Last-Ditch Effort To Save Shuttle?

An attempt may have been made to override Columbia's autopilot in the final few seconds of its doomed flight, according to information received Sunday by the space shuttle's accident investigation board.

But, as an official close to the investigation stressed: "The data are really suspect. They can't ensure the integrity of any of the data, and some of the stuff that they're saying may be inaccurate or misinterpreted."

Ongoing analysis of the final two seconds of telemetry during re-entry shows the doomed ship's fuselage, crew module, right wing and right-side rocket pod were essentially intact 32 seconds after the commander's final transmission and that the orbiter's digital autopilot was still flying the spacecraft when data finally stopped flowing, reports CBS News Space Consultant Bill Harwood.

By that point, however, there was nothing the crew could have done to stop the quickening disaster. The telemetry shows Columbia's left wing and left-side orbital maneuvering system rocket pod were either gone or severely damaged, the ship's hydraulic system was empty, its flash evaporator cooling system was in shut down and multiple computer alarms were being generated because of lost data from the orbiter's left side orbital maneuvering system rocket pod.

A NASA spokeswoman, Eileen Hawley, said the possible attempted override could have been unintentional; in other words, one of the pilots may have bumped the stick.

But one of the crew may have tried to take over the space shuttle before its destruction above Texas on Feb. 1.

Future shuttle commander Scott Kelly told CBS News Correspondent Peter King he is pretty sure that is what happened.

"He was probably focusing in on what he was trained for," he said, "and that is to respond to whatever malfunctions they had in the best way that he could."

For weeks, in an attempt to reconstruct what went wrong during Columbia's re-entry, NASA and other experts have been analyzing data that were transmitted in the final 32 seconds of flight. The last two seconds of data, which follow 25 seconds of nothing, indicate that there was an input to disengage the autopilot system, the official said.

The data also suggest that the four steering jets that automatically began firing to try to compensate for the increased drag on the left side of the spacecraft were no longer able to counteract the forces, the official said. A breach in the left wing, which allowed hot gases to penetrate, is suspected for the cascade of catastrophic events.

"It kind of indicates the orbiter was out of control, basically," the official said.

Guidance and navigation data show the shuttle was in an "uncommanded" orientation, yawing rapidly to one side, presumably toward Earth, in what may have been the start of a banking tumble, reports Harwood. The yaw rate — a measure of how fast Columbia's nose was swinging to one side — was at least 20 degrees per second, the maximum value the sensors are designed to measure. The actual yaw rate may have been higher.

The autopilot never went off, the official close to the investigation noted, possibly because there was not enough time for it to do so — or perhaps because there was no attempt by the crew to override it.

"Had you had more data after two seconds, you might know whether it would have gone off or not," the official said. It is difficult if not impossible to know, with certainty, "whether that was unintentional or whether it was intentional or whether it even occurred at all," the official said.

Hawley pointed out that even before Columbia started re-entering the atmosphere, commander Rick Husband accidentally bumped the stick but quickly corrected for it.

Minutes later, "there is some evidence that the stick may have been bumped" again, Hawley said. But she added that part of the problem is that the data are intermittent, with a high error rate, "and to draw any conclusions from it would be really wrong."

At 8:59 a.m., Husband called Houston, presumably to report or confirm a computer fault message showing lost pressure from both left-side main landing gear tires.

"Roger, uh, buh..." he radioed, but he was cut off.

Engineers now say that final transmission was interrupted not because of the mounting problems on board the shuttle, but because the line of sight between a forward antenna cluster and the NASA communications satellite then in use was blocked by Columbia's vertical stabilizer and aft engine compartment.

No data was received from Columbia for 25 of the craft's final 27 seconds because of the blockage.

The data also suggest there were no readings coming from Columbia's left orbital maneuvering system in the final two seconds, which could mean it broke off or was badly damaged along with the left wing, said the official close to the investigation.

Engineers now believe the main body of the spacecraft did not begin breaking up until nearly 20 seconds after the final two-second burst of telemetry. Vehicle breakup was preceded by the separation of at least three major pieces of debris beginning around 9:00:02 a.m., at almost the same instant the final two seconds of telemetry began flowing back to Earth after a 25-second data dropout.

NASA is reconstructing, as best it can, the timeline of Columbia as it flew across the Pacific, crossed the California coast and continued its descent over Nevada and New Mexico and Texas, en route to a Florida touchdown following a 16-day science mission. All seven astronauts were killed.

The board, meanwhile, suspects that the searing gases of atmospheric re-entry probably entered the shuttle through a breach along the leading edge of the left wing. The blowtorch-like gases may have snaked their way through the wing and streamed out the left main gearing landing compartment.

Earlier in the investigation, the board believed the gases may have entered this left wheel well, but is more inclined now to think the gases were actually coming out, the official said.

"It's a strong theory. It has a certain amount of support," the official said.

The board is still trying to determine whether launch debris caused the breach. Insulating foam or other debris broke off Columbia's external fuel tank barely a minute into the flight on Jan. 16 and struck the left wing.

NASA engineers reportedly suggested there might have been a problem. Should the shuttle crew have been alerted? Kelly says yes.

"I would want to know that we were in grave danger," he said.

Kelly is scheduled to command one of the first missions after NASA returns to flight, but he said the Columbia accident hasn't changed his attitude.

"Flying in space is a risky business. It's always been risky. After this accident, it will remain risky," he said. "Granted this accident makes it a little more real than just a probability and statistics problem."

Kelly, however, said he believes the cause will be found and fixed.

His brother Mark is also an astronaut, but neither is seeking a new career.

"We haven't talked about that because it's something that I don't think either of us have thought of," he said.

But their parents have suggested it.

"I just laugh," he said, because there is nothing he would rather be doing, risks and all.

CBS News Space Consultant William Harwood has covered America's space program full time for more than 15 years, focusing on space shuttle operations, planetary exploration and astronomy. Based at the Kennedy Space Center in Florida, Harwood provides up-to-the-minute space reports for CBS News and regularly contributes to Spaceflight Now and The Washington Post.