In fact the O-rings were never working as designed in the first place and NASA (but not necessarily those astronauts personally) knew it from the start. This w

In fact the O-rings were never working as designed in the first place and NASA (but not necessarily those astronauts personally) knew it from the start. This was recognized early on in the program before the Shuttle ever flew. Those SRB joints were originally meant to have two O-rings as redundancy. But in testing they found that the first O-ring was being extruded, pushed past where it was meant to be into the joint and some hot gases were getting past it, meaning the second O-ring was no longer redundant. It was then determined that 'This is Fine'; instead of changing the design they changed the designation of the second o-ring to acknowledge that it was no longer redundant. They flew with that arrangement even though they already knew the primary O-rings didn't function correctly.