On Dec. 8, 1990, NASA's Galileo spacecraft flew by Earth on its way to Jupiter. [‘On This Day in Space’ Video Series on Space.com](https://www.space.com/39251-on-this-day-in-space.html)

Galileo was the first spacecraft to study Jupiter and its moons for an extended period of time, and it actually flew by Earth twice on the way there to pick up speed. The second flyby happened 2 years later also on December 8th. Five years after its launch on Dec. 7th, 1995, Galileo arrived at Jupiter. It orbited Jupiter for eight years before NASA sent it on a crash-course into the planet's atmosphere. NASA intentionally destroyed Galileo that way so that it wouldn't run the risk of contaminated any of Jupiter's moons with bacteria from Earth.