India, April 4 -- For 30 years, until his death in 2016 (aged 89), Bob Ebeling lived with a crippling kind of regret.

If he had stood his ground, it is likely the Challenger space shuttle would not have taken off, exploded, and killed all seven people on board.

The booster-rocket engineer with Morton Thiokol, a contractor for NASA, was among those who tried to stop the mission on the night before its launch, in 1986. He and a group of engineers were concerned that the rubber seals around the rocket booster might not hold in the 2-degree-Celsius temperatures in Florida that week, which were then the coldest conditions in space-shuttle history.

Eventually, under mounting pressure, they withdrew their objections, allowing the launch to pr...