Just finished watching a good program on National Geographic about the Challenger. In fact, it leaves you with the knowledge that NASA received indications from at least three of the astronauts' oxygen tank readers that they had been activated (something like that). It's common acceptance that they were alive as the command module was in freefall to the ocean...which took about 2 minutes. They also believe that in that fall, all on board at some point became unconscious.
Excellent commentary on what exactly transpired with the O-ring problem and how it sealed the fate of that awful day.