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Astronaut Selection for the Mercury Flights

Table of Contents


Testing Background

Who’s Going?

Testing Guidelines and Tests

The Choices


The selection of the Mercury 7 was to be born from the establishment of the President’s Scientific Advisory Committee in November of 1957. Upon passage of the National Aeronautics and Space Act of 1958, a civilian space agency was tasked to choose individuals with the “right stuff”. To this end, a Space Task Group, or STG, was formed at Langley Field, Virginia.
At the early stages of the American space program, many questions needed to be addressed. Was it possible for a human to aptly control a spacecraft in the conditions of weightless flight? If so, who would they be, and from what background?

A combination of pure conjecture and real experience with high-performance aircraft operations was to become the basis of the characteristics determined. The primary task for an astronaut, as the STG saw it, was to survive, or to demonstrate the ability of man to fly in space and to return safely. Secondarily, the astronaut would have to demonstrate man’s capacity to act usefully under conditions of space flight. The astronaut could also serve as a backup system for all the automatic controls, and this would increase the reliability of spacecraft systems. Finally, the STG concluded, the astronaut would function as a scientific observer and go beyond what the instrumentation and unmanned satellites were able to observe and report. (WWW-1)

Based on these criteria the STG utilized a variety of tests ranging from stringent physical, psychological, and mental examinations to brutal interviews.

Testing Background

In 1952, the Aeromedical Research Laboratory (AMRL) initiated a new program at the behest of the Human Factors Division of the Air Force Research and Development Command. This program was to select aviators for special high altitude research flight. These flights, which at the time were classified, included the U-2 surveillance flight program. In 1957 Colonel Don Flickenger designated the AMRL the center of medical research for the USAF initiative, “Man in Space”. (Santy, 2)

Pilot screening had been an essential part of any military flight endeavor since the end of WW-I. Casualties of this war had made it clear to officials that not everyone was suited to be an aviator. There was a large attrition rate in flight training as well, so the Army Air Force psychology personnel developed a screening system called the stanine.

This program tested on common sense and practicality and used test scores that ranged form one to nine. A candidate would be asked to look at a map, for example, then smaller segments of the map. He then was asked to determine which of the smaller segments was included in the large map. Other tests would include visualization and psychomotor skills that were a routine part of being a pilot. (Santy, 2)

Scoring a seven, eight, or nine, would mean that the candidate could probably complete the flight training successfully. These tests were not one hundred percent accurate but were guidelines that helped trim the cost of training and lesson the dropout rate. (Santy, 2)

As the AMRL progressed toward the Man in Space program, other aspects of testing were conducted as well. Stress testing had become an interest to the AMRL. Using a B-17 aircraft they conducted experiments on crew interaction and fatigue. Crews would be wired so that their heart rate, blood pressure, temperature, respirations, and skin resistance could be monitored. These tests were conducted at high altitudes and over long periods of time. (Santy, 3)

Isolation tests were conducted on groups of men who were confined for days at a time. Each subject was tested for physiological and biochemical changes in perception, cognition, and group interactions. It was thought, and later observed, that the isolation tests re-created many of the same conditions found on long high-altitude surveillance missions. The AMRL was slowly proceeding with these tests until on October 4, 1957 an event would change the course of history. (Santy, 3)

When the Soviet Union launched Sputnik I a sort of national panic ensued as Americans were not used to being upstaged in the science and technology sector. The public out-cry, as well as the private disdain in the political sector, prompted the Eisenhower administration to action. In November of 1957 the President’s Scientific Advisory Committee recommended the induction of a civilian space agency, and the National Aeronautics and Space Administration, or NASA, was born. (WWW-2)

Who’s Going?

Project Mercury began on October 7, 1958, one year and three days after the Soviet Union launched Sputnik 1 and was the United States' first manned space program. The objectives of the program, which were made up of six manned flights from 1961 to 1963, were specific:

1. To orbit a manned spacecraft around Earth,

2. To investigate man's ability to function in space and

3. To recover both man and spacecraft safely.

NASA took charge of the quest for space and began screening potential candidates for this new project.

