PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011

FOR IMMEDIATE RELEASE                                                March 1, 1991


       The Magellan spacecraft will resume full radar mapping of Venus early Saturday, ending a temperature control strategy that cut alternate mapping swaths by 10 minutes, project officials at NASA's Jet Propulsion Laboratory said today.

       The command to resume the full 37-minute mapping swath was to be sent to the spacecraft late today.

       The temperature control maneuver was needed for three weeks because the spacecraft was in full sunlight throughout each of its orbits around Venus and kept some spacecraft components from passing temperature alarm limits.

       Magellan is now in the shadow of the planet for part of each orbit which results in cooling, flight controllers said,.

       As the geometry of the planets relative to the sun changes again in mid April, however, another temperature control strategy will be implemented.

       That strategy is called "Two Hide." It will put part of the spacecraft in the shade of the high-gain antenna twice during each orbit to keep electronic components cool.

       The strategy is expected to be required for four weeks at the end of the primary mission, Project Manager Tony Spear said.

       Since the period in the shaded position will reduce the time used for acquisition and playback of data, the strategy will result in image losses of about 2 percent of the surface area of Venus, he said. Magellan will still map 82 percent of Venus during its first cycle around the planet.


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3/1/91 JJD
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