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
Silly Putty lint, pet hair, or ink from various surfaces. The material's unique properties have found niche use in medical and scientific applications. Physical therapists use it for rehabilitative therapy of hand injuries. A number of other brands (such as "Power Putty" and "TheraPutty") alter the material's properties, offering different levels of resistance. The material is also used as a tool to help reduce stress, and exists in various viscosities based on the user's preference. Because of its adhesive characteristics, it was used by Apollo astronauts to secure their tools in zero-gravity. Scale model building hobbyists use the putty as a masking