Groupthink and the Challenger explosion

By: Leon Smith - Contributing columnist
Courtesy photo The space shuttle Challenger before its 1986 explosion.

Look at the picture. There you see a monument to human ingenuity and patience — and at the same time, one to human frailty.

The solid-fuel rocket boosters are like Roman candles. They have a nose cone, a center section and a nozzle. They also have solid fuel which, when ignited, burns furiously for 73 seconds, and 28 miles — boosting the shuttle craft and its external hydrogen/oxygen rocket fuel tank nearly halfway to the Karman line, where space is said to begin, 62 miles from the Earth’s surface. They comprised 2.6 million pounds of the shuttle’s 4.1 million-pound weight.

The rocket boosters were smart, too, able to disconnect from the external tank, blast off at a vertical angle, reach maximum height to choose its landing point, then to make a parachute-assisted descent to the ocean, to be picked up, refurbished, and used again. The shuttle was designed to return to the atmosphere, then glide to earth, to land on the concrete runway at Kennedy Space Center in Florida. Only the external tank was considered expendable.

In many ways, the rocket boosters were the simplest part of a shuttle, and even though they had the temperament of a bottle rocket, these 15-story tall, 12-foot diameter boosters were completely safe, as long as they were used according to directions, because the shuttle was built in sections. Built at the Morton Thiokol facility in Utah, they were shipped by rail to Kennedy.

Notice the four sections between the nozzle and the nose cone. These are solid fuel sections, which carry 1.2 million pounds of solid fuel in each booster. These sections were assembled at Kennedy. To keep the gases from the rocket inside the rocket shell, two large O-rings and heat resistant putty were placed at each joint.

After the spent boosters were recovered and shipped back to Utah, engineers at Morton Thiokol examined the rockets for damage, giving special attention to each joint. The spent rockets from the shuttle Discovery were inspected about six months before the Challenger’s last flight.

Examining the 150 foot-long rocket, Project Engineer Roger Boisjoly noticed that seven feet of the primary O-ring in the fuel section had been ruined by the rocket’s heat. The second O-ring, though scorched, kept the gases inside the rocket.

“O-ring theory is easy,” Boisjoly said to himself. “I can use one to stop a garden hose from spewing at the point where the nozzle meets the hose. I unscrew the nozzle and place the right sized rubber washer inside. When I screw the nozzle back on, the rubber expands to fill the gap between the nozzle and the hose, and when I screw the nozzle back on, and turn on the water, the spewing stops. But if the O-ring won’t expand any more — because it dries out — the spewing starts back.”

“So, why did these O-rings fail?” he asked himself. “Something caused this O-ring to act like it was dried out.”

He suspected a cold launch, so he checked the temperature records; sure enough, the temperature on the launchpad at liftoff had been 53 degrees F. So, the rocket O-rings acted as if they were dried out. If both O-rings ever failed, the gases from the rocket fuel would spew out onto the external tank and explode, destroying the Challenger, and most probably killing the astronauts inside.

Challenger had flown nine missions without incident. There had never been an astronaut lost during a shuttle mission. But if the O-rings were not used in the right temperature, that perfect record would surely change. Boisjoly discussed the matter with his colleagues and, gaining support, he repeatedly sent memos to management. Finally Thiokol set up a task force on the problem, but gave it no money, no power to bring about change, and no management support. The task force was created, the engineers believed, not to solve the problem, but to simply keep them quiet.

The ploy did not work. The month before the Challenger was lost, Boisjoly advised his managers in writing that the O-ring problem was going to bring devastation to the shuttle program. He got no reaction, but he saved a copy of the paperwork.

When the Challenger was scheduled to fly on Jan. 28, 1986, Roger learned the temperature was forecast to be 30 degrees.

“We’ve got to stop this launch,” he said.

“It will simply blow up,” said his friend Bob Ebeling. They went to their managers, adamant that the launch had to be stopped. Their managers scheduled a teleconference with Marshall Space Center in Huntsville, Alabama, which was in charge of all rocket propulsion systems.

