A re-usable crewed launch vehicle. The first-generation US shuttle launched in April 1981, managed by NASA's Johnson and Marshall Space Centers. The first Soviet shuttle, Buran, was launched in November 1988 for a single test flight without crew, using the Energiya booster. The European Space Agency shuttle Hermes programme was cancelled after several years' development.

The US shuttle carries up to seven crew, and is capable of launching a 24 400-kg / 53 700-lb payload into low Earth orbit; missions are up to 14 days' duration. It comprises a delta-winged lifting body orbiter with main engines, a jettisonable external fuel tank, and two auxiliary solid rocket boosters. The fleet comprises four vehicles: Columbia, Discovery, Atlantis, and Endeavour.

It has been successfully used to launch numerous science and applications satellites and on-board experiments, to carry the Spacelab module, and to retrieve spacecraft from orbit. The Challengerexplosion on the 25th flight (28 Jan 1986) 73 sec after launch caused the loss of the crew. The first reflight took place in September 1988, and a replacement orbiter, Endeavour,became operational in May 1992.

The Space Shuttle is a reusable rocket-launched vehicle designed to transport people and cargo between Earth and orbiting spacecraft, and then to return to the Earth's surface by gliding down and landing on a runway. A Space Shuttle consists of a reusable delta-winged spaceplane, called an orbiter; two solid-propellant booster rockets, which are recovered and also reused; and an expendable tank containing liquid propellant for the orbiter�s three main engines. Only the orbiters have names, and an orbiter alone is not a full Space Shuttle.

The Shuttle was selected in the early 1970s as the principal space launcher and carrier vehicle to be developed by the National Aeronautics and Space Administration (NASA). Planned as a replacement for expensive, expendable booster rockets, it would complete NASA's new Space Transportation System (STS). The program finally got under way in the early 1980s.

The shuttle takes off from the Kennedy Space Center in Florida and usually lands at Kennedy. It is carried into space on the back of a powerful liquid-fuel rocket, with a second pair of solid-rocket boosters strapped onto the sides. The shuttle lands like a conventional aircraft, though it depends heavily on sophisticated computers, software, and skilled pilots. There is little room for error and no second chances; at 10,000 feet high and 25 miles from touchdown, it must already be in the glide slope and centred precisely on the runway to make a proper landing.

The Space Shuttle was developed by the National Aeronautics and Space Administration. NASAcoordinates and manages the Space Transportation System (NASA's name for the overall Shuttle program), including intergovernmental agency requirements and international and joint projects. NASA also oversees the launch and space flight requirements for civilian and commercial use.

The first shuttle was Columbia, launched on April 12, 1981. It broke up shortly before a scheduled landing, on February 1st, 2003.

The Space Shuttle system consists of four primary elements:

• a winged orbiter that carries both crew and cargo;
• three Space Shuttle main engines;
• an external tank containing liquid hydrogen (fuel) and liquid oxygen (oxidizer) for the orbiter's three main rocket engines; and
• a pair of large, solid-propellant, strap-on booster rockets (Solid Rocket Boosters (SRBs))

At lift-off, the entire system weighs 4,400,000 pounds (2,000,000 kilograms) and stands 184 feet (56 metres) high. During launch the boosters and the orbiter's main engines fire together, producing 7,000,000 pounds (31,000,000 newtons) of thrust.

After two minutes of flight a Space Shuttle reaches an altitude of 32 miles (48 kilometers) and the boosters have burned all their propellant. They then detach and parachute into the ocean. Two waiting ships recover them, for refurbishment and reuse on later missions. After the orbiter has exhausted the propellants in the external tank upon attaining 99 percent orbital velocity, it releases the structure, which disintegrates while falling through the atmosphere.

The orbiter and external tank continue on toward Earth orbit. When the orbiter�s main engines cut off, just before achieving orbit, the external tank is jettisoned, to re-enter the atmosphere and break up over a remote ocean area. On most missions the orbiter continues to coast until it reaches the other side of the Earth from where the external tank was discarded. The on-board orbital maneuvering engines are then fired to place the vehicle in a near-circular low-Earth orbit. Most operational missions last from four to seven days, though longer ones are sometimes required.

The first Space Shuttle lifted off from Pad A on Launch Complex 39, Kennedy Space Center, on April 12, 1981. After a two-day, test-flight mission that verified the ability of the Orbiter Columbia to function in space, it landed at Edwards AFB in California. The vehicle was piloted by John Young and Robert Crippen. The STS-1 mission marked the first time that a new space vehicle carried a crew on its initial flight.

An assembled Space Shuttle is approximately 184 feet (56 meters) long, 76 feet (23 meters) high to the tip of the orbiter�s vertical tail, and 78 feet (24 meters) wide, measuring across the orbiter�s wingtips. Liftoff weight is usually about 4,500,000 pounds (2,041,200 kilograms).

An orbiter�s three liquid fueled engines -- drawing propellants from the external tank -- and the two solid-propellant rocket boosters burn simultaneously for the first two minutes. Together, they produce about 7.3 million pounds (32.4 million newtons) of thrust at liftoff.

When the mission has been completed, the orbiter re-enters the atmosphere and returns to Earth, gliding to an unpowered landing at either KSC or Edwards AFB.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Space_Shuttle_program"