Apollo 9 to land on the Moon; when the crews for Apollo 8 and 9 were swapped, their backup crews were also swapped. Since the rule of thumb was for backup crews to fly as prime crew three missions later, this put Neil Armstrong's crew (Borman's backup) in position for the first landing mission Apollo 11 instead of Pete Conrad's crew, who made the second landing on Apollo 12. Apollo 9 was the first space test of the complete Apollo spacecraft, including the third critical piece of Apollo hardware besides the command and service module and the Saturn V launch vehicle—the lunar
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