"Rhea is a so-called icy moon because it is composed primarily of water-ice. Rhea lacks any significant atmosphere, however scientists expect that Rhea has enough mass to hold a tenuous, or very thin atmosphere. Evidence of this has not been observed yet.

"Like most other icy moons of Saturn, the surface of Rhea is heavily cratered. Image number two should also show a portion of Rhea's "whispy terrain" near the trailing hemisphere. This geologic feature is known to be a series of cracks and fractures due to past tectonic activity."