The story of the Solar System is written upon the faces of its many worlds, such as icy Rhea (1,528 kilometers, 949 miles across) seen here in an image from Cassini. The moon's many impact craters attest to its violent beginnings and more than four billion years of subsequent history.
Most moons in the outer Solar System are icy, in contrast to the rocky inner planets and Earth's moon. When the planets and their moons first formed around our Sun, conditions were cold enough at Saturn's distance that ices could condense to form solid bodies like Rhea. Since its formation, Rhea has been battered by the leftover debris of planet building, although at a much lower rate for the past 3.8 billion years or so.
North on Rhea is up and rotated about 20 degrees to the left. This view shows principally the leading hemisphere on Rhea.
The image was taken in visible light with the narrow angle camera on May 5, 2005, from a distance of approximately 1.4 million kilometers (900,000 miles) from Rhea and at a Sun-Rhea-spacecraft, or phase, angle of 78 degrees. The image scale is 9 kilometers (6 miles) per pixel.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington, D.C. The imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.