Quotes of the Day

The last song the lost crew of the space shuttle Columbia ever heard was Scotland the Brave by the 51st Highland Brigade. That was the wake-up song beamed up by NASA on the morning the ship was supposed to return to earth. The day before it had been Shalom Lach Eretz Nehederet, for Israeli astronaut Ilan Ramon. Thursday morning it had been John Lennon's Imagine. Scotland the Brave was for mission specialist Laurel Clark, Scottish by extraction.

"Good morning," Mission Control called up to the ship.

"Good morning, Houston," Clark answered. "We're getting ready for our big day up here ... I'm really excited to come back home. Hearing that song reminds me of all the different places down on Earth and all the friends and family that I have all over the world. "

She had reason to be excited, particularly since that business of coming home should have been relatively routine—at least by the high-wire standards of space travel. After shimmying out of their sleep restraints, the crew would stow gear and belt themselves into their seats—a process that would take a good six hours. With Columbia turned rump forward, the commander would then fire the main maneuvering engines, slowing the spacecraft and easing it toward the upper wisps of the atmosphere. Once he turned the ship around, he would surf the currents of the steadily thickening air, fishtailing this way and that until, just an hour or so after the deorbit engines were lit, Columbia's tires would make their smoking contact with the Cape Canaveral runway and the shuttle would come to a rolling stop.

That's the way it ought to have happened, at least—and that's the way it did happen on 111 earlier shuttle flights, 27 of them by the venerable Columbia. But only 15 minutes from its planned touchdown, more than 200,000 ft. (61,000 m) over Texas, the 22-year-old ship suddenly and fatally deconstructed itself, taking the lives of its seven crew members with it.

"A space-shuttle contingency has been declared," the voice of Mission Control intoned in the arid argot of the space agency. It was an echo of the understated announcement 17 years ago, when the shuttle Challenger consumed itself in an awful fireball, and the stunned NASA narrator was left to declare, "Obviously a major malfunction." Then, as now, the question is the same: Why?

A full inquest into the death of the shuttle Columbia—the second of the star-crossed fleet of five to be lost in flight—will take months if not years. Investigators will be looking at everything from a loss of insulating tiles to an explosion in the fuel tanks to a structural failure in the bones of the ship itself, as Columbia juked and torqued its way through the atmosphere. In a flying machine with more than 2.5 million parts, even a 99.9% reliability level would still leave 2,500 things to go wrong.

However long the investigation takes, it will start with an examination of the last 45 min. of Columbia's life. Commander Rick Husband fired his deorbit engines at 8:15 a.m. E.T. when the ship was high over the Indian Ocean. Half an hour—and half a world—later, it hit the edges of the atmosphere just north of Hawaii at an altitude of about 400,000 ft. (122,000 m). Shortly after, a faint pink glow began to surround the ship, as atmospheric friction caused temperatures to rise to between 750 degrees F and 3,000 degrees F across various parts of the spacecraft's exposed underbelly.

The astronauts, busy monitoring their deceleration, temperature, hydraulics and more, didn't have much time to watch the light show play out, and by the time the glow brightened from faint pink to bright pink to plasma white, the ship had arced around the planet into thick air and daylight. "It all happens so smoothly ... you hardly notice it," says retired astronaut Henry Hartsfield Jr., who piloted Columbia in the early 1980s.

On the ground, things were smooth too. At Cape Canaveral the conditions were perfect for landing, with temperatures in the low 70s and a light breeze blowing, well within NASA's wind limits. The families of some of the seven crew members had already been shown to the runway, assembling for their close-up view of the touchdown. The pit crew that takes custody of the shuttle and shepherds it back into its hangar was standing by to claim Columbia as soon as the crowd cleared. In Mission Control in Houston things were similarly routine. "Many of us came in today marveling at the fact that one of the most difficult things we deal with is weather and we didn't have any weather issues anywhere in the world," says chief flight director Milt Heflin.

The weather would soon seem irrelevant. At 8:53 a.m., when the ship was crossing over San Francisco, a data point flickered on monitors at Mission Control indicating that the flow of information recording the temperature of the hydraulic systems in Columbia's left wing had suddenly ceased. At 8:56, when the ship was somewhere over Utah, the temperature in the landing gear and brake lining—again on the left side—registered high. Two minutes later, three temperature sensors embedded in the skin on the left flank of the ship quit transmitting. A minute later, temperature sensors in the left tires winked out too. All these data hiccups were reported by the mission controllers to the flight director. Finally, when the spacecraft was about 207,000 ft. (63,000 m) above Texas, Charlie Hobaugh, the spacecraft communicator, alerted the crew.

"Columbia, Houston," he said. "We see your tire-pressure message." "Roger," Husband responded. "Uh ..." All at once, communications were cut off as if by a knife, and with them went every other scrap of data coming down from the ship.

"Columbia, Houston," Hobaugh said. "Com check."

Static crackled back. "Columbia, Houston. UHF com check," Hobaugh said, as Mission Control switched channels.

Still no response.

"Columbia, Houston," Hobaugh repeated several more times, but still there was nothing. Mission controllers—at least the veterans—did not expect there would be.

"We lost all vehicle data," says Heflin. "That's when we began to know that we had a bad day."

Outside Mission Control, in the hot path the flaming Columbia cut through the sky, no one needed to see computer data to know the day had taken a bad turn. In Nacogdoches, Texas, 17-year-old Heath Drewery was in bed when he was jolted by what sounded like an explosion outside his house. "I heard this big rumble and thought a train had derailed," he says. He and his brother piled into their truck and drove into town, where the street was littered with debris. "There were pieces all over the place. It looked like it was charcoal." In San Augustine, things got more grisly still, when body parts fell from the sky.

With reports coming back of a debris field that stretched from eastern Texas to Louisiana, NASA put out the somewhat disingenuous word that fumes from the fragments could be dangerous and that people who found them should leave them where they lay and alert the authorities—as if any toxic fuel could have survived the heat of re-entry. The more probable reason for the space agency's alerts was that tampering with the remains would make a proper investigation of the disaster that much harder. Worse, within hours pieces of debris purported to be from the lost space plane were already being hawked on eBay. Nobody wanted to see more of that.

At Camp David. President Bush was in his cabin when chief of staff Andrew Card learned of the accident while channel-surfing. He phoned the President, who decided to return to the White House by motorcade. A grim Bush scheduled a conference call with the families for 12:45 and at 12:30 was standing at his desk in the Oval Office scanning biographies of the crew members to see which ones had spouses and children.

"Tough day, tough day," he muttered. After placing the call, he left the office briefly to compose himself.

"He was emotional," said a speechwriter who was there. "He was misty eyed."

As NASA starts trying to pinpoint the cause of all this horror, investigators will have a lot of places to turn. The mission began with at least one anomaly when, at the moment of launch, a piece of foam broke from the insulation on the giant external fuel tank and struck the left wing of the ship. "We spent a goodly amount of time reviewing the film (of the launch) and analyzing what that might do," says shuttle program manager Ron Dittemore. "From our experience it was determined that the event did not represent a safety concern."

But that was before the hinky data started coming down from that same left side of the ship in the final seconds of the flight. Now the film that already got a once-over is going to be looked at a lot more closely. "We can't discount that those (events) may be connected," Dittemore admits, then hastens to add, "but a lot of things look like they're going to be the smoking gun in this business and turn out not to be."

If the falling foam did damage the ship, the most disturbing possibility is that it chipped or broke one or more of Columbia's heat-absorbing tiles. The spacecraft is protected from the hellish heat of re-entry by thermal blankets and about 24,000 black and white ceramic tiles. The jigsaw-puzzle pieces have given the space agency fits since the very first flight of the very first shuttle—Columbia in April 1981. Handfuls of them often flaked away during lift-off, leaving NASA with nothing to do but wait out the flight and hope that the skin had not been denuded in a critically hot spot. In a worst-case scenario, just a few missing tiles in even a relatively low-temperature area could lead to a fatal chain reaction, with possibly hundreds of them peeling away. "Losing a single tile can do you in," says Stanford University's Elisabeth Pate-Cornell, an engineer and risk-management specialist who once led a NASA study about all the ways shuttle tiles could fail. "Once you have lost the first tile, the adjacent ones become much more vulnerable." Since nothing this catastrophic ever happened in any of the prior shuttle flights, NASA grew increasingly—and justifiably—confident that the lightweight and durable shielding was the best of an admittedly imperfect set of options. Now there is reason to doubt. "Obviously, the loss of tiles has to be looked at and put to bed," says George Gleghorn, a former chief engineer for TRW's space group and, for six years, a member of a NASA safety-advisory panel. Others are asking why, if a piece of foam was known to have hit the ship, an astronaut wasn't sent outside during the course of the 16-day mission to determine whether any damage had been done.

Dittemore explains that this crew was not trained for that kind of extensive space walk, and even if they were and they found some damage, they could have done nothing about it anyway. "We had no capability to go over the side or under the spacecraft and look for an area of distress and repair a tile," he says.

That didn't stop people from wondering whether a space walk still might have been wise, since if the crew could somehow have determined that the tiles were compromised, they might at least have hightailed it to the International Space Station—which the shuttles routinely visit anyway—and awaited a lift home aboard another shuttle or a Russian vehicle. But that possibility was foreclosed, since crews must rigorously train for a space-station docking and must carry aboard an adapter collar to make the linkup possible. Neither of those conditions was met on Columbia.

If the tiles weren't responsible, the sheer turbulence of re-entry might have been. It's not for nothing that the first commander of a shuttle flight was Gemini and Apollo veteran John Young, widely respected as an iceman at the stick. If you're going to fly so tricky a ship, you have to be. "When you re-enter, you're moving at 25 times the speed of sound," says former astronaut Dr. Norm Thagard. Hitting the atmosphere at that velocity is "not unlike slamming into a brick wall, if you're not at the correct attitude."

The S-turns the pilots make are intended to bleed off speed in order to ease the shuttle down to Earth, but they are a lot more complicated than simply slaloming down a ski slope. The spacecraft's engines are shut off for good once it leaves orbit, meaning its descent is powerless. Flying a brick with wings, as the engineers have often called the ship, has a very fine margin of error. Lose your purchase on the air and go into a spin, and there's almost no way to pull out of it. "The attitude needs to be very, very precise," says Thagard. "You can pick up heat so fast you get a breakup."

Realistic as that scenario might seem, there was no sign of any such crisis in the final seconds of Columbia's flight, and unlike a tile failure, which could well go undetected until the very moment it claimed a ship, a piloting emergency would at least leave the commander time to sound an alert. Rick Husband made no distress call. In the weeks and months to come, other, less likely scenarios will be examined too: a meteor or other piece of space debris could have struck the spacecraft, a growing risk given the decades of accumulated orbital junk that clutters the near-Earth environment. In this case, that's not likely, since the shuttle was already well into the atmosphere when it disintegrated. Age or metal fatigue could have been responsible as well. All four orbiters were temporarily grounded last June when cracks were found in their liquid-hydrogen fuel lines, damage that may have been caused by vibration, temperature changes or other stressors accumulated over repeated flights. Columbia, as the granddad of all the ships, could have been the brittlest of the fleet. But NASA, for all its alleged shortcomings, leaves little to chance in the regular physicals it gives its shuttles, and the fact that these tiny cracks were found in fuel lines makes it all the less likely that larger, lethal cracks could have gone unnoticed. A fuel explosion is also a possibility but again a remote one. When the ship re-enters the atmosphere, there's not much juice left in the main maneuvering rockets or in the spritzy little thrusters arrayed around the spacecraft.

In the wake of Sept. 11, it's not surprising that many Americans immediately wondered whether terrorism could have been responsible. A shoulder-launched missile could, in theory, bring down an aircraft, but Columbia was well beyond a missile's altitude limit at the time the ship disintegrated. The idea that an explosive could have been smuggled aboard got no serious attention. It would be almost impossible for even the most committed terrorist to breach NASA security, all the more so with the heightened protection thrown up around a ship carrying an Israeli astronaut celebrated for having participated in the attack on Iraq's nuclear reactor in 1981.

For now, Washington will do what Washington too often does in a time of crisis: point fingers. Florida Senator Bill Nelson—famous for having sweet-talked his way onto the same shuttle Columbia when he was a Congressman, landing just 10 days before the Challenger disaster sobered the space community to the risks of such joyrides—has been warning colleagues that budget cutbacks threatened to compromise spacecraft safety. "I have been perhaps the sharpest critic in Congress about the slowing down of safety upgrades," he says.

Representative Dave Weldon, Republican from Florida and co-chair of the House Aerospace Caucus, foresees a catfight in Congress over any new space expenditures, especially in an era of again ballooning deficits. "The people who opposed space-flight funding are going to come forward again and voice concerns that we should spend the money on something else," he says. "But we are a nation of explorers, and we'll continue to explore the unknown."

Whether we will is impossible to know. The space station has long been a fiscal black hole, and with the eventual cost of the massive outpost projected to top $100 billion, NASA is not likely to abandon it without a mighty fight. The three crewmen currently on board—two Americans and a Russian—have a Soyuz re-entry vehicle aboard, and both the U.S. and Russia have the wherewithal to go fetch them if that should fail. But once they're gone, will anyone be back? The space station can't operate without the shuttle to service it, and with 40% of the tiny shuttle fleet—not to mention 14 lives—now claimed by explosions, it may become indefensible to fly the ship.

And yet the U.S. is stubborn when it comes to space. Only 21 months after the Apollo 1 fire took the lives of three astronauts in 1967, NASA was flying again. The recovery time for the Challenger disaster was longer but still less than three years. Americans have suffered a lot of loss and hung a lot of crape since September of 2001, and war drums beating, they are likely to hang still more. Nations, like people, can sometimes grow too tired to be brave. At the same time, doing one thing—and doing it exceedingly well—can be a remarkable tonic. In the bright nights of the Apollo flights, Americans did that one great thing. With the right will, they could do it again.

—Reported by Deborah Fowler/Houston; Greg Fulton/Atlanta; Cathy Booth-Thomas/Nacogdoches; Jerry Hannifin/ Cape Canaveral; John F. Dickerson, Sally Donnelly, Eric Roston, Elaine Shannon, Mark Thompson, Karen Tumulty and Doug Waller/Washington; and David Bjerklie and Alice Park/New York; with other bureaus

• Jeffrey Kluger