From The Huffington Post:
On January 27, 1986, the night before the Space Shuttle Challenger was to be launched, a phone conference took place between NASA managers and Morton Thiokol, the manufacturer of the shuttle’s solid rocket motors. Engineers from the rocket company told NASA that it would be too cold (26ºF) to launch since the previous coldest launch (53ºF) showed burn-through problems with the O-ring seals and therefore there was no data to show that it was safe to launch. The NASA managers asked if they could prove that the rockets would fail at low temperatures and, of course, it could not be proved. NASA then held a private call with the rocket company’s managers, with the engineers excluded, and got them to agree to say it was OK to…