Wow:

The previous evening Boisjoly and Ebeling had spent six hours in teleconference with Nasa managers arguing that the Challenger launch should be delayed. The two men had been told that the temperature in Florida was plummeting to below freezing and had been instantly concerned about whether their rockets would perform properly in such conditions.

They appeared to be winning the argument - until their own managers turned against them and gave Nasa the recommendation they appeared to want: to launch.

Boisjoly was persuaded by Ebeling to watch the TV that fateful morning of January 28 1986. He sat on the floor in front of the screen resting his back against the legs of the older man. When the clock reached T minus five seconds the two engineers held hands and braced themselves for an explosion. But to their immense relief Challenger cleared the launch pad. "I turned to Bob and said 'we've just dodged a bullet,' because it was our expectation it would blow up on the pad."

The two men began to relax. But then, at 73 seconds, the heart-stopping plume of white smoke suddenly filled the screen. "There was silence for the longest time," says Boisjoly. "Then I went to my office, sat facing the wall and tried to hold back my emotions."

[via Lake Effect where Dan offers insightful thoughts on why this is important for a great many reasons].