Astronaut

An astronaut is a person trained to work in space, aboard a spacecraft or a space station. The profession requires scientific and technical knowledge, good physical fitness, and the ability to work effectively in a team. Before a mission, astronauts undergo extensive training. They learn to operate spacecraft systems, use specialized equipment, conduct experiments, respond to emergencies, and live for long periods in a confined environment.

They also practise in facilities that reproduce some conditions of spaceflight, including reduced-gravity situations. A mission may last from a few days to several months. During the flight, astronauts follow carefully prepared procedures because ordinary activities can become more difficult in microgravity. Their daily routine may include scientific research, equipment maintenance, exercise, meals, rest, and communication with teams on Earth.

In orbit around Earth, astronauts appear to float because their spacecraft and everything inside it are in continuous free fall around the planet. This produces a sensation of weightlessness, although Earth's gravity is still acting on them. Space missions allow astronauts to study the human body, biology, physics, materials, Earth, and other subjects under conditions that are difficult to reproduce on the ground.

They may also perform spacewalks while wearing specially designed suits that provide oxygen and protection from the vacuum of space, extreme temperatures, and harmful radiation. Safety systems help keep them connected to the spacecraft while working outside. The profession therefore combines scientific preparation, technical skills, teamwork, discipline, careful planning, and the ability to adapt to unusual and demanding conditions.