Speed Brake Gears Were Installed Backward   

As if NASA needed any more controversy with its shuttle fleet program, the agency just released findings that would make any astronaut cringe. NASA said it will replace braking mechanisms on all its space shuttles after discovering some of the gears were installed backward. Shuttle program manager Bill Parsons said Monday he has launched an investigation into why the rudder speed brake gears — all old original parts in the shuttle tails — were never inspected in more than two decades of flight. If one of the improperly installed gears had been in a high-stress position, it probably would have led to the destruction of the spacecraft at touchdown, he said.

"Bottom line is, it was not good," Parsons said.

The reversed gears found recently in Discovery were in the least stress-prone position and never failed. But one of the replacement gears — a spare set that was also installed backward — would have ended up in a much more high-stress location in the tail. The installation problem surfaced late last year and prompted NASA to delay the next shuttle flight from fall 2004 to spring 2005.

All the rudder speed brake gears in NASA's inventory — dating as far back as the 1970s — are being X-rayed to see whether they were properly built, and to look for rust and microcracks, already spotted on some gears. Parsons said new or refurbished gears should be installed in time for shuttle flights to resume next March, after a two-year grounding following the Columbia tragedy.

"Because of the way these gears go together, you can actually make a mistake and put them in incorrectly, and there was not a good process back in the timeframe" to catch mistakes, Parsons said. He said the maker of the rudder speed brake mechanisms, Hamilton Sundstrand in Rockford (IL), now has better quality control.

At the same time, NASA is inspecting the plumbing in each of its three remaining shuttles. The hoses in question are also original shuttle parts and some are starting to leak, Parsons said. Parsons said engineers are making good progress on the inspection booms and wing-repair kits that will be required on all future shuttle flights.

"As we deal with aging vehicle kind of issues, we will find other things along these lines as well, I'm sure," he said

While Discovery is scheduled to fly first, the Atlantis must be ready to launch quickly and assist the Discovery via the international space station, if a problem were to arise. This is part of a new mandate enacted as a result of the Columbia accident investigation.

Columbia was destroyed and its seven astronauts were killed during re-entry last year because of a hole in the left wing caused by a piece of insulating foam that broke free at liftoff.

FMI: http://spaceflight.nasa.gov