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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Evidence of a major fault zone along the California-Nevada state line 35 deg 30 min to 36 deg 30 min north latitude

The author has identified the following significant results. Geologic reconnaissance guided by analysis of ERTS-1 and Apollo-9 satellite imagery and intermediate scale photography from X-15 and U-2 aircraft has confirmed the presence of a major fault zone along the California-Nevada state line, between 35 deg 30 min and 36 deg 30 min north latitude. The name Pahrump Fault Zone has been suggested for this feature after the valley in which it is best exposed. Field reconnaissance has indicated the existence of previously unreported faults cutting bedrock along range fronts, and displacing Tertiary and Quaternary basin sediments. Gravity data support the interpretation of regional structural discontinuity along this zone. Individual fault traces within the Pahrump Fault Zone form generally left-stepping en echelon patterns. These fault patterns, the apparent offset of a Laramide age thrust fault, and possible drag folding along a major fault break suggest a component of right lateral displacement. The trend and postulated movement of the Pahrump Fault Zone are similar to the adjacent Las Vegas Shear Zone and Death Valley-Furnace Creek Faults, which are parts of a regional strike slip system in the southern Basin-Range Province.

Liggett, M. A.↗
NASA NTRS1972

Mascons - Progress toward a unique solution for mass distribution.

Through a series of analyses with high-altitude Lunar Orbiter and low-altitude Apollo 15 Doppler gravity data, it is shown that the Serenity mascon is a thin body whose horizontal dimensions are well determined and show a strong correlation with circular wrinkle ridge structure. Analysis to date has not uniquely determined the depth of the anomalous mass. However, geological evidence strongly suggests that the mass excess is near the surface, because (1) the surface solution has a geometry highly suggestive of the partial filling of a ringed circular basin, and (2) the boundaries of the anomalous mass separate regions of shallow and deep mare flooding.

Phillips, R. J.↗
NASA NTRS1973

The nature of circular maria based on gravity studies.

Current thinking on the evolution of major lunar morphological features, i.e., large lunar circular basins, and on the nature and origin of surface structures observed in the fill deposits is summarized. The great lunar circular basins must result from high-velocity impact of large bodies with the moon. A hydrostatic mechanism is outlined, and a working hypothesis is presented for the evolution of lunar circular basins subsequent to their origin by impact. In the main appeal is made to Doppler gravity data to support the hypothesis, although photographic and altimetric information is also used. It is considered that all large ringed circular basins follow a common evolutionary path of superisostatic volcanic flooding followed by partial and variable isostatic adjustment. The difference between basins is the amount of flooding, which in turn may be related to the center of figure-center of mass offset of the moon.

Phillips, R. J.↗
NASA NTRS1973

Mars - Crustal structure inferred from Bouguer gravity anomalies.

Bouguer gravity has been computed for the equatorial region of Mars by differencing free air gravity and the gravity predicted from topographic variations. The free air gravity was generated from an eighth-order set of spherical harmonic coefficients. The gravity from topographic variations was generated by integrating a two-dimensional Green's function over each contour level. The Bouguer gravity indicates crustal inhomogeneities on Mars that are postulated to be variations in crustal thickness. The Tharsis ridge is a region of thick continental type crust. The gravity data, structural patterns, topography, and surface geology of this region lead to the interpretation of the Tharsis topographic high as a broad crustal upwarp possibly associated with local formation of lower-density crustal material and subsequent rise of a thicker crust. The Amazonis region is one of several basins of relatively thin crust, analogous to terrestrial ocean basins. The Libya and Hellas basins, which are probable impact features, are also underlain by thin crust and are possible regions of mantle upwelling.

Phillips, R. J.↗
NASA NTRS1975

The International Heat Pipe Experiment

On October 4, 1974 the International Heat Pipe Experiment was launched aboard a Black Brant Sounding Rocket from White Sands, New Mexico. The flight provided six minutes of near zero gravity during which a total of ten separate heat pipe experiments were performed. The fifteen heat pipes which were tested represent some of the latest American and European technology. This flight provided the first reported zero gravity data on cryogenic and flat plate vapor chamber heat pipes. Additionally, valuable design and engineering data was obtained on several other heat pipe configurations. This paper will discuss the payload and four of the individual experiments.

