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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 667 records · Page 37
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NASA NTRS1971

Subsystem radiation susceptibility analysis for deep-space missions

Scientific, unmanned spacecraft on mission to Jupiter and beyond will be subjected to nuclear radiation from the natural environment and onboard nuclear power sources which may be harmful to subsystems. This report postulates these environments and discusses practical considerations to ensure confidence that the spacecraft's materials and subsystems will withstand the effects of anticipated radiation. Degradation mechanisms are discussed.

West, W. S.↗
NASA NTRS1971

Analysis of selected deep space missions

Task 1 of the NEW MOONS (NASA Evaluation With Models of Optimized Nuclear Spacecraft) study is discussed. Included is an introduction to considerations of launch vehicles, spacecraft, spacecraft subsystems, and scientific objectives associated with precursory unmanned missions to Jupiter and thence out of the ecliptic plane, as well as other missions to Jupiter and other outer planets. Necessity for nuclear power systems is indicated. Trajectories are developed using patched conic and n-body computer techniques.

West, W. S.↗
NASA NTRS1972

The risk of solar proton events to space missions

The total dose in rads-tissue from solar protons was tabulated for weekly time intervals, and the number of weeks which gave a dose above 25 rads behind 10 g/sq cm of aluminum for the active 6 years of the 19th cycle were called dangerous or large event weeks. The number of such event weeks was found to be only 3 weeks for the past 20 years. Even though the chance for smaller events is examined, it was found that for any reasonable, high confidence level (95%), the smaller events could be ignored. Consequently, the total particle flux for the 19th cycle was divided by a factor of 3 and determined a single large event week. Using this spectrum, the tissue dose in rads is calculated at the center of an aluminum spherical shell.

Burrell, M. O.↗
NASA NTRS1972

A rotary actuator for space missions

A new rotary actuator is reported that consists of a motor functionally integrated with the transmission of a ring gear in a single element which is driven by the rotating magnetic vector in the stator. Because the number of teeth on the ring gear is different from that on the fixed ground gear, the ring gear rotates at a fraction of a revolution and simultaneously rotates the output gear in one eccentric cycle in the opposite direction. The advantages of the design are that only two bearings are required on a low speed output shaft.

Devine, E. J.↗
NASA NTRS1971

Biomedical findings on American astronauts participating in space missions.

Zero-gravity adaptive responses of man are discussed on the basis of biomedical data for 54 American astronauts, covering performance, locomotion, orientation, sleep and physiological and functional characteristics. Figures and diagrams are given for cardiovascular adaptation, weight loss, endocrine and electrolyte responses, fluid balance, skeletal responses, muscular and neuromuscular changes, exercise response tests and work capacity indicators. A review is given of current hypotheses concerning the processes involved in human adaptation to zero gravity. It is concluded that the immediate response of the body to weightlessness is a redistribution of the total circulating blood volume, leading to a loss of water, sodium and potassium through the kidneys and, thus, to a loss in total body weight.

Berry, C. A.↗
NASA NTRS1972

Development of four-dimensional atmospheric models and application techniques for space mission simulation.

The major objective of the four-dimensional atmospheric model program is to provide global profiles of moisture, temperature, pressure, and density from the surface to 25 km altitude. These models may then be used as input to the attenuation models for the purpose of simulating earth resource missions. Aspects of data processing are discussed together with homogeneous moisture regions, details regarding four-dimensional atmospheric models, and mission simulation procedures.-

Spiegler, D. B.↗
NASA NTRS1972

A survey of actuator shaft sealing techniques for extended space missions

Actuators for control and articulation aboard Mariner spacecraft have employed output shaft seals to maintain an internal gaseous atmosphere. On future missions, considerably greater expected lifetimes, temperature ranges, and radiation exposures have led to a need to determine the limitations of the present O-ring output shaft seal and to examine other candidate seals. Seals suited both to dynamic and static sealing were examined for potential use in three specific actuator applications and the following candidate seals were selected: (a) O-ring seal, (b) chevron seal, (c) bellows seal (linear actuator only), (d) magnetic fluid seal (rotary actuators only) and as a backup seal to any of the foregoing, (e) the labyrinth seal.

Hotz, G. M.↗
NASA NTRS1974

Application of nitrogen metabolism in autotrophic bacteria to chemosynthetic bioregeneration in space missions, supplement

The chemolithotroph, Hydrogenomonas eutropha, was considered as a life support, bioregenerative system. This project focuses on several metabolic functions that are related to the proposed nitrogen cycle between man and this microbe. Specifically this organism has the capability to utilize as the sole nitrogen source such urine components as urea and fifteen individual amino acids, but not nine other amino acids. The effectiveness of utilization was high for many amino acids. Several specific growth inhibitions were also observed. The enzyme that catalyzes the incorporation of ammonia in the medium into amino acids was identified as a NADP-specific, L-glutamate dehydrogenase. This enzyme has a constitutive nature. This organism can synthesize all of its amino acids from carbon dioxide and ammonia. Therefore with the background literature of multiple pathways of individual amino acid biosyntheses, our evidence to date is consistent with the Hydrogeneomonas group having the same pathway of valine-isoleucine formation as the classical E. coli.

Wixom, R. L.↗
NASA NTRS1973

Direct oxidation of strong waste waters, simulating combined wastes in extended-mission space cabins

The applications of modern technology to the resolution of the problem of solid wastes in space cabin environments was studied with emphasis on the exploration of operating conditions that would permit lowering of process temperatures in wet oxidation of combined human wastes. It was found that the ultimate degree of degradation is not enhanced by use of a catalyst. However, the rate of oxidation is increased, and the temperature of oxidation is reduced to 400 F.

Ross, L. W.↗