Gemini 5 was launched on August 21, 1965, with astronauts Gordon Cooper and Pete Conrad on board. During their 8 days in orbit, the crew circled the Earth 120 times. The mission was important for its medical experiments in the effects of long-term weightlessness. Gemini 5 set a new human spaceflight endurance record, exceeding the Soviet record of 5 days. Gemini 5 was also the first U.S. space mission to carry fuel cells, but their weak performance almost forced an early termination of the flight. Much of the flight had to be carried out in a powered-down configuration, resulting in the cancellation of a planned rendezvous test with an ejected radar pod. Later in the flight, Cooper and Conrad did rendezvous with a simulated target.

In 1967 NASA transferred Gemini 5 to the Smithsonian Institution, but it has been on exhibit in Houston since before that time.