The Orlando Sentinel from Orlando, Florida • A18

Orlando Sentinel: PRODUCT: OS DESK: ASEC DATE: 02-23-2003 EDITION: FLA ZONE: FLA PAGE: A18.0 DEADLINE: 17.36 OP: eedwards COMPOSETIME: 22.23 CMYK SUNDAY, FEBRUARY 23, 2003 A18 Orlando Sentinel COLUMBIA DISASTER 100 tiles a flight damaged on average FOAM FROM Al fflf 1 belly during its Jan. 16 liftoff and may have cracked tiles or damaged the leading edge of the orbiter's left wing. That damage could have allowed su-perhot gases to get into Columbia's airframe during the fiery heat of re-entry, causing it to break up 207,000 feet over Texas on Feb. 1, killing its crew of seven. The focus on the foam is also prompting a tough look at NASA's decision-making, considering that the space agency has known for more than two decades that the debris posed at least some degree of hazard to its orbi-ters.

Critics say the acceptance of debris damage reflects a mind-set in NASA that, in order to keep flying what amounts to one of the world's most complex, dangerous machines, some risks just have to be tolerated. That argument was summarized last week by Neil Otte, deputy director of the tank project at NASA's Marshall Space Flight Center: "I think the bottom line was as it was from the very start of the program that in the shuttle program, we do have risks," Otte said in an interview. "We look at the propensity for something to happen. We look at the state of the art of it. We look at the consequences of the event.

We do a lot of testing to try and quantify that risk. We do a lot of bounding analyses to look at worst cases on a lot of these risks. "Through that, the foam was carried as a risk item. It was deemed as being a controlled risk and an acceptable risk." Michael Sutton, a professor at the University of South Carolina who analyzes the shuttle and other machines for their ability to withstand wear and tear, said that NASA does indeed carefully scrutinize the risks posed by the shuttle's most critical parts, such as its engines and internal-power units. But less-suspect parts such as foam insulation are evaluated primarily by their performance history, said Sutton, who thinks that the practice sets NASA up for catastrophe.

"You're fooling yourself thinking that because something didn't happen before, it never will happen," Sutton said. That tendency has become part of the agency's mind-set, said Diane Vaughan, a sociology professor at Boston College and author of the 1996 book The Challenger Launch Decision: Risky Technology, Culture, and Deviance at NASA "For making predictions about safety, the most important information they get is after a flight," she said. "When they continue to have damage within their experience base, it becomes OK." It's a point that was memorably made after the Challenger exploded in 1986, the victim of a poorly designed booster-rocket O-ring whose problems NASA had known about but tolerated. Wrote Richard P. Feynman, the Nobel Prize-winning physicist who sat on the presidential commission investigating the disaster: 'When playing Russian roulette, the fact that the first shot got off safely is little comfort for the next." We knew what to expecf From the earliest days of shuttle prototypes, foam was considered a nuisance but never a danger.

For example, after Sieck's first head-on foam-tile collision broke both, he and his engineers did more tests using his Formula Ford. They used varying weights of foam. And they set up the frames so the tile would strike the foam with only a glancing blow as most likely would happen during flight. They discovered that the foam NASA In 1979. Bob Sieck, then the shuttle's chief project engineer, sits in his Formula Ford race car, which was used to slam shuttle tiles the black panels above the roll bar -into a desktop-sized slab of foam insulation at 130 mph.

Tiles were shattered during a number of such tests on a 3-mile runway at Kennedy Space Center. siana until he retired last year. "It was never considered a flight-risk issue, just a cost issue," he said. Supersonic winds tear foam The tank, 154 feet tall and fabricated with 36,000 inches of welding, was thought of as tremendous engineering success. It was designed to hold on to the twin booster rockets when they snap to life with more than 6 million pounds of thrust.

The shuttle, with three engines producing more than a million pounds of thrust, piggybacks the tank. Built with an aluminum-alloy skin no thicker in some places than about a dozen pages of notebook paper, the tank carries 26 times its own weight in PLEASE SEE FOAM, A19 and in wind tunnels; they hired consultants to shoot pieces of it at tiles. They tinkered with the formula, punched thousands of holes in it, did risk-assessment analyses even as shuttle after shuttle returned to Earth with divots in heat tiles caused by chunks of foam. In fact, such debris primarily foam has hit and left "dings" on the shuttles no less than 15,000 times since 198 1 But knowing that the vast majority of those hits caused only superficial damage to the fragile tiles supported NASA's thinking that there was no risk to flight. "I considered the tank to be a fairly benign piece of the puzzle," said Tom Utsman, a former director of launch operations at Kennedy Space Center.

