Cassini completes last flyby of Saturn’s Dione
Scientists are getting their best look at Saturn’s moon Dione, when NASA’s Cassini spacecraft flew past the icy satellite on Monday, August 17, 2015. The spacecraft came as close as 295 miles (474 kilometers) of the moon’s surface.
The spacecraft has been orbiting Saturn since 2004, and has already conducted similar “gravity science investigations” of a handful of the ringed planet’s 62 known moons. This will be Cassini’s fifth and last close encounter with Dione during its tour of Saturn.
On this go around Cassini’s cameras and spectrometers will get high-resolution images of Dione’s north pole, in addition to mapping areas on the icy moon. The spacecraft’s Cosmic Dust Analyzer will search for dust particles emitted from Dione.
Scientists also have been eager to find out if Dione has geologic activity.
Bonnie Buratti, a member of the Cassini science team at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., said that four previous flybys of Dione have provided “hints of active geologic processes,” including evidence of transient atmosphere and ice volcanoes.
“But we’ve never found the smoking gun,” she said in a NASA statement. “The fifth flyby of Dione will be our last chance.”
Cassini’s closest-ever flyby of Dione was in Dec. 2011. The spacecraft was at a distance of 60 miles (100 kilometers) from the moon and yielded high-resolution views of the bright, wispy terrain on Dione first seen during the Voyager mission.
“This will be our last chance to see Dione up close for many years to come,” said Scott Edgington, Cassini mission deputy project scientist at JPL. “Cassini has provided insights into this icy moon’s mysteries, along with a rich data set and a host of new questions for scientists to ponder.”