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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 559 records · Page 31
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

In Situ Measurements of the ClO/HCl Ratio: Heterogeneous Processing on Sulfate Aerosols and Polar Stratospheric Clouds

Simultaneous in situ measurements of stratospheric ClO and HCl have been made for the first time, during numerous flights of the ER-2 aircraft covering latitudes 24-90 deg. N from October 1991 through March 1992. The ClO/HCl ratio is identified as a key indicator of heterogeneous processing both outside and within the Arctic polar vortex. For ClO mixing ratios below about 120 pptv, remarkably constant ClO/HCl values of about 15% characterize the lower stratosphere. The observed values are significantly higher than those derived from a 2-D model using either gas phase photochemistry alone (2%), or including heterogeneous sulfate chemistry (5-10%). During the Arctic early spring, after conversion of HCl into reactive chlorine has taken place, the vortex edge is poorly defined by ClO levels. Loss of HCl and its slow recovery following low-temperature polar heterogeneous chemistry distinguishes HCl as a new and unique dynamical tracer of PSC-processed air.

Webster, C. R.↗
NASA NTRS1993

In Situ Measurements of the ClO/HCl Ratio: Heterogeneous Processing on Sulfate Aerosols and Polar Stratospheric Clouds

Simultaneous in situ measurements of stratospheric ClO and HCl have been made for the first time, during numerous flights of the ER-2 aircraft covering latitudes 24-90 deg N from October 1991 through March 1992. The ClO/HCl ratio is identified as a key indicator of heterogeneous processing both outside and within the Arctic polar vortex. For ClO mixing ratios below about 120 pptv, remarkably constant ClO/HCl values of about 15% characterize the lower stratosphere. The observed values are significantly higher than those derived from a 2-D model using either gas phase photochemistry alone (2%), or including heterogeneous sulfate chemistry (5-10%). During the Arctic early spring, after conversion of HCl into reactive chlorine has taken place, the vortex edge is poorly defined by ClO levels. Loss of HCl and its slow recovery following low-temperature polar heterogeneous chemistry distinguishes HCl as a new and unique dynamical tracer of PSC-processed air.

Webster, C. R.↗
NASA NTRS1996

Development of a High-Resolution, Single-Photon X-Ray Detector

Research on the development of a low-temperature, magnetic bolometer for x-ray detection is reported. The principal accomplishments during the first phase of this research are as follows. (1) We have constructed SQUID magnetometers and detected both 122 keV and 6 keV x-rays in relatively larger metallic samples with high quantum efficiency. (2) The magnetic properties of a metal sample with localized paramagnetic spins have been measured and found to agree with theoretical expectations. (3) The size of the magnetic response of the sample to x-rays is in agreement with predictions based on the properties of the sample and sensitivity of the magnetometer, supporting the prediction that a resolution of 1 eV at 10 keV should be achievable.

Seidel, George M.↗
NASA NTRS1997

Sulfur and Hydrogen Isotope Anomalies in Meteorite Sulfonic Acids

Intramolecular carbon, hydrogen, and sulfur isotope ratios were measured on a homologous series of organic sulfonic acids discovered in the Murchison meteorite. Mass-independent sulfur isotope fractionations were observed along with high deuterium/hydrogen ratios. The deuterium enrichments indicate formation of the hydrocarbon portion of these compounds in a low-temperature environment that is consistent with that of interstellar clouds. Sulfur-33 enrichments observed in methanesulfonic acid could have resulted from gas-phase ultraviolet irradiation of a precursor, carbon disulfide. The source of the sulfonic acid precursors may have been the reactive interstellar molecule carbon monosulfide.

