Cassini-Huygens

Cassini-Huygens remains the definitive Saturn mission, transforming our understanding of the ringed planet over 13 years (2004-2017). It discovered geysers of water ice erupting from Enceladus, making that moon a prime candidate for extraterrestrial life, and landed the Huygens probe on Titan—the first landing in the outer solar system—revealing methane lakes and rain cycles. The mission captured 453,000 images and its Grand Finale plunge in 2017 provided direct measurements of Saturn's atmosphere. Cassini outperforms #8 (International Space Station) in scientific discovery per dollar, yielding breakthroughs at a fraction of the ISS's $150 billion cost.