I like to consider myself fairly well read on the Challenger disaster, yet tonight I've just had my world view rocked...!
The rocking comes from 2 facts.
Firstly, Challenger did NOT explode. Yes, I know - what has everyone been saying for the past 3 decades?! The truth is, the booster rocket imploded, the fuel ignited, and STS Challenger ripped apart, with the tail and engine coming off the body, and payload ripping off the crew compartment. They did not however "explode" - it was a physical reaction to the stresses involved. Now, that's the good news.
Secondly, and pretty horrifically... I'd always thought that it was believed that the crew died "instantly". That was in part revised after the Captain was confirmed to have said "Uh oh" about 3 seconds into the incident. The theory thus remained - the crew were likely dead moments after the booster's fuel rapidly ignited and tore the craft apart. However, when the crew compartment was recovered (also news to me) with the crew's bodies on board, 4 of them had activated their emergency air supply units. This suggests that at least some of the crew survived the initial disaster, and were conscious long enough to follow emergency protocols.
In all likelihood they would have apparently passed out before the crew compartment hit the Atlantic Ocean, but ultimately autopsies could not verify when death occurred.
Anyways, just had to share this shocking multiple decade long non secret.