Engineer who warned of 1986 Challenger disaster still racked with guilt, three decades on

BRIGHAM CITY, Utah, Jan. 28 (UPI) -- As the entire nation watched in stunned silence as the Space Shuttle Challenger abruptly blew apart 73 seconds after launch, one man couldn't keep his eyes anywhere near the screen. For days by that point he'd tried exhaustively to get STS-51-L grounded -- and decades of reflection have done nothing to shake his belief that he's personally responsible for the worst disaster in the history of the American space program, which occurred exactly 30 years ago Thursday.

The problem was, no one with any authority listened to Bob Ebeling.

An engineer at Morton Thiokol, the Utah-based rocket propulsion firm awarded the $800 million contract in 1973 to build the shuttles' solid rocket boosters, Ebeling repeatedly warned NASA administrators that the launch conditions that day could be catastrophic.

Somebody should have listened.

Years after the disaster, it was learned Challenger was doomed by a failed rubber seal, called an O-ring, that lined the field joints of the boosters. They are designed to flex during launch movement and prevent fuel from escaping -- and igniting -- but in the chilly Florida air that morning a seal on the lower right booster wouldn't flex. Too cold. Unable to do its job, the ring was also burned away by combusting fuel during liftoff -- producing small, pulsing black wisps of smoke that can be seen in footage of the launch.

Today, Ebeling, 89, says he was fully aware of the ring's failure potential and tried to get NASA to take him seriously, to wait for warmer weather. Instead, he was overruled -- by managers at both the space administration and Thiokol.

"I was one of the few that was really close to the situation," Ebeling told National Public Radio this week. "Had they listened to me and wait[ed] for a weather change, it might have been a completely different outcome."

Although Ebeling cannot be accused of neglect or failing to act, he says he still feels responsible for the deaths of six American astronauts and a civilian teacher aboard the flight -- even now, 30 years later.

"It's going to blow up"

By the time Challenger finally launched on the morning of Jan. 28, 1986, it had already been delayed six times in the previous week. The reasons varied between mechanical and meteorological, but the postponements may have made NASA more eager to get the late shuttle into its position in low Earth orbit. The temperature that morning was 15 degrees colder than the weather of any other shuttle launch.

"NASA ruled the launch," Ebeling said. "They had their mind set on going up and proving to the world they were right and they knew what they were doing. But they didn't."

Before he went to sleep on the night of the 27th, he'd remarked to his wife, Darlene, "It's going to blow up."

The first few moments of the Tuesday morning launch were actually met with sighs of relief from Ebeling and four of his concerned colleagues at Thiokol, for they actually believed that if an O-ring ever failed it would destroy the shuttle on the launch pad. But by an incredible stroke of luck, Challenger escaped that fate and managed to climb into the sky.

Watching the televised launch from their firm's northern Utah headquarters, the relieved engineers believed for a full 72 seconds that they, NASA and the astronauts had all dodged a catastrophic bullet -- until the moment mission controller Richard Covey relayed a command from the Johnson Space Center in Houston to Challenger pilots Dick Scobee and Michael Smith to go to full power.

"Challenger, go at throttle-up."

In what became the crew's final transmission to the ground, Scobee acknowledged.

"Roger, go at throttle-up."

Three seconds later, Ebeling and the other engineers realized in agony that their collective exhale had been premature. Challenger, soaring at a speed of nearly Mach 2, was enveloped in an incredible explosion and disintegrated in full view of hundreds at Cape Canaveral and millions more watching on national television.

"We have a report by the flight dynamics officer that the vehicle has exploded," NASA's public broadcast voice said moments later.

Date and time -- 11:39 a.m. EST, January 28, 1986. The darkest moment in American space exploration had arrived.

That evening, President Ronald Reagan sought to comfort a saddened nation with one of his most indelible and oft-quoted speeches.

"The future doesn't belong to the faint-hearted, it belongs to the brave. ... We will never forget them, nor the last time we saw them, this morning, as they prepared for their journey and waved goodbye and 'slipped the surly bonds of Earth' to 'touch the face of God.'"

They almost survived

As it turned out, Ebeling had been right. Challenger never should have been launched that morning. And once it did, in fact, it never should have made it off the pad.

The presidential Rogers Commission -- led by former U.S. Attorney General William P. Rogers and including former astronauts Neil Armstrong, Sally Ride and Chuck Yeager-- later concluded that the shuttle survived for more than a minute after the booster's main O-ring failure, and by a simple quirk of fate. Propellant at the breached field joint didn't begin pouring out when the spacecraft was on the launch pad because a buildup of metallic residue in the solid rocket fuel, called slag, had lodged there and inadvertently plugged the leak.

Engineers speculated in the years that followed that if the slag had continued to stem the leak -- for even just a few more moments -- the shuttle and her crew of seven almost certainly would have have survived. The shuttle was less than a minute from shedding both boosters.

What caused the temporary plug to fail after about 70 seconds was, again, weather-related.

Thirty-seven seconds into its ascent, Challenger encountered severe wind shear -- abrupt changes in wind speed and direction that jarred the shuttle from side to side. The sharp winds created exaggerated movements in the booster joints that dislodged the slag and finally allowed fuel to escape.

The commission called it an "accident rooted in history," in that the disaster grew from a faulty O-ring design made worse as both NASA and Thiokol first failed to recognize it as a problem, then failed to fix it and finally treated it as an acceptable flight risk.

"NASA did not accept the judgment of its engineers that the design was unacceptable. ... Thiokol's stated position was that 'the condition is not desirable but is acceptable,'" the report stated.

The disaster caused NASA to shutter the program until 1988, but Challenger would not be the last shuttle to meet with catastrophe.

Seven more astronauts were killed aboard Space Shuttle Columbia at the conclusion of mission STS-107 in February 2003. In that case, though, the problem wasn't a rocket booster -- but a piece of foam that broke away from the main center tank during launch and punched a hole in the leading edge of the left wing.

It was critical mishap. Beneath the wing and the entire shuttle are thermal tiles that resist the inferno of penetrating Earth's atmosphere during re-entry. The gaping hole in Columbia's wing was present for the entire two-week mission, but went undetected by the astronauts and mission controllers.

"I should have done more"

The tragedies of Challenger and Columbia took their toll on the American space program and the Utah aerospace manufacturer. NASA finally retired its space shuttle program in 2011 and Thiokol, which was given most of the blame for Challenger's demise, went out of business in 2007. Ebeling, though, says he won't ever be able to put away his feelings of sorrow and guilt.

For years, the Brigham City, Utah, resident was afraid to speak out about his warnings to NASA during that cold January week in 1986, fearful that he would lose his job. After three decades he concluded, "The truth has to come out."

Ebeling retired from Thiokol not long after the Challenger disaster and settled into a deep depression that would persist for decades. A religious man, the fates and families of Scobee, Smith, Ronald McNair, Ellison Onizuka, Judith Resnik, Gregory Jarvis and Christa McAuliffe have never been far from his prayers.

"I could have done more. I should have done more," Ebeling said in 1986. Today, a full 30 years later, the passage of time -- and the evident fact that he is owed no culpability -- hasn't done anything to heal the wounds he's inflicted upon himself for the Challenger catastrophe. He still feels that his attempts to persuade NASA were ineffective, his arguing of data insufficient, and his failure to stop the launch unacceptable.

"I think that was one of the mistakes that God made," he said. "He shouldn't have picked me for the job. But next time I talk to him, I'm gonna ask him, 'Why me? You picked a loser.'"