The Post said NASA told the Columbia accident investigation board it now believes it could have kept the damaged shuttle in orbit as long as 30 days, enough time to attempt a rescue mission described as "iffy" and hinging on a nexus of favorable conditions.

On Friday, the head of the investigative team, retired Admiral Harold Gehman Jr., said the NASA rescue scenario involved a four-man crew aboard the Atlantis, a sister shuttle that was being prepared for a subsequent mission and could have been rushed into service.

According to the Post's account, NASA said the Atlantis would have maneuvered itself into a parallel orbit 50 to 90 feet (15 to 27 meters) away from Columbia.

Tethered rescuers from Atlantis would have floated to the damaged Columbia with sufficient spacesuits and retrieved the seven crew members. Columbia carried only two such suits.

In an even less likely scenario, NASA would have instructed Columbia crew members to don the two spacesuits and attempt to repair damage to the craft's left wing incurred during launch, when the wing was hit by a piece of insulation from a jettisoned external fuel tank.

It was that damage to the shuttle's heat shields that caused the spacecraft to disintegrate on re-entering Earth's atmosphere.

The investigation board earlier this month had asked NASA for an assessment of the disaster, which it delivered in Houston on Friday.

In describing the rescue scenarios, Gehman said they were "technically possible, very, very risky, and a whole bunch of 'ifs' had to line up in the 'yes' column," the Post reported.

SPACE.WIRE