Джеймс Глик - Genius - The Life and Science of Richard Feynman

Through Graham he arranged a series of private briefings on Saturday at NASA’s Washington headquarters. He learned more about the engines, the orbiter, and the seals.

He found again that the agency’s engineers understood a long history of difficulties with the O-rings; that two- or three-inch segments of the thirty-seven-foot links had repeatedly been burned and eroded; that a critical issue was the speed with which the rubber had to press into the metal gap—in mil iseconds; and that the space agency had found a bureaucratic means of simultaneously understanding and ignoring the problem. He was particularly struck by a

summary of a meeting between Thiokol and NASA managers the previous August. Its recommendations seemed incompatible:

• The lack of a good secondary seal in the field joint is most critical and ways to reduce joint rotation should be incorporated as soon as possible to reduce criticality… .

• Analysis of existing data indicates that it is safe to continue flying… .

Elsewhere at NASA headquarters that day, Graham learned that a storm was about to break: the New York Times had obtained documents showing urgent warnings within NASA about O-ring problems over a period of at least four years. Graham had taken control of the agency only recently, when the administrator, James Beggs, was indicted on fraud charges unrelated to NASA. He immediately telephoned Rogers.

The article appeared Sunday, quoting warnings even more dire than those the engineers had shown Feynman: that a failure of the seals could cause “loss of vehicle, mission, and crew due to metal erosion, burn-through, and probable case bursting resulting in fire and deflagration,”

and that

There is little question … that flight safety has been and is being compromised by potential failure of the seals, and it is acknowledged that failure during launch would certainly be catastrophic.

That morning Graham himself took Feynman to the Smithsonian Institution’s National Air and Space Museum, where he sat in a cavernous theater and watched an inspirational giant-screen film about the space shuttle. He was surprised at how emotional he felt.

In the afternoon Kutyna cal ed Feynman at his hotel. As shuttle program manager for the military, Kutyna knew the shuttle more intimately than any other commissioner. He also knew how to run a technical commission, because he had headed the air force’s own investigation into the explosion of a Titan rocket the year before. And he had his own information sources among the engineers and astronauts—one of whom told him over the weekend that Thiokol had known of a potential loss of resiliency when the rubber O-rings were cold. Kutyna wanted to bring this information into the open without jeopardizing his source.

He invited Feynman to his house for Sunday dinner.

Afterward they went out to his garage—he col ected junk cars as a hobby, and at the moment he was working on an old Opel GT. Its carburetor happened to be sitting on his workbench. He told Feynman, you know, those things leak when it’s cold, so do you think cold might have a similar effect on the shuttle O-rings?

Rogers cal ed a closed meeting Monday in reaction to the New York Times revelations. He made clear that he considered them a disruption of his proceedings: “I think it goes without saying that the article in the New York Times and other articles have created an unpleasant, unfortunate

situation. There is no point in dwel ing on the past.” NASA representatives were asked to respond: “I think that his statement in here where he says that it might be catastrophic I think is overstated,” said one, and Rogers remarked, “Wel , that may be.” Lawrence Mul oy, project manager for the solid rockets testified that the rubber in the O-rings was required to operate across an enormous temperature range, from minus 30 to 500 degrees Fahrenheit. He did not know of any test results, however, on the actual resiliency of the O-rings at low temperatures.

Mul oy returned the next morning to give the commissioners a briefing—another in the genre that Kutyna thought of as “tel ing which was the pointy end of the shuttle because they don’t know that much about it.” He brought more than a dozen charts and diagrams and gave a vivid flavor of the engineering jargon—the tang end up and the clevis end down, the grit blast, the splashdown loads and cavity col apse loads, the Randolph type two zinc chromate asbestos-fil ed putty laid up in strips—al forbidding to the listening reporters if not to the commissioners themselves.

“How are these materials, this putty and the rubber, affected

by

extremes

of

temperature?

…”

one

commissioner asked.

Yes, sir, there is a change in the characteristic. As elastomers get colder, the resiliency decreases, and the ability to respond——

Now, the elastomers are what?

That is the Viton O-ring.

The rubber?

Feynman pressed Mul oy on why resiliency was crucial: a soft metal like lead, squeezed into the gap, would not be able to hold a seal amid the vibration and changing pressure. “If this material weren’t resilient for say a second or two,” Feynman said, “that would be enough to be a very dangerous situation?”

He was setting Mul oy up. He had been frustrated by the inconclusive and possibly evasive testimony. He had made an official request for test data, through Graham, and had received documents that were irrelevant, showing how the rubber responded over a period of hours instead of mil iseconds. Why couldn’t the agency answer such a simple question? At dinner Monday night his eyes fel on a glass of ice water, and he had an idea that he first thought might be too easy and gauche. Ice water was a stable 32

degrees, almost exactly the temperature on the pad at the time of the launch. Tuesday morning he rose early and hailed a taxicab. He circled official Washington in search of a hardware store and final y managed to buy a smal C-clamp and pliers. As the hearing began, he cal ed for ice water, and an aide returned with cups and a pitcher for the entire commission. As a life-size cross section of the joint was passed along for the commissioners to examine, Kutyna saw Feynman take the clamp and pliers from his pocket and pul a piece of the O-ring rubber from the model. He knew what Feynman meant to do. When Feynman reached for the red button on his microphone,

Kutyna held him back—the television cameras were focused elsewhere. Rogers cal ed a short break and, in the men’s room, standing next to Neil Armstrong, he was overheard saying, “Feynman is becoming a real pain in the ass.” When the hearing resumed, the moment final y arrived.

CHAIRMAN ROGERS: Dr. Feynman has one or two comments he would like to make. Dr. Feynman.

DR. FEYNMAN: This is a comment for Mr. Mul oy. I took this stuff that I got out of your seal and I put it in ice water, and I discovered that when you put some pressure on it for a while and then undo it it doesn’t stretch back. It stays the same dimension. In other words, for a few seconds at least and more seconds than that, there is no resilience in this particular material when it is at a temperature of 32 degrees.

I believe that has some significance for our problem.

Before Mul oy could speak, Rogers cal ed the next witness, a budget analyst who had written a memorandum that formed the basis of the Times article. The analyst, Richard Cook, had noticed the O-ring problem on a list of

“budget threats” month after month, had highlighted it to his superiors, and, when the disaster took place, felt certain that it had been the cause. The chairman, for the first and last time during the shuttle hearings, cross-examined a witness, through the rest of the morning and on into the afternoon, with the cold savagery of a prosecutor: