May 20 - June 16, 2002
The Next Four Weeks on Galileo
The Galileo spacecraft proceeds in its measured pace around the giant
planet Jupiter while the flight team continues to diagnose a problem with
the on-board tape recorder. On April 12, during a routine maintenance
activity, the tape appears to have stuck to the record or playback heads.
Four tests have been performed to characterize the problem. On Wednesday,
May 22, one final low-speed test will be executed. Based on these results,
our efforts will now become more aggressive, possibly trying to move the
tape at higher speeds, which should provide more "oomph" to pulling the
tape free. Detailed plans for the subsequent tests have not been scheduled
as yet, and in the meantime all regularly scheduled tape activities have
been put on hold until we have demonstrated that the machine is working
On Saturday, May 25, the spacecraft performs a 4 degree turn in place to
keep the communications antenna pointed towards Earth.
On Friday, May 31, routine maintenance of the propulsion system is performed.
On Monday, June 3, the fourth planned load of sequence commands takes over
control of the spacecraft, and will govern Galileo's activities until
On Wednesday, June 5, a test of the on-board gyroscopes will be performed.
These gyros have shown sensitivity to the intense radiation environment
seen near Jupiter, but gradually correct themselves with time spent in the
more benign environment far from the planet. This calibration will
determine the health of the gyros in preparation for an orbit trim maneuver
planned for Friday, June 14. This propulsive engine burn takes place one
day after apojove, the farthest point in Galileo's orbit from Jupiter. This
is the most distant that Galileo has been from Jupiter since before
arriving in orbit in December 1995. At 348.1 Jupiter radii from the planet
(24.9 million kilometers or 15.5 million miles) this is approximately one
sixth of the distance from Earth to the Sun, and it takes light nearly a
minute and a half to speed from Jupiter to the spacecraft!
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.