Writer/director Edward Bernds first sought Sterling Hayden and then Frank Lovejoy for the lead. Producer Richard V. Heermance eventually hired Hugh Marlowe, who asked for only a quarter of the other actors' salaries. According to Bernds, Marlowe was often lazy and unprepared.
As the astronauts begin to ascend back up the mountain, they spot a column of smoke up ahead. The giant boulders in these shots are the famous Garden of the Gods formations at the Iverson Movie Ranch where the outdoor scenes were filmed. These formations were used in many films, from biblical epics like "The Robe", to westerns like "Stagecoach", "The Lone Ranger", and "Zorro", to war movies, and as fantasy/alien landscapes. The formations are feeling the encroachment of land development now, and may not last much longer.
Just four years later, one of this film's leads, Rod Taylor, would star in George Pal's The Time Machine (1960). Based on the novel by H.G. Wells, this film would be his second foray through time in his career.
This film was produced directly by Allied Artists (formerly Monogram Pictures). It was made in hopes of shedding Monogram's "poverty row" image. It was given a larger budget, shot in color and CinemaScope and ran a full reel longer than their usual 60 to 70-minute running time common to "B" pictures. Allied Artists was able to book it under percentage contracts rather than flat rates.
The film takes place in March 1957 and 2508.