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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.

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At least 775 records · Page 43
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Orbital gamma-ray data and large-scale lunar problems

The orbital gamma-ray data yielded by the Apollo 15 and 16 missions have produced information about lunar differentiation. This information is also applicable to studying lunar petrogenesis using lunar samples. It is shown that the spatial variation in petrogenetic processes, as observed in the K/Th, Fe/Th, and Mg/Fe ratios, is of nearly the same magnitude as that of the lunar samples. The consistent relationship of both mare and nonmare basaltic surface chemical compositions, and the low surface elevation suggests a physical control on the movement of basaltic magma onto the lunar surface.

Hubbard, N. J.↗
NASA NTRS1984

The spatial and seasonal distribution of Martian clouds and some meteorological implications

All Mariner 9 and Viking Orbiter images of Martian atmospheric clouds were analyzed to obtain temporal meteorological characteristics of Mars. The data comprised over 57,000 images which were separated into seven categories of surface obscuration. The classes included: lee waves, waves, plumes, streak clouds, cloud streets, localized fogs and hazes and were associated with particular formation mechanisms, probabilities of wind shear, static stability and surface shear stress and composition. Near surface winds followed the cap edges except in summer. Hemispheric asymmetries were attributed to the hydration state and global dust storm effects. Static stability was regionally and seasonally variable. Finally, clouds formed more easily in the northern than in the southern hemisphere in all corresponding seasons.

Kahn, R.↗
NASA NTRS2022

Sodium Distribution on the Moon

The Moon is significantly depleted in volatile elements when compared to Earth, an observation that has resulted in various formation scenarios leading to the loss of volatiles. Sodium is a moderately volatile element that is a lithophile, which can be utilized as a tracer of the volatile history in planetary bodies. It is also well observed in the exosphere of several bodies in our solar system and exoplanetary systems. But lunar surface sodium abundances have so far been measured only in samples brought back to Earth. We report on results from the first effort to provide a global-scale measurement of sodium on the lunar surface using X-ray fluorescent spectra from Chandrayaan-2. A global average of 1.33 ± 0.03 wt% derived here is higher than previously known. Trends in the sodium abundance indicate a long-lived adsorbate component that could explain the higher abundances reported here, which would act as a reservoir that sustains the lunar sodium exosphere.

Surface composition↗
NASA NTRS2008

System and technique for retrieving depth information about a surface by projecting a composite image of modulated light patterns

A technique, associated system and program code, for retrieving depth information about at least one surface of an object. Core features include: projecting a composite image comprising a plurality of modulated structured light patterns, at the object; capturing an image reflected from the surface; and recovering pattern information from the reflected image, for each of the modulated structured light patterns. Pattern information is preferably recovered for each modulated structured light pattern used to create the composite, by performing a demodulation of the reflected image. Reconstruction of the surface can be accomplished by using depth information from the recovered patterns to produce a depth map/mapping thereof. Each signal waveform used for the modulation of a respective structured light pattern, is distinct from each of the other signal waveforms used for the modulation of other structured light patterns of a composite image; these signal waveforms may be selected from suitable types in any combination of distinct signal waveforms, provided the waveforms used are uncorrelated with respect to each other. The depth map/mapping to be utilized in a host of applications, for example: displaying a 3-D view of the object; virtual reality user-interaction interface with a computerized device; face--or other animal feature or inanimate object--recognition and comparison techniques for security or identification purposes; and 3-D video teleconferencing/telecollaboration.

Hassebrook, Laurence G.↗
DOE OSTI2020

Crewmember microbiome may influence microbial composition of ISS habitable surfaces

The International Space Station (ISS) is a complex built environment physically isolated from Earth. Assessing the interplay between the microbial community of the ISS and its crew is important for preventing biomedical and structural complications for long term human spaceflight missions. In this study, we describe one crewmember’s microbial profile from body swabs of mouth, nose, ear, skin and saliva that were collected at eight different time points pre-, during and post-flight. Additionally, environmental surface samples from eight different habitable locations in the ISS were collected from two flights. Environmental samples from one flight were collected by the crewmember and samples from the next flight were collected after the crewmember departed. The microbial composition in both environment and crewmember samples was measured using shotgun metagenomic sequencing and processed using the Livermore Metagenomics Analysis Toolkit. Ordination of sample to sample distances showed that of the eight crew body sites analyzed, skin, nostril, and ear samples are more similar in microbial composition to the ISS surfaces than mouth and saliva samples; and that the microbial composition of the crewmember’s skin samples are more closely related to the ISS surface samples collected by the crewmember on the same flight than ISS surface samples collected by other crewmembers on different flights. In these collections, species alpha diversity in saliva samples appears to decrease during flight and rebound after returning to Earth. This is the first study to compare the ISS microbiome to a crewmember’s microbiome via shotgun metagenomic sequencing. We observed that the microbiome of the surfaces inside the ISS resemble those of the crew’s skin. These data support future crew and ISS microbial surveillance efforts and the design of preventive measures to maintain crew habitat onboard spacecraft destined for long term space travel.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS2014

