Astronauts have to perform many different duties that involve leaving their spacecraft. The International Space Station, which is currently under construction, requires many adjustments that can only be done by trained personnel. Robotic equipment is used to put the components of the space station together, but much of the construction can only be done by hand. Astronauts also have to make repairs to complicated items such as the Hubble Space Telescope and damaged satellites.
Astronauts perform many tasks as they orbit Earth. The space station is designed to be a permanent orbiting research facility. Its major purpose is to perform world-class science and research that only a microgravity environment can provide. The station crew spends their day working on science experiments that require their input, as well as monitoring those that are controlled from the ground. They also take part in medical experiments to determine how well their bodies are adjusting to living in microgravity for long periods of time.
Working on the space station also means ensuring the maintenance and health of the orbiting platform. Crew members are constantly checking support systems and cleaning filters, updating computer equipment: doing many of the things homeowners must do to ensure their largest investment stays in good shape. Similarly, the Mission Control Center constantly monitors the space station and sends messages each day through voice or email with new instructions or plans to assist the crew members in their daily routines.
In the early days, the job description of an astronaut was basically that of being an observer – someone who would view and document what was happening. It didn’t take long for NASA to understand that human interaction would be required. These astronauts work with pilots to conduct experiments, launch satellites, and maintain spacecraft and equipment. Their background can be in engineering, science, or medicine. They can also work as astronaut educators, inspiring students to consider joining the US space program.
These astronauts serve as space shuttle and international space station pilots and commanders. They are responsible for the crew, the mission, the mission success and the safety of the flight. The Johnson Space Center provides a number of simulators and facilities to prepare the astronauts for their work in space, such as a neutral buoyancy simulator, which simulates weightlessness on earth, and a 200′ long and 40′ deep pool where astronauts train for spacewalks underwater.
When in orbit, most of the time is spent in the craft or space station. At times, a spacewalk is required to make repairs, or to deploy a satellite, and the astronaut must wear a space suit, or an EMU (extravehicular mobility unit) for protection. Most missions last two to three weeks, but long duration missions may run as long as half a year. Training for long duration missions is very arduous and takes approximately two to three years.