 Ida is one of the most densely cratered bodies yet explored in the Solar System , and impacts have been the primary process shaping its surface . Cratering has reached the saturation point , meaning that new impacts erase evidence of old ones , leaving the total crater count roughly the same . It is covered with craters of all sizes and stages of degradation , and ranging in age from fresh to as old as Ida itself . The oldest may have been formed during the breakup of the Koronis family parent body . The largest crater , Lascaux , is almost 12 km ( 7 @.@ 5 mi ) across . Region 2 contains nearly all of the craters larger than 6 km ( 3 @.@ 7 mi ) in diameter , but Region 1 has no large craters at all . Some craters are arranged in chains . 
