This Week on Galileo October 7-13, 2002
and there is now less than a month until Galileo
makes its final fly-by of the mission, a close encounter with Jupiter’s
small inner satellite Amalthea, on November 5. As the pace of activity
picks up, both on the spacecraft and on the ground, the pace of these
reports now returns to weekly.
The flight team is now hard at work putting the finishing touches on the
activity sequence for the encounter, and planning for contingency actions.
The harsh environment near Jupiter has upset our plans in the past, and we
are relying on our 12 years of experience with the spacecraft, and our
anticipation of the worst that Jupiter can throw at us, to shore up any
vulnerabilities in our plans.
On Friday and Saturday, October 4 and 5, a test was performed to verify a
method of maintaining Galileo’s knowledge of its position and spin rate
deep within Jupiter’s high radiation environment. High radiation levels
interfere with the star scanner, which uses the positions of bright stars
to determine Galileo’s attitude and position. To counter this effect,
Galileo’s attitude control computer is told to “hibernate” for several
hours, allowing it to continue reporting pointing and spin rate of the
spacecraft without relying on either the star scanner or its
radiation-sensitive gyros.
On Friday, October 11, Galileo performs the last update to its orientation
prior to the encounter. This is a fairly large turn in place of slightly
over 9 degrees, to keep the communications antenna pointed towards Earth,
and simultaneously to orient the spacecraft to take the best advantage of
the geometry of the flyby for the measurements to be taken by the Fields
and Particles instruments. The spacecraft will remain at this orientation
until the end of planned mission operations in mid-January 2003.
Ongoing activities for the spacecraft include maintaining the condition of
the on-board tape recorder and continued data collection by the Dust
Detector, the Magnetometer, and the Extreme Ultraviolet Spectrometer
instruments.
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:
