An astronaut is a person who goes into space to accomplish a specific mission. Based on the specific tasks assigned, there are three different categories of astronauts. They are - pilots, mission specialists, and payload specialists. A pilot is in command of the spacecraft. The task of a mission specialist is to carry out space-related experiments, set up satellites, walk in space etc. Payload specialists are scientists who conduct various scientific experiments in space.
There is no specific field from which NASA select its astronauts. People from diverse backgrounds like scientists, engineers, and doctors are eligible for its astronaut training program. However, all the candidates need to clear NASA's space training program to qualify for any mission. For a spacecraft pilot, flight experience of at least 1000 hours in a high-performing jet aircraft, as a command pilot, is a must. Mission specialists should have a minimum of 3 years of mission-related experience. Payload specialists should have good education, and training to perform their experiments in space. Also, they need to be well-conversant in English.
Training is extremely crucial for astronauts, because it helps them to tackle all kinds of emergency situations in a space shuttle. It also helps them get familiarized with the equipment present in a spacecraft, and successfully complete their tasks once they are in space.
A vital part of the training is to train their body for weightlessness. Candidates are boarded in large planes that fly through a number of arcing climbs and dives. During this process, they undergo floating exercises within the aircraft. Another aspect of training is to float the body on the surface of water to get used to the feeling of weightlessness.
The next phase is mission training. Here, the candidates get accustomed with the layout of the cockpit, various systems related to flight controls, handling basic engineering works, and managing equipment in the spacecraft. During the different phases of training, the performance of the candidates is thoroughly evaluated, based on which it is ascertained if the person has the potential to be an astronaut or not. It is not necessary that an astronaut who has successfully completed the initial rounds of training would be sent for a mission immediately.
When a trained astronaut is picked for a specific mission, he undergoes additional training. One such training takes place in simulators. Simulators are devices that are designed to recreate the feeling of being in a spacecraft. The crew members spend almost eight hours a day in these simulators, and practice various aspects of their mission. Through this training, they learn to resolve problems that may occur during their stay in space. This helps the astronauts gain confidence to undertake any kind of unforeseen crisis.
The last session of the training is carried out inside a constructed model of a spacecraft called mock-up. Here, the astronauts get habituated to work and live within its confines. They are trained for simple daily activities like storing items, preparing food etc., which are the basic functions that need to be carried out on board the spacecraft. They also practice entering, and leaving the spacecraft. A first-time astronaut has to go through this mission training for 18 months, whereas seasoned veterans undergo the training for 6 months.
Astronauts' training is very rigorous and needs a lot of time and hard work. This training though, could make all the difference between a successful and unsuccessful mission.