Cooper, George W.↗
NASA NTRS1995

The Origin of Life--Did It Occur at High Temperatures

A high-temperature origin of life has been proposed, largely for the reason that the hyperthermophiles are claimed to be the last common ancestor of modern organisms. Even if they are the oldest extant organisms, which is in dispute, their existence can say nothing about the temperatures of the origin of life, the RNA world, and organisms preceding the hyperthermophiles. There is no geological evidence for the physical setting of the origin of life because there are no unmetamorphosed rocks from that period. Prebiotic chemistry points to a low-temperature origin because most biochemicals decompose rather rapidly at temperatures of 100 C (e.g., half-lives are 73 min for ribose, 21 days for cytosine, and 204 days for adenine). Hyperthermophiles may appear at the base of some phylogenetic trees because they outcompeted the mesophiles when they adapted to lower temperatures, possibly due to enhanced production of heat-shock proteins.

Miller, Stanley L.↗
NASA NTRS1960

Equipment for Thermal-Balance Studies in the Langley Instrument Research Division

The Langley Research Center is in the process of obtaining emissivity measuring apparatus. This apparatus will be used to measure the solar absorptance and low-temperature emittance of space-vehicle materials. Two types of instrumentation will be used. One type will be the total hemispherical emissivity apparatus being constructed at this Center. The other will be double-beam photoelectric ratio-recording spectrophotometer apparatus which is being purchased.

Spiers, Robert B., Jr.↗
NASA NTRS1946

Characteristics of a Hot Jet Discharged from a Jet-Propulsion Engine

An investigation of a heated jet was conducted in conjunction with tests of an axial-flow jet-propulsion engine in the Cleveland altitude wind tunnel. Pressure and temperature surveys were made across the jet 10 and 15 feet behind the jet-nozzle outlet of the engine. Surveys were obtained at pressure altitudes of 10,000, 20,000, 30,000, and 40,000 feet with test-section velocities from 30 to 110 feet per second and test-section temperatures from 60 F to -50 F. From measurements taken throughout the operable range of engine speeds, tail-pipe outlet temperatures from 500 F to 1250 F and jet velocities from 400 to 2200 feet per second were obtained. The jet-survey data presented extend the work previously done with low-velocity and low-temperature jets to the region of high velocities and high temperatures. The results obtained agree with previously determined experimental data and with predicted theoretical expressions for the dimensionless transverse velocity and temperature profiles across a jet. The spread of both the temperature and the velocity profiles was very nearly linear. Dimensionless plots of temperature and velocity along the axis of a heated jet agree with experimental results of tests with a cold jet.

Fleming, William A.↗
NASA NTRS1991

Some Recent Studies With the Solid-Ionomer Electrochemical Capacitor

Giner, Inc., has developed a high-energy-density, all-solid-ionomer electro-chemical capacitor, completely free of liquid electrolyte. The novel features of this device include: (1) a three-dimensional metal oxide-particulate-ionomer composite electrode structure and (2) a unitized repeating cell element. The composite electrode structures are bonded to opposite sides of a thin sheet of a solid proton-conducting ionomer membrane and form an integrally bonded membrane and electrode assembly (MEA). Individual MEAs can be stacked in series as bipolar elements to form a multiple cell device. The discharge characteristics and energy storage properties of these devices are described. Typical capacitance measured for a unit cell is 1 F/cm. Life testing of a multicell capacitor on an intermittent basis has shown that, over a 10,000-hour period, the capacitance and resistance of the cell has remained invariant. There has been no maintenance required on the device since it was fabricated. Other multicell units of shorter life duration have exhibited similar reliable performance characteristics. Recent work has focused on increasing the capacitance of the unitized structure and improving the low-temperature characteristics. The approaches and experimental results will be presented. Some possible advanced NASA applications for these unique all-solid-ionomer devices will be discussed.

