Cause and time of death
During vehicle breakup, the robustly constructed crew cabin detached in one piece and slowly tumbled. NASA estimated separation forces at about 12 to 20 times the force of gravity (g) very briefly; however, within two seconds, the forces on the cabin had already dropped to below 4 g, and within ten seconds the cabin was in free fall. These forces were likely insufficient to cause major injury. At least some of the astronauts were likely alive and briefly conscious after the breakup, because three of the four Personal Egress Air Packs (PEAPs) on the flight deck were found to have been activated. Investigators found their remaining unused air supply roughly consistent with the expected consumption during the 2 minute 45 second post-breakup trajectory. Whether the astronauts remained conscious long after the breakup is unknown, and largely depends on whether the detached crew cabin maintained pressure integrity. If it did not, time of useful consciousness at that altitude is just a few seconds; the PEAPs supplied only unpressurized air, and hence would not have helped the crew to retain consciousness. The crew cabin hit the ocean surface at roughly 334 km/h (207 mph), causing an instantaneous deceleration of over 200 g, far beyond the structural limits of the crew compartment or crew survivability levels.[9]