Alteration of the Carbon and Nitrogen Isotopic Composition in the Martian Surface Rocks Due to Cosmic Ray Exposure

C-13/C-12 and N-15/N-14 isotopic ratios are pivotal for our understanding of the Martian carbon cycle, history of the Martian atmospheric escape, and origin of the organic compounds on Mars. Here we demonstrate that the carbon and nitrogen isotopic composition of the surface rocks on Mars can be significantly altered by the continuous exposure of Martian surface to cosmic rays. Cosmic rays can effectively produce C-13 and N-15 isotopes via spallation nuclear reactions on oxygen atoms in various Martian rocks. We calculate that in the top meter of the Martian rocks, the rates of production of both C-13 and N-15 due to galactic cosmic rays (GCRs) exposure can vary within 1.5-6 atoms/cm3/s depending on rocks' depth and chemical composition. We also find that the average solar cosmic rays can produce carbon and nitrogen isotopes at a rate comparable to GCRs in the top 5-10 cm of the Martian rocks. We demonstrate that if the total carbon content in a surface Martian rock is <10 ppm, then the "light," potentially "biological" C-13/C-12 ratio would be effectively erased by cosmic rays over 3.5 billion years of exposure. We found that for the rocks with relatively short exposure ages (e.g., 100 million years), cosmogenic changes in N-15/N-14 ratio are still very significant. We also show that a short exposure to cosmic rays of Allan Hills 84001 while on Mars can explain its high-temperature heavy nitrogen isotopic composition (N-15/N-14). Applications to Martian meteorites and the current Mars Science Laboratory mission are discussed.

cosmic ray exposure↗
NASA NTRS2002

Properties of M40J Carbon/PMR-II-50 Composites Fabricated with Desized and Surface Treated Fibers. Characterization of M40J Desized and Finished Fibers

To increase performance and durability of high temperature composites for potential rocket engine components, it is necessary to optimize wetting and interfacial bonding between high modulus carbon fibers and high temperature polyimide resins. It has been previously demonstrated that the electro-oxidative shear treatments used by fiber manufacturers are not effective on higher modulus fibers that have fewer edge and defect sites in the surface crystallites. In addition, sizings commercially supplied on most carbon fibers are not compatible with polyimides. This study was an extension of prior work characterizing the surface chemistry and energy of high modulus carbon fibers (M40J and M60J, Torray) with typical fluorinated polyimide resins, such as PMR-II-50. A continuous desizing system which utilizes environmentally friendly chemical- mechanical processes was developed for tow level fiber and the processes were optimized based on weight loss behavior, surface elemental composition (XPS) and morphology (FE-SEM) analyses, and residual tow strength of the fiber, and the similar approaches have been applied on carbon fabrics. Both desized and further treated with a reactive finish were investigated for the composite reinforcement. The effects of desizing and/or subsequent surface retreatment on carbon fiber on composite properties and performance including fiber-matrix interfacial mechanical properties, thermal properties and blistering onset behavior will be discussed in this presentation.

Allred, Ronald E.↗
NASA NTRS1990

Interlaminar fracture in carbon fiber/thermoplastic composites

The surfaces of commercial carbon fibers are generally chemically cleaned or oxidized and then coated with an oligomeric sizing to optimize their adhesion to epoxy matrix resins. Evidence from fractography, from embedded fiber testing and from fracture energies suggests that these standard treatments are relatively ineffective for thermoplastic matrices. This evidence is reviewed and model thermoplastic composites (polyphenylene oxide/high strain carbon fibers) are used to demonstrate how differences in adhesion can lead to a twofold change in interlaminar fracture toughness. The potential for improved adhesion via plasma modification of fiber surfaces is discussed. Finally, a surprising case of fiber-catalyzed resin degradation is described.

