According to Allen J. McDonald, the Vice President of his company made a recommendation that the shuttle should not be launched in temperatures below 50 degrees F. This was a qualitative judgement, but it was based on an incident that occured about a year earlier in which heated gas had passed through the first o-ring and was stopped by the second o-ring - this was not supposed to happen. It was determined that low temperature had caused this first incident. In the Challenger disaster, according to McDonald anti-freeze was poured into an area of the shuttle which was not standard protocol.
McDonald was Director of Morton Thiokol's Solid Rocket Booster Program, which was the company that designed and built NASA's rocket boosters. His company was consulted directly by NASA the night prior to the launch. While he refused to sign-off on the launch, senior-ranking officials in his company overrode him and gave their authority to the launch.
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