Voyager 2 image of Hyperion.
HYPERION - MOON OF SATURN
Hyperion was a Titan, the son of Uranus and Gaia. He had three children : Helios, Selene, and Eos.
Hyperion was discovered independently by Bond and Lassell in 1848 on the very same day.
Orbit
Hyperion orbits 1,481,100 kilometres from Saturn, following a slightly elliptical path about the planet, and taking just over 21 days to complete one orbit. Voyager and ground-based observations have shown that Hyperion rotates chaotically. Its continuation in an unpredictable orbit may be the combined effect of its irregular shape and its 3:4 orbital resonance with Titan. When Titan, which is quite massive, is aligned with Hyperion every fourth orbit, it exerts a gravitational pull. The effect upon Hyperion varies with Hyperion's orientation. It is possible that the collision which sent Hyperion tumbling about Saturn occurred relatively recently; otherwise it may have stabilised.
The orbits of Titan, Hyperion, Iapetus, and Phoebe.
Physical properties
Hyperion's average diameter is 286 kilometres but it is very irregular, measuring 410 x 260 x 220 kilometres. Bodies of this size are usually spherical. It is possible that Hyperion is a fragment left-over from a collision with a larger object which no longer exists.
Interior
Hyperion has quite a low density (1440 kg m-3 ), about the same as Dione, but higher than most of Saturn's icy moons. Its low density indicates that it comprises mostly water ice and contains only a small amount of rock.
Magnetic field
No magnetic field has been detected.
Atmosphere
No atmosphere has been detected.
Surface
The surface is quite dark (albedo 0.3), distinguishing it from most of Saturn's other satellites. The more reflective satellites are icy, whilst Hyperion and Phoebe are probably mantled by a layer of rock dust. Voyager images show a rough and pitted surface and reveal its reddish hue. A curved scarp, 120 kilometres long and about 10 kilometres high, runs across the surface of Hyperion and is probably part of an impact crater. It was very likely formed when Hyperion was still part of a larger body. Most craters are smaller, about 10 kilometres, though there are a few 40 to 50 kilometres craters. Hyperion has a mixture of angular and rounded edges
Hyperion has a curved scarp, 10 kilometres high, seen here catching the sunlight.	Three views of Hyperion acquired as Voyager 2 flew by at a distance of 1.2 million, 700,000, and 500,000 kilometres.