The venus radar mapper mission

Dallas, S. S.

doi:10.1016/0094-5765(87)90010-5

Cited by 4 publications

(1 citation statement)

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“…the time this map was prepared, but they will be valuable for geologic mapping (Campbell et al, 1989a(Campbell et al, , 1989cArvidson et al, 1990). Data from Magellan, scheduled for insertion into orbit around Venus in August 1990, will extend coverage to at least lat 70* S. and increase resolution by nearly an order of magnitude over that of existing images (Dallas, 1987;Saunders, 1988).…”

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Geologic/geomorphic and structure maps of the northern quarter of Venus

Schaber¹,

Kozak²

1990

Open-File Report

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1. Geologic/geomorphic map of the northern quarter of Venus 2. Structure map of the northern quarter of Venus MAP COMPILATION The two sheets in this map set are the first step in a research project funded by the National Aeronautics and Space Administration (USGS Contract W15,814). The main goal of the project is to investigate the geologic evolution of Venus. The maps were a planned prerequisite to that project in order that local study areas could be placed in chronologic and regional geologic context. Because of the interest in Venus due to the Magellan Mission, the open-file format was chosen to expedite availability before imaging data begin to arrive from the spacecraft in August 1990. A map of the same region by Soviet authors (Sukhanov et al., 1989), which shows an alternative interpretation, has been published under a joint U.S./U.S.S.R. cooperative effort (Basilevsky et al., 1989).These maps are the result of a photogeologic interpretation of images from the first medium-resolution orbital imaging radar survey of the northern quarter of Venus. The images were acquired by the two Soviet spacecraft Venera 15 and 16 in 1983-84. Except in a few small areas, previous data were insufficient for geologic mapping, allowing only general statements to be made Pettengill et al., 1980;McGill et al., 1983). The resolution of 1-2 km obtained by the Venera synthetic aperture radar (SAR) system is comparable with that of images of Mars obtained by Mariner 9. The Venera SAR instrument, however, "illuminated" the surface at a constant angle (13 degrees off nadir) with 8-cm-wavelength microwave energy and recorded the backscattered albedo, whereas Mariner 9 recorded visible wavelength albedo at varying solar illumination angles. Thus, references made herein to light or dark albedo on the Venera images indicate some combination of slope, roughness, or reflectivity differences at the surface. (See Avery and Berlin (1985), Simonett andDavis (1983), andElachi (1987) for progressively detailed discussions on radar imaging and interpretation and Ford et al. (1989) for a treatment of image analysis as pertaining specifically to Magellan data.)The area imaged by the Venera craft (115xlCP knr) and mapped here (111.4xlCP km2 ) covers the 25 percent of Venus centered on the north pole. Processing and mosaicking of the radar data Bogomolov et al., 1985;Bockstein et al., 1988) were done by the Institute for Information Transmission Problems of the U.S.S.R. Academy of Sciences. We mapped the geology and structure at a reconnaissance level on the 27 l:5,000,OOC^scale quadrangles that resulted (U.S.S.R. Academy of Sciences, 1987Sciences, ,1988; we then compiled this geology and structure on the l:15,000,000-scale image mosaic prior to transferring it to an airbrush rendition of the mosaic (U.S. Geological Survey, 1989, sheet 2). (See NOTES ON BASE.) Supplementary data used in mapping include a topographic dataset of combined Pioneer Venus and Venera altimetry data (E. Eliason, oral communication, 1990). This dataset was used to create...

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Geologic/geomorphic and structure maps of the northern quarter of Venus

Schaber¹,

Kozak²

1990

Open-File Report

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Challenges in navigation of the venus radar mapper (VRM) spacecraft

Mohan

1986

Acta Astronautica

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Block adaptive quantization of Magellan SAR data

Kwok

Johnson

1989

IEEE Trans. Geosci. Remote Sensing

177

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Aktract-This paper reports on a data compression scheme which will be used to reduce the SAR data rate on the U.S. NASA Magellan (MGN) mission to Venus. The MGN spacecraft has only one scientific instrument: A radar system used for imaging the surface, for altimetric profiling of the planet topography, and for measuring radiation of the planet surface. A straightforward implementation of the scientific requirements of the mission results in a data rate higher than can be accommodated by the available system bandwidth. A data-rate reduction scheme which includes operation of the radar in burst mode and block adaptive quantization of the SAR data is selected to satisfy the scientific requirements. Descriptions of the quantization scheme and its hardware implementation is given here. Burst-mode SAR operation is also briefly discussed.

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The venus radar mapper mission

Cited by 4 publications

References 1 publication

Geologic/geomorphic and structure maps of the northern quarter of Venus

Geologic/geomorphic and structure maps of the northern quarter of Venus

Challenges in navigation of the venus radar mapper (VRM) spacecraft

Block adaptive quantization of Magellan SAR data

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