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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 433 records · Page 24
All sourcesNASA NTRSDOE OSTI
NASA NTRS1964

Discussion of the General Electric proposal to develop a computer program to select thermal coatings for passive temperature control of satellites

The General Electric Company, Missiles and Space Division, submitted/a proposal to NASA for the development of an IBM 7094 computer program which would select the exterior surface coatings for passively controlling spacecraft temperatures. G. E. claims that the "trial and error" procedures currently used can be accomplished more rationally and can therefore be programmed for a digital computer. In the ASME paper, 63-HT-41, which was presented at the ASME-AIChE Heat Transfer Conference at Boston in August, 1963, Costello, Harper, and Cline, described the procedures that have been used at G. E. to develop a coating selection program subject to the following restrictions: 1. Steady-state conditions prevail, 2. Heat transfer occurs by radiation only, 3. Temperatures are optimized at only one interior point in the spacecraft, an d 4. Only the solar absorptance of the external coatings is varied to optimize temperature. The emittance must remain constant at initially specified values. General Electric proposes to develop a generalized program in three steps: 1. The program would vary both solar absorptance and hemispherical emittance to obtain the optimum coating patterns; 2. Temperatures would be optimized at more than one interior point; and 3. The equations would be modified to account for both conduction and radiation heat transfer. In the development of the general program, the scope would be restricted to steady-state heat transfer. Since the thermal designs of most spacecraft are based primarily on nearly equilibrium conditions, the proposed program could have wide application. An obvious extension of the proposed program would be to account for transient temperatures.

IBM 7090 COMPUTER↗
NASA NTRS1997

Arctic and Antarctic Sea Ice Concentrations from Multichannel Passive-Microwave Satellite Data Sets: October 1978-September 1995 User's Guide

Satellite multichannel passive-microwave sensors have provided global radiance measurements with which to map, monitor, and study the Arctic and Antarctic polar sea ice covers. The data span over 18 years (as of April 1997), starting with the launch of the Scanning Multichannel Microwave Radiometer (SMMR) on NASA's SeaSat A and Nimbus 7 in 1978 and continuing with the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave/Imager (SSMI) series beginning in 1987. It is anticipated that the DMSP SSMI series will continue into the 21st century. The SSMI series will be augmented by new, improved sensors to be flown on Japanese and U.S. space platforms. This User's Guide provides a description of a new sea ice concentration data set generated from observations made by three of these multichannel sensors. The data set includes gridded daily ice concentrations (every-other-day for the SMMR data) for both the north and south polar regions from October 26, 1978 through September 30, 1995, with the one exception of a 6-week data gap from December 3, 1987 through January 12, 1988. The data have been placed on two CD-ROMs that include a ReadMeCD file giving the technical details on the file format, file headers, north and south polar grids, ancillary data sets, and directory structure of the CD-ROM. The CD-ROMS will be distributed by the National Snow and Ice Data Center in Boulder, CO.

Sea ice concentration↗
NASA NTRS2003

Control of Interacting Vortex Flows at Subsonic and Transonic Speeds Using Passive Porosity

A wind tunnel experiment was conducted in the NASA Langley Research Center (LaRC) 8-foot Transonic Pressure Tunnel (TPT) to determine the effects of passive surface porosity on vortex flow interactions about a general research fighter configuration at subsonic and transonic speeds. Flow- through porosity was applied to a wind leading-edge extension (LEX) mounted to a 65 deg cropped delta wind model to promote large nose-down pitching moment increments at high angles of attack. Porosity decreased the vorticity shed from the LEX, which weakened the LEX vortex and altered the global interactions of the LEX and wing vortices at high angles of attack. Six-component forces and moments and wing upper surface static pressure distributions were obtained at free- stream Mach numbers of 0.50, 0.85, and 1.20, Reynolds number of 2.5(10(exp-6) per foot, angles of attack up to 30 deg and angles of sideslip to plus or minus 8 deg. The off-surface flow field was visualized in selected cross-planes using a laser vapor screen flow visualization technique. Test data were obtained with a centerline vertical tail and with alternate twin, wing-mounted vertical fins having 0 deg and 30 deg cant angles. In addition, the porosity of the LEX was compartmentalized to determine the sensitivity of the vortex- dominated aerodynamics to the location and level of porosity applied to the LEX.

NATO FURNISHED↗
NASA NTRS2001

Passive imaging based hazard avoidance for spacecraft safe landing

In this paper, a new and fast passive sensing based hazard avoidance approach for spacecraft safe landing is suggested. This approach contains two important algorithms: a texture based landing site selection algorithm and a landing site slope estimation algorithm.

spacecraft safe landing passive imaging homography↗