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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 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
NASA NTRS2002

Stirling Technology Development at NASA GRC

The Department of Energy, Stirling Technology Company (STC), and NASA Glenn Research Center (NASA Glenn) are developing a free-piston Stirling convertor for a high-efficiency Stirling Radioisotope Generator (SRG) for NASA Space Science missions. The SRG is being developed for multimission use, including providing electric power for unmanned Mars rovers and deep space missions. NASA Glenn is conducting an in-house technology project to assist in developing the convertor for space qualification and mission implementation. Recent testing, of 55-We Technology Demonstration Convertors (TDC's) built by STC includes mapping, of a second pair of TDC's, single TDC testing, and TDC electromagnetic interference and electromagnetic compatibility characterization on a nonmagnetic test stand. Launch environment tests of a single TDC without its pressure vessel to better understand the convertor internal structural dynamics and of dual-opposed TDC's with several engineering mounting structures with different natural frequencies have recently been completed. A preliminary life assessment has been completed for the TDC heater head, and creep testing of the IN718 material to be used for the flight convertors is underway. Long-term magnet aging tests are continuing to characterize any potential aging in the strength or demagnetization resistance of the magnets used in the linear alternator (LA). Evaluations are now beginning on key organic materials used in the LA and piston/rod surface coatings. NASA Glenn is also conducting finite element analyses for the LA, in part to look at the demagnetization margin on the permanent magnets. The world's first known integrated test of a dynamic power system with electric propulsion was achieved at NASA Glenn when a Hall-effect thruster was successfully operated with a free-piston Stirling power source. Cleveland State University is developing a multidimensional Stirling computational fluid dynamics code to significantly improve Stirling loss predictions and assist in identifying convertor areas for further improvements. This paper will update the status and results for these efforts.

Thieme, Lanny G.↗
NASA NTRS1981

Interplanetary dust - Its physical nature and entry into the atmosphere of terrestrial planets

Studies of extraterrestrial particles collected in the stratosphere and from the sea floor indicate that the majority of interplanetary dust is a black, fine grained material similar to carbonaceous chondrites but different from known meteorites in mineralogy and structure. If the analyzed samples are typical interplanetary particles then they are probably cometary materials similar to the vast numbers of cometary particles which have continuously entered the earth's atmosphere for the lifetime of the solar system. If comets do not contain large strong rocks capable of producing conventional meteorites then dust is the only form in which organic materials from comets can be accreted by the earth.

Brownlee, D. E.↗
NASA NTRS2016

MOMA: The Challenge to Search for Organics and Biosignatures on Mars

This paper describes strategies to search for, detect, and identify organic material on the surface and subsurface of Mars. The strategies described include those applied by landed missions in the past and those that will be applied in the future. The value and role of ESA's ExoMars rover and of her key science instrument Mars Organic Molecule Analyzer (MOMA) are critically assessed.

Goetz, Walter↗
NASA NTRSDate not supplied

Surface-Enhanced Raman Spectroscopy (SERS) for Venus Atmospheric Characterization and Trace Organics Identification

