Galileo is a NASA spacecraft mission to Jupiter, launched October 18, 1989, and designed to study the planet’s atmosphere, satellites and surrounding magnetosphere for two years, starting December 1995.
This mission will be the first to make direct measurements from an instrumented probe within Jupiter’s atmosphere, and the first to conduct long-term observations of the planet and its magnetosphere and satellites from orbit around Jupiter. It is already the first to encounter an asteroid, and to photograph an asteroid’s moon.
The Galileo Europa Mission (GEM) is a highly focused follow-on to Galileo’s Jupiter system exploration, and a precursor for future missions to two of Jupiter’s moons, Europa and Io. GEM will conduct a detailed study of Europa over 14 months, then plunge repeatedly through the Io Plasma Torus to reach volcanic Io.