Galileo

Spacecraft· NASAinactive

Galileo — first spacecraft to orbit Jupiter (1995–2003), studying the giant planet and its Galilean moons; ended with a planned plunge into Jupiter.

Open in 3D viewSee Galileo in the live, interactive 3D map

Key facts

Current speed

5.72 km/s

Distance from Sun

5.25 AU

Status

Completed

Launched

1989

Mission & specifications

Mission

Operator: NASA
Launched: October 18, 1989
Status: Completed

Trajectory

Current speed: 5.72 km/s
Distance from the Sun: 5.25 AU
Distance from Earth: 6.22 AU
Distance from Jupiter: 6,485,925 km

Cost & funding

Program cost: $1.60 × 10⁹ USD

Mission

Galileo was the first spacecraft to orbit Jupiter, and it transformed the giant planet and its moons from points of light into worlds. Released from the Space Shuttle Atlantis on 18 October 1989, it took a roundabout, six-year path to Jupiter, using gravity assists from Venus and Earth to build up speed. Along the way it made the first close flybys of asteroids, and at the asteroid Ida in 1993 it discovered Dactyl, the first moon ever found orbiting an asteroid. In 1994 it had a unique vantage point to watch the fragments of comet Shoemaker-Levy 9 slam into Jupiter. Galileo suffered a serious setback when its main antenna failed to unfurl, forcing engineers to squeeze the entire mission's data through a much smaller backup antenna using clever compression. It still delivered. On arrival in December 1995, it dropped a probe that plunged into Jupiter's atmosphere — the first ever to sample the air of a giant planet directly — while the main craft settled into orbit. Over nearly eight years and dozens of loops through the Jovian system, Galileo returned evidence that a salty ocean lies beneath the icy crust of Europa, watched the volcanoes of Io erupt, and discovered a magnetic field around Ganymede. To ensure it could never crash into and contaminate the potentially habitable Europa, controllers deliberately steered Galileo into Jupiter on 21 September 2003, ending the mission in the planet it had come to know.

1989Deployed from Shuttle AtlantisLaunch
Released in Earth orbit, then boosted on a six-year, gravity-assisted path to Jupiter.
1993First moon of an asteroidFlyby
At asteroid Ida it discovers Dactyl, the first known moon orbiting an asteroid.
1994Witness to a comet impactMilestone
Uniquely placed to watch the fragments of comet Shoemaker-Levy 9 strike Jupiter.
1995Jupiter orbit insertionArrival
Enters orbit and drops a probe — the first to sample the atmosphere of a giant planet.
2000An ocean beneath EuropaMilestone
Magnetic measurements point to a salty ocean hidden under Europa's icy crust.
2003Plunge into JupiterMission end
Steered into the planet to ensure it can never contaminate Europa.

Images

The Galileo Jupiter orbiter during pre-launch processing — NASA (public domain) · Wikimedia Commons

Moon As Seen By NIMS — NASA/JPL · NASA Image Library

Moon - Western Near Side — NASA/JPL · NASA Image Library

Gaspra Approach Sequence — NASA/JPL · NASA Image Library

Galileo Over Io Artist Concept — NASA · NASA Image Library

NIMS Observes Europa Shadow — NASA/JPL · NASA Image Library

NIMS Callisto Global Mosaic — NASA/JPL · NASA Image Library

True Color of Jupiter Great Red Spot — NASA/JPL/Cornell University · NASA Image Library

Images from open archives · credit shown per image