The external fuel tank and solid rocket boosters are already stacked on the mobile launcher platform.

In the upper levels of the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida, space shuttle Discovery is moved toward high bay 3 where the external fuel tank and solid rocket boosters are already stacked on the mobile launcher platform. Discovery will be lowered onto the platform and mated with the stack. After additional preparations are made, the shuttle will be rolled out to Launch Pad 39A for a targeted launch on Feb. 12. Discovery will carry the final starboard truss (S6) in the assembly of the International Space Station. Photo credit: NASA/Jack Pfaller