Galileo Europa Mission Status - July 21, 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
The Galileo spacecraft experienced an anomaly during its latest flyby of Jupiter's moon Europa. Neither the spacecraft nor its instruments are in immediate danger. During this encounter, a problem was detected by one of the spacecraft's two command and data subsystems, which receive commands from Earth and send back telemetry, or data from the spacecraft. Because of this, a built-in, fault-protection routine was activated, which put the spacecraft in a "safe" mode. That means the anomalous command and data subsystem was shut down, and control was turned over to the identical, second command and data subsystem. The second subsystem also detected a problem, but it is programmed to remain active as long as the first subsystem is not functioning normally.
At 11:14 a.m. Pacific time on Monday, July 20, the problem was reported to ground controllers, and telemetry was initially lost. By 11:35 p.m. Pacific time, engineering telemetry from the spacecraft had been restored and communications are continuing.
Engineers have activated a recovery process designed to tell them why the problem occurred; it is expected to restore full functioning to both command and data subsystems. Because of the anomaly, nearly all the data from yesterday's Europa flyby were lost and no science data will be gathered until the anomaly is corrected.
Galileo successfully completed its two-year primary mission in December 1997, and is currently in the midst of its two-year extended mission. This current flyby was the fifth of the extended mission. Three more Europa flybys are scheduled, with the next one on Sept. 26. A wealth of data and pictures of Europa have already been gathered during flybys of both the primary and extended missions.
The Galileo Europa Mission is managed by JPL for NASA's Office of Space Science, Washington, D.C.
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