NASA Propelled by Schedule Pressure, Report Says

External Tank-119 (ET-119) arrived by barge at NASA's Kennedy Space Center in Cape Canaveral, Florida in early March 2006. CREDIT: NASA/KSC.

CAPE CANAVERAL - Three months before the planned launch of shuttle Discovery and seven astronauts, NASA again is under dangerous pressure to fly so it can finish the International Space Station by 2010.

Once again, NASA has delivered a revamped external fuel tank to Kennedy Space Center before finishing tests to prove whether it is safe to fly.

This time, decisions will be colored by that mortifying moment last July when Discovery's right wing was almost struck by another chunk of orange foam insulation from the tank, a piece similar to the debris that doomed Columbia three years ago.

Managers insist they will delay the launch if tests show conditions could lead to another disaster, which would prompt an early shutdown of the shuttle program and the loss of thousands of jobs in Brevard County.

"Is there a potential that you would fly something that you have less than full confidence in just because you're already going down the path toward flight?" said John Chapman, manager of the external tank project at Marshall Space Flight Center in Alabama. "The answer to that is absolutely not.

"There is absolutely zero intent to fly that tank before that work is complete. . . . It's as simple as that."

However, a FLORIDA TODAY review of NASA documents shows that agency managers bowed to schedule pressure during NASA's attempt to return the shuttle fleet to service after the Columbia accident. The records show that some engineers argued for changes to the part of the tank that shed foam on Discovery's flight, but were overruled by managers.

The review also showed:

• Discovery was cleared for flight last year even though a redesigned external tank failed to meet stricter safety standards set after the 2003 Columbia catastrophe.
  
• NASA managers changed ground rules of crucial engineering analyses, avoiding further modifications to a tank already at KSC.
  
  
• Discovery's fragile heat shield suffered more debris hits than orbiters on prior flights, but the damage was less severe.

In February 2003, Columbia's seven astronauts died when their shuttle disintegrated over Texas during atmospheric re-entry. Investigators blamed a hole in the heat shield, caused when a piece of tank insulation broke free during launch and struck the left wing at high speed.

Today, this much is clear: NASA never will be able to completely stop the foam insulation from breaking free from external tanks in flight. But the agency has made significant progress in preventing debris large enough to cause catastrophic damage to an orbiter.

"You guys ought to be aware, and we have got to make it clear to everybody we talk to, when we launch the next flight, there is still going to be foam come off the tank," shuttle program manager Wayne Hale told KSC workers in a meeting last month.

"We have not got a plan in place that is going to eliminate all foam loss off the tank," he said. "That is a big goal, and we don't think we are going to get there in the life of the program."

Near-hit

NASA concedes the near-hit on Discovery averted the kind of damage that could have triggered a risky rescue mission. Astronauts would have docked at the space station and waited while NASA scrambled to launch a second shuttle.

With Discovery, a 3-foot (almost one-meter) slab of foam broke away from a long wedge of insulation -- dubbed a Protuberance Air Load ramp, or PAL ramp -- designed to provide a wind shield for critical fuel pressurization lines and electrical cables that run along the outside of the tank.

Two independent review teams said schedule pressure played a role in decisions about the extent of safety modifications the agency would attempt before Discovery's flight last summer.

Lower-level engineers flagged the 38-foot (11-meter) PAL ramp for removal, modification or extra inspections. They knew the handcrafted wedge was susceptible to shedding large chunks of debris.

It now appears their suggested changes could have made a difference.

NASA removed and replaced 10 feet (three meters) of the ramp to make other changes in the area. On that section, workers used a new and improved process to reapply the foam. The debris later shed during Discovery's launch came from the 28-foot part (8.5-meter) of the ramp that had not been replaced.

At the time, managers planned to fly two more missions while engineers completed the analyses.

Changing rules

Discovery was on the launch pad at KSC last spring before NASA finished analyses aimed at showing whether the redesigned tank met stricter new requirements for reducing launch debris. The reviews ultimately showed the tank did not meet standards.

But rather than change the tank itself, managers changed the ground rules for the debris analyses. Several members of an independent oversight group took exception with that approach.

"The middle of a design review does not seem an appropriate time to be changing the rules," they said in comments added to the Return To Flight Task Group's final report. A NASA manager told them, "That's why we're changing the models, so we don't have to change the tank."

Ultimately, NASA conceded foam or ice debris large enough to cause catastrophic damage still could come off parts of the modified tank.

A post-flight inspection report shows that Discovery was battered by debris during last July's flight.

A total of 176 dings and gouges were counted on fragile heat-shielding materials designed to protect the orbiter and its crews from the intense heat of re-entry. The average on previous flights: 144.

Armando Oliu, the head of NASA's ice and debris inspection team at KSC, said the majority of the damage was minor. That's a sign that the agency is making progress toward eliminating the worst debris.

"We know the external tank is producing the majority of those debris hits, but it's from small particles," he said. "What we've reduced is the potential for a major hit."

Modifications

NASA managers decided late last year to remove PAL ramp foam from the tank now being readied for the next shuttle flight. Engineers think it will be safe to fly the tank without the ramp, but conclusive tests and analyses are ongoing.

"Your gut says it's probably an OK thing to do, but you don't want to bet the safety of the vehicle on intuition," Hale said.

Wind tunnel tests are under way in California and Ohio. Additional tests are scheduled in Tennessee in June. Discovery is set to launch July 1.

Hale says he would postpone the launch if the tests prove fuel pressurization lines or electrical cables might be ripped off in flight without the PAL ramp to protect them.

"You don't want to fool around with that because you can't stand for those things to come loose when you go Mach 4. That would be a bad thing," Hale said. "If the answer comes back and says the cable tray will come off, then that's not something we're going to fly with."

Published under license from FLORIDA TODAY. Copyright ? 2006 FLORIDA TODAY. No portion of this material may be reproduced in any way without the written consent of FLORIDA TODAY.

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