Calypso is a Trojan (trailing moon) of the larger moon Tethys. Calypso trails Tethys in its orbit by 60 degrees. (Telesto is the other Tethys Trojan, orbiting Saturn 60 degrees ahead of Tethys.)
Calypso is 22 km (14 miles) across. Like many other small Saturnian moons and small asteroids, Calypso is irregularly shaped by overlapping large craters. This moon appears to also have loose surface material capable of smoothing the appearance of craters.
Calypso was discovered by D. Pascu, P.K. Seidelmann, W. Baum, and D. Currie in March 1980 using a ground-based telescope.
How Calypso Got its Name:
Moons of Saturn were originally named for Greco-Roman Titans and descendants of the Titans. But as many new moons were discovered scientists began selecting names from more mythologies, including Gallic, Inuit and Norse stories.
Calypso (kuh-LIP-soh) was a nymph whose name means "I hide." A daughter of the Titans, Oceanus and Tethys, she lived alone on her island until she fell in love with the explorer Odysseus (called Ulysses by the Romans; his name means "one who suffers"). Calypso helped Odysseus find his way home after his long voyage and dangerous adventures.