Sarangapani, S.↗
NASA NTRS1994

New calculations on the ion-molecule processes C2H2(+) + H2 --> C2H3(+) + H and C2H2(+) + H2 --> C2H4+

New high-level quantum chemical calculations have been undertaken to understand the rates and mechanisms of the reactive and associative channels for the reactants C2H2(+) + H2. The reactive channel, which produces C2H3(+) + H, has been shown to be slightly endothermic, confirming earlier calculations at a somewhat lower level and in agreement with some recent experimental work. The associative channel, leading to C2H4+, has been shown to proceed via a transition state with negative energy relative to the reactants, so that association is predicted to be efficient. This result is in conflict with an earlier theoretical study but in agreement with low-temperature experimental measurements.

NASA Discipline Exobiology↗
NASA NTRS1994

Distribution of cultivated and uncultivated cyanobacteria and Chloroflexus-like bacteria in hot spring microbial mats

Oligodeoxynucleotide hybridization probes were developed to complement specific regions of the small subunit (SSU) rRNA sequences of cultivated and uncultivated cyanobacteria and Chloroflexus-like bacteria, which inhabit hot spring microbial mats. The probes were used to investigate the natural distribution of SSU rRNAs from these species in mats of Yellowstone hot springs of different temperatures and pHs as well as changes in SSU rRNA distribution resulting from 1-week in situ shifts in temperature, pH, and light intensity. Synechococcus lividus Y-7c-s SSU rRNA was detected only in the mat of a slightly acid spring, from which it may have been initially isolated, or when samples from a more alkaline spring were incubated in the more acid spring. Chloroflexus aurantiacus Y-400-fl SSU rRNA was detected only in a high-temperature mat sample from the alkaline Octopus Spring or when lower-temperature samples from this mat were incubated at the high-temperature site. SSU rRNAs of uncultivated species were more widely distributed. Temperature distributions and responses to in situ temperature shifts suggested that some of the uncultivated cyanobacteria might be adapted to high-, moderate-, and low-temperature ranges whereas an uncultivated Chloroflexus-like bacterium appears to have broad temperature tolerance. SSU rRNAs of all uncultivated species inhabiting a 48 to 51 degrees C Octopus Spring mat site were most abundant in the upper 1 mm and were not detected below a 2.5-to 3.5-mm depth, a finding consistent with their possible phototrophic nature. However, the effects of light intensity reduction on these SSU rRNAs were variable, indicating the difficulty of demonstrating a phototrophic phenotype in light reduction experiments.

Non-NASA Center↗
NASA NTRS1997

Organic synthesis in experimental impact shocks

Laboratory simulations of shocks created with a high-energy laser demonstrate that the efficacy of organic production depends on the molecular, not just the elemental composition of the shocked gas. In a methane-rich mixture that simulates a low-temperature equilibrium mixture of cometary material, hydrogen cyanide and acetylene were produced with yields of 5 x 10(17) molecules per joule. Repeated shocking of the methane-rich mixture produced amine groups, suggesting the possible synthesis of amino acids. No organic molecules were produced in a carbon dioxide-rich mixture, which is at odds with thermodynamic equilibrium approaches to shock chemistry and has implications for the modeling of shock-produced organic molecules on early Earth.

NASA Discipline Exobiology↗
NASA NTRS1994

Record of fluid-rock interactions on Mars from the meteorite ALH84001

Allan Hills (ALH) 84001 is the most recently recognized member of a suite of meteorites--the SNCs--that almost certainly originated on Mars. Several factors distinguish ALH84001 from the other SNC meteorites. Preliminary studies suggest that it may be older than other martian meteorites. Moreover, it contains abundant, zoned domains of calcium-iron-magnesium carbonate that are indigenous to the sample and thus may hold important clues regarding near-surface processes on Mars and the evolution of the martian atmosphere. We report here analyses of the carbon and oxygen stable-isotope compositions of the carbonates that place constraints on their formation conditions. Our results imply the presence of at least two chemically distinct carbonates--one Ca,Fe-rich, the other Mg-rich--that are enriched in 13C relative to terrestrial carbonates (delta 13C approximately +41/1000), consistent with martian atmospheric CO2 as the carbon source. The oxygen isotope compositions of the carbonates indicate that they precipitated from a low-temperature fluid in the martian crust. Combined with textural and bulk geochemical considerations, the isotope data suggest that carbonate deposition took place in an open-system environment in which the ambient temperature fluctuated.