Hinkley, J. A.↗
NASA NTRS2010

System and technique for retrieving depth information about a surface by projecting a composite image of modulated light patterns

A technique, associated system and program code, for retrieving depth information about at least one surface of an object, such as an anatomical feature. Core features include: projecting a composite image comprising a plurality of modulated structured light patterns, at the anatomical feature; capturing an image reflected from the surface; and recovering pattern information from the reflected image, for each of the modulated structured light patterns. Pattern information is preferably recovered for each modulated structured light pattern used to create the composite, by performing a demodulation of the reflected image. Reconstruction of the surface can be accomplished by using depth information from the recovered patterns to produce a depth map/mapping thereof. Each signal waveform used for the modulation of a respective structured light pattern, is distinct from each of the other signal waveforms used for the modulation of other structured light patterns of a composite image; these signal waveforms may be selected from suitable types in any combination of distinct signal waveforms, provided the waveforms used are uncorrelated with respect to each other. The depth map/mapping to be utilized in a host of applications, for example: displaying a 3-D view of the object; virtual reality user-interaction interface with a computerized device; face--or other animal feature or inanimate object--recognition and comparison techniques for security or identification purposes; and 3-D video teleconferencing/telecollaboration.

Hassebrook, Laurence G.↗
NASA NTRS1987

Elemental composition of the Martian surface

The Viking landers carried X-ray fluorescence spectrometers (XRFS) to the surface of Mars for direct in-situ measurements of the elemental composition of samples that could be acquired by the surface sampler scoops. A total of 21 samples at two landing sites were acquired and analyzed. In this review, the constraints imposed on the design and operation of the XRFS; the accuracy and precision limitations of XRF; and the interpretation of the results are discussed. The latter includes relevance of the investigation to Martian geological processes, SNC meteorites, the formation and history of Mars, and future mission objectives/capabilities.

Clark, Benton C.↗
DOE OSTI2024

Analysis of the Surface Morphology and Chemical Composition of Zr-Nb3Sn Alloys with Different Zr Concentrations

In the field of superconducting science, Nb has been the material of choice for Radio Frequency (RF) Cavities for years. However, in recent years Nb3Sn has shown to be a promising alternative to Nb. Its combination of a significantly high superconducting transition temperature and a much higher value of upper critical magnetic field (Hc2), has been the reason the alloy has been so widely studied. This project aims to develop materials to further improve the high magnetic field performance of Nb3Sn by improving its upper critical magnetic field and critical current density (Jc). One way to improve the Jc and the Hc2 is to create more grain boundaries in the Nb3Sn alloy allowing them to trap more magnetic flux lines in the materials. To do this the grains must be made smaller which will naturally cause the formation of more grain boundaries. A common way to create smaller grains is by doping an impurity in the alloy. In this study, Nb3Sn was doped with Zr to form Zr-Nb3Sn alloys. This project investigates the surface properties and chemical composition of Zr-Nb3Sn alloys with varying zirconium concentrations (~0.5% and ~24% Zr). Using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and X-ray Photoemission Spectroscopy (XPS), allowed for the characterization of the differences in surface morphology and elemental composition between samples. SEM images were quantified using ImageJ giving insight into grain distribution. The results indicate that increased Zr concentration creates smaller grains in the Zr-Nb3Sn alloy. Furthermore, the ~ 24% Zr grew nanoscale particles on the surface that are possible oxides. XPS data revealed that as Zr concentration increased, the total Nb oxides (NbOx) thickness decreased. Conversely, as Zr concentration increased, the surface Sn oxides (SnOx) also increased slightly. Quantification via ImageJ of SEM data showed that the ~ 0.5% Zr sample had a grain size of ~ 5300 nm2. These results show that Zr inclusion leads to smaller grain formations, which is promising in the world of superconducting RF cavities for high magnetic field applications.

Sue, Micah↗
NASA NTRS1973

Chemistry of the moon's surface

The chemical composition of the lunar surface is discussed on the basis of analyses of Apollo samples. Three new minerals, armalcolite, pyroxferroite and tranquillityite, high abundances of Ti, Zr, Sr, Y, Nb, U and Th, and a predominance of radiogenic isotopes of Pb are noted as the prominent features unraveled by sample analysis. Evidence is indicated to support the conclusion that the lunar rocks investigated are products of partial fusion and magmatic crystallization modified in much of the material by mechanical breakup and shock melting, and containing a small amount of meteoritic material. It is inferred from the results that the surface rocks are igneous in origin and that the moon has been a passive object since 3000 million years ago.

