Space Shuttle
Space Shuttle Discovery launches at the start of STS-120.
Fact sheet
Function	Manned partially re-usable launch and reentry system
Manufacturer	United Space Alliance: Thiokol/Boeing (SRBs) Lockheed Martin (Martin Marietta) - (ET) Rockwell International (orbiter)
Country of origin	United States of America
Size
Height	56.1 m (184 ft (56 m))
Diameter	8.7 m (28.5 ft (8.7 m))
Mass	2,029,203 kg (4,474,574 lb)
Stages	2
Capacity
Payload to LEO	24,400 kg (53,700 lb)
Payload to GTO	3,810 kg (8,390 lb)
Launch History
Status	Active
Launch sites	LC-39, Kennedy Space Center SLC-6, Vandenberg AFB (unused)
Total launches	121
Successes	119
Failures	2
Maiden flight	April 12, 1981
Notable payloads	International Space Station components Hubble Space Telescope Galileo Magellan Chandra X-ray Observatory Compton Gamma Ray Observatory
Boosters (Stage 0) - Solid Rocket Boosters
No boosters	2
Engines	1 solid
Thrust	2,800,000 lbf each, sea level liftoff (12.5 MN)
Specific impulse	269 s
Burn time	124 s
Fuel	solid
First Stage - External Tank
Engines	(none) (3 SSMEs located on Orbiter)
Thrust	1,180,000 lb (540,000 kg)f combined total, sea level liftoff (5.25 MN)
Specific impulse	455 s
Burn time	480 s
Fuel	LOX/LH2
Second Stage - Orbiter
Engines	2 OME
Thrust	12,000 lbf combined total vacuum thrust (53 kN)
Specific impulse	316 s
Burn time	1250 s
Fuel	MMH/N2O4

Space Shuttle program insignia

NASA's Space Shuttle, officially called the Space Transportation System (STS), is the spacecraft currently used by the United States government for its human spaceflight missions. At launch, it consists of a rust-colored external tank (ET), two white, slender Solid Rocket Boosters (SRBs), and the orbiter, a winged spaceplane which is the space shuttle in the narrow sense.

The orbiter carries astronauts and payload such as satellites or space station parts into low earth orbit, into the Earth's upper atmosphere or thermosphere.^[1] Usually, five to seven crew members ride in the orbiter. The payload capacity is 50,000 lb (22,700 kg). When the orbiter's mission is complete it fires its Orbital Maneuvering System (OMS) thrusters to drop out of orbit and re-enters the lower atmosphere.^[1] During the descent and landing, the shuttle orbiter acts as a glider, and makes a completely unpowered ("dead stick") landing.

The shuttle is the first orbital spacecraft designed for partial reusability. It carries payloads to low Earth orbit, provides crew rotation for the International Space Station (ISS), and performs servicing missions. The orbiter can also recover satellites and other payloads from orbit and return them to Earth, but this capacity has not been used often. However, it has been used to return large payloads from the ISS to Earth, as the Russian Soyuz spacecraft has limited capacity for return payloads. Each Shuttle was designed for a projected lifespan of 100 launches or 10 years' operational life. The man responsible for the design of the STS was Maxime Faget, who had also overseen the Mercury, Gemini and Apollo spacecraft designs. The crucial factor in the size and shape of the Shuttle Orbiter was the requirement that it be able to accommodate the largest planned spy satellites, and have the cross-range recovery range to meet classified USAF missions requirement for a one-around abort for a polar launch. Factors involved in opting for 'reusable' solid rockets and an expendable fuel tank included the desire of the Pentagon to obtain a high-capacity payload vehicle for satellite deployment, and the desire of the Nixon administration to reduce the costs of space exploration by developing a spacecraft with reusable components.

Six air-worthy shuttles have been built; the first orbiter, Enterprise, was not built for space flight, and was used only for testing purposes. Five space-worthy orbiters were built: Columbia, Challenger, Discovery, Atlantis, and Endeavour. Challenger disintegrated 73 seconds after launch in 1986, and Endeavour was built as a replacement. Columbia broke apart during re-entry in 2003.

First launched in 1981, NASA has announced that the Space Shuttle would be retired in 2010, and from 2014 on, would be replaced by Orion, a new vehicle that is designed to take humans to the Moon and beyond along with its partner rockets, the Ares I and Ares V Rockets; however, since Orion is meant primarily for manned space flights, ESA's Automated Transfer Vehicle, with its 7,667 kg payload, has been suggested as an alternative for tasks like supplying space stations.

Each Space Shuttle is a partially reusable launch system that is composed of three main assemblies: the reusable Orbiter Vehicle (OV), the expendable external tank (ET), and the two partially-reusable solid rocket boosters (SRBs). The tank and boosters are jettisoned during ascent; only the orbiter goes into orbit. The vehicle is launched vertically like a conventional rocket, and the orbiter glides to a horizontal landing, after which it is refurbished for reuse.

At times, the orbiter itself is referred to as the space shuttle. Technically, this is a misnomer, as the actual "Space Transportation System" (space shuttle) is the combination of the orbiter, the external tank (ET), and the two partially-reusable solid rocket boosters. Combined, these are referred to as the "Stack".