Saturn has 31 known moons – more than any other planet except Jupiter. One of them, Titan, is planet-sized, but the others are much smaller. Most of the moons are icy, and covered with many round craters of different sizes. These have been dug by comets and rocky meteorites crashing into them.
Tethys has a huge crater with a peak in the centre, making it look like the 'Death Star' in the Star Wars movies. Mimas also has a giant crater, hundreds of kilometres across.
Although their surfaces are extremely cold, some of the moons seem to be warm inside. Parts of the moon Enceladus are smooth, and seem to have been covered with material thrown out of ice volcanoes.
Another strange world is Iapetus. It has one face that is very bright, but the opposite side is blacker than coal. The smaller satellites orbit very close to the rings or far away from the planet. The most distant moons behave like drunken drivers going the wrong way down a one way street. They are thought to have come too close to Saturn and been captured by its powerful gravity.
Some of the smaller moons orbit inside the rings. They act as 'shepherds', keeping the ring particles in place. Two of them even swap orbits as one overtakes the other.