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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

Compact and Lightweight Sabatier Reactor for Carbon Dioxide Reduction

The utilization of CO2 to produce life support consumables, such as O2 and H2O, via the Sabatier reaction is an important aspect of NASA s cabin Atmosphere Revitalization System and In-Situ Resource Utilization architectures for both low-earth orbit and long-term manned space missions. In the current International Space Station (ISS) and other low orbit missions, metabolically-generated CO2 is removed from the cabin air and vented into space, resulting in a net loss of O2. This requires a continuous resupply of O2 via water electrolysis, and thus highlights the need for large water storage capacity. For long-duration space missions, the amount of life support consumables is limited and resupply options are practically nonexistent, thus atmosphere resource management and recycle becomes crucial to significantly reduce necessary O2 and H2O storage. Additionally, the potential use of the Martian CO2-rich atmosphere and Lunar regolith to generate life support consumables and propellant fuels is of interest to NASA. Precision Combustion, Inc. (PCI) has developed a compact, lightweight Microlith(Registered TradeMark)-based Sabatier (CO2 methanation) reactor which demonstrates the capability of achieving high CO2 conversion and near 100% CH4 selectivity at space velocities of 30,000-60,000 hr-1. The combination of the Microlith(Registered TradeMark) substrates and durable, novel catalyst coating permitted efficient Sabatier reactor operation that favors high reactant conversion, high selectivity, and long-term durability. This paper presents the reactor development and performance results at various operating conditions. Additionally, results from 100-hr durability tests and mechanical vibration tests are discussed.

Junaedi, Christian↗
NASA NTRSDate not supplied

Pyrolysis Rate and Yield Strength Reduction in Carbon Fiber and Glass Fiber Composites under Reentry Heating Conditions

The behavior of composite materials, specifically carbon fiber-reinforced polymer (CFRP) and glass fiber-reinforced polymer (GFRP), under re-entry conditions poses a problem for orbital debris re-entry risk modeling. Since these materials pyrolyze rather than melt and their different components demise at different rates, modeling their destruction to determine ground impact risk is complex. Modern spacecraft are using these materials in ever-greater quantities owing to their superior strength-to -weight characteristics, and this has required that the orbital debris community improve its understanding of how these materials demise on re-entry.

Benton R Greene↗
NASA NTRS1977

The effect of carbon on phosphate reduction

Several experiments were performed in order to evaluate the effect of carbon on phosphate reduction in synthetic systems. It was attempted to simulate in the experiments conditions occurring during lunar impact processes, but without shock pressure. Temperature, oxygen fugacity, and bulk chemistry were evaluated separately in order to determine the conditions which are suitable for carbon reduction. It appears on the basis of the results of the reported investigation that carbon can be an effective reducing agent during reheating events such as those encountered by lunar soils and breccias. Phosphate reduction may be viewed as a two-step process in which carbon is mobilized as CO during heating and preferentially dissolved in the metal phase. It then acts as a reducing agent on cooling. Gas phase transport and diffusion of carbon in metal are sufficiently rapid to allow uniform carbon distribution both within and between metal grains. The availability of metal from meteorites and carbon from the solar wind is probably sufficient to make reduction by carbon a significant process on the lunar surface.

Friel, J. J.↗
NASA NTRS1976

Thermogravimetric study of reduction of oxides present in oxidized nickel-base alloy powders

Carbon, hydrogen, and hydrogen plus carbon reduction of three oxidized nickel-base alloy powders (a solid solution strengthened alloy both with and without the gamma prime formers aluminum and titanium and the solid solution strengthened alloy NiCrAlY) were evaluated by thermogravimetry. Hydrogen and hydrogen plus carbon were completely effective in reducing an alloy containing chromium, columbium, tantalum, molybdenum, and tungsten. However, with aluminum and titanium present the reduction was limited to a weight loss of about 81 percent. Carbon alone was not effective in reducing any of the alloys, and none of the reducing conditions were effective for use with NiCrAlY.

