By Marcia Dunn
The Associated Press

CAPE CANAVERAL, Fla. - If liftoff damage to Columbia's thermal tiles caused the disaster, was the crew doomed from the very start? Or could NASA have saved all or some of the seven astronauts by trying some Hollywood-style heroics - a potentially suicidal spacewalk, perhaps, or a rescue mission by another shuttle?

Some of the ideas would have been highly impractical, dangerous and perhaps futile.

The shuttle does not carry spare tiles, and NASA insists there was nothing on board that the crew could have used to repair or replace missing or broken ones.

In any case, the space agency believed at the time that the tile damage was nothing to worry about.

Still, as James Oberg, a former shuttle flight controller and author who has been bombarded by "Armageddon"-type rescue ideas via e-mail, said Sunday: "They may be implausible, but not by much." He added: "There's always the question of miracles."

NASA knew from day two of Columbia's 16-day research mission that a piece of the insulating foam on the external fuel tank peeled off just after liftoff and struck the left wing, possibly ripping off or damaging some of the tiles that keep the ship from burning up when it re-enters Earth's atmosphere.

Engineers spent days analyzing the situation and concluded that there was no reason for concern. The flight director in charge of Columbia's Jan. 16 launch and Saturday's descent from orbit, Leroy Cain, assured reporters as much on Friday.

But hours after the disaster, shuttle program manager Ron Dittemore acknowledged that NASA might have been wrong and that wing damage on launch day might have contributed to or even caused Columbia to disintegrate.

"It's one of the areas we're looking at first, early, to make sure that the investigative team is concentrating on that theory or that set of facts as we are starting to unfold," NASA Administrator Sean O'Keefe said Sunday.

Some facts remain:

NASA did not attempt to examine Columbia's left wing with high-powered telescopes on the ground, 180 miles below, or with spy satellites. The last time NASA tried that, to check Discovery's drag-chute compartment during John Glenn's shuttle flight in 1998, the pictures were of little use, Dittemore said. Besides, he said, "there was zero we could have done about it."

Similarly, NASA did not ask the crew of international space station to use its cameras to examine the wing

NASA did not consider a spacewalk by the crew to inspect the left wing. The astronauts are not trained or equipped to repair tile damage anywhere on the shuttle, least of all on a relatively inaccessible area like the underside of a wing, Dittemore said.

Could NASA have sent another shuttle to rescue Columbia's five men and two women?

In theory, yes.

Normally, it takes four months to prepare a shuttle for launch. But in a crisis, shuttle managers say they might be able to put together a launch in less than a week if all testing were thrown out the window and a shuttle were already on the pad.

Columbia had enough fuel and supplies to remain in orbit until Wednesday, and the astronauts could have scrimped to stay up another few days beyond that. With shuttle Atlantis ready to be moved to its pad, it theoretically could have been rushed into service.

Could Columbia's astronauts have abandoned ship and boarded the international space station?

Because Columbia was in an entirely different orbit than the space station, it did not have enough fuel to fly to the orbiting outpost. Even if the shuttle could have limped there, it could not have docked.

Columbia was not equipped with a docking ring since it was never meant to go there. So the shuttle astronauts would have had to float over in spacesuits to get there.

Could Columbia's astronauts gone out of a spacewalk to inspect and perhaps repair their own ship?

Two of Columbia's astronauts, Michael Anderson and David Brown, were trained to do a spacewalk, and they had the suits to do it.

But neither was trained to do anything more than a relatively simple emergency repair, like freeing a stuck radio antenna or fixing a jammed latch that could cause the ship to burn up during re-entry.

Moreover, a spacewalk to reach the underside of the wings could be suicidal, because there is nothing to hold on to, and the astronauts did not have mini-jetpacks to propel themselves. The astronauts could have floated off and never gotten back to the shuttle.

In theory, NASA could have had the shuttle descend through the atmosphere at a much shallower angle in hopes of relieving the heat on the ship.

But that could have life-threatening dangers, too. That kind of a flight profile almost certainly would have had the shuttle coming in too fast for a safe landing.

If it was determined that there was no way Columbia and crew could survive a re-entry, and another spacecraft could not reach them in time, they would have been stuck in orbit for a couple of months before being dragged down through the atmosphere in a fireball.

"It would be visible at dawn and dusk and that would be pretty creepy," Oberg said. "But on the other hand ... It would be a Viking funeral."