This process was, at first, open to all walks of life. The new agency considered whom the best-qualified people for the task would be, and came up with a list of occupations that met the criteria. These occupations included aircraft pilots, but it also included balloonists, submariners, deep-sea divers, mountain climbers, explorers, flight surgeons, and scientists.2 If it weren’t for a white house mandate that all candidates be military test pilots with 1500 hours of flying time in high performance jets, the configuration of NASA might be drastically different today. As it was, however, the decision by Eisenhower greatly reduced the heterogeneity of applicant possibilities. NASA then looked at what kind of testing could and should be done, and decided to seek the help of the AMRL. (Santy, 5)

Testing Guidelines

Dr. George Ruff ran the department of the AMRL that would conduct the testing. Although Ruff and his staff of psychologists were in charge of the testing, all branches of the military were to be involved in the selection process. The representative from the Navy was Dr. Robert Voas, a member of the STG, and flight surgeon William Augerson represented the Army. (WWW-3)

The AMRL was thrilled to become involved in the process as they saw it as a wonderful opportunity to further their studies on crew isolation and adaptation. What better environment than space, the most hostile and isolated environment imaginable, to conduct testing. It was thought that space flight would subject the astronaut to all kinds of conditions that Ruff and his staff had previously tested on; high acceleration, reduced pressure, heat, noise, vibration, and weightlessness. These factors would serve to adversely affect the performance of the pilot. (Santy, 5)

Captain Ruff’s team was made up of Captain Edwin Levy, psychiatrist: Captain Victor Thaler, Captain John Jackson, Dr. Mildred Mitchell, and Lieutenant Gilbert Johnson. (Santy, 5)

With Ruff and Levy in charge, the team developed a basic philosophy that would guide it in the psychiatric screening of those remarkable men who wanted to fly in space. Ruff wrote later that the ‘concept underlying the astronaut selection program deviated little from that stated by Plato over 2000 years ago’ “ In the first place, no two persons are born exactly alike, but each differs from each in natural endowments, one being suited for one occupation and another for another” (Santy, 6)

After establishing the initial philosophy the team then had to design testing specifics and procedures. The first challenge was to specifically outline the job of an astronaut. The tasks of the job would dictate the qualifications of the applicants. (WWW-2)

After careful consideration the group decided upon the following tasks that the astronauts would have to accomplish:

1. Sequence monitoring: Monitoring all the critical phases of the space mission, such as the staging of the booster, the separation of the escape tower, the firing of the retrorockets, and the deployment of the parachutes;

2. Systems management: Operating all the onboard systems and managing the critical consumable supplies so as to ensure that any out-of-tolerance condition is recognized and corrected before a critical situation develops;

3. Attitude control: Maneuvering the vehicle to the proper relationship to Earth whenever it is required during the mission; and
4. Research observations: Carrying out the special activities related to research and the evaluation of spacecraft function under flight conditions.

Additional requirements that each of the candidates would have to meet included a high skill level in a pilot’s role, “appropriate” personal characteristics, a high level of physical fitness, a good knowledge of engineering and operational procedures, a broad general scientific knowledge and research skills, high intelligence, and excellent psychomotor skills. (Santy, 11)

Once personal characteristics were determined, Ruff’s team established eight guidelines of what was to be expected of the candidates and seventeen categories on which each candidate would be rated. (Santy, 11) The guidelines were as follows:

1. Candidates should have a high level of general intelligence, with abilities to interpret instruments, perceive mathematical relationships, and maintain spatial orientation.

2. There should be sufficient evidence of drive and creativity to ensure positive contributions to the project as a whole.

3. Relative freedom from conflict and anxiety is desirable. Exaggerated and stereotyped defenses should be avoided.

4. Candidates should not be overly dependent on others for the satisfaction of their needs. At the same time, they must be able to accept dependence on others when required for the success of the mission. They must be able to tolerate either close associations or extreme isolation.

5. The astronaut should be able to function when out of familiar surroundings and when usual patterns of behavior are impossible.

6. Candidates must show evidence of ability to respond predictably to foreseeable situations, without losing the capacity to adapt flexibly to circumstances that cannot be foreseen.

7. Motivation should depend primarily on interest in the mission rather than on exaggerated needs for personal accomplishment. Self-destructive wishes and attempts to compensate for identity problems or feelings of inadequacy are undesirable.