Mcintosh, R.↗
NASA NTRS1975

The isostatic state of Martian topography

As is evidenced by the gravity data, the regional topography of Mars falls into two disctinct age groups. The older group is isostatically compensated at relatively shallow depth. All of our analyses indicate that the younger group is only partly compensated and that the depth of partial compensation is also shallow. The young topography is composed primarily of the Tharsis plateau and the adjacent low areas of Chryse and Amazonis. They appear to have all undergone the same amount of partial compensation, suggesting a comtemporaneous origin. All of the topography is consistent with a model of viscous relaxation in an environment of approximate thermal steady state. The minimum viscosity necessary to explain the partial compensation is 10 to the 27th power P, a value typical of a number of lunar studies. Alternatively, the strength required to support the uncompensated fraction of the topography is similar to strengths determined for the earth and moon.

Phillips, R. J.↗
NASA NTRS1976

Thermodynamics of a solar mixture of molecular hydrogen and helium at high pressure

The thermodynamic properties of a model molecular hydrogen and helium mixture are calculated in the strongly interacting region of 0.005 to 0.3 per cu cm for a range of temperatures that are of interest for the envelopes of the Jovian planets. Computed adiabats fit the gravity data and boundary conditions from model atmospheres of Jupiter.

Slattery, W. L.↗
NASA NTRS1976

The International Heat Pipe Experiment

On October 4, 1974, the International Heat Pipe Experiment was launched aboard a Black Brant sounding rocket from White Sands, New Mexico. The flight provided six min of near zero gravity during which a total of ten separate heat pipe experiments was performed. The fifteen heat pipes tested represent some of the latest American and European technology. This flight provided the first reported zero gravity data on cryogenic and flat plate vapor chamber heat pipes. Additionally, valuable design and engineering data were obtained on several other heat pipe configurations. The payload and several of its experiments are discussed.

Mcintosh, R.↗
NASA NTRS1977

Convection pattern and stress system under the African plate

Studies on tectonic forces from satellite-derived gravity data have revealed a subcrustal stress system which provides a unifying mechanism for uplift, depression, rifting, plate motion and ore formation in Africa. The subcrustal stresses are due to mantle convection. Seismicity, volcanicity and kimberlite magmatism in Africa and the development of the African tectonic and magnetic features are explained in terms of this single stress system. The tensional stress fields in the crust exerted by the upwelling mantle flows are shown to be regions of structural kinship characterized by major concentration of mineral deposits. It is probable that the space techniques are capable of detecting and determining the tectonic forces in the crust of Africa.

Liu, H.-S.↗
NASA NTRS1977

Pioneer 10 and 11 radio occultations by Jupiter

Results on the temperature structure of the Jovian atmosphere are reviewed which were obtained by applying an integral inversion technique combined with a model for the planet's shape based on gravity data to Pioneer 10 and 11 radio-occultation data. The technique applied to obtain temperature profiles from the Pioneer data consisted of defining a center of refraction based on a computation of the radius of curvature in the plane of refraction and the normal direction to the equipotential surface at the closest approach point of a ray. Observations performed during the Pioneer 10 entry and exit and the Pioneer 11 exit are analyzed, sources of uncertainty are identified, and representative pressure-temperature profiles are presented which clearly show a temperature inversion between 10 and 100 mb. Effects of zonal winds on the reliability of radio-occultation temperature profiles are briefly discussed.

