Bringing Columbia Home

by Michael D. Leinbach

  Many of the members of the prelaunch MMT then moved on to the “on-orbit” MMT. This MMT was supposed to meet regularly during a mission to assess any issues that arose during flight or could affect landing.

  Kennedy Space Center’s operational responsibility for a mission essentially ended once the shuttle had blasted off. However, KSC managers—including me, as launch director—participated in the on-orbit MMT. We focused on any issues that might affect preparations for the vehicle’s next mission once the shuttle returned from flight. Had something cropped up that would delay Columbia’s processing flow for her next flight? Were there any special issues that would require unusual servicing on the runway?

  The imagery analysis team reported the foam strike to the MMT on January 17, the second day of Columbia’s mission. Their initial conclusions were unprecedented. No one had ever seen such a large piece of foam come off the external tank and impact the orbiter during ascent. The analysts said it was a “big hit,” but no one knew how bad it was. It was just lightweight foam, but it may have hit the orbiter in a potentially dangerous location. The MMT did not appear concerned, but they asked for further analysis.

  Engineering teams examined the limited data they had at their disposal. The only computer program available was designed to model the impact of ice particles on the tiles on the orbiter’s underside. The software algorithms were not intended to assess damage from foam insulation strikes or hits on areas other than tiles. With so many unknowns, it was difficult to get consistent results from the analyses. The software’s appropriateness for use in this case was a stretch, but it was all that our analysts had to work with.

  The consequences of foam impacts on the RCC material on the leading edge of the wing were even more of an unknown. Reinforced carbon-carbon had a very hard surface, which some specialists considered too tough to be seriously damaged by foam impacts. Some engineers tried unsuccessfully several times to convince their colleagues that RCC was less forgiving than tile, but their objections largely went unappreciated. While someone could almost crush tiles in their hands, RCC felt like an extremely tough and capable material.

  Despite the application of the best minds to the problem, there was simply no reliable way to predict what the damage might be. Ann Micklos said, “We never had a clear picture of where the impact was. It was all assumptions. And you can’t solve a problem based on assumptions.”

  Robert Hanley and his boss Jerry Ross had returned to Houston after the launch. Hanley mentioned to Ross in a hallway conversation that he had heard reports about people investigating a possible debris strike on Columbia. Hanley said the word going around JSC was that the foam strike was a “nonissue.” Everyone thought foam was too lightweight to cause any serious damage.

  Ross replied to Hanley, “I’m not so sure.”

  Ross was recalling his experience as a crewman on Atlantis’s STS-27 mission, where hundreds of the orbiter’s tiles were heavily damaged during launch, and missing tile created a hole in the heatshield that nearly burned through on reentry. Atlantis held the distinction of being the most heavily damaged spaceship ever to survive reentry.2 And on STS-112, just four months before Columbia’s launch, a smaller piece of foam fell off the external tank and dented the metal ring attaching the left solid rocket booster (SRB) to the tank.

  The MMT discussed the foam strike at the four MMT meetings held during Columbia’s mission. The engineer presenting the issue to the MMT was new to his position. The MMT pressed him on data to back up his conclusions about potential damage to Columbia—in essence, “prove to us there’s a problem.” He responded that the team needed more data to make an accurate assessment.

  Engineers who had been with NASA since the early days of the shuttle recalled that national security assets had been called into service to photograph Columbia in orbit on her maiden flight in 1981. On that mission, as soon as the payload bay doors were opened once Columbia reached orbit, the crew and NASA noticed several tiles missing from the area near the shuttle’s tail. It was not public knowledge at the time, but NASA had reached out to the intelligence community to take images of Columbia in orbit and determine if other tiles were missing in critical areas not visible to the crew. How those images were obtained, and what they were able to show, is still classified information.

  People who remembered that situation reached out to contacts in the intelligence community and asked if it was possible to take similar images now. Mid-level technical experts in the intelligence community said they would be happy to help. They just needed a formal request from NASA.

  In one of the most confounding breakdowns of the management process for STS-107, the MMT refused to issue a formal request for images. In essence, the reasoning was: “You don’t have enough data on the problem to warrant getting the intelligence community involved.” And yet there was no way for the team to gather more data without the intelligence imagery. The imaging capabilities possessed by the intelligence community were highly classified and could not be used as justification for the request, because most of the team was not cleared to hear that information. Trapped in a Catch-22, those who desperately wanted the additional information felt incredibly frustrated at the bureaucratic logjam.

  Lower-level engineers at KSC and at Boeing’s shuttle design offices in Huntington Beach, California, adamantly insisted that the foam impact had damaged the RCC. Some refused to certify that the vehicle was safe to come home. The MMT noted and then overruled their objections. The discussions were not even reflected in the MMT’s meeting minutes.

  The MMT members convinced themselves there was nothing to be overly concerned about for Columbia’s reentry. Rather than digging into the possibilities of what could go wrong, they reassured one another that everything would be all right.

  “Prove to me that it’s not safe to come home” demonstrates a very different management culture than does “prove to me that it is safe to come home.” The former attitude quashes arguments and debates when there is no hard evidence to support a concern. It allows people to talk themselves into a false sense of security. The latter encourages exploration of an issue and development of contingencies.

