Tethys (pronounced /ˈtiːθɨs/, /ˈtɛθɨs/, or as Greek Τηθύς) is a moon of Saturn that was discovered by Giovanni Domenico Cassini in 1684.
Space Shuttle Tethys (disambiguation) Tethys (or Saturn III) is a mid-sized moon of Saturn about km (mi) across. It was discovered by G. D. Cassini in 1684 and is named after the titan Tethys of Greek mythology. Tethys has been approached by several space probes including Pioneer 11 (1979), Voyager 1 (1980), Voyager 2 (1981), and multiple times by Cassini since 2004.