Modifications to External Tank Stringers to Begin Tuesday

Science Technicians at NASA’s Kennedy Space Center in Florida will begin modifications to 34 support beams, called stringers, on space shuttle Discovery’s external fuel tank on Tuesday. Crews will fit pieces of metal, called radius blocks, over the tops of the stringers located at the external tank’s thrust panel area to increase the structural support of the stringers. The thrust panel areas are located at the attachment points between the tank and the solid rocket boosters, which see the most stress during the flight into orbit. The work is expected to take approximately one week. Teams currently are performing scans on all of the tank’s stringers using a backscatter device, which bounces radiation off the tank allowing engineers to see below the foam insulation.

Engineers at various NASA centers continue to analyze testing and imaging data. Managers will meet again Thursday to determine whether radius block modifications are needed on the remaining stringers. Repairs to four cracks on three stringers on the opposite side of the tank from Discovery that were discovered on Dec. 29 began Monday and are expected to be completed mid-week. The repairs are similar to repairs made on cracks found on two stringers after Discovery's Nov. 5 launch attempt. The next available launch date for Discovery's STS-133 mission to the International Space Station remains Feb. 3 at the opening of a window that extends through Feb. 10.