Cassini to Buzz Saturn's Moon Dione One Last Time

As we rapidly approach Cassini’s thrilling final stages of its mission, the list of “final” events is gradually shrinking. Next on the NASA spacecraft’s final list is Dione — coming within 295 miles (474 kilometers) of the Saturn moon’s surface on Aug. 17 (Monday).

This close approach will be used by mission scientists to carry out a high-resolution imaging campaign of the moon’s cratered surface and gain an intimate measure of its gravitational field, revealing some further detail of its interior.

Also, scientists will be gaining high-resolution spectrometry data of its surface and infrared instruments will map out regions on the 700 mile-wide moon that are known to have “unusual thermal anomalies,” according to a NASA news release.

Although Monday’s flyby will be close, it’s not Cassini’s closest pass of Dione. In 2011, the mission came within 60 miles (100 kilometers) from the surface, revealing some surprising evidence of geological activity and, possibly, evidence of cryo-volcanoes. Now mission scientists are excited for the mission’s fifth pass, as it’s their last opportunity to unravel Dione’s mysteries.

“Dione has been an enigma, giving hints of active geologic processes, including a transient atmosphere and evidence of ice volcanoes. But we’ve never found the smoking gun. The fifth flyby of Dione will be our last chance,” said Cassini science team member Bonnie Buratti, at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

Since arriving in Saturn orbit in 2004, Cassini has only been able to gain such a close view of a handful of Saturn’s 62 known moons, so every flyby of the Saturnian satellites it can make close encounters with is of extreme scientific importance.

From Discovery News