The chemical composition of Venus’ clouds has attracted considerable attention since the first atmospheric probes entered the planet in the early 1980s. We know from these early studies that cloud aerosols consist of micron and submicron droplets of sulfuric acid (~85%) and water (~15%), but outstanding questions still exist regarding their trace chemical composition, especially the identity of the unknown UV absorber(s) and the possible presence of organic material (Spacek & Benner, 2021). Veritas and DaVinci will launch at the end of the decade to advance our understanding of Venus’ surface and atmosphere, however these missions are not designed to sample and analyze cloud aerosols at trace levels. Raman spectroscopy is an ideal candidate for characterizing aerosols and has a track record in studies of Earth’s atmosphere. Raman provides broad chemical screening of organic and inorganic molecules within seconds, and Raman instrumentation can be miniaturized to meet the stringent size, weight, and power (SWaP) constraints of an atmospheric probe while retaining sensitivity and specificity that allow spectral fingerprinting of compounds and functional groups. Raman alone is insufficient to characterize trace constituents however, as limits of detection are typically in the 10s to 100s of ppm at best for planetary Raman spectrometers. Surface-Enhanced Raman Spectroscopy (SERS), a method that utilizes nanoscale materials interacting with a sample to enhance weak Raman signals by orders of magnitude when probed by a laser, has the potential to drastically improve the sensitivity of a Raman instrument while adding little-to-no SWaP nor complexity to a scientific payload. We aim to de-risk SERS technology for rapid infusion in future planetary science missions by developing custom SERS substrates tailored towards Venus atmospheric exploration. We have developed SERS substrates consisting of nanotextured silver films and tested them on potential Venus-relevant organic compounds, with preliminary results indicating sub-ppm sensitivity. Additionally, we have planned tests to investigate durability, longevity, and other key characteristics that impact SERS substrate performance to prepare SERS technology for flight.

Venus↗
NASA NTRS2006

Understanding Surface Processes on Mars Through Study of Iron Oxides/Oxyhydroxides: Clues to Surface Alteration and Aqueous Processes

We are performing oxidation and reduction reactions on hydrated ferric oxide minerals in order to investigate how these might alter under a variety of conditions on the surface of Mars. Preliminary experiments on ferrihydrite and goethite showed that heating these minerals in a dry oxidizing environment produces fine-grained hematite, while heating these minerals in a reducing environment produces fine-grained magnetite. Under Mars-like oxidation levels this magnetite then oxidizes to maghemite. These reactions are dependent on the presence of water and organic material that can act as a reductant. We are using reflectance and Mossbauer spectroscopy to characterize the reaction products and TEM to analyze the sample texture. Our preliminary results indicate that magnetite and maghemite could be formed in the soil on Mars from ferrihydrite and goethite if organics were present on early Mars.

Bishop, J. L.↗
NASA NTRS2012

Organic Combustion in the Presence of Ca-Carbonate and Mg-Perchlorate: A Possible Source for the Low Temperature CO2 Release Seen in Mars Phoenix Thermal and Evolved Gas Analyzer Data

Two of the most important discoveries of the Phoenix Lander were the detection of approx.0.6% perchlorate [1] and 3-5% carbonate [2] in landing site soils. The Thermal and Evolved Gas Analyzer (TEGA) instrument on the Phoenix lander could heat samples up to approx.1000 C and monitor evolved gases with a mass spectrometer. TEGA detected a low (approx.350 C) and high (approx.750 C) temperature CO2 release. The high temp release was attributed to the thermal decomposition of Ca-carbonate (calcite). The low temperature CO2 release could be due to desorption of CO2, decomposition of a different carbonate mineral, or the combustion of organic material. A new hypothesis has also been proposed that the low temperature CO2 release could be due to the early breakdown of calcite in the presence of the decomposition products of certain perchlorate salts [3]. We have investigated whether or not this new hypothesis is also compatible with organic combustion. Magnesium perchlorate is stable as Mg(ClO4)2-6H2O on the martian surface [4]. During thermal decomposition, this perchlorate salt releases H2O, Cl2, and O2 gases. The Cl2 can react with water to form HCl which then reacts with calcite, releasing CO2 below the standard thermal decomposition temperature of calcite. However, when using concentrations of perchlorate and calcite similar to what was detected by Phoenix, the ratio of high:low temperature CO2 evolved is much larger in the lab, indicating that although this process might contribute to the low temp CO2 release, it cannot account for all of it. While H2O and Cl2 cause calcite decomposition, the O2 evolved during perchlorate decomposition can lead to the combustion of any reduced carbon present in the sample [5]. We investigate the possible contribution of organic molecules to the low temperature CO2 release seen on Mars.

