Updated: January 22, 2024

Forbidden Planet production:

In the film's screenplay the starship carries no name, only the designation "United Planets Cruiser C-57D".

The saucer has a lenticular profile. Above there is a dome, approximately a third of the diameter of the 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 saucer's gangway and two conveyor-loading ramps swing down at an angle from the underside hull, near the edge of the lower lens shape.

The film's blueprints for the command deck show it to have a central circular "navigation center" with a transparent globe centered on a small model of the starship. Around this central space are a number of wedge-shaped rooms, including:

A room with a curved table, chairs, and a space for books ( presumably a galley and recreation room ). A room with the "communications center", a chart table and the "main viewscope". A room with 16 bunk beds, with a pit and crane between it and the central area. A room with 9 "decelerator platforms". The film shows the crew standing on these low, cylindrical platforms, enveloped within an opaque blue glow while the saucer decelerates from hyperdrive, but does not show whether these low platforms must also be used during the transition to faster-than-light speed.

On the starship's mezzanine level there is an instrument station and other rooms that aren't seen.

The studio created a stage set of the interior command and mezzanine decks and a 60-foot ( 18 m ) semicircular mock-up of the landed saucer's lower half ( with the deployed central landing pedestal, gangway, and conveyor ramps ). The sets suggest that the starship is somewhere between 100 feet ( 30 m ) and 175 feet ( 53 m ) feet in diameter.

Three saucer miniatures were used, of 22 inches ( 56 cm ), 44 inches ( 110 cm ), and 82 inches ( 210 cm ) or 88 inches ( 220 cm ) in diameter, and costing an estimated total of $20,000. The largest miniature, constructed of wood, steel, and fiberglass, which contained the internal motors for the gangway, conveyor ramps, central landing pedestal, and glowing red-neon light engine, weighed 300 pounds ( 140 kg ).

In 1970 MGM sold off these miniatures as part of the large MGM studio auction, but there was no record kept of who bought the largest of the three. A North Carolina man, who originally bought it for $800.00, stored it in his garage but hadn't realized its market value until 2008; he finally put the saucer up for auction that year, and it sold for $78,000.