This Week on Galileo
October 21-27, 2002
The Pace Quickens
The science observation sequence for Galileo's final satellite encounter
begins this week. On Monday, October 21, the Fields and Particles suite of
instruments is turned on and configured to collect continuous data for the
next three weeks. During this time, the spacecraft passes the tiny inner
moon Amalthea, and passes closer to Jupiter than any spacecraft since
Pioneer 10 and 11 sped by nearly three decades ago. The instruments
participating in the Galileo data collection are the Dust Detector, the
Energetic Particle Detector, the Heavy Ion Counter, the Magnetometer, the
Plasma Subsystem, and the Plasma Wave Subsystem.
While these data are being collected, occasional gaps in the ground
communications antenna coverage require the data to be stored in an
on-board computer memory buffer, and when that buffer fills, the data are
copied onto the tape recorder for later playback. To prepare for these
buffer dumps, the tape is moved on Monday to the correct position to begin
recording. Over the next two weeks the buffer is dumped to tape 14 times.
On Thursday, October 24, a test of the gyroscopes that help determine the
spacecraft attitude is performed. This test will help engineers decide if
any of the software parameters that are used to process the gyro data need
to be updated before the maneuver that will occur next week.
On Friday, October 25, routine maintenance of the propulsion system is
performed. Also on that day the spacecraft closes to within 100 Jupiter
radii (7.1 million kilometers or 4.4 million miles) of the giant planet.
Finally, on Sunday, October 27, the sequence of commands that will govern
spacecraft activity during the week of the close Amalthea flyby will be
transmitted to Galileo.