With new tests convincing investigators that a piece of foam insulation breaking off the space shuttle Columbia during liftoff was the eventually cause of the tragedy last February, the debate now turns to whether the crew could have been rescued.
Investigators told CBS News Correspondent Bob Orr they now believe Columbia was doomed. While the shuttle could easily orbit in space with an undetected hole in its wing, it could not return to the Earth's atmosphere.
Columbia Accident Investigation Board member Scott Hubbard said he believed the test showed that it would have been very difficult, if not impossible, to repair the foam damage during orbit.
"I feel gratified that after months of work we're able to demonstrate this connection between the foam and the damage," Hubbard said. "But, I know that it was the source of tragedy. So that makes me feel very sad."
"There could have been a rescue attempt," disagreed former astronaut Mark Brown on CBS News' Early Show Tuesday. "The $64 question is, how successful could it have been? I think it potentially could have been NASA's finest hour. We could have made a heroic effort to try to bring the crew back."
As Columbia began its fiery re-entry, hot gasses entered the breach in the wing. The three thousand degree temperatures created a blow-torch effect that melted the aluminum structure and ultimately destroyed the spacecraft, ripping the orbiter apart in the skies over Texas.
A chunk of foam insulation fired at shuttle wing parts Monday blew open a gaping 16-inch hole, yielding what one member of the Columbia investigation team said was the "smoking gun" that proves what brought down the spaceship.
The crowd of about 100 watching the test gasped and cried, "Wow!" when the foam hit — the impact so violent that it popped a lens off one of the cameras recording the event.
The foam struck roughly the same spot where insulation that broke off Columbia's big external fuel tank during launch smashed into the shuttle's wing.
At that time, reports Orr, none of cameras recording the launch picked up any damage to the wing. And, from on board the flight deck, the seven astronauts could not see the area where the foam hit.
Investigators had speculated that the damage led to the ship's destruction during re-entry over Texas in February, but Monday's test offers the strongest proof yet.
"We have found the smoking gun," Hubbard said of the seventh and final foam-impact test by the board.
"This is in fact the most probable cause creating the breach that led to the accident of the Columbia, the loss of crew and vehicle," he said.
During the simulated foam collision, a 1.67-pound piece of fuel tank foam insulation shot out of a 35-foot nitrogen-pressurized gun and slammed into a carbon-reinforced panel removed from shuttle Atlantis.
The countdown boomed through loudspeakers, and the crack of the foam coming out at more than 500 mph reverberated in the field where the test was conducted.
Sixteen high-speed cameras captured the impact, and hundreds of sensors registered movements, stresses and other conditions. The impact was so strong that it damaged one of the gauges.
"There's a lot of collateral damage," Hubbard said.
NASA will continue gathering more information about the poorly understood pieces that line the vulnerable leading edges of shuttle wings, Hubbard said.
One month ago, another carbon shuttle wing panel — smaller and farther inboard — was cracked by the impact, in addition to an adjoining seal. This time, the entire 11½-inch width of the foam chunk — rather than just a corner during previous tests — hit the wing, putting maximum stress on the suspect area.
Former astronaut Brown, who flew aboard Columbia in 1989 on a Defense Department mission, says NASA should now work to resume shuttle flights.
"I think now that we understand the cause and effect relative to the accident, we can get on with the more engineering details of what we need to do to fix the leading edge and to improve the inspection techniques and probably return to flight next year," the retired Air Force colonel told Early Show co-anchor Harry Smith.
But it's also time to start work on the next reusable space vehicle.
"Clearly we need to start a new effort to develop the next generation of access to space," Brown said. "The problem is that that's a ten-year effort, so we need to start very soon."
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