also satisfy security requirements, as the role would almost certainly involve the handling of classified information. The decision to restrict selection to military test pilots was taken by Glennan, Dryden and Gilruth in the last week of December 1958, but the irony of using military test pilots in a civilian program was not overlooked, and in view of the President's express preference for a space program outside the military, Glennan thought it best to run the decision past Eisenhower. A meeting was arranged with the President, who was convinced by the arguments. The panel also drew up selection criteria. Astronauts had to be: Less than 40 years old; Less than tall; In excellent physical condition; With a bachelor's degree or equivalent; A graduate of test pilot school; With a minimum of 1,500 hours total flying time; and A qualified jet pilot. The height limit was a function of the design of the Mercury spacecraft, which could not accommodate someone taller. It was still uncertain as to whether piloting in the conventional sense would ever be possible in a spacecraft, but from the beginning the spacecraft design provided for some degree of manual control. Selection process The first step in the selection process was to obtain the service records of test pilot school graduates from the United States Department of Defense. All services agreed to cooperate fully, and handed over their records. There were 508 military test pilots in total, of whom 225 were Air Force, 225 Navy, 23 Marine Corps and 35 Army. Donlan, North, Gamble and psychologist Robert B. Voas then went through the records in January 1959, and identified 110 pilots – five Marines, 47 from the Navy, and 58 from the Air Force – who met the rest of the minimum standards. The 110 were then split into three groups, with the most promising in the first group. Sixty-nine candidates were brought to the Pentagon in Washington, DC, in two groups. The first group of 35 assembled there on February 2, 1959. The Navy and Marine Corps officers were welcomed by the Chief of Naval Operations, Admiral Arleigh Burke, while the Air Force officers were addressed by the Chief of Staff of the United States Air Force, General Thomas D. White. Both pledged their support to the space program, and promised that the careers of volunteers would not be adversely affected. NASA officials then briefed the candidates