Bush's Vision for Space Exploration, use of the Space Shuttle was to be focused almost exclusively on completing assembly of the ISS, which was far behind schedule at that point. In 2004, according to President George W. space station evolved into the International Space Station and were formally initiated in 1983 by President Ronald Reagan, but the ISS suffered from long delays, design changes and cost over-runs and forced the service life of the Space Shuttle to be extended several times until 2011 when it was finally retired-serving twice as long than it was originally designed to do. The Shuttle was originally conceived of and presented to the public in 1972 as a 'Space Truck' which would, among other things, be used to build a United States space station in low Earth orbit during the 1980s and then be replaced by a new vehicle by the early 1990s. The program formally commenced in 1972, becoming the sole focus of NASA's human spaceflight operations after the Apollo, Skylab, and Apollo-Soyuz programs in 1975. Various shuttle concepts had been explored since the late 1960s. Original selling points on the shuttles were over 150 launches over a 15-year operational span with a 'launch per month' expected at the peak of the program, but extensive delays in the development of the International Space Station never created such a peak demand for frequent flights. Each vehicle was designed with a projected lifespan of 100 launches, or 10 years' operational life. The orbiter also recovered satellites and other payloads (e.g., from the ISS) from orbit and returned them to Earth, though its use in this capacity was rare. Its missions involved carrying large payloads to various orbits including the International Space Station (ISS), providing crew rotation for the space station, and performing service missions on the Hubble Space Telescope. The Shuttle is the only winged crewed spacecraft to have achieved orbit and landing, and the first reusable crewed space vehicle that has made multiple flights into orbit. When its mission was complete, the orbiter would reenter the Earth's atmosphere and land like a glider at either the Kennedy Space Center or Edwards Air Force Base. The Space Shuttle-composed of an orbiter launched with two reusable solid rocket boosters and a disposable external fuel tank-carried up to eight astronauts and up to 50,000 lb (23,000 kg) of payload into low Earth orbit (LEO). Its official name, Space Transportation System ( STS), was taken from a 1969 plan for a system of reusable spacecraft of which it was the only item funded for development. National Aeronautics and Space Administration (NASA), which accomplished routine transportation for Earth-to-orbit crew and cargo from 1981 to 2011. The Space Shuttle program was the fourth human spaceflight program carried out by the U.S.
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