Tethys' icy surface. Image: NASA/JPL/SSI
Wispy Dione steps in front of Tethys (February 10, 2006). Image: NASA/JPL/Space Science Institute
Dione's surface. Image: NASA/JPL/SSI
NASA’s Cassini Spacecraft has taken pictures of Tethys and Dione. Both moons were discovered in 1684 by Giovanni Domenico Cassini. 327 years later, we know that both moons have icy surfaces composed almost entirely of water-ice.