  In hindsight, many of us who participated in the debate and decisions—myself included—blamed ourselves for not pressing the issue about the foam strike. However, it simply did not occur to most of us at the time that the crew might be in danger. Complacency and past experience lulled us into believing that the shuttle would get her crew home safely—just as she had done more than one hundred times previously—despite the knocks and dings. Management assumed that if there really were a problem, the “smart people” who were looking at it would speak up. Managers seemed not to comprehend that objections had in fact been raised and then brushed aside. Pressing on with the mission so that NASA could get back to space station assembly flights just seemed like the right thing to do.

  The crew was not even told about the foam strike until January 23—one week into the mission—and then only to prepare them for a question that might arise in an upcoming press conference. Mission Control sent an email to Rick Husband and Willie McCool informing them about the hit and immediately downplaying any worries: “Experts have reviewed the high speed photography and there is no concern for RCC or tile damage. We have seen this same phenomenon on several other flights and there is absolutely no concern for entry.”3

  Even if the astronauts had been asked to look for damage, they could not have shed light on the situation without taking extraordinary measures. Most of the front of the wing was not visible from the windows in the cockpit. The orbiter was not carrying its robotic arm in the payload bay, because the arm was not needed for this mission. Had that arm, with its multiple television cameras, been available, the crew could have scanned the top and front of the wing for damage. Even so, the arm would not have been able to reach underneath the orbiter to look for damage there.

  The only other way the crew could have checked the wing for damage would have been to take
a space walk. That would have required a two-day interruption to the science activities in Spacehab. The pressurized tunnel to Spacehab was on the other side of the air lock in the crew compartment. The crew would have had to seal off Spacehab while preparing for and conducting the space walk.

  So, the MMT did not ask the crew to inspect the orbiter. The MMT incorrectly concluded that no significant damage existed. Besides, the MMT reasoned, there was nothing the crew could have done about it anyway. The MMT flatly declared that there was no “safety of flight” issue involved—that is, no risk for reentry. Any damage to the thermal protection system would just be a turnaround maintenance problem for the next mission once Columbia was back on the ground.

  The US Air Force’s Maui Optical and Supercomputer Site (AMOS) took images of Columbia as it passed over Hawaii on January 28. The orbiter’s payload bay was facing the cameras on the ground. The Spacehab module was clearly visible in the payload bay. Unfortunately, the open bay doors obstructed the view of the front half of Columbia’s wing, where the foam was thought to have struck the ship. The resolution of the AMOS cameras was probably not good enough to have captured wing damage anyway.

  That same day—the seventeenth anniversary of the Challenger accident—Rick Husband and his crew paused to remember the crews of Challenger and Apollo 1. Husband said, “They made the ultimate sacrifice, giving their lives in service to their country and for all mankind. Their dedication and devotion to the exploration of space was an inspiration to each of us and still motivates people around the world to achieve great things in service to others. As we orbit the Earth, we will join the entire NASA family for a moment of silence in their memory. Our thoughts and prayers go to their families as well.”4

  —

  Unknown to NASA at the time—and even to the people manning the intelligence assets that acquired the images—the US military had inadvertently obtained evidence of something breaking away from Columbia on the second day of her flight.

  The Space Surveillance Network (SSN), which was operated jointly by the US Army, Navy, and Air Force, was a worldwide network of sensing systems designed to track objects in orbit around Earth. Early in the postmortem of the Columbia accident, SSN analysts went back over their tracking data to see if they had obtained any information about Columbia and any objects that might have collided with her in orbit. The analysts noticed that another object was in the same orbit as Columbia beginning on the second day of the mission.

  After refining the radar data, the analysts determined that a slow-moving object, about the size of a laptop computer, gradually drifted away from the shuttle. Its slow motion implied that it was probably not a piece of space junk or a meteor. Further tests showed that the radar properties of the object were a close match for a piece of RCC panel—possibly part of the wing’s leading edge. It appeared to separate from the shuttle after several thruster firings that changed Columbia’s orbital orientation.

  Whatever it was, the object reentered the Earth’s atmosphere and burned up on January 20, twelve days before the end of Columbia’s mission. Theories about the object and its origin were debated at length during the accident investigation, but its exact nature and possible relevance to Columbia’s demise will never be known.

  Again, no one knew anything about this object during the mission. Could this information have changed the course of events? That will also never be known.

  —

  As Columbia approached the end of her time in orbit, some people at KSC began to worry about how to bring her home safely. If the thermal tiles had significant damage, Columbia would need to keep its temperature down as much as possible during reentry.

  Weight was an immediate concern. As the first ship in the fleet, Columbia was already heavier than her sister shuttles. The added mass of the Spacehab module meant that STS-107 would be the heaviest shuttle ever to return from orbit. That would make her reentry hotter than usual, even if everything went as planned.

