Galileo was an unmanned spacecraft that studied the planet
Jupiter and
its moons, as well as several other Solar System bodies. Named after the astronomer
Galileo Galilei, it consisted of an orbiter and entry probe. It was launched on October 18, 1989, carried by
Space Shuttle Atlantis, on the
STS-34 mission.
Galileo arrived at Jupiter on December 7, 1995, after
gravitational assist flybys of
Venus and
Earth, and became the first spacecraft to orbit Jupiter. It launched the first probe into Jupiter, directly measuring its
atmosphere. Despite suffering major antenna problems,
Galileo achieved the first
asteroid flyby, of
951 Gaspra, and discovered the first
asteroid moon, Dactyl, around
243 Ida. In 1994,
Galileo observed
Comet Shoemaker–Levy 9's collision with Jupiter. The spacecraft was an international effort by the
United States of America and the Federal Republic of
Germany.