NASA Administrator Sean O'Keefe, his voice rising in exasperation during a congressional hearing, insisted that concerns by some senior engineers about risks of serious heat damage to Columbia's left wing — which turned out to be hauntingly prescient were handled appropriately, even though they never were passed up to NASA's top brass.
"Based on what I can see, the vetting of all this information that occurred on orbit during the operational mission was handled by the individuals, they vetted those questions, satisfied themselves there were solutions that could be found and determined if there was a safety-of-flight risk attendant to that, and determined there was not, in their judgment," O'Keefe said.
E-mails that NASA disclosed Wednesday showed senior engineers worried a day before the Columbia disaster that the shuttle's left wing might burn off and cause the deaths of the crew, a scenario remarkably similar to the one investigators believe actually occurred on Feb. 1.
The dozens of pages of e-mails describe a broader, internal debate than previously acknowledged about the seriousness of potential damage to Columbia from a liftoff collision with foam debris from its central fuel tank. Engineers never sent their warnings to the National Aeronautics and Space Administration's brass.
The chairman of the House Science Committee, Sherwood Boehlert, R-N.Y., asked O'Keefe whether he was confident the engineers' concerns moved up the chain of command to the appropriate management level.
"Indeed," O'Keefe responded, but he added that he would defer to the independent review board's views on that question.
Rep. Anthony Weiner, D-N.Y., questioned O'Keefe aggressively about why NASA didn't reveal these e-mails earlier than yesterday. O'Keefe has said he did not read the messages until Wednesday. Weiner was so animated during the congressional hearing that he eventually apologized "for being a little hot under the collar."
"Why was it that even if there was hint of a footnote of a memo on a scrap of an envelope that was within this investigation's scope, that it only made its way to you yesterday, at the same time it made its way to everyone else on the AP wire," Weiner asked. "This is stunning to me that this is the process being followed. That's crazy. You must have gotten these memos and hit the roof. Is that a fair characterization?"
O'Keefe said NASA was releasing relevant information about Columbia — to the public, to the board investigating the accident and to news organizations — as quickly as it is found, "without any filtering from me."
"I certainly am not privy to every single one of those deliberations that go across an agency of 18,000 people and another 100,000 folks who engage in launch operations and the continued activities of the agency," O'Keefe said.
In the e-mails, engineers in Texas and Virginia fretted about the shuttle's safety during its final three days in orbit. One speculated whether officials were "just relegated to crossing their fingers" and another questioned why such dire issues had been raised so late.
"Why are we talking about this on the day before landing and not the day after launch?" wrote William C. Anderson, an employee for the United Space Alliance LLC, a NASA contractor, less than 24 hours before the shuttle broke apart Feb. 1 while returning to Earth.
NASA said those messages — including the few that were hauntingly prescient — were part of a "what-if" exercise by engineers convinced the shuttle would land safely despite possible damage from foam that struck insulating tiles on the spacecraft's left wing at liftoff.
"It was a surprise to us when the 'what-if' scenario played out," said Robert Doremus, head of the mechanical systems group in Mission Control. "We were not expecting that."
The engineers' e-mails also showed that the space agency was sufficiently concerned about possible damage to Columbia that it asked the Defense Department — then abruptly changed its mind — to take pictures of the shuttle in orbit more than one week before its breakup.
The request came six days into the mission, on Jan. 22, for the U.S. Strategic Command to take satellite images of suspected damage to the shuttle's left wing. For weeks until Wednesday, NASA has denied it ever made such a request.
The space agency withdrew its informal request one day later amid fears it might have "cried wolf" and endangered future such requests, according to one e-mail.
Deciding against the satellite request, a space official wrote reassuringly to the Defense Department that Columbia was "in excellent shape" and that insulating foam that struck the shuttle on its mid-January liftoff was "not considered to be a major problem."
Not everyone agreed.
Three days before the end of the doomed mission, one frustrated engineer, Robert Daugherty, asked, "Any more activity today on the tile damage or are people just relegated to crossing their fingers and hoping for the best?" The response: "I have not heard anything new."
After intense debate — occurring by phone and e-mails — the engineers, some supervisors and the head of the space agency's Langley research facility in Hampton, Va., decided against taking the matter to top NASA managers, including William F. Readdy, NASA's associate administrator for space flight.
"I think this is part of the process that NASA normally goes through when they do simulations between missions; they always are pretending things have gone wrong," reports CBS News Space Consultant Bill Harwood. "They say that this was simply a part of that and certainly nothing all that out of the ordinary.
"But you do have to wonder if management shouldn't have been involved in some of these discussions as this went on."
Jeffrey V. Kling, a flight controller at Johnson Space Center's mission control, foresaw what might happen to Columbia during its fiery descent: that superheated air could penetrate the wheel compartment and cause the wing to fail.
Kling wrote just 23 hours before the disaster that his engineering team's recommendation in such an event "is going to be to set up for a bailout (assuming the wing doesn't burn off before we can get the crew out)." The following day, Kling was among the first in mission control to report a sudden, unexplained loss of data from the shuttle's sensors in the left wing.
"This was just a mental exercise that we went through to 'what-if' the whole thing," Kling said.
The shuttle crew had individual parachutes, but the chutes wouldn't have done them any good at the speed and altitude they were flying when Columbia broke up.
The e-mails showed the debate was triggered by a telephone call Jan. 27 to Daugherty from Carlisle Campbell, a NASA engineer at Johnson Space Center, about how re-entry heat could damage the shuttle's tires.
Another e-mail, from R.K. "Kevin" McCluney, a shuttle mechanical engineer at the Johnson center, described the risks that could lead to "LOCV" — NASA shorthand for the loss of the crew and vehicle.
McCluney ultimately recommended to do nothing unless there was a "wholesale loss of data" from sensors in the left wing. Investigators reported such a wholesale loss of sensor readings in Columbia's left wing, but it occurred moments before the shuttle's breakup — too late to do anything.
Meanwhile, with space shuttle flights on hold because of the Columbia disaster, a Russian space capsule now docked at the international space station will be used to bring the space station crew back to Earth now that the U.S. shuttle fleet is grounded, O'Keefe said.
O'Keefe told the congressional committee that the 16 countries participating in the space station had agreed to use the docked Soyuz capsule to ferry the crew home. Two new residents, one American and one Russian will go up on a fresh Soyuz that will remain attached to the station for the next six months.
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.