Galileo Europa Mission Status - April 9, 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 successfully completed its most recent flyby of Jupiter's moon Europa on March 29, and indications are there was no change to the gyroscope performance. Because one of the two gyros had been acting up, the closest approach to Europa was carried out in cruise mode, with the gyros turned off; the spacecraft used only stars to orient itself and point its instruments. However, an attitude-control system performance test showed that the gyros did not degrade further during this latest pass through Jupiter's intense radiation environment. Galileo project engineers have pinpointed a single computer chip as the cause of the anomalous behavior. This particular chip has received more radiation exposure than other similar chips in the gyro electronics.
This week, Galileo transmitted to Earth pictures and other science information gathered during the latest Europa flyby. This includes one of three observations by the photopolarimeter radiometer designed to refine temperature variation maps of Europa's surface. This will help scientists understand surface ages and composition and the process that may have formed the surface. In addition, there is information from instruments that study magnetic fields and charged particles on the interaction between Europa and Jupiter's magnetic and electric field environment. The camera and the near infrared mapping spectrometer have returned information on a region of dark lines and the Mannann'an crater on Europa. Data gathered by the spectrometer of the south pole of Jupiter's volcanic moon, Io, provides the spacecraft's best view of the area until late 1999.
On Friday, April 10, the spacecraft will perform regular propulsion system maintenance and perform a turn to keep its radio antenna pointed toward Earth.
Galileo's next Europa flyby will take place on May 31, 1998, at an altitude of 2,521 kilometers (1,566 miles). The spacecraft successfully completed its primary mission in December 1997 and is now in its two-year extension, the Galileo Europa Mission. Current plans include four more Europa flybys after the May encounter, four Callisto flybys, and one or two of Io, depending on spacecraft health.
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