Rhea, at 1,528 kilometres (949 mi) across, is the second-largest moon of Saturn and the ninth largest moon in the Solar System. It was discovered in 1672 by Giovanni Domenico Cassini, who named it after the Titan Rhea of Greek mythology, "mother of the gods".
The giant Tirawa impact basin is seen above and to the right of center. Tirawa, and another basin to its southwest, are both covered in impact craters, indicating they are quite ancient.Photo credit: Cassini orbiter