The San Diego Air & Space Museum's Primate Capsule is on display in the "SPACE: Our Greatest Adventure" special exhibit at the main location in Balboa Park. The Museum’s Primate Capsule is on loan from the National Air & Space Museum.

The Primate Capsule played a key role in early space flight. Initially, doctors were uncertain what would happen to humans in space. They were concerned about radiation, confined space, prolonged isolation, acceleration and deceleration forces, and especially weightlessness. Before send a human on a rocket ride, scientists decided to evaluate the effects of space travel on a chimpanzee. The chimp was selected for this mission because it is physically similar to a human and can be trained to perform basic tasks. The effect of space flight on their skill at doing these tasks could be easily studied.

The chimps were tasked for various activities during flight such as moving levers in response to flashing lights. The biopack capsule was located inside the same Mercury spacecraft in which humans would fly and connected to the same life support systems. The flight tests showed that when the chimpanzees were sent into space, they returned in good physical condition, and were able to perform tasks just as well as they did on Earth.

On January 31, 1961, Ham was the first chimpanzee sent into space aboard a Mercury Redstone rocket. He was weightless for 6.6 minutes during a 16.5 minute sub-orbital flight. A medical examination found that after the flight Ham was slightly fatigued and dehydrated, but otherwise in good health. The mission paved the way for the successful first launch of America’s first human, Alan Shepard, on May 5, 1961.

Enos was the first chimp to orbit the Earth on November 29, 1961, launched by a Mercury Atlas rocket. After splashdown, he was healthy and both he and the Mercury spacecraft had performed well. The mission concluded testing before America’s first manned orbital flight, flown by John Glenn on February 20, 1962.

The Museum’s Primate Capsule is on loan from the National Air & Space Museum.