NASA’s Galileo spacecraft was launched on October 18, 1989, with the mission of studying Jupiter and its moons. It orbited Jupiter for almost eight years and made close passes by all its major moons. By doing so, it became the first spacecraft to orbit an outer planet in our solar system. Galileo also studied two asteroids, Gaspra and Ida, and discovered the first moon orbiting an asteroid (Dactyl orbiting Ida).
