By the Milk River on the Fort Belknap Indian Reservation in
, Chauncy Birdtail woke up the day Columbia crashed the way he did most mornings — worried.
As a part-time firefighter, Birdtail, 26, spent too many weeks in smoldering mountain wastes far from his wife and three children.
Like many members of the Gros Ventre and Assiniboine tribes, he struggled for steady work. To make ends meet, he had a part-time job filling in for an elementary school janitor.
Now his wife was pregnant again. He also faced an overdue drunk-driving fine and had no idea how to earn the $900 to pay it off.
The space shuttle was the furthest thing from his mind.
Then the U.S. Forest Service put out a call for firefighters to join the search for debris.
Birdtail hesitated. If he stayed behind, there was still a chance he could make his janitor's job into something full time.
On the other hand, he needed that $900. The Forest Service was paying $11.64 an hour. There was no way he could earn that kind of money at home.
Birdtail said goodbye to his family one more time and, like thousands of others, joined the search for Columbia.
Investigators were anxious to find recorders, cameras and computers, anything with a memory, especially the craft's most precious electronic repository — its flight data recorder.
, the National Guard, the
at Barksdale Air Force Base near Shreveport, La., within hours of the accident, then fanned into counties in East
Searchers slashed through lowland thickets of 2-inch thorns, hoping luck would lead them to anything that could further the investigation.
One morning, NASA recovery operations chief David Whittle looked up from his desk at Barksdale and realized that 5,600 people were under his authority for the day, searching for wreckage in an area almost the size of
To quicken the recovery of debris, Whittle pressed into service two satellites, a U-2 surveillance aircraft, 37 helicopters and seven other airplanes. He tried to hire a blimp. He quickly learned that the debris was too small to be seen from the air, the vegetation too thick.
People had to search on foot.
Chauncy Birdtail and other recruits walked in rows 10 feet apart. They shook debris from trees, tore it free of thorn thickets. They dug it up from golf courses, swept it from schoolyards and pried it off the windshields of cars.
At the murky bottom of Toledo Bend Lake, along the border between Texas and Louisiana, 60 divers felt among the submerged tree stumps. They made more than 3,300 dives. They found no debris.
When searchers came across a fragment, they marked its position with a flag.
"You got to holler out when you find what you think is a shuttle piece," Birdtail said.
They noted the location of each possible specimen of human flesh with a pink ribbon.
Every new find was logged with its GPS coordinates. Searchers tested all pieces for toxic chemicals and fumes, then sealed them in plastic sandwich bags at the rate of 1,000 pieces a day.
In three weeks of searching, Birdtail had found a shuttle circuit board, a gasket seal, a scrap of insulation and a piece of the fuselage the size of a storm door.
After a 12-hour day in the field, he and his crew would return to their camp tents. In the evening, NASA workers showed them videos about the space shuttle or handed out bumper stickers and souvenir pins.
When days passed without an additional discovery, the contract firefighter got depressed.
"You push and push. I was really in the downs because I didn't have no finds," Birdtail said. "The copperheads would chase you. You see a water moccasin every day. I was just wanting to go home."
One evening, an astronaut came by to talk with the firefighters about the life in the sky.
Birdtail had a question for the first astronaut he had ever seen: How much do you get paid?
The astronaut instead pointed out a moving spark in the sky.
"I will show you Alpha," she said. It was the International Space Station passing overhead.
"It looked like a big, bright old star," Birdtail said, "but it was moving so fast, not like a comet or nothing, but at its own little speed. That was cool."
The men and women in the blue flight suits seemed to materialize from the debris itself.
Whittle had not expected NASA astronauts themselves to commandeer the search for human remains.
"I'm not sure who gave them authority to do that," Whittle said. "It wasn't according to plan . The crew like to take care of their own."
When a crucial piece of wreckage was discovered, an astronaut frequently would ferry it personally to a laboratory for analysis, as if no one else could be trusted with its care.
In time, every major technical meeting or public hearing had one or more astronauts in attendance. They seemed to offer themselves as living reminders of what had been lost and, perhaps, in atonement for survivor's guilt.
As indentured servants of spaceflight, NASA's astronauts were both powerful and powerless.
The lives at stake were theirs, and they risked them willingly. But if they raised too many questions, they risked losing their only chance to fly in space, or possibly killing the shuttle program itself.
Adding to the pressure, the space agency routinely hired and trained far more astronauts than could ever be accommodated on scheduled shuttle flights, the agency's inspector general reported earlier this year.
Consequently, astronauts now waited years longer than their predecessors for a shuttle flight. In the interim, they trained, handled engineering jobs and performed public relations functions.
In public, they were careful to display all the scripted spontaneity of
tour guides. About five a year resigned.
During the recovery operation, the astronauts took charge of everything the Columbia crew had touched, worn or used during the mission, including the twisted wreckage of the compartment that had sheltered them.
