# Hyperion

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 by ........................... William Cranch Bond
    Date of discovery ...................................... 1848

    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 eccentricity ................................. 0.1042
    Orbital inclination .................................... 0.43°

    Escape velocity (km/sec) .............................. 0.107

    Visual geometric albedo ................................. 0.3
    Magnitude (Vo) ........................................ 14.19

## Views of Hyperion

Hyperion (GIF, 8K)
This image of Hyperion was acquired by the Voyager 2 spacecraft on August 25, 1981. (Credit: Calvin J. Hamilton)

Hyperion (GIF, 7K)
This image shows another view of Hyperion. It was acquired by the Voyager 2 spacecraft on August 25, 1981. (Credit: Calvin J. Hamilton)

Saturn Titan Iapetus

##### Author: Calvin J. Hamilton.