Compromised Ambitions: Lessons of the Shuttle Disasters
Thirty-five years ago today, America lost astronauts for the first time during a mission. The Space Shuttle Challenger, STS-51-L, lifted off on an unusually cold Florida morning. She shouldn’t have. Seventy-three seconds later, Challenger broke apart. All seven of her crew, including New Hampshire social studies teacher Christa McAuliffe, were lost. The anniversary marks an opportunity to look at the Shuttle’s extraordinary origin story, the ambitions that fueled it, the political and design compromises made along the way and the loss of both Challenger and her sister, Columbia. As the United States rebuilds a human spaceflight program, the lessons of these failures and the political compromises that drove them must be carefully re-learned.
Different causes, different politics, same results
After this first Shuttle disaster, the investigation by the Rodgers Commission concluded that a rubber gasket in the right solid rocket booster, called an “o-ring”, became brittle in the uncommonly cold conditions and failed. Flames from the point of the failure then ignited the huge external fuel tank, blowing the spacecraft apart as it climbed into the sky.
The destruction of Challenger and Columbia had very different proximate causes under different circumstances — Challenger flew for just over one minute before she broke apart; Columbia disintegrated just minutes from landing after two weeks in space.
In early 2003, Columbia STS-107 flew 6 1/2 million miles and 255 orbits of the Earth in those two weeks, all with a bowling ball-sized hole in her left wing, the product of a collision between the leading edge of the wing and a piece of thermal insulating foam that broke free from Columbia’s external fuel tank 82 seconds into flight on January 16. Foam strikes had occurred on previous Shuttle flights and NASA managers, made aware of the strike by high resolution photography of the launch available the following day, determined there was no cause for concern. Mission Control informed Columbia’s crew about the strike and said it would not affect their mission. But that suitcase-sized bit of foam insulation would not only doom Columbia, it would be the catalyst for retiring the entire Shuttle fleet.
On February 1, as she descended into the Earth’s atmosphere at 15,000 miles per hour, the leading edge of Columbia’s wings heated up to nearly 3,000 degrees Fahrenheit, about a third that of the surface of the Sun. Like all re-entering objects, the Shuttle’s speed created an intense pressure wave at its leading surfaces as it began to encounter friction from the steadily thickening atmosphere. This pressure wave transformed the air in front of her into a blistering hot incandescent plasma, which then flooded into the structure of her wing through the hole created by the foam strike. Columbia disintegrated over the southwestern United States, killing all seven of her crew. Parts of the orbiter were found in three states.
The political environment in which the Columbia Accident Investigation Board (CAIB) operated after this disaster was very different than the one faced by the Rodgers Commission seventeen years earlier. When the Rodgers Commission submitted its report to President Reagan, the Shuttle program was still new. America had bet its entire human spaceflight future on the Shuttle and spent billions to develop it and build out the fleet. It was politically untenable to simply scrap the Shuttle. But by 2003, the CAIB evidently felt it could be bold enough to label the Shuttle a “complex and risky system.” Moreover, in 2003 the International Space Station, which America needed the Shuttle in order to build, was at least well underway if far from complete.
So while the Rogers Commission stopped short of making broad conclusions about the long-term viability of the Shuttle system itself, the CAIB was not so discreet. It issued a withering report on the loss of Columbia. The CAIB rightly found that the Shuttle was a marvel of engineering. But it also concluded that while compromises made in the Shuttle’s design did not themselves make the vehicle fundamentally unsafe for human spaceflight, nonetheless “the increased complexity of a Shuttle designed to be all things to all people created inherently greater risks than if more realistic technical goals had been set at the start. Designing a reusable spacecraft that is also cost-effective is a daunting engineering challenge; doing so on a tightly constrained budget is even more difficult.” Political and budget pressures building in the post-Apollo years helped to create a radical, enormously ambitious vehicle that demanded the development of new technologies without the resources to match. “One of the major problems with the way the Space Shuttle Program was carried out was an a priori fixed ceiling on development costs. That approach should not be repeated,” the CAIB said.
But Challenger was felled by more than a cracked 0-ring and chilly weather; Columbia’s loss was due to more than a bit of foam insulation. Policy makers at the highest levels of government with little enthusiasm for space and a space agency desperate for a worthy successor to Apollo made a series of fateful decisions that would create an even more ambitious, and risky, vehicle than originally envisioned.
Spaceship in search of a mission
From the very moment Commander Neil Armstrong pressed humanity’s first footprints on another world, thus satisfying President Kennedy’s challenge to beat the Soviet Union to our celestial neighbor, America’s efforts in human spaceflight went out of focus. Going into the moon flights, NASA had big plans — ten Apollo landings, then a follow-on space station and a Space Transportation System (the Space Shuttle fleet) to service it, a Grand Tour of the outer solar system using robotic spacecraft and finally a human mission to Mars, all by the 1980s. By the time he became president in January 1969, Richard Nixon inherited a space program nearly ready to bear geopolitical fruit. But Nixon had little of Kennedy’s public zest for space. His public comments were far more cautious and qualified, even as he announced a bold program like the Shuttle. He was keen to internationalize US space efforts which would make them cheaper in terms of money but more costly in terms of time.
In the intervening years, Project Apollo had grown from Kennedy’s stated goal of landing a (one) man on the moon into a plan to land 20, two moonwalkers in 10 flights, culminating with Apollo 20. In the end, the United States made just six landings from 1969 to 1972. The hardware was already in place for all 10 flights, but a failure in the Apollo 13 Service Module en route to the moon aborted that landing and Apollo 18, 19 and 20 were canceled. The reasons are many, but certainly one was that Nixon could read polls as well as anyone. Even during the heady run-up to Apollo 11, polls showed the American public was deeply divided over whether Apollo was a good use of public money. During Project Apollo, America was fighting two wars, one against poverty, the other against North Vietnam. A majority of Americans felt that the money going to the space program could better be spent at home.
