From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Newsgroups: sci.space.news
Subject: Year's End on Galileo - December 30-31, 2000
Date: 30 Dec 2000 21:00 UT
Organization: Jet Propulsion Laboratory
Approved: sci-space-news@zagami.jpl.nasa.gov
Message-ID: <30DEC200021001020@kelvin.jpl.nasa.gov>

                            Year's End on Galileo
                            December 30-31, 2000

The end of the year 2000 finds the Galileo spacecraft starting to wrap up
another encounter with the Jovian system. The spacecraft's Solid-State
Imaging (SSI) camera takes the stage over the weekend, with only a few
observations being performed by the Near-Infrared Mapping Spectrometer
(NIMS).

The NIMS observations total seven in number. The first is dedicated to the
monitoring of volcanic activity on Io, while the remaining six are designed
to map the entire disk of Jupiter from north to south and across the full
range of longitudes. This global map will provide additional information on
the composition and dynamics of Jupiter's clouds.

As reported in earlier editions of Today on Galileo, Cassini is flying past
Jupiter on its way to arrival at Saturn in 2004. The dual-spacecraft nature
of these and other joint observations provide scientists with a unique
opportunity to examine phenomena as seen from two different viewpoints. This
kind of opportunity is a rarity in deep space missions.

SSI fills the remainder of the weekend with a total of 24 observations. Two
of these observations capture global color views of Io, and are also used to
look for changes on Io's surface caused by recent volcanic activity. SSI
then makes two observations of Jupiter's main ring. These observations are
designed to look at the ring under lighting conditions that yield
information about the size of ring particles. The observations will also
shed light on some unexpected patchiness seen within the ring in previous
observations.

SSI dedicates a total of eight observations to capture a series of images of
Io while eclipsed from the Sun by Jupiter. These images are expected to
yield new science results on atmospheric emissions, volcanic plumes, and
surface hot spots. The use of both clear and infrared filters for the SSI
images will allow the temperatures of hot spots to be measured. A set of
images is taken every 17 minutes throughout the two-hour eclipse period.

The last 12 observations performed by SSI are dedicated to a campaign to
observe a turbulent region just northwest of Jupiter's Great Red Spot. This
region is particularly active and has been the site of thunderstorms in
previous observations. The region will be observed over four Jupiter
rotations, three of which are completed Sunday. Jupiter rotates on its axis
once every 10 hours, so one set is taken early in the morning, the next is
taken at midday, and the last is taken late at night. Observing over
successive rotations will allow scientists to study the evolution of these
storms over longer time scales than previous observing campaigns.

What is in store for Galileo in the first week of 2001? Come back tomorrow
for the return of This Week on Galileo!

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:

http://galileo.jpl.nasa.gov
http://www.jpl.nasa.gov/galileo