Galileo spacecraft
Color Mosaic and Active Volcanic Plumes on Io
Galileo spacecraft

Galileo spacecraft

Courtesy of NASA

Galileo was launched from the space shuttle Atlantis and sent on a 2-year mission to study Jupiter and its moons. The spacecraft had two parts—an orbiter and a probe. The probe parachuted down to Jupiter’s surface to study the atmosphere and returned data until it melted in the heat, about 1 hour later. The orbiter extended its mission and gathered data for almost 8 years, before it was purposely crashed into Jupiter’s surface in 2003.

October 18, 1989

December 7, 1995

End of Mission
September 21, 2003

Collect data on the magnetosphere and study Jupiter and its moons. Study Venus, Earth, the Moon, and two asteroids, Gaspra and Ida, during flybys.

Galileo discovered a tiny moon, Dactyl, orbiting the asteroid Ida.

When Comet Shoemaker-Levy 9 crashed into Jupiter, Galileo was in position to directly observe the collision.

Galileo’s probe detected an atmosphere that was drier than expected and measured winds of 724 kilometers per hour (450 mph) before melting and vaporizing 58 minutes later.

Galileo’s orbiter found evidence of subsurface saltwater on Europa, Ganymede, and Callisto, and revealed the intensity of volcanic activity on Io. The spacecraft was purposely put on a collision course with Jupiter to eliminate any chance of an unwanted impact between the spacecraft and Jupiter’s moon Europa. Galileo found that Jupiter’s moon Amalthea is a pile of icy rubble less dense than water, instead of denser rocky material. This finding shakes up long-held theories of how moons form around giant planets.