Cassini Returns Images of Battered Saturn Moon

In its last close flyby of Saturn’s moon Rhea, NASA’s Cassini spacecraft captures new images of the battered, icy moon.

In its last close flyby of Saturn’s moon Rhea, NASA’s Cassini spacecraft captured new images of the battered, icy moon. They show an ancient, cratered surface bearing the scars of collisions with many space rocks. Scientists are still trying to understand some of the curious features they see in these Rhea images, including a curving, narrow fracture (above). This feature looks remarkably recent, cutting most of the craters it crosses, with only a few small craters superimposed.

Cassini flew by Rhea at an altitude of 997 kilometers on March 9. This flyby was designed primarily for the radio science subsystem to measure Rhea’s gravity field. During closest approach, while the radio science subsystem was measuring gravity, the imaging team captured 12 images of Rhea’s rough and icy surface. Outbound from Rhea, Cassini’s cameras captured a set of global images from a distance of about 269,000 kilometers.

Data from Cassini’s cosmic dust analyzer were also collected to try to detect any dusty debris flying off the surface from tiny meteoroid bombardments. These data will help scientists understand the rate at which “foreign” objects are raining into the Saturn system.

This was the mission’s fourth close encounter with Rhea. The spacecraft will pass the moon again in a few years, but at a much greater distance.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency.