Artist’s concept of Galileo at Io with Jupiter in the background; the high-gain antenna is fully deployed. Image: NASA
Named after the Italian astronomer, physicist, engineer, philosopher, and mathematician Galileo Galilei (15 February 1564 – 8 January 1642), Galileo was an American unmanned spacecraft that studied the planet Jupiter and its moons, as well as several other Solar System bodies. Consisted of an orbiter and an entry probe, it was delivered into Earth orbit on October 18, 1989, by Space Shuttle Atlantis.
The spacecraft named after Galileo Galilei, because the four largest moons of Jupiter (Io, Europa, Ganymede, and Callisto) were first seen by the Italian astronomer in January 1610, and recognized by him as satellites of Jupiter in March 1610. These four moons are now named “Galilean moons”.
After gravitational assist flybys of Venus and Earth, Galileo arrived at Jupiter on December 7, 1995, and became the first spacecraft to orbit Jupiter.
To eliminate the possibility of contaminating local moons with terrestrial bacteria, on September 21, 2003, after 14 years in space and 8 years in the Jovian system, and after a lot of discoveries, Galileo’s mission was terminated by sending it into Jupiter’s atmosphere at a speed of over 48 kilometers per second (30 miles per second).
Galileo also observed the first extraterrestrial collision of Solar System objects that humanity has witnessed: Comet Shoemaker-Levy 9’s collision with Jupiter in July 1994.