Search NASA⌕ Search

SEARCH · Search NASA

Results for “RICH”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS2006

The Role of CO2 in Aqueous Alteration of Ultra-Mafic Rocks and the Formation of MF-,FE-Rich Aqueous Solutons on Early Mars

An adequate understanding of water on Mars that moves beyond the simplistic "warmwet" vs. "cold-dry" dichotomy must include strong constraints on the variables: water/rock ratio, time, temperature, and chemical composition. By constraining these variables first on local, then regional and global scales we will be capable of precisely targeting landed missions to definitively understand the history of water on Mars and the possible existence of life. Data from remote sensing of Mars, landed missions, and martian meteorites indicate that secondary minerals formed from aqueous fluids on Mars are predominately Fe- and Mg-rich. The unique Mg-, Fe-rich carbonates in the ALH 84001 meteorite provide an excellent opportunity to provide strong constraints on an Fe-, Mg-rich aqueous system on early Mars. This work seeks to use the unusual chemical compositions of the ALH 84001 carbonates as a constraint for the composition of their formation fluid. These constraints can be used to better understand aqueous processes at a critical time in martian history.

Niles, Paul B.↗
NASA NTRS2012

Characterizing of a Mid-Latitude Ice-Rich Landing Site on Mars to Enable in Situ Habitability Studies

We suggest an ice-rich landing site at 188.5E 46.16N within Amazonis Planitia as a candidate location to support a Mars lander mission equipped to study past habitability and regions capable of preserving the physical and chemical signs of life and organic matter. Studies of the ice-rich subsurface on Mars are critical for several reasons. The subsurface environment provides protection from radiation to shield organic and biologic compounds from destruction. The ice-rich substrate is also ideal for preserving organic and biologic molecules and provides a source of H2O for biologic activity. Examination of martian ground ice can test several hypotheses such as: 1) whether ground ice supports habitable conditions, 2) that ground ice can preserve and accumulate organic compounds, and 3) that ice contains biomolecules evident of past or present biological activity on Mars. This Amazonis site, located near the successful Viking Lander 2, shows indirect evidence of subsurface ice (ubiquitous defined polygonal ground, gamma ray spectrometer hydrogen signature, and numerical modeling of ice stability) and direct evidence of exposed subsurface ice. This site also provides surface conditions favorable to a safe landing including no boulders, low rock density, minimal rough topography, and few craters.

Heldmann, J.↗
NASA NTRS2012

Rb-Sr Isotopic Systematics of Alkali-Rich Fragments in the Yamato-74442 LL-Chondritic Breccia

Alkali-rich igneous fragments were identified in the brecciated LL-chondrites, Kr henberg (LL5)], Bhola (LL3-6) and Yamato (Y)-74442 (LL4), and show characteristic fractionation patterns of alkaline elements. The K-Rb-Cs-rich fragments in Kr henberg, Bhola, and Y-74442 are very similar in mineralogy and petrography (olivine + pyroxene + glass), suggesting that they could have come from related precursor materials. We have undertaken Rb-Sr isotopic studies on alkali-rich fragments in Y-74442 to precisely determine their crystallization ages and the isotopic signatures of their precursor material(s).

Yokoyama, T.↗
NASA NTRS2015

Evidence of Metasomatism in the Lowest Petrographic Types Inferred from A Na(-), K, Rich Rim Around A LEW 86018 (L3.1) Chondrule

Ordinary chondrites (OCs) represent the most abundant extraterrestrial materials and also record the widest range of alteration of primary, pristine minerals of early Solar system material available for study. Relatively few investigations, however, address: (1) the role of fluid alteration, and (2) the relationship between thermal metamorphism and metasomatism in OCs, issues that have been extensively studied in many other meteorite groups e.g., CV, CO, CR, and enstatite chondrites. Detailed elemental abundances profiles across individual chondrules, and mineralogical studies of Lewis Hills (LEW) 86018 (L3.1), an unequilibrated ordinary chondrite (UOC) of low petrographic type of 3.1 returned from Antarctica, provide evidence of extensive alteration of primary minerals. Some chondrules have Na(-), K(-), rich rims surrounded by nepheline, albite, and sodalite-like Na(-), Cl(-), Al-rich secondary minerals in the near vicinity within the matrices. Although, limited evidences of low temperature (approximately 250 C) fluid-assisted alteration of primary minerals to phyllosilicates, ferroanolivine, magnetite, and scapolite have been reported in the lowest grades (less than 3.2) Semarkona (LL3.00) and Bishunpur (LL3.10), alkali-rich secondary mineralization has previously only been seen in higher grade greater than 3.4 UOCs. This preliminary result suggests highly localized metamorphism in UOCs and widens the range of alteration in UOCs and complicates classification of petrographic type and extent of thermal metamorphism or metasomatism. The work in progress will document the micro-textures, geochemistry (Ba, Ca, REE), and isotopic composition (oxygen, Al(-)- 26 Mg-26) of mineral phases in chondrules and adjoining objects to help us understand the formation scenario and delineate possible modes of metamorphism in UOCs.

