• satellite of Saturn discovered by Bond in 1848. It orbits Saturn in a 21 day, 1.48 million km orbit of high eccentricity (0.104), and appears to have an icy surface. The Voyager 2 encounter with Saturn reveals Hyperion as a distorted sphere which measures about 410 by 210km and which has been severely deformed, possibly by impact. It turns on its short axis, parallel to Saturn, every 13 days, with the long axis pointing towards Saturn, a pattern which may be unstable over long periods and may be caused by a gravitational interaction between Hyperion, Saturn and Titan.