The way by which NASA selects their astronauts is rather unique. It is actually a two phase process in which during the first phase, astronauts are accepted as candidates. They are accepted out of literally thousands of men and women who apply for admission to the Astronaut Candidate Training Program. The people who are accepted for the Astronaut Candidate Training Program will then go on to go through the rigorous two year training program.
Applicants who apply to be accepted as Astronaut Candidates are applying for two positions: pilot astronaut or mission specialists. The third area, payload specialist is a full fledged astronaut, but they typically work for the company whose equipment is going on the mission in the cargo bay.
Most of the people who are selected to be pilot astronauts are actual test pilots who have considerable flying experience from the military – either the Air Force, Navy or Marine Corps. Because NASA is a government agency, astronauts who are hired as pilot astronauts and who come from branches of the military are paid according to their military rank.
The second type of astronaut that NASA selects is a mission specialist. They work closely with pilots to maintain both the equipment on board and the spacecraft itself. Mission specialists come from diverse backgrounds ranging from medical doctors to scientists or engineers. Some astronaut candidates may come from institutions that are associated in some way with NASA such as the Jet Propulsion Lab. The one thing they all have in common is extensive research backgrounds.
Mission specialists do everything from launch satellites to conducting experiments or going on spacewalks that require them to perform tasks outside the spacecraft. All of the Hubble Telescope Servicing missions are examples of the extravehicular tasks that astronauts may be called upon to perform.
Mission specialists who are in the Armed Forces are paid according to their military rank, but civilian astronauts are assigned to civil service ranks, as are all non-elected and appointed government employees. They are paid according to the civil service rank.
Some of the equipment that astronauts take on missions is what one would refer to as payload equipment. The astronauts who are payload specialists are usually scientists who work for the company that owns or makes the equipment, not for the government. Nonetheless, they still must be approved by NASA before they can participate in any mission. They will perform experiments using the payload equipment that is stored in the spacecraft’s cargo bay. The robotic arm is an example of payload equipment.
The training program is extremely rigorous, and there is no guarantee that upon completion, one will be accepted as astronauts. The first phase of the Astronaut Candidate Training Program involves classroom work. Astronauts will learn about all sorts of technical things associated with the spacecraft and space. Experienced astronauts, instructors from NASA, engineers, academicians and guest speakers will provide the information in the classroom phase of training.
The first week an astronaut enters the training program, they are required to take swimming tests. They will have to swim three laps of a 25 meter pool without stopping. The second test is a repetition of the previous one, but they have to wear a flight suit and sneakers. For the third test, they must tread water continuously without stopping for 10 minutes.
During the second phase of the training program, astronauts will do the practical and hands on work. Part of that training involves taking SCUBA diving lessons and becoming certified SCUBA divers. They will also learn to fly, spend time in life size mockups of the Space Shuttle, learn how to cook their own food, do maintenance and repairs on the space craft, and even do basic housekeeping things.
They will also learn how to deal with weightlessness, and that involves everything from learning how to exercise in microgravity to learning how to go to the bathroom and what they will have to do for grooming. One of the most important things they learn in training is how to deal with living in such cramped quarters when there is no privacy.
The entire time the astronaut candidates are in training, they are also being evaluated. At the end of the training period, NASA then decides which of the astronaut candidates will be accepted. None of the candidates are guaranteed of acceptance when they begin the program. It is so intense and rigorous, only the most committed, determined and strong people who are willing to do whatever it takes to get through that program are likely to succeed.
Each year, NASA acquires a new class of astronauts. The new astronauts benefit from the knowledge, expertise and training of the more experienced astronauts. Depending on the type of work that they do, astronauts may stay with NASA for only a brief time (5 to 10 years, or less) or they may remain with the program for as much as 20 years.