From 1964 through 1966 George Mueller, chief of manned space flight programs, worked hard to sell an ambitious post-Apollo program to his NASA superiors and to Congress. His Apollo Applications Program (AAP), established in August 1965, contemplated 29 lunar and earth-orbital missions between 1968 and 1971. Two-thirds of them would be manned flights, launched at the rate of eight per year. A manned program of that magnitude seemed to have little chance of becoming reality, but until circumstances forced him to back down from it, Mueller kept the pressure on the field centers to plan for big things.48
At Houston, Bob Gilruth and Deke Slayton - whatever their own views about the probability that such an ambitious schedule could be realized - had to be prepared to furnish crews for whatever emerged as the Apollo Applications Program. If the projected AAP missions should actually materialize, many crews would be needed in short order and training had to begin soon. While the recruitment of scientist-astronauts was under way, Gilruth and Slayton urged that additional pilot candidates be sought at the same time, but Mueller decided to wait until the scientist-astronauts had been chosen.49 When Only six trainees emerged from that selection process, he agreed to go ahead. On September 10, 1965, Headquarters announced it would accept applications for a new class of pilot-astronauts. Qualifications would be the same as they had been for the third group: a bachelor's degree in science or engineering plus 1,000 hours of jet flying time or qualification as a test pilot.50
The announcement yielded 351 applicants - the largest number of pilots ever to apply - of whom 159 met the basic requirements. Final screening during the next four months produced the fifth class of astronaut candidates in April 1966: 19 pilots, 4 civilians and 15 military officers [see Appendix 6]. Eleven of the fifth group held advanced degrees, two of them doctorates.51
48. Compton and Benson, Living and Working in Space, pp. 40-56, 83-86.
49. George E. Mueller to Robert R. Gilruth, Jan. 25, 1964.
50. "NASA To Select Additional Pilot-Astronauts," NASA Release 65-288, Sept. 10, 1965; "U.S. Seeking Astronauts for Apollo," Baltimore Sun, Sept. 11, 1965.
51. "Nineteen Pilots Join United States Astronaut Team," NASA Release 66-77, Apr. 4, 1985; "19 Chosen as Spacemen, Some for Moon Missions," Washington Post, Apr. 5, 1966.