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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

Ecology and thermal inactivation of microbes in and on interplanetary space vehicle components

Data showing that 90 C was a more effective temperature than 125 C for the destruction of Bacillus subtilis var. niger when the head-space moisture was fixed at 474 micrograms H2O/ml have been confirmed and are summarized. The influence of head-space moisture at 90 C was investigated and it was observed that as the head-space moisture was increased 474 micrograms H2O/ml, there was a corresponding increase in lethality of the system. This moisture level corresponded to 100% relative humidity at 90 C, and additional water in the cans should have had no effect. A profound descrease was observed in the destruction of the organisms when additional water was added. The discontinuity observed in these data is troublesome and must be resolved as the first step in an orderly exploration of low temperature inactivation of B. subtilis var. niger.

Campbell, J. E.↗
NASA NTRS1971

Energy changes of cosmic rays in interplanetary space.

The observation reported by Murray et al. (1971), in which a feature or ?kink' in the kinetic-energy spectrum of solar cosmic rays from a solar burst was seen to decrease with time, is examined. By means of calculations based on a model for cosmic ray bursts, it is demonstrated that the observed rate cannot be interpreted immediately as the rate of loss of energy, and factors are indicated which must be considered in the interpretation of the data.

Gleeson, L. J.↗
NASA NTRS1972

Lyman-alpha measurements of neutral hydrogen in the outer geocorona and in interplanetary space.

Results of hydrogen Lyman-alpha (1216 A) measurements made on a continuous basis by a two-channel photometer on Ogo 5 from March 1968 to June 1971. The highly elliptical orbit provided measurements of both the outer geocorona and of the 1216-A sky background emission, since geocoronal scattering is minimal at the apogee distance of 150,000 km. Selected data (through 1970) are presented, as well as an interpretation of the three principal discoveries to date - namely, (1) a pronounced antisolar enhancement of the geocoronal scattering beyond 70,000 km, which is regarded as evidence for a hydrogen 'geotail' produced by solar Lyman-alpha radiation pressure; (2) a clear correlation of periodic variations in the sky background emission with solar activity associated with solar rotation; and (3) an annual variation of the 1216-A sky background emission, caused by the earth's orbital motion within the cavity created by the solar wind in the nearby interstellar hydrogen.

Thomas, G. E.↗
NASA NTRS1972

Cosmic-ray diffusion coefficient in interplanetary space.

The authors of three recent papers reporting cosmic-ray electron differential intensities near the earth during 1966 and 1968 in the rigidity range above 500 MV have concluded that the observations are not compatible with a diffusion coefficient that can be written as a product of a rigidity-dependent part and a part that is a function of heliocentric distance. It is shown in this paper that, with an interstellar electron spectrum and a near-earth spectrum given, a diffusion coefficient of the above form can always be determinedand the conclusion noted above cannot be sustained. Diffusion coefficients appropriate to the observations are given.

Gleeson, L. J.↗
NASA NTRS1972

Observation of Lyman-alpha emission in interplanetary space

The extraterrestrial Lyman-alpha emission was mapped by the OGO 5 satellite, when it was outside the geocorona. Three maps, obtained at different periods of the year, are presented and analyzed. The results suggest that at least half of the emission takes place in the solar system, and give strong support to the theory that in its motion toward the apex, the sun crosses neutral atomic hydrogen of interstellar origin, giving rise to an apparent interstellar wind.

Bertaux, J. L.↗
NASA NTRS1972

Interstellar helium in interplanetary space

The velocity distribution function of He(+) in the solar wind at 1 AU is calculated with the assumption that the source is photoionization of a cold (T = 100 K), neutral interstellar wind. If the spiral magnetic field is noise free, the velocity distribution is diffuse and would not produce a peak at 4(E over Q) sub H in an E over Q particle spectrum. If the velocity of the interstellar wind with respect to the sun lies in the ecliptic, a large variation of the He(+) number density with respect to ecliptic longitude is expected.

Feldman, W. C.↗