The standard Hasselblad 500C was extensively used by NASA during the Project Mercury program in 1962-3, and continued through to Project Gemini. During Gemini 10 in 1966, astronaut Michael Collins accidentally let slip his camera during a space-walk, and it drifted into space. For the Apollo moon-landing program, the motorized 500 EL was adopted, with extensive modifications to the electrics and lubrication to allow its use in a high-oxygen environment within the spacecraft, and in the extremely variable temperatures and near-vacuum conditions outside.
In order to accurately measure objects photographed on the moon, a clear plate with a pattern of crosshairs was inserted just in front of the film plane. Neil Armstrong had the camera firmly strapped to his chest and had to use guesswork to frame the iconic images of Buzz Aldrin. A total of 12 Hasselblads were left on the moon’s surface during the Apollo program – only the exposed film and magazines making the return trip.