"Engines used to worry me to death. The tank was not high on our list of worries. We used to call it the big dumb tank. That's what it was." In fact, the greater concern was the cost of fixing foam-caused damage to the ceramic tiles that cover the underside of the shuttle and portions of its fuselage. On average, 100 "dings" had to be hand-filled with a special putty after every flight, or the tiles were replaced at a cost of up to $2,000 each.

Sometimes those "dings," gashes and gouges numbered 300 or more. "NASA's response was that they were not thrilled at the cost of repairing so many tiles," said Pete Hinkeldey, Lockheed Martin's former manager of material services, who oversaw external-tank metal work and insulation at its Michoud Assembly Facility in Loui would gouge the tiles but not break them. Their conclusion, one that NASA would reach many times, was that the tiles could be damaged extensively by foam but not to a degree that endangered the shuttle. "We knew what to expect," said Cocoa Beach retiree Billy "B.K." Davis, who at that time was the chief engineer for application and manufacturing of foam insulation. 'We had enough results that we said, 'OK, we should try to make sure this stuff won't come For the next 22 years, NASA would make intermittent efforts to try to ensure that the inch-thick polyurethane foam as light as the foam in an inexpensive beer cooler adhered to the shuttle's 15-story fuel tank.

Engineers tested it on jet fighters Shuttle developments FEB. 16 Engineers trying to determine how superhot gases could have entered Columbia and doomed the shuttle focus on a seal on the left landing-gear door and a possible hole in the left wing's leading edge. Volunteers abandon a search for debris in a canyon in New Mexico. FEB. 17 Some city officials and former workers at the plant in Palmdale, where shuttles underwent major re-furbishments, say politics and cost-cutting were behind the decision to shift the work to Kennedy Space Center.

FEB. 18 Investigators say they're becoming increasingly convinced that Columbia began shedding pieces somewhere over California on Feb. 1 but are pessimistic about finding debris in such a vast area. NASA announces that the panel investigating the accident will have additional freedom to recruit staff members and will release its report directly to the public. The announcements are meant to address criticisms that the board lacks independence from the space agency.

During the weekend, the board adds two new members from the private sector. FEB. 19 A NASA official tells the Orlando Sen been the focus of the public inquiry. The westernmost piece of debris so far is found a section of thermal tile near Littlefield, Texas. Engineers trying to extract information from 32 seconds of data sent by Columbia after contact was lost with the crew say the shuttle's major systems were functioning during the last two seconds of that timeframe.

FEB. 22 NASA has known for more than two decades that foam falling off the external fuel tank would pose at least some risk to shuttles. Critics say the acceptance of debris damage reflects a mind-set in NASA that, to keep flying one of the world's most complex, dangerous machines, some problems must be tolerated. tinel that before Columbia's accident, the space agency was redesigning part of its external tankand changing the way it applies insulating foam to the tank. Debris falling from the tank shortly after liftoff Jan.

1 6 is suspected of damaging the tiles that protect space shuttles from the heat of re-entry. The changes were to have been implemented later this year. In east Texas, searchers locate the landing gear from Columbia's nose. FEB. 20 NASA and private shuttle contractors acknowledge inviting retirees to return to work to help analyze information related to the investigation.

Critics say the recall underscores the impact of aging and downsizing on the NASA work force, what they maintain is a debilitating "brain drain" a loss of key managers, scientists and engineers. Searchers try to locate what is thought to be a large piece of shuttle debris in southeast Nevada that air-traffic controllers tracked by radar. FEB. 21 Documents show that three days before the accident, a NASA engineer complained to a colleague in an e-mail that the agency was not paying more attention to problems that might occur during re-entry if the ship had suffered a breach near its left landing-gear compartment. NASA says Columbia may have been hit by three pieces of debris, rather than the one large chunk that had 1 COLORSTRIP: I.