Galileo Europa Mission Status - May 14, 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 has spent the week processing and transmitting to Earth pictures and science information gathered during its March 29 flyby of Jupiter's moon Europa. The material had been stored on the spacecraft's onboard tape recorder.
Some of the information would have been transmitted last week, but it was delayed in the name of science when the Galileo team gave up some antenna time at the Deep Space Network's 70- meter (230-foot) antenna in Canberra, Australia. The antenna was needed to support radio frequency observations of a newly identified gamma ray burst.
Included in this week's batch of information transmitted to Earth by Galileo are two images of a region of Europa notable for its dark spots. Together, these images provide a stereo topographic view of the area. Another observation measures the varying light intensities on Europa, information which helps scientists identify different surface materials. An observation from Galileo's near-infrared spectrometer should provide more information on the materials that make up the region of Europa which has dark spots and pull-apart wedge sections.
The spacecraft is sending back previously recorded information that will beef up knowledge of the interaction between Jupiter's magnetic and electric fields and Europa.
Last week, the Galileo team modified the spacecraft's onboard attitude control software. However, the adjustment did not change the gyroscope's behavior as the team had hoped. A second modification was made Wednesday, May 13, and early tests indicate that the procedure was a success. Another gyro performance test is scheduled this Friday, May 15, and the Galileo team expects it will confirm that the attitude control system is now performing as planned. The attitude control system has been behaving anomalously since the spacecraft's closest flyby to Europa last December 16. The Galileo team has been able to operate the spacecraft in such a way that the anomaly has had very little effect on the spacecraft's performance. Nonetheless, engineers continue to analyze the situation, which they believe is related to the spacecraft's repeated exposure to Jupiter's strong radiation.
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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