Measurements of the earth's radiation budget from satellites during a five-year period. I - Extended time and space means
Earth radiation budget measurements, noting planetary albedo, IR radiant emittance and net balance
Suomi, V. E.↗
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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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Multispectral sensing of moisture stress
Laboratory reflectance data, and field tests with multispectral remote sensors provide support for this hypotheses that differences in moisture content and water deficits are closely related to foliar reflectance from woody plants. When these relationships are taken into account, automatic recognition techniques become more powerful than when they are ignored. Evidence is increasing that moisture relationships inside plant foliage are much more closely related to foliar reflectance characteristics than are external variables such as soil moisture, wind, and air temperature. Short term changes in water deficits seem to have little influence on foliar reflectance, however. This is in distinct contrast to significant short-term changes in foliar emittance from the same plants with changing wind, air temperature, incident radiation, or water deficit conditions.
Olson, C. E., Jr.↗
Venting of fission products and shielding in thermionic nuclear reactor systems
Most thermionic reactors are designed to allow the fission gases to escape out of the emitter. A scheme to allow the fission gases to escape is proposed. Because of the low activity of the fission products, this method should pose no radiation hazards.
Salmi, E. W.↗
Optical properties of thermal control coating contaminated by MMH/N2O4 5-pound thruster in a vacuum environment with solar simulation
Cat-a-lac Black, and S13G thermal control coatings were exposed to the exhaust of a thruster in a simulated space environment. Vacuum was maintained at less than 10 to the minus 5th power torr during thruster firing in the liquid helium cooled facility. The thruster was fired in a 50-millisecond pulse mode and the accumulated firing time was 224 seconds. Solar absorptance (alpha sub s) and thermal emittance (sigma) of the coatings were measured in-situ at intervals of 300 pulses. A calorimetric technique was used to measure alpha sub s and sigma. The tests, technique, and test results are presented. The Cat-a-lac Black coatings showed no change in alpha sub s or sigma. The S13G showed up to 25 percent increase in alpha sub s but no change in sigma.
Sommers, R. D.↗
Development of a carbon cloth heat post module for thermal vacuum testing of a spinning spacecraft
Development of a high temperature, high power density, isothermal, rapid transient, infrared thermal module is described. The investigation of various alternative approaches is discussed, as well as the rationale leading to the choice of a carbon cloth concept. Evolution of module design configurations and a summary of the development test results are included, along with a detailed description of the final design, which incorporated a black plate emitter radiantly heated by the carbon cloth. The final module configuration met design criteria during a 200-hour thermal vacuum performance test at 1000 F operating temperature without contaminating a solar cell array.
Levine, M. B.↗
Apollo 9 thermal-control-coating degradation
Analytical studies, ground-test data, and flight data before 1967 indicated that degradation of Apollo thermal-control coatings could be expected, possibly to an extent requiring spacecraft design changes to accomplish the worst-case lunar-landing mission. On the Apollo 9 mission, specimens of Apollo thermal-control coatings were retrieved by the astronauts during the extravehicular activity. These specimens were the first to be returned to earth from space unaffected by entry conditions. Subsequent measurements of the thermophysical properties (solar absorptance and hemispherical emittance) of the thermal-control-sample coatings revealed degradation levels well within the design capability of the Apollo spacecraft.
Smith, J. A.↗
Investigation of phase-change coatings for variable thermal control of spacecraft
An investigation was conducted to determine the feasibility of producing a spacecraft coating system that could vary the ratio of its solar absorptance to thermal emittance to adjust automatically for changes in the thermal balance of a spacecraft. This study resulted in a new concept called the phase-change effect which uses the change that occurs in the optical properties of many materials during the phase transition from a crystalline solid to an amorphous material. A series of two-component model coatings was developed which, when placed on a highly reflecting substrate, exhibited a sharp decrease in solar absorptance within a narrow temperature range. A variable thermal control coating can have a significant amount of temperature regulation with the phase-change effect. Data are presented on several crystallite-polymer formulations, their physical and optical properties, and associated phase-change temperatures. Aspects pertaining to their use in a space environment and an example of the degree of thermal regulation attainable with these coatings is also given.
Kelliher, W. C.↗
The NASA earth resources spectral information system: A data compilation
The NASA Earth Resources Spectral Information System and the information contained therein are described. It contains an ordered, indexed compilation of natural targets in the optical region from 0.3 to 45.0 microns. The data compilation includes approximately 100 rock and mineral, 2600 vegetation, 1000 soil, and 60 water spectral reflectance, transmittance, and emittance curves. Most of the data have been categorized by subject, and the curves in those subject areas have been plotted on a single graph. Those categories with too few curves and miscellaneous categories have been plotted as single-curve graphs. Each graph, composite of single, is fully titled to indicate curve source and is indexed by subject to facilitate user retrieval.
