The $3.2 billion Cassini-Huygens mission — a joint effort of NASA, the European Space Agency and the Italian Space Agency — has made a number of mind-blowing discoveries during its time in the Saturn system.
For example, Cassini spotted liquid-hydrocarbon seas on Titan, making the moon the only place beyond Earth known to harbor bodies of stable liquid on its surface. (And the mission's piggyback lander, called Huygens, touched down on Titan in January 2005, becoming the first probe ever to land on a body in the outer solar system.)
Cassini also discovered Enceladus' amazing water plumes, which in turn helped reveal that the satellite hosts an ocean of liquid water beneath its icy shell. And the probe has imaged Saturn's diverse family of moons in detail that was not possible before.
In addition, the mission has studied the dynamics of Saturn's rings extensively, revealing the intricate relationships among planet, rings and moons. Saturn's unique environment has acted like a natural laboratory, demonstrating how moons are formed and destroyed — findings that can be scaled up to better understand how planets formed around the sun and, perhaps, around other stars, scientists have said. In short, the data gathered by the spacecraft will keep researchers busy for decades to come, scientists said.