This
story is Chapter 6 in an 11-part series by Florida Today.
Michael Brieden bore bad
news. Sixteen months after the Columbia accident, Brieden stood in a conference
center meeting room, a corporate amphitheater of sorts, in Ogden, Utah.
Surrounding him that day:
Heavy hitters from NASA headquarters, the American aerospace industry, agency
field centers, an independent oversight group and the Astronaut Office.
Brieden, then lead engineer
on a project to develop wing panel repairs, was center stage. He got right to
the point.
There was no chance NASA,
by return to flight, could develop a way to repair the type of severe damage
that doomed Columbia and its crew.
"I just laid the dirt
on the table, and that boiled up a conversation really quick," said
Brieden, 42. "So we had a big, energetic discussion on how come Brieden
couldn't provide a good wrap in time for STS-114. And that just led me through
my charts."
His PowerPoint presentation
covered all the facts.
Engineers had worked
overtime on a promising concept: rigid composite carbon over-wraps that could
be bolted onto wing panels. They performed as protective skins that could cover
holes as big as a large pizza. But the earliest delivery date was late 2005,
maybe 2006. That would stall NASA's first post-Columbia flight and completion
of International Space Station construction.
The estimated cost was
significant: More than $100 million to design and manufacture a full set for
the wing. There were operational challenge, too. Forty-four wraps -- one for
each unique wing panel -- would have to be built and hauled to the station to
be stowed for emergencies.
The killer was they might
not even work.
The U-shaped wraps would
fit over damaged panels like one taco shell over another. But they would jut up
ever so slightly from the wing. Even a minuscule rise, what engineers call a
"step" from the outer mold line, would generate excessive heat during
re-entry.
The bolts holding a wrap in
place would melt. And the wrap itself would melt or fall off, exposing the
damaged panel beneath to temperatures up to 3,000 degrees. Hot gas would
blowtorch through the wing. The shuttle would be ripped apart. Columbia all
over again.
That day, June 9, 2004,
Brieden recommended NASA put the concept on the back-burner and focus on
techniques for repairing small holes or cracks.
Columbia had been downed by
a 1.7-pound chunk of foam insulation that broke free from the shuttle's
external tank, blasting a 6- to 10-inch hole in a wing panel. But an extensive
effort to redesign the tank would preclude foam that big from shedding in the
future. Even in a worst case, only small wing panel cracks -- or holes less
than 4 inches in diameter -- might have to be fixed.
And other techniques would
be used to handle lesser damage.
Reaction varied.
At the end of the day, NASA
leaders decided to make over-wraps a long-term research project. At least for
now, the agency acknowledged defeat: NASA could not fix Columbia-like damage
any time soon.
"Nobody threw their
badge down, and I don't think there was even a dissenting position,"
Brieden said.
"I think there was a
realization that we had worked extremely, extremely hard on trying to give the
best answer to the program that we could. And there was no doubt that we had
tapped every talent we could.
"We didn't give it up
without a little sorrow ourselves."
HOUSTON: Management
pushes to find repair method
Shuttle Program Deputy
Manager Wayne Hale tried not to worry about the roller coaster of breakthroughs
and setbacks.
At the start of the shuttle
program, the best engineers in the world failed to figure out a way to have
astronauts repair heat shields in orbit.
"They actually gave
up," Hale said. "They didn't think it could be solved. Now we think
we're very close."
Even after the Columbia
accident, some folks at NASA were skeptical it could be done in the short term.
Technology might be better, but the shuttle and spacesuits were basically the
same. All told, not much had changed.
Except one thing. Resolve.
"You have to have the
laboratories; you have to do the tests," Hale said. "All that stuff
costs money, and at some point people say: 'We've done enough. We're not going
to spend any more money. We're just not getting there.' "
The message from the
bosses: "Keep at it."
CAPE CANAVERAL:
Astronauts ready to test repair options in space
Discovery commander Eileen
Collins was getting anxious.
Three months before launch,
senior managers were still debating what repair techniques to test on the first
post-Columbia mission -- the kind of decision normally made a year or more
earlier.
