A backscatter device continues to give engineers data on the region of Discovery's external fuel tank while it is in the Vehicle Assembly Building.

A backscatter device continues to give engineers data on the intertank region of space shuttle Discovery's external fuel tank while it is in the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida. Engineers at various NASA centers are analyzing, testing and imaging the intertank's support beams, called stringers, to make sure the tank is structurally sound for flight.

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/Jack Pfaller