“What do you want me to do? Wait ‘til April?” Boisjoly remembered a Huntsville manager saying.

“You better get with the program” someone from another Thiokol plant added. “This is not a decision for engineers; it’s a decision for managers. Take off your engineer’s hat and do what you’re paid to do. Be a manager. We need to fly.”

Thiokol went offline. The Utah managers told their engineers they agreed that the flight was dangerous, but they had no data to convince Marshall they should scrap the flight.

“They want us to prove the mission will fail before they’ll stop the launch,” Boisjoly said “We can’t prove that. They’re changing the rules; we’ve never been asked to prove a mission will fail.” He paused.

“All we can do is say that in our expert opinion the mission is not safe,” he said. “And if you go ahead, we will all be sorry. Especially the astronauts.” He paused. “When an O-ring fails, it will be in the shady side rocket,” he added. “It’s colder.”

Utah management re-joined the teleconference and said they had no data to prove the mission would fail. They gave their go-ahead to launch.

Marshall polled everyone on the teleconference, but in this atmosphere, no one was willing to object.

On the day of launch, Melbourne and Orlando recorded record low temperatures — 26 degrees. By the 11:38 a.m. launch time, the temperature had risen only 10 degrees.

Afraid that the Challenger would blow up before it ever got off the ground, Boisjoly came to watch the launch in Ebeling’s office in Utah. When blastoff went perfectly, they heaved a sigh.

But three-tenths of a second into the flight, a 7.34-foot section of both shady side O-rings was vaporized by the heat from the rocket booster. Puffs of smoke came out. When the smoke stopped, Boisjoly and Ebeling sighed relief again. Miraculously, aluminum oxide from the rocket fuel had moved in to fill the gap left by the O-rings. But just then, the spacecraft was twisted by wind shear, so the guidance controls caused the craft to lurch, shattering the aluminum oxide plug in the booster rocket. Fire lept through the gap, burned through the external liquid hydrogen/oxygen tank, which exploded, leaving only a cloud of smoke that looked like a snake with two heads.

Everyone assumed the astronauts had died. For a few hours, management was contrite enough to make real changes. But soon, the cover-your-backside mode took over and NASA laid all the blame on Thiokol, who paid a relatively trivial fine — shortly after to receive another major contract, outside the newly-grounded space shuttle program.

Ebeling retired from Thiokol shortly afterward. Boisjoly developed post-traumatic stress disorder. But he took his written records to the Rogers Commission to tell the the real reason for the disaster. For this testimony, Boisjoly found himself ostracized by Thiokol, as well as his friends and neighbors who worked there. He left Thiokol — never to find work in aerospace again. And even though he spent the rest of his life encouraging ethics in science, he never got over his sorrow for a disaster that could have been avoided, and for which he blamed himself.

Pride goeth before destruction, goes the Proverb, and a haughty spirit before a fall. Thiokol and NASA, who believed they were too good to fail, failed anyway, but did not learn a lesson. Thiokol did not want to believe that there was something wrong with the design of their rocket booster. NASA did not want to hear of a launch postponement. It bespoke weakness and did not look good to Congress, who provided only year-to-year funding. Neither liked dissenting voices and wanted to maintain the illusion that their assertions were correct, and that everyone was “on board” with the decision to launch. And then, as if needing a scapegoat, the entire aerospace community placed the blame on the man who called NASA and Thiokol out.

So, someone is still responsible for the manslaughter of seven astronauts and the ostracism of Roger Boisjoly.

It has become common for power groups to trust only their own PR, believing their own spin, totally convinced they can do no wrong — despite direct evidence to the contrary — then trying to pin the blame on someone else. Pride always leads to destruction for someone.

Maybe someday these haughty decision makers, encouraging each other in pride and self-deception, will come to understand that their folly causes great suffering for their victims: like seven astronauts who may have endured nearly three minutes of free fall before their crew compartment crashed into the ocean, and an ethical mechanical engineer whose death took considerably longer.

Courtesy photo The space shuttle Challenger before its 1986 explosion. photo The space shuttle Challenger before its 1986 explosion.

Leon Smith

Contributing columnist