Space Shuttle – Wikipedia, the free encyclopedia

This article is about the NASA Space Transportation System vehicle. For the associated program, see Space Shuttle program. For other shuttles and aerospace vehicles, see Spaceplane. Space Shuttle Discovery lifts off at the start of STS-120. Function Crewed orbital launch and reentry Manufacturer United Space Alliance Thiokol/Alliant Techsystems (SRBs) Lockheed Martin/Martin Marietta (ET) Boeing/Rockwell (orbiter) Country of origin United States of America Size Height 56.1 m (184.2 ft) Diameter 8.7 m (28.5 ft) Mass 2,030 t (4,470,000 lbm) Stages 2 Capacity Payload to LEO 24,400 kg (53,600 lb) Payload to GTO 3,810 kg (8,390 lb) Payload to Polar orbit 12,700 kg (28,000 lb) Payload to Landing 14,400 kg (32,000 lb[1]) Launch history Status Retired Launch sites LC-39, Kennedy Space Center SLC-6, Vandenberg AFB (unused) Total launches 135 Successes 133 launches and landings Failures 2 Challenger (launch failure), Columbia (re-entry failure) First flight April 12, 1981 Last flight July 21, 2011 Notable payloads Tracking and Data Relay Satellites Spacelab Hubble Space Telescope Galileo, Magellan, Ulysses Mir Docking Module ISS components Boosters (Stage 0) - Solid Rocket Boosters No. boosters 2 Engines 2 solid Thrust 12.5 MN each, sea level liftoff (2,800,000 lbf) Specific impulse 269 seconds (2.64km/s) Burn time 124 s Fuel Solid (Ammonium perchlorate composite propellant) First stage - Orbiter plus External Tank Engines 3 SSMEs located on Orbiter Thrust 5.25MN (1,180,000lbf) total, sea level liftoff [2] Specific impulse 455 seconds (4.46km/s) Burn time 480 s Fuel LOX/LH2

The Space Shuttle was a partially reusable low Earth orbital spacecraft system operated by the U.S. National Aeronautics and Space Administration (NASA). Its official program name was Space Transportation System, taken from a 1969 plan for a system of reusable spacecraft of which it was the only item funded for development.[3] The first of four orbital test flights occurred in 1981, leading to operational flights beginning in 1982. They were used on a total of 135 missions from 1981 to 2011, launched from the Kennedy Space Center (KSC) in Florida. Operational missions launched numerous satellites, interplanetary probes, and the Hubble Space Telescope (HST); conducted science experiments in orbit; and participated in construction and servicing of the International Space Station. The Shuttle fleet totaled 1322 days, 19 hours, 21 minutes and 23 seconds during missions.[4]

Shuttle components included the Orbiter Vehicle (OV), a pair of recoverable solid rocket boosters (SRBs), and the expendable external tank (ET) containing liquid hydrogen and liquid oxygen. The Shuttle was launched vertically, like a conventional rocket, with the two SRBs operating in parallel with the OV's three main engines, which were fueled from the ET. The SRBs were jettisoned before the vehicle reached orbit, and the ET was jettisoned just before orbit insertion, which used the orbiter's two Orbital Maneuvering System (OMS) engines. At the conclusion of the mission, the orbiter fired its OMS to de-orbit and re-enter the atmosphere. The orbiter glided to a runway landing on Rogers Dry Lake at Edwards Air Force Base in California or at the Shuttle Landing Facility at the KSC. After the landings at Edwards, the orbiter was flown back to KSC on the Shuttle Carrier Aircraft, a specially modified Boeing 747.

The first orbiter, Enterprise, was built for Approach and Landing Tests and had no orbital capability. Four fully operational orbiters were initially built: Columbia, Challenger, Discovery, and Atlantis. Of these, Challenger and Columbia were destroyed in mission accidents in 1986 and 2003 respectively, in which a total of fourteen astronauts were killed. A fifth operational orbiter, Endeavour, was built in 1991 to replace Challenger. The Space Shuttle was retired from service upon the conclusion of Atlantis's final flight on July 21, 2011.

