“Enceladus was so exciting that, instead of just three close flybys planned for our four-year primary mission, we added 20 more, including seven that went right through the geysers at the south pole,” said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, California. By following the trail of scientific breadcrumbs, Cassini eventually found that Enceladus harbors a global ocean of salty water under its icy crust, possibly with hydrothermal vents on its seafloor.