Galileo was an unmanned spacecraft launched by the European Space Agency (ESA) in 1989. It was the first spacecraft to orbit Jupiter, and it provided scientists with a wealth of data about the planet and its moons. Galileo's mission lasted from 1989 to 2003, when it was deliberately crashed into Jupiter's atmosphere. During its mission, Galileo made numerous discoveries, including evidence that Jupiter's moon Europa may have a subsurface ocean of liquid water.