[FPSPACE] Columbia Crew

[E.P. Grondine]

Matt - 
They don't talk frankly about this much either:
WASHINGTON  — Two years before the 
Columbia disaster, NASA safety experts fearing similar damage to delicate heat 
tiles on the space shuttle Atlantis decided it was "prudent" to adjust its 
return path to lessen danger during the fiery descent, according to internal 
documents.














NASA has maintained since last week's disaster that there was no recourse 
after liftoff for the seven astronauts aboard Columbia if there was serious 
damage to those tiles. But the Atlantis mission, in which the crew was 
instructed to make a protective re-entry, suggests there were at least options 
for an ailing shuttle to return safely. 
Experts during the Atlantis mission, 
in May 2000, feared damage to tiles on the wing, like Columbia, and over a 
slightly smaller area than the damage suspected to the shuttle that 
disintegrated over Texas last weekend, documents show.
In both cases, engineers believed the 
damage was not a threat to safety. But NASA took the extra precaution in the 
Atlantis case, the documents show.
NASA spokesman Michael Braukus said 
Friday the space agency did not consider ordering Columbia to make the same 
maneuver, and believes now that it would have interfered with efforts to warm 
Columbia's landing gear tires for a safe landing.
The tires were unusually cold because 
Columbia orbited the planet for days with its landing gear aimed toward deep 
space, he said.
The maneuver, called 
"thermal-conditioning," was described as far back as 1990 for NASA by 
researchers. It involves pivoting the shuttle slightly left or right before it 
speeds through earth's atmosphere so that damaged tiles on one side might be 
exposed to lower temperatures.
It's akin to a football player 
turning his body to favor an injury as he's tackled.
Since Columbia's fiery breakup 
Saturday, NASA officials have maintained there was no recourse for any shuttle 
that reaches orbit with damaged tiles.
"We couldn't do anything about it 
anyway," shuttle program manager Ron Dittemore said earlier this week. "Our only 
effective action is to prevent the loss of tiles through design and through 
test. And that has been perfectly adequate up to this point."
Atlantis adjusted its return flight 
because experts noticed a 6-inch ice chunk from its external fuel tank shattered 
about 8 feet from one of the hinged, flap-like devices, called "elevons," along 
the back of the wing that help the pilot steer.
"It was prudent to take some 
precautions," according to NASA documents. The maneuver to pivot Atlantis to 
protect its right wing "increased the temperature margin and therefore reduced 
the potential for structural damage."
Engineers similarly feared damage to 
tiles on Columbia's left wing, but they did not instruct Columbia to perform 
such a protective maneuver. NASA officials believe the shuttle disintegrated 
over Texas shortly after it performed a routine turn to slow down. The first 
sign of problems was the loss of temperature readings from systems controlling 
Columbia's left-wing elevons.
NASA confirmed Friday it received 
photos of Columbia from a powerful Air Force ground camera, but Dittemore -- who 
showed one of the images to reporters -- said it wasn't clear whether it showed 
structural damage to Columbia's left wing.
"All by itself, I don't think it's 
very revealing," he said.
The damage in May 2000 to Atlantis' 
right wing "was not considered a safety of flight issue," NASA's documents show. 
Inspectors later found a gouge in thermal tiles there, measuring about 5.25 
inches by 1.5 inches by one-half inch.
NASA officials have said they also 
concluded that possible damage to Columbia's insulating tiles didn't threaten 
the shuttle's safety. They based their conclusions on scientific models showing 
possible damage over an area about 7 inches by 32 inches -- larger than the 
damage to Atlantis years earlier.
Outside experts said it was 
impossible to know yet whether flight adjustments by Columbia could have 
prevented its destruction.
"You can yaw the vehicle to the side, 
you can roll the vehicle a little bit," said Steven P. Schneider, an associate 
professor at Purdue University's Aerospace Sciences Laboratory. He said some 
shuttle surfaces, such as near the fuselage or the back edges of the wings, 
could be better shielded during such maneuvers than others. "You can't change 
the trajectory too much."
A 1990 study for NASA by outside 
researchers said threats to the shuttle from damaged thermal tiles -- which 
protect against temperatures that can reach 3,000 degrees -- could be lessened 
by rerouting important internal systems or changing the shuttle's re-entry 
profile. Using that technique, researchers wrote, "it may be possible to reduce 
the temperature of some weak, vulnerable areas."
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