The history of Ida is constrained its membership in the Koronis
family, its satellite Dactyl, the record of impacts left on its
surface, and other dynamical, morphological, and spectral properties.
Models of crater production and comparably effective erasure processes,
combined with the current size-frequency distribution of craters, suggest
that the age of the surface is either 50 Myr or > 1 Byr. The youngest
age may inconsistent with the degraded appearance of many craters,
while the older age conflicts with the collisional life expectancy
of Dactyl. Consideration of Dactyl's evolution may resolve this issue as
well as shed light on the formation of Dactyl, the density of Ida,
and possible source regions for Ida and Dactyl within the Koronis
parent body