Saturn: Moons: Hyperion

This image of Hyperion was acquired by the Voyager 2 spacecraft on August 25, 1981.

Hyperion [hi-PEER-ee-en] is the largest irregularly shaped natural satellite ever observed, even though it is one of the smaller moons of Saturn. It is likely that Hyperion may have been bombarded with meteors, which blew part of this moon away and caused its highly irregular shape. The irregular shape of Hyperion and evidence of bombardment by meteors makes it appear to be the oldest surface in the Saturn system. The largest crater on its surface is approximately 120 kilometers (75 miles) in diameter and 10 kilometers (6 miles) deep.

Hyperion is redder than Phoebe and closely matches the color of the dark material on Iapetus. Its eccentric orbit makes it subject to gravitational forces from Saturn, which causes its rotational period to vary from one orbit to the next.