Allan McDonald, who directed the booster rocket project at NASA contractor Morton Thiokol, urged delaying the launch of the space shuttle before it exploded in 1986. He has died at age 83.

Transcript

SCOTT DETROW, HOST:

We are remembering someone who played a major role in the fatal launch of the space shuttle Challenger. Allan McDonald died Saturday in Ogden, Utah, at age 83. He was one of the people who tried to stop the launch and later exposed an apparent cover-up. Howard Berkes has this remembrance.

HOWARD BERKES, BYLINE: On January 27, 1986, Allan McDonald stood at the cusp of history. Sign the form, he believed, and he'd risk the lives of seven astronauts set to board the space shuttle Challenger. Refuse to sign, and he'd risk his job, his career and the good life he built for his wife and four children.

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ALLAN MCDONALD: That was a reason I was at the Cape, as it required that a senior official be at the Cape to approve or disapprove a launch if something came up. And I made the smartest decision I ever made in my lifetime. I refused to sign it. I just thought, we're taking risks we shouldn't be taking.

BERKES: McDonald worked for NASA contractor Morton-Thiokol and was responsible for the two massive rockets filled with explosive fuel which lifted shuttles toward space. Hours before his decisive moment, the forecast called for 18 degrees, the coldest launch ever. His engineers knew that rubber O-rings, seals that contain burning fuel, stiffened in cold weather and didn't seal, which is precisely what happened. Seven lives were lost.

MARK MAIER: There are two ways in which Al's actions were heroic.

BERKES: Mark Maier directs a leadership program at Chapman University and has studied the Challenger launch decision.

MAIER: One was on the night before the launch, refusing to sign off on the launch authorization and continuing to argue against it. And then afterwards, in the aftermath, exposing the cover-up that NASA was engaged in.

BERKES: A presidential commission investigated the Challenger disaster. And during a closed hearing, McDonald was shocked when a NASA official glossed over a fundamental fact. The Thiokol engineers vigorously opposed the launch and formally recommended a delay, but they were overruled under pressure from NASA by Thiokol executives who signed the launch authorization McDonald refused to sign.

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MCDONALD: I was sitting there thinking, that's about as deceiving as anything I ever heard. So I raised my hand. I said, I think this presidential commission should know that Morton-Thiokol was so concerned, we recommended not launching below 53 degrees Fahrenheit. And we put that in writing and sent that to NASA. I'll never forget Chairman Rogers said, would you please come down here on the floor and repeat what I think I heard?

BERKES: The investigation shifted to the O-rings, to the Thiokol engineers and to NASA's refusal to listen. McDonald was demoted for speaking up until members of the commission and Congress intervened. They vowed Thiokol would never get another federal contract, so the company relented. And McDonald supervised the redesign of the booster rocket joints that had failed. Mark Maier of Chapman University.

MAIER: What we should remember about Al McDonald - he would often stress his laws of the seven Rs. And it was always, always do the right thing...

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MCDONALD: ...For the right reason at the right time with the right people, and you will have no regrets for the rest of your life. And it's really that simple if you just keep it focused that way.

BERKES: Allan McDonald said he had no regrets. On the 30th anniversary of the Challenger tragedy, he cited another favorite quote. Regret for things we did is tempered by time, he said. But regret for things we did not do is inconsolable. For NPR News, I'm Howard Berkes.

(SOUNDBITE OF OLAFUR ARNALDS'S "PARTIAL") Transcript provided by NPR, Copyright NPR.

Tags: challenger disaster  space shuttle