Atlantis atop a Shuttle Carrier Aircraft or SCA is towed from the runway at NASA's Kennedy Space Center.

Against a setting sun, space shuttle Atlantis, atop a Shuttle Carrier Aircraft, or SCA, is towed from the runway at NASA's Kennedy Space Center in Florida. The SCA is a modified Boeing 747 jetliner. Atlantis returned from California atop the SCA after its May 24 landing at Edwards Air Force Base, concluding mission STS-125. The ferry flight from Edwards Air Force Base began June 1. Atlantis' next assignment is the STS-129 mission, targeted to launch in November 2009. Photo credit: NASA/Jack Pfaller