On a voyage across the Galaxy to the Forbidden Planet Altair 4! Join us in our battles to save Earth! The saucer has a lenticular profile. Above there is a dome, approximately a third of the diameter of a lens. Below there is a very shallow cylinder of about the same diameter, and a somewhat smaller dome that ostensibly houses the starship's faster-than-light drive engine and central gyroscopic landing pedestal. The precise contours and proportions differ slightly between the saucer's shooting miniatures, full-size sets, and matte paintings used in the film. On landing, the C57-D's gangway and two conveyor-loading ramps swing down at an angle from the underside hull, near the edge of the lower lens shape.