Shuttle astronaut in sleep restraint, 1980s.

The Space Shuttle, the world's first partially reusable launch vehicle, first flew on 12th April 1981 and has been used for all America's manned space misions ever since. It normally carries a crew of five to seven astronauts and can lift a payload of some 25,000 kilograms into low Earth orbit. The Orbiter and the solid fuel boosters are recovered and reused. Astronauts need to make use of slep restraints of this kind while aboard the Shuttle, as although the living quarters are presurised, the environment is weightles.