Come to think of it, that article ought to be mirrored somewhere. (It's all text, so what-the-hey.)
http://www.guardian.co.uk/columbia/story/0,12845,1120962,00.html
The problem with Houston
What is known is that four seconds after 8 o'clock on the morning of 1 February 2003, the Columbia shuttle started to break up. Flying at 200,000ft and at 12,738mph, none of its crew would survive... What wasn't known, until now, is why. William Langewiesche reports
Sunday January 11, 2004
The Observer
Space flight is known to be a risky business, but during the minutes before dawn last 1 February, as the doomed shuttle Columbia began to descend into the upper atmosphere over the Pacific Ocean, only a handful of people - a few engineers deep inside Nasa - worried that the vehicle and its seven souls might actually come to grief. It was the responsibility of Nasa's managers to hear those suspicions, and from top to bottom they failed. After the fact, that's easy to see. But in fairness to those whose reputations have now been sacrificed, 17 years and 89 shuttle flights had passed since the Challenger explosion, and within the agency a new generation had risen that was smart, perhaps, but also unwise - confined by Nasa's walls and routines, and vulnerable to the self-satisfaction that inevitably had set in.
Article continues
Moreover, this mission was a yawn-a low-priority 'science' flight forced on to Nasa by Congress and postponed for two years because of a more pressing schedule of construction deliveries to the International Space Station. The truth is, it had finally been launched as much to clear the books as to add to human knowledge, and it had gone nowhere except into low earth orbit, around the globe every 90 minutes for 16 days, carrying the first Israeli astronaut and performing a string of experiments, many of which, like the shuttle programme itself, seemed to suffer from something of a make-work character - the examination of dust in the Middle East (by the Israeli, of course); the ever-popular ozone study; experiments designed by schoolchildren in six countries to observe the effect of weightlessness on spiders, silkworms and other creatures; an exercise in 'astroculture' involving the extraction of essential oils from rose and rice flowers, which was said to hold promise for new perfumes, and so forth. No doubt some good science was done, too - particularly pertaining to space flight itself - though none of it was so urgent that it could not have been performed later, under better circumstances, in the under-booked International Space Station. The astronauts aboard the shuttle were smart and accomplished people, and they were deeply committed to human space flight and exploration. They were also team players, by intense selection, and nothing if not wise to the game. From orbit one of them had radioed: 'The science we're doing here is great, and it's fantastic. It's leading-edge.' Others had dutifully reported that the planet seems beautiful, fragile and borderless when seen from such altitudes, and they had expressed their hopes in English and Hebrew for world peace. It was Miracle Whip on Wonder Bread, standard Nasa fare. On the ground so little attention was being paid that even the radars that could have been directed upward to track Columbia's re-entry into the atmosphere - from Vandenberg Air Force Base, or White Sands Missile Range - were sleeping. As a result, no radar record of the breakup exists - only of the metal rain that drifted down over East Texas, and eventually came into the view of air-traffic control.
Along the route, however, stood small numbers of shuttle enthusiasts, who had got up early with their video cameras and had arrayed themselves on hills or away from city lights to record the spectacle. The shuttle came into view, on track and on schedule, just after 5.53 Pacific time, crossing the California coast at about 15,000mph in the superthin air 230,000ft above the Russian River, northwest of San Francisco. It was first picked up on video by a Lockheed engineer in suburban Fairfield, who recorded a bright meteor passing almost directly overhead, not the shuttle itself but the sheath of hot gases around it, and the long, luminous tail of ionised air known as plasma. Only later, after the engineer heard about the accident on television, did he check his tape and realise that he had recorded what appeared to be two pieces coming off Columbia in quick succession, like little flares in its wake. Those pieces were recorded by others as well, along with the third, fourth and fifth 'debris events' that occurred during the 60 seconds that it took the shuttle to cross California. From the top of Mount Hamilton, southeast of San Francisco, another engineer, the former president of the Peninsula Astronomical Society, caught all five events on tape. He later said, 'I'd seen four re-entries before this one. When we saw it, we did note that it was a little brighter and a bit whiter than it normally is. It's normally a pink-magenta colour. But you know, it wasn't so different that it really flagged us as something wrong. With the naked eye we didn't see the particles coming off.'
One minute after Columbia left California, as it neared southwestern Utah, the trouble was becoming more obvious to observers on the ground. There had been a bright flash earlier over Nevada, and now debris came off that was large enough to cause multiple secondary plasma trails. North of the Grand Canyon, in Saint George, Utah, a man and his grown son climbed on to a ridge above the county hospital, hoping for the sort of view they had seen several years before, of a fireball going by. It was a sight they remembered as 'really neat'. This time was different, though. The son, who was videotaping, started yelling, 'Jesus, Dad, there's stuff falling off!' and the father saw it too, with his naked eyes.
Columbia was flying on autopilot, as is usual, and though it continued to lay flares in its wake, the astronauts aboard remained blissfully unaware of the trouble they were in. They passed smoothly into dawn above the Arizona border, and sailed across the Navajo reservation and on over Albuquerque, before coming to the Texas Panhandle on a perfect descent profile, slowing through 13,400mph at 210,000ft five minutes after having crossed the California coastline. Nineteen seconds later, at 7:58:38 Central time, they got the first sign of something being a little out of the ordinary: it was a cockpit indication of low tyre pressures on the left main landing gear. This was not quite a trivial matter. A blown or deflated main tyre would pose serious risks during the rollout after landing, including loss of lateral control and the possibility that the nose would slam down, conceivably leading to a catastrophic breakup on the ground. These scenarios were known, and had been simulated and debated in the inner world of Nasa, leading some to believe that the best of the imperfect choices in such a case might be for the crew to bail out - an alternative available only below 30,000ft and 220mph of dynamic airspeed.
