 Ida has a moon named Dactyl, official designation (243) Ida I Dactyl (/ ˈdæktᵻl / DAK-til). It was discovered in images taken by the Galileo spacecraft during its flyby in 1993. These images provided the first direct confirmation of an asteroid moon. At the time, it was separated from Ida by a distance of 90 kilometres (56 mi), moving in a prograde orbit. Dactyl is heavily cratered, like Ida, and consists of similar materials. Its origin is uncertain, but evidence from the flyby suggests that it originated as a fragment of the Koronis parent body.
