Enceladus' surface. Coloured Cassini spacecraft image of the surface of Enceladus, one of Saturn's moons. The crater at bottom with a central dome has a diameter of 20 kilometres. The large number of impact craters in this region suggest that this terrain is amongst the oldest on the moon. At upper right are twisted ridges and troughs. Enceladus is composed of water ice, silicates and iron. Its surface features suggest the presence of a subsurface ocean, although this has not been confirmed. The Cassini-Huygens spacecraft was launched in 1997 to investigate Saturn, its rings and its moons. This image was taken at a distance of 29,000 kilometres on 9 March 2005.