The seven astronauts who died when Space Shuttle Columbia exploded in 2003 never had a chance, according to a report written at NASA's request.
The ship depressurized "so rapidly that the crew was incapacitated within seconds," the report says, meaning that no one was conscious by the time the shuttle disintegrated in the skies over Texas.
But there may be useful lessons to be learned about the design of future spacecraft, says the report, which NASA is releasing today in response to a Freedom of Information Act request from news agencies.
It has been nearly six years since Columbia, coming in for a landing after a 16-day flight, broke up about 40 miles over eastern Texas.
Investigators concluded that the shuttle was damaged on liftoff by debris that had fallen from its external fuel tank, making a gash in the shuttle's wing and allowing the hot gases created on re-entry to blow the ship apart.
The new report says the accident clearly was "not survivable." But it identifies "lessons to be learned about how to improve crew survival in the future."
First, it says, the orange pressure suits worn by the astronauts were added as an afterthought after the shuttle Challenger was lost in 1986.
As a result, they were not completely "integrated" with shuttle systems and the astronauts could not keep their visors closed for the entire re-entry, because oxygen they would otherwise breathe would build up in the shuttle cabin. Pure oxygen is a fire hazard, which is why NASA tries to keep concentrations down.
The report says all seven of the astronauts' helmets were found with the visors up. With the visors in the up position, the crew were left open to the effects of depressurization, rendering them unconscious.
The panel says the Columbia crew had about 40 seconds between loss of control and depressurization of their cabin. One astronaut was not wearing a helmet, and three had not yet put on their gloves in preparation for landing.
Even if the suits had been pressurized at the moment the ship broke up, the astronauts were thrown around so violently that they would have died quickly. Their helmets were large and roomy -- inadequately protecting their heads -- and their seat belts did not automatically retract to hold them in their seats. The suits were not expected to protect an astronaut more than about 20 miles above Earth -- different suits are worn for spacewalks in orbit -- or in airspeeds higher than about 650 miles an hour.
The crew compartment, says the report, did not immediately come apart. About 35 minutes passed before debris began hitting the ground.
The report even finds fault with the parachutes the astronauts wore, which would only open if the astronauts were conscious and able to pull the rip cords.
The review committee points to improvements that might be made in future spacecraft, particularly the Orion capsule that is expected to replace the shuttles in the next decade.
"Only by learning these lessons, and ensuring that we continue the journey begun by the crews" of the lost spacecraft, the report says, "can we give meaning to their sacrifice and the sacrifice of their families."