NASA had abandoned a method
for patching wing-panel holes as large as the one that doomed Columbia because
ground tests showed it probably wouldn't work. A complex "goo gun"
for thermal tile repairs wasn't ready to try on the flight.
Time for crew training was
running out.
"It is late,"
Collins said on a February trip to Kennedy Space Center.
The crew opposed testing
the "goo gun," which was designed to fill dents or gouges in thermal
tiles with heat-resistant material that would harden in place.
Already clad in cumbersome
spacesuits, spacewalkers would have to strap on a bulky holding tank. A
heat-resistant red goo would mix inside the tank, then flow through a 5-foot
hose before it was squirted out of a rifle-like metal wand. Plus, the goo was
difficult to apply. It didn't stick well to tiles. And it bubbled when mixed,
creating voids that could weaken a repair patch.
"We are not going to
fly it if it's not ready," astronaut Steve Robinson said at the time.
Managers decided to keep
things simple.
Side-by-side with Robinson
in the shuttle's cargo bay, Soichi Noguchi will coat damaged tiles, mounted on
a sort of workbench, with a primer-like, heat-resistant material.
Dabbed on with a device
like a liquid shoe polish dispenser, the "emittance wash" will
increase the amount of heat that damaged tiles could reject. Robinson will be
working with a caulk-gun and putty knife similar to those that can be bought at
the corner hardware store. He'll fill small wing-panel cracks with repair
material, then smooth the damaged area.
Inside Discovery, the two
also will try a method for fixing wing holes up to 6 inches wide. They'll paint
a sealant around punctured panel samples and cover the holes with composite
carbon patches held in place by expanding bolts.
All of the samples will be
brought back to a Houston lab and run through a simulator to see if they can
withstand the intense heat of re-entry -- up to 3,000 degrees.
The goo guns won't be
tested in orbit. But two will be aboard Discovery just in case.
"It's like having an
ejection seat in a jet aircraft," Robinson said. "You don't plan to
use it, but it is there."
HOUSTON: Hardware store
provides simple tools for tile fix
James Reilly went to work
in a dome-shaped vacuum chamber at Johnson Space Center, testing a new wing
panel repair technique that one day might save a shuttle crew.
Wearing a full-pressure
spacesuit, the veteran astronaut squeezed a bead of heat-resistant adhesive out
of a 9-inch caulk gun onto a palette. Then he took a standard putty knife and
worked the substance into a small crack, making the surface as smooth as possible.
Sounds simple, like
repairing cracked fiberglass on a boat. And the tools are not sophisticated.
"It's pretty much the
same things you would go down to Home Depot and buy and use in the house to put
spackling up," Reilly said. "That's what we started with.
"We just went down to
the local hardware store and bought a bunch of tools. And then we started
working with them to see what we liked and what worked and what didn't
work."
Doing repairs in space
poses unique problems.
First, the adhesive bubbles
up in a vacuum, weakening the material and making it less likely to survive the
intense heat of re-entry. The repair has to fill the entire crack smoothly. The
substance hardens fast and turns into a ceramic. Within a few minutes, it's too
hard and stiff to work with. The repair "is a little bit of an art,"
he said. But it works.
Wing panel samples that
Reilly repaired survived tests in a NASA re-entry simulator. Astronauts one day
might actually have to use the technique. That's because tests since the accident
have shown that cracks as small as one-15,000th of an inch -- about the width
of four stacked pieces of paper -- could allow hot gas to tear into the orbiter
on the way to the landing strip.
"Hopefully, we never
have to use it," Reilly said. "But everything that we've done up to
this point indicates that we can do it.
"And if I had to ride
home on it, there's not much choice. Give me a ride home."
Published
under license from FLORIDA TODAY. Copyright © 2005 FLORIDA TODAY. No portion of
this material may be reproduced in any way without the written consent of FLORIDA TODAY.
Florida
Today Special Report: NASA's Return to Shuttle Flight
Fixing NASA: Complete Coverage of
Space Shuttle Return to Flight