Saturn IV


Hyperion [hi-PEER-ee-en] is one of the smaller moons of Saturn. It has a pock-marked body and is the largest irregularly shaped satellite ever observed. Hyperion might have had a major collision which blew part of the moon away. Its eccentric orbit makes it subject to gravitational forces from Saturn which have set it tumbling out of control. The moon's rotational period is not constant and varies from one orbit to the next. Hyperion is redder than Phoebe and closely matches the color of the dark material on Iapetus. The largest crater on its surface is approximately 120 kilometers (75 miles) in diameter and 10 kilometers (6.2 miles) deep. The irregular shape of Hyperion and evidence of bombardment by meteors makes it appear to be the oldest surface in the Saturn system.

Hyperion Statistics
 Discovered byWilliam Cranch Bond 
 Date of discovery1848 
 Mass (kg)1.77e+19 
 Mass (Earth = 1)2.9618e-06 
 Radius (km)205x130x110 
 Radius (Earth = 1)3.2142e-02 
 Mean density (gm/cm^3)1.4 
 Mean distance from Saturn (km)1,481,000 
 Rotational period (days)chaotic 
 Orbital period (days)21.27661 
 Mean orbital velocity (km/sec)5.07 
 Orbital eccentricity0.1042 
 Orbital inclination (degrees)0.43 
 Escape velocity (km/sec)0.107 
 Visual geometric albedo0.3 
 Magnitude (Vo)14.19 

Animation of Hyperion

Views of Hyperion

This image of Hyperion was acquired by the Voyager 2 spacecraft on August 25, 1981. (Credit: Calvin J. Hamilton)

This image shows another view of Hyperion. It was acquired by the Voyager 2 spacecraft on August 25, 1981. (Credit: Calvin J. Hamilton)

Topographic Map of Hyperion
This is a topographic map of Hyperion. It is based upon the shape model by Phil Stooke. As with all maps, it is the cartographer's interpretation; not all features are necessarily certain given the limited data available. This interpretation stretches the data as far as possible. (Courtesy A. Tayfun Oner)


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Copyright © 1997 by Calvin J. Hamilton. All rights reserved.