Galileo Europa Mission Status - July 23, 1998
MEDIA RELATIONS OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011 http://www.jpl.nasa.gov
Galileo project engineers sent up commands last night that successfully re-started functioning of the second of the spacecraft's two, identical command and data subsystems. This means that both subsystems are now working redundantly, as they are designed to do. Engineers will re-start the science processing function tonight, but it may take up to a week for the spacecraft to resume transmitting science data to Earth.
The subsystems, which receive commands from Earth and transmit data to the ground, started behaving anomalously on Monday, during the latest flyby of Jupiter's icy moon Europa. When one of the spacecraft's command and data subsystems detected a problem, a built-in, fault-protection routine was activated, which put the spacecraft in a "safe" mode. Galileo project engineers believe the anomaly was triggered when debris shorted a signal line, causing multiple resets. Although these resets have occurred individually at some point during Galileo's mission, it was a fluke that several occurred at about the same time. Because of the anomaly, nearly all data from this week's Europa flyby were lost.
An abundance of Europa data and pictures have already been gathered by Galileo during flybys of both its primary and extended missions. The spacecraft successfully completed its two-year primary mission in December 1997, and is currently in the midst of a two-year extended mission. This current flyby was the fifth of the extended mission, with three more Europa flybys scheduled, including one on Sept. 26.
The Galileo Europa Mission is managed by JPL for NASA's Office of Space Science, Washington, D.C.
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