Mishra, Ritesh Kumar↗
NASA NTRS2019

Microstructural Record of Evolving Condensation Processes in Fine-Grained Ca-Al-Rich Inclusions from the Reduced CV3 Chondrites

Fine-grained, spinel-rich Ca-Al-rich inclusions (FGIs) in carbonaceous chondrites consist of numerous layered nodules having cores of spinel, hibonite, and/or perovskite surrounded by multiple thin layers of melilite, anorthite, diopside, and/or olivine. They are interpreted as aggregates of direct high-temperature condensates from an 16O-rich nebular gas that escaped significant melting. However, FGIs are very complex objects composed of intimate intergrowths of fine-grained refractory phases and show extremely large variations in mineralogy, modal abundance, and textures. Thus, detailed FIB/TEM analyses of FGIs are required to fully characterize their micro-to-nanometer scale textures, mineralogy, and chemical compositions and hence elucidate their formation processes and conditions in the early solar nebula. Here, we present our on-going study of pristine FGIs from the reduced CV3 chondrites Efremovka and Thiel Mountains (TIL) 07003 and 07007 that have minimal evidence for secondary parent body alteration.

Han, J.↗
NASA NTRS2019

Recent Developments in the Curation of Cold, Volatile-Rich Extraterrestrial Samples

In recent years, the study of samples from cold, potentially volatile-rich Solar System bodies has increased dramatically. Returned samples from low- or cryogenic-temperature regions are highly sensitive to ambient temperatures, pressures, and materials. In order to maximize the scientific utility of such samples, they must be returned, handled, and stored under conditions that minimize sample alteration and contamination. The Johnson Space Center (JSC) Astromaterials Acquisition and Curation Office (hereafter called the Curation Office) is currently developing the ability to curate cold, volatile-rich samples; this abstract summarizes these efforts for Apollo lunar samples, organic-rich meteorites, comet samples, and lunar polar samples.

Mitchell, J. L.↗
NASA NTRSDate not supplied

Compositional Clues to the Origin of Refractory Metal Nuggets, Perovskite, and Zr-Rich Oxides in Hibonite from the Paris Cm Chondrite

Rare Ca-Al-rich inclusions (CAIs) in carbonaceous chondrites are dominated by Zr-, Sc-, Ti-,and/or Y-rich oxides and silicates, and often contain refractory metal nuggets (RMNs)[1-3]. These phases have ultra refractory (UR) rare earth element (REE)patterns that are complementary to Group II patterns[4]. Therefore, studies of such UR CAIs likely decipher a record of nebular conditions and processes at higher temperatures than other CAIs consisting mainly of spinel and melilite. Our previous TEM analyses reported a discovery of the assemblages of RMNs, perovskite, and Zr-rich oxides in hibonite from the Paris CM chondrite[5]. Here we present TEM results of a detailed chemical study of these UR phases to provide clues to their formation conditions in the early solar nebula.

J Han↗
NASA NTRSDate not supplied

Terrestrial Aqueously Altered Magmatic Dike Forming Sulfate-Rich Hydrothermal Fluids to Constrain Martian Habitability

Intrusion of magma into a water-bearing crust can create a habitable hydrothermal environment, as seen on Earth. As the rock surrounding the intrusion is subjected to heat it can 1) release water, and different chemical species, from pre-existing minerals, and 2) interact with volatiles released from the cooling magma, which can create a geothermal brine with a distinct composition suitable for a range of chemotrophs. Hence, studying such environments on Earth is important in the search for life beyond our planet. The geothermal brine’s nature is dependent on the host rock and the magmatic properties. On Mars basaltic and sulfur-rich soils are dominant and therefore investigating basaltic magmatic interaction with sulfate-rich sediments and their associated habitats is key for recognizing potential habitats on Mars. The NASA Perseverance Rover at Jezero Crater has detected aqueously altered igneous rocks, potentially intrusive in origin, with secondary carbonates, sodium perchlorate and sulfates. Such an environment may have been habitable. Therefore, we investigate the intrusion of a magmatic dike into Jurassic sulfate-rich sediments from the San Rafael Swell, Utah, to reconstruct the geothermal fluids and assess their putative habitability.

