Foam applied to Discovery's fuel tank as repairs continue

NASA contractor technicians over the weekend sprayed a fresh layer of insulating foam over a section of Discovery's external tank where cracked support beams were replaced.

Protected by a specially constructed enclosure to maintain proper environmental conditions at launch pad 39A, the roughly inch-thick foam takes about four days to cure. Some detail work to trim and shape the foam will follow.

The foam application was the last major step in repairs to two cracked support beams called "stringers," located on the ridged intertank that sits between the internal liquid hydrogen and liquid oxygen propellant reservoirs, roughly at the level of the orbiter's nose.

The damage was discovered after surface foam over one of the stringers cracked during the fueling of Discovery on Nov. 5, a launch attempt that scrubbed because of a gas leak.

Teams have been using non-destructive scanning techniques to search for cracks in nearby stringers and areas where foam loss could be most damaging to the orbiter.

Engineers also have been examining the cracked stringers -- replaced with thicker "doublers" -- and studying the loads on those components during flight to help understand the impact of potential failures.

The analysis is part of the process to develop a flight rationale that would allow a launch from Kennedy Space Center between Dec. 3 and Dec. 6.

Shuttle program managers plan to hold a special meeting Wednesday to continue discussion. If the results are positive, a status briefing to announce a target launch date would be held next Monday.