Cassini-Huygens

A joint NASA/ESA mission that orbited Saturn for 13 years (2004-2017), Cassini transformed our understanding of the ringed planet. It discovered geysers of water ice erupting from Enceladus (making it a prime candidate for extraterrestrial life), landed the Huygens probe on Titan — the first landing in the outer solar system — and revealed Titan's methane lakes and rain cycles. Cassini's "Grand Finale" plunge into Saturn's atmosphere in 2017 was one of the most poetic endings in exploration history.