243 Ida

243 Ida is an asteroid of the Koronis family in the main asteroid belt, discovered on 29 September 1884 by the Austrian astronomer Johann Palisa at Vienna Observatory and named for a nymph of Greek mythology. Later telescopic study classified it as an S-type asteroid, the most common type in the inner asteroid belt, and on 28 August 1993 it was visited by NASA's uncrewed Galileo spacecraft on its way to Jupiter, becoming only the second asteroid ever visited by a spacecraft and the first discovered to have a natural satellite of its own, the small moon Dactyl.