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                                                                        November 12, 1990


       Tomorrow NASA's Galileo spacecraft will carry out its fifth trajectory-correction maneuver since its Venus gravity assist last February.

       The maneuver will aim Galileo for its Earth gravity assist flyby December 8 at 12:35 p.m. PST, at an altitude of 593 miles (952 kilometers) above the southwest Atlantic.

       The operation, calculated and programmed by the Galileo flight team at the Jet Propulsion Laboratory, will change the spacecraft's velocity in its solar orbit by 1.3 meters per second or about 2.9 mph.

       This compares with speed changes of almost 5,000 mph in February's Venus gravity assist, 55 mph in the first maneuver after that, and about 11,500 mph during the Earth gravity assist next month.

       One final maneuver is scheduled for November 28 to precisely refine the Earth approach trajectory. Small errors in the Earth approach would be magnified greatly by the flyby, requiring larger maneuvers afterwards. The final corrective maneuver scheduled on Venus approach was cancelled because Galileo's navigation was so accurate.

       The Galileo mission is being carried out and managed for NASA's Office of Space Science and Applications by the Jet Propulsion Laboratory. Its destination and objective is the planet Jupiter; the Earth gravity assist helps build up velocity needed to reach Jupiter in 1995.


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9/12/90 JHW
#1329