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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 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Analysis of large-scale Martian topography variations. I - Data preparation from earth-based radar, earth-based CO2 spectroscopy, and Mariners 6 and 7 CO2 spectroscopy.

Using direct radar ranging of surface heights on Mars and spectrophotometric observations of absorptions produced by carbon dioxide molecules in the Martian atmosphere, data have been obtained on Martian topographical variations at spatial resolutions ranging from about 100 to 1000 km. These data have been studied and analyzed. As a result, a surface height contour map has been produced which clearly reveals a structural complex of blocks and basins whose distribution enhances the magnitude of low-degree surface harmonics. It is emphasized that Mars possesses unexpectedly pronounced topography which can have important geophysical consequences.

Wells, R. A.↗
NASA NTRS1974

TERSSE: Definition of the Total Earth Resources System for the Shuttle Era. Volume 3: Mission and System Requirements for the Total Earth Resources System

Resource management missions to be performed by TERSSE are described. Mission and user requirements are defined along with information flows developed for each major resource management mission. Other topics discussed include: remote sensing platforms, remote sensor requirements, ground system architecture, and such related issues as cloud cover, resolution, orbit mechanics, and aircraft versus satellite.

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NASA NTRS1974

TERSSE: Definition of the Total Earth Resources System for the Shuttle Era. Volume 6: An Early Shuttle Pallet Concept for the Earth Resources Program

A space shuttle sortie mission which can be performed inexpensively in the early shuttle era and which, if the necessary intermediate steps are accomplished provides a major technological advance for the user organization-the U.S. Bureau of Census is described. The orbital configuration created for the Urban Land Use/1980 Census mission is illustrated including sensors and ground support equipment along with the information flow for the mission. Factors discussed include: specific Census Bureau functions to be supported by the mission; hardware and flight operations necessary for implementation of the mission; and integration of the TERSSE pallet into a shuttle mission.

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NASA NTRS1977

Scintillation statistics measured in an earth-space-earth retroreflector link

Scintillation was measured in a vertical path from a ground-based laser transmitter to the Geos 3 satellite and back to a ground-based receiver telescope and, the experimental results were compared with analytical results presented in a companion paper (Bufton, 1977). The normalized variance, the probability density function and the power spectral density of scintillation were all measured. Moments of the satellite scintillation data in terms of normalized variance were lower than expected. The power spectrum analysis suggests that there were scintillation components at frequencies higher than the 250 Hz bandwidth available in the experiment.

Bufton, J. L.↗
NASA NTRS1980

Initial assessment of the effects of energetic ion injections in the magnetosphere due to the transport of satellite power system components from low earth orbit to geosynchronous earth orbit

Potentially serious environmental effects exist when cargo orbital transfer vehicle (COTV) ion propulsion is used on the scale proposed in the preliminary definition studies of the Satellite Power System. These effects of the large scale injections of ion propulsion exhaust in the plasmasphere and in the outer magnetosphere were shown to be highly model dependent with major differences existing in the predicted effects of two models, the ion cloud model and the ion sheath model. The expected total number density deposition of the propellant Ar(+) in the plasmasphere, the energy spectra of the deposited Ar(+) and time dependent behavior of the Ar(+) injected into the plasmasphere by a fleet of COTV vehicles differ drastically between the two models. The ion sheath model was demonstrated to be applicable to the proposed Ar(+) beam physics if the beam was divergent and turbulent whereas the ion cloud model was not a realistic approximation for such a beam because the "frozen-field" assumption on which it is based is not valid.

Curtis, S. A.↗
NASA NTRS1984

Global excitation of wave phenomena in a dissipative multiconstituent medium. I - Transfer function of the earth's thermosphere. II - Impulsive perturbations in the earth's thermosphere

A transfer function approach is taken in constructing a spectral model of the acoustic-gravity wave response in a multiconstituent thermosphere. The model is then applied to describing the thermospheric response to various sources around the globe. Zonal spherical harmonics serve to model the horizontal variations in propagating waves which, when integrated with respect to height, generate a transfer function for a vertical source distribution in the thermosphere. Four wave components are characterized as resonance phenomena and are associated with magnetic activity and ionospheric disturbances. The waves are either trapped or propagate, the latter becoming significant when possessing frequencies above 3 cycles/day. The energy input is distributed by thermospheric winds. The disturbances decay slowly, mainly due to heat conduction and diffusion. Gravity waves appear abruptly and are connected to a sudden switching on or off of a source. Turn off of a source coincides with a reversal of the local atmospheric circulation.

Mayr, H. G.↗
NASA NTRS1987

Nimbus 7 earth radiation budget wide field of view climate data set improvement. I - The earth albedo from deconvolution of shortwave measurements

A deconvolution method for extracting the top of the atmosphere (TOA) mean, daily albedo field from a set of wide-FOV (WFOV) shortwave radiometer measurements is proposed. The method is based on constructing a synthetic measurement for each satellite observation. The albedo field is represented as a truncated series of spherical harmonic functions, and these linear equations are presented. Simulation studies were conducted to determine the sensitivity of the method. It is observed that a maximum of about 289 pieces of data can be extracted from a set of Nimbus 7 WFOV satellite measurements. The albedos derived using the deconvolution method are compared with albedos derived using the WFOV archival method; the developed albedo field achieved a 20 percent reduction in the global rms regional reflected flux density errors. The deconvolution method is applied to estimate the mean, daily average TOA albedo field for January 1983. A strong and extensive albedo maximum (0.42), which corresponds to the El Nino/Southern Oscillation event of 1982-1983, is detected over the south central Pacific Ocean.

Hucek, Richard R.↗
NASA NTRS1988

Partitioning of rare earth elements between hibonite and melt and implications for nebular condensation of the rare earth elements

The effect of oxygen fugacity on the partitioning of REEs between hibonite and silicate melt is investigated in hibonite-growth experiments at 1470 C. The experimental procedures and apparatus are described, and the results are presented in extensive tables and graphs and characterized in detail. The absolute activity coefficients in hibonite are estimated as 330 for La, 1200 for Eu(3+), and 24,000 for Yb. It is inferred that ideal solution behavior cannot be assumed when calculating REE condensation temperatures for (Ca, Al)-rich inclusions in carbonaceous chondrites.

Drake, Michael J.↗
NASA NTRS1990

Climate and atmospheric modeling studies. Climate applications of Earth and planetary observations. Chemistry of Earth and environment

The research conducted during the past year in the climate and atmospheric modeling programs concentrated on the development of appropriate atmospheric and upper ocean models, and preliminary applications of these models. Principal models are a one-dimensional radiative-convective model, a three-dimensional global climate model, and an upper ocean model. Principal applications have been the study of the impact of CO2, aerosols and the solar 'constant' on climate. Progress was made in the 3-D model development towards physically realistic treatment of these processes. In particular, a map of soil classifications on 1 degree x 1 degree resolution has been digitized, and soil properties have been assigned to each soil type. Using this information about soil properties, a method was developed to simulate the hydraulic behavior of soils of the world. This improved treatment of soil hydrology, together with the seasonally varying vegetation cover, will provide a more realistic study of the role of the terrestrial biota in climate change. A new version of the climate model was created which follows the isotopes of water and sources of water (or colored water) throughout the planet. Each isotope or colored water source is a fraction of the climate model's water. It participates in condensation and surface evaporation at different fractionation rates and is transported by the dynamics. A major benefit of this project has been to improve the programming techniques and physical simulation of the water vapor budget of the climate model.

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