Space Shuttle Atlantis atop the mobile launcher platform and crawler-transporter makes its way to Launch Pad 39A.

Space Shuttle Atlantis, atop the mobile launcher platform and crawler-transporter, slowly makes its way to Launch Pad 39A, at left. First motion of the shuttle out of the Vehicle Assembly Building was at 8:19 a.m. The 3.4-mile trip to the pad along the crawlerway takes about 6 hours. The mission payload aboard Space Shuttle Atlantis is the S3/S4 integrated truss structure, along with a third set of solar arrays and batteries. The crew of six astronauts will install the truss to continue assembly of the International Space Station. Launch is targeted for March 15. Photo credit: NASA/Kim Shiflett