Here’s a color-composite image of Rhea, made from raw images acquired by Cassini during a flyby on March 10, 2012. The color is derived from images taken in infrared, green and ultraviolet light.
Rhea is Saturn’s second-largest moon after Titan, but at 950 miles across (compared to 3,200!) Rhea is less than a third Titan’s diameter. Its high reflectivity is a result of its mainly being composed of water ice, which is harder than rock is on Earth at Rhea’s frigid temperatures of -300º F. Even colder than sister moons Dione and Tethys, Rhea is perhaps the most extensively cratered world in the solar system.
Credit: NASA/JPL/SSI. Edited by J. Major.