This Week on Galileo - January 26 - February 1, 1998
This week Galileo continues to transmit to Earth pictures and science data acquired and stored on the onboard tape recorder during the spacecraft's close flyby of Jupiter's moon Europa in December 1997. Meanwhile, here on Earth, flight team members continue to examine engineering data gathered during a test of the spacecraft's attitude control system that was performed about a week and a half ago. The attitude control system has behaved anomalously on two occasions since December 1997. Preliminary findings seem to confirm initial theories that the anomalous behavior was caused by a hardware error in one of the spacecraft's two gyroscopes. Work on confirming these findings will continue throughout the week.
Scheduled for transmission to Earth this week are the final portions of the fields and particles' observation of the interaction between Europa and Jupiter's magnetic and electric field environment. There are also observations by Galileo's camera of the wedged regions of Europa and science information from the Near Infrared Mapping Spectrometer (NIMS) of the same wedged region of Europa. The NIMS data will help scientists learn about the types of materials found in this wedged region. Other NIMS observations to be returned this week monitor changes in Io's surface activity. This monitoring will aid observation planners later in the Galileo Europa Mission, when the spacecraft approaches its close flyby of Io in late 1999. Finally, the Photopolarimeter Radiometer team returns data from an observation designed to look for hot regions on Europa.
Once processing and transmission of these observations are completed, the spacecraft starts with re-processing and re-transmission of observations that may have previously been processed and transmitted to Earth. This second "pass" through the recorded data provides the science teams with the opportunity to fill up gaps in information caused by transmission problems the first time around. The second pass also provides the opportunity to re-play portions of observations that have been identified as particularly interesting or to simply add additional data from a particular observation.
First on the re-transmission schedule we find an observation of Ganymede's Gilgamesh region. This observation is expected to help determine the age of Europa's surface by allowing scientists to compare the number and types of craters in this region of Ganymede's surface to the crater statistics on Europa's surface. The last observation on this week's schedule is a global observation of Europa performed by NIMS.