The Legacy of Galileo - Keck Institute for Space Studies - Caltech

Challenging the Paradigm: The Legacy of Galileo
the mission’s name from its study designation of Jupiter Orbiter Probe (JOP) to Galileo, the
obvious choice.
The launch of Galileo was delayed for some years from its original target of January 1982, first
by delays in the development of the Space Transportation System, or Space Shuttle, which
was to carry Galileo and its upper stage rocket into space, and then by the tragic loss of the
Challenger and its crew in 1986. During this time, the stunning discoveries from the Voyager
flybys were being analyzed in depth and Galileo’s mission plans and experiment strategies
modified to respond to the new information. Finally, on 18 October, 1989, Galileo was
successfully launched aboard STS-34 Atlantis. Using a gravity assist trajectory that took it by
Venus and the Earth twice, Galileo arrived at Jupiter a little over six years after launch, on 7
December, 1995. After using its propulsion system to enter orbit about Jupiter, Galileo spent
seven years studying the system in three phases: the two year primary mission, and two
extended missions, the Galileo Europa Mission and the Galileo Millennium mission, ending
with a planned impact in 2003 into Jupiter to avoid any possibility of contamination of Europa
by a future inadvertent impact. During each orbit, the Galileo was targeted to make a close
flyby of one of the Galilean moons, to make high-resolution observations and to modify the
orbit, while making observations of Jupiter and the other moons as well. Figure 4 shows
Galileo’s trajectory and the time of each of these targeted satellite flybys as Jupiter and its
new artificial moon journeyed around the Sun.
Figure 4: Galileo’s trajectory.
24