Originally, writer/director Duncan Jones wanted to cast Sam Rockwell in what eventually became Mute (2018). However, Jones and Rockwell could never come to an agreement on which part he should play, and scheduling conflicts made an immediate collaboration on that film difficult. Because they got on so well and Jones wanted to work with Rockwell so much, he asked him what would interest him; when Rockwell named the blue collar characters from Outland... Loin de la Terre (1981), Silent Running (1972) and Alien, le 8ème passager (1979) as the sort of role that he wanted to try, Jones wrote this film for him. Rockwell would later make an uncredited cameo in Mute as his Sam Bell character from Moon.
Kevin Spacey read the script and agreed to voice GERTY, but only when the film was finished and if he liked it. Having loved it, he recorded his lines in half a day.
The outdoor moon scenes were shot using practical effects (miniature model photography), polished in post-production with digital techniques where they looked unconvincing (director Duncan Jones called it 'a hybrid look'). Shooting them took place over 8 days according to Cinefex magazine July 2009.
As part of the presentation of the movie at NASA, the director was asked about the sturdy, bunker-like design for the base. The director explained that he thought that astronauts would build the base using material dug out of the moon itself, instead of bringing a habitat with them and placing it on the surface. As it happened, one of the other audience members was working on "mooncrete", which as she explained to the director is a concrete-like material that could be made out of rocky "regolith" on the lunar surface.
Producer Stuart Fenegan performed the stunt when Sam hits his head, because the stuntman was not present on that day and, as Fenegan put it in the DVD commentary, he was the only person who would not have sued the production in case of the stunt going wrong. Fenegan was quite proud of how his shot turned out.
Duncan Jones: The shadow of one of the rescuers coming through the door at the end (as confirmed by DVD commentary). Jones is also one of the radio voices at the end.