When the European Space Agency (ESA) announced it was looking for astronauts, over 8,400 people applied. The online application was in English and required a university degree in natural science, engineering or medicine. Only citizens of an ESA member state were eligible to apply, and the age limit was 55. Although a private pilot medical certificate was required, actual pilot experience was not. Bonus points, however, were earned for a PhD or a pilot’s license.
From the initial pool, 902 (11%) candidates were invited to the first phase of aptitude testing in Hamburg, Germany. There were 162 (18%) female candidates, and the ages of the candidates ranged from 24 to 46. Over 50% of the candidates were citizens of France, Germany, and the United Kingdom, collectively.
Of the 902 candidates who participated in the first phase, 192 (21%) advanced to the next phase in Cologne, Germany. These tests concentrated on psychological testing, which is essential to assure a candidate can withstand the confinement in space over several months aboard the International Space Station. Of the 192 candidates who participated in the second phase, only 46 (24%) were recommended for medical screening.
The aptitude and psychological tests used were, in part, based upon the exams for pilots and air traffic controllers. Therefore, the test scores of astronaut candidates were compared with the test scores of pilots. Astronaut candidates scored better than pilots in English proficiency, technical comprehension and mental arithmetic. Airline pilots, however, scored better than astronaut candidates on operational tests. The differences in the scoring may arise because astronaut candidates have scientific careers and are not operationally trained. In contrast, airline pilots are intensively trained in the operation of aircraft. These results showed that specific tests are needed that focus on the unique traits to select astronauts who are made of the right stuff.