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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 NTRS1978

Process for utilizing low-cost graphite substrates for polycrystalline solar cells

Low cost polycrystalline silicon solar cells supported on substrates were prepared by depositing successive layers of polycrystalline silicon containing appropriate dopants over supporting substrates of a member selected from the group consisting of metallurgical grade polycrystalline silicon, graphite and steel coated with a diffusion barrier of silica, borosilicate, phosphosilicate, or mixtures thereof such that p-n junction devices were formed which effectively convert solar energy to electrical energy. To improve the conversion efficiency of the polycrystalline silicon solar cells, the crystallite size in the silicon was substantially increased by melting and solidifying a base layer of polycrystalline silicon before depositing the layers which form the p-n junction.

Chu, T. L.↗
NASA NTRS1998

High Performance Materials Applications to Moon/Mars Missions and Bases

Two classes of material processing scenarios will feature prominently in future interplanetary exploration: in situ production using locally available materials in lunar or planetary landings and high performance structural materials which carve out a set of properties for uniquely hostile space environments. To be competitive, high performance materials must typically offer orders of magnitude improvements in thermal conductivity or insulation, deliver high strength-to-weight ratios, or provide superior durability (low corrosion and/or ablative character, e.g., in heat shields). The space-related environmental parameters of high radiation flux, low weight, and superior reliability limits many typical aerospace materials to a short list comprising high performance alloys, nanocomposites and thin-layer metal laminates (Al-Cu, Al-Ag) with typical dimensions less than the Frank-Reed-type dislocation source. Extremely light weight carbon-carbon composites and carbon aerogels will be presented as novel examples which define broadened material parameters, particularly owing to their extreme thermal insulation (R-32-64) and low densities (<0.01 g/cu cm) approaching that of air itself. Even with these low-weight payload additions, rocket thrust limits and transport costs will always place a premium on assembling as much structural and life support resources upon interplanetary, lunar, or asteroid arrival. As an example, for in situ lunar glass manufacture, solar furnaces reaching 1700 C for pure silica glass manufacture in situ are compared with sol-gel technology and acid-leached ultrapure (<0.1% FeO) silica aerogel precursors.

Noever, David A.↗
NASA NTRS1998

High Performance Materials Applications to Moon/Mars Missions and Bases

Two classes of material processing scenarios will feature prominently in future interplanetary exploration- in situ production using locally available materials in lunar or planetary landings and high performance structural materials which carve out a set of properties for uniquely hostile space environments. To be competitive, high performance materials must typically offer orders of magnitude improvements in thermal conductivity or insulation, deliver high strength-to-weight ratios, or provide superior durability (low corrosion and/or ablative character, e.g. in heat shields). The space-related environmental parameters of high radiation flux, low weight and superior reliability limits many typical aerospace materials to a short list comprising high performance alloys, nanocomposites and thin-layer metal laminates (Al-Cu, Al-Ag) with typical dimensions less than the Frank-Reed-type dislocation source. Extremely light weight carbon-carbon composites and car on aerogels will be presented as novel examples which define broadened material parameters, particularly owing to their extreme thermal insulation (R-32-64) and low densities (less than 0.01 g/cc) approaching that of air itself. Even with these low weight payload additions, rocket thrust limits and transport costs will always place a premium on assembling as much structural and life support resources upon interplanetary, lunar or asteroid arrival. As an example for in situ lunar glass manufacture, solar furnaces reaching 1700 C for pure silica glass manufacture in situ are compared with sol-gel technology and acid-leached ultrapure (less than 0.1% FeO) silica aerogel precursors.

Noever, David A.↗
NASA NTRS1984

A comparison of aerobraking and aerocapture vehicles for interplanetary missions

Several design features for employing aerobraking and aerocapture techniques on interplanetary spacecraft are described. Recent studies have identified silica fabrics mounted on carbon composite ribs as suitable aerobraking spacecraft shield materials. Aerocapture is best achieved with a biconic aeroshell design, with the aeroshell supported by Al honeycomb panels and allowing primitive aerodynamic maneuverability. The aeroshell would be covered with thermal protection materials capable of elevated temperatures of magnitudes that are a function of the expected atmospheric density, the surface area, the entry speed, spacecraft mass and maneuverability. Both technologies are concluded ready for implementation and development costs are estimated for various missions, showing that aerocapture will provide for greater payload masses, except for a Jupiter mission.