Leeman, V.↗
The diminiode: A research and development tool for nuclear thermionics
Diminiodes are fixed-or variable-gap cesium diodes with plane miniature emitters and guarded collectors. In addition to smallness, their relative advantages are simplicity, precision, ease of fabrication, interchangeability of parts, cleanliness, full instrumentation, ruggedness, and economy. With diminiodes and computers used in thermionic performance mapping, a thorough electrode screening program becomes practical.
Morris, J. F.↗
Studies of thermionic materials for space power applications
Service life tests of LC-8 and LC-9 carbide-fueled thermionic converters are discussed. Post operational tests of the converters to show emitter diametric change, microstructures of cladding and fuel, and analysis of fuel composition are described. The fabrication and performance of high temperature thermocouples used in the test procedures are included.
Source record↗
Improvement of reusable surface insulation material
The results are presented of a program to improve the reusable surface insulation (RSI) system through the improvement of the LI-1500 material properties and the simplification of the RSI system. The improvements made include: 2500 F-capability RSI systems, water-impervious surface coatings, establishment of a high-emittance coating constituent, development of a secondary water-reduction system, and achievement of a lower density (9 pcf) RSI material.
Source record↗
The Nasa earth resources spectral information system: A data compilation, first supplement
The NASA Earth Resources Spectral Information System and the information contained therein are described. It is intended to be used as a supplement to the NASA Earth Resources Spectral Information System: A Data Compilation, N72-28366. This supplement includes approximately 500 rock and mineral, 100 soil, and 30 vegetation bidirectional and directional reflectance, transmittance, emittance, and degree-of-polarization curves in the optical region from 0.2 to 22.0 microns. The data have been categorized by subject and each curve plotted on a single graph. For some rocks and minerals, all curves of the same type, differing only in particle size, have been plotted on one grid as a composite plot. Each graph, composite or single, is fully titled to indicate curve source and is indexed by subject to facilitate user retrieval.
Leeman, V.↗
Status of reusable surface insulation thermal protection system technology programs
The development of three low-density rigidized insulation materials for the shuttle TPS application is reported. These materials consist of one high purity silica system and two systems based on mullite, an aluminum silicate. Both systems consist of fibers joined together with appropriate binders to obtain a rigidized insulation composite. Both material systems require the application of a glassy coating to provide a wear resistant, high emittance surface and to prevent the absorption of water by the fiber matrix. The technology program has addressed the development of water impervious coatings, methods of assembling the materials in design concepts while minimizing the thermal stress in the insulation, achieving compatibility between the RSI material and the structural system, and test evaluations to demonstrate the feasibility of the surface insulation concept.
Greenshields, D. H.↗
Cesium-diode performances from the 1963-to-1971 Thermionic Conversion Specialist Conferences
Indexes and summaries of the conference papers containing cesium-diode results are presented. Lists of converter materials, geometries, conditions, outputs, and lifetimes accompany the references. Simple chemical designations for emitters, collectors, and additives direct the reader to appropriate selections.
Morris, J. F.↗
Infrared radiation of thin plastic films.
A combined analytical and experimental study is presented for infrared radiation characteristics of thin plastic films with and without a metal substrate. On the basis of the thin-film analysis, a simple analytical technique is developed for determining band-averaged optical constants of thin plastic films from spectral normal transmittance data for two different film thicknesses. Specifically, the band-averaged optical constants of polyethylene terephthalate and polyimide were obtained from transmittance measurements of films with thicknesses in the range of 0.25 to 3 mil. The spectral normal reflectance and total normal emittance of the film side of singly aluminized films are calculated by use of optical constants; the results compare favorably with measured values.
Tien, C. L.↗
Low-energy solar positrons.
Fluxes of solar particles, consistent with Kinsey's (1970) measurements and demodulated in a manner consistent with the cosmic-ray transport equations discussed by Gleeson and Axford (1967), are shown to be able to produce low-energy positrons in the solar atmosphere via unstable CNO beta-particle emitters. Computed positron fluxes are presented for various diffusion coefficient values and compared with measurements of Cline and Hones (1970).
Gregory, C. T.↗
Results of a comprehensive program for analysis of thermal radiative properties.
An extensive program has been developed to identify, collect, extract, analyze, and disseminate thermal radiative property data on materials of use to the aerospace endeavors under conditions likely to exist in their application. The properties examined include thermal emittance, reflectance, absorptance, and transmittance. Reference is made to the coverage of the results which is organized in three major volumes, representing the most comprehensive treatment on this subject matter.
Dewitt, D. P.↗
Apollo 12 thermal radiation properties.
The spectral and total thermal radiation properties are presented as a function of bulk density for lunar fines from the Apollo 12 mission collected on the Ocean of Storms. The total emittance is presented as a function of temperature from 90 to 400 K and the solar reflectance (albedo) for near normal incidence.
Birkebak, R. C.↗