A decade earlier, Kennedy acted decisively on his concerns that the US was lagging behind the Soviets in space, and the implications that might have for America’s technological edge. He was also concerned that the perception the US was trailing in space would erode America’s soft power in the global conflict with Soviet Russia. Years later, top US officials grappled with an impression of diminishing American power and prestige even in the immediate afterglow of a triumphant Apollo 11. Nixon had already decided to cancel the final three Apollo flights, but he was now considering cutting the moon program loose after Apollo 15, meaning there would be just four landings. After all, America had beaten the Russians to the moon and technical problems looked as though they would keep the moon free of any red banners. The most significant technical problems were that the Soviet moon vehicles, the giant N-1 rockets, kept exploding. Of the four N-1 test launches, all four failed, some creating the largest non-nuclear explosions in human history. But Caspar Weinberger, then Director of the Office of Management and Budget, wrote in an August 12, 1971 memorandum to President Nixon that he opposed canceling Apollo 16 and 17. “It would be confirming in some respects, a belief that I fear is gaining credence at home and abroad: That our best years are behind us, that we are turning inward, reducing our defense commitments, and voluntarily starting to give up our super-power status.” The president agreed, so the moon missions flew into 1972.
Since the successful Apollo 11 landing had made the moon race politically moot and the spectacular (albeit still secret) failures of their own rockets put the moon beyond Moscow’s grasp, the Soviet Union had shifted its attention to the development of small orbiting laboratories. Thus a “space station gap” was developing that would feed a long-term policy debate about the need for the United States to build a station of its own.
Like Kennedy and Eisenhower before him, Nixon refused to sign off on NASA’s long-term vision but the agency kept on pressing for a space station, knowing that this would be an important milestone on the way to Mars. After Apollo, US space policy made a marked shift from urgent and strong presidential support for ambitious and clearly defined goals to the more complex incremental approach that has characterized it ever since, an approach that is much more in line with how other federal agencies operate. A good example of this can be found in President Nixon’s 1969 request that Vice President Spiro Agnew report to him on recommendations for America’s future space efforts. When President Kennedy had given Lyndon Johnson the same task in 1961, the vice president responded in just eight days. Agnew delivered his report to Nixon in 214 days. It took a further six months for Nixon to respond. Space, it seemed, was sliding down the presidential pecking order. Nonetheless, Agnew’s Space Task Group was hardly modest in its goals. It called for a manned mission to Mars by the end of the 20th Century, though they thought NASA could be ready to make the trip as early as 1986. It also called for a space station and a lunar base.
Since a major space station would be far too large to lift into orbit in one piece, such a project would need to be orbited in modules aboard versions of the huge Saturn V moon rocket, then assembled on orbit — a staggering undertaking. To support the station and provide “airline type operations” to ferry people, supplies and components to and from orbit, a new vehicle was needed. NASA called it the Space Transportation System (STS), but the reusable orbiters which were the major component of STS would become universally known as the Space Shuttles. The Shuttle was revolutionary in many ways. It was the first human-rated spacecraft to use solid-fueled boosters, the first with wings, the first with a heat shield and engines that could be reused, the first to land like a plane, the first reusable vehicle overall, the first to fly with people onboard for the initial test flight and the first crewed spacecraft with no crew emergency escape system.
At the same time NASA’s post-Apollo wrangling with Nixon was going on, widening the Shuttle’s uses while winnowing its budget, Wernher von Braun’s vision of a huge orbiting pinwheel that would rotate in space, using its centrifugal force to create artificial gravity around the outside of the wheel had captured the public imagination in, among other things, Stanley Kubrick’s seminal 1968 film 2001: A Space Odyssey. Unfortunately for NASA and von Braun, it evidently did not capture Nixon’s imagination. He would not approve the space station, but he did approve development of the Shuttle — ironic since the primary mission for the Shuttle would have been supporting the station. Ultimately, Nixon did approve a less ambitious orbiting laboratory called Skylab, created partly from the already-built upper stage of what would have been the Apollo 18 launch vehicle, though the Shuttle was not necessary to build or support SkyLab.
From this point forward, the White House would write NASA no more blank checks. America’s space program would scratch and fight with every other federal agency for funding and support. Nixon budget officials saw little value in human spaceflight at all given the enormous costs, so with the space station off the table as a justification for the Shuttle, NASA began looking for an economic reason to build the Shuttle fleet. When the space agency added up the annual number of US commercial, scientific and military payloads, it reasoned that 50 Shuttle launches every year could lift everything America needed to put on orbit. At that extraordinary launch rate (which the Shuttle never came close to achieving) the economics of the Shuttle might even work. With those rosy projections, Nixon approved the Shuttle in 1972, in part to create jobs in key states during an election year and in part due to a warning from NASA Administrator James Fletcher, who, in a memorandum to the president, said: “For the U.S. not to be in space, while others do have men in space, is unthinkable, and a position which America cannot accept.” Those words, used to justify the birth of the Shuttle, could just as easily have been written in 2011 at its demise. Again, the political calculus was dominant. With Weinberger and Fletcher warning Nixon about the blow to American prestige if the nation were left without a worthy successor to Apollo, the Cold War still played a central role in decisions about America’s future in space.
In the lead up to Apollo, then-NASA Administrator James Webb felt he had strong enough presidential support to offer truly realistic budgets for the moon program, which made cost overruns less likely and a schedule easier to keep. This advantage evaporated for his successors. The budget pressures created by a more incremental and constrained approach would lead to costly, and ultimately tragic compromises in the philosophