When Gemini 12 was being planned, one of the possibilities raised was the potential for the flight to be run in conjunction with the first Apollo mission, which had been tentatively scheduled for the last quarter of 1966. By May 1966, delays in making Apollo ready for flight just by itself, and the extra time needed to incorporate compatibility with the Gemini, made that impractical. This became moot when slippage in readiness of the Apollo spacecraft caused the last-quarter 1966 target date to be missed, and the Apollo mission was rescheduled for February 21, 1967.