Losing Battle to Delay Shuttle Flight Detailed

In testimony charged with emotion, engineers for the firm that builds space shuttle rockets said Tuesday that they waged a desperate, losing struggle during the night before the ill-fated Challenger flight to persuade space agency officials and their own supervisors that launching in the bitter cold weather would risk catastrophe.

The engineers, testifying in arresting detail before a presidential commission investigating the Jan. 28 disaster, described how their arguments were stymied by National Aeronautics and Space Administration officials and by hasty reinterpretations of data by their own superiors at Morton Thiokol Inc.

And their accounts revealed that the tragic chain of events believed most likely to have destroyed the Challenger was foretold--in startlingly clear terms--by top rocket experts the night before launch.

“I made the direct statement that if anything happened to this launch . . . I sure wouldn’t want to be the person who had to stand in front of a board of inquiry to explain why I launched this . . .” recalled Allan J. McDonald, an engineer with Morton Thiokol for 26 years, who was the company’s top representative at Kennedy Space Center for the Challenger flight.

“When I made that statement, no one commented about it,” McDonald told the panel in the first of two days of public hearings. The second hearing is scheduled today.

The four Morton Thiokol engineers who testified Tuesday accused NASA of forcing Morton Thiokol into the unprecedented position of having to prove that the launch would be dangerous--a departure from the space agency’s historic stance that contractors demonstrate why a mission was safe.

Their testimony--along with that of three company executives--also yielded the startling vision of decisions that involved the safety of seven crew members being made in disregard or ignorance of NASA launch standards.

“I felt personally that management was under a lot of pressure to launch . . . “ said Roger Boisjoly, a Morton Thiokol engineer who is a rocket seal expert. “One of my colleagues who was in the meeting summed it up best: This was a meeting where the determination was to launch, and it was up to us to prove beyond a shadow of a doubt that it was not safe to do so.

“This was in total reverse to what the position usually is in a preflight conversation or a flight readiness review. It’s usually exactly the opposite.”

Boisjoly also testified that, contrary to previous NASA testimony before the commission, he had warned as early as last summer that unless problems of erosion in rocket booster seals were corrected, “we stand in jeopardy of losing a flight and all the launch-pad facilities.”

Leave Without Comment

More than a dozen ranking NASA officials were in the audience at the session, but left without commenting on the testimony. Space agency propulsion experts who took part in the prelaunch discussions with Morton Thiokol are expected to testify today.

In addition, the Associated Press reported that Rocco Petrone, president of the space division of Rockwell International, is expected to testify today that he also objected to the launch because of the cold weather. An unidentified source was quoted by the AP as saying: “We now have two contractors protesting the launch.”

Much of Tuesday’s testimony had been taken 10 days before in a private commission session, but the witnesses on Tuesday nonetheless evoked from commission members a previously unseen emotional edge, bordering at times on outright anger.

The commissioners pressed Morton Thiokol executives with increasingly tough questions, and made little attempt to hide their dismay with answers that danced around the central issue of why the executives did not stand behind their own engineers and oppose the launch.

Former Secretary of State William P. Rogers, chairman of the commission, at one point asked Morton Thiokol Executive Vice President Gerald Mason if he fully realized that the company’s recommendation in effect determined whether the Challenger was to be launched.

Mason swallowed and his voice caught in his throat as he answered: “Yes, sir.”

‘Not Convincing’

At another point, Rogers expressed skepticism with the managers’ explanations for overruling their engineers, telling one Thiokol manager: “We’ve heard the explanation you’ve given. The problem we’re having is: It’s not convincing.”

Alton G. Keel Jr., the commission’s executive director, pointedly asked Mason what he had meant when, before a final poll on whether to recommend launch, he told a vice president for engineering “to take off your engineering hat and put on your management hat.”

When asked whether that remark had placed pressure on Robert Lund, a subordinate to Mason, to go against the recommendation of his engineers, Mason responded: “Well, I hope not. But it could be interpreted that way.”

At first, the Morton Thiokol engineers said, they had convinced their superiors that cold weather might hamper the effectiveness of critical O-ring seals in the booster rockets. The seals, made of synthetic rubber, had been a source of mounting concern, having shown evidence of charring or erosion on 22 previous occasions.

‘Black as Coal’

The worst such incident had occurred a year before, on a flight launched in 53-degree weather--the previous record cold. In that flight, hot gases had passed the primary O-ring and charred a back-up seal to the point where, Boisjoly testified, “it was as black as coal.”

Weather forecasts for the Jan. 28 launch, which had been rescheduled three times largely because of weather-related delays, called for temperatures in the mid-20s at the time of liftoff. When engineers at Kennedy Space Center heard of these forecasts, they began contacting colleagues at Morton Thiokol’s Utah facility and the NASA propulsion center in Huntsville, Ala.--beginning a process of gathering data about what the weather might do to the rocket seals.

Crucial in the engineers’ calculations was evidence that O-rings--which act as washers in the rocket joints to contain hot propellant inside the casing--stiffen in colder temperatures. Thus they could be expected to move more slowly in the instant of rocket ignition, when they are supposed to move across a tiny gap in the joint and form a perfect seal where the metal tongue of the top section inserts into the metal lips of the lower section.

“It would be like trying to shove a brick into a crack rather than a sponge,” is how Boisjoly described the effect of harder O-rings.