Nonetheless, for Columbia's pilots it was reasonable to assume for the moment that the indication of low pressure was due to a problem with the sensors rather than the tyres, and that the teams of Mission Control engineers at Nasa's Johnson Space Center, in Houston, would be able to sort through the mass of automatically transmitted data - the so-called telemetry, which was far more complete than what was available in the cockpit - and to draw the correct conclusion. The reverse side of failures in a machine as complex as the shuttle is that most of them can be worked around, or turn out to be small. In other words, there was no reason for alarm. After a short delay, Columbia's commander, Rick Husband, calmly radioed to Mission Control, 'And, ah, Houston...' Sheathed in hot atmospheric gases, the shuttle was slowing through 13,100mph at 205,000ft.
Houston did not clearly hear the call.
With the scheduled touchdown now only about 15 minutes ahead, it was a busy time at Mission Control. Weather reports were coming in from the landing site at the Kennedy Space Center, in Florida. Radar tracking of the shuttle, like the final accurate ground-based navigation, had not yet begun. Sitting at their specialised positions, and monitoring the numbers displayed on the consoles, a few of the flight controllers had begun to sense, just barely, that something was going seriously wrong. The worry was not quite coherent yet. One of the controllers later told me that it amounted to an inexplicable bad feeling in his gut. But it was undeniable nonetheless. For the previous few minutes, since about the time when the shuttle had passed from California to Nevada, Jeff Kling, an engineer who was working the mechanical-systems position known as MMACS (pronounced Macs), had witnessed a swarm of erratic indications and sensor failures. The pattern was disconcerting because of the lack of common circuitry that could easily explain the pattern of such failures - a single box that could be blamed.
Kling had been bantering good-naturedly on an intercom with one of his team, a technician sitting in one of the adjoining back rooms and monitoring the telemetry, when the technician noted a strange failure of temperature transducers on a hydraulic return line. The technician said, 'We've had some hydraulic 'ducers go off-scale low.'
Kling had seen the same indications. He said, 'Well, I guess!'
The technician said, 'What in the world?'
Kling said, 'This is not funny. On the left side.'
The technician confirmed, 'On the left side...'
Now Kling got on to the main control-room intercom to the lead controller on duty, known as the flight director, a man named Leroy Cain. In the jargon-laced language of the control room Kling said, 'Flight, Macs.'
Cain said, 'Go ahead, Macs.'
'FYI, I've just lost four separate temperature transducers on the left side of the vehicle, hydraulic return temperatures. Two of them on system one, and one in each of systems two and three.'
Cain said, 'Four hyd return temps?'
Klling answered, 'To the left outboard and left inboard elevon.'
'OK, is there anything common to them? DSC or MDM or anything? I mean, you're telling me you lost them all at exactly the same time?'
'No, not exactly. They were within probably four or five seconds of each other.'
Cain struggled to assess the meaning. 'OK, where are those... where is that instrumentation located?'
Kling continued to hear from his back-room team. He said, 'All four of them are located in the aft part of the left wing, right in front of the elevons... elevon actuators. And there is no commonality.'
Cain repeated, 'No commonality.'
But all the failing instruments were in the left wing. The possible significance of this was not lost on Cain: during the launch a piece of solid foam had broken off from the shuttle's external fuel tank, and at high speed had smashed into the left wing; after minimal consideration the shuttle programme managers (who stood above Mission Control in the Nasa hierarchy) had dismissed the incident as essentially unthreatening. Like almost everyone else at Nasa, Cain had taken the managers at their word - and he still did. Nonetheless, the strange cluster of left-wing failures was an ominous development. Kling had more specific reasons for concern. In a wonkish, engineering way he had discussed with his team the telemetry they might observe if a hole allowed hot gases into the wing during re-entry, and had come up with a profile eerily close to what was happening now. Still, he maintained the expected detachment.
Cain continued to worry the problem. He asked for reassurance from his 'guidance, navigation, and control' man, Mike Sarafin. 'Everything look good to you, control and rates and everything is nominal, right?'
Sarafin said, 'Control's been stable through the rolls that we've done so far, Flight. We have good trims. I don't see anything out of the ordinary.'
Cain directed his attention back to Kling: 'All other indications for your hydraulic systems indications are good?'
'They're all good. We've had good quantities all the way across.'
Cain said, 'And the other temps are normal?'
'The other temps are normal, yes, sir.' He meant only those that the telemetry allowed him to see.
Cain said, 'And when you say you lost these, are you saying they went to zero...'
'All four of them are off-scale low.'
'...or off-scale low?'
Kling said, 'And they were all staggered. They were, like I said, within several seconds of each other.'
Cain said, 'OK.'
But it wasn't OK. Within seconds Columbia had crossed into Texas and the left-tyre-pressure indications were dropping, as observed also by the cockpit crew. Kling's informal model of catastrophe had predicted just such indications, whether from blown tyres or wire breaks. The end was now coming very fast.
Kling said, 'Flight, Macs.'
Cain said, 'Go.'
'We just lost tyre pressure on the left outboard and left inboard, both tyres.'
Cain said, 'Copy.'
At that moment, 23 seconds after 7.59am local time, the Mission Control consoles stopped receiving telemetry updates, for reasons unknown. The astronaut sitting beside Cain, and serving as the Mission Control communicator, radioed, 'And Columbia, Houston, we see your tyre-pressure messages, and we did not copy your last call.'
At the same time, on the control-room intercom, Cain was talking again to Kling. He said, 'Is it instrumentation, Macs? Gotta be.'
Kling said, 'Flight, Macs, those are also off-scale low.'
From the speeding shuttle Rick Husband - Air Force test pilot, religious, good family man, always wanted to be an astronaut - began to answer the communicator. He said, 'Roger, ah,' and was cut off on a word that began with 'buh...'
It turned out to be Columbia's last voice transmission. Brief communication breaks, however, are not abnormal during re-entries, and this one raised no immediate concern in Houston.
People on the ground in Dallas suddenly knew more than the flight controllers in Houston. Four seconds after 8am they saw a large piece leave the orbiter and fall away. The shuttle was starting to come apart. It continued intermittently to send telemetry, which though not immediately displayed at Mission Control was captured by Nasa computers and later discovered; the story it told was that multiple systems were failing. In quick succession two additional chunks fell off.
