KENNEDY SPACE CENTER, FLA. -- Mauro Piermaria, the ESPERIA mission manager for ASI, the Italian Space Agency, answers questions from the media during a news briefing on the launch readiness of space shuttle mission STS-120. The STS-120 mission will be the 23rd shuttle flight to the International Space Station, delivering the Italian-built U.S. Node 2, called Harmony. The seven-member crew includes ESA astronaut Paolo Nespoli from Italy. The 14-day mission includes five spacewalks -- four by shuttle crew members and one by the station's Expedition 16 crew -- to install Harmony and move the P6 solar arrays to their permanent position and deploy them. Launch aboard space shuttle Discovery is planned for 11:38 a.m. EDT Oct. 23, and Discovery is scheduled to complete its mission and return home on Nov. 6. Photo credit: NASA/George Shelton KSC-07pd2914

The Space Shuttle program was the United States government's manned launch vehicle program from 1981 to 2011, administered by NASA and officially beginning in 1972. The Space Shuttle system—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). When its mission was complete, the orbiter would re-enter the Earth's atmosphere and lands as a glider. Although the concept had been explored since the late 1960s, the program formally commenced in 1972 and was the focus of NASA's manned operations after the final Apollo and Skylab flights in the mid-1970s. It started with the launch of the first shuttle Columbia on April 12, 1981, on STS-1. and finished with its last mission, STS-135 flown by Atlantis, in July 2011.