 Phobos is heavily cratered.The most prominent of these is the crater, Stickney, (named after Asaph Hall's wife, Angeline Stickney Hall, Stickney being her maiden name) a large impact crater some in diameter, taking up a substantial proportion of the moon's surface area.As with Mimas's crater Herschel, the impact that created Stickney must have nearly shattered Phobos.