Atop the massive mobile launcher platform and crawler-transporter, Space Shuttle Atlantis begins rolling through the open door of the Vehicle Assembly Building for the journey to Launch Pad 39A. First motion was at 8:19 a.m. In front of each of Atlantis' wings are the tail masts, which provide several umbilical connections to the orbiter, including a liquid-oxygen line through one and a liquid-hydrogen line through another. The 3.4-mile trip to the pad along the crawlerway will take 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.