Primate Capsule, Mercury

Prior to the flights of astronauts in Project Mercury, the first U.S. human spaceflight program, chimpanzees were used to better understand the effects of acceleration and weightlessness. Instead of a spacesuit, these chimps had a pressurized capsule that allowed them to breathe even in case of a failure of spacecraft cabin pressure. The chimp was strapped into a retaining harness inside the capsule and had to operate a system of levers and lights to test its reactions to flight. It was rewarded with banana pellets or a drink of water, or punished with mild electrical shocks, for taking the right or wrong actions.

Chimps were launched into space twice: "Ham" on Mercury-Redstone 2 in January 1961, and "Enos" on Mercury-Atlas 5 in November 1961. In 1967 the NASA Manned Spacecraft Center in Houston transferred this capsule to the Smithsonian. It is unknown whether it was used on a mission.