Space Shuttle Soon To Be Obsolete?

[Dreamer128]

Skeptics Say Shuttle Worn Out, Obsolete

By Eric Pianin and Kathy Sawyer
Washington Post Staff Writers
Monday, May 12, 2003; Page A01


As NASA picks up the pieces from the Columbia disaster and works on returning the three remaining space shuttles to flight, a growing chorus of skeptics is saying the 20-year-old space plane may have become unacceptably worn out and obsolete.

From the Columbia investigation board to Congress to academic specialists, the future of the shuttle program has come under intensive new scrutiny, with some saying that at the very least, NASA will find it far more difficult and costly than it anticipated to keep the complex vehicles flying safely.

NASA planners had once assumed the shuttle would be replaced sometime shortly after the turn of the century, but all efforts to come up with a replacement foundered over technical or budget hurdles. Now, with no other way to build and service the $100 billion international space station, the agency says it has no choice but to try to extend the life of the shuttle program to 2012 or beyond.

Key Republicans on Capitol Hill are furious that NASA has yet to develop a safer and more cost-efficient replacement for the shuttle. "I think we ought to scrap the program" or limit it to transporting only cargo, not humans, Rep. Joe Barton (Tex.), a member of the House Science Committee and longtime supporter of the space program, declared at a hearing last week.

Members of the Columbia Accident Investigation Board, meanwhile, have focused heavily on the possibility that the effects of aging caused crucial shuttle components to weaken, contributing to the disastrous chain of events that led to the loss of the orbiter and seven astronauts.

Beyond the immediate cause of the accident, "the whole question" of extending the life of the shuttles is "on the table," said retired Adm. Harold W. Gehman Jr., chairman of the investigating board. Gehman said the board's final report will address these concerns and present remedies that could add considerably to the cost and complexity of flying the reusable space planes.

That could have potentially profound implications for the future of human space flight over the next two decades.

NASA officials are hard at work planning to return the shuttles to flight, possibly next year, after implementing the board's recommendations. But it is far from certain that NASA will be able to rejuvenate the aging fleet, and continue operating it, in a way that satisfies the space agency's critics -- and is affordable.

"We are cautioning [NASA] to use the analogy" of commercial airliners, Gehman said, "in which you have to undergo a rigorous, expensive requalification or recertification program, and to be thinking along those lines. Even though each orbiter gets essentially hand tooled between every flight, it is not the same thing in our mind."

For skeptics concerned that the shuttle program is beyond saving, NASA officials have noted that the Air Force's current version of the B-52 bomber, which first rolled off the assembly lines in the 1960s, is still going strong. By comparison, the average age of the three remaining shuttles is just 16 years. Discovery was launched in 1984, Atlantis in 1985 and Endeavour in 1992.

But the shuttle program is so exotic and unique that it cannot fully mimic practices of military and civil aviation to assure that its aging vehicles are safe to fly, experts say.

Some aerospace engineers and scholars, including Alex Roland, a history professor at Duke University, warn that the space agency and Congress could be "courting disaster" by trying to extend the life of the complex, fragile and aging shuttle. "The wear and tear of going in and out of space is greater than we anticipated, and that wear and tear simply grows with time," said Roland, a former NASA historian.

Paul A. Czysz, professor emeritus of aerospace and mechanical engineering at St. Louis University, added: "The shuttle really has a problem in that it's fragile, like an eggshell. Once you crack the leading edge, it breaks open."

Even with less exotic vehicles, "we are in unprecedented areas in dealing with aging aircraft," Robert Ernst, head of the Navy's Aging Aircraft program at the Patuxent River Naval Air Systems Command in Maryland, told shuttle investigators at a recent hearing.

Columbia -- the oldest of the five original space planes -- was first launched in 1981 and had flown 27 missions before the accident. Challenger, first launched two years after Columbia, blew up during a 1986 launch. Each shuttle was designed for 100 flights, but because they have flown much less frequently than originally planned, their "design life" has been extended across more years. This piles the effect of passing time on top of the stresses and fatigue of space flight.

At NASA, however, the official line is more positive. Michael Greenfield, NASA's chief of technical activities, said during a recent interview that "there is no inherent barrier for us to continue to fly the shuttle" well into the next decade or beyond.

"The vehicle is well-behaved, incredibly well-behaved, and I believe our safety processes work," Greenfield said. "We're going to find this problem and fix it."

The shuttles -- the only reusable manned spacecraft operating in the world -- were difficult enough to maintain when their millions of parts were new. The effects of aging have added to the challenge, as well as adding an immeasurable degree of uncertainty.

The Columbia investigators have concluded that damage to the tough carbon composite material that shields the wings against the heat of reentry precipitated that disaster, and tests have also shown that a hidden effect of aging -- oxidation that eats into surfaces -- might have degraded the heat shielding and contributed to the deadly chain of events. But no one knows for sure.

