Some tiles found early in the recovery period exhibited orange or brown streaks that appeared to be gouged into the tile surface. People speculated almost immediately about similarly colored insulating foam coming off the external tank and gouging the tiles. Or, perhaps, it was evidence of something else impacting Columbia during reentry. Analysis of the streaks in the reconstruction hangar instead showed that they were melted Inconel from the leading edge attachment fittings on the left wing. This was material from inside Columbia that had blown out through a hole in the wing and had been deposited onto and melted into the surface of the tiles.16
Another scenario that we needed to disprove was the potential involvement of terrorists. NASA management and the Department of Homeland Security considered this only a very remote possibility, but it had to be checked out. I did not want my team to be worried about possible terrorism, so I brought in the FBI undercover. The FBI special agents appeared just to be regular researchers looking at the materials. They swabbed various pieces and found no evidence of explosive residue anywhere on the vehicle.
I never told the team about their visit.
—
The Spacehab double module carried in Columbia’s cargo bay almost completely disintegrated during the accident. Spacehab would normally never be exposed to the heat of reentry, so it was relatively unshielded except for thermal blankets. Even though the shuttle’s cargo bay doors protected it during the initial phases of reentry, the module was exposed to the full fury of heat and aerodynamic forces when Columbia’s main structure broke apart. As with the interior of the shuttle’s payload bay, much of the module’s aluminum structure and its insulation blankets were melted or consumed in the heat and friction of reentry. The only major parts of Spacehab’s structure that survived the accident were two long Inconel rods—which were found almost completely intact—and pieces of the dense bulkheads of the module.17
Many of the science experiments were destroyed outright during Columbia’s disintegration and reentry, and others were badly damaged. Those that survived were mostly the ones that the crew removed from Spacehab and stowed in the orbiter’s crew module lockers prior to reentry. Some searchers had found canisters or bits and pieces of experiments in the field. Pat Adkins, for example, found a bag of thick, creamy material with a plunger mechanism attached to the bag, which had been part of the “OSTEO” medical experiment to study bone cell growth. Electronic data for some experiments had been transmitted back to Earth during the mission, and a few data tapes partially survived the breakup.
One experiment caused a rare celebration when our workers examined it in the reconstruction hangar. Searchers found a thermos bottle-sized container from an experiment involving a colony of nematodes—small roundworms. The container had been inside one of the lockers in the crew module, so it was relatively well protected until the locker hit the ground. We were amazed to see living nematodes inside the container when it was opened in the reconstruction hangar. Nematodes have a short life span. Because this finding was several weeks after the accident, these were likely the descendants of the original animals in the experiment. Nonetheless, there was joy in the hangar at finding something alive—passengers of Columbia who survived the accident. “You look for the glimmer of hope where you can find it,” said Spacehab’s Marty McLellan.
A thorny legal issue arose regarding if and how material from scientific payloads in the orbiter should be returned to the researchers. Payloads and experiments on a shuttle mission technically belonged to the scientists—the principal investigators who designed and funded the experiments. However, NASA impounded all of the more than 2,200 pieces of recovered debris from Columbia’s experiments. NASA’s primary concern was to prevent anyone from selling the recovered debris as memorabilia to recoup their lost investment in the experiment. NASA established a process to allow the payload customers to petition for access to the experiments to recover scientific data. Both NASA and the CAIB had to approve the request. Most of the science recovery operations took place at the reconstruction hangar.18 The materials were then returned back to NASA custody.
All told, nine of the eighty experiments carried by Columbia were found inside metal boxes. Scientists who opened the containers believed that at least five of those experiments would yield usable data.19
—
Initially, the reconstruction team planned to lay out the pieces of wing tile on the grid on the hangar floor. Weeks into the process, engineers realized that having a few tiles laid out on the floor, still inside their collection bags, was not going to provide the big picture of how the left wing failed.
Each tile on Columbia was of a unique size and shape. We had all that information in our databases before the accident. Engineers tried using a modified version of KSC’s EMAP software application—designed to track the status of waterproofing the shuttle’s tiles in the Orbiter Processing Facility—to construct a virtual three-dimensional model of the recovered tiles and where they came from on the vehicle. While it showed which tiles had been recovered and which had not, it was not useful for seeing patterns in how the recovered tiles were damaged. We needed to use the tiles themselves to show us what happened.
In late March, we constructed a “tile table”—a platform with a full-size dimensional drawing of the 2,800 unique tiles on the left wing. As each piece of left wing tile came back, engineers identified it—sometimes based on a few millimeters of thickness—and placed it in the appropriate location on the tile table.
The tiles laid out on the table told a compelling story of the left wing’s disintegration. The carrier panel tiles, which were the closeout between the panels on the leading edge of the wing and the tiles covering the rest of the wing, clearly showed where the wing breach occurred. The carrier panel tiles behind the inboard leading edge panels 1 through 8 appeared relatively similar. The tiles behind panel 9, though, showed evidence of high heating. Their surfaces were slumped, and their undersides were coated with metallic deposits from interior portions of the wing.
