Calypso, in astronomy, one of the named moons, or natural satellites, of Saturn. Also known as Saturn XIV (or S14), Calypso is a small, irregularly shaped (nonspherical) body measuring about 21 mi (34 km) by 13.5 mi (22 km) by 13.5 mi (22 km); it orbits Saturn at a mean distance of 183,093 mi (294,660 km), and has an orbital period of 1.8878 earth days—the rotational period is unknown but is assumed to be the same as the orbital period. Calypso was discovered in 1980 by a group led by a team at the Univ. of Arizona led by Bradford A. Smith from ground-based photographs taken with prototype cameras designed for the Hubble Space Telescope. Calypso is co-orbital with two other moons, Telesto and Tethys; that is, they orbit Saturn at the same distance. Calypso and Telesto are two of the smallest moons in the solar system.