Secondary Ring

The primary O-ring is expected to fill the gap between the joint sections in less than two-tenths of a second. During this time, it is believed to be backed up by the secondary O-ring.

But forces generated by the rocket that tend to want to pull the sections apart begin three-tenths of a second after ignition, placing a greater strain on the rocket joints. During that time, the tugging can prevent the secondary O-ring from forming a proper seal, stripping the system of the redundancy that is supposed to make it fail-safe.

Aware of this potential, NASA in 1982 had declared that the primary O-rings were a “critical item”--meaning that their failure would mean loss of spacecraft and crew.

The Morton Thiokol engineers testified Tuesday that after data was presented to their supervisors the night before Challenger’s launch, it was agreed to oppose launching in temperatures less than the previous record low that had produced extensive but survivable O-ring damage.

The 53-degree limitation surprised NASA officials.

“That temperature brought a lot of strong comments and reaction from several of the NASA officials,” testified McDonald, the Morton Thiokol representative at Cape Canaveral. “I believe it was Mr. (Lawrence B.) Mulloy, (manager of NASA’s solid rocket projects office in Huntsville) who made some comments about when will we ever fly if we have to live with that . . . and also the comment that we were trying to create new launch commit criteria.”

Another NASA official, George Hardy, deputy director of science and engineering at Huntsville, was said by witnesses to have responded that he was “appalled” by the Morton Thiokol recommendation, but nonetheless conceded that there would be no launch without a Morton Thiokol approval.

McDonald, Boisjoly and other witnesses testified that NASA originally asked for a more thorough presentation on the data. This was done in a teleconference linking Kennedy Space Center officials with officials elsewhere in the country.

Persuasive Argument

Witnesses said Mulloy gave a persuasive five-minute argument challenging Morton Thiokol’s interpretation of the data.

One of the key arguments against the recommendation, they said, was that a previous launch that caused O-ring erosion had come in warm weather, indicating that perhaps weather was not a factor in the erosion dynamics.

At this point, witnesses testified, Morton Thiokol asked for a five-minute caucus to re-evaluate its position and went off the telephone line for 30 minutes.

During this caucus, the Morton Thiokol engineers testified, support from their superiors seemed for the first time to ebb. Instead of supporting the engineers as they had earlier, the executives began looking for ways to reinterpret the data so as to justify launching despite the cold weather.

On Verge of Tears

In his testimony, Boisjoly’s voice broke and he appeared on the verge of tears as he described how during the 30-minute caucus he and co-witness Arnold Thompson, a veteran of 26 years with Morton Thiokol, used diagrams and photographs of seal damage on previous flights in a last-ditch effort to dissuade management officials from reversing an earlier prelaunch decision to postpone until the weather warmed.

“We couldn’t understand why it was going to be reversed,” he said. “Arnie, after he got up from his position, which was down the table, walked up the table, put a cloth pad down in front of the management folks and tried to sketch out once again what his concern was with the joint.

“And when he realized he wasn’t getting through, he just stopped.”

Showed Photos

Boisjoly said he than presented photographs that showed that charring of the secondary O-ring experienced in the cold weather flight last January had been more extensive than that experienced in the warm weather flight being used to challenge the initial assessment.

“I tried one more time with the photos,” he said. “I grabbed the photos, and I went out and discussed the photos once again, and tried to make the point again that it was my opinion from actual observation that temperature was indeed a discriminator and we should not ignore the physical evidence that we had observed.”

Here the engineer’s voice cracked again.

“I also stopped when it was apparent I couldn’t get anybody to listen,” he said. “After Arnie and I had our last say, Mr. Mason said, ‘We are going to make a management decision. He turned to Bob Lund and asked him to take off his engineering hat and put on his management hat. From this point on, management formulated the point to base their decision on.”

The executives drafted a statement saying that any tendency of the primary O-ring to move more slowly because of cold weather and fail to fill the gap would have the effect of ensuring that the secondary O-ring sealed more properly.

Banking on a Failure

They believed that gases that shot past the first O-ring would press against the second O-ring and force it to seal before the torquing of the metal joint could occur and possibly dislodge it. Under this theory, they were effectively banking on a failure in the first O-ring occurring in the first two-tenths of a second to prevent another failure at three-tenths of a second in the second O-ring.

McDonald testified that, in Florida, he continued to press his concerns about the cold weather. He said he also was worried about rough seas endangering recovery of the boosters.

He expressed skepticism about earlier testimony from top NASA officials that concerns raised by Morton Thiokol engineers had never reached the control room where the actual decision to launch was made.

“Oh, I am very surprised about that,” he said. “I hardly believe that. The issue was so controversial I thought for sure they were aware of that. I have a hard time believing they didn’t.”

Commission members, especially astronaut Sally K. Ride, pressed Thiokol executives about the rationale of the memo they signed recommending launch.

In particular, commissioners were upset that the memo appeared to ignore NASA’s 1982 declaration that the O-ring system could not be counted on as redundant.

Some of the engineers believed the rocket could be fired in temperatures as low as 31 degrees and still meet launch criteria. Others, including Lund, said they thought a 40-degree minimum was the standard.

Commission member Arthur B. C. Walker Jr., a Stanford physics professor, asked Lund how the company could recommend launching at a liftoff time forecast for 29 degrees--it actually turned out to be 38--when it was thought that 40 degrees was the minimum allowed. The question was not answered before the session was suspended.