sentences:  More-recent studies, however, suggest that all of Saturn's moons inward of Titan are no more than 100 million years old; thus, Iapetus is unlikely to have formed in the same series of collisions as Rhea and all the other moons inward of Titan, and—along with Titan—may be a primordial satellite.Iapetus has been imaged multiple times from moderate distances by the "Cassini" orbiter.However, its great distance from Saturn makes close observation difficult.