N.A.S.A. co-operated fully with the film, lending the producers its facilities, including Cape Canaveral as a location.
The moon landing was simulated in the Mojave Desert.
Robert Altman finished shooting on Friday only to receive a call on the Sunday night telling him that he would not be allowed through the gates of Warner Brothers again. Jack L. Warner had looked at some of the footage and insisted on Altman's immediate firing because "that fool has actors talking at the same time," ironically, this overlapping of dialogue is an Altman trademark in his films.
In the scene where Chiz (Robert Duvall) first instructs Lee Stegler (James Caan) on the Gemini trainer, in the background there is an Apollo spacecraft, apparently under assembly, marked "CM-104." CM-104 would eventually be flown as "Gumdrop" on Apollo 9.