Gemini 5

Gemini 5 was a 1965 crewed spaceflight in NASA's Project Gemini. It was the third crewed mission of the program, and the fifth human spaceflight launched by the United States. The mission, crewed by astronauts Gordon Cooper and Pete Conrad, lasted for nearly eight days (7 days, 22 hours, 55 minutes), setting a new space endurance record at the time and demonstrating the feasibility of longer-duration missions necessary for eventual lunar voyages.

The primary objectives of Gemini 5 included demonstrating crewed spaceflight for a duration sufficient to support a lunar mission, evaluating the performance of a newly developed fuel cell power system, demonstrating and evaluating guidance and navigation techniques for future rendezvous, and conducting several scientific and technological experiments.

A major experiment involved the deployment of a Radar Evaluation Pod (REP) which was intended to test rendezvous radar capabilities. However, due to a fuel cell malfunction, the REP deployment was modified and the rendezvous exercise was simulated using onboard computers. Other experiments included photography of Earth, meteorological observations, and tests of medical monitoring equipment.

The mission encountered several challenges, including the aforementioned fuel cell anomaly that reduced power availability and forced a shortening of the planned mission duration. Despite these issues, Gemini 5 successfully achieved its primary objective of demonstrating long-duration spaceflight and contributed significantly to the development of technologies and procedures crucial for the Apollo program. The spacecraft landed in the Atlantic Ocean and was recovered by the USS Lake Champlain.