This went into production as RKO was preparing to shut down. It was believed to have had a much larger budget which was later cut. This greatly affected the quality of the special effects.

Among the last-minute cost-cutting measures inflicted upon this film was the elimination of all scenes taking place on the moon.

This was one of the last films produced for RKO. By the time it was completed, RKO had ceased production and distribution. It was released through Warner Brothers.

Some of the music is actually the "electronic tonalities" created by Louis Barron and Bebe Barron for Forbidden Planet (1956).

Although shot in academy 1.37:1 aspect ratio (for later television airing) the theatrical--or intended (by the studio, producer, director and/or cinematographer)--aspect ratio of this film is 1.85:1 widescreen. Most modern 16x9 (1.78:1) televisions have a "zoom to width" picture option, essentially allowing the viewer to see the film as the director and cinematographer originally planned. It is easy to spot films shot this way since all the titles and credits will still fit when properly cropped (they stay in the "middle" of the frame vertically), and there is an unusual amount of "headroom" above the actors in medium and close-up shots when viewed uncropped. Quite often "mistakes"--like seeing equipment in the top or bottom of the uncropped frame--would never have been seen by a theater audience.

Melville Cooper's last movie.