Inside the Vehicle Assembly Building, the external tank is mated to its twin solid rocket boosters on the mobile launch platform in high bay 3 for mission STS-116. The gigantic, rust-colored external tank is the largest element of the Space Shuttle system at 27.6-feet wide and 154-feet tall. STS-116 will be mission No. 20 to the International Space Station and construction flight 12A.1. The mission payload is the SPACEHAB module, the P5 integrated truss structure and other key components. Launch is scheduled for no earlier than Dec. 7. Photo credit: NASA/Jack Pfaller