Although SAG minimum was $175 per week, Robert Clarke's pay was $175 for the entire film. His final check was $210 with overtime.

Filmed in six days.

To stretch his meager budget, director Edgar G. Ulmer was able to use sets from the big-budget epic Joan of Arc (1948).

According to producer Jack Pollexfen, the original budget was set at $38,000 and it was ultimately brought in by director Edgar G. Ulmer at $41,000.

According to producer Jack Pollexfen, director Edgar G. Ulmer did rewrites, designed the moon and spaceship and glass paintings to expedite the production and cut down on expenses.

Margaret Field and Robert Clarke had recently worked together on A Modern Marriage (1950) and were chosen over 100 other applicants.

Film debut of Harold Gould (uncredited, as "Frightened Villager").

According to Robert Clarke, Pat Goldin, who played the spaceman, complained about billing, short pay and the heat of the costume . . . to no avail. According to producer Jack Pollexfen, Goldin did a slow-motion vaudeville act.

Steven Spielberg created the musical communication between humans and aliens at the end of Close Encounters of the Third Kind (1977) after this movie.