NASA outlines fixes to shuttle external tanks

NASA aims to finish up fixes to shuttle external tanks in time to launch Discovery in May and then resume construction of the International Space Station with assembly missions in late August and mid-November.

Shuttle program managers on Tuesday detailed modifications NASA has made to six areas of the external tank since significant foam-shedding was noted on the agency's first post-Columbia mission last summer.

NASA had spent $205 million and two-and-a-half years making external tank modifications in the wake of the February 2003 Columbia accident, which was caused by a fatal foam insulation hit on the shuttle's left wing.

Despite the work, shuttle Discovery's external tank shed a large piece of foam that nearly struck that orbiter's right wing as the ship soared toward orbit on July 26.

Sixteen foam pieces -- including five large enough to cause catastrophic damage -- were detected during Discovery's launch.

Click here to see an internal NASA chart that shows the areas the foam came from and actions the agency has taken to mitigate foam shedding on future flights: etdebrismitigation.jpg