From the burn patterns on the other tiles, we saw that hot plasma had entered the wing at high velocity—thousands of miles per hour—and pressurized the wing cavity. The pressure created vents, which blew the superheated plasma and molten metal out of the upper and lower surfaces of the wing. The materials blowing out through the lower vent formed an obvious burn pattern along the underside of the wing.
As the plasma stream cut through the leading edge spar, it heated the wing and caused the adhesive that held the tiles onto the wing surface to fail. Those tiles peeled off the wing. They were designed to take heat from their outside surfaces, not from the side where they were glued onto corresponding felt pads covering the ship’s wings. The degraded glue on the underside of those tiles clearly demonstrated that the wing was baking from the inside out.20
The heavily damaged tiles on the left OMS pod (at the left rear of the shuttle) and the left side of the vertical stabilizer also provided clear evidence that the insides of the left wing were melting. The airflow around the vehicle during reentry put the OMS pod and tail directly downstream of the wing. As the interior components of the left wing melted and burned, those materials were deposited on and heavily pitted the left OMS pod and left side of the tail. The right side of the tail and the right OMS pod exhibited none of that kind of damage. The right wing had therefore not melted prior to the orbiter’s breakup.
Plotting the tile recovery locations on a map also supported the theory about the location of the breach in the wing. The tiles found farthest west in the debris field all came from the left wing, in the areas behind leading edge panels 8 and 9. Many of these tiles had brown streaks on them—Inconel metal from the melted leading edge attachment fittings.21
We also needed to find out what happened to the leading edge of Columbia’s left wing. Many pieces of the reinforced carbon-carbon (RCC) leading edge of the shuttle’s wings came back from the field, in sizes ranging from larger than one square foot to smaller than a thum
bnail. Boeing’s Mike Gordon and NASA structures engineer Lyle Davis spent long hours using micrometers to study the thickness of each tiny piece. They determined which wing and which RCC panel they came from and how they fit together. It was painstaking work. Eventually, the leading edges of both wings began to take shape.
Since the leading edge panels are U-shaped in cross section and up to several feet long, it was difficult to fit them together meaningfully on a two-dimensional grid. First, the team tried tacking the pieces to Styrofoam shaped like the wing’s leading edge. This proved unsatisfactory, because the backsides of the RCC panels were not visible. It was impossible to examine the panels in relation to the pieces of support structure that were behind them on the shuttle’s wing. In April, KSC’s shops fashioned three-dimensional frames made out of clear polycarbonate to hold the pieces of RCC and their supporting attachment fittings in their correct orientation. These frames enabled investigators to look at the reconstructed leading edge components from all sides.
As with the tile tables, the RCC panels told a compelling visual story about the accident. Panels 1 through 7, on the inboard side of the wing, were fractured and broken from forces after the shuttle disintegrated. Globs of aluminum and other metals were spattered along their inner surfaces. The metallic attachment fittings that held the RCC to the wing were still partially intact.
At panels 8 and 9, no metallic fittings were found. The support structure here was made of stainless steel, which melts at 2,500°F—a much higher temperature than the aluminum components in other areas of the wing. Heavy slag buildup inside the RCC panels implied that the leading edge spar behind those panels melted and then was deposited as molten metal onto the surfaces of the panels. The edges of the retrieved pieces of RCC were heavily eroded and knife-edged—signs that plasma acting as a blowtorch at over 3,000°F was applied at high pressure to the panels over a prolonged period of time. This was the only place on the wing where this pattern was observed.
From panels 10 outward, more of the metallic fittings were found, and there was less slag and no erosion.
Materials scientists analyzed cross sections of the slag deposits inside the left wing panels to determine what materials they were made of and how the deposits were laid down. There were several layers of material, which told the story of the wing’s failure in time sequence. As more of the wing structure melted, the different types of metals from various parts of the wing were deposited in layers on top of the material already laid down on the inside of the panels.22
The location of the debris on the ground provided yet more evidence of how the shuttle came apart. Wreckage from the wings was not distributed randomly across East Texas. For example, the leading edge components from the middle to the tip of the left wing (panels 8 to 22) were found in the farthest west part of the debris field, between Dallas and Palestine. The leading edge pieces from the part of the left wing closest to the orbiter body (panels 1 to 7) came down between Palestine and Nacogdoches. The right wing leading edge pieces were the farthest east, scattered between Palestine and Hemphill. This provided evidence that the left wing failed before the right wing, the most likely failure point being near RCC panel 8 or 9.23
By late April, the story told by the debris was inescapable. The breach in the left wing was clearly in the wing’s leading edge, at panel 8 or 9.
The data team and debris team both concluded that a breach in Columbia’s left wing near RCC panel 8 or 9 allowed plasma to enter the wing. Flowing at several thousand miles per hour and with a temperature well in excess of 3,000°F, the plasma acted like a blowtorch and melted much of the wing’s support structure in the shaded area of this diagram.
On May 1, NASA announced that only one single failure scenario would explain all of the evidence contained in the debris, the OEX recorder, the telemetry received in Houston, and the videos provided by the public and other sources. Something—most likely the collision with the foam from the external tank—caused a breach in the leading edge of the left wing. This breach allowed plasma to penetrate the wing and erode it from the inside during the reentry. Whether the foam actually penetrated the leading edge—or if it pushed spacers apart and created a gap in the panels—will never be known.
