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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 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

The global distribution of stratospheric ozone from OGO-4 BUV observations

Latitude-height cross sections of the mass mixing ration are shown for two different years for equinoctial and Northern Hemisphere winter periods. The data represent two week averages for October 1967 and 1968, and for January 1958 and 1969. For October 1967, the ozone distribution is symmetrical about the equator although the values are higher in the Southern Hemisphere (spring) and about 30-35 km. In October 1968, the distribution about the equator is quite symmetrical. The latitudinal variation at levels above about 3 mb (40 km) is small where photochemical processes are dominant in determining the ozone distribution. In 1967, there is a slight increase at these levels towards the poles that reflect a temperature influence in the ozone chemistry in the upper stratosphere. This increase, however, is absent in 1968.

Clayson, M. H.↗
NASA NTRS1972

Satellite measurements of high latitude convection electric fields.

This paper reviews the first results of satellite experiments to measure magnetospheric convection electric fields using the double-probe technique. The earliest successful measurements were made with the low-altitude (680-2530 km) polar orbiting Injun-5 spacecraft. The Injun-5 results are compared with the initial findings of the electric field experiment on the polar orbiting OGO-6 satellite. Electric field measurements from the OGO-6 satellite have substantiated many of the initial Injun-5 observations with improved accuracy and sensitivity. The OGO-6 detector revealed the persistent occurrence of anti-sunward convection across the polar cap region at velocities not generally detectable with the Injun-5 experiment. The OGO-6 observations also provided information indicating that the location of the electric field reversal shifts equatorward during periods of increased magnetic activity. The implications of the electric field measurements for magnetospheric and auroral structure are summarized, and a list of specific recommendations for improving future experiments is presented.

Cauffman, D. P.↗
NASA NTRS1972

Acoustic response comparison for a spacecraft tested with and without a shroud

For the purpose of evaluating the simulation problems encountered in an acoustic environment laboratory, a research test program using the launch phase simulator was initiated. The Orbiting Geophysical Observatory (OGO) structural model and the Nimbus-type shroud were used as test items. Compared are the acoustic vibratory response of the OGO model when enclosed within a shroud with the OGO acoustical response with the shroud removed, while subjected to an equivalent acoustic environment. The results indicate that a shroud is necessary in order to perform a realistic acoustic test.

Bruck, L. R.↗
NASA NTRS1972

A model of the Starfish flux in the inner radiation zone

A model of the Starfish electrons injected into the radiation belt in July 1962 was determined for epoch September 1964. This model distinguishes between artificial and natural electrons and provides the artificial unidirectional electron flux as a function of equatorial pitch angle, energy, and L value. The model is based primarily upon data from the OGO-1, OGO-3, OGO-5, 1963-38C, and the OV3-3 satellites. Decay times for the Starfish electrons are given as a function of energy and L value. These decay times represent the best compromise between a number of independently determined values. The times at which the artificial Starfish flux component had become insignificant in comparison to the natural flux component are determined as functions of energy and L value. These times are determined by two separate methods, and averaged values are presented. It is shown that Starfish electrons, by the present time, have become insignificant for all energies and L values.

Teague, M. J.↗
NASA NTRS1973

Parametric description of thermospheric ion composition results.

Results of an attempt to accumulate an ion composition data base for an international reference ionosphere (IRI) with the aid of polar-orbiting satellites. A progress report is presented on the preparation of the results from the Bennett RF ion spectrometer experiment on Ogo 4 and 6 using the most extensive set of thermospheric ion composition data yet available. An example of the pole-to-pole distributions of all ions detected by the spectrometer on Ogo 6 is given which shows considerable structure resulting from both altitude and latitude variations. Also, an example is given of the type of analysis made possible by the combined scope of the Ogo ion composition data base and the IRI statistical sorting routine.

Taylor, H. A., Jr.↗
NASA NTRS1976

Comparisons of measured and theoretical thermospheric daily composition variations

A comparison of the diurnal component of the daily variation in the neutral composition data from the San Marco 3 Nace (Neutral Atmospheric Composition Experiment) mass spectrometer at 220, 250, and 280 km, the OGO-6 model data at 450 km, rocket measurements of nitrogen between 140 and 300 km, and the two-constituent theoretical model of Mayr and Volland (1973) gives good agreement for molecular nitrogen and atomic oxygen. The Nace and rocket measurements overlap in altitude, and there is good agreement in the amplitude and phase of the diurnal and semidiurnal components for molecular nitrogen. The helium diurnal amplitude and phase of the theoretical model are in fair agreement with the Nace results, while the amplitude from the OGO-6 model at 450 km is much larger than the model predicts, a result suggesting that the OGO-6 model diurnal amplitude may be overestimated as the result of an incomplete separation of local-time and seasonal effects.

