Boisjoly and other engineers were alarmed the night before the scheduled Challenger launch. Freezing temperatures were forecasted. Cold weather could cause the joint design problem to worsen (because the rubber O-rings would not quickly return to their proper shape).
Participating in a conference with company and NASA officials the night before launch, Boisjoly and others expressed their concerns. They warned Morton Thiokol and NASA not to launch the shuttle on the 28th. Later, testifying about the conference before Congress, Boisjoly said:
I...grabbed the photographic evidence showing the hot gas blow-by comparisons from previous flights and placed it on the table in view of the managers and somewhat angered, admonished them to look at the photos and not ignore what they were telling us; namely, that low temperature indeed caused significantly more hot gas blow-by to occur in the joints. I received cold stares...with looks as if to say, 'Go away and don't bother us with the facts.' No one in management wanted to discuss the facts; they just would not respond verbally to...me. I felt totally helpless at that moment and that further argument was fruitless, so I, too, stopped pressing my case.
As a Presidential Commission (headed by William P. Rogers) investigated the tragedy, Nobel-Laureate Dr. Richard Feynman (one of the world's most science lecturers) pointedly discussed (during a televised hearing) his O-ring concerns with a responsible official (Larry Mulloy):
I took this stuff that I got out of your seal and I put it in ice water, and I discovered that when you put some pressure on it for a while and then undo it, it does not stretch back. It stays the same dimension. In other words, for a few seconds at least and more seconds than that, there is no resilience in this particular material when it is at a temperature of 32 degrees.
In a speech about his efforts to delay Challenger's launch, Boisjoly tells what he did after the conference call.
I wrote the following entry in my notebook after returning to my office. "I sincerely hope that this launch does not result in a catastrophe."