Down in the control room Cain said, 'And there's no commonality between all these tyre-pressure instrumentations and the hydraulic return instrumentations?'
High in the sky near Dallas, Columbia's main body began to break up. It crackled and boomed, and made a loud rumble.
Kling said, 'No, sir, there's not. We've also lost the nose-gear down talkback, and right-main-gear down talkback.'
'Nose-gear and right-main-gear down talkbacks?'
'Yes, sir.'
At Fort Hood, Texas, two Dutch military pilots who were training in an Apache attack helicopter locked on to the breakup with their optics and videotaped three bright objects - the main rocket engines - flying eastward in formation, among other, smaller pieces and their contrails.
Referring to the loss of communications, one minute after the main-body breakup, Laura Hoppe, the flight controller responsible for the communications systems, said to Cain, 'I didn't expect, uh, this bad of a hit on comm.'
Cain asked another controller about a planned switchover to a ground-based radio ahead, 'How far are we from UHF? Is that two-minute clock good?'
Kling, also, was hanging on to hope. He said, 'Flight, Macs.'
Cain said, 'Macs?'
Kling said, 'On the tyre pressures, we did see them go erratic for a little bit before they went away, so I do believe it's instrumentation.'
'OK.'
At about that time the debris began to hit the ground. It fell in thousands of pieces along a swath 10 miles wide and 300 miles long, across East Texas and into Louisiana. There were many stories later. Some of the debris whistled down through the leaves of trees and smacked into a pond where a man was fishing. Another piece went right through a backyard trampoline, evoking a mother's lament: 'Those damn kids...' Still another piece hit the window of a moving car, startling the driver. The heaviest parts flew the furthest. An 800lb piece of engine hit the ground in Fort Polk, Louisiana, doing 1,400mph.
A 600lb piece landed nearby. Thousands of people began to call in, swamping the 911 dispatchers with reports of sonic booms and metal falling out of the sky. No one, however, was hit. This would be surprising were it not for the fact, so visible from above, that the world is still a sparsely populated place.
In Houston the controllers maintained discipline and continued preparing for the landing, even as they received word that the Merritt Island radar, in Florida, which should by now have started tracking the inbound craft, was picking up only false targets. Shuttles arrive on time or they don't arrive at all. But, repeatedly, the communicator radioed: 'Columbia, Houston, UHF comm check,' as if he might still hear a reply. Then, at 13 minutes past the hour, precisely when Columbia should have been passing over the runway before circling down for a landing at the Kennedy Space Center, a phone call came in from an off-duty controller who had just seen a video broadcast by a Dallas television station of multiple contrails in the sky. When Cain heard the news, he paused, and then put the contingency plan into effect. To the ground- control officer he said, 'GC, Flight.'
'Flight, GC.'
'Lock the doors.'
'Copy.'
The controllers were stunned, but lacked the time to contemplate the horror of what had just happened. Under Cain's direction they set about collecting numbers, writing notes and closing out their logs for the investigation that was certain to follow. The mood in the room was sombre and focused. Only the most basic facts were known: Columbia had broken up at 200,000ft doing 12,738mph, and the crew could not possibly have survived. Ron Dittemore, the shuttle programme manager, would be talking to reporters later that day, and he needed numbers and information. At some point sandwiches were brought in and consumed. Like the priests who harvest faith at the bedsides of the dying, grief counsellors showed up, too, but they were not much used.
Cain insisted on control-room discipline. He said, 'No phone calls off site outside of this room. Our discussions are on these loops - the recorded DVIS loops only. No data, no phone calls, no transmissions anywhere, into or out.'
Later this was taken by some critics to be a typical Nasa reaction - insular, furtive, overcontrolling. And it may indeed have reflected certain aspects of what had become of the agency's culture. But it was also, more simply, a rule-book procedure meant to stabilise and preserve the crucial last data. The room was being frozen as a crime scene might be.
Less than an hour later, at 10am Eastern time, a retired four-star admiral named Hal Gehman met his brother at a lawyer's office in Williamsburg, Virginia. At the age of 60, Gehman was a tall, slim, silver-haired man with an unlined face and soft eyes. Dressed in civilian clothes, standing straight but not stiffly so, he had an accessible, unassuming manner that contrasted with the rank and power he had achieved. After an inauspicious start as a mediocre engineering student in the Penn State Naval ROTC programme ('Top four-fifths of the class,' he liked to say), he had skippered a patrol boat through the thick of the Vietnam War and gone on to become an experienced sea captain, the commander of a carrier battle group, vice-chief of the Navy, and finally Nato Atlantic commander and head of the US Joint Forces Command. Upon his retirement, in 2000, from the sixth-ranked position in the US military, he had given all that up with apparent ease. He had enjoyed a good career in the Navy, but he enjoyed his civilian life now, too. He was a rare sort of man - startlingly intelligent beneath his guileless exterior, personally satisfied, and quite genuinely untroubled. He lived in Norfolk in a pleasant house that he had recently remodeled; he loved his wife, his grown children, his mother and father, and all his siblings. He had an old Volkswagen bug convertible, robin's-egg blue, that he had bought from another admiral. He had a modest 34ft sloop, which he enjoyed sailing in the Chesapeake, though its sails were worn out and he wanted to replace its icebox with a 12-volt refrigeration unit. He was a patriot, of course, but not a reactionary. He called himself a fiscal conservative and a social moderate. His life as he described it was the product of convention. It was also the product of a strict personal code. He chose not to work with any company doing business with the Department of Defense. He liked power, but understood its limitations. He did not care to be famous or rich. He represented the American establishment at its best.
