User:Electronsoup/sandbox

Crew survivability aspects
In 2008, NASA released a detailed report on survivability aspects of the Columbia reentry. In 2014, NASA released a further report detailing the aeromedical aspects of the disaster. The crew were exposed to five lethal events in the following order:

Depressurization
After the initial loss of control, Columbia's "cabin pressure was nominal and the crew was capable of conscious actions". During this period the crew attempted to regain control of the shuttle. As Columbia spun out of control, aerodynamic forces caused the orbiter to yaw to the right, exposing its underside to extreme aerodynamic forces and causing the orbiter to break up. Depressurization began when the shuttle forebody separated from the midbody 41 seconds after loss of control. The crew module pressure vessel was penetrated when it collided with the fuselage, and the "depressurization rate was high enough to incapacitate the crewmembers within seconds so that they were unable to perform actions such as lowering their visors." The crew lost consciousness, suffering massive pulmonary barotrauma, ebullism and cessation of respiration.

Off-nominal dynamic G environment
The shuttle's separated nose section rotated unsteadily about all three axes. The crew (now unconscious or deceased) were unable to brace against this motion, and were also harmed by aspects of their protective equipment:


 * Lack of upper-body and arm/leg restraints: the crew's torsos were free to move because "the strap velocity was lower than the locking threshold velocity of the inertia reel system" and because the seat restraints did not prevent lateral movement. Fractures consistent with flailing arms and legs were also observed.
 * Non-conformal helmets: unlike a racing helmet, the ACES suit helmets allowed the crew's heads to move inside the helmet, causing blunt force trauma during collisions. The helmet neck ring acted as a fulcrum for cervical vertebrae fractures as the skull whipped backwards, as well as inflicting jaw injuries when wind blasted the helmet off.

Separation of the crew members from the crew module and the seats
As the crew module disintegrated, the crew received lethal trauma from their seat restraints and were exposed to the hostile aerodynamic and thermal environment of re-entry, as well as molten Columbia debris.

Exposure to high-speed / high-altitude environment
After separation from the crew module, the deceased crewmembers entered an environment with "lack of oxygen, low atmospheric pressure, high thermal loads as a result of deceleration from high Mach numbers, shock wave interactions, aerodynamic accelerations, and exposure to cold temperatures." NASA stated that despite not being certified for those conditions, the ACES suit "may [have been] potentially be capable of protecting the crew," had the suits not already been destroyed by the cabin's thermal environment during breakup.

Ground impact
The crewmembers had lethal-level injuries sustained from ground impact. The official NASA report omitted some of the more graphic details on the recovery of the remains; witnesses reported finds such as a human heart and parts of femur bones.

All evidence indicated that crew error was in no way responsible for the disintegration of the orbiter, and they had acted correctly and according to procedure at the first indication of trouble. Although some of the crew were not wearing gloves or helmets during reentry and some were not properly restrained in their seats, doing these things would have added nothing to their survival chances other than perhaps keeping them alive and conscious another 30 or so seconds.