The first astronauts intake was drawn from the ranks of military test pilots. The service records of 508 graduates of test pilot schools were obtained from the United States Department of Defense. From these, 110 were found that matched the minimum standards: the candidates had to be younger than 40, possess a bachelor's degree or equivalent and to be or less. While these were not all strictly enforced, the height requirement was firm, owing to the size of the Project Mercury spacecraft. DPP was restricted to those with bachelor's degrees, so it was assumed that Carpenter had one.