NASA will send an astronaut on an unprecedented in-flight shuttle repair mission to remove filler material protruding from heat-resistant tiles on Discovery's underbelly. Analysis showed that protrusions in two areas could produce excessive heat during re-entry and threaten the spacecraft, CNN reported. "It was prudent to take action so that we wouldn't have to worry about some of the worst consequences," said Wayne Hale, NASA's deputy shuttle program manager, at a news conference Monday evening. During Wednesday's planned space walk, astronaut Steve Robinson will be dangled from a robotic arm on the international space station and maneuvered to the bottom of Discovery to remove what NASA calls "gap fillers." Gap fillers are thin fabric stiffened with a ceramic material and used to plug gaps between the shuttle's tiles. One keeps tiles from vibrating against each other during liftoff and has no purpose for re-entry. The other is designed to prevent repeated overheating of a gap between two tiles. However, not having it in place during a single re-entry would still be "well within our safety margins," Hale said. If he cannot pull the gap fillers loose, Robinson will use a tool to cut them flush, or nearly flush, with the tiles, so they don't interfere with the shuttle's aerodynamic flow during re-entry to Earth's atmosphere, Hale said. Discovery can return safely without either of the gap fillers in place, Hale said.
