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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 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

Press conference on Skylab

A discussion on the Skylab reentry date and its predicted effects is presented. The plans for a coordination center and its activities to monitor the reentry of Skylab are discussed.

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NASA NTRS1980

Development of a high strength hot isostatically pressed /HIP/ disk alloy, MERL 76

A nickel-based powder metal disk alloy developed for use in advanced commercial gas turbines is described. Consideration is given to final alloy chemistry modifications made to achieve a desirable balance between tensile strength and stress rupture life and ductility. The effects of post-consolidation heat treatment are discussed, the preliminary mechanical properties obtained from full-scale turbine disks are presented.

Evans, D. J.↗
NASA NTRS1980

Voyager Saturn encounter press briefing

The briefing reviewed the mission planning of the Voyager project. The near encounter trajectories of both Voyager spacecraft were examined. The Saturn system is discussed with particular emphasis on Saturn's moons.

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NASA NTRS1981

Development of energy-absorbing reaction-sintered Si3N4 surface layers on hot-pressed Si3N4

Energy-absorbing Si3N4 surface layers on dense Si3N4 substrates were formed by in-place nitridation of fine-grained silicon powder. Ballistic impact tests performed on samples with 1-mm thick layers at room temperature and 1370 C showed up to an eightfold increase in the energy necessary to fracture the substrate. For maximum impact resistance, a small amount (about 20 vol %) of residual Si must be present in the reaction-sintered Si3N4 surface layer. Thermal cycling to 1370 C did not affect impact resistance, even though a considerable amount of SiO2 formed within the reaction-sintered Si3N4 layer during cycling. Erosion testing of samples in a Mach 0.8 burner rig at 1370 C resulted in minimal surface recession of the surface layer. Chemically vapor-deposited SiC-coated material similarly tested exhibited no surface recession.

Brennan, J. J.↗
NASA NTRS1983

Press Kit: Project RCA (Satcom 1R)

To replace the RCA SATCOM 1 satellite which provided Earth communications for seven years, NASA is to launch RCA SATCOM 1R using a Delta 3924 launch vehicle. The satellite is to be placed at 139 degrees W longitude, 35,900 kilometers (23,000) miles above the equator. On the seventh apogee, the kick motor will be fired to produce a near synchronous orbit. Satellite life, with continuous full power, is designed to be 10 years. Features of the satellite and launch operations are described.

Source record↗
NASA NTRS1983

Thermal conductance of pressed contacts at liquid helium temperatures

The thermal contact conductance of a 0.4 micrometer surface finish OFHC copper sample pair has been investigated from 1.6 to 3.8 K for a range of applied contact forces up to 670 N. Experimental data have been fitted to the relation Q = the integral alpha T to the nth power dt by assuming that the thermal contact conductance is a simple power function of the sample temperature. It has been found that the conductance is proportional to T squared and that conductance increases with an increase in applied contact force. These results confirm earlier work.

Salerno, L. J.↗
NASA NTRS1983

Thermal conductance measurements of pressed OFHC copper contacts at liquid helium temperatures

The thermal conductance of oxygen-free high conductivity (OFHC) copper sample pairs with surface finishes ranging from 0.1 to 1.6-micrometers rms roughness was investigated over the range of 1.6 to 6.0-K under applied contact forces up to 670 N. The thermal conductance increases with increasing contact force; however, no correlation can be drawn with respect to surface finish.

Salerno, L. J.↗
NASA NTRS1985

Pressed boride cathodes

Results of experimental studies of emission cathodes made from lanthanum, yttrium, and gadolinium hexaborides are presented. Maximum thermal emission was obtained from lanthanum hexaboride electrodes. The hexaboride cathodes operated stably under conditions of large current density power draw, at high voltages and poor vacuum. A microtron electron gun with a lanthanum hexaboride cathode is described.

Wolski, W.↗
NASA NTRS1985

Thermal conductance measurements of pressed OFHC copper contacts at liquid helium temperatures

The thermal conductance of oxygen-free high conductivity (COFHC) copper sample pairs with surface finishes ranging from 0.1 to 1.6-micrometers rms roughness was investigated over the range of 1.6 to 6.0-K under applied contact forces up to 670 N. The thermal conductance increases with increasing contact force; however, no correlation can be drawn with respect to surface finish.

Salerno, L. J.↗