It is now 2 days, 3 hours to the Galileo spacecraft’s next
encounter with Jupiter’s volcanic moon, Io.

A special Countdown to Io home page is now available on the
Galileo Home Page:

Launched in October 1989, Galileo entered orbit around
Jupiter in December 1995, and completed its primary 2
year orbital tour around the solar system’s largest planet.
Galileo has since embarked on a two-year extended mission,
called the Galileo Europa Mission (GEM). During GEM,
Galileo had already made 8 close encounters with Europa, 4
with Callisto and one Io flyby. The spacecraft will end the
GEM mission with one final encounter with Io.

The 14th and final encounter for GEM is scheduled for Io on
November 26, 1999 at 4:05 UT (or 4:40 UT Earth Receive
Time). Referred to as Io 25, since this will occur on the
25th orbit since Galileo entered orbit around Jupiter, this
encounter will be Galileo’s closest ever flyby of Io. With a
diameter of 3,630 km, Io is about the same size of our own
Moon, and is the most volcanically active body in our solar
system. On the upcoming encounter, the Galileo spacecraft
will approach Io on its night side and pass by the satellite at
a distance of only 300 km (186 miles) and pass over Io’s
south pole.

Highlights of the Countdown to Io home page:

o A virtual flyby of Io with computer-generated approach
images of Jupiter and Io displayed at the top of the home
page. These images are all updated every 5 minutes in
sync with the actual flyby by the spacecraft.

o Simulated animation of the Io 25 flyby.

o Daily Galileo status reports reporting on the Io 25
encounter. o Fact sheets and Europa, Callisto and Io.

o A detailed timeline of events and sequences that the
spacecraft will perform for the Io 25 encounter.

o Voyager 1 & 2 images of Callisto, Ganymede, Europa and
Io. o Hubble Space Telescope images of the Galilean

o Pioneer 10 & 11 images of Callisto, Ganymede, Europa and