Hoffman, S.↗
NASA NTRS1999

Development of a Pressure-Fed Rocket Engine Using Hydrogen Peroxide and JP-8

A pressure-fed rocket engine using hydrogen peroxide and JP-8 was designed and demonstrated for upper stage space transportation applications. The engine utilizes silver plated screen catalyst to decompose 85% hydrogen peroxide (by weight). The decomposed high-temperature gas causes the JP-8 to auto-ignite and undergo chemical reaction. An ablative chamber using silica phenolic was used as the combustion chamber. The present effort includes catalyst development, injector evaluation, and chamber char and erosion characterization. Wagonwheel-type distribution and support plates were used in the catalyst bed design to reduce pressure drop, to increase active area, and to avoid flow channeling. Various fuel injection and mixing approaches were investigated and the combustion efficiency was in the range from 89 to 98%, depending on injector design and operating conditions. Fuel film cooling, up to 40% of the total fuel flow, was found to be ineffective with the current engine configuration. A ring injector was selected because of the satisfactory performance and its low cost. The char and erosion rates were determined through hot-fire tests. The char depth was found to be a function of axial distance, which was related to the progress of chemical reaction. Correlation of the char and erosion rates was developed as a design database for future applications,

Wu, P.-K.↗
NASA NTRS2008

A Stainless-Steel Mandrel for Slumping Glass X-Ray Mirrors

We have fabricated a precision full -cylinder stainless-steel mandrel at Marshall Space Flight Center. The mandrel is figured for a 30-cm-diameter primary (paraboloid) mirror of an 840-cm focal-lengthWolter-1 telescope. We have developed this mandrel for experiments in slumping.thermal forming at about 600 C-of glass mirror segments at Goddard Space Flight Center, in support of NASA fs participation in the International X -ray Observatory (IXO). Precision turning of stainless ]steel mandrels may offer a lowcost alternative to conventional figuring of fused -silica or other glassy forming mandrels. We report on the fabrication, metrology, and performance of this first mandrel; then we discuss plans and goals for stainless-steel mandrel technology.

ODell, Stephen L.↗
NASA NTRS2023

New Mie Scattering Diffuse Targets Development and Characterization

Earth science remote sensing observations require the detection and measurement of light originating from bright targets, such as clouds, and darker targets, such as an open ocean. This requirement drives the need to design, develop, and characterize improved calibration targets in support of current and future NASA instruments. New diffuse targets to be used as spectral albedo calibration standards were developed and characterized. The new targets based on fused silica or/and pressed and sintered Polytetrafluoroethylene (PTFE) were developed to be Earth scene specific. The various reflectance levels are achieved by modifying the material parameters, thickness, and surface finish. The new targets were characterized in laboratory and simulated space environments. We acquired high accuracy reflectance and transmittance data using a precision optical scatterometer and spectrophotometer located in the NASA Goddard Space Flight Center (GSFC) Diffuser Calibration Lab. The Total hemispherical reflectance (THR) and Bidirectional Reflectance Distribution Function (BRDF) were measured over the range of solar incident and scattered elevation and azimuthal angles typically realized on orbit by remote sensing instruments. We intend to space certify the new calibration targets after concluding on-orbit testing on the International Space Stations (ISS) scheduled for the second half of 2023.

Georgi Georgiev↗
NASA NTRS1996

Lightweight, Thermally Insulating Structural Panels

Lightweight, thermally insulating panels that also serve as structural members developed. Honeycomb-core panel filled with low-thermal-conductivity, opacified silica aerogel preventing convection and minimizes internal radiation. Copper coating on face sheets reduces radiation. Overall thermal conductivities of panels smaller than state-of-art commercial non-structurally-supporting foam and fibrous insulations. On Earth, panels suitable for use in low-air-pressure environments in which lightweight, compact, structurally supporting insulation needed; for example, aboard high-altitude aircraft or in partially evacuated panels in refrigerators.

