Little is known about the tiny moon Helene other than its size (32 kilometers, or 20 miles) and its status as a Trojan moon of Dione (along with Polydeuces). All three moons share an orbit, but Helene lies 60 degrees ahead of Dione and Polydeuces lies 60 degrees behind Dione.
Calypso is a Trojan moon of Tethys orbiting Saturn 60 degrees behind Tethys. Cassini snapped the best image yet of Calypso on September 23, 2005, revealing a colorful and potato-shaped object.
Ithaca Chasma is an ancient and gigantic rift cutting across the heavily cratered surface of Tethys. Less surprising than many of the other moons of Saturn, Tethys does have its own mysteries, including bright crater floors, younger plains, and evidence of very early activity that resulted in Ithaca Chasma.
Telesto is a Trojan moon of Tethys orbiting Saturn 60 degrees ahead of Tethys. Cassini took the best ever images of this tiny moon on October 11, 2005.
Out of nowhere emerged a Saturn moon to rival Titan in mystery and activity. Here, suddenly, was an ice world not dead but alive and active, spewing out water ice and oxygen from a youthful surface, creating only the second moon atmosphere known in the Saturnian system. Because Enceladus is so small, the atmosphere is localized rather than global, and it must be replenished constantly to compensate for gas and dust loss to the space. In the process, Enceladus may just help build one of the rings of Saturn.
Near the south pole of the moon lies a roughly parallel group of fractures called the “tiger stripes.” The ice here is brand new, perhaps as young as yesterday. The tiger stripes are the warmest region on Enceladus. At 91 and 89 degrees Kelvin (or minus 296 and minus 299 degrees Fahrenheit), this certainly isn’t paradise, but compared to the surrounding temperatures that range from 74 to 81 degrees Kelvin (or minus 326 to minus 313 degrees Fahrenheit), this is downright balmy. To bring out the differences in temperatures, the pictures shown on this page are in false-color.
Just what is occurring beneath the surface of Enceladus here is not known, though the gravitational tug of war between Saturn and Titan on Enceladus may play a role. As usual, where there is present day activity and the right conditions there is speculation about lifeforms. Heat from below, liquid water or soft(er) ice around you, and oxygen above (albeit at atmospheric pressures barely above that of a vacuum) - all the ingredients for those especially hardy alien lifeforms. The search in on.
Two of the newest moons discovered by Cassini, Pallene and Methone are tiny worlds that lie between the orbits of Enceladus and Mimas. The image above may or may not show these two moons, but the camera used by Cassini to snap this image was pointing toward Pallene on September 29, 2005.
Herschel Crater covers nearly a third of the diameter of Saturn’s small moon Mimas, helping it to resemble the Death Star from Star Wars. Some of the most breathtaking images taken by Cassini of Saturn and its rings have included Mimas in the shot.
Crater upon crater upon crater indicate the surface of Mimas is ancient. Like all the moons of Saturn, Mimas is mostly made up of water ice. The sight alone of Mimas is something to behold, but many scientists thought that every moon around Saturn was going to turn out equally as dead. The Cassini-Huygens tour of the Saturnian system has proved them very wrong.
The tiny and irregular shaped Epimetheus orbits Saturn with a similar moon called Janus, both of which may have formed when a larger body was broken up during a collision earlier in its history. Because the density of Epimetheus is less than that of water, it may be porous, perhaps just a pile of rubble held weakly together by gravity.
Janus is quite similar to Epimetheus. Both moon share the same orbit and trade places with each other every four years. Janus is heavily cratered and likely very ancient.
The craters on the tiny moon Pandora are muted compared to craters on larger moons because they are filled with collapsed debris. The surface is also covered in fine icy material, perhaps as a result of Pandora’s role as a ring shepherd moon, keeping Saturn’s F ring in line.