"Our finding was that NASA doesn't know" how aging affected the crucial hardware, Gehman said last week.

Michael C. Kostelnik, director of NASA's shuttle and space station programs, has acknowledged that in general, "there is a lack of certainty about the impact of age on aerospace structures."

Even before the latest accident, the shuttles regularly underwent intensive maintenance and updating. NASA technicians routinely fixed dings and other detectable damage to the orbiter that occur during the tumult of ascent and descent through the Earth's atmosphere.

And NASA has paid considerable attention to what agency Administrator Sean O'Keefe calls "modifications, upgrades and technology insertions." After every eight to 10 flights, technicians tear each shuttle down and rebuild it into what officials describe as essentially a "spanking new" vehicle. Columbia had undergone two such overhauls, the latest performed in late 1994 and early 1995 in Palmdale, Calif.

But much of the space plane is not replaced. In fact, accident investigators found that most of the crucial heat-shield panels on Columbia's wing leading edges, site of the fatal breach, were original hardware.

Outside experts suggest that safely maintaining the shuttles for many more years may be a tougher challenge than NASA envisions, in part because of new requirements the board may place on the program, and in part because of disadvantages specific to human spaceflight, such as reliance on a small number of expensive vehicles.

But there is another big factor, experts say. The entire aerospace enterprise is going through the aging process for the first time in history, which means a number of aspects of the problem are poorly understood and engineers are still being surprised by unexpected effects from long-term stress on flying machines.

"It's not like we can go back and find the predecessor of the B-52 and see how it did in its 45th year. There isn't that data," Ernst said. "There's no idiot light that just sits there and goes, 'Ding. Replace this aircraft and buy new aircraft.' "

Too little is known about how aging affects wiring, composite materials, pumps, motors and other components, Ernst and others say. Stresses and strains may produce unexpected wear and tear, even more for spacecraft than for aircraft. What seems certain is that the labor demands and other problems soar with age.

Even the venerable B-52s so often cited by NASA were plagued by corrosion when based in Guam and other areas of Southeast Asia. They were shifted to more benign environments and a policy of "zero tolerance for corrosion" was instituted, said Jean Gebman, a senior engineer at the Rand Corp. who has studied aging aircraft issues. But the shuttle base is still perched at Cape Canaveral on the highly-corrosive, humid, salty Atlantic shore.

When older aircraft are sacrificed in what is called a tear-down inspection, technicians inevitably find previously hidden signs of corrosion, he said -- as accident investigators have found in inspections of shuttle parts.

One of the clear advantages the aviation industry has over the shuttle program is that it has flown huge numbers of vehicles a lot of times -- enough to have built up a viable statistical database in at least some areas, and enough to sacrifice some craft to the inspections.

The fact that the entire shuttle "fleet" is now down to three vehicles severely limits the amount of poking and shaking that engineers can do on actual flight hardware. "If we had hundreds or even tens, we'd consider tearing down the older ones. But when you're down to three, that's not an option," Gebman said.

The low vehicle count also limits the supply of spare parts, he said. If one of the three shuttles is needed to support the operations of the other two with cannibalized parts, "it means you only have one backup. That makes it very thin."

For now, NASA has little choice but to try to keep the shuttles flying. The agency is developing a smaller orbital space plane to ferry astronauts to the space station. But it will not be able to carry heavy cargo and is not expected to be operational for at least six to eight years. Last week, the plan came under heavy criticism at a congressional hearing.

Last November, after months of debate, the Bush administration and lawmakers agreed to fiscal 2003 budget amendment language declaring that the space shuttle "will continue to be the workhorse of the civil space program, and will be flown through at least the middle of the next decade." A planning document, NASA's "new integrated space transportation plan," contains scenarios for possibly extending the shuttles' life "until 2020 or beyond."

House Science Committee Chairman Sherwood L. Boehlert (R-N.Y.), a leading proponent of the space program, agrees that Congress and NASA have no alternative. "To think we could phase out the shuttle by the end of this decade is just unrealistic," he said last week. "It's at odds with the facts."

O'Keefe insists that there is no target date for retiring the shuttles. Much will depend on the findings of the Gehman board, he said, as well as on the results of NASA's own preparations to return the shuttles to flight and its longer-term shuttle Service Life Extension Program.

"I have never been particularly fond of a date or wed to any date," O'Keefe has said. The important question is, "How long can we maintain this in its optimum operational configuration that maintains or at least preserves safety of flight considerations?"

The problem for NASA, several experts cautioned, will be knowing when the shuttles are about to cross that line.


© 2003 The Washington Post Company


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[/)eathKiller]

why I do belive the replacement will be this: