NASA To Examine Signs Of Degradation On Discovery RCC Tiles

Safety Team Recommends Replacement; Launch Could Be Delayed

NASA will examine a handful of reinforced carbon-carbon (RCC) heating tiles on the wings of the space shuttle Discovery, now at the launch pad in anticipation of an October 23 launch, to determine if the tiles should be replaced.

The Associated Press reports three of the 44 reinforced tiles that line the edges of Discovery's wings show signs of degradation in their outer coating.

The issue has come up before, the space agency says; thermography inspections of the affected tiles have shown no internal defects in the tiles, which gives NASA scientists little clue as to what may be causing the degradation.

Discovery has flown at least twice with the tiles in their present state, according to NASA, with no apparent problems. Still, on Wednesday the NASA Engineering and Safety Center (NESC) recommended replacement of three of the tiles.

Replacement of the tiles would require a trip back to the Vehicle Assembly Building for Discovery... potentially adding weeks to the timetable for launch.

NASA managers wrapped up two days of meetings Wednesday, ahead of next week's Flight Readiness Review. That meeting is planned for October 16, and its unlikely a decision on whether to replace the tiles will be made prior to then.

The issue of whether to replace the tiles is a thorny one for NASA, in light of the 2003 loss of Columbia. A breach of several RCC tiles on the leading edge of that orbiter's left wing -- caused by a chunk of insulating foam that struck the tiles during launch -- led to the shuttle's destruction during reentry.