They sequestered the crew module wreckage in a locked corner of the reconstruction hangar at the
Most accident investigators were refused access. Computer files containing information about the module were encrypted. Photographs of the wreckage were locked away or kept on secure computers.
In all, searchers recovered about half of the crew module, according to the agency's internal reports.
It had been ripped apart by aerodynamic stress over about a half a minute — "tormented," one investigator said.
NASA launched an internal investigation of the crew wreckage and, for a time, kept it secret from everyone else involved in the reconstruction effort and the independent accident investigation.
No one would say whether the special handling of crew-related debris was driven by a sense of delicacy or shame.
Lacking comprehensive data from Columbia's onboard electronics, NASA accident investigators in February and early March had to rely on engineering intuition and technical analysis — informed guesswork.
Investigators were intrigued by a blurred image of the shuttle taken by two off-duty Air Force officers at the Starfire Optical Range in Albuquerque.
A volunteer — Julian Christou, a research specialist at the Center for Adaptive Optics at
— sharpened the picture through days of intensive computerized image enhancement, using techniques developed to clarify images of distant galaxies.
Even with his best efforts, the image of Columbia remained a smudge, but it revealed signs of an unusual disturbance around the leading edge of the left wing. It could have been caused by a crack, a dent or a tear in its skin.
Engineers at NASA's Langley Research Center looked at the data and wondered how that could match the only clues they had to work with: Columbia's last seconds of telemetry signals transmitted to Mission Control in Houston.
The signals showed four failing sensors in the wheel well and abnormal temperature readings from two sensors along the back of the left fuselage.
What damage near the front of the craft would cause a flow pattern that would affect temperatures at the rear?
"Whatever that damage was, it was moving the flow field around," said aerodynamics expert Bill Scallion, who has been with NASA since it was founded. "You get a tremendous amount of heating when you come in at 25,000 feet a second."
They tested their ideas with scale models of the shuttle in Langley's hypersonic wind tunnels among the groves of pin oak and pine outside Hampton, Va.
A team led by Thomas Horvath, an expert in aero-heating and hypersonic flight, used a ceramic model constructed for the Challenger investigation 17 years before.
The model was coated with a temperature-sensitive phosphor that glowed in different hues when heated. By tracing the shifting bands of color, they could map the heat enveloping the spacecraft.
They quickly made 70 such models.
To simulate a damaged tile, they cut out a tiny piece of tape and, using tweezers and a magnifying glass, fastened it to the model wing.
They put the tape in a different spot along the leading edge of the left wing on each model.
To imitate the effect of a damaged wheel well, they also poked a tiny dimple in the wing.
For two weeks, they tested their 70 creations at up to 18 times the speed of sound, using infrared cameras to reveal the flowing currents of heat.
They discovered that by positioning the tape near the middle of the wing's front edge, they could divert the thermal currents across the fuselage in a way that mimicked the sensor readings.
The accident had revealed a secret.
Homesick and scared, Chauncy Birdtail was running from a water moccasin when he saw a black box 20 feet away, cushioned in the damp carpet of pine needles.
He caught his breath.
"I thought it might be a microwave or a piece of a refrigerator," Birdtail recalled, "but it was the wrong color. I was so excited it brought me out of the snake shivers."
He scrambled toward it.
It was about an hour after lunch, about seven miles from Hemphill, Texas, 46 days after the accident.
Weighed down by search gear, Birdtail found it hard to move quickly. He had on a hard hat, goggles, a red backpack, a yellow Nomex shirt and green Nomex pants layered over by chain-saw chaps designed to blunt the briars.
Birdtail had seen nothing like this before. He was afraid to touch it.
The 58-pound black case was about the size of two videocassette recorders. Its top had cracked. He could see circuit boards and loops of magnetic tape.
His crew mates saw it and started shouting.
When the NASA supervisor showed up and located its serial number, he immediately radioed headquarters at Barksdale.
Birdtail had found the flight data recorder — the piece of wreckage at the top of NASA's search list.
The 22-year-old instrument, known officially as the Orbiter Experiment recorder, held all the information from the shuttle's sensors, readings on the ship's temperatures, pressures and other data during ascent and reentry.
All of that data spooled onto 9,200 feet of 1-inch tape on two reels the size of medium pizzas.
The recorder had been housed under a crew seat, its data to be downloaded only after landing.
"Our jaws dropped when we saw it," said John Hunt, a senior avionics expert at the United Space Alliance, which runs shuttle operations for NASA.
Inside the case, the tape had unwound in a tangle around the capstans and twisted against the recording heads. The impact had nicked and pinched it into a hundred folds, then stretched it into a fragile thread.
All of it was waterlogged.
An astronaut flew the box to Houston for inspection and then to
for cleaning and repair.
It was the most direct memory of the shuttle's last flight that investigators would find.
"There it was," Birdtail said, "some answers, anyway, for the astronauts what happened to them while they was riding home."