Apollo 11 the CMP on the Apollo 8 crew, began experiencing trouble with his legs. Doctors diagnosed the problem as a bony growth between his fifth and sixth vertebrae, requiring surgery. Lovell took his place on the Apollo 8 crew, and, when Collins recovered, he joined Armstrong's crew as CMP. In the meantime, Fred Haise filled in as backup LMP, and Aldrin as backup CMP for Apollo 8. Apollo 11 was the second all-veteran crew on an American mission, the first being that of Apollo 10. The next was STS-26 in 1988. The backup crew consisted of Lovell as Commander, William Anders
Apollo 7 Command Module Pilot and Cunningham was Lunar Module Pilot. Their mission was Apollo's 'C' mission, an 11-day Earth-orbital test flight to check out the redesigned Block II CSM with a crew on board. It was the first time a Saturn IB vehicle put a crew into space; Apollo 7 was the first three-person American space mission, and the first to include a live TV broadcast from an American spacecraft. It was launched on October 11, 1968, from what was then known as Cape Kennedy Air Force Station, Florida. Despite tension between the crew and ground controllers, the mission was a