The lofty, memorable President Reagan speech lends one to think they were instantly killed upon explosion.
I suspect a couple stayed alive until they hit the ground and the others died quickly from the blast shock.
"The discovery of the crew compartment in March was a turning point in the investigation of the accident. A sweep of the cabin illuminated disheartening evidence of the fate of the crew:
the emergency oxygen packs had been activated, indicating a high probability that the astronauts survived the apparent explosion and only perished after contact with the Atlantic Ocean. In fact, the commission would later determine, there had been no explosion at all; the shuttle broke up because of aerodynamic loads following a conflagration of gases liberated by the shuttle’s external tank.
On July 28, 1986, Rear Admiral Richard H. Truly, NASA’s Associate Administrator for Space Flight, released a report from Joseph P. Kerwin, a biomedical specialist from Houston’s Johnson Space Center commissioned to find the cause of death for the seven astronauts. Kerwin explained that each crew member’s helmet was connected to an emergency pack of oxygen called a personal egress air pack, or PEAP, which must be manually activated. Four PEAPs were recovered, he wrote, and three had been activated.
The report, which concluded that the cause of death was indeterminable, indicated that
the mid-air breakup forces were “probably not sufficient to cause death or serious injury” but that the crew “possibly, but not certainly, lost consciousness.” It also revealed that the estimated time of free-fall for the seven astronauts before their impact with the ocean was two minutes and forty-five seconds: a horrifying number to those who invested hope in a quick and painless death for the crew. And maybe it was: the compartment slammed into the ocean at a skull-cracking 207 miles per hour, an impact that would kill any human instantly. Speculators to this day go back and forth about whether the crew was conscious during the free-fall, but no conclusive evidence has ever been found."
