The Space Shuttle is the first orbital spacecraft designed for reuse. It carries different 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. (From Wikipedia)
Each Shuttle was designed for a projected lifespan of 100 launches or ten years of operational life, although this was later extended. The person in charge of designing 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 commercial and classified satellites, and have the cross-range recovery range to meet the requirement for classified USAF missions for a once-around abort from a launch to a polar orbit.
Factors involved in opting for 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 airworthy Space Shuttle orbiters have been built; the first, Enterprise, was not built for orbital space flight, and was used only for testing purposes. Five space-worthy orbiters were built: Columbia, Challenger, Discovery, Atlantis, and Endeavour.
Enterprise was originally intended to be made fully space-worthy after use for the approach and landing test (ALT) program, but it was found more economical to upgrade the structural test article STA-099 into orbiter Challenger (OV-099).
Challenger disintegrated 73 seconds after launch in 1986 STS-51-L, and Endeavour was built as a replacement from structural spare components.
Columbia broke apart during re-entry in 2003 STS-107. Building Space Shuttle Endeavour cost about US$1.7 billion. One Space Shuttle launch costs around $450 million.Each Space Shuttle is a reusable launch system that is composed of three main assemblies: the reusable Orbiter Vehicle (OV), the external tank (ET), and the two reusable solid rocket boosters (SRBs).
The tank and boosters are jettisoned during ascent; only the orbiter enters 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. The SRBs parachute back to earth, where they are collected from the ocean and refilled for another use.
Retirement and legacy NASA’s current plans call for the Space Shuttle to be retired from service in 2011, after nearly 30 years of service. Under the current plans, Atlantis will be the first of NASA’s three remaining operational Space Shuttles to be retired as the program winds down.
To fill the void left by the Shuttle’s retirement, a new spacecraft is being developed to ferry not only passengers and cargo to the ISS but also to travel beyond Earth orbit to the Moon and Mars. Originally called the Crew Exploration Vehicle, the concept has evolved into the Orion spacecraft and the project named Project Constellation.
President Obama’s administration has proposed eliminating public funds for the Constellation program and shifting the burden for developing a replacement low-orbit service to private corporations.
Until another launch vehicle is ready, crews would travel to and from the International Space Station aboard Russian Soyuz spacecraft or possibly a future American commercial spacecraft. However, President Obama’s plan must be approved by the United States Congress, and counter-proposals are currently being considered by Congress, including the potential extension of the Space Shuttle program for an additional five years while a replacement can be developed.
The Shuttle Discovery has already been promised to the Smithsonian Institution’s National Air and Space Museum, and Atlantis, Endeavour, and Enterprise are planned to be sold to other education institutions or museums for $28.8 million each.
Michael Suffredini of the ISS program has said that one additional trip will be needed in 2011 to deliver parts to the International Space Station.The Space Shuttle was originally to be retired in late 2010, but has been extended until February 2011.
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