The mystery of Columbia’s demise had been conclusively solved.
The last truckload of debris arrived at the reconstruction hangar on May 6. Wreckage that had been strewn over thousands of square miles of forest and field—pieces that had been carefully collected by tens of thousands of searchers working in tough conditions for three months—was all here in this one place. The twisted, burned, and shattered debris had told an important story, one that would have been impossible to write without the collective efforts of so many dedicated people in East Texas and Louisiana and of the nation’s wildland firefighting teams.
In the end, Columbia’s debris represented hope for the future of the program. “Each piece was evidence of how hard Columbia fought to come home to us,” Pam Melroy said. “We saw every recovered piece as a victory.” Every piece of debris moved the reconstruction team closer to their goal: We will find the problem, fix it, and move forward in their honor.24
However, this was not the end of the story of the reconstruction hangar and the debris. This was just another intermediate stop on Columbia’s journey home.
PART IV
A BITTERSWEET VICTORY
We do not know where this journey will end, yet we know this: Human beings are headed into the cosmos.
—President George W. Bush, January 14, 2004
Chapter 12
HEALING AND CLOSURE
The long process of bringing closure to the story of Columbia began on February 11, 2003, when the final crew member was recovered in Sabine County. That same day, Ilan Ramon was buried at Moshav Nahalal in the Jezreel Valley in Israel. Rick Husband was buried in Amarillo, Texas, on February 21. A few days later, a memorial service was held for Kalpana Chawla at Zion National Monument in Utah, one of her favorite places. Willie McCool was buried in Anacortes, Washington, on March 4. Mike Anderson was buried on Friday, March 7, at Arlington National Cemetery. In a completely private gathering, President and Laura Bush spent nearly two hours with the families at the White House after Anderson’s service. After they spent an hour in conversation in the Oval Office, the president personally took them on an impromptu hour-long tour of the residence.1
On what would have been her forty-second birthday, Laurel Clark was laid to rest at Arlington on March 10. Dave Brown was interred nearby on March 12. Clark, Anderson, and Brown’s graves are near the Columbia Memorial and within a short distance of where the Challenger astronauts are interred. Dave Brown’s brother Doug held a celebration of Dave’s life after his interment. The family and friends tried to keep the mood light—an occasion to swap funny stories about Dave and the impact he had on their lives.
During the celebration, Doug took Ann Micklos aside and said, “I’m not supposed to tell you this, but—they found your watch.” She was floored.
Because of the privacy surrounding the crew module reconstruction area, none of the workers in the rest of the hangar knew anything about the crew’s personal effects that had been recovered. As she talked to Doug, Micklos learned that many personal items had already been returned to each of the crew’s spouses. NASA told Doug about the watch. But because of Ann’s “unofficial” relationship with Dave, she was not considered a family member. Protocol prevented NASA from releasing information about the recovered watch or returning it to her.
Doug fully supported her getting the watch back, and he helped start the paperwork to have it released to her. At the end of April, he called her to say that he had the watch in hand. She asked him to overnight it to her.
As she opened the package and inspected its contents, the condition of the watch amazed her. The leather band had burned away during reentry, and the crystal had shattered. However, the face of the watch was intact. The hands had stopped at 9:06—either when the crew mod
ule broke up or when the watch impacted the ground. Momentarily putting aside the sobering thoughts about what the watch had been through, Micklos laughed to herself that Dave had been thoughtful enough to set the watch to Eastern Time for her.
Micklos took the watch back to the reconstruction hangar to show Pam Melroy’s team she had received it. They were ecstatic to finally be able to discuss it with her. The watch had been processed through the crew module room, where it was treated like every other item of crew personal effects. The team had known for weeks it was hers, but they observed protocol and did not say anything to her about it. With the veil of secrecy finally lifted, everyone could celebrate the watch’s recovery and return.
Melroy told Micklos several other watches had also been recovered. Micklos’s watch, however, was the only one with the time of the accident preserved on its face. The crew module team had even debated as to whether that time indication could be used as evidence in the investigation. However, they concluded that because the watch was considered personal property and not official flight hardware, it could not be used for evidence.2
The story of the watch has one final chapter. On February 1, 2004—the first anniversary of the accident—Micklos asked to go out to the Shuttle Landing Facility runway with a couple of her colleagues to reflect on the loss of Columbia. USA shuttle landing technician Billy McClure volunteered to drive them.
Micklos went out onto the runway and had a moment of peace despite the morning’s heavy rain. Once back in the van, she and the group exchanged stories about their experiences with Columbia. McClure said he was one of the first responders from KSC to collect debris in Texas. He recalled walking along, scanning the ground, when something shiny caught his eye. He bent down to look at it, and saw it was a rectangular watch.
Micklos asked, “Did it have a blue face?” He said it did. Micklos was stunned. Out of all the people who searched for debris from Columbia, what were the odds that she would be in a van on the anniversary of the accident with the man who had found her watch? The astonishing coincidence brought everyone in the van to tears.
Bringing Columbia Home Page 24
