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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1969

High vacuum adhesion test apparatus.

Vacuum apparatus for measuring uniaxially loaded metal surfaces interfacial adhesion, showing surface oxide removal effectiveness influence in adhesion strength

Hordon, M. J.↗
NASA NTRS1972

Research on bearing lubricants for use in a high vacuum

Work, during the research program, was concentrated on lubricant development, gear lubrication and evaluation, providing coated test specimens, advising NASA contractors about solid lubrication specific applications, and investigation of new method of attaching lubricating solids to bearing surfaces by sputtering technique.

Campbell, M. E.↗
NASA NTRS1970

Ultra high vacuum adhesion testing of NERVA engine materials

The primary objective of this research program was to determine the effects of surface cleaning and deliberate gaseous contamination on the adhesion behavior of selected candidate materials for use in the NERVA nuclear rocket engine program. Using a torsion balance technique, the relationship between the normal compressive load applied to crossed rod samples and the resultant contact resistance was used to ascertain the extent of adhesion under each set of experimental conditions. In addition to an evaluation of the static adhesion behavior of selected materials combinations, the experimental apparatus was modified to permit a similar investigation relating to the effects of specific tangential displacements of the sample wires, i.e., their sliding friction behavior. During the course of this subcontract, the materials combinations 440 C vs. 440 C. pyrographite vs ZTA graphite, Nbc (graphite) vs. Nbc (graphite), and Electrolize Inconel 718 vs. Au electroplated 302 S/S were evaluated.

Source record↗
NASA NTRS1973

Operation of small rocket engines in the JPL high-vacuum molecular space simulator (Molsink)

The feasibility of operating small rocket engines in the Molsink facility was demonstrated. A 0.44-N (0.1-lbf) hydrazine engine and a 0.18-N (0.04-lbf) thruster using cold gas from a hydrazine plenum system were operated for both flight duty cycles and off-nominal conditions. The exhaust gases from these thrusters contain NH3, N2, and H2. The chamber was also calibrated for larger bipropellant engines using nitrogen tetroxide/monomethyl hydrazine (NTO/MMH). The exhaust products of these engines contain CO2, CO, H2, H2O, and H2. A mixture of cold gases simulating the engine exhaust was injected through a nozzle under conditions simulating thrust levels up to 26.7-N (6 lbf). Pulsing and continuous operations were investigated. The chamber background pressure traces were compared with the traces obtained for the same thrusters operated with pure nitrogen at approximately equivalent thrust. Satisfactory recuperation times were encountered in all the pulsing modes. Test times greater than 20s were obtained in steady state operation before the vacuum chamber back pressure climbed to prohibitive values.

Chirivella, J. E.↗
NASA NTRS1977

Small monopropellant thruster contamination measurement in a high-vacuum low-temperature facility

The contamination that results from the exhaust plume of small thrusters used for attitude control maneuvers can pose severe problems for long-life satellite systems. In order to assess this type of contamination problem, analytical and experimental techniques must be developed. Mass deposition rate measurements of a representative 0.44-N thrust hydrazine thruster were made in a space simulation chamber using five appropriately placed variable-temperature quartz crystal microbalances. The mass deposition rates within the thruster plume were measured while operating the thruster over a wide range of operating parameters, including duty cycles, catalyst bed start temperatures, propellant water variation, as well as thruster aging effects. The contamination measurements were made over a temperature range of 144 to 256 K for all duty cycles. In addition, the nominal duty cycle of 100 msec on and 10 sec off was run at a temperature of 106 K. These data will make possible better prediction of deposition rates of contaminants from thrusters used in satellite systems.

Passamaneck, R. S.↗