  Some people at KSC openly asked, “Can we jettison the payload to make the vehicle lighter?” Even if that were possible—and it was not—it would have meant the loss of many of the science experiments and their data. Management did not seriously consider the recommendations to throw overboard all “loose objects” in the crew module and Spacehab, especially with the official determination that there was no concern for flight safety.5

  Ed Mango, my assistant launch director, had supported “Hoot” Gibson and Jerry Ross’s STS-27 mission early in his career at NASA. Recalling how badly beat up Atlantis was on that mission, Mango expected that Columbia would also make it back to the landing site, but would probably be heavily damaged. He requested permission in advance to go out to the runway after the vehicle was “safed” so that he could inspect the ship personally.

  Ann Micklos said, “Putting on my engineering hat, we were interested to see what the vehicle was going to look like when it came back. I thought she could handle reentry with the damage. I trusted the team that provided the ‘go for entry.’ However, our team was also planning how we were going to turn the vehicle around on the ground to get it ready for [missions to the International Space] Station. None of us in our wildest thoughts believed that things would turn out the way they did.”

  Pressure to keep on schedule had combined with a complacency brought about by so many past mission successes. The same conditions were present for Apollo 1 and Challenger. And once again, a crew would pay with their lives.

  Chapter 4

  LANDING DAY

  8:15 a.m. EST

  As Saturday, February 1, 2003, dawned, NASA teams at Kennedy Space Center and Johnson Space Center prepared to bring Columbia home at the end of her sixteen-day mission. Orbiting 173 miles above Earth,1 Columbia’s crew stowed their experiments in lockers and closed and latched Columbia’s payload bay doors. The crew donned their launch and entry pressure suits and helmets. These orange “pumpkin” suits could provide protection and oxygen in case the cabin lost pressure during reentry or the crew had to make an emergency bailout.2

  The astronauts took their positions in the crew module. On the flight deck, Rick Husband sat in the commander’s seat, with pilot Willie McCool to his right. Kalpana Chawla sat in the jump seat, behind and centered between Husband and McCool. To her right was Laurel Clark. These four astronauts had the best view during reentry, as all of the shuttle’s large windows were on the flight deck. The three crewmen seated in the shuttle’s mid-deck (seated from left, Mike Anderson, Dave Brown, and Ilan Ramon) could see only the stowage lockers directly in front of them.

  Columbia could land either at Kennedy or at Edwards Air Force Base in California, depending on the weather in Florida. NASA had to make the landing site decision about two hours in advance, because the de-orbit burn needed to happen halfway around the world from the landing site and one hour before touchdown.

  The weather forecast at Kennedy looked favorable, so Commander Husband was given the “Go” to come home to KSC. He fired Columbia’s orbital maneuvering system engines over the Pacific Ocean at 8:15:30. This would drop the ship out of orbit and direct her toward Florida, with a touchdown at 9:16 Eastern Time. She would come in to Kennedy’s Shuttle Landing Facility—the SLF—one of the world’s longest runways.

  Columbia gradually fell out of orbit and became an unpowered glider in the atmosphere. Now irrevocably committed to land at KSC, there was no option to go around again or look for another spaceport.

  Launch and Entry Flight Director LeRoy Cain and his Flight Control team in Houston were managing the last stages of the flight. They monitored telemetry from the vehicle and communicated with the crew. They would continue to command the mission until Columbia’s crew disembarked at Kennedy.

  Outside Mission Control, the rest of Johnson Space Center was almost a ghost town as this cool, foggy day dawned. People who were not involved in mission operations for Columbia or the International Space Station were at home for the weekend. Andy Thomas, deputy chief of the astronaut o
ffice, was on routine duty in Building 4 South that morning, manning the contingency action center. There would normally be very little for him to do.

  I arrived at Kennedy’s Launch Control Center at seven o’clock to monitor the de-orbit burn. Ed Mango was there, as was Don Hamel, controlling Kennedy’s landing operations. Mango came in that morning to fill in for a vacationing colleague. He told his wife to expect him home by ten-thirty, after Columbia was securely in the hands of the landing and recovery team. Our main role as managers was to deploy the landing and recovery forces to assist the crew and power down Columbia after she landed. Nearly two hundred people crowded into the Firing Rooms on launch day. But on landing day, things felt almost deserted, with only about fifty people on hand.

  I watched the proceedings on one of my computer monitors, and I saw that the de-orbit burn occurred on schedule and without problems. I then raced out to the Shuttle Landing Facility runway, about two miles north, to join other VIPs and guests gathering to greet Columbia. I did not want to get stuck waiting for the convoy of landing support vehicles to trundle across the roadway. They had also departed their staging area for the runway when they heard that the de-orbit burn was successful.

  Columbia began encountering the upper reaches of the atmosphere. Her path would take her east-southeast across California, Nevada, Utah, Arizona, New Mexico, Texas, and Louisiana. Then she would skirt the Gulf Coast as she lined up for the approach to the runway.

  As she made her way across the southern United States over the course of twenty minutes, Columbia would lose her last forty-four miles in altitude and slow from sixteen thousand miles per hour to zero at “wheels stop.” Columbia’s automated flight control system ran all aspects of the flight during reentry, banking and rolling the orbiter to control its speed and energy profile during the period of maximum heating. Rick Husband would take the control stick only in the final couple of minutes of the approach and landing sequence.