Eisen, Howard J.↗
NASA NTRS2012

Quasi-Monolithic Structures for Spaceflight Using Hydroxide-Catalysis Bonding

Future space-based missions will take measurements of the universe with unprecedented results. To do this, these missions will require materials and bonding techniques with ever-increasing stability in order to make their measurements. As an example, the Laser Interferometer Space Antenna (LISA) will detect and observe gravitational waves in the 0.1 mHz to 1 Hz frequency range with strain sensitivities on the order of 10(exp -21) at its most sensitive frequency. To make these measurements, critical components such as the optical bench or telescope support structure, will need to have path-length stabilities of better than 1 pm/(square root)Hz. The baseline construction method for the LISA optical bench is to affix fused silica optical components to a Zerodur baseplate using hydroxide-catalysis bonding (HCB). HCB is a recently developed technique that allows the bonding of glasses, some metals, and silicon carbide with significant strength and stability with a bond thickness of less than a few micrometers. In addition, a wide range of surface profiles can be bonded using only a small amount of hydroxide solution. These characteristics make HCB ideal for adhering optical components in complex optical systems. In addition to being used to construct the LISA optical bench, the HCB technique shows great promise for constructing other structures such as hollow retroreflectors to be used for lunar laser ranging, or a visible nulling coronograph to be used for exo-planet detection. Here we present construction techniques that could be used to make an optical bench, hollow retroreflector, nulling coronograph, or other quasi-monolithic structures using HCB. In addition, we present dimensional stability results of an optical bench that was made using HCB, as well as HCB strength measurements.

Preston, Alix↗
NASA NTRS1982

Gravity deflections of lightweighted mirrors

Two 20-in-diameter lightweight fused-silica mirrors, one having a single arch configuration and the other a double arch configuration, were tested interferometrically at their centers of curvature in both a face-up and face-down support mode. By subtracting the wavefront errors in these two support modes, the gravity deflections were determined in spite of some residual figure error. It is found that the single arch mirror, supported horizontally on three points, has about half the total deflection of the double arch design. The single arch mirror is twice as stiff azimuthally as the double arch, but radially the double arch has four times the stiffness of the single arch. If a more uniform azimuthal support were provided for the double arch, its deflections would be expected to improve significantly.

Anderson, D.↗
NASA NTRS2009

A Stainless-Steel Mandrel for Slumping Glass X-ray Mirrors

We have fabricated a precision full-cylinder stainless-steel mandrel at Marshall Space Flight Center. The mandrel is figured for a 30-cm diameter primary (paraboloid) mirror of an 840-cm focal-length Wolter-1 telescope. We have developed this mandrel for experiments in slumping.thermal forming at about 600 C.of glass mirror segments at Goddard Space Flight Center, in support of NASA's participation in the International X-ray Observatory (IXO). Precision turning of stainless-steel mandrels may offer a low-cost alternative to conventional figuring of fused-silica or other glassy forming mandrels. We report on the fabrication, metrology, and performance of this first mandrel; then we discuss plans and goals for stainless-steel mandrel technology.

Gubarev, Mikhail V.↗
NASA NTRS2024

SCIFLI HORIS Windowpane Optical Analysis

This NASA Technical Memorandum summarizes windowpane optical analyses for the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification and Security Regolith Explorer) mission [1] supported by the SCIFLI (Scientifically Calibrated In-Flight Imagery) team [2] at NASA Langley Research Center (NASA LaRC). The SCIFLI team led a NASA multi-center team in characterization of fused silica (FS) and anti-reflective coated (AR-coated) sapphire materials for use as aircraft windowpanes. These materials were needed for the Hypervelocity OSIRIS-REx Reentry Imaging & Spectroscopy (HORIS) mission and were tested to generate performance parameters relevant to the flight environment. Some of the assessed parameters included optical quality, transmittance, reflectance, color balance, birefringence, transmitted wavefront error, wedge, and haziness of the windows. In order to evaluate the material characteristics in a uniform manner, several criteria were held constant. For example, the physical dimensions of the test articles were held constant (i.e., 17-inch diameter aircraft windowpane and 2-inch diameter witness samples). In this way, the comparison of test results from one material specimen to another was invariant with regard to the manner in which the tests were conducted. This also reduced the variability in how the data were reported. As a result, the results shown in this report, including test data generated by NASA can be used for windowpane material evaluation and future material design trades. Window designers can use the data and the testing method along with the testing matrices to efficiently match material performance to their design and mission objectives and requirements. Standardized testing methodologies and data reduction procedures are described in this report. Unless otherwise noted in the data itself, all the windowpane materials were tested in order to characterize their performance for the HORIS mission. One appendix has been included in this report. These include detailed wavefront interferograms of transmitted wavefront error and optical wedge used in the generation of aggregated material performance.

