At the time NASA was established in 1958, there were no real answers to what an astronaut must do or be. But some experience with high altitude flight and considerable speculation and extrapolation suggested what might be reasonable criteria for being an astronaut.

In February 1957, the School of Aviation Medicine at Randolph Air Force Base in Texas, published the results of an investigation regarding the “Selection and Training of Personnel for Space Flight.” The authors presumed that the return of a spacecraft into the atmosphere would require an extended glide and a conventional landing of a winged craft with a tricycle landing gear–a premise that would fit the Shuttle two decades later but not the intervening Mercury, Gemini and Apollo spacecraft. They reasoned that training and experience in piloting jet and rocket aircraft, such as the X-15 then being developed, would be “most useful for transition to spacecraft.” Current hypotheses for space launches, they said, citing Werner von Braun among others, indicated an acceleration force of 9g’s on the crew and a configuration approximating contemporary jet aircraft, but with a much more complex instrumentation and control system. Given these parameters, the spacecraft pilot fit the mold of “experienced pilots of high performance aircraft.” But the critical elements in the selection, they believed, related more to the psychological than to the physical aspects of spaceflight, for “by far the greatest problem involves the implications of a seemingly complete break from the Earth and the protective societal matrix in a small, isolated, closely confined container with few companions.” An astronaut candidate, they believed, must “manifest intense motivation for the project,” have a strong ability to cooperate to the point that they could place trust and confidence in associates and win the trust and confidence of those associates. They should have “positive interpersonal attitudes, mature character integration, and emotional stability involving an inner sense of duty, responsibility, self-control and restraint.” And they had to be adventurous but not foolhardy. Although space flight would not be drastically different from aeronautical flight, they admitted that the first space crews would be pioneers who would have to be “their own instructors,” but they believed that astronauts would require academic training in “applied and theoretical mathematics, electronics, engineering, navigation, astronomy and astronavigation,” as well as intensive courses on the design and construction of the spaceship, instruction in “basic spatial medicine,” and training in simulators and near-space conditions. The report intimated that the physical, psychological and mental demands on an astronaut would be very great indeed.

With the establishment of NASA in 1958, selecting men for spaceflight became a pressing matter. In November of that year, the NASA administrator appointed a team of “aeromedical consultants” from the military services for temporary assignment to NASA, later becoming the nucleus of the NASA permanent biomedical team. The initial group of medical advisors included a specialist in human factors engineering and biotechnology, a psychologist whose early duty involved military pilot selection, a physician specialist in human physiology, and another physician who was the chief of flight medicine for the USAF.  In addition to the biomedical team on October 1958, the NASA administrator established a non-NASA, independent Life Sciences Advisory Committee to recommend programs and to assist in defining the qualifications and selection processes for the first astronauts to fly the Mercury capsule. The head of the committee (Dr. Lovelace) was a pioneer in high-altitude, near-space flight studies. Years before he had investigated the effects of an extremely high-altitude parachute jump by personally bailing out at 36,000 feet. The Life Sciences Committee produced a set of very broad specifications. They urged the selection of astronauts from the more dangerous professions, such as race car drivers, mountain climbers, scuba divers, or test pilots.

At this point, President Eisenhower personally intervened to specify that astronauts must be selected from the rolls of current military test pilots. The selection criteria were then condensed by NASA’s management into a simplified list of seven points. Astronaut candidates must:

1) Have a degree or the equivalent in physical science or engineering
2) Be a graduate of a military test pilot school
3) Have at least 1500 hours flying time including a substantial amount in high performance jets
4) Be younger than 40
5) Be no taller than 5’11”
6) Be in superb physical condition
7) Possess psychological attributes specified by the Life Sciences Committee

By these specifications the pool of candidates for the astronaut corps would be largely male by virtue of the heavily male-dominated fields of engineering and physical sciences, and by virtue of the prerequisite for test pilot experience. Although 13 women applied for the astronaut corps in 1960, and passed the strict physical and psychological tests, none were admitted into the astronaut corps until 1978 when 5 women became astronauts.

The selection process started with the review of the records of 473 military test pilots leading to the selection of 110 pilots as potential candidates divided into 3 groups. Each group was then invited for a preliminary briefing and personal interviews. Of the 63 interviewed in the first 2 groups, 80% indicated they were interested and would be available for more rigorous testing. After personal consultations and more interviews, the list of candidates was narrowed to 32 individuals, and the third interview group was canceled. Next they were divided in five groups of six and one group of two, and subjected to an exhaustive series of physical and psychological examinations. One astronaut, Michael Collins, several years later when the examination procedures had been somewhat moderated, described the procedure and NASA later incorporated his description in the official record as an example of a “humanistic perspective of what all those tests were like”: Inconvenience is piled on top of uncertainty on top of indignity, as you are poked, prodded, pummeled, and pierced. No orifice is inviolate, no privacy respected ….cold water is poured into one of your ears, causing your eyeballs to gyrate wildly as conflicting messages are relayed to your brain from one warm and one cold semicircular canal. Your body is taped with electrocardiogram sensors and you are ordered onto a treadmill, which maintains its inexorable pace up an imaginary mountain road. As the tilt becomes steeper, the heart rate increases, until it finally reaches 180 beats per minute. A psychological and stress evaluation of the astronaut candidate was conducted by the Air Force at the Wright Air Development Center Aeromedical Laboratories at Wright-Patterson Air Force Base in Dayton, Ohio. One of the tests was to lock the candidate alone in a totally dark room for an extended time. The first group of candidates began their 6 days of psychological evaluations in February. The final step in the selection process occurred at Langley Research Center where a group representing both the medical and technical fields evaluated the data identifying those meeting the basic physical and psychological requirements. The final decision, however, rested largely on the nontechnical evaluation of the person’s resourcefulness, interest in the manned spaceflight program, and “survivor” instincts. A good number of the prospective astronauts, however, earlier withdrew from consideration because they believed that the space program might be very short-lived, and because it did not seem to contribute to their promotion and career enhancement as military officers. Moreover, many pilots and the Experimental Test Pilots Association believed that the Mercury program did not truly require the skills of a test pilot. In a 2-hour meeting, the review committee selected seven finalists. Those seven were invited to NASA Headquarters where their names were publicly announced at a press conference on April 9. They were:

Lieutenant Malcolm S. Carpenter, U.S. Navy
Captain Leroy G. Cooper, Jr., U.S. Air Force
Lieutenant Colonel John H. Glenn, Jr., U.S. Marine Corps
Captain Virgil I. Grissom, U.S. Air Force
Lieutenant Commander Walter M. Schirra, U.S. Navy
Lieutenant Commander Alan B. Shepard, U.S. Navy
Captain Donald K. Slayton, U.S. Air Force

Specifications for the second field of astronaut candidates changed slightly, but significantly. The age limit was lowered from 40 to 35, educational qualifications were broadened to include degrees in biological sciences, and while flight experience required “experience as a jet test pilot,” that experience could be achieved through the aircraft industry or NASA or by having graduated from a military test pilot school. Thus, the second astronaut draft opened the door to civilians and to persons with scientific as well as engineering credentials. In 1963, for the third recruiting effort, flight requirements were lowered to 1000 hours, non-test pilots were qualified, and the age limit was lowered to 34. Instead of prospective candidates being prescreened by NASA or by the military services, the call extended to volunteers from industry, professional groups, and other organizations. There was more emphasis on academic credentials, but most of the astronauts for the first three groups (24 of 30) still came from the military.

The fourth group was different. Its selection followed several years of discussion and some controversy relating to the perceived need for astronauts with strong scientific training for the lunar missions. The Space Sciences Board of the National Academy of Sciences conducted a preliminary study of space research needs in 1962, and in 1963 a special ad hoc committee, retained by submitted a report on “Apollo Experiments and Training on the Scientific Aspects of the Apollo Program.” As a result of this work, NASA decided that astronaut selection should be based on both scientific and operational criteria, but that “because of the complex and difficult operational requirements and crew safety, whenever conflict exists between operational and scientific requirements, flight safety considerations demand that the scientific requirements be subordinate to the operational requirements”. Subsequently, the NASA Office of Space Science and Applications cooperated with the National Academy of Sciences in defining specific scientific qualifications desired for the scientist-astronauts to be trained for lunar expeditions. The Office of Manned Space Flight defined the other-than-scientific requirements, notices for applicants were published and distributed in October, November, and December of 1964, and applications were due by January 1, 1965. Height, experience or training was not required of these candidates. The applicants were then reviewed by the National Academy of Sciences which ranked the top 50 applicants on the basis of their scientific qualifications. Finally, on June 28, 1965, NASA selected six finalists from the Academy list. The finalists all had M.D. or Ph.D. degrees, two were medical doctors, two were engineers, one a physicist, and one a geologist. All but one were civilians.

The fifth group, selected in 1966, met the requirements established for Group III, but the age limit was raised from 34 to 36. NASA selected 19 astronauts, 4 of whom were civilians, in this round. The next year, 1967, the National Academy of Sciences again screened candidates as in 1965, and NASA selected 11 finalists, all of whom had Ph.D. or M.D. degrees, all of whom were civilians, and were required to attend jet pilot school for a year before beginning their regular training program. A seventh group of astronauts joined NASA in 1969, as transfers from the Manned Orbiting Laboratory Program being canceled by the Department of Defense. Seven transfers were accepted on the basis of their Air Force program qualifications, and by virtue of the fact that they were under 36 years of age.

Nine years passed before NASA recruited any additional astronauts for spaceflight programs. A new-generation space vehicle, the Shuttle, would be manned by new generation astronauts. NASA had last recruited astronauts in 1966 and 1967. The class of 1966 comprised 19 pilot astronauts, and in 1967, 11 scientist astronauts were selected for the lunar science missions. In 1978, both pilot astronauts and astronaut mission specialists were recruited. From over 8000 qualified applicants, NASA chose 15 pilot astronauts and 20 mission specialists. Pilot astronauts needed a minimum B.S. or B.A. degree in engineering, biological, or physical sciences with an advanced degree preferred and a minimum of 1000 hours of high performance jet aircraft experience. Mission specialists (and payload specialists) did not need flight time or pilot experience and were subjected to a less rigorous physical examination than the Class I flight physical, but academic credentials and psychological testing weighed heavily in the selections. Reflecting the growing national concerns about opportunities for minorities, affirmative action, and civil rights, NASA’s first Shuttle class included six women and four minority candidates.

Adapted from NASA-SP-4307 “Suddenly, Tomorrow Came