Herbell, T. P.↗
NASA NTRS1978

High-purity silicon for solar cell applications

The article discusses the production of solar cells from high-purity silicon. The process consists of reducing the level of impurities in the raw materials, preventing material contamination before and after entering the furnace, and performing orders-of-magnitude reduction of metal impurity concentrations. The high-purity raw materials are considered with reference to carbon reductants, silica, and graphite electrodes. Attention is also given to smelting experiments used to demonstrate, in an experimental-scale furnace, the production of high-purity SoG-Si. It is found that high-purity silicon may be produced from high-purity quartz and chemically purified charcoal in a 50-kVA arc furnace. The major contamination source is shown to be impurities from the carbon reducing materials.

Dosaj, V. D.↗
NASA NTRS1977

Silicon material task. Part 3: Low-cost silicon solar array project

The feasibility of a process for carbon reduction of low impurity silica in a plasma heat source was investigated to produce low-cost solar-grade silicon. Theoretical aspects of the reaction chemistry were studied with the aid of a computer program using iterative free energy minimization. These calculations indicate a threshold temperature exists at 2400 K below which no silicon is formed. The computer simulation technique of molecular dynamics was used to study the quenching of product species.

Roques, R. A.↗
NASA NTRS1985

The problem of the Earth's CO2 content and the iron core

The near absence of metallic iron and the presence of magnetite and FeS in the C-1 chondrites imply that metallic iron was a minor phase present during the accretion process that formed the C-1 chondrites. If the C-1 chondrites provided the bulk of the initial planetary growth materials, the carbon reduction model is favored. The above estimates suggest that some 1240 to 227 times as much CO2 may have been produced during the formation of the core than can be accounted for in the crust and mantle. This discrepancy taken to the extreme suggests either that: (1) the Earth has lost more than 99 percent of its initial CO2 during early differentiation (this is highly unlikely) or: (2) the Earth has acquired some 90 percent of its present mass by the accretion of debris from previously reduced and differentiated but subsequently disrupted planetary bodies whereby the associated CO2 would not be captured, or: (3) the C-1 chondrites represent only a trivial fraction of the initial accretion materials present in the nebular cloud or: (4) condensed iron and anhydrous silicate phases were preferentially accreted during the initial formation of the planetary bodies.

Devore, G. W.↗
NASA NTRS1989

Refurbishment of one-person regenerative air revitalization system

Regenerative processes for the revitalization of spacecraft atmospheres and reclamation of waste waters are essential for making long-term manned space missions a reality. Processes studied include: static feed water electrolysis for oxygen generation, Bosch carbon dioxide reduction, electrochemical carbon dioxide concentration, vapor compression distillation water recovery, and iodine monitoring. The objectives were to: provide engineering support to Marshall Space Flight Center personnel throughout all phases of the test program, e.g., planning through data analysis; fabricate, test, and deliver to Marshall Space Flight Center an electrochemical carbon dioxide module and test stand; fabricate and deliver an iodine monitor; evaluate the electrochemical carbon dioxide concentrator subsystem configuration and its ability to ensure safe utilization of hydrogen gas; evaluate techniques for recovering oxygen from a product oxygen and carbon dioxide stream; and evaluate the performance of an electrochemical carbon dioxide concentrator module to operate without hydrogen as a method of safe haven operation. Each of the tasks were related in that all focused on providing a better understanding of the function, operation, and performance of developmental pieces of environmental control and life support system hardware.

Powell, Ferolyn T.↗
NASA NTRS1991

Oxygen isotope studies of ordinary chondrites

Several stages in the evolution of ordinary chondritic meteorites are recorded in the oxygen isotopic composition of the meteorites and their separable components (chondrules, fragments, clasts, and matrix). The whole-rock isotopic compositions reflect the iron-group of the meteorite (H, L, or LL). Isotopic uniformity of H3 to H6 and L3 to L6 are consistent with closed-system metamorphism within each parent body. LL3 chondrites differ slightly from LL4 to LL6, implying a small degree of open-system aqueous alteration and carbon reduction. On the scale of individual chondrules, the meteorites are isotopically heterogeneous, allowing recognition of the solar-nebular processes of chondrule formation. Chondrules for all classes of ordinary chondrites are derived from a common population, which was separate from the population of chondrules in carbonaceous or enstatite chondrites. Chondrules define an isotopic mixing line dominated by exchange between (O - 16)-rich and (O - 16)-poor reservoirs. The oxygen isotopic compositions of chondrites serve as 'fingerprints' for identification of genetic association with other meteorite types (achondrites and iron) and for recognition of source materials in meteoritic breccias.