The Space Shuttle was a partially reusable[5]human spaceflight vehicle capable of reaching low Earth orbit, commissioned and operated by the US National Aeronautics and Space Administration (NASA) from 1981 to 2011. It resulted from shuttle design studies conducted by NASA and the US Air Force in the 1960s and was first proposed for development as part of an ambitious second-generation Space Transportation System (STS) of space vehicles to follow the Apollo program in a September 1969 report of a Space Task Group headed by Vice President Spiro Agnew to President Richard Nixon. Post-Apollo NASA budgeting realities impelled Nixon to withhold support of all system components except the Shuttle, to which NASA applied the STS name.[3]

The vehicle consisted of a spaceplane for orbit and re-entry, fueled by expendable liquid hydrogen and liquid oxygen tanks, with reusable strap-on solid booster rockets. The first of four orbital test flights occurred in 1981, leading to operational flights beginning in 1982, all launched from the Kennedy Space Center, Florida. The system was retired from service in 2011 after 135 missions,[6] with Atlantis making the final launch of the three-decade Shuttle program on July 8, 2011.[7] The program ended after Atlantis landed at the Kennedy Space Center on July 21, 2011. Major missions included launching numerous satellites and interplanetary probes,[8] conducting space science experiments, and servicing and construction of space stations. The first orbiter vehicle, named Enterprise, was built for the initial Approach and Landing Tests phase and lacked engines, heat shielding, and other equipment necessary for orbital flight.[9] A total of five operational orbiters were built, and of these, two were destroyed in accidents.

It was used for orbital space missions by NASA, the US Department of Defense, the European Space Agency, Japan, and Germany.[10][11] The United States funded Shuttle development and operations except for the Spacelab modules used on D1 and D2sponsored by Germany.[10][12][13][14][15]SL-J was partially funded by Japan.[11]

At launch, it consisted of the "stack", including the dark orange external tank (ET);[16][17] two white, slender solid rocket boosters (SRBs); and the Orbiter Vehicle, which contained the crew and payload. Some payloads were launched into higher orbits with either of two different upper stages developed for the STS (single-stage Payload Assist Module or two-stage Inertial Upper Stage). The Space Shuttle was stacked in the Vehicle Assembly Building, and the stack mounted on a mobile launch platform held down by four frangible nuts[18] on each SRB, which were detonated at launch.[19]

The Shuttle stack launched vertically like a conventional rocket. It lifted off under the power of its two SRBs and three main engines, which were fueled by liquid hydrogen and liquid oxygen from the ET. The Space Shuttle had a two-stage ascent. The SRBs provided additional thrust during liftoff and first-stage flight. About two minutes after liftoff, frangible nuts were fired, releasing the SRBs, which then parachuted into the ocean, to be retrieved by ships for refurbishment and reuse. The orbiter and ET continued to ascend on an increasingly horizontal flight path under power from its main engines. Upon reaching 17,500mph (7.8km/s), necessary for low Earth orbit, the main engines were shut down. The ET, attached by two frangible nuts[20] was then jettisoned to burn up in the atmosphere.[21] After jettisoning the external tank, the orbital maneuvering system (OMS) engines were used to adjust the orbit. The orbiter carried astronauts and payloads such as satellites or space station parts into low Earth orbit, the Earth's upper atmosphere or thermosphere.[22] Usually, five to seven crew members rode in the orbiter. Two crew members, the commander and pilot, were sufficient for a minimal flight, as in the first four "test" flights, STS-1 through STS-4. The typical payload capacity was about 50,045 pounds (22,700kg) but could be increased depending on the choice of launch configuration. The orbiter carried its payload in a large cargo bay with doors that opened along the length of its top, a feature which made the Space Shuttle unique among spacecraft. This feature made possible the deployment of large satellites such as the Hubble Space Telescope and also the capture and return of large payloads back to Earth.

When the orbiter's space mission was complete, it fired its OMS thrusters to drop out of orbit and re-enter the lower atmosphere.[22] During descent, the orbiter passed through different layers of the atmosphere and decelerated from hypersonic speed primarily by aerobraking. In the lower atmosphere and landing phase, it was more like a glider but with reaction control system (RCS) thrusters and fly-by-wire-controlled hydraulically actuated flight surfaces controlling its descent. It landed on a long runway as a spaceplane. The aerodynamic shape was a compromise between the demands of radically different speeds and air pressures during re-entry, hypersonic flight, and subsonic atmospheric flight. As a result, the orbiter had a relatively high sink rate at low altitudes, and it transitioned during re-entry from using RCS thrusters at very high altitudes to flight surfaces in the lower atmosphere.