SCIFLI↗
NASA NTRS1997

Optical and Atomic Force Microscopy Characterization of PbI2 Quantum Dots

Lead iodide (PbI2) clusters were synthesized from the chemical reaction of NaI (or KI) with Pb(NO3)2 in H2O, D2O, CH3OH, and C3H7OH media. The observation of the absorption features above 350 nm with the help of integrating sphere accessory strongly suggests the quantum dot formation of PbI2 in solution. Spectral comparison between the synthesized PbI2 clusters in solution and PbI2 nanophase by impregnation of PbI2 in four different pore-sized porous silica indicates that the PbI2 cluster size in solution is less than 2.5 nm in lateral dimension. Atomic force microscopy (AFM) measurements show that the PbL clusters deposited onto three different molecularly flat surfaces are single-layered. The measured height is 1.0 - 0.1 nm. The swollen layer thickness can be attributed to the intralayer contraction from the strong lateral interaction among PbI2 molecules, which is supported by ab initio calculation. Raman scattering measurement of LO and TO modes of PbI2 in bulk and in the confined state were also conducted in 50-150 cu cm region. The observed three bands at 74, %, 106 1/cm are assigned to TO2, LO2, and LO, mode, respectively. The relatively small red-shift in LO modes may be caused by the surface phonon polaritons of PbI2 nanophase in the porous silica.

Mu, R.↗
NASA NTRS1979

Optical system of the visual imaging subsystem on the Viking Orbiter spacecraft

The development of the optical system for the Viking Orbiter spacecraft is presented. Each spacecraft consisted of an orbiter and a lander, and the orbiter provided support during the lander descent, landing and operation on the Martian surface, and prior to separation the orbiter provided science data for site selection and certification. To support these objectives each orbiter carried twin camera systems with identical 475 mm f/3.5 telescopes. The development of the Visual Imaging Subsystem which used all spherical catadioptric cassegrains with all elements fabricated from pure fused silica and Mangin primary mirrors is described. Computer aided design optimization and the ray aberration analysis of the final design are presented. The Viking telescopes had high theoretical and measured performance and obtained many high quality images of the Martian surface.

Larks, L.↗
NASA NTRS2005

Computational Aerothermodynamic Assessment of Space Shuttle Orbiter Tile Damage: Open Cavities

Computational aerothermodynamic simulations of Orbiter windside tile damage in flight were performed in support of the Space Shuttle Return-to-Flight effort. The simulations were performed for both hypervelocity flight and low-enthalpy wind tunnel conditions and contributed to the Return-to-Flight program by providing information to support a variety of damage scenario analyses. Computations at flight conditions were performed at or very near the peak heating trajectory point for multiple damage scenarios involving damage windside acreage reaction cured glass (RCG) coated silica tile(s). The cavities formed by the missing tile examined in this study were relatively short leading to flow features which indicated open cavity behavior. Results of the computations indicated elevated heating bump factor levels predicted for flight over the predictions for wind tunnel conditions. The peak heating bump factors, defined as the local heating to a reference value upstream of the cavity, on the cavity floor for flight simulation were 67% larger than the peak wind tunnel simulation value. On the downstream face of the cavity the flight simulation values were 60% larger than the wind tunnel simulation values. On the outer mold line (OML) downstream of the cavity, the flight values are about 20% larger than the wind tunnel simulation values. The higher heating bump factors observed in the flight simulations were due to the larger driving potential in terms of energy entering the cavity for the flight simulations. This is evidenced by the larger rate of increase in the total enthalpy through the boundary layer prior to the cavity for the flight simulation.

