KENNEDY SPACE CENTER, Fla. -- Practicing emergency egress from Launch Pad 39A, STS-118 Commander Scott Kelly (left) reaches for the pull lever of the slidewire basket. Behind him is Pilot Charlie Hobaugh. At upper left in another basket is Mission Specialist Rick Mastracchio. Other crew members are Mission Specialists Dave Williams, Barbara R. Morgan, Tracy Caldwell and Alvin Drew. Morgan joined NASA's Teacher in Space program in 1985 and was selected as an astronaut in 1998. Williams represents the Canadian Space Agency. The STS-118 mission on Space Shuttle Endeavour is the 22nd flight to the International Space Station and will carry a payload including the S5 truss, a SPACEHAB module and external stowage platform 3. STS-118 is targeted for launch on Aug. 7. NASA/George Shelton KSC-07pd2001

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.