Sayonara, Enceladus. On Saturday, the Cassini spacecraft will get one last closeup of Saturn’s icy moon as it flies past at a distance of 3,106 miles.
After discovering geysers spouting off the moon’s southern pole, the NASA team in charge of Cassini altered the craft’s trajectory to get as many Enceladus close-ups as possible. Now we know that the geysers are spewing water ice and simple hydrocarbons from a deep underground ocean–making Enceladus one of the top real estate areas to search for alien microbes.
After this weekend, the spacecraft will have flown by Enceladus a total of 22 times. That’s much more than Cassini scientists originally planned for. Cassini will continue to study Enceladus as it orbits Saturn until 2017, but its next closest approach to the moon will be 4 times farther than this weekend’s trajectory.
Saturday’s flyby won’t be the closest–that took place in October, when Cassini came within about 30 miles of the surface of Enceladus. Instead, the final flyby takes place at an optimal distance to map the moon’s surface, Mike Flasar from the Cassini team said in a press release.
“The distance of this flyby is in the sweet spot for us to map the heat coming from within Enceladus — not too close, and not too far away. It allows us to map a good portion of the intriguing south polar region at good resolution.”
Cassini’s discoveries at Enceladus may be winding down, but scientists are hoping to send another spacecraft there in the coming decades. Proposed missions such as the Enceladus Life Finder would swoop through the geysers with a spacecraft dedicated to finding life, or the chemicals that make life possible. Such a mission could be relatively low cost, but nothing’s officially in the works yet.