More than 350 Astronauts have traveled into space: 26 on missions to the moon and the rest in orbit around earth. For journeying into space, astronauts must be physically and mentally fit. They must also be trained to prepare them for living and working in the hostile environment of space.
When they work outside the spacecraft, they need to wear a suit that keeps their body at the correct temperature and protects them from fast moving micrometeoroids. The suit must also provide oxygen for breathing and be pressurized because there is no air or atmospheric pressure in space.
To fly free from the spacecraft as astronaut wears powered backpack, the Manned Maneuvering Unit (MMU). Mini nitrogen thrusters, operated from arm rests, propel the astronaut at about 20 m/s (65 ft/S).
The first person to fly into space was a Russian, Yuri Gagarin (1934 – 68). His flight on 12 April 1961 took him once around the earth and lasted 108 minutes. No one knew how the space flight would affect a human, so Gagarin’s spacecraft, Vostk I, was controlled from the ground.
Living in space:
Daily life for an astronaut includes all the usual things, such as breathing, eating, sleeping and going to the bathroom. The big difference, however, is living in weightless conditions. Sleeping astronauts float around the spacecraft unless tethered down, and using the toilet has to be carefully controlled. Astronauts need daily exercise to keep fit in the weightless conditions of space.
Meals on the Space Shuttle are prepared from 70 different foods and 20 drinks. The meal tray is strapped down and the food eaten with the hand or cutlery. Liquids are sucked from cartons or tubes.
Astronauts outside the spacecraft Go to the toilet in their spacesuit, where the waste materials are collected. Inside the craft, they use a space toilet, making sure they are firmly strapped to the seat. The waste is sucked away by the toilet and collected in a secure unit.
Staying in one place is a spacecraft can be problem. Suction-sup shoes allow astronauts to get a better grip.
Working in Space:
Each member of a space crew has specific tasks. These may include flying the craft, releasing a satellite into orbit and testing new equipment. The weightless conditions of space mean that astronauts can also perform experiments not possible on earth.
Once a satellite is in space, it is left to work on its own. But occasionally one needs repairing. The cargo bay of the space shuttle is equipped with a robotic arm, which specially trained astronauts use to recover the satellite. They can then repair the satellite and release it back into orbit.
Astronauts have carried out many experiments in space. These include observing how living things such as bees are affected by weightlessness.
Most astronauts spend only a few days in space, but some stay for months. Russian cosmonaut Sergei Avdeyev holds the overall endurance record (748 days). Russian Valeri Poliakov holds the record for the longest single stay of 438 days.
Humans are not the only space travelers. Early one included dogs, cats, and mice. Animals are no longer sent into space alone. But flies, frogs and tadpoles occasionally accompany human astronauts.