When the first Agena Target Vehicle exploded during launch, the Gemini VI mission was left without a rendezvous target. It was soon determined however that the following Gemini VII spacecraft would make a good substitute. Gemini VII launched first. Part of its mission was to spend enough time in space to simulate a journey to the moon and back. On December 15, 1965 the renamed Gemini VI-A launched. After achieving orbit the spacecraft was able to locate and maneuver to rendezvous with Gemini VII. The two craft maintained station for 5 hours coming as close as 30 cm. This was the first time two spacecraft had flown so close together in space and confirmed the feasibility of the docking maneuvers that would be required for a journey to the moon.