Challenger: A True Story of Heroism and Disaster on the Edge of Space

by Adam Higginbotham

When asked what he was thinking about when preparing for launch aboard his Mercury-Redstone rocket, Alan Shepard, the first American in space, had infamously replied, “The fact that every part of this ship was built by the low bidder.”

The NASA managers and astronauts alike were in the grip of what they would later recognize as “ ‘Go’ Fever”—the desperate drive to push on toward a launch and keep to the schedule, regardless of the problems, in the belief that if they just kept going they could fix all the faults along the way.

The buildings from which the Apollo astronauts and their spacecraft would prepare to leave on the lunar voyage—the Operations and Checkout Building, with its crew dormitory and suiting-up room; the Vehicle Assembly Building in which the Saturn rockets would be stacked together; and the angular, modernist Launch Control Center in its shadow—had been constructed amid eighty-eight thousand acres of mosquito-infested wetland and alligator-filled lagoons.

But nature had surrendered only reluctantly to the advance of the Space Age: it took the Army Corps of Engineers three years and stupendous quantities of insecticide to render the area “biologically unfit” for the mosquito; the foundations of the monumental Vehicle Assembly Building, which was large enough to contain the Great Pyramid of Cheops, were anchored by thousands of steel tubes driven into bedrock 160 feet beneath the surface of the island, to stabilize the boxlike structure in high winds. And the subtropical weather could be unpredictable, bringing violent thunderstorms in the summer, occasional hurricanes, and banks of fog that shut down launchpads and runways with little warning in the winter.

The theoretical recognition that things could possibly go wrong was supplanted by the cold realization that they would. Those with backgrounds in the missile industry and in systems engineering were hit especially hard by the disaster—they were the ones who had believed that all risks could be removed from spaceflight; accidents should never happen. Those who came from the world of flight testing, like the majority of the astronauts themselves, found it easier to move on after the accident. These men recognized the realities of the work they were doing, and were prepared to live with the consequences.

By decade’s end, the extraordinary success of the project had been matched only by its exorbitant cost: at its peak, NASA had some four hundred thousand men and women at work on Apollo, and the price of the program’s support facilities alone was $2.2 billion; the technology and materials of the lunar lander were so exotic that each one cost fifteen times its weight in gold. In total the project would cost the country an astonishing $28 billion—the equivalent to a third of all US military spending for 1969, at the height of the Vietnam War.

The scope of exploration, and distances, involved in the vehicles’ respective journeys were scarcely comparable: Armstrong and Aldrin’s trip to the lunar surface required them to break entirely free of Earth’s gravity and embark on an eight-day round trip through more than 900,000 miles of outer space; the Space Shuttle would be required merely to travel into low Earth orbit—between 190 and 330 miles above sea level—where it would circle the planet for up to a week before returning home.

Intended to blast off like a rocket, go into orbit like a spacecraft, and land like an airplane, almost every element of the proposed new ship would have to survive the full range of the extraordinary forces exerted on man and machine by spaceflight. These would begin with liftoff, where the acoustic shock of its rocket engines screaming in unison could reach 167 decibels—powerful enough to kill a human being. As it ascended and accelerated, the shuttle would be buffeted by wind resistance and drag equivalent to several times its weight on the ground, until it reached the point known by the engineers as “Max Q”—the point at which the airframe risks being torn to pieces by the forces of maximum aerodynamic stress. On reaching the vacuum of space, it would be plunged into temperatures of minus 250 degrees Fahrenheit—the “cold soak,” low enough to embrittle metal to the point that it can shatter like hard candy. On reentry, the skin of the craft, enveloped by ionizing air and blazing plasma, would heat from cold soak to 2,700 degrees Fahrenheit—high enough to melt steel—and reach a velocity of up to twenty-five times the speed of sound before slowing to a few hundred miles an hour to land on its own undercarriage under the control of its pilots.

After the war, both von Braun and Dornberger were among the 120 German rocket engineers brought to the United States as part of Operation Paperclip, a secret US government scheme to exploit the Nazis’ scientific expertise in the emerging confrontation with the Soviet Union.

They feared the potential effects of weightlessness on spacecraft components and on the bodies of pilots; in the absence of aerodynamic data about reentry, they were concerned about how they might maintain control of a vehicle traveling at more than five times the speed of sound—the still largely unexplored realm of hypersonic flight—and the integrity of its structure as it encountered temperatures that they believed could reach as high as 4,500 degrees Fahrenheit.

In 1958, NASA had been established by the National Aeronautics and Space Act, which stated that “it is the policy of the United States that activities in space should be devoted to peaceful purposes for the benefit of all mankind.”

