KENNEDY SPACE CENTER, FLA. -- The super lightweight ablator, or SLA, cork insulation has been removed from the external tank and a United Space Alliance external tank technician sands off the residue from the LO2 feed line bracket. The BX265 foam insulation will later be reapplied without the SLA. The tank is scheduled to fly on Space Shuttle Discovery in October 2007 on mission STS-120. Discovery's crew will add the module Harmony that will serve as a port for installing additional international laboratories. Harmony will be the first expansion of the living and working space on the complex since the Russian Pirs airlock was installed in 2001. The mission also will move the first set of solar arrays installed on the station to a permanent location on the complex and redeploy them. Photo credit: NASA/Jim Grossmann KSC-07pd2371

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.