Home Two views from NASA’s Galileo mission of Jupiter’s moon Europa. The left image shows the approximate natural color appearance of Europa. The right image is a false-color composite of violet, green and infrared images to enhance color differences in the predominantly water-ice crust of Europa. (NASA/JPL/DLR) Two views from NASA's Galileo mission of Jupiter's moon Europa. The left image shows the approximate natural color appearance of Europa. The right image is a false-color composite of violet, green and infrared images to enhance color differences in the predominantly water-ice crust of Europa. (NASA/JPL/DLR)

Two views from NASA’s Galileo mission of Jupiter’s moon Europa. The left image shows the approximate natural color appearance of Europa. The right image is a false-color composite of violet, green and infrared images to enhance color differences in the predominantly water-ice crust of Europa. (NASA/JPL/DLR)

This is a mosaic of images showing cracks in Saturn’s moon Enceladus taken by the Cassini spacecraft during its close flyby on March 9 and July 14, 2005. (NASA/JPL/Space Science Institute)

$This is a close-up view of the fractures on Enceladus taken by Cassini during its flyby Nov. 21, 2009. The area, about 504 kilometers (313 miles) across, focuses on Baghdad Sulcus, a fracture in the south polar region. (NASA/JPL/SSI)$