8. There should be no evidence of excessive impulsivity. The astronaut must act when action is appropriate, but refrain from action when inactivity is appropriate. He or she must be able to tolerate stress situations positively, without requiring motor activity to dissipate anxiety. (Santy, 11)

The astronauts were evaluated on the previous guidelines by the following categories using a ten point grading scale.

1. Drive: An estimate of the total quantity of instinctual energy.

2. Freedom form conflict and anxiety: A clinical evaluation of the number and severity of unresolved problem areas and of the extent to which they interfere with the candidate’s functioning.

3. Effectiveness of defenses: How efficient are the ego defenses? Are they flexible and adaptive or rigid and inappropriate? Will the mission deprive the candidate of elements necessary for the integrity of his defensive system?

4. Free energy: What is the quantity of the neutral energy? Are defenses so expensive to maintain that nothing is left for creative activity? How large is the “conflict-free” sphere of the ego?

5. Identity: How well has the candidate established a concept of himself and his relationship to the rest of the world?

6. Object relationships: Does he have the capacity to form genuine object relationships? Can he withdraw object cathexes when necessary? To what extent is he involved in his relationships with others?

7. Reality testing: Does the subject have a relatively undistorted view of his environment? Have his life experiences been broad enough to allow a sophisticated appraisal of the world?

8. Dependency: How much must the candidate rely on others? How well does he accept dependency needs? Is separation anxiety likely to interfere with his conduct of the mission?

9. Adaptability: How well does he adapt to changing circumstances? What is the range of conditions under which he can function? What are the adjustments he can make? Can he compromise flexibly?

10. Freedom from impulsivity: How well can the candidate delay gratification of his needs? Has his behavior in the past been consistent and predictable?

11. Need for activity: What is the minimum degree of motor activity required? Can he tolerate enforced passivity?

12. Somatization: Can the candidate be expected to develop physical symptoms while under stress? How aware is he of his own body?

13. Quantity of motivation: How strongly does he want to participate in the mission? Are there conflicts between motives-whether conscious or unconscious? Will his motivation remain at a high level?

14. Quality of motivation: Is the subject motivated by a desire for narcissistic gratification? Does he show evidence of self-destructive wishes? Is he attempting to test adolescent fantasies of invulnerability?

15. Frustration tolerance: What will be the result of failure to reach established goals? What behavior can be expected in the face of annoyances, delays, or disappointments?

16. Social relationships: How well does the subject work with a group? Does he have significant authority problems? Will he contribute to the success of missions for which he is not chosen as pilot? How well do other candidates like him?

17. Overall rating: An estimate of the subject’s suitability for the mission. This is based on interviews, test results, and other information considered relevant.

These categories are not independent of each other but instead are related to one another on abstract levels. Several categories were included because of a correlation to specific outlined Mercury missions. (eg., 8,9, and 11-16) (Santy, 12-13)

Ruff’s team devised other means of measuring qualifications as well. There was the psychiatric interview, personality tests, performance tests, and ability and intelligence tests.

The psychiatric interview was designed in two sessions. The first would look at the candidate’s life history and current life adjustment. The second was fairly unstructured and allowed the candidate to “sell himself” much like a job interview. In the first interview candidates were asked questions regarding their adolescence, their families, and their goals in life. During the second interview they were quizzed on why they wanted to be a part of the Mercury program, among other things. (Santy, 11)

The personality tests were also designed in two sections. The first was called projective personality testing, which created a situation in which the psychological issues of the person taking the test could be reflected. Testing in this area was done on the following: (Santy, 230)

1. Rorschach Ink Blot Test: A subjects associations to ten ambiguous inkblots are observed and scored. The test yields information about emotional conflicts and defense mechanisms.

2. Thematic Apperception Test (TAT): A series of pictures depicting situations about which the subject must make up story. Multidimensional analysis of responses is possible.

3. Draw-A-Person: The subject is asked to draw a picture of a person, and one of the opposite sex. The results of the drawings yield information about self-concept, ego boundaries, and possible conflict areas.

4. Sentence Completion Test: Subjects are asked to complete sentences such as “my Mother…….”. Results cover potential conflict areas.