In a pair of flights in the summer of 1963, veteran test pilot Joe Walker took the X-15 beyond 330,000 feet, over the internationally recognized boundary of space—the Karman Line, sixty-two miles up—unofficially becoming the first man in history to travel into space twice. But almost from the beginning, the X-15 pilots’ exploits were eclipsed by the glamour and pyrotechnics of the Mercury and Gemini spacecraft. While John Glenn and Alan Shepard were celebrated with ticker-tape parades and appeared on the covers of Life, few people outside the aerospace industry knew or cared about the X-15 or those who flew it. Yet the lack of attention had its benefits: ignored by the media, NASA’s high desert rocket plane experiments proceeded with little oversight or interference from politicians or bureaucrats in Washington, DC.

NASA soon began using the three X-15s as platforms for scientific experiments, mounting equipment in wingtip pods that the pilots opened in the upper reaches of the atmosphere, to gather data on esoteric high-altitude phenomena. Their exploration expanded knowledge of both aerospace engineering and medicine: flight surgeons discovered that the pilots’ heart rates during X-15 flights were more than double those recorded on tests of other aircraft, due to the seemingly inexorably rising strain they felt while confined in their cockpits, anticipating each launch. The pressure suits they wore provided the basis for those used to outfit the Mercury astronauts. But testing the limits of existing technology in such an unforgiving environment was fraught with risk, and the pilots’ experimental role often required them to push their aircraft far into the unknown. In an aircraft traveling at more than a mile a second, the smallest mechanical fault—or the tiniest miscalculation—could escalate at bewildering speed.

Although the simulations often created circumstances in which the shuttle crews’ missteps or miscalculations might result in a crash, the supervisors never devised scenarios from which they knew there was no escape, or would inevitably end in what NASA engineers referred to as “loss of vehicle, mission and crew”: certain death.

With no control and no means of escape, this made the first 122 seconds of flight the most dangerous part of any mission aboard the shuttle.

Among them was a framed copy of “High Flight,” the poem written by Royal Canadian Air Force pilot John Gillespie Magee, Jr. a few months before his death in a midair collision over England in 1941. First made famous during World War II, Magee’s sonnet would become a favorite of US military pilots and, later, of astronauts: Michael Collins had carried a copy on his first journey into space, aboard Gemini X, fourteen lines of verse typed onto a small file card by his wife, Pat:

Oh! I have slipped the surly bonds of Earth And danced the skies on laughter-silvered wings; Sunward I’ve climbed, and joined the tumbling mirth Of sun-split clouds,—and done a hundred things You have not dreamed of—wheeled and soared and swung High in the sunlit silence. Hov’ring there, I’ve chased the shouting wind along, and flung My eager craft through footless halls of air.… Up, up the long, delirious, burning blue I’ve topped the wind-swept heights with easy grace Where never lark nor ever eagle flew— And, while with silent lifting mind I’ve trod The high untrespassed sanctity of space, Put out my hand, and touched the face of God.

Down at the Cape, Al McDonald was making a final attempt to persuade Mulloy to change course, itemizing three separate reasons to cancel the launch: not just the O-ring problem; but the Atlantic storms that had overtaken the recovery ships, jeopardizing the retrieval of the boosters; and the possibility that ice formed on the launch gantry would damage the orbiter as it took off. But the NASA managers brushed him off. They told him only that they would pass along his concerns to those whose job it was to worry about them.

McDonald insisted that he believed that by going ahead they were contravening their own flight qualification rules: “If anything happens,” he said, “I wouldn’t want to be the person that has to stand in front of a board of inquiry to explain why we launched…”

But neither Reinartz nor Mulloy told Aldrich of Thiokol’s concern about the O-rings—and Cecil Houston sensed that they didn’t want him to, either. So he stood and listened in silence. The call concluded with an agreement to resume the countdown: Challenger would launch at 9:38 a.m. the next day.

Al McDonald handed over the single sheet of paper testifying to Morton Thiokol’s approval for the mission and waited while the men from Marshall read it.

Out on the pad, temperatures had reached their lowest shortly after dawn, falling to 24 degrees Fahrenheit—eight degrees below freezing. The seething cold had crept into everything: the doors on the gantry elevator had become sluggish; several of the remote cameras had stopped working; an oxygen sensor aboard the shuttle had failed; one radio channel had been knocked out; and, down on the Mobile Launcher Platform, beneath the nozzles of the solid rockets—and in defiance of the hundreds of gallons of antifreeze—water in the sound suppression troughs had frozen solid. Sheer cascades of ice now descended from near the very top of the launch tower, bearding the walkways just sixty feet from Challenger’s left wingtip and encapsulating communications equipment. “Looks like, uh, something out of Dr. Zhivago,” said the Rockwell liaison, surveying the closed-circuit TV images from the Launch Control Center; he had never seen anything like it. “There’s sheets of icicles hanging everywhere,” he said.

As they took temperature readings around the shuttle with a handheld infrared thermometer, the instrument produced odd results: the surface of the left-hand solid rocket booster registered at around 25 degrees Fahrenheit, close to the air temperature at sunrise. But at the bottom of the right-hand booster, near the aft field joint, the reading was just 8 degrees—an astonishing 24 degrees below freezing; that just couldn’t be right. Stevenson and his engineers assumed the thermometer was malfunctioning, and took note of the numbers, but kept the data to themselves.

Petrone ran the West Coast contractor’s shuttle operations with an iron hand—and had left the Cape in disgust the previous afternoon, after witnessing the bolt fiasco unfold on Pad 39B. Now, watching the closed-circuit TV images of the icicles festooning the gantry and equipment around Challenger from the plant in Downey, he told his managers to make it clear to NASA that Rockwell could not approve the launch. “It is not safe,” he said.

First, Aldrich heard the analysis from a team of NASA engineers: based on their calculations of wind speed, fragmentation, and debris trajectory, they felt good about the ice; it was unlikely to cause significant damage. They gave their go-ahead for launch, as soon as the air temperature rose above 31 degrees Fahrenheit. But when he turned to Rocco Petrone’s men, they passed on the message from their boss: the situation was unpredictable, and unlike anything they’d seen before, said one. The other was more direct. “Rockwell cannot assure that it is safe to fly,” he said.

And yet Aldrich had made up his mind: his own engineers were unanimous; a single dissenting voice—even from the contractors who had built the orbiter—was not enough to stop the launch.

On the fourth floor of the Launch Control Center, a NASA official began leading the wives and children out of Thomas’s office, down the hallway, past rows of cubicles, and out through a heavy self-closing door. One by one, they stepped out on to the roof and mounted the big steel staircase to the very top of the building: a broad expanse of pale concrete the size of a football field, surrounded by a white railing that cast a crisp shadow in the winter sunshine.

But in the bottom-most field joint of the right-hand booster rocket, the cold had done its work: the synthetic rubber of the seals and the thick grease they were packed in had proved too inflexible to close the gap that opened in the case at ignition. Hot gas at more than 5,000 degrees Fahrenheit had blasted past the primary seal—and then broken through the second seal, too, instantly vaporizing portions of the O-rings as it went. Unseen by the crowd or the officials in the Launch Control Center, burning grease, insulation, and Viton rubber spurted from the ruptured joint in puffs of coal-black smoke.

Burning at more than 6,000 degrees, in less than three seconds the errant flame escaping from the booster encircled the circumference of the giant external tank, incinerated its insulation, cut through its aluminum skin, and ruptured the welds of the pressurized fuel tank membrane within. A plume of liquid hydrogen burst into the slipstream of the rocket engines, where it ignited.

At seventy-two seconds, the tank lost its structural integrity and tore apart, crumpling and disgorging the remaining liquid hydrogen—more than 300,000 gallons of it—which bloomed into a colossal fireball. Released from its aft anchors, the right-hand booster swiveled around its upper attachment point. Its nose smashed into the right wing of Challenger, and the liquid oxygen tank, tearing it open.

The orbiter was engulfed in a swelling cloud of combustible propellant, and the nozzles of its three main engines swiveled wildly as the onboard computers struggled to regain control of the disintegrating spacecraft; for the few fractions of a second it took for the engines to consume the fuel remaining in the feed lines, their high-pressure turbopumps continued to spin, until the computers shut them down one at a time. Then the booster rockets tore free from their mounts, and Challenger, still hurtling toward space at almost 1,500 miles per hour, tumbled from its precisely prescribed supersonic trajectory. Its airframe stressed far beyond its design limits, the most complicated machine in history began to come apart in flight: its stubby wings ripped away, the cargo bay bursting like a paper bag, the inrushing air pulling the fuselage asunder from the inside.

A heavy silence filled the room; beside Thomas in the top tier, the other senior managers sat stupefied. Some buried their heads in their hands. Others began to weep. “It’s a bad day,” murmured the Shuttle Operations Director, Bob Sieck. Like everyone else, George Abbey was poleaxed with shock. And then he thought of the families on the roof. First, he picked up the phone, calling drivers to take the relatives to crew quarters, away from the eyes of the press.

A voice said, “That’s not right. That’s not right.” Another: “That’s not right at all.”

“We have a report from the Flight Dynamics Officer that the vehicle has exploded,” he said, and his voice cracked. “The Flight Director confirms that. We are looking at—uh—checking with the recovery forces to see what can be done at this point.…”

“OK,” he said. “Lock the doors.”

“Stop crying,” one of the other women told Alison. “You’re upsetting everyone.”

It was an hour before George Abbey gathered the adults in the conference room and confirmed what many of them already knew.

Alison began hyperventilating. The flight surgeon brought her a paper bag.

Whether gathered in classrooms, at home or at work, or transfixed by the images flickering across rows of TV screens in store windows, as midnight arrived on Tuesday an estimated 95 percent of American adults had seen the footage of the shuttle’s final moments. And many felt the loss of the seven astronauts as a shattering blow—a national bereavement unlike any event since the assassination of John Kennedy more than twenty years before.

Within twenty-four hours, the film from the 70-millimeter high-speed movie cameras—equipped with telescopic lenses, shooting forty frames a second, from angles not shown on TV—that had tracked the launch from Cape Canaveral had been processed and copies flown up to Houston from Florida. Spooling the footage across a light box, one frame at a time, the astronauts analyzing the images in the Space Center lab could see a tongue of bright flame flaring from the aft joint in the right-hand solid rocket booster about sixty seconds after launch. As soon as they saw it, they knew exactly what had happened.

When he saw the film from the high-speed cameras on Wednesday evening, it confirmed his worst fears: that the accident had been caused by one of the Morton Thiokol boosters; worse still, it might have been caused by the very thing that McDonald had tried to warn NASA about the evening before the launch.

Still, NASA—insisting that its engineers would have to work systematically through an exhaustive fault tree diagnosis before reaching conclusions of any kind about the causes of the accident—chose not to release any of this information to the press.

But now the agency’s reticence and apparent stonewalling about what it knew began to backfire. Veteran reporters on the space beat, accustomed to the agency’s traditions of apparent transparency and reliant on their convivial relationship with its public affairs officers, now found themselves cut off from their chief sources of information and denied answers to questions about even the most basic facts surrounding the accident.

With a view of Challenger’s right-hand solid rocket at the moment of ignition, this camera had captured a decisive piece of evidence: just over six-tenths of a second after the boosters had lit, McDonald could see a series of eight puffs of black smoke escape from near the aft field joint in the rocket. Looking more closely, it was clear to him that each puff blew upward toward the nose of the rocket, just as it would if it was being directed out of the joint by the clevis, following a failure of the O-rings at ignition. McDonald no longer had any doubt: his boosters had killed the astronauts, after all.

On Saturday, the New York Times quoted another anonymous source, who described the drop in pressure inside the right-hand booster a minute into flight, and said that NASA now believed the accident had been caused by a flame leaking from the rocket and burning a hole in the shuttle’s external fuel tank. Even so, the agency wasn’t ready to say anything publicly—perhaps, the paper suggested, because it feared who would be blamed for what happened. Asked that day if there had ever been a leak between the segments of a solid rocket booster, Jesse Moore said that no such fault had ever appeared in any one of nine static tests or twenty-four previous shuttle flights. “In 57 uses, there has never been a leak, not a single one. That’s not an opinion, it’s just a straight fact.”

On Monday, February 3, the President made the formal announcement that he was stripping NASA of the authority to continue investigating itself. Instead, he had appointed William Rogers—a Republican loyalist, Washington insider, and former Attorney General who had served as Secretary of State under Nixon—as the head of the independent Presidential Commission on the Space Shuttle Challenger Accident. “It’s time now to assemble a group of distinguished Americans to take a hard look at the accident,” Reagan said, “to make a calm and deliberate assessment of the facts and ways to avoid repetition.”

But that weekend, the inquiry took an abrupt turn. On Sunday morning, the New York Times carried a shocking front-page splash: “NASA Had Warning of a Disaster Risk Posed by Booster.” The story, based on internal memos leaked to the paper by a budget analyst at the space agency’s headquarters, revealed the long history of damage to the seals stretching back to 1981, and quoted from internal documents citing the risks of O-ring failure: “loss of vehicle, mission and crew due to metal erosion, burn-through and probable case burst resulting in fire and deflagration.”

The story described how copies of the memos had been sent to Jesse Moore, and how the seal damage they documented seemed clearly to contradict what Judson Lovingood had told the commission under oath only a few days before. And all of it was news to William Rogers and the other members of the commission.

Richard Feynman made clear that Mason’s decision to overturn his engineers’ advice to postpone the flight had no empirical foundation; it had, instead, been a reckless gamble.

That afternoon, Roger Boisjoly took his turn before the panel, and testified to his long months of attempts to fix the O-ring problems. He read aloud from his “smoking gun” memos, and recalled how, in the climactic teleconference, the Marshall engineers had said that they were “appalled” at his recommendation not to launch.