‘Challenger: The Final Flight’ Trailer Retraces Tragic 1986 NASA Mission That Never Made It to Space

I read a interesting piece on those 'O-ring seals' that failed and caused the explosion.

The day before the launch the temperature was below freezing. After several delays prior there was great pressure for a launch. The NASA director knew about the temperature and possible effects on the rockets but wanted written clearance from the contractor that built them that it was safe for launch.

The contracted engineers KNEW that freezing temperatures the night before would be problematic for the seals and could crack from temperature changes, they wouldn't sign a form informing NASA that it was safe.

The companies management however, was concerned that if they didn't sign and were viewed as overcautious by NASA, they would lose out on future contracts. All the companies management, except one, signed off on the launch.

Lapham's quarterly : Disaster