HYPERION

one of the smaller satellites of Saturn, discovered in 1848 independently by the astronomers William Bond and George Bond of the United States and William Lassell of England. Hyperion orbits Saturn once every 21.3 days at a distance of 1,482,000 km (918,840 miles), between the orbits of the major satellites Titan and Iapetus. Its orbit is unusual in that it is somewhat eccentric (e = 0.104) yet uninclined (i = 0.4). Hyperion is an irregularly shaped body that measures 410 260 220 km (254 161 136 miles). It has a moderately high reflectance of 30 percent, which is consistent with the presence of some water frost on its surface.