Cassini first detected active water-rich geysers erupting from Saturn’s moon Enceladus during a close flyby in 2005.
NASA, ESA and the Italian Space Agency launched the Cassini-Huygens mission in 1997. Cassini entered Saturn orbit in 2004 and began studying the planet, its rings and its moons. On 14 July 2005, instruments observed unusual icy jets near Enceladus’s south pole.
Later flybys showed that the plumes contained water vapor, ice particles and organic compounds. Cassini’s gravity measurements and observations of the plume supported the existence of a global subsurface ocean beneath the moon’s icy crust.
The discovery made Enceladus one of the Solar System’s most important targets in the search for potentially habitable environments. Cassini ended its mission by entering Saturn’s atmosphere on 15 September 2017.