Saturn from Iapetus. Artwork of the surface of Iapetus, with Saturn and the Sun seen in the sky. Iapetus is one of the moons of Saturn. The rings of Saturn are seen in an open position here. Iapetus is the only moon of Saturn from which this view would be possible, as the other moons all orbit in the same plane as the rings, rendering them visible as only a line of light. Iapetus orbits at just over 3.5 million kilometres from Saturn, taking 79 days to complete an orbit. It is unusual in that one face is dark and the other light. Its leading face is thought to be covered in dark material picked up from space. The trailing face is covered with bright water ice.