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 15 the same time, Command Module Pilot Alfred Worden orbited the Moon, using a scientific instrument module (SIM) in the service module (SM) to study the lunar surface and environment in great detail with a panoramic camera, a gamma-ray spectrometer, a mapping camera, a laser altimeter, a mass spectrometer, and a lunar subsatellite deployed at the end of Apollo 15's stay in lunar orbit (an Apollo program first). The mission successfully accomplished its objectives, but was marred by negative publicity that accompanied disclosure of the crew carrying unauthorized postage covers to the Moon, some of which were sold by a West