Archer, Douglas↗
NASA NTRS1988

Iodine sorption study on the proposed use of Viton A in a shuttle galley water accumulator

The installation of a Viton A accumulator in the Shuttle galley has been proposed to prevent overpressurization of the hot water supply system. A laboratory study has been conducted to determine if there would be any interaction between the Viton A material and the iodine used to disinfect the water. Coupons of Viton A were exposed for 24 hours to aqueous iodine solutions similar in quality to the Shuttle's potable water. Changes in the iodine residual were monitored to determine the rate of iodine sorption by the coupon. Total organic carbon (TOC) was monitored to determine the rate of desorption of organic materials from the Viton A. The same coupons were then soaked in reagent-grade water for 24 hours, and iodine was monitored to determine the rate of iodine desorption. The coupons were again exposed to iodine solutions for 24 hours and iodine and TOC were monitored. No significant change in the iodine sorption rate was detected between the first and second exposures. A triangle taste test indicated at a 1 percent confidence level that the water exposed to Viton A had a different taste which was less acceptable to the panelists.

Gibbons, Randall E.↗
NASA NTRS2013

Mineralogy and Elemental Composition of Wind Drift Soil at Rocknest, Gale Crater

The Mars Science Laboratory rover Curiosity has been exploring Mars since August 5, 2012, conducting engineering and first-time activities with its mobility system, arm, sample acquisition and processing system (SA/SPaH-CHIMRA) and science instruments. Curiosity spent 54 sols at a location named "Rocknest," collecting and processing five scoops of loose, unconsolidated materials ("soil") acquired from an aeolian bedform (Fig. 1). The Chemistry and Mineralogy (CheMin) instrument analyzed portions of scoops 3, 4, and 5, to obtain the first quantitative mineralogical analysis of Mars soil, and to provide context for Sample Analysis at Mars (SAM) measurements of volatiles, isotopes and possible organic materials.

Blake, D. F.↗
NASA NTRS2011

LIFE: Enceladus Sample Return Mission Concept for Searching Evidence of Life

One of the most promising targets for the search for life other than Mars in our Solar System is the tiny Saturn moon Enceladus. The Cassini mission to the Saturian system detected an active region on Enceladus where small water particles and gas containing organic materials were being flung into space from a region near the south pole known as the tiger stripes. This discovery indicated that there is very likely a liquid subsurface ocean heated through tidal interactions as Enceladus orbits Saturn. On Earth, whenever there is an energy source, liquid water and organics, there is life; this makes Enceladus one of the prime candidates for a search for life missions. In this presentation, we describe LIFE (Life Investigation For Enceladus) sample return concept from Enceladus in the search for evidence of life.

Enceladus↗
NASA NTRS2009

NASA Engineering and Safety Center Technical Bulletin No. 09-05: Self-Contained Oxygen Generator: Effects of Organic Contamination, Briquette Fracturing, Pressure Containment, and Variations in Chemical Composition

A Self-Contained Oxygen Generator (SCOG) produces breathable oxygen (O 2 ) by using chemically-reactive briquettes that begin producing O 2 when mechanically ignited. Contamination with organic material of, or manufacturing defects in, the briquettes have been shown to lead to conditions that can cause an explosive failure

Self Contained Oxygen Generator↗
NASA NTRS1987

Low temperature hydrothermal maturation of organic matter in sediments from the Atlantis II Deep, Red Sea

Hydrocarbons and bulk organic matter of two sediment cores within the Atlantis II Deep are analyzed, and microbial inputs and minor terrestrial sources are found to represent the major sedimentary organic material. Results show that extensive acid-catalyzed reactions are occurring in the sediments, and the Atlantis II Deep is found to exhibit a lower degree of thermal maturation than other hydrothermal or intrusive systems. The lack of carbon number preference noted among the n-alkanes suggests that the organic matter of these sediments has undergone some degree of catagenesis, though yields of hydrocarbons are much lower than those found in other hydrothermal areas, probably due to the effect of lower temperature and poor source-rock characteristics.

