From: Jet Propulsion Laboratory
Posted: Monday, March 25, 2002
Cruise activities continue for Galileo during our long, nearly 10 month period between encounters. During this time, the distance from the spacecraft to Jupiter increases from 290 to 320 Jupiter radii (20.7 million to 22.9 million kilometers or 12.9 million to 14.2 million miles). This breaks our previous distance record of nearly 290 Jupiter radii set in September 2000 during our 28th orbit of the giant planet.
The third of five cruise sequences of commands will be transmitted to the spacecraft on April 1, and these commands will control the activities on the spacecraft until June 2.
Routine hardware maintenance activities for the spacecraft this month include two exercises of the propulsion thruster system on March 29 and April 19, and an exercise of the tape recorder on April 12.
Tape playback of the final bits of data recorded during the January Io flyby and during the recent calibration activity should be complete by the April 12 tape maintenance. At the end of this activity, the tape recorder will be parked with the read/write heads near the center of the tape. This minimizes the stress on the spring that maintains the correct tension on the tape, and allows the tape to sit quietly and safely for long periods without moving. Except for monthly exercises of the tape to check its status, there are no further plans to use the tape recorder until the November Amalthea flyby.
On April 3 a test of the on-board gyroscopes is performed. These gyroscopes provide the spacecraft with information about its attitude in space when we perform turns and maneuvers. The electronics associated with the gyros have shown significant degradation over the years of exposure to the harsh radiation environment near Jupiter. However, when the spacecraft spends time farther away from Jupiter, the electronics have shown some tendency to heal themselves somewhat from these radiation effects, or anneal. This test will provide engineers with data about how much self-healing takes place after 2-1/2 months far from the radiation damage.
On April 11 the spacecraft will turn in place by 2.4 degrees to keep the communications antenna pointed towards the Earth.
With the spacecraft well outside the magnetosphere of Jupiter on the sunward side of the planet, continuous data collection by the Magnetometer, the Dust Detector, and the Extreme Ultraviolet Spectrometer instruments provides scientists with information about the interplanetary medium during this time.
For more information on the Galileo spacecraft and its mission to Jupiter, please visit the Galileo home page at one of the following URL's:
// end //