In the Vehicle Assembly Building at NASA's Kennedy Space Center, external tank No. 120 is lowered toward the mobile launcher platform in high bay 1 where it will be mated with the solid rocket boosters already there. The external tank-SRB stack is being prepared for the orbiter Discovery, which will be mated to the stack in the VAB in two weeks. Space Shuttle Discovery is targeted to launch Oct. 23 on mission STS-120 to the International Space Station. Photo credit: NASA/George Shelton