Saturn's moon Hyperion. Cassini spacecraft image of Saturn's moon Hyperion. This irregular shaped moon has the dimensions 328 by 260 by 214 kilometres. It is thought to consist of water ice with few impurities. It is also thought that due to its low density much of its interior is empty. The surface of Hyperion is covered in large impact craters. The Cassini-Huygens spacecraft was launched in 1997 to investigate Saturn, its rings and its moons. This image was taken in June 2005.