Mason, B.↗
NASA NTRS1986

Development of composite facets for the surface of a space-based solar dynamic concentrator

An account is given of the composite fabrication techniques envisioned for the production of mirror-quality substrates furnishing the specular reflectance required for the NASA Space Station's solar dynamic concentrator energy system. The candidate materials were graphite fiber-reinforced glass, aluminum, and polymer matrices whose surfaces would be coated with thin metal layers and with atomic oxygen degradation-inhibiting protective coatings to obtain the desired mirror surface. Graphite-epoxy mirror substrate samples have been found to perform satisfactorily for the required concentrator lifetime.

Ayers, Schuyler R.↗
NASA NTRS1983

Surface analysis of grapite fiber reinforced polyimide composites. I

The results of experimental analyses of the effects of pretreatment on bonding between composite materials are reported. The materials comprised graphite fibers in a polyimide matrix. The surfaces were bonded as-received or subjected to grit blasting, bead blasting, hand sanding, washes with ethanolic KOH, NH2NH2-H2O or H2SO4 + 0.30 H2O2 or flashblasting. SEM and X-ray photoelectron spectroscopy revealed fluorine contents in the as-received samples. Contact angles were determined by means of five different liquids with various surface tensions. The flashblast technique removed all fluorine from the samples. Low critical surface tensions were found in the composite surfaces with high fluorine concentrations. The surface scanning techniques are concluded to be useful for studying factors influencing the strength and durability of adhesively bonded composites.

Messick, D. L.↗
NASA NTRS1993

Surface characterization of LDEF materials

The NASA Long Duration Exposure Facility (LDEF), a passive experimental satellite, was placed into low-Earth orbit by the Shuttle Challenger in Apr. 1984. The LDEF spent an unprecedented 69 months in space. The flight and recovery of the LDEF provided a wealth of information on the longterm space environmental effects of a variety of materials exposed to the low-Earth orbit environment. Surface characterization of LDEF materials included polymers, composites, thermal control paints, and aluminum. X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), scanning electron microscopy (SEM), and contact angle analysis were used to document changes in both the surface composition and surface chemistry of these materials. Detailed XPS analysis of the polymer systems, such as Kapton, polyimide polysiloxane copolymers, and fluorinated ethylene propylene thermal blankets on the backside of the LDEF revealed significant changes in both the surface composition and surface chemistry as a result of exposure to the low-Earth orbit environment. Polymer systems such as Kapton, polyimide polysiloxane copolymers, and polysulfone showed a common trend of decreasing carbon content and increasing oxygen content with respect to the control sample. Carbon 1s curve fit XPS analysis of the composite samples, in conjunction with SEM photomicrographs, revealed significant ablation of the polymer matrix resin to expose the carbon fibers of the composite during exposure to the space environment. Surface characterization of anodized aluminum tray clamps, which were located at regular intervals over the entire LDEF frame, provided the first results to evaluate the extent of contamination with respect to position on the LDEF. The XPS results clearly showed that the amount and state of both silicon and fluorine contamination were directly dependent upon the position of the tray clamp on the LDEF.

Wightman, J. P.↗
NASA NTRS1985

Magmas as Selective Filters of Volatiles Between Planetary Mantles and Surfaces

The composition of early planetary atmospheres and biospheres which is a knowledge of the relationship between mantle volatiles and volcanic gases was analyzed. In the case of Earth it appears that volcanic rocks and gases are relatively oxidized compared to the upper mantle. In the case of the C-O-H volatiles, (H2O, CO2, CO, CH4, H2) the volcanic gases are enriched in H2O and CO2 while the volatiles in the mantle may be dominated by H2O, H2 and possibly CH4. An experimental technique was perfected for phase equilibrium studies in the 5-30 kbar range which allows accurate control of volatile species activities in the fluid phase. The system was used to measure the relative solubilities of H2O, CO2, CO, CH4 and H2 in magmas at 10 kbar pressure. It is found that mantle magmas will selectively screen volatiles from planetary surfaces, forcing volcanic gases towards the neutral QFM oxidation state where H2O is the dominant species.

Holloway, J. R.↗
NASA NTRS1979

Magnetite in CI carbonaceous meteorites - Origin by aqueous activity on a planetesimal surface

The composition and morphology of magnetite in CI carbonaceous meteorites appear incompatible with a nebular origin. Mineralization on the meteorite parent body is a more plausible mode of formation. The iodine-xenon age of this material therefore dates an episode of secondary mineralization on a planetesimal rather than the epoch of condensation in the primitive solar nebula.

Kerridge, J. F.↗