Simoneit, Bernd R. T.↗
NASA NTRS2003

Complex Organics from Laboratory Simulated Interstellar Ices

Many of the volatiles in interstellar dense clouds exist in ices surrounding dust grains. The low temperatures of these ices (T < 50 K) preclude most chemical reactions, but photolysis can drive reactions that produce a suite of new species, many of which are complex organics. We study the UV and proton radiation processing of interstellar ice analogs to explore links between interstellar chemistry, the organics in comets and meteorites, and the origin of life on Earth. The high D/H ratios in some interstellar species, and the knowledge that many of the organics in primitive meteorites are D-enriched, suggest that such links are plausible. Once identified, these species may serve as markers of interstellar heritage of cometary dust and meteorites. Of particular interest are our findings that UV photolysis of interstellar ice analogs produce molecules of importance in current living organisms, including quinones, amphiphiles, and amino acids. Quinones are essential in vital metabolic roles such as electron transport. Studies show that quinones should be made wherever polycyclic aromatic hydrocarbons are photolyzed in interstellar ices. In the case of anthracene-containing ices, we have observed the production of 9-anthrone and 9,10 anthraquinone, both of which have been observed in the Murchison meteorite. Amphiphiles are also made when mixed molecular ices are photolyzed. These amphiphiles self-assemble into fluorescent vesicles when placed in liquid water, as do Murchison extracts. Both have the ability to trap an ionic dye. Photolysis of plausible ices can also produce alanine, serine, and glycine as well as a number of small alcohols and amines. Flash heating of the room temperature residue generated by such experiments generates mass spectral distributions similar to those of IDPs. The detection of high D/H ratios in some interstellar molecular species, and the knowledge that many of the organics, such as hydroxy and amino acids, in primitive meteorites are D-enriched provides evidence for a connection between intact organic material in the interstellar medium and in meteorites. Thus, some of the oxidized aromatics, amphiphiles, amino acids, hydroxy acids, and other compounds found in meteorites may have had an interstellar ancestry and not solely a product of parent body aqueous alteration. Such compounds should also be targeted for searches of organics in cometary dust.

Dworkin, J. P.↗
DOE OSTI2022

Spin injection by spin–charge coupling in proximity induced magnetic graphene

Abstract Within the field of spintronics major efforts are directed towards developing applications for spin-based transport devices made fully out of two-dimensional materials. In this work we present an experimental realization of a spin-valve device where the generation of the spin signal is exclusively attributed to the spin-dependent conductivity of the magnetic graphene resulting from the proximity of an interlayer antiferromagnet, chromium sulfide bromide (CrSBr). We clearly demonstrate that the usage of the conventional air-sensitive 3D magnetic contacts can be fully avoided when graphene/CrSBr heterostructures are employed. Moreover, apart from providing exceptionally long spin relaxation length, the usage of graphene for both generation and transport of the spin allows to automatically avoid the conductivity mismatch between the source and the channel circuits that has to be considered when using conventional low-resistive contacts. Our results address a necessary step in the engineering of spintronic circuitry out of layered materials and precede further developments in the area of complex spin-logic devices. Moreover, we introduce a fabrication procedure where we designed and implemented a recipe for the preparation of electrodes via a damage-free technique that offers an immediate advantage in the fields of air-sensitive and delicate organic materials.

36 MATERIALS SCIENCE↗
NASA NTRS1983

U.S. planetary protection program - Implementation highlights

The implementation of the United States planetary protection program, intended to prevent the contamination of the celestial bodies in the solar system during their exploration, in recent interplanetary projects is reviewed. The shift in planetary protection policy from that of absolute sterilization to a probabilistic approach is noted. Attention is then given to the use of microbiological assay, organic materials inventory, microbial burden reduction, contamination control, trajectory biasing and the analysis and identification of contaminating processes for purposed of planetary protection for the Pioneer 10 and 11, Viking and Voyager projects. The success of these measures, as demonstrated by the prevention of accidental planetary impact and the failure to detect terrestrial organisms by the Viking life detection experiments, is pointed out.