5. Who Am I?: Twenty answers to the question “Who am I?” are written by the subject, and is an assessment of identity and social role perception.

The second type of test was the objective test. These tests are generally self-report questionnaires. The tests are standardized against a normal population. These tests included: (Santy, 230)

1. Minnesota Multiphasic Personality Inventory (MMPI): The subject must choose from 566 true or false items.

2. Gordon Personal Profile: A self-administered, eighteen tetrad personality inventory for which the subject chooses “best” or “least” to describe himself. The results report on ascendance, responsibility, emotional stability, and sociability.

3. Edwards Personal Preference Schedule: A 247 item personality inventory for which the subject chooses one of two phrases that best describes himself. The test is scored on sixteen personality traits: achievement, deference, order, exhibition, autonomy, affiliation, introspection, succorance, dominance, abasement, nurturance, change, endurance, heterosexuality, aggression, and consistence.

4. Shipley Personal Inventory: Another self descriptive test which differentiates between normal and psychiatrically undesirable applicants. The test consists of twenty pairs of descriptive statements.

5. Outer-Inner Preferences: A fifty-two question test of two possible answers measuring how the candidate feels about activities, other people, and dependency on social groups.

6. Pensacola Z: A test measuring authoritarian attitudes using sixty-six questions from which the subject chooses the best answer.

7. Officer Effectiveness Inventory: A multiple-choice test measuring officer performance.

The performance tests were designed by the medical team and measured the ability of the candidate to function and perform under stressful conditions utilizing complex psychomotor and cognitive skills. The first of the two performance tests, the Peer Ratings test, required each subject to choose which of his fellow candidates he liked best, which he would prefer to join him on a two-man mission, and who he would have take his place, should he not be able to go himself. The second was the Complex Behavior Simulator. This test was designed to simulate the job characteristics of a systems operator. The task was to monitor a steady stream of single letters given in Morse code at five second intervals. The subject was given a clicker device and was told to notify when a single letter was heard three times in a one-hour period. Successful completion of this test would be a one hundred percent signal recognition and five successively correct identifications of randomly sequenced three-signal series. (Santy, 231-232)

Finally, the Tests of Ability and Intelligence would include:

1. Wechsler Adult Intelligence Scale (WAIS): A test measuring verbal and performance functions.

2. Miller Analogies: Intelligence test comprised of 100 multiple choice paired analogies measuring general intelligence and verbal achievement.

3. Raven Progressive Matrices: A test of non-verbal concept formation.

4. Doppelt Mathematical Reasoning Test: A timed group test consisting of fifty complex mathematical multiple-choice questions.

5. Minnesota Engineering Analogies: A fifty item engineering knowledge test. The test combines abstract reasoning and engineering achievement.

6. Mechanical Comprehension: A test measuring the comprehension and application of mechanical principles.

7. Air Force Officer Qualification Test: U.S. Airforce test measuring verbal ability and quantitative aptitudes.

8. Aviation Qualification Test: U.S. Navy academic achievement test.

9. Space Memory: A spatial arrangement test utilizing memory of locations of objects in space.

10. Spatial Orientation/Spatial Visualization: This test measures the ability to match photographs with maps by measuring the time needed to locate details in aerial photographs.

11. Gottschaldt Hidden Figures: The subject is asked to locate a particular item imbedded in a mass of irrelevant details. This test assesses visual perception and analytical ability.

12. Guilford-Zimmerman Spatial Visualization: A test measuring the ability to manipulate ideas visually. A test designed to screen engineers, architects, and draftsmen.

Once Dr. Ruff and his staff had mapped out the objectives, testing guidelines, and testing procedures, the time had arrived to screen for candidates that would compete for slots in Project Mercury. (Santy, 13-15)

The Choices

In January of 1959, astronaut selection began with a panel consisting of Dr. Stanley White/physician, Dr. Robert Voas/psychologist, George Ruff/psychiatrist, Edwin Levy/psychiatrist, Dr. William Augerson/surgeon, Charles Donlon/assistant director-Project Mercury, Allen Gamble/psychologist, and Warren North/Chief of Space Flight Programs. Of a total of five hundred and eight service records screened, one hundred and ten men were found to meet the minimum standards set forth earlier. This list of names included five Marines, forty-seven Navy men, and fifty-eight Air Force pilots. Several Army pilots' records had been screened, but due to Eisenhower's test pilot school graduate requirements, none were selected. The selection process began while the possibility of manned Redstone flights in late 1959 still existed on paper. (WWW-2)