Clayton, Robert N.↗
NASA NTRS1992

Assessment of the state of the art in life support environmental control for SEI

This paper defines the types of technology that would be used in a lunar base for environmental control and life support system and how it might relate to in situ materials utilization (ISMU) for the Space Exploration Initiative (SEI). There are three types of interaction between ISMU and the Environmental Control and Life Support System (ECLSS): (1) ISMU can reduce cost of water, oxygen, and possibly diluent gasses provided to ECLSS--a corollary to this fact is that the availability of indigenous resources can dramatically alter life support technology trade studies; (2) ISMU can use ECLSS waste systems as a source of reductant carbon and hydrogen; and (3) ECLSS and ISMU, as two chemical processing technologies used in spacecraft, can share technology, thereby increasing the impact of technology investments in either area.

Simonds, Charles H.↗
NASA NTRS2001

Thiols in Hydrothermal Solution: Standard Partial Molal Properties and Their Role in the Organic Geochemistry of Hydrothermal Environments

Modern seafloor hydrothermal systems are locations where great varieties of geochemistry occur due to the enormous disequilibrium between vent fluids and seawater. The disequilibrium geochemistry has been hypothesized to include reactions to synthesize organic compounds. Despite the incomplete understanding of the carbon budget in hydrothermal systems, the organic geochemistry of these sites has received little attention. Experimental simulations of these environments, however, indicate that organic compounds may have difficulty forming in a purely aqueous environment. On the other hand, thiols, thioesters and disulfides have been implicated as reaction intermediates between CO or CO2 in experiments of carbon reduction in hydrothermal environments, as well as in a variety of biological processes and other abiotic reactions. The reduction of CO2 to thesis, for example, is observed using the FeS-H2S/FeS2 couple to provide the reducing power. We have used recent advances in theoretical geochemistry to estimate the standard partial moral thermodynamic properties and parameters for the revised Helgeson-Kirkham-Flowers equation of state for aqueous straight-chain alkyl thesis. With these data and parameters we have evaluated the role that organic sulfur compounds may play as reaction intermediates during organic compound synthesis. We conclude that organic sulfur compounds may hold the key to the organic chemistry leading to the origin of life in hydrothermal settings. These results may also explain the presence of sulfur in a number of biomolecules present in ancient thermophilic microorganisms.

Schulte, Mitchell D.↗
NASA NTRS1995

A Biochemical Magic Frequency Based on the Reduction Level of Biological Carbon

We have calculated the average number of electron pairs required for the chemical reduction of carbon dioxide to biological carbon using (a) estimates of the reducing equivalents (electron pairs) needed to synthesize biomolecules from carbon dioxide, and (b) measurements of the molecular composition of different organisms. These calculations showed that the carbon of the Earth's biosphere is at the reduction level of formaldehyde that requires two electron pairs per carbon atom to be synthesized from carbon dioxide. This was also the reduction level of cellular carbon when fuel stored as lipid was not used in the estimate. Since this chemical characteristic of life is probably universal, it could be the one thing we know about other carbon-based life in the universe, and the one thing that other intelligent life knows about us. We believe that this common knowledge that biological carbon throughout the universe is at the reduction level of formaldehyde could lead to the selection of the 72.83814 GHz line of the 0, 0, 0 yields 1, 1, 1 rotational transition of formaldehyde as a frequency for interstellar communication.

