Four Weeks on Galileo February 25 – March 24, 2002

Galileo operations have returned to normal after recovery from an
unexpected safing event on the spacecraft last week. A Command and Data
System computer reset occurred on Saturday, February 1, which caused the
spacecraft to shut down operations and phone home for help. We believe that
similar resets, which have occurred since 1998, are due to accumulated
radiation effects, so we were somewhat surprised that this one occurred so
far out from Jupiter and its intense radiation field. At the time of the
reset, the spacecraft was nearly 180 Jupiter radii (12.9 million kilometers
or 8 million miles) from the planet. This most recent event may be more
similar to anomalies that occurred during Galileo’s interplanetary cruise,
prior to arrival at Jupiter in 1995. This just goes to show that space
exploration is unpredictable at best!

The flight team continues to look for new methods of making the spacecraft
more robust and resistant to these resets. During our final flyby of
Amalthea coming up in November, Galileo will experience a radiation
environment many times more intense than any we have yet seen.

On Thursday, March 7, routine maintenance of the spacecraft propulsion
system is performed. On Friday, March 15, routine maintenance of the tape
recorder is performed.

Playback of the tape recorded data from the January 17 flyby of Io
continues. In addition, data remaining on the tape from the October flyby
is still available for playback. Continuous data collection by the
Magnetometer, the Dust Detector, and the Extreme Ultraviolet Spectrometer
instruments also occupies our attention.

Plans are also being made to perform a final set of calibrations for the
Near Infrared Mapping Spectrometer and the Solid State Imaging camera.
These calibrations will take place Monday night, March 18. They will
provide a final measurement of the sensitivity of the instruments against
which we can compare recent science measurements.