Gemini 1 was the first mission in NASA's Gemini program. An uncrewed test flight of the Gemini spacecraft, its main objectives were to test the structural integrity of the new spacecraft and modified Titan II launch vehicle. It was also the first test of the new tracking and communication systems for the Gemini program and provided training for the ground support crews for the first crewed missions.

Originally scheduled for launch in December 1963, difficulties in the development of both the spacecraft and its booster caused four months of delay. Gemini 1 was launched from Launch Complex 19 at Cape Kennedy (now Canaveral), Florida on April 8, 1964. The spacecraft stayed attached to the second stage of the rocket. The mission lasted for three orbits while test data were taken, but the spacecraft stayed in space for almost 64 orbits until its orbit decayed due to atmospheric drag. The spacecraft was not intended to be recovered, and holes were drilled through its heat shield to ensure it would not survive re-entry.