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.