This global color mosaic of Saturn's moon Rhea was produced from images taken by NASA's Cassini spacecraft during its first 10 years exploring the Saturn system. These are the first global color maps of these moons produced from the Cassini data.
The most obvious feature on the maps is the difference in color and brightness between the two hemispheres. The darker colors on the trailing hemispheres are thought to be due to alteration by magnetospheric particles and radiation striking those surfaces. The lighter-colored leading hemisphere is coated with icy dust from Saturn's E-ring, formed from tiny particles ejected from Enceladus' south pole. These satellites are all being painted by material erupted by neighboring Enceladus.
The colors shown in these global mosaics are enhanced, or broader, relative to human vision, extending into the ultraviolet and infrared range.
Resolution on Rhea in the maps is 400 meters per pixel.
Image selection, radiometric calibration, geographic registration and photometric correction, as well as mosaic selection and assembly were performed by Paul Schenk at the Lunar and Planetary Institute. Original image planning and targeting for Saturn's icy moons were performed by Tilman Denk (Frei Universitat, Berlin) and Paul Helfenstein (Cornell University, Ithaca, New York).
Credit: NASA/JPL-Caltech/Space Science Institute/Lunar and Planetary Institute