In the lawyer's office in Williamsburg his brother told him that Columbia had been lost. Gehman had driven there with his radio off and so he had not heard. He asked a few questions, and absorbed the information without much reaction. He did not follow the space programme and, like most Americans, had not been aware that a mission was under way. He spent an hour with the lawyer on routine family business. When he emerged, he saw that messages had been left on his cell phone, but because the coverage was poor, he could not retrieve them; only later, while driving home on the interstate, was he finally able to connect. To his surprise, among mundane messages he found an urgent request to call the deputy administrator of Nasa, a man he had not heard of before, named Fred Gregory. Like a good American, Gehman made the call while speeding down the highway. Gregory, a former shuttle commander, said, 'Have you heard the news?'
Gehman said, 'Only secondhand.'
Gregory filled him in on what little was known, and explained that part of Nasa's contingency plan, instituted after the Challenger disaster of 1986, was the activation of a standing 'interagency' investigation board. By original design the board consisted of seven high-ranking civilian and military officials who were pre-selected mechanically on the basis of job titles - the institutional slots that they filled. For Columbia, the names were now known: the board would consist of three Air Force generals, John Barry, Kenneth Hess and Duane Deal; a Navy admiral, Stephen Turcotte; a Nasa research director, G Scott Hubbard; and two senior civil-aviation officials, James Hallock and Steven Wallace. Though only two of these men knew much about Nasa or the shuttle, each of them was familiar with the complexities of large-scale, high-risk activities. Most of them also had strong personalities. To be effective they would require even stronger management. Gregory said that it was Nasa's administrator, Sean O'Keefe, who wanted Gehman to come in as chairman to lead the work. Gehman was not immune to the compliment, but he was cautious. He had met O'Keefe briefly years before, but did not know him. He wanted to make sure he wasn't being suckered into a Nasa sideshow.
O'Keefe was an able member of Washington's revolving-door caste, a former congressional staffer and budget specialist - and a longtime protege of Vice President Dick Cheney - who through the force of his competence and Republican connections had briefly landed the position of Secretary of the Navy in the early 1990s. He had suffered academic banishment through the Clinton era, but under the current administration had re-emerged as a deputy at the Office of Management and Budget, where he had been assigned to tackle the difficult problem of Nasa's cost overruns and lack of delivery, particularly in the Space Station programme. It is hard to know what he thought when he was handed the treacherous position of Nasa administrator. Inside Washington, Nasa's reputation had sunk so low that some of O'Keefe's former congressional colleagues snickered that Cheney was trying to kill his own man off. But O'Keefe was not a space crusader, as some earlier Nasa administrators had been, and he was not about to pick up the fallen banners of the visionaries and try to lead the way forward; he was a tough, level-headed money man, grounded in the realities of Washington, DC, and sent in on a mission to bring discipline to Nasa's budget and performance before moving on. Nasa's true believers called him a carpetbagger and resented the schedule pressures that he brought to bear, but in fairness he was a professional manager, and Nasa needed one.
O'Keefe had been at Nasa for just over a year when Columbia self-destructed. He was in Florida standing at the landing site beside one of his deputies, a former shuttle commander named William Readdy. At 9.05 Eastern time, 10 minutes before the scheduled landing, Readdy got word that communications with the shuttle, which had been lost, had not been re-established; O'Keefe noticed that Readdy's face went blank. At 9.10 Readdy opened a book to check a time sequence. He said, 'We should have heard the sonic booms by now. There's something really wrong.' By 9.29 O'Keefe had activated the full-blown contingency plan. When word got to the White House, the executive staff ducked quickly into defensive positions: President Bush would grieve alongside the families and say the right things about carrying on, but rather than involving himself by appointing an independent presidential commission, as Ronald Reagan had in response to the Challenger accident, he would keep his distance by expressing faith in Nasa's ability to find the cause. In other words, this baby was going to be dropped squarely on to O'Keefe's lap. The White House approved Gehman's appointment to lead what would essentially be Nasa's investigation - but O'Keefe could expect little further communication. There was a chance that the President would not even want to receive the final report directly but would ask that it be deposited more discreetly in the White House in-box. He had problems bigger than space on his mind.
Nonetheless, that morning in his car Gehman realised that even with a lukewarm White House endorsement, the position that Nasa was offering, if handled correctly, would allow for a significant inquiry into the accident. Gregory made it clear that Gehman would have the full support of Nasa's engineers and technical resources in unraveling the physical mysteries of the accident - what actually had happened to Columbia out there in its sheath of fire at 200,000ft. Moreover, Gehman was confident that if the investigation had to go further, into why this accident had occurred, he had the experience necessary to sort through the human complexities of Nasa and emerge with useful answers that might result in reform. This may have been overconfident of him, and to some extent utopian, but it was not entirely blind: he had been through big investigations before, most recently two years earlier, just after leaving the Navy, when he and retired Army general William Crouch had led an inquiry into the loss of 17 sailors aboard the USS Cole, the destroyer that was nearly sunk by suicide terrorists in Yemen in October 2000. Their report found fundamental errors in the functioning of the military command structure and issued recommendations (largely classified) that are in effect today. The success of the Cole investigation was one of the arguments that Gregory used on him now. Gehman did not disagree, but he wanted to be very clear. He said, 'I know you've got a piece of paper in front of you. Does it say that I'm not an aviator?'
Gregory said, 'We don't need an aviator here. We need an investigator.'
And so, driving down the highway to Norfolk, Gehman accepted the job. When he got home, he told his wife that he was a federal employee again and that there wouldn't be much sailing in the spring. That afternoon and evening, as the faxes and phone calls came in, he began to exercise control of the process, if only in his own mind, concluding that the board's charter as written by Nasa would have to be strengthened and expanded, and that its name should immediately be changed from the absurd International Space Station and Space Shuttle Mishap Interagency Investigations Board (ISSSSMIIB) to the more workable Columbia Accident Investigation Board, or CAIB, which could be pronounced in one syllable, as Cabe.
