Space shuttle Discovery secured to a crawler-transporter moves at NASA's Kennedy Space Center.

Space shuttle Discovery, secured to a crawler-transporter, slowly moves away from Launch Pad 39A at NASA's Kennedy Space Center in Florida. The 3.4-mile trek, called rollback, to the Vehicle Assembly Building began at 10:48 p.m. and took about eight hours. Next, Discovery's external fuel tank will be examined and foam reapplied where 89 sensors were installed on the tank's aluminum skin for an instrumented tanking test on Dec. 17. The sensors were used to measure changes in the tank as super-cold propellants were pumped in and drained out. Data and analysis from the test will be used to determine what caused the tops of two, 21-foot-long support beams, called stringers, on the outside of the intertank to crack during fueling on Nov. 5.
Discovery's next launch opportunity to the International Space Station on the STS-133 mission is no earlier than Feb. 3, 2011. For more information on STS-133, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Frank Michaux