Dione

Dione (Saturn IV) was discovered by Cassini in 1684. Space probes have revealed traces of ice on the surface of this satellite which, like its neighbours, is covered with craters and has one face "in the forward direction" which is very different from the other.

Like Tethys, Dione is not alone on its orbit, but is accompanied by the satellite Helene, in the lead by 60° on a common orbit.