Nasa initially did not resist his suggestions. Gregory advised Gehman to head to Barksdale Air Force Base, in Shreveport, Louisiana, where the wreckage was being collected. As Gehman began to explore airline connections, word came that a Nasa executive jet, a Gulfstream, would be dispatched to carry him, along with several other board members, to Barksdale. The jet arrived in Norfolk on Sunday afternoon, the day after the accident. One of the members already aboard was Steven Wallace, the head of accident investigations for the FAA. Wallace is a second-generation pilot, an athletic, tightly wound man with wide experience in government and a sceptical view of the powerful. He later told me that when Gehman got on the airplane, he was dressed in a business suit, and that, having introduced himself, he explained that they might run into the press, and if they did, he would handle things. This raised some questions about Gehman's motivations (and indeed Gehman turned out to enjoy the limelight), but as Wallace soon discovered, grandstanding was not what Gehman was about. As the Gulfstream proceeded toward Louisiana, Gehman rolled up his sleeves and, sitting at the table in the back of the airplane, began to ask for the thoughts and perspectives of the board members there - not about what might have happened to Columbia but about how best to find out. It was the start of an intense seven-month relationship. It was obvious that Gehman was truly listening to the ideas, and that he was capable of integrating them quickly and productively into his own thoughts. By the end of the flight even Wallace was growing impressed.
But Gehman was in some ways also naive, formed as he had been by investigative experience within the military, in which much of the work proceeds behind closed doors, and conflict of interest is not a big concern. The Columbia investigation was going to be a very different thing. Attacks against the CAIB began on the second day, and by midweek, as the board moved to Houston to set up shop, they showed no signs of easing. Congress was thundering that Gehman was a captive investigator, that his report would be a whitewash, and that the White House should replace the CAIB with a Challenger-style presidential commission. This came as a surprise to Gehman, who had assumed that he could just go about his business but who now realised that he would have to accommodate these concerns if the final report was to have any credibility at all. Later he said to me, 'I didn't go in thinking about it, but as I began to hear the independence thing - "You can't have a panel appointed by Nasa investigating itself!" - I realised I'd better deal with Congress.' He did this at first mainly by listening on the phone. 'They told me what I had to do to build my credibility; I didn't invent it. They also said, "We hate Nasa. We don't trust them. Their culture is no good. And their cost accounting is no good." And I said, "OK."'
More than that, Gehman came to realise that it was the elected representatives in Congress - and neither O'Keefe nor Nasa - who constituted the CAIB's real constituency, and that their concerns were legitimate. As a result of this, along with a growing understanding of the complexity of the work at hand, he forced through a series of changes, establishing a congressional-liaison office, gaining an independent budget (ultimately about $20m), wresting the report from O'Keefe's control, re-writing the stated mission to include the finding of 'root causes and circumstances' and hiring an additional five board members, all civilians of unimpeachable reputation: the retired Electric Boat boss Roger Tetrault, the former astronaut Sally Ride, the Nobel-laureate physicist Douglas Osheroff, the aerodynamicist and former Air Force Secretary Sheila Widnall, and the historian and space-policy expert John Logsdon. Afterward, the loudest criticism faded away.
The foam did it. That much was suspected from the start, and all the evidence converged on it as the CAIB's investigation proceeded through the months that followed. The foam was dense and dry; it was the brownish-orange coating applied to the outside of the shuttle's large external tank to insulate the extreme cold of the rocket fuels inside from the warmth and moisture of the air. Eighty-two seconds after liftoff, as Columbia was accelerating through 1,500mph, a piece of that foam - about 19in long by 11in wide, weighing about 1.7lb - broke off from the external tank and collided with the left wing at about 545mph. Cameras near the launch site recorded the event - though the images when viewed the following day provided insufficient detail to know the exact impact point, or the consequences. The CAIB's investigation ultimately found that a gaping hole about 10in across had been punched into the wing's leading edge, and that 16 days later the hole allowed the hot gases of the re-entry to penetrate the wing and consume it from the inside. Through enormous effort this would be discovered and verified beyond doubt.
It was important nonetheless to explore the alternatives. In an effort closely supervised by the CAIB, groups of Nasa engineers created several thousand flow charts, one for each scenario that could have led to the re-entry breakup. The thinking was rigorous. For a scenario to be 'closed', meaning set aside, absolute proof had to be found (usually physical or mathematical) that this particular explanation did not apply: there was no cockpit fire, no flight-control malfunction, no act of terrorism or sabotage that had taken the shuttle down. Unexpected vulnerabilities were found during this process, and even after the investigation was formally concluded, in late August, more than 100 scenarios remained technically open, because they could not positively be closed. For lack of evidence to the contrary, for instance, neither bird strikes nor micrometeorite impacts could be completely ruled out.
But for all their willingness to explore less likely alternatives, many of Nasa's managers remained stubbornly closed-minded on the subject of foam. From the earliest telemetric data it was known that intense heat inside the left wing had destroyed Columbia, and that such heat could have got there only through a hole. The connection between the hole and the foam strike was loosely circumstantial at first, but it required serious consideration nonetheless. Nasa balked at going down that road. Its reasons were not rational and scientific but, rather, complex and cultural, and they turned out to be closely related to the errors that had led to the accident: simply put, it had become a matter of faith within Nasa that foam strikes - which were a known problem - could not cause mortal damage to the shuttle. Sean O'Keefe, who was badly advised by his Nasa lieutenants, made unwise public statements deriding the 'foamologists'; and even Ron Dittemore, Nasa's technically expert shuttle-programme manager, joined in with categorical denials.
At the CAIB, Gehman, who was not unsympathetic to Nasa, watched these reactions with growing scepticism and a sense of déjà vu. Over his years in the Navy, and as a result of the Cole inquiry, he had become something of a student of large organisations under stress. To me he said, 'It has been scorched into my mind that bureaucracies will do anything to defend themselves. It's not evil - it's just a natural reaction of bureaucracies, and since Nasa is a bureaucracy, I expect the same out of them. As we go through the investigation, I've been looking for signs where the system is trying to defend itself.' Of those signs the most obvious was this display of blind faith by an organisation dependent on its engineering cool; Nasa, in its absolute certainty, was unintentionally signaling the very problem that it had. Gehman had seen such certainty proved wrong too many times, and he told me he was not about to get 'rolled by the system' as he had been rolled before. 'Now when I hear Nasa telling me things like "Gotta be true!" or "We know this to be true", all my alarm bells go off... Without hurting anybody's feelings, or squashing people's egos, we're having to say, "We're sorry, but we're not accepting that answer."'
That was the form that the physical investigation took on, with hundreds of Nasa engineers and technicians doing most of the detailed work, and the CAIB watching closely and increasingly stepping in. Despite what Gehman said, it was inevitable that feelings got hurt and egos squashed - and indeed that serious damage to people's lives and careers was inflicted. At the Nasa facilities dedicated to shuttle operations (Alabama for rockets, Florida for launch and landing, Texas for management and mission control) the CAIB investigators were seen as invaders of sorts, unwelcome strangers arriving to pass judgment on people's good-faith efforts. On the ground level, where the detailed analysis was being done, there was active resistance, with some Nasa engineers openly refusing to cooperate, or to allow access to records and technical documents that had not been pre-approved for release. Gehman had to intervene. One of the toughest and most experienced of the CAIB investigators later told me he had a gut sense that Nasa continued to hide relevant information, and that it does so to this day. But cooperation between the two groups improved as friendships were made, and the intellectual challenges posed by the inquiry began to predominate over fears about what had happened or what might follow. It was on an informal basis that information flowed best, and that much of the truth was discovered.
Board member Steven Wallace described the investigation not as a linear path but as a picture that gradually filled in. Or as a jigsaw puzzle. The search for debris began the first day, and soon swelled to include more than 25,000 people, at a cost of well over $300m. Nasa received 1,459 debris reports, including some from nearly every state, and also from Canada, Jamaica and the Bahamas. Discounting the geographic extremes, there was still a lot to follow up on. Though the amateur videos showed pieces separating from the shuttle along the entire path over the United States, and though search parties backtracked all the way to the Pacific coast in the hope of finding evidence of the breakup's triggering mechanism, the westernmost piece found on the ground was a left-wing tile that landed near a town called Littlefield, in the Texas Panhandle. Not surprisingly, the bulk of the wreckage lay under the main breakup, from south of Dallas eastward across the rugged, snake-infested brushland of East Texas and into Louisiana; and that is where most of the search took place. The best work was done on foot, by tough and dedicated crews who walked in tight lines across several thousand square miles. Their effort became something of a close sampling of the American landscape, turning up all sorts of odds and ends, including a few apparent murder victims, plenty of junked cars, and clandestine meth labs. More to the point, it also turned up crew remains and more than 84,000 pieces of Columbia, which, at 84,900lb, accounted for 38 per cent of the vehicle's dry weight. Certain pieces that had splashed into the murky waters of lakes and reservoirs were never found. It was presumed that most if not all the remaining pieces had been vapourised by the heat of re-entry, either before or after the breakup.
Some of the shuttle's contents survived intact. For instance, a vacuum cleaner still worked, as did some computers and printers and a Medtronic Tono-Pen, used to measure ocular pressure.
A group of worms from one science experiment not only survived but continued to multiply. Most of the debris, however, was a twisted mess. The recovered pieces were meticulously plotted and tagged, and transported to a hangar at the Kennedy Space Center, where the wing remnants were laid out in correct position on the floor, and what had been found of the left wing's reinforced carbon-carbon (RCC) leading edge was reconstructed in a transparent Plexiglas mold - though with large gaps where pieces were missing. The hangar was a quiet, poignant, intensely focused place, with many of the same Nasa technicians who had prepared Columbia for flight now involved in the sad task of handling its ruins. The assembly and analysis went on through the spring.
One of the principal CAIB agents there was an affable Air Force pilot named Patrick Goodman, an experienced accident investigator who had made both friends and enemies at Nasa for the directness of his approach. When I first met him, outside the hangar, he explained some of the details that I had just seen inside - heat-eroded tiles, burnt skin and structure, and aluminum slag that had emerged in molten form from inside the left wing and had been deposited on to the aft rocket pods. The evidence was complicated because it resulted from combinations of heat, physical forces and wildly varying airflows that had occurred before, during and after the main-body breakup, but for Goodman it was beginning to read like a map. He had faith. He said, 'We know what we have on the ground. It's the truth. The debris is the truth, if we can only figure out what it's saying. It's not a theoretical model. It exists.' Equally important was the debris that did not exist, most significantly large parts of the left wing, including the lower part of a section of the RCC leading edge, a point known as Panel Eight, which was approximately where the launch cameras showed that the foam had hit. Goodman said, 'We look at what we don't have. What we do have. What's on what we have. We start from there, and try to work backwards up the timeline, always trying to see the previous significant event.' He called this 'looking uphill'. It was like a movie run in reverse, with the found pieces springing off the ground and flying upward to a point of reassembly above Dallas, and then Columbia, looking nearly whole, flying tail-first toward California, picking up the Littlefield tile as it goes, and then higher again, through entry interface over the Pacific, through orbits flown in reverse, inverted but nose first, and then back down toward earth, picking up the external tank and the solid rocket boosters during the descent, and settling tail-first with rockets roaring, until just before a vertical touchdown a spray of pulverised foam appears below, pulls together at the left-wing leading edge, and rises to lodge itself firmly on the side of the external tank.
The foam did it.
There was plenty of other evidence, too. After the accident the Air Force dug up routine radar surveillance tapes that upon close inspection showed a small object floating alongside Columbia on the second day of its mission. The object slowly drifted away and disappeared from view. Testing of radar profiles and ballistic coefficients for a multitude of objects found a match for only one: a fragment of RCC panel of at least 140 sq in. The match never quite passed muster as proof, but investigators presumed that the object was a piece of the leading edge, that it had been shoved into the inside of the wing by the impact of the foam, and that during manoeuvring in orbit it had floated free. The picture by now was rapidly filling in.
But the best evidence was numerical. It so happened that because Columbia was the first of the operational shuttles, it was equipped with hundreds of additional engineering sensors that fed into an onboard data-collection device, a box known as a modular auxiliary data system, or Mads recorder, that was normally used for postflight analysis of the vehicle's performance. During the initial debris search this box was not found, but such was its potential importance that after careful calculation of its likely ballistic path, another search was mounted, and on 19 March it was discovered - lying in full view on ground that had been gone over before. The really surprising thing was its condition. Though the recorder was not designed to be crashproof, and used Mylar tape that was vulnerable to heat, it had survived the breakup and fall completely intact, as had the data that it contained, the most interesting of which pertained to heat rises and sequential sensor failures inside the left wing. When combined with the telemetric data that already existed, and with calculations of the size and location of the sort of hole that might have been punched through the leading edge by the foam, the new data allowed for a good fit with computational models of the theoretical airflow and heat propagation inside the left wing, and it steered the investigation to an inevitable conclusion that the breach must have been in the RCC at Panel Eight.
By early summer the picture was clear. Though strictly speaking the case was circumstantial, the evidence against the foam was so persuasive that there remained no reasonable doubt about the physical cause of the accident. As a result, Gehman gave serious consideration to Nasa's request to call off a planned test of the launch incident, during which a piece of foam would be carefully fired at a fully rigged RCC Panel Eight. Nasa's argument against the test had some merit: the leading-edge panels (44 per shuttle) are custom-made, $700,000 components, each one different, and the testing would require the use of the last spare Panel Eight in the entire fleet. Nasa said that it couldn't afford the waste, and Gehman was inclined to agree, precisely because he felt that breaking the panel would prove nothing that hadn't already been amply proved. By a twist of fate it was the sole Nasa member of the CAIB, the quiet, cerebral, earnestly scientific Scott Hubbard, who insisted that the test proceed. Hubbard was one of the original seven board members. At the time of the accident he had just become the director of Nasa's Ames Research Center, in California. Months later now, in the wake of Gehman's rebellion, and with the CAIB aggressively moving beyond the physical causes and into the organisational ones, he found himself in the tricky position of collaborating with a group that many of his own people at Nasa saw as the enemy. Hubbard, however, had an almost childlike belief in doing the right thing, and having been given this unfortunate job, he was determined to see it through correctly. Owing to the closeness of his ties to Nasa, he understood something that others might have overlooked: despite the overwhelming evidence, many people at Nasa stubbornly believed that the foam strike on launch could not have caused Columbia's destruction. Hubbard argued that if Nasa was to have any chance of self-reform, these people would have to be confronted with reality, in the most tangible way possible. Gehman found the argument convincing, and so the foam shot proceeded.
The work was done in San Antonio, using a compressed-nitrogen gun with a 35ft barrel, normally used to fire dead chickens - real and artificial - against aircraft structures in bird-strike certification tests. Nasa approached the test kicking and screaming all the way, insisting, for instance, that the shot be used primarily to validate an earlier debris-strike model (the so-called Crater model of strikes against the underside tiles) that had been used for decision-making during the flight, and was now known to be irrelevant. Indeed, it was because of Nasa obstructionism - specifically the illogical insistence by Nasa rocket engineers that the chunk of foam that had hit the wing was significantly smaller (and therefore lighter) than the video and film record showed it to be - that the CAIB and Scott Hubbard finally took direct control of the testing. There was in fact a series of foam shots, increasingly realistic according to the evolving analysis of the actual strike, that raised the stakes from a glancing blow against the underside tiles to steeper-angle hits directly against leading-edge panels. The second-to-last shot was a 22-degree hit against the bottom of Panel Six: it produced some cracks and other damage deemed too small to explain the shuttle's loss. Afterward there was some smugness at Nasa, and even Sean O'Keefe, who again was badly advised, weighed in on the matter, belittling the damage. But the shot against Panel Six was not yet the real thing. That was saved for the precious Panel Eight, in a test that was painstakingly designed to duplicate (conservatively) the actual impact against Columbia's left wing, assuming a rotational 'clocking angle' 30 degrees off vertical for the piece of foam. Among the engineers who gathered to watch were many of those still living in denial. The gun fired, and the foam hit the panel at a 25-degree relative angle at about 500mph. Immediately afterward an audible gasp went through the crowd. The foam had knocked a hole in the RCC large enough to allow people to put their heads through. Hubbard told me that some of the Nasa people were close to tears. Gehman had stayed away in order to avoid the appearance of gloating. He could not keep the satisfaction out of his voice, however, when later he said to me: 'Their whole house of cards came falling down.'
As the report was released, on 26 August, Mars came closer to earth than it had in 60,000 years. Gehman told me that he continued to believe in the importance of America's human space-flight effort, and even of the return of the shuttle to flight - at least until a replacement with a clearer mission can be built and put into service. It was a quiet day in Washington, with Congress in recess and the President on vacation. Aides were coming from Capitol Hill to pick up several hundred copies of the report and begin planning hearings for the fall. The White House was receiving the report too, though keeping a cautious distance, as had been expected; it was said that the President might read an executive summary. Down in Houston, board members were handing copies to the astronauts, the managers, and the families of the dead.
Gehman was dressed in a suit, as he had been at the start of all this, seven months before. It was up to him now to drive over to Nasa headquarters, in the southwest corner of the city, and deliver the report personally to Sean O'Keefe. I went along for the ride, as did the board member Sheila Widnall, who was there to lend Gehman some moral support. The car was driven by a Navy officer in whites. At no point since the accident had anyone at Nasa stepped forward to accept personal responsibility for contributing to this accident. However, the report in Gehman's hands (248 pages, full colour, well bound) made responsibility very clear. This was not going to be a social visit.
Indeed, it turned out to be extraordinarily tense. Gehman and Widnall strode up the carpeted hallways in a phalanx of anxious, dark-suited Nasa staffers, who swung open the doors in advance and followed close on their heels. O'Keefe's office suite was practically imperial in its expense and splendour. High officials stood in small, nervous groups, murmuring. After a short delay O'Keefe appeared - a tall, balding, gray-haired man with stooped shoulders. He shook hands and ushered Gehman and Widnall into his inner office. Ten minutes later they emerged. There was a short ceremony for Nasa cameras, during which O'Keefe thanked Gehman for his important contribution, and then it was time to leave. As we drove away, I asked Gehman how it had been in there with O'Keefe.
He said 'Stiff. Very stiff.'
We talked about the future. The report had made a series of recommendations for getting the shuttle back into flight, and beyond that for beginning Nasa's long and necessary process of reform. I knew that Gehman, along with much of the board, had volunteered to Congress to return in a year, to peer in deeply again, and to try to judge if progress had been made. I asked him how genuine he thought such progress could be, and he managed somehow to express hope, though sceptically.
The blessing, if one can be found, is that the astronauts remained unaware until nearly the end.
A home video shot on board and found in the wreckage documented the relaxed mood in the cockpit as the shuttle descended through the entry interface at 400,000ft, at 7:44:09 Houston time, northwest of Hawaii. The astronauts were drinking water in anticipation of gravity's redistributive effect on their bodies. Columbia was flying at the standard 40-degree nose-up angle, with its wings level, and still doing nearly 17,000mph; outside, though the air was ultra-thin and dynamic pressures were very low, the aerodynamic surfaces were beginning to move in conjunction with the array of control jets, which were doing the main work of maintaining the shuttle's attitude, and would throughout the re-entry. The astronauts commented like sightseers as sheets of fiery plasma began to pass by the windows.
The pilot, McCool, said, 'Do you see it over my shoulder now, Laurel?'
Sitting behind him, the mission specialist Laurel Clark said, 'I was filming. It doesn't show up nearly as much as the back.'
McCool said to the Israeli payload specialist, Ilan Ramon, 'It's going pretty good now. Ilan, it's really neat - it's a bright orange-yellow out over the nose, all around the nose.'
The commander, Husband, said, 'Wait until you start seeing the swirl patterns out your left or right windows.'
McCool said, 'Wow.'
Husband said, 'Looks like a blast furnace.'
A few seconds later they began to feel gravity. Husband said, 'Let's see here... look at that.'
McCool answered, 'Yup, we're getting some Gs.' As if it were unusual, he said, 'I let go of the card, and it falls.' Their instruments showed that they were experiencing 100th of a G. McCool looked out the window again. He said, 'This is amazing. It's really getting, uh, fairly bright out there.'
Husband said, 'Yup. Yeah, you definitely don't want to be outside now.'
The flight engineer, Kalpana Chawla, answered sardonically, 'What - like we did before?' The crew laughed.
Outside, the situation was worse than they imagined. Normally, as a shuttle streaks through the upper atmosphere it heats the air immediately around it to temperatures as high as 10,000 degrees centigrade, but largely because of the boundary layer - a sort of air cushion created by the leading edges - the actual surface temperatures are significantly lower, generally around 3,000 degrees centigrade, which the vehicle is designed to withstand, if barely. The hole in Columbia's leading edge, however, had locally undermined the boundary layer, and was now letting in a plume of superheated air that was cutting through insulation and working its way toward the inner recesses of the left wing. It is estimated that the plume may have been as hot as 8,000 degrees centigrade near the RCC breach. The aluminum support structures inside the wing had a melting point of 1,200 degrees centigrade, and they began to burn and give way.
The details of the left wing's failure are complex and technical, but the essentials are not difficult to understand. The wing was attacked by a snaking plume of hot gas, and eaten up from the inside. The consumption began when the shuttle was over the Pacific, and it grew worse over the United States. It included wire bundles leading from the sensors, which caused the data going into the Mads recorder and the telemetry going to Houston to fail in ways that only later made sense.
At some point the plume blew right through the top of the left wing, and began to throw molten metal from the insides all over the aft rocket pods. At some point it burned its way into the left main gear well, but it did not explode the tyres.
As drag increased on the left wing, the autopilot and combined flight-control systems at first easily compensated for the resulting tendency to roll and yaw to the left. By external appearance, therefore, the shuttle was doing its normal thing, banking first to the right and then to the left for the scheduled energy-management turns, and tracking perfectly down the descent profile for Florida. The speeds were good, the altitudes were good, and all systems were functioning correctly. From within the cockpit the ride appeared to be right.
By the time it got to Texas Columbia had already proved itself a heroic flying machine, having endured for so long at hypersonic speeds with little left of the midsection inside its left wing, and the plume of hot gas still in there, alive, and eating it away. By now, however, the flight-control systems were nearing their limits. The breakup was associated with that. At 7:59:15 Mission Control noticed the sudden loss of tyre pressure on the left gear as the damage rapidly progressed. This was followed by Houston's call 'And Columbia, Houston, we see your tyre-pressure messages, and we did not copy your last call', and at 7:59:32 by Columbia's final transmission, 'Roger, ah, buh...'
Columbia was travelling at 12,738mph, at 200,000ft, and the dynamic pressures were building, with the wings 'feeling' the air at about 170mph. Now, suddenly, the bottom surface of the left wing began to cave upward into the interior void of melted and burnt-through bracing and structure. As the curvature of the wing changed, the lift increased, causing Columbia to want to roll violently to the right; at the same time, because of an increase in asymmetrical drag, it yawed violently to the left. The control systems went to their limits to maintain order, and all four right yaw jets on the tail fired simultaneously, but to no avail.
At 8:00:19 Columbia rolled over the top and went out of control.
The gyrations it followed were complex combinations of roll, yaw, and pitch, and looked something like an oscillating flat spin. They seem to have resulted in the vehicle's flying backwards. At one point the autopilot appears to have been switched off and then switched on again, as if Husband, an experienced test pilot, was trying to sort things out. The breakup lasted more than a minute. Not surprisingly, the left wing separated first. Afterward the tail, the right wing, and the main body came apart in what investigators later called a controlled sequence 'right down the track'. As had happened with the Challenger in 1986, the crew cabin broke off intact. It assumed a stable flying position, apparently nose high, and later disintegrated like a falling star across the East Texas sky.
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