Astrogeology Science Center

Publications

Filter Total Items: 858
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Year Published: 1994

Galileo Photometry of Asteroid 951 Gaspra

Galileo images of Gaspra make it possible for the first time to determine a main-belt asteroid's photometric properties accurately by providing surface-resolved coverage over a wide range of incidence and emission angles and by extending the phase angle coverage to phases not observable from Earth. We combine Earth-based telescopic photometry over...

Helfenstein, P.; Veverka, J.; Thomas, P.C.; Simonelli, D.P.; Lee, P.; Klaasen, K.; Johnson, T. V.; Breneman, H.; Head, J.W.; Murchie, S.; Fanale, F.; Robinson, M.; Clark, B.; Granahan, J.; Garbeil, H.; McEwen, A.S.; Kirk, Randolph L.; Davies, M.; Neukum, G.; Mottola, S.; Wagner, R.; Belton, M.; Chapman, C.; Pilcher, C.

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Year Published: 1994

The Geology of Gaspra

The surface of Gaspra can be divided into several facets separated by ridges. Superimposed on the facets and ridges are two populations of craters. Type 1 craters are crisply defined and constitute a production function of impact origin. Type 2 craters are mostly irregular shallow depressions and probably of various origins. Some of the type 2...

Carr, M.H.; Kirk, Randolph L.; McEwen, A.; Veverka, J.; Thomas, P.; Head, J.W.; Murchie, S.

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Year Published: 1993

Galileo observations of Post-Imbrium lunar craters during the first Earth-Moon flyby

Copernican‐age craters are among the most conspicuous features seen on the far side and western limb of the Moon in the Galileo multispectral images acquired in December 1990. Among the new morphologic observations of far‐side craters are bright rays, continuous ejecta deposits, and dark rings associated with probable impact‐melt veneers. These...

McEwen, Alfred S.; Gaddis, Lisa R.; Neukum, Gerhard; Hoffman, Harald; Pieters, Carle M.; Head, James W.

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Year Published: 1993

Velocity measurements and changes in position of Thwaites Glacier/iceberg tongue from aerial photography, Landsat images and NOAA AVHRR data

The Thwaites Glacier/iceberg tongue complex has been a significant feature of the Antarctic coastline for at least 50 years. In 1986, major changes began to occur in this area. Fast ice melted and several icebergs calved from the base of the iceberg tongue and the terminus of Thwaites Glacier. The iceberg tongue rotated to an east-west orientation...

Ferrigno, Jane G.; Lucchitta, Baerbel K.; Mullinsallison, A. L.; Allen, Robert J.; Gould, W. G.

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Year Published: 1993

Antarctic glacier-tongue velocities from Landsat images: First results

We measured the velocities of six glacier tongues and a few tongues within ice shelves distributed around the Antarctic coastline by determining the displacement of crevasse patterns seen on sequential Landsat images. The velocities range from less than 0.2 km a−1 for East Antarctic ice-shelf tongues to more than 2.5 km a−1 for the...

Lucchitta, Baerbel K.; Mullins, K.F.; Allison, A.L.; Ferrigno, Jane G.

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Year Published: 1992

Geologic map of the Memphis Facula Quadrangle (Jg-7) of Ganymede

No abstract available.

Lucchitta, Baerbel K.; Barnes, C.W.; Glotfelty, M.F.
Geologic map of the Memphis Facula Quadrangle (Jg-7) of Ganymede; 1992; I; 2289; Lucchitta, B. K.; Barnes, C. W.; Glotfelty, M. F.

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Year Published: 1992

Enhanced visualization for the interpretation of Magellan radar data: Supplement to the Magellan special issue

The differences of radar data from more familiar photographic images, coupled with the unique geologic characteristics of Venus's surface, can make interpretation of the standard Magellan data products difficult for both planetary scientists and nonspecialists. We describe a set of digital processing techniques for transforming individual remote‐...

Kirk, Randolph L.; Soderblom, Laurence A.; Lee, Ella M.

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Year Published: 1992

The geology and distribution of impact craters on Venus: What are they telling us?

Magellan has revealed an ensemble of impact craters on Venus that is unique in many important ways. We have compiled a data base describing the 842 craters on 89% of Venus' surface mapped through orbit 2578. (The craters range in diameter from 1.5 to 280 km.) We have studied the distribution, size‐density, morphology, geology, and associated...

Schaber, G.G.; Strom, R.G.; Moore, H.J.; Soderblom, Laurence A.; Kirk, Randolph L.; Chadwick, D.J.; Dawson, D.D.; Gaddis, L.R.; Boyce, J.M.; Russell, Joel F.

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Year Published: 1992

Lunar impact basins and crustal heterogeneity: New western limb and far side data from Galileo

Multispectral images of the lunar western limb and far side obtained from Galileo reveal the compositional nature of several prominent lunar features and provide new information on lunar evolution. The data reveal that the ejecta from the Orientale impact basin (900 kilometers in diameter) lying outside the Cordillera Mountains was excavated from...

Belton, Michael J.S.; Head, James W.; Carle m. Pieters; Greeley, Ronald; McEwen, Alfred S.; Neukum, G.; Klaasen, Kenneth P.; Anger, C.D.; Carr, M.H.; Chapman, C.R.; Davies, M.E.; Fanale, F. P.; Gierasch, P.J.; Greenberg, R.; Ingersoll, A.; Johnson, Torrence; Paczkowski, B.; Pilcher, C.B.; Veverka, J.

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Year Published: 1992

The canyon system on Mars

Individual Martian equatorial troughs are described, and their stratigraphy, geomorphology and structure are discussed. Possible origins and the overall sequence of events are addressed. Wall rock, interior layered deposits, irregular floor deposits, fractured floor material, and surficial deposits are examined. Chasma walls, wall stability, pits...

Lucchitta, Baerbel K.; McEwen, A.S.; Clow, Gary D.; Geissler, Paul E.; Singer, R.B.; Schultz, R.A.; Squyres, Steven W.

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Year Published: 1992

Lava-flow characterization at Pisgah Volcanic Field, California, with multiparameter imaging radar

Multi-incidence-angle (in the 25° to 55° range) radar data acquired by the NASA/JPL Airborne Synthetic Aperture Radar (AIRSAR) at three wavelengths simultaneously and displayed at three polarizations are examined for their utility in characterizing lava flows at Pisgah volcanic field, California. Pisgah lava flows were erupted in three phases;...

Gaddis, Lisa R.

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Year Published: 1990

Subsurface energy storage and transport for solar-powered geysers on Triton

The location of active geyser-like eruptions and related features close to the current subsolar latitude on Triton suggests a solar energy source for these phenomena. Solidstate greenhouse calculations have shown that sunlight can generate substantially elevated subsurface temperatures. A variety of models for the storage of solar energy in a sub-...

Kirk, Randolph L.; Brown, Robert H.; Soderblom, Laurence A.