Mounting pressure in the early 1960s from the National Academy of Sciences (NAS) to study ways of expanding the role of astronauts to conduct science on future space missions led to NASA's conclusion that flying scientifically trained crewmembers would generate greater returns from each mission. NASA and industry studies continued investigating possibilities that could lead to the eventual creation of the first space stations using surplus Apollo hardware, through the Apollo Applications Programme (AAP). There was also a growing interest within the military to create their own manned space...