[Jims5543]

Originally posted by stevepaa
That's not quite what I remember. Do you have a link? I remember the engineers warning about low temperature flight and management at NASA and higher pushing for the flight anyhow.

O-rings are tried and true, and very sucessful when used in proper tested environment. They do not work well when cold.

Neither Thiokol nor NASA expected the rubber O-rings sealing the joints to be touched by hot gases of motor ignition, much less to be partially burned. However, as tests and then flights confirmed damage to the sealing rings, the reaction by both NASA and Thiokol was to increase the amount of damage considered "acceptable." At no time did management either recommend a redesign of the joint or call for the Shuttle's grounding until the problem was solved.

The Commission has concluded that neither Thiokol nor NASA responded adequately to internal warnings about the faulty seal design. Furthermore, Thiokol and NASA did not make a timely attempt to develop and verify a new seal after the initial design was shown to be deficient. Neither organization developed a solution to the unexpected occurrences of O-ring erosion and blow-by even though this problem was experienced frequently during the Shuttle flight history. Instead, Thiokol and NASA management came to accept erosion and blow-by as unavoidable and an acceptable flight risk. Specifically, the Commission has found that:

Source:

Primarily - My memory as the company I worked for was contracted by Thiokol to help develop QC devices for future assembly. It was admitted to us and also brought out in commision hearing that it was well know the o-rings were failing on all flights not just cold weather ones. Although the cold weather did amplify the problem.

Seconday:
http://www.awesome80s.com/Awesome80s/Tech/Space/Shuttle/Challenger_Tragedy/Presidential_Report_Part3.asp