Status Report

This Week on Galileo 5-11 March 2001

By SpaceRef Editor
March 6, 2001
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This week sees the Galileo spacecraft execute two routine maintenance
activities and pass a geometrical milestone. On Wednesday, the spacecraft
performs a calibration of its gyroscopes, which help to determine which way
the spacecraft is pointed. Over the past five years, exposure to the
intense radiation environment near Jupiter has caused the electronic
components that operate and measure the gyros to degrade and report
incorrect data to the spacecraft computers. This calibration provides
information that allows engineers to calculate numerical corrections to
load into the spacecraft software so that the erroneous signals sent out by
the gyros are seen as correct.

On Thursday, routine maintenance on the spacecraft propulsion system is

On Sunday, the spacecraft reaches its most distant point from Jupiter
during this orbit. This point, called apojove, is at a distance of 216.6
Jupiter radii, or nearly 15.5 million kilometers (9.6 million miles). This
is about 40 times the separation between the Earth and the Moon. At this
distance, it takes light 51 seconds to travel between the giant planet and
the spacecraft!

This week’s playback of the data stored on the tape from the December 28
flyby of Ganymede continues the series of observations begun last week. The
Near Infrared Mapping Spectrometer (NIMS) will complete the playback of its
observation of Jupiter’s south polar aurora and return an observation of a
White Oval storm in Jupiter’s atmosphere. The White Oval is the last
remnant of three such ovals that have merged over the past two years. A
portion of a global mosaic of Jupiter will also be returned. This mosaic
will be compared with data from the Cassini Visual and Infrared Mapping
Spectrometer, which was observing Jupiter at the same time. The last in a
series of three observations of Io will complete the infrared monitoring of
that satellite’s volcanic activity during this orbit.

The Solid State Imaging camera (SSI) will continue returning global color
images of Io, in cooperation with the Cassini imaging experiment. Pictures
taken of Jupiter’s main ring system will provide information on the ring’s
vertical structure and patchiness, and will provide an interesting
comparison to Cassini pictures taken at the same time, but from a different
viewpoint. This should give scientists a unique stereo view of these
fascinating features.

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:

SpaceRef staff editor.