Barengoltz, J.↗
NASA NTRS1987

Polymer crystal growth facility concept for Space Station laboratory module

Interest in materials processing in space began to evolve in the late 1950's through low gravity simulation and some experiments on Apollo flights. Encouraged by the early results and considerations of the likely behavior of liquids and solidification process in low-gravity gave the recognition that this environment might be useful for a variety of unique processes. This generated a number of experimental ideas and gave rise to the design and development of facilities that will perform the experiments in space vehicles. These include the evolution of apparatus leading to the development of facilities for processing of materials on Skylab and now for the Space Transportation System (STS). The U.S. module on Space Station (SS) is going to expand this unique laboratory environment with practically no constraint on materials processing activity. This will need technology advancement for the hardware that will be required in this era. This presentation discusses the current concept for the experimental facility which will be housed in the U.S. Laboratory module on the Space Station and will allow the growth of single crystals of polymeric and organic materials using the state-of-the-art growth techniques.

Mookherji, Tripty↗
NASA NTRS2011

Origin and Evolution of Prebiotic Organic Matter as Inferred from the Tagish Lake Meteorite

The complex suite of organic materials in carbonaceous chondrite meteorites probably originally formed in the interstellar medium and/or the solar protoplanetary disk, but was subsequently modified in the meteorites' asteroidal parent bodies. The mechanisms of formation and modification are still very poorly understood. We carried out a systematic study of variations in the mineralogy, petrology, and soluble and insoluble organic matter in distinct fragments of the Tagish Lake meteorite. The variations correlate with indicators of parent body aqueous alteration and at least some molecules of pre-biotic importance formed during the alteration.

Herd, Christopher D.↗
DOE OSTI2024

Machine learning for the redox potential prediction of molecules in organic redox flow battery

Here, organic redox flow batteries (ORFB) are recognized as an innovative technology for the large-scale storage of renewable energy. The redox potential of organic redox-active molecules plays a vital role in their performance. Advanced screening techniques like high-throughput experiment and machine learning (ML) have significantly enhanced organic material performance and transformed the field of ORFB. However, the scarcity of experimental data poses a considerable challenge for ML model development in this domain. In our study, we developed lightweight graph-based Gaussian process regression (GPR) models with GPU-accelerated marginalized graph kernel and hybrid kernel to predict the redox potentials of organic redox-active molecules for ORFBs, specifically focusing on small datasets. To evaluate model accuracy, we created a new experimental database of organic redox-active molecules by the data from hundreds of published papers and assembled previous computational datasets. We also considered some key parameters, such as pH conditions and solvent type, to assess their impact on redox potential prediction. Our GPR model predicted redox potentials with high accuracy across all datasets using minimal training data. The study provides powerful tools for molecule screening and design and delivers valuable guidance on designing training datasets for costly experiments.

25 ENERGY STORAGE↗
DOE OSTI2022

High-Accuracy Semiempirical Quantum Models Based on a Minimal Training Set

A great need exists for computationally efficient quantum simulation approaches that can achieve an accuracy similar to high-level theories at a fraction of the computational cost. In this regard, we have leveraged a machine-learned interaction potential based on Chebyshev polynomials to improve density functional tight binding (DFTB) models for organic materials. The benefit of our approach is two-fold: (1) many-body interactions can be corrected for in a systematic and rapidly tunable process, and (2) high-level quantum accuracy for a broad range of compounds can be achieved with ~0.3% of data required for one advanced deep learning potential. Our model exhibits both transferability and extensibility through comparison to quantum chemical results for organic clusters, solid carbon phases, and molecular crystal phase stability rankings. Overall, our efforts thus allow for high-throughput physical and chemical predictions with up to coupled-cluster accuracy for systems that are computationally intractable with standard approaches.

36 MATERIALS SCIENCE↗