B Baharier↗
NASA NTRSDate not supplied

The Chemical and Isotopic Signatures of the Hibonite-rich FUN Inclusion "HIDALGO" in Dar al Gani 027 (CO3)

Refractory Ca-Al-rich Inclusions (CAIs) with FUN (Fractionation with Unidentified Nuclear effects) characteristics are peculiar samples among all high-temperature components in chondritic meteorites. They are generally characterized by strong mass-dependent isotopic fractionations in several elements (e.g., O, Mg, Ca, Ti), large (~5-20‰) enrichments or depletions in neutron-rich isotopes (e.g., 48 Ca, 50 Ti, 54 Cr), and low inferred abundances of 26 Al ( 26 Al/ 27 Al < 1×10 −5 ). Understanding the origins of these features in FUN CAIs can shed light on the astrophysical environment and chemical processes that took place in the early Solar System. A large fraction (slightly less than 50%) of the ~20 FUN CAIs discovered so far are hibonite-rich (such as HAL, SHAL and DH-H1, collectively called HAL-type inclusions hereafter). According to their elemental and isotopic signatures and the results of evaporation experiments, HAL-type inclusions are thought to have formed as a distillation residue. However, questions regarding the timing of the formation of HAL-type inclusions (or FUN inclusions in general) relative to those of regular CAIs and the decoupling between the 26 Al abundances and nucleosynthetic anomalies remain poorly understood. In 2021, we reported the discovery of a new HAL-type inclusion, HIDALGO (Hibonite in Dar al Gani CO3) in the CO3 chondrite Dar al Gani 027 (DaG027), based on its (fractionated) oxygen isotopic compositions and low inferred 26 Al/ 27 Al ratio of (1.50±0.02)×10 −5 . Since then, more work on other short-lived and stable isotope systems and trace element abundances has been conducted. Here we report these new results and discuss the implications for the possible formation history of HIDALGO and origins of shortlived radionuclides (SLRs).

Meteorite↗
NASA NTRS2024

What Are the Olivine-Rich Boulders in the Upper Fan and Margin Unit at Jezero Crater, Mars?

Since February 2021, the Perseverance rover has explored Jezero Crater in the Nili Fossae region of Mars which hosts large outcrops of a regional olivine-carbonate unit. In the crater floor, Perseverance investigated two igneous formations: Máaz, composed of basaltic lava and/or pyroclastic flows, and Séítah, an olivine-rich cumulate] below Máaz. Then, Perseverance explored the western fan composed by diverse sedimentary rocks of variable composition, but often containing olivine On the upper fan and margin unit, Perseverance encountered number of centimetric to metric boulder rocks. Two main types of boulders were identified based on texture and composition: the olivine-rich and pyroxene-bearing boulders. Here, we use SuperCam data to describe the texture, geochemistry and mineralogy of the olivine-rich boulders. Then, we discuss their possible petrological origin and some possible implications for the regional Nili Fossae olivine-carbonate unit.

Mars 2020↗
NASA NTRS2024

A Coordinated Mineralogical and Oxygen Isotopic Study of Refractory Ca-Al-Rich Inclusions

Refractory Ca-Al-rich inclusions (CAIs) in primitive chondritic meteorites represent the oldest solids that formed in our Solar System. Coordinated analyses using multiple ion and electron-beam techniques are vital to fully understand complex nebular and asteroidal processes that CAIs may have experienced in the context of the formation and early evolution of our Solar System. We report the results of a coordinated mineralogical and oxygen isotopic study of unique grossite bearing CAIs from reduced CV (Vigarano type) carbonaceous chondrites using transmission electron microscopy and secondary ion mass spectrometry. Grossite (CaAl 4 O 7 ) occurs in cores of nodules in fine grained CAIs that likely represent aggregates of nebular condensates. In many occurrences, grossite has been partially replaced by hercynite [(Fe,Mg,Zn)Al 2 O 4 ], which displays complex microstructures and compositions, and magnetite nanoparticles. This grossite alteration likely occurred via crystallographically controlled metasomatic reactions with Zn, Fe-rich aqueous fluids on the parent asteroid. The constituent phases of grossite bearing CAIs show heterogeneous oxygen isotopic compositions . That is, grossite and perovskite are 16 O poor and melilite is variably 16 O-depleted in contrast to solar like, 16 O-rich hibonite and spinel. The observed oxygen isotopic distribution is interpreted as a result of mineralogically controlled oxygen isotopic exchange with an 16 O-poor fluid on the parent asteroid. Collectively, we conclude that the presence of limited fluids played an important role in preferential alteration of grossite to hercynite and magnetite and various degrees of 16 O depletion in grossite, perovskite, and melilite during thermal metamorphism on the CV chondrite parent asteroid.

