Significant changes should be made before the space shuttle's next launch to eliminate sporadic erosion in the heat-resistant material that protects the nozzle of its booster rocket, says a 240-page internal report being reviewed by the National Aeronautics and Space Administration.
The report said tests show that the material--a carbon-and-resin liner slightly more than an inch thick inside the nozzle's aft exit cone--has on several occasions suffered "fractures . . . so numerous, so large, so closely spaced and so extensive that the integrity of the entire (cone) came into question."
Cone Directs Exhaust
The report enumerates steps to enhance the durability of the material, which shields the cone from the hot propellant exhaust generated at launch. The cone directs exhaust and helps the rocket gain enough thrust to ensure liftoff.
Nowhere does the report describe the problem as potentially catastrophic. Top NASA officials say initial concern over the erosion has been tempered by two recent tests, which resulted in the kind of limited erosion considered normal.