Carbonates/analysis↗
NASA NTRS1996

Source of Scatter in the Creep Lives of NiAl(Hf) Single Crystals Revealed

In recent years, there has been an increased emphasis in developing NiAl-based alloys for high- temperature applications in aircraft engines. In comparison to commercial superalloys, binary NiAl has a higher melting temperature, lower density, larger thermal conductivity, and better oxidation resistance. These properties make it a desirable material to replace superalloys as blades and vanes in aircraft engines. Despite this attractive combination of properties, binary NiAl cannot be used as a reliable structural material because of its low-temperature brittleness and poor high-temperature creep strength. GE Aircraft Engines in Cincinnati, Ohio, has recently developed NiAl(Hf) alloys that have creep strengths comparable to commercial superalloys while maintaining the other desirable properties of binary NiAl. The microstructures of these alloys consist of finely distributed G-phase (Ni_(16)Hf_(6)Si_(7)) precipitates, which strengthen the NiAl matrix. However, while the creep properties of these alloys were being evaluated, considerable scatter was observed in the creep lives of specimens tested under identical stress and temperature conditions. Although these alloys had nominally the same composition, the test specimens were obtained from four different ingots (A, B, C, and D) that had been heat treated under similar conditions. The NASA Lewis Research Center began the present study at the request of GE Aircraft Engines under a Space Act Agreement to identify the source of this scatter.

Source record↗
NASA NTRS1960

A Solid Film Lubricant Composition for Use at High Sliding Velocities in Liquid Nitrogen

Solid-lubricant-containing compositions can be of value as films and solid bodies for bearing and seal surfaces in low-temperature liquefied gases. An experimental composition including polytetrafluoroethylene (PTFE), an epoxy resin, and lithium-alumina-silicate was studied in friction, wear, and endurance experiments in liquid nitrogen (−320 F). This composition was formulated to approximate the thermal expansion of metals used in cryogenic systems. Hemisphere (3/6-in. radius) rider specimens were used and in most experiments the load was 1000 g. Films (0.005-in. thick) on disk specimens gave good endurance life, low rider wear, and desirable friction (f = 0.02 to 0.07). They functioned at a higher sliding velocity (no failure at 16, 000 ft/min) with copper rider specimens than with stainless steel riders (failure at 9000 ft/min). Solid rider material of the experimental composition had good friction and wear properties at sliding velocities above 4000 ft/min. It is important to use the experimental composition with mating materials having good thermal conductivity.

Wisander, D. W.↗
NASA NTRS2026

Molecular Inventory and Comparative Organic Profiling of A Homogenized Aggregate Sample From Asteroid (101955) Bennu

