Space Shuttle

The U.S. National Aeronautics and Space Administration's (NASA's) so-called space shuttle system is a small fleet of reusable spacecraft designed to transport people and cargo from Earth to low Earth orbit and back. In the 21st century, its primary function has been to build and service the International Space Station (ISS). What is typically referred to as a space shuttle consists of an orbiter (technically, an orbiter vehicle, or OV), a pair of solid rocket boosters (SRBs), and an external liquid fuel tank (ET). Each orbiter is powered by three liquid-fueled space shuttle main engines (SSMEs) that are integrated into the vehicle. From its inception, the U.S. space shuttle program has been the subject of considerable media coverage, in both good times and bad.

NASA's space shuttle fleet has included up to five orbiters, first launched in the following order between 1981 and 1992: Columbia (OV-102, 1981), Challenger (OV-099, 1983), Discovery (OV-103, 1984), Atlantis (OV-104, 1985), and Endeavour (OV-105, 1992). Challenger was destroyed in January 1986 during launch. Columbia was destroyed on returning to Earth in February 2003. NASA's first piloted space shuttle mission had a crew of two. Crews now typically include seven people.

Officially, NASA's shuttle system is referred to as the Space Transportation System (STS). Over time, inside and outside NASA, the fleet and its individual orbiters became known simply as the space shuttle. Shuttle mission designations all start with “STS” followed by a number. For example, the last mission of the orbiter Challenger was [Page 827]designated STS-51, and the last mission of Columbia was STS-107.

In developing the space shuttle system, NASA first built a “test article” orbiter named Enterprise for ground and flight demonstrations. Enterprise was not intended for launching. It now resides in the National Air and Space Museum's Steven F. Udvar-Hazy Center in Chantilly, Virginia. After the Challenger and the Columbia orbiters were destroyed in accidents in 1986 and 2001, respectively, NASA had three remaining operational orbiters, named Atlantis, Discovery, and Endeavour, and no plans to build any new ones.

NASA's last three scheduled space shuttle missions, all dedicated to servicing the ISS, are designated STS-130, 131, and 132 and scheduled to launch in 2010. STS-132 will be NASA's 34th shuttle mission to the ISS. Plans for operating the space shuttle system beyond 2010 are uncertain. The United States has no other means of transporting humans into space, and NASA has contracted with Russia's space agency for astronaut transportation until it can complete another human-spaceflight system.

NASA's astronaut corps, which provides crews for space shuttle missions, is based at the agency's Johnson Space Center (JSC) in Houston, Texas. Depending on the mission, shuttle crews have included Russian cosmonauts and representatives of several other nations and space agencies, as well as a few corporate “payload specialists.” Shuttle crews train for missions primarily at JSC and at NASA's Kennedy Space Center (KSC) in Florida, although some missions require cross-training at Russia's Star City cosmonaut complex.

The United Space Alliance, a limited liability company equally owned by the Boeing Company and Lockheed Martin Corporation, operates the space shuttle system under contract to NASA. All shuttle missions launch from KSC, which has a launch complex including two shuttle launch pads (LC-39A and LC-39B), a Vehicle Assembly Building (VAB), an Orbiter Processing Facility (OPF), and a “crawler” vehicle designed to carry orbiters from the VAB to the launch pads.

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