Jangmi Han↗
NASA NTRS1995

Stable loop in the crystal structure of the intercalated four-stranded cytosine-rich metazoan telomere

In most metazoans, the telomeric cytosine-rich strand repeating sequence is d(TAACCC). The crystal structure of this sequence was solved to 1.9-A resolution. Four strands associate via the cytosine-containing parts to form a four-stranded intercalated structure held together by C.C+ hydrogen bonds. The base-paired strands are parallel to each other, and the two duplexes are intercalated into each other in opposite orientations. One TAA end forms a highly stabilized loop with the 5' thymine Hoogsteen-base-paired to the third adenine. The 5' end of this loop is in close proximity to the 3' end of one of the other intercalated cytosine strands. Instead of being entirely in a DNA duplex, this structure suggests the possibility of an alternative conformation for the cytosine-rich telomere strands.

NASA Discipline Exobiology↗
NASA NTRS1972

X-ray emission from rich clusters of galaxies.

Evaluation of the newly published Uhuru catalog, revealing significant number of rich clusters associated with X-ray sources. Combined with earlier observations of X-ray emission from the Virgo, Coma, and Perseus clusters, this suggests that most, if not all, rich clusters include an X-ray emission region of large size and of net luminosity from 10 to the 43rd to 10 to the 44th ergs/sec.

Gursky, H.↗
NASA NTRS1975

Coacervate-like microspheres from lysine-rich proteinoid

Microspheres form isothermally from lysine-rich proteinoid when the ionic strength of the solution is increased with NaCl or other salts. Studies with different monovalent anions and with polymers of different amino acid composition indicate that charge neutralization and hydrophobic bonding contribute to microsphere formation. The particles also form in sea water, especially if heated or made slightly alkaline. The microspheres differ from those made from acidic proteinoid but resemble coacervate droplets in some ways (isothermal formation, limited stability, stabilization by quinone, uptake of dyes). Because the constituent lysine-rich proteinoid is of simulated prebiotic origin, the study is interpreted to add emphasis to and suggest an evolutionary continuity for coacervation phenomena.

Rohlfing, D. L.↗
NASA NTRS1976

Hydrogen rich gas generator

A process and apparatus is described for producing a hydrogen rich gas by injecting air and hydrocarbon fuel at one end of a cylindrically shaped chamber to form a mixture and igniting the mixture to provide hot combustion gases by partial oxidation of the hydrocarbon fuel. The combustion gases move away from the ignition region to another region where water is injected to be turned into steam by the hot combustion gases. The steam which is formed mixes with the hot gases to yield a uniform hot gas whereby a steam reforming reaction with the hydrocarbon fuel takes place to produce a hydrogen rich gas.

Houseman, J.↗
NASA NTRS1976

Modulation of solar flare particles and track density profiles in gas-rich meteorite grains

A solution is presented to the problem concerning the time-averaged solar flare particle flux as a function of kinetic energy and distance from the sun for a given particle injection spectrum at the sun within the framework of standard diffusion-convection-adiabatic deceleration theory with the diffusion coefficient independent of distance from the sun. Results of the calculations which give best agreement with observations at 1 AU are presented and discussed, with particular reference to their implications for gas-rich meteorites. Normalization at the orbit of earth is achieved via observed track density versus depth profiles in lunar vug crystals. It is shown that if gas-rich meteorite grains were irradiated in the asteroid belt and if source and modulation parameters have changed little since irradiation, the track density should be 'harder' than the lunar vug profile by about 0.2-0.3 in the index. Quantitative estimation of solar flare particle exposure ages is discussed.

Lee, M. A.↗
NASA NTRS1976

Hydrogen-rich gas generator

A process and apparatus are described for producing hydrogen-rich product gases. A spray of liquid hydrocarbon is mixed with a stream of air in a startup procedure and the mixture is ignited for partial oxidation. The stream of air is then heated by the resulting combustion to reach a temperature such that a signal is produced. The signal triggers a two way valve which directs liquid hydrocarbon from a spraying mechanism to a vaporizing mechanism with which a vaporized hydrocarbon is formed. The vaporized hydrocarbon is subsequently mixed with the heated air in the combustion chamber where partial oxidation takes place and hydrogen-rich product gases are produced.

Houseman, J.↗
NASA NTRS1977

The structure of cometary ionospheres. II - CO-rich comets

The structure of the ionosphere of a CO-rich comet is computed using two different models. The first one, the photochemical model, assumes that the dissociation and ionization of cometary neutrals and ions are due to photoionization, and photodissociation by solar UV radiation together with dissociative recombinations and ion-neutral reactions. The second one, the internal source model, also incorporates the ionization and dissociation effects of an electric current discharging through the inner coma. The generation of this current has been discussed in earlier papers. It is concluded that the internal source model can explain qualitatively the basic morphology of the ionospheres of CO-rich comets such as Humason (1962, VIII) and Morehouse (1908, III), whereas the photochemical model cannot. The main aim of this paper is not so much to provide accurate numerical estimates as to draw attention to a process which may very well dominate the structures of cometary ionospheres.

Ip, W.-H.↗