Pulsonetti, Maria↗
NASA NTRS2000

Microscopic physical biomarkers in carbonate hot springs: implications in the search for life on Mars

Physical evidence of life (physical biomarkers) from the deposits of carbonate hot springs were documented at the scale of microorganisms--submillimeter to submicrometer. The four moderate-temperature (57 to 72 degrees C), neutral pH springs reported on in this study, support diverse communities of bacteria adapted to specific physical and chemical conditions. Some of the microbes coexist with travertine deposits in endolithic communities. In other cases, the microbes are rapidly coated and destroyed by precipitates but leave distinctive mineral fabrics. Some microbes adapted to carbonate hot springs produce an extracellular polymeric substance which forms a three-dimensional matrix with living cells and cell remains, known as a biofilm. Silicon and iron oxides often coat the biofilm, leading to long-term preservation. Submicrometer mineralized spheres composed of calcium fluoride or silica are common in carbonate hot spring deposits. Sphere formation is biologically mediated, but the spheres themselves are apparently not fossils or microbes. Additionally, some microbes selectively weather mineral surfaces in distinctive patterns. Hot spring deposits have been cited as prime locations for exobiological exploration of Mars. The presence of preserved microscopic physical biomarkers at all four sites supports a strategy of searching for evidence of life in hot spring deposits on Mars.

NASA Center JSC↗
NASA NTRS1997

Effects of Compression, Staging, and Braid Angle on Braided Rope Seal Performance

Future turbine engines and industrial systems will be operating at increased temperatures to achieve more demanding efficiency and performance goals. In the highest temperature sections of the engine new material systems such as ceramics and intermetallics are being considered to withstand the harsh thermal environment. Components constructed of these low expansion-rate materials experience thermal strains and a resulting reduction of life when rigidly attached to high expansion-rate, superalloy support structures. Seals are being designed to both seal and to serve as compliant mounts allowing for relative thermal growths between high temperature but brittle primary structures and the surrounding support structures. Previous seal research yielded several braided rope seal designs which demonstrated the ability to both seal and serve as a compliant mount. The hybrid seal was constructed of an all-ceramic (alumina-silica) core overbraided with a superalloy wire sheath (cobalt based superalloy). The all ceramic seal was constructed of an all-ceramic (alumina-silica) core overbraided with multiple ceramic (alumina-silica) sheath layers. Program goals for braided rope seals are to improve flow resistance and/or seal resilience. To that end, the current report studies the test results of: baseline and modified hybrid seals; two stage hybrid and two stage all-ceramic seal configurations; and single stage hybrid and single stage all-ceramic seal configurations for a range of seal crush conditions. Hybrid seal modifications include increasing the sheath braid angle and core coverage. For the same percent seal cross-sectional crush, results show that increasing the hybrid seal braid angle increased seal stiffness and seal unit load, resulting in flows approximately one third of the baseline hybrid seal flows. For both hybrid and all-ceramic seals, two stage seal configurations significantly outperformed single stage configurations. Two stage seal flows were at least 30% less than the single stage seal flows for the same seal crush. Furthermore, test results of single stage seals indicate that for both all-ceramic and hybrid seals, a specific seal crush condition exists at which minimum flows are achieved (i.e. increasing seal crush beyond a certain point does not result in better flow performance). Flow results are presented for a range of pressures and temperatures from ambient to 1300 F, before and after scrubbing. Compression tests results show that for both all-ceramic and hybrid seals, seal preload and stiffness increase with seal crush, but residual seal interference remains constant.

Steinetz, Bruce M.↗
NASA NTRS1973

Field studies in support of Nimbus-E surface composition mapping radiometer

If the outputs of the two channels are spacially registered and combined to generate a third variable which reflects the differences between the two outputs, then this variable can then be redisplayed in image form and its magnitude should be relatable to the silica content of the rocks imaged. Two methods were proposed for generating this third variable, the first is to take the difference in apparent temperature between the two channels and the second is to ratio the voltage outputs of the two channels. The responses of the two channel high resolution surface composition mapping radiometer and the thermal channels of the MSDS scanner were calculated from data recorded with the NASA IR pallet and simulate the output of these systems had they been flying over the same targets as the IR pallet.

Lyon, R. J. P.↗