Cassini gears up for final look at Saturn’s icy moons

NASA’s Cassini mission is gearing up for the home stretch, as the Saturn-orbiting spacecraft will get its final looks at the icy moons of Enceladus and Dione over the next six months, starting in a couple of weeks with the latter, according to report published late last week.

Cassini will be conducting three additional flybys of Enceladus, an extremely bright object that reflects nearly all of the sunlight that strikes it and which has already been analyzed by the probe on multiple occasions, and one of Dione, which Space.com said will take place on August 17.

Why so much interest in these icy moons? Discovery News explains that NASA believes they may represent some of the best chances of finding life on other planets, as there might be liquid oceans filled with microbes lurking beneath their frozen surfaces. Gravitational interactions with Saturn may warm them enough to allow these tiny living creatures to survive, they said.

Searching for evidence of plumes on Dione

First up will be Dione, where Cassini will conduct gravitational measurements to learn more about the icy shell and interior of this moon. Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory, told Discovery News that they believe Dione may have the same type of eruptions as Enceladus, and they hope to find out for sure this month.

“We haven’t found the equivalent of a smoking gun,” Spilker said. The lack of evidence may be due to the larger size of the moon. A bigger moon means more gravity, which could be pulling down the plumes and making them more difficult to see. In addition to this month’s flyby, far-off observations set for 2017 could also be used to find evidence of these plumes.

The spacecraft will also be looking at the plumes of Enceladus, which were first discovered by the probe’s magnetometer instrument, in the best detail thus far. The final three flybys of the popular Cassini target are scheduled to begin on October 14, with a view of the north pole. A “plunge” into a known plume location is set to follow two weeks later, and the probe will travel to the moon’s south pole to study the thermal environment there in December.

Cassini’s mission is expected to end in 2017, when it will use the gravity of Saturn’s moon Titan to “hop” into a spot in the inner part of the planet’s rings. Once it arrives, it will remain there for 22 orbital cycles before plummeting into the atmosphere on September 15.

Image: The plumes of Enceladus as seen by Cassini in 2009. (Image credit: NASA)