This Week on Galileo
January 8-14, 2001
Galileo completes week eleven of a 14-week-long survey of the Jovian magnetosphere
The second week of the new millennium finds Galileo completing week
11 of a 14-week-long survey of the Jovian magnetosphere. Playback of
data stored during the spaceraft's December, 2000 passage through the
Jupiter system is not scheduled to start until early next month. One
engineering activity is performed by Galileo this week. On Monday,
the spacecraft performs standard maintenance on its propulsion
The survey of the Jovian magnetosphere is being performed by
Galileo's Fields and Particles instruments. The Fields and Particles
instruments are comprised of the Dust Detector, Energetic Particle
Detector, Heavy Ion Counter, Magnetometer, Plasma Detector, and
Plasma Wave instrument. The survey was initiated in late October,
2000 in conjunction with instruments on the Cassini spacecraft.
Cassini flew past Jupiter on December 30. Although Cassini was
generally expected to remain outside the magnetosphere until after
the flyby, measurements indicate that it entered the bow shock region
on December 27. In combination with Galileo measurements, this event
may provide new information on the behavior of the magnetosphere.
Galileo, on the other hand, has flown from the solar wind, into the
Jovian magnetosphere, and is now flying back out into the solar wind.
These joint studies with the Cassini spacecraft will yield
information on the interaction between the solar wind and Jupiter's
Galileo's survey data are recorded by its onboard tape recorder six
times this week. Typically, these data are almost immediately
packaged and transmitted to Earth. However, radio antennas of the
Deep Space Network (DSN) are scheduled to listen to Galileo for only
about 106 hours this week (out of a total 168 hours possible). In
its place, the spacecraft makes use of a data buffer (a section of
computer memory) to store up to seven hours of survey data at one
time. When the buffer is full, and the DSN is not listening, the
data are recorded by the tape recorder to prevent data loss.