Weber, Arthur L.↗
NASA NTRS2018

Quantified, Localized Health Benefits of Accelerated Carbon Dioxide Emissions Reductions

Societal risks increase as Earth warms, and increase further for emissions trajectories accepting relatively high levels of near-term emissions while assuming future negative emissions will compensate, even if they lead to identical warming as trajectories with reduced near-term emissions. Accelerating carbon dioxide (CO2) emissions reductions, including as a substitute for negative emissions, hence reduces long-term risks but requires dramatic near-term societal transformations. A major barrier to emissions reductions is the difficulty of reconciling immediate, localized costs with global, long-term benefits. However, 2 C trajectories not relying on negative emissions or 1.5 C trajectories require elimination of most fossil-fuel-related emissions. This generally reduces co-emissions that cause ambient air pollution, resulting in near-term, localized health benefits. We therefore examine the human health benefits of increasing 21st-century CO2 reductions by 180 GtC, an amount that would shift a 'standard' 2 C scenario to 1.5 C or could achieve 2 C without negative emissions. The decreased air pollution leads to 153 +/- 43 million fewer premature deaths worldwide, with approx.40% occurring during the next 40 years, and minimal climate disbenefits. More than a million premature deaths would be prevented in many metropolitan areas in Asia and Africa, and greater than 200,000 in individual urban areas on every inhabited continent except Australia.

Atmospheric science↗
NASA NTRS1978

Determination of carbon by the oxidation reduction reaction with chromium

Free carbon was determined in silicon and boron carbides in ash, oxides, and other materials by oxidation to carbon dioxide with a mixture of K2Cr2O7 + H2SO4. The determination was made from the amount of CR(6) consumed, by adding excess Mohr's salt and titrating with a standard solution of KMnO4. The amount of Cr(6) self reduced was determined in a blank test. Optimum oxidation and conditions were achieved when the volumes of 5% k2Cr2Oz and H2SO4 were equal. The mixture was boiled for 1-2 hours using a reflex condenser. The volume should not be reduced, in order to avoid an increase in the sulfuric acid concentration. The relative error was 4-7% for 0.005-0.04 g C and less than or equal to 3.5% for 0.1 g C.

Mashkovich, L.↗
NASA NTRS2017

Oxygen Extraction from Minerals

Oxygen, whether used as part of rocket bipropellant or for astronaut life support, is a key consumable for space exploration and commercialization. In Situ Resource Utilization (ISRU) has been proposed many times as a method for making space exploration more cost effective and sustainable. On planetary and asteroid surfaces the presence of minerals in the regolith that contain oxygen is very common, making them a potential oxygen resource. The majority of research and development for oxygen extraction from minerals has been for lunar regolith although this work would generally be applicable to regolith at other locations in space. This presentation will briefly survey the major methods investigated for oxygen extraction from regolith with a focus on the current status of those methods and possible future development pathways. The major oxygen production methods are (1) extraction from lunar ilmenite (FeTiO3) with either hydrogen or carbon monoxide, (2) carbothermal reduction of iron oxides and silicates with methane, and (3) molten regolith electrolysis (MRE) of silicates. Methods (1) and (2) have also been investigated in a two-step process using CO reduction and carbon deposition followed by carbothermal reduction. All three processes have byproducts that could also be used as resources. Hydrogen or carbon monoxide reduction produce iron metal in small amounts that could potentially be used as construction material. Carbothermal reduction also makes iron metal along with silicon metal and a glass with possible applications. MRE produces iron, silicon, aluminum, titanium, and glass, with higher silicon yields than carbothermal reduction. On Mars and possibly on some moons and asteroids, water is present in the form of mineral hydrates, hydroxyl (-OH) groups on minerals, andor water adsorbed on mineral surfaces. Heating of the minerals can liberate the water which can be electrolyzed to provide a source of oxygen as well. The chemistry of these processes, some key development and demonstration projects, the challenges remaining to be overcome, and possible future directions will be discussed with a goal of increased understanding of these important ISRU technologies and their potential applications to space exploration and settlement.

propellant production↗