Kasprzak, W. T.↗
NASA NTRS1979

Does ELF chorus show evidence of power line stimulation

A study to determine the effect of power line radiation on the stimulation of the ELF chorus detected on OGO-5 is presented. Chorus shows a maxima over the Eastern USSR, Greenland, and Central Siberia and minima over central and Eastern Canada, a distribution different than the OGO-3. This discrepancy is explained as due to data oversampling in the previous study; the OGO-5 data were reanalyzed with the oversampling removed, showing that none of the longitudinal maxima or minima are statistically significant. It is concluded that there is no significant correlation between longitude and chorus occurrence which implies that there is little or no evidence of power line harmonic radiation effects on chorus triggering.

Tsurutani, B. T.↗
NASA NTRS1968

Ion cutoff whistlers.

Ion cut-off whistlers observed during VLF experiment aboard OGO 2 and OGO 4, noting possible application to relative ionospheric proton concentration determination

Muzzio, J. L. R.↗
NASA NTRS1968

Orbiting Geophysical Observatory Attitude Control Subsystem Design Survey. NASA/ERC Design Criteria Program, Guidance and Control

This design survey summarizes the history of the Orbiting Geophysical Observatories' (OGO) Attitude Control Subsystem (ACS) from the proposal phase through current flight experience. Problems encountered in design, fabrication, test, and on orbit are discussed. It is hoped that the experiences of the OGO program related here will aid future designers.

Mc Kenna, K. J.↗
NASA NTRS1971

Ionospheric nf sub H resonances: Frequency shifts versus plasma conditions

The Alouette 2 resonances observed near the harmonics of the electron cyclotron frequency f sub H reveal frequency shifts (relative to the n(f sub H) values derived from model field calculations) which can be interpreted in terms of plasma wave dispersion effects. These effects are observed on the 2(f sub H) resonance when it is near the resonance observed close to the upper hybrid frequency f sub T. The observations suggest that an oblique echo model may be required to give a proper interpretation of the 2(f sub H) resonance. Cyclotron damping can be ignored only when the angle between the propagation vector and the direction perpendicular to the earth's magnetic field B is less than a few degrees for the 2(f sub H) wave, and less than a few tenths of a degree for the n(f sub H) waves with n 2. The negative offset of the absolute value of B inferred from the plasma resonance observations is consistent with expectations based on recent OGO 3 and OGO 5 rubidium magnetometer observations at higher altitudes in the equatorial regions.

Benson, R. F.↗
NASA NTRS1972

Ultraviolet observations of comets

The first observations of a comet in the vacuum ultraviolet were obtained on January 14, 1970, when OAO-2 recorded the spectrum of the bright comet Tago-Sato-Kosaka (1969g). The observations revealed, among other things, the predicted extensive hydrogen Lyman alpha halo. OAO-2 continued to collect spectrophotometric measurements of this comet throughout January of that year; a photograph of the nucleus in Lyman alpha revealed finer scale structures. In February of 1970, the bright comet Bennet (1969i) became favorable for space observations. On the basis of the OAO discovery, OGO-V made several measurements of comet Bennet with low spatial resolution photometers. Comet Enke was detected by OGO in January of 1971 at a large heliocentric distance from its Lyman alpha emission.

Code, A. D.↗
NASA NTRS1972

Charged particle and magnetic field research in space

Research completed and in progress is described, related publications and reports are listed, and abstracts of papers and talks on results of the research are given. The charged particle research centered on OGO-5 and OGO-6 electron spectrometer data, and theoretical radiation belt studies. Work on the ATS-1 magnetometer project included development of production data reduction programs, development of spectral analysis procedures, and scientific studies of ULF waves at synchronous orbit. The magnetic fields research also included work on the Mariner project and theoretical studies on the solar wind.

Source record↗
NASA NTRS1972

A new view of the ring current

Observations of the quiet time ring current intensity and distribution in the magnetosphere by OGO-3 and OGO-5 are given. The differences in quiet time ring currents and ring currents observed during magnetic storms are discussed.

Sugiura, M.↗