Galileo didn't have enough fuel to fly directly to Jupiter, but the spacecraft could borrow
enough energy from Venus and Earth to make the long journey. Mission planners designed a
flight path nicknamed "VEEGA" -- Venus-Earth-Earth Gravity Assist. Galileo would slingshot once
by Venus, and twice by Earth, gathering enough momentum to reach distant Jupiter.
First stop: Venus. The Galileo team tried out the spacecraft's instruments and study of the
thick, toxic clouds that cloak our sister planet. Flying by our home planet twice, we saw the
Earth and Moon together -- as someone from another world might view us.
After the first Earth flyby, Galileo's umbrella-shaped high-gain antenna did not open as
planned. But the Galileo team worked hard to reprogram the spacecraft to send back data
through a smaller antenna. Engineers at NASA's Deep Space Network upgraded their antennas as
well. The result allowed scientists to capture almost all the information originally planned.
On Galileo's first trip through the asteroid belt, the spacecraft took detailed images of an
asteroid named Gaspra - the first close approach to an asteroid. On a second pass through the
asteroid belt, Galileo discovered a miniature moon orbiting asteroid Ida. This tiny body was
In 1994, Galileo was perfectly positioned to watch the fragments of comet Shoemaker-Levy 9
crash into Jupiter. The spacecraft made the only direct observations of the impact. Earth-based
telescopes had to wait to see the impact sites as they rotated into view.
- Venus Flyby: 2/10/1990 (16,000 km distance)
- Earth-1 Flyby: 10/8/1990 (960 km distance)
- Gaspra Flyby: 10/29/1991 (1600 km distance)
- Earth-2 Flyby: 12/8/1992 (305 km distance)
- Ida Flyby:
8/28/1993 (2400 km distance)
Discovery: Dactyl, first known moon of an asteroid
- Comet S/L-9 Jupiter Impact: July 16-22, 1994
Next: Arrival at Jupiter and the Probe Mission