Charles Donlan arbitrarily divided the list of one hundred and ten men into three groups and issued invitations for the first thirty-five to come to Washington at the beginning of February for briefings and interviews. Twenty-four of the first group interviewed accepted participation in the Mercury program. The following week the second group arrived in Washington. Due to the high volunteer rate of the first two groups the decision was made not to invite the third group. An excerpt of a report made by George Low: (WWW-3)

"During the briefings and interviews it became apparent that the final number of pilots should be smaller than the twelve originally planned for. The high rate of interest in the project indicates that few, if any, of the men will drop out during the training program. It would, therefore, not be fair to the men to carry along some who would not be able to participate in the flight program. Consequently, a recommendation has been made to name only six finalists." (WWW-3)

Of the sixty-nine men that had reported to Washington by the middle of February, twenty-one were eliminated for medical, technical, or psychological reasons and another sixteen declined to participate or dropped out. This reduced the total at the beginning of March to thirty-six men. Thirty-two accepted and became candidates. The men were assured that by participating, none would jeopardize their military careers, as all of the testing and medical findings would remain classified and not be included in their service records. (WWW-3)

The candidates were sent to Albuquerque to undergo approximately a week of medical evaluations. Over 30 different laboratory tests collected chemical, encephalographic, and cardiographic data. X-ray examinations thoroughly mapped each man's body. The ophthalmology section and the otolaryngology sections likewise learned almost everything about each candidate's eyes, and his ears, nose, and throat. Special physiological examinations included bicycle ergometer tests, a total-body radiation count, total-body water determination, and the specific gravity of the whole body. Heart specialists made complete cartiological examinations, and other clinicians worked out more complete medical histories on these men than probably had ever before been attempted on human beings.6 The selectees were found to be so healthy that only one had medical problems significant enough to be eliminated.

Each of the thirty-one subjects spent another week during March experiencing a wide range of stressful conditions. In addition to pressure suit tests, acceleration tests, vibration tests, heat tests, and loud noise tests, each candidate had to prove his physical endurance on treadmills, tilt tables, with his feet in ice water, and by blowing up balloons until exhausted. (WWW-3)

The final evaluation of data was made by correlating clinical and statistical information from each of the testing procedures. Eighteen of the thirty-one candidates were recommended without medical reservations for final consideration.

According to Donlan "although the physicians, psychiatrists, psychologists, and physiologists had done their best to establish gradations, the attrition rate was too low. So the final criteria for selecting the candidates reverted to the technical qualifications of the men and the technical requirements of the program. We looked for real men and valuable experience." (WWW-3)

With the list being pared to eighteen finalists, Donlan, White, and North shaved the final pool of selectees, choosing each one to complement the others. The difficulty of reaching six astronauts was so great that Gilruth decided to recommend seven. Donlan telephoned each of the seven individually to ask whether he was still willing to accept a position as a Mercury astronaut. Each one gladly volunteered again.

On April 2, 1959, from the United States Marine Corps, Lieutenant Colonel John Herschel Glenn, Jr., from the Navy, Walter Marty Schirra, Jr., and Alan Bartlett Shepard, Jr., Lieutenant Commanders, Lieutenant Malcolm Scott Carpenter, and Air Force Captains, Donald Kent Slayton, Leroy Gordon Cooper, Jr., and Virgil I. Grissom reported to duty as the Mercury Seven. (WWW-3)

“Man’s profoundest aspiration is to know himself and his universe and life’s deepest passion is a desire to become godlike. All men must balance their hubris with their humility” –Bertrand Russell

Figure 1 The Mercury 7 (WWW-2)


Ackmann, Martha, The Mercury 13, 2003, Random House, USA

Santy, Patricia, Choosing The Right Stuff, 1994, Praeger Publishers, USA

Accessed: March 5, 2004

Accessed: March 5, 2004

Accessed: March 7, 2004