8 grudnia 1990 roku sonda wykonując asystę grawitacyjną przeleciała w odległości 965,6 km od Ziemi.
Galileo Earth FlybyDec. 8, 1990

(...) NASA's Galileo spacecraft will pass within 600 miles of Earth at 12:35 p.m. PST Saturday, December 8, 1990, as it continues to work its way out to Jupiter.
During this flyby, Galileo will pick up some of the energy necessary to reach the giant planet in 1995. It will increase its speed in solar orbit by about 11,600 mph.
One more Earth gravity assist, in 1992, will pump up the flight path the rest of the way to Jupiter, for a 1995 encounter. An earlier gravity assist, at the planet Venus in February 1990, set the conditions for today's Earth flyby. (...)
https://www.jpl.nasa.gov/news/galileo-earth-flyby