National Aeronautics and Space Administration Logo
Follow this link to skip to the main content NASA Banner
Solar System Exploration
Return to Solar System Exploration
Facebook Twitter YouTube Facebook Twitter YouTube Flickr iTunes
Follow Us
Extended Tour

The Journey to Jupiter
Extended Tours - GEM and the Millennium Mission

Galileo's prime mission ended on December 7, 1997. With more to learn, and the spacecraft in good health, NASA approved a two-year study called "GEM" -- the Galileo Europa Mission. For fourteen more orbits, the spacecraft focused on ice, water, and fire: the icy moon Europa, which might have an ocean; Jupiter's majestic thunderstorms; and the fiery volcanoes of Io.

The Galileo Europa Mission Encounter Timeline.
The Galileo Europa Mission Encounter Timeline.

The spacecraft came so close to Europa that if there were something there the size of a school bus, Galileo would have detected it. The additional observations of Europa supported the theory that an ocean of water currently exists below the surface. NASA began considering plans for future missions to orbit Europa, and perhaps to send a lander.

Approaching Io --- Jupiter's innermost moon --- meant surviving Jupiter's intense radiation, so these encounters were saved until last. When radiation upset the spcecraft's computer, engineers worked all night to get them back on line. But Galileo came through again, and even discovered a lava fountain erupting on Io.

The Galileo Europa Mission Orbital Map.
The Galileo Europa Mission Orbital Map.

These successful flybys led to another exciting mission --- the Galileo Millennium Mission, extending into 2001. The data are collected on Io and Europa, and studies made of the effects of radiation on a spacecraft close in to Jupiter. The Cassini spacecraft, on its way to Saturn, swings by Jupiter in late 2000 and for a few weeks, both spacecraft observe the giant of our Solar System.

The Future: Jupiter Icy Moons Orbiter Next

Next: The Spacecraft Next

Mission Operations
Ice crust of Europa
Ice crust of Europa
Thunderheads on Jupiter
Thunderheads on Jupiter
Active Volcanic Plumes on Io
Active Volcanic Plumes on Io
Awards and Recognition   Solar System Exploration Roadmap   Contact Us   Site Map   Print This Page
NASA Official: Kristen Erickson
Advisory: Dr. James Green, Director of Planetary Science
Outreach Manager: Alice Wessen
Curator/Editor: Phil Davis
Science Writers: Courtney O'Connor and Bill Dunford
Producer: Greg Baerg
Webmaster: David Martin
> NASA Science Mission Directorate
> Budgets, Strategic Plans and Accountability Reports
> Equal Employment Opportunity Data
   Posted Pursuant to the No Fear Act
> Information-Dissemination Policies and Inventories
> Freedom of Information Act
> Privacy Policy & Important Notices
> Inspector General Hotline
> Office of the Inspector General
> NASA Communications Policy
> NASA Advisory Council
> Open Government at NASA
Last Updated: 9 Jul 2010