Evaluating the distribution and diversity of solvent-soluble organic molecules in extraterrestrial materials provide information about the physicochemical environments where prebiotic chemistry occurred and is essential for assessing the inventory of prebiotic compounds available to the early Earth. In this work, we conducted a comprehensive molecular characterization of solvent-soluble organic compounds in a homogenized aggregate sample (ID: OREX-800107-128) of unsorted regolith from asteroid (101955) Bennu returned by NASA’s OSIRIS-REx mission. Using two-dimensional gas chromatography coupled with high-resolution time-of-flight mass spectrometry (GC×GC-HRMS), we identified 87 organic compounds across several molecular classes, including alkanes, polycyclic aromatic hydrocarbons, and nitrogen-, oxygen-, and sulfur-bearing species. Comparison with the organic inventory of CI (Orgueil), C2-ungrouped (Tagish Lake and Tarda), and CM2 (Murchison) carbonaceous chondrites revealed that Bennu sample OREX-800107-128 is most similar to Tagish Lake and Tarda yet compositionally distinct from all of these meteorites. This Bennu sample exhibits a relatively high abundance of low-molecular-weight aromatics (e.g., toluene), pyridine derivatives, and sulfur species such as dimethyl sulfite, consistent with episodic low-temperature aqueous alteration. The presence of these organic compounds suggests that this material experienced chemically diverse processes in the parent body conducive to complex organic synthesis, including aldol condensation reactions responsible for N- and O-bearing compounds. We also compared the molecular distributions of this Bennu sample and previously analyzed samples from (162173) Ryugu to assess potential common origins between these two carbonaceous asteroids. Bennu shows more chemically diverse and nitrogen-rich organic materials than Ryugu. While both asteroids share broadly similar primitive compositions, the observed chemical differences indicate distinct evolutionary histories within a likely common formation environment though whether Bennu and Ryugu derive from a single compositionally heterogeneous parent body or from multiple closely related progenitors remains unresolved. Further detailed comparative analyses of material from Bennu, Ryugu, and specific carbonaceous meteorites (e.g., Tagish Lake and Tarda) will provide new insights into how the N-rich molecular profile observed in Bennu samples was formed and evolved in the outer Solar System.

sample return↗
NASA NTRS2026

A Review of Superconducting Electric Machines with On-Board Cryocoolers

This paper reviews the evolution and emerging direction of superconducting electric machines that employ onboard cryocoolers integrated directly into the rotor, eliminating the need for cryogenic fluid coupling and, in some cases, rotary seals. Traditional low-temperature superconducting (LTS) machines relied on external cryogenic systems and liquid helium transfer couplers, which introduced excessive complexity, poor reliability, and significant parasitic energy losses. The advent of high-temperature superconductors (HTS) has enabled compact, closed-cycle cryocoolers that support self-contained, fluid-free refrigeration architectures suitable for rotating applications. This paper examines the key technological challenges associated with on-board cryocooler integration and reviews three representative efforts by KAIST, NASA, and Hinetics, each illustrating distinct strategies and milestones toward practical implementation. KAIST demonstrated early proof-of-concept for rotating machines with on-board cryocoolers, NASA developed a shaft-integrated Stirling-type pulse tube cryocooler for a 1.4 MW hybrid-electric motor, and Hinetics achieved full-scale validation of a self-contained HTS rotor incorporating a commercial Stirling cryocooler and spoke-suspension torque tube. Collectively, these achievements confirm the technical feasibility of on-board cryogenic refrigeration and highlight steady progress toward compact and efficient superconducting rotating systems across various applications. Embedding cryocoolers directly within the rotor enables practical, efficient, and commercially viable superconducting propulsion technologies.

Cryogenics↗
NASA NTRS2026

List of Commercial and Advanced Developmental Niobium-Based Alloys of the Space Age

This report compiles a list of commercial and developmental niobium-based alloys developed during the Space Age (late 1950s through mid-1970s) for extreme-temperature applications, including rocket engine thrust chambers, hypersonic re-entry thermal protection systems, and space fission reactor loops. Niobium (Nb) was widely pursued because it provided the lowest density (~8.6 g/cc) among the primary refractory metals, a high melting temperature (~2470°C), exceptional low-temperature ductility, good formability, and compatibility with liquid alkali metals. An evaluation of physical metallurgy mechanisms, focusing on solid-solution strengthening via heavy refractory solutes (W, Mo, Ta), dual-purpose reactive solutes (Hf, Zr, Ti), and dispersion strengthening using carbides, nitrides, and oxides is presented. Additionally, the report compares Western and Soviet Union metallurgical approaches, explaining how supply chain factors and manufacturing infrastructure influenced element selection, interstitial chemistry, and alloy identification/naming conventions. Cataloging these historical alloy chemical compositions serves as a foundational reference for modern alloy additive manufacturing, thermodynamic CALPHAD modeling, and machine-learning discovery pipelines for next-generation extreme-environment niobium-based alloys.

Physical Metallurgy↗