirect evidence for this process on the moons Europa, Titan, Ganymede, and Miranda, and the Kuiper Belt object Charon, and so are certain of the continuing and widespread importance of aqueous processes across the solar system. Nevertheless, we are still lacking fundamental information such as the location and timing of the aqueous alteration and the detailed nature of the aqueous fluid itself.

Zolensky, Michael↗
NASA NTRS2004

Conversion Coatings for Aluminum Alloys by Chemical Vapor Deposition Mechanisms

With the rise of environmental awareness and the renewed importance of environmentally friendly processes, the United States Environmental Protection Agency has targeted surface pre-treatment processes based on chromates. Indeed, this process has been subject to regulations under the Clean Water Act as well as other environmental initiatives, and there is today a marked movement to phase the process out in the near future. Therefore, there is a clear need for new advances in coating technology that could provide practical options for replacing present industrial practices. Depending on the final application, such coatings might be required to be resistant to corrosion, act as chemically resistant coatings, or both. This research examined a chemical vapor deposition (CVD) mechanism to deposit uniform conversion coatings onto aluminum alloy substrates. Robust protocols based on solutions of aryl phosphate ester and multi-oxide conversion coating (submicron) films were successfully grown onto the aluminum alloy samples. These films were characterized by X-ray Photoelectron Spectroscopy (XPS). Preliminary results indicate the potential of this technology to replace aqueous-based chromate processes.

Reye, John T.↗