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
Putty used, as these emit very little odour, are more easily cleaned up and are compatible with water-based and latex sealers. Plumber's putty is waterproof, used to make watertight seals in plumbing. Pratley's Putty is an adhesive used primarily for steel bonding. Certain types of putty also have use in the field of terminal ballistics, where the putty can accurately represent the average density of the human body. As such it can be used, for instance, to test the penetrative power of projectiles, or the stopping power of body armour. Play putty, such as "silly putty," is for children to play