Kliore, A. J.↗
NASA NTRS1978

Mantle convection pattern and subcrustal stress field under Asia

Satellite tracking and surface gravity data are used to model the subcrustal stress fields in the terrestrial mantle beneath Asia; the results permit interpretation of the tectonic and seismic systems in China. The east and west China blocks, together with five seismic zones, are identified and related to metallogenic domains on the Chinese mainland. In addition, it is shown that the subcrustal stresses beneath China are arranged perpendicularly to the major fault systems and seismic belts. Stress calculations indicate a notable zone of compression in north China, associated with the Shansi Graben, the Linfen Basin Systems and, possibly, the high seismicity of the region.

Liu, H.-S.↗
NASA NTRS1979

A revised 5 minute gravimetric geoid and associated errors for the North Atlantic calibration area

A revised 5 minute gravimetric geoid and its errors were computed for the North Atlantic calibration area using GEM-8 potential coefficients and the latest gravity data available from the Defense Mapping Agency. This effort was prompted by a number of inconsistencies and small errors found in previous calculations of this geoid. The computational method and constants used are given in detail to serve as a reference for future work.

Mader, G. L.↗
NASA NTRS1979

An isostatic model for the Tharsis province, Mars

A crust-upper mantle configuration is proposed for the Tharsis province of Mars which is isostatic and satisfies the observed gravity data. The model is that of a low density upper mantle compensating loads at both the surface and crust-mantle boundary. Solutions are found for lithospheric thickness greater than about 300 km, for which the stress differences are less than 750 bars. This model for Tharsis is similar to the compensation mechanism under the Basin and Range province of the western United States. These provinces also compare favorably in the sense that they are both elevated regions of extensional tectonics and extensive volcanism.

Sleep, N. H.↗
NASA NTRS1979

Gravity anomaly and structure associated with the Lamont region of the moon

Lamont is a unique lunar feature in southwestern Mare Tranquillitatis associated with radial and concentric ridge patterns and a positive free-air gravity anomaly. Best fitting models to high and low altitude gravity data place nearly all of the anomalous mass in the subsurface, consistent with the hypothesis that Lamont is a mascon. Lamont is positioned on the axis of a 1500 m deep north-south topographic trough occupying western Mare Tranquillitatis. It is proposed that this trough is a synclinal fold in the lunar crust and the tectonic fabric of western Tranquillitatis is consistent with the superposition of the stress fields due to synclinal folding and the loading of the lithosphere by the Lamont mascon.

Dvorak, J.↗
NASA NTRS1981

Ellipsoidal corrections for geoid undulation computations

The computation of accurate geoid undulations is usually done combining potential coefficient information and terrestrial gravity data in a cap surrounding the computation point. In doing this a spherical approximation is made that can cause the errors that were investigated. The equations dealing with ellipsoidal corrections developed by Lelgemann and by Moritz were used to develop a computational procedure considering the ellipsoid as a reference surface. Terms in the resulting expression for the geoid undulation are identified as ellipsoidal correction terms. These equations were developed for the case where the Stokes function is used, and for the case where the modified Stokes function is used. For a cap of 20 deg the correction can reach -33 cm.

Rapp, R. H.↗
NASA NTRS1980

Mantle convection pattern and subcrustal stress field under South America

The tectonic, igneous and metallogenic features of South America are discussed in terms of the crustal deformation associated with stresses due to mantle convection as inferred from the high degree harmonics in the geopotential field. The application of Runcorn's model for the laminar viscous flows in the upper mantle to satellite and gravity data results in a convection pattern which reveals the ascending flows between the descending Nazca plate and the overlying South American plate as well as segments of the descending Nazca plate beneath South America. The arc volcanism in South America is shown apparently to be related to the upwelling of high-temperature material induced by the subduction of the Nazca plate, with the South American basin systems associated with downwelling mantle flows. The resulting tensional stress fields are shown to be regions of structural kinship characterized by major concentrations of ore deposits and related to the cordillera, shield and igneous systems and the upward Andean movements. It is suggested that the upwelling convection flows in the upper mantle, coupled with crustal tension, have provided an uplift mechanism which has forced the hydrothermal systems in the basement rocks to the surface.

Liu, H.-S.↗