A year ago next Sunday, America's space program suffered one of its worst tragedies when the space shuttle Columbia disintegrated over East Texas, killing all aboard and suspending the shuttle program. Following are excerpts from a book, Comm Check ... The Final Flight of Shuttle Columbia, about the tragedy, written by Michael Cabbage, space editor of the Orlando Sentinel, and veteran CBS News space reporter William Harwood. The excerpt weaves together transcripts and other evidence to describe what happened during the fatal re-entry of Columbia from space to Earth.
"Looks like a blast furnace."
-- Shuttle commander Rick Husband, midway through re-entry
Plunging back to Earth after a 16-day science mission, the shuttle Columbia streaked through orbital darkness at 5 miles per second, fast enough to fly from Chicago to New York in 2 1/2 minutes and to circle the entire planet in an hour and a half. For Columbia's seven-member crew, the only hint of the shuttle's enormous velocity was the smooth clockwork passage of entire continents far below.
Commander Rick Husband knew the slow-motion view was misleading, a trick of perspective and the lack of anything nearby to measure against the craft's swift passage. He knew the 117-ton shuttle actually was moving through space eight times faster than the bullet from an assault rifle.
And Husband knew that in the next 15 minutes, the shuttle would shed the bulk of that unimaginable speed over the southwestern United States, enduring 3,000-degree temperatures as atmospheric friction converted forward motion into a hellish blaze of thermal energy. It had taken nearly 4 million pounds of rocket fuel to boost Columbia and its crew into orbital velocity. Now the astronauts were about to slam on the brakes.
For Husband, a devout Christian who put God and family ahead of his work as an astronaut, flying this amazing machine home from space was a near-religious experience, one he couldn't wait to share with family and friends gathered at the Kennedy Space Center in Florida. He had served as pilot on a previous shuttle flight, but this was his first as commander, and in the world of shuttle operations, it's the commander who actually lands the spacecraft.
He relished the opportunity. But before blasting off on his second space flight as commander of Columbia, he videotaped 34 Bible lessons for his two kids, one each for the 17 days he would be away from home.
"The space shuttle is by far the most complex machine in the world," he had told his hometown church congregation three years earlier. "And inside that vehicle are seven astronauts, each one of which is more complex than this vehicle we went up in," he continued. "And God is an awesome God."
Looking over his cockpit instruments as he prepared Columbia for entry, the 45-year-old Air Force colonel chatted easily with his crewmates, coming across more as an older brother than as the skipper of a $3 billion spacecraft. But beneath the camaraderie was the steady hand of a commander at ease with leadership and life-or-death responsibility.
It was 8:44 a.m. on Feb. 1, 2003, and Columbia was descending through 400,000 feet northwest of Hawaii.
"OK, we're just past EI," Husband told his crewmates, marking when Columbia, flying wings level, its nose tilted up 40 degrees, finally fell into the discernible atmosphere.
He was referring to "entry interface," the moment the shuttle descended through an altitude of 76 miles. At that altitude -- 11 times higher than a typical passenger jet flies -- the atmosphere is still a vacuum in the everyday sense of the word. But enough atoms and molecules are present to begin having a noticeable effect on a vehicle plowing through them at 25 times the speed of sound.
Wearing bulky, bright orange pressure suits, Husband, rookie pilot William "Willie" McCool, flight engineer Kalpana Chawla (pronounced KULP-nah CHAV-lah), and Navy physician-astronaut Laurel Clark were strapped into their seats on Columbia's cramped flight deck, working through the final entries on a long checklist.
The shuttle's flight computers, each one taking in navigation data and plugging the numbers into long strings of equations, were doing the actual flying. Husband wouldn't take over manual control until the orbiter was on final approach, 50,000 feet above the Kennedy Space Center at Cape Canaveral, Fla.
Husband was in the front left seat, the command position aboard any aircraft, with McCool to his right on the other side of a switch-studded instrument console. Chawla, a native of India, was a veteran of one previous shuttle flight and an accomplished pilot. Something of a legend in her hometown of Karnal in the Indian State of Punjab, Chawla was a role model in a country where less than half the women were literate. She sat directly behind the central console, calling out and double-checking re-entry tasks. Clark was seated to Chawla's right, almost touching shoulders with the diminutive flight engineer.
Strapped into seats on the split-level crew cabin's lower deck were payload commander Michael Anderson, another shuttle veteran and one of only a handful of African-American astronauts at NASA, physician-astronaut David Brown, a former circus acrobat, jet pilot and amateur videographer, and fighter pilot Ilan Ramon, the first Israeli to fly in space.
Unlike the upper flight deck with its wrap-around airliner-type cockpit windows and large overhead view ports, the lower deck featured a single, small porthole in the shuttle's main hatch, almost out of view on the left side of the cabin. For Anderson, Brown and Ramon, there was nothing to see but rows of equipment lockers. At least they were plugged into the ship's intercom system, following along as the flight deck crew worked through the re-entry checklist.
They were listening in a half-hour earlier as Husband counted down to de-orbit ignition, when Columbia's flight computers fired up the shuttle's twin braking rockets as the spacecraft flew upside down and backwards 170 miles above the central Indian Ocean. The 2-minute 38-second rocket firing slowed the shuttle by just 176 mph. But that small decrease was just enough to lower the far side of Columbia's orbit deep into the atmosphere above Florida's east coast.
For the first half-hour of re-entry, Columbia and its crew simply fell through the black void of space on a precisely plotted course toward a runway on the other side of the planet. But now, finally back in the discernible atmosphere, things were about to get interesting.
For McCool, an accomplished Navy carrier pilot and father of three who brought a boyish enthusiasm to Columbia's flight deck, entry interface was a long-anticipated milestone. Veteran astronauts had told him to expect a spectacular light show. Right on cue, the inky blackness outside his cockpit windows began giving way to a faint salmon glow.
At first, the effect was so subtle he wasn't sure it was really there.
"That might be some plasma now," he observed, as if seeking confirmation from Husband.
"Think so already?" asked Clark, seated directly behind McCool and aiming a handheld video camera out the cockpit's overhead windows. (The videotape was later found in the shuttle's wreckage.) "That's some plasma," Husband finally confirmed.
"Copy, and there's some good stuff outside," Clark replied. "I'm filming overhead right now."
"It's kind of dull," McCool said a moment later, as if disappointed.
"Oh, it'll be obvious when the time comes," Husband reassured him.
McCool didn't have to wait long. During the next minute, the initial faint glow steadily brightened until there was no mistaking that the shuttle was embedded in a fireball.
"It's going pretty good now, Ilan," McCool reported to the three fliers on the lower deck. "It's really neat, just a bright orange-yellow out over the nose, all around the nose."
"Wait until you start seeing the swirl patterns out your left and right windows," Husband said.
"Looks like a blast furnace," Husband said dryly.
No need for concern
Even so, he and his crewmates were not worried. Focused, yes. Aware of the danger, yes -- as any well-trained astronauts would be when contemplating the energies involved in a shuttle launch or re-entry. But not worried. After all, there was no reason for concern. In the 111 previous space shuttle re-entries, there never had been a catastrophic "in-flight anomaly," as NASA refers to out-of-the-ordinary events. The only disaster in the history of the program, the Challenger explosion, had occurred during launch when one of its boosters had ruptured.
The Columbia astronauts already had survived the 8 1/2 -minute climb to orbit that most experts, with some reason, considered a far more dangerous phase of flight. A fully fueled space shuttle weighs 4.5 million pounds at liftoff, yet accelerates to 100 mph -- straight up -- in about 10 seconds. In the first minute, more than 2 million pounds of fuel are consumed by the ship's twin solid-fuel boosters and three hydrogen-fueled main engines as the spacecraft plows its way through the dense lower atmosphere. Seven and a half minutes later, the astronauts are in orbit, moving through space at more than 17,000 mph.
Compared with launch, getting home was a walk in the park. Or so it seemed to most, including many at NASA. The astronauts knew better, of course. All of the energy it took to boost Columbia to orbital speed was still there in the form of the craft's enormous velocity. To make it back to Earth, the shuttle would have to give up that energy in the form of heat from atmospheric friction.
"This is amazing. It's really getting, uh, fairly bright out there," McCool observed as the glow around the orbiter continued to intensify.
"Yeah, you definitely don't want to be outside now," quipped Husband.
"What, like we did before?" Clark said pointedly as her crewmates laughed.
"Good point," Husband replied.
Dropping like a rock
It was 8:47 a.m. and just three minutes had passed since entry interface. Approaching the coast of northern California, Columbia was dropping like a rock, its nose-up orientation designed to focus re-entry temperatures of up to 3,000 degrees on the heat-resistant reinforced carbon-carbon (RCC) panels making up the wings' leading edges and the orbiter's nose cap. Thousands of black heat-shield tiles making up the belly of the spacecraft would protect the underlying, vulnerable, aluminum skin from slightly lower, but still extreme, temperatures.
The spacecraft had not yet slowed much -- its velocity was still a blistering 24.7 times the speed of sound -- but aerodynamic pressure was steadily building across the underside of the shuttle. It was now up to a half-pound per square foot as the craft continued its descent through the thin upper atmosphere. In another minute, it would quadruple, and one minute after that, it would be 20 times greater. Temperatures on the nose and the wing's leading edges already were above the 1,200-degree melting point of aluminum.
The astronauts were putting on their gloves, pressurizing their spacesuits and conducting routine communications checks to make sure they could hear each other with their helmet visors down and locked. Clark, who planned to videotape the entire descent, was fiddling with her camera, taking occasional shots through the overhead windows as the plasma continued to build around the vehicle.
"Willie, I can see you in your mirror," Clark said playfully, looking over the pilot's shoulder at a small mirror attached with Velcro to the forward dashboard.
"Now I can see your camera!" McCool said to Clark, looking back in the mirror.
"OK," Husband said, his tone of voice gently telling his crewmates to cut out the horseplay.
"Stop playing," Chawla acknowledged with good humor.
'What in the world?'
Just before 8:50 a.m., still off the coast of California, Columbia's computers ordered small, right-side steering rockets to fire, moving the shuttle's nose to the right. These roll maneuvers were planned to bleed off velocity before reaching the landing site.
McCool was looking forward to getting a little flying time in the next few minutes. After receiving the go-ahead to fire Columbia's braking rockets to begin the trip home, Husband had notified Mission Control that McCool would be taking the stick briefly, just before touchdown, as the shuttle banked to line up on the runway. Not every commander gave his or her co-pilot a chance to actually fly the shuttle, but that was Husband's nature. McCool couldn't wait.
As Columbia streaked toward the California-Nevada border more than 2,000 miles away, mechanical systems officer Jeff Kling, monitoring telemetry from the shuttle's myriad systems at Mission Control in Houston, noticed something unusual. Downward-pointing arrows appeared beside readings from two sensors measuring hydraulic fluid temperatures in the shuttle's left wing.
"What in the world?" another mechanical systems engineer, seeing the same data in a different room, said to Kling.
"This is not funny," Kling replied. "On the left side."
"On the left side," the engineer agreed.
They both tried to find some common thread that might explain the readings. Then, a few seconds later, two more down arrows appeared. It was as if the wiring to the four sensors in question, in hydraulic lines leading to the wing's flaps, or elevons, had been cut. Kling notified Flight Director LeRoy Cain.
"FYI, I've just lost four separate temperature transducers on the left side of the vehicle, hydraulic return temperatures," Kling reported, speaking quickly. "Two of them on system 1 and one in each of systems 2 and 3."
"Four hyd return temps?" Cain calmly asked.
"To the left outboard and left inboard elevon."
"OK, is there anything common to them? ... I mean, you're telling me you lost them all at exactly the same time?"
"No, not exactly," Kling said. "They were within probably four or five seconds of each other."
"OK," Cain said, mulling over possible explanations. "Where are those, where is that instrumentation located?"
"All four of them are located in the aft part of the left wing, right in front of the elevons, elevon actuators," Kling replied. "And there is no commonality."
Cain pondered that for a moment.
Flashback to launch
"No commonality," he said after a long pause, his tone of voice indicating bafflement. Multiple sensor failures were rare, usually the result of problems with some common electrical system or component shared by the sensors in question. But these data "dropouts" could not immediately be traced to some single failure point.
Cain's thoughts flashed back to Columbia's launch. He recalled a briefcase-sized piece of foam insulation that broke away from Columbia's external fuel tank 81 seconds after liftoff and slammed into the underside of the left wing. A team of experts had studied the impact and dismissed it as not being a safety-of-flight issue. The Mission Management Team had unanimously accepted the results of the analysis.
An unsettling thought crossed Cain's mind. Was the loss of four left-wing temperature sensors related to the foam strike? It couldn't be, he thought. That had to be a coincidence.
"Tell me again which systems they're for?"
"That's all three hydraulic systems," Kling said. "It's ... two of them are to the left outboard elevon and two of them to the left inboard."
"OK, I got you," Cain said. It was 8:56 a.m. and Columbia was crossing the Utah-Arizona-New Mexico state lines. Aerodynamic pressure was up to 40 pounds per square foot as the shuttle continued its steep descent.
Focus on left wing
In the management viewing room above Mission Control, Linda Ham was also worried. About the left wing. About the foam strike earlier in the mission. In her pivotal role as chairwoman of the Mission Management Team, Ham had approved the analysis that concluded the foam strike was not a safety-of-flight issue. She turned to Ralph Roe, the shuttle's engineering director, a tall ex-football player who also had taken part in the deliberations.
"Ralph, it's the left wing."
"It's not that," he said.
Nothing else in the continuous stream of data from Columbia indicated any signs of trouble. In just three minutes, the shuttle would be out of the region of maximum aerodynamic heating. There was reason to hope that all was well.
Suddenly, Husband called down, his first query since Columbia had entered Earth's atmosphere 15 minutes earlier.
"And, uh, Hou[ston] ... ," he began. His transmission was cut off.
Such dropouts were not unusual during re-entry as the shuttle banked left and right, its big vertical tail fin occasionally blocking signals from reaching a NASA communications satellite stationed over the western Pacific.
A few seconds later, Kling saw more down arrows appear on his computer screen, this time signaling a loss of data from the shuttle's left main landing gear tires.
"We just lost tire pressure on the left outboard and left inboard, both tires," he told Cain, a half-minute after Husband's interrupted call. Astronaut Charles Hobaugh, the flight controller responsible for talking directly to the shuttle crew, heard Kling's report to Cain and promptly radioed Husband: "And Columbia, Houston, we see your tire pressure messages and we did not copy your last."
Seconds later, Husband made another attempt to contact Mission Control, replying to Hobaugh with "Roger, uh, buh..." He might have been saying "before" or "both," but again, the transmission was suddenly cut off and, along with it, the flow of data from the shuttle.
It was 8:59:32 a.m.
'This is not right'
As far as the public knew, everything was proceeding smoothly. Communications dropouts typically lasted several seconds, occasionally longer, but sooner or later communications always resumed. Even so, at the Kennedy midfield viewing site, Bill Readdy, NASA's associate administrator for space flight and the man ultimately responsible for shuttle operations, started paying attention.
Much of the crowd in Florida was oblivious to the drama unfolding in Mission Control. But a couple of reporters huddled around a television set inside the runway's public affairs building had noticed something peculiar.
The big map displayed in Mission Control and broadcast on NASA Television showed Columbia's progress as the ship sped across the continent toward Florida, the red triangle marking the shuttle's position. Inexplicably, that triangle had stopped moving over Central Texas.
Hobaugh radioed Husband to check whether the crew could hear communications from Houston.
"Columbia, Houston, comm check," Hobaugh called at 9:03 a.m. "Columbia, Houston, UHF comm check."
There was no reply.
"Columbia, Houston, UHF comm check," Hobaugh tried again. It was 9:04 a.m.
The shuttle now had been out of communication for nearly five minutes. At Kennedy's shuttle landing strip, a small flurry of activity had begun in the VIP area. Clusters of people had grouped together. The laughter and smiles of just 10 minutes earlier had all but disappeared, erased by anxious looks of concern.
Controllers were expecting tracking radars near Kennedy to lock onto Columbia at any moment as the shuttle approached Florida. By now, they knew something was very wrong. Columbia had been out of contact longer than anyone had expected.
"When were you expecting [radar] tracking?" Cain asked the flight dynamics officer at 9:05 a.m.
"One minute ago."
At the shuttle runway, cell phones starting ringing. Soon, it appeared half the people in the crowd had phones pressed against their ears. Sean O'Keefe, NASA's administrator, heard Readdy say, "This is not right, something is not right on this." O'Keefe was stunned. Readdy, the veteran shuttle commander and former fighter pilot, was visibly trembling, his face ashen.
Unaware of the dread
"It was just one of those hit-you-with-a-mackerel kind of moments," O'Keefe said. "You know, 'Good God almighty.' You see someone like him sitting there doing that, and he knows the gravity of it better than anybody. It was enough to make you just start shaking right down to the edge."
Kennedy shuttle manager Mike Wetmore was overwhelmed. He turned to look at the astronauts' families, the kids still running around in front of the bleachers, unaware of the sense of dread settling over the managers. He was paralyzed by the sight.
"The families were celebrating and happy and I just ... I couldn't move. They had no idea," Wetmore said. "I am a dad, I am a dad with two small kids and I am looking over there at these little kids running around, playing and laughing. I just remember a couple of small kids chasing each other back and forth. I was just standing there frozen."
"Columbia, Houston, UHF comm check," Hobaugh radioed again.
There was no reply.
Copyright c2004 by Michael Cabbage and William Harwood. From the forthcoming book "Comm Check" by Michael Cabbage and William Harwood to be published by Free Press, a division of Simon & Schuster, Inc., N.Y. Printed by permission.
Columbia Accident Investigation
Report of Aug. 26, 2003
* The physical cause of the loss of Columbia and its crew was a breach in the thermal protection system on the leading edge of the left wing.
The breach was initiated by a piece of insulating foam that separated from the left bipod ramp of the external tank and struck the wing in the vicinity of the lower half of reinforced carbon-carbon Panel 8 at 81.9 seconds after launch.
During re-entry, this breach in the thermal protection system allowed superheated air to penetrate the leading-edge insulation and progressively melt the aluminum structure of the left wing, resulting in a weakening of the structure until increasing aerodynamic forces caused loss of control, failure of the wing, and breakup of the orbiter.
* In the board's view, NASA's organizational culture and structure had as much to do with this accident as the external tank foam. . . . The shuttle program's safety culture is straining to hold together the vestiges of a once-robust systems safety program.
* The silence of program-level safety processes undermined oversight; when they did not speak up, safety personnel could not fulfill their stated mission to provide "checks and balances."
A pattern of acceptance prevailed throughout the organization that tolerated foam problems without sufficient engineering justification for doing so.
* President John Kennedy's 1961 charge to send Americans to the Moon and return them safely to Earth "before this decade is out" linked NASA's efforts to core Cold War national interests.
Since the 1970s, NASA has not been charged with carrying out a similar high-priority mission that would justify the expenditure of resources on a scale equivalent to those allocated for Project Apollo.
The result is the agency has found it necessary to gain the support of diverse constituencies. NASA has had to participate in the give and take of the normal political process in order to obtain the resources needed to carry out its programs. NASA has usually failed to receive budgetary support consistent with its ambitions.
The result . . . is an organization straining to do too much with too little.