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       Scientists on NASA's Magellan mission will discuss new findings about the surface and crust of Venus and the need for future exploration of Earth's sister planet on Dec. 7, during the 1994 fall meeting of the American Geophysical Union in San Francisco.

       New results from analysis of the gravity data provided by the spacecraft shows Venus may have a thick, strong lithosphere that is different from what scientists had previously believed before Magellan completed its mapping mission earlier this year.      

       Dr. Ellen Stofan, who was deputy project scientist on the project, will discuss the kinds of future exploration that scientists would recommend as a follow-up to Magellan.

       Others on the panel at the noontime news conference will include Dr. Steve Saunders, project scientist; Dr. Roger Phillips of Washington University in St. Louis; and Dr. Sean Solomon of Carnegie Institution, Washington, D.C.

       The successful five-and-a-half year mission to map the surface and measure the gravity of Venus ended October 12, 1994, when ground controllers lost contact with the spacecraft. It is believed the spacecraft burned up in the atmosphere later the same day.

       The loss of signal, which was anticipated, was due to low power on the spacecraft. During its final descent, the spacecraft gathered scientific data on the planet's upper atmosphere, including dynamic interactions with it, by orienting its wing-like solar panels in opposite directions like the sails of a windmill.

       Magellan was launched in May 1989 and entered orbit around Venus in August 1990. It gathered data for more than four years and exceeded all of the mission objectives many times over.

       Using imaging radar, Magellan mapped 98 percent of the planet's cloud-covered surface and compiled a high-resolution, comprehensive gravity map of 95 percent of the planet. The gravity data allow scientists to see the interior of the planet and compare that knowledge of the interior to the surface features revealed by Magellan's radar images.

       Magellan also performed a first-of-a-kind "aerobraking" maneuver by dipping into the atmosphere to reshape its orbit. The aerobraking technique is being used in the design of the 1996 Mars Global Surveyor mission to enable a smaller, less expensive spacecraft to enter orbit around Mars in 1997, using much less fuel than would otherwise be required.

       The Magellan mission was managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, Washington, D.C.


12/7/94 JJD