Mimas is the innermost of Saturn's larger moons, orbiting outside the rings of its parent planet. A nearly cataclysmic impact produced the large crater Herschel that gives Mimas its distinctive "Death Star" or "eyeball" appearance. If the impact had been slightly larger, Mimas may have broken apart. Herschel is 140 km (90 mi) across and 10 km (6 mi) deep. It is one-third the diameter of Mimas and one of the largest craters--with respect to planetary diameter--in the solar system.