A space shuttle is a reusable spacecraft that:
takes off as a rocket,
orbits the Earth as a spacecraft,
lands like an aeroplane.
Space shuttles are reusable spacecraft. To get through Earth's atmosphere, the shuttle is attached to a rocket and launched from a launch pad. Two rocket boosters provide 70 per cent of the thrust needed to lift the space shuttle off the pad, the rest of the thrust comes from the shuttle's engines.
About 2 minutes after the launch time, when the shuttle has reached an altitude of about 45 kilometres, the rocket boosters separate from the shuttle and parachute into the ocean, from which they can be recovered, and reused. The shuttle's main engines keep it going, using fuel from an external fuel tank.
About 8 minutes after the launch, the fuel tank falls away and burns up in the atmosphere. The shuttle's main engines shut down and smaller engines move the shuttle into orbit.
On returning to Earth, the main engines fire and take the shuttle back into the Earth's atmosphere and then are shut down. During re-entry into the Earth's atmosphere, the space shuttle passes through extreme heat. A heat protection system covering the space shuttle protects it from the high temperatures. This covering doesn't burn off and is re-usable.
The unpowered space shuttle glides to earth and lands on a runway like an aeroplane. Its brakes stop it on the runway. Then the shuttle is towed away to be made ready for its next flight.
After 30 years of spaceflight, NASA has retired its shuttles.
The last American space shuttle flight was on 21st July 2011. The old shuttles are on display in various places across the USA.
NASA continues its work in designing and developing new systems, machines, and ways of sending humans into outer space on longer missions.
The International Space Station (ISS) is currently NASA's only activity in human spaceflight. Fully staffed with a crew of six, astronauts continue to live and work there 365 days a year. The American part of the space station is a laboratory, and is used for scientific research.
Russian shuttle spacecraft now service the ISS, taking supplies and astronauts there.