Apollo 8 yet ready to make its first flight. Astronaut Jim McDivitt's crew, who were training to fly the first lunar module flight in low Earth orbit, became the crew for the Apollo 9 mission, and Borman's crew were moved to the Apollo 8 mission. This left Borman's crew with two to three months' less training and preparation time than originally planned, and replaced the planned lunar module training with translunar navigation training. Apollo 8 took 68 hours (almost three days) to travel the distance to the Moon. The crew orbited the Moon ten times over the course of 20 hours, during
Apollo 1 the prime crew for a second Block I CSM flight, AS-205. NASA planned to follow this with an unmanned test flight of the LM (AS-206), then the third manned mission would be a dual flight designated AS-278 (or AS-207/208), in which AS-207 would launch the first manned Block II CSM, which would then rendezvous and dock with the LM launched unmanned on AS-208. In March, NASA was studying the possibility of flying the first Apollo mission as a joint space rendezvous with the final Project Gemini mission, Gemini 12 in November 1966. But by May, delays in making Apollo ready