Orlando Sentinel August 22, 2003
Shuttles Risk May Remain
By Kevin Spear and Jim Leusner
At the instant of a fiery liftoff, an array of finger-size explosives is supposed to shatter the steel nuts that anchor a space shuttle to its launch pad.
But for shuttle Atlantis, something went very wrong last year. Detonation charges planted in the eight hold-down nuts - each as big as a saucepan and weighing nearly 10 pounds - failed.
Separate firing signals did trigger backup explosives, and Atlantis thundered into orbit. But ground personnel - who never could find the cause of the failure - were left chilled by the specter of anchors not letting go of a shuttle that has unleashed 7.8 million pounds of launch thrust.
"Some people still involved in the program confided to me that they have been awakened in the night with nightmarish pictures of the vehicle cartwheeling off the pad," said Bill Heink, who retired in 2000 as site director of The Boeing Co. shuttle operations at Kennedy Space Center. "The potential is there."
Hold-down anchors are only one example of persistent defects and breakdowns that have plagued the shuttle since the first launch in 1981.
An Orlando Sentinel review of NASA's hazard-evaluation studies and nearly 2,000 malfunction reports from the 113 shuttle flights found a half-dozen hardware systems - all critical to successful launch, orbit and landing - that have persistently faltered or failed during flight. In many instances, they have been treated and accepted in much the same fashion that NASA reacted to ongoing flaws that doomed Challenger and Columbia.
The systems aren't thought to be as inherently dangerous as, for example, the shuttle's main engines, which are considered most likely to trigger catastrophe.
But the foam that insulates the shuttle's external fuel tank - and which regularly ripped loose from the tank and pelted the orbiters - wasn't considered inherently dangerous either.
Even after engineers determined Columbia had been struck by a chunk of foam shortly after liftoff, NASA did not believe it could do enough damage to lead to the destruction of the shuttle.
The agency was wrong.
Now, as NASA prepares to return the three remaining shuttles to flight, the Columbia Accident Investigation Board - which expects to release its final report Tuesday - is asking, in effect: What could be the next foam disaster? Board chairman Harold Gehman Jr. said he's told his investigators: "If these flaws are out there . . . tell me what the next one is."
Among the possibilities, according to Sentinel research:
Entire banks of the orbiter's 44 jet thrusters, needed for precise maneuvers in space, fail in varying degrees during most flights. In 1995, damaged thrusters aboard Discovery spewed hazardous fuel as it approached the MIR space station, much to the alarm of the Russians inside.
Electric arcing from damaged wire caused a shutdown of computers that controlled two of three main engines aboard Columbia in 1999. A backup system took over. But despite subsequent studies suggesting damage and deterioration of aging wiring, not all of it has been replaced.
NASA relies on exploding nuts and bolts to trigger the separation of the solid rocket boosters and external fuel tank from the shuttle. But devices designed to capture this pyrotechnic debris have repeatedly failed - most recently during Columbia's last flight - raising the potential of chunks of metal ripping into the body of the shuttle.
At least one of the three auxiliary-power units, which provide hydraulic pressure needed to steer the orbiter, has failed in some fashion in most flights, usually because of overheating. Some have even caught fire during landing. NASA engineers were so worried that they commissioned in the late 1990s a major redesign of the power units - but pulled the plug because of soaring costs.
NASA has been unable to prevent episodes of highly explosive hydrogen gas - which leaks from the external fuel tank - accumulating beneath the shuttle as it sits on the launch pad. High concentrations of the gas have prompted several aborted launches.
NASA engineers and the flight hazard reviews acknowledge that each has the potential to fail in ways that lead to a major accident. The investigation board has asked the agency for details on several of those issues.
And like the foam that led to Columbia's breakup over Texas on Feb. 1, and the booster joint O-rings that doomed Challenger in 1986, all six have defied NASA's various efforts to fix them.
When a malfunction occurs, NASA often replaces parts and may even do extensive troubleshooting. But given limited budgets and the aging technology of the shuttles, the agency often has been unable or unwilling to come up with permanent solutions.
Instead, NASA documents show, the space agency has accepted the risks.
"It's fair to say they got comfortable with these," said Duke University professor Alex Roland, a former NASA historian who follows the space agency. "They were rather just crossing their fingers and hoping. And if it didn't do what they once feared it would do, they accepted that and just moved on."
The Sentinel asked NASA for more than a week to provide engineers, executives or documents to explain how the agency has handled the problems. NASA responded by passing the requests to the United Space Alliance, the private company that runs day-to-day shuttle operations. A NASA spokesman also said the company had indicated that "it will take a great deal of time" to respond.
To critics of NASA, the agency's willingness to continue flying without fixing these problems is part of a failed organizational culture that must be fixed if the shuttle is to return safely to flight. NASA engineers, they say, are too willing to assume the best, in order to keep the shuttle flying and control costs.
"The answer to this is to go back and try to understand what you don't understand," said John Pike, director of GlobalSecurity.org, a space policy think tank. "You have to go back and look at what parts of your understanding on the shuttle are based on assumptions, and which ones are based on conclusions."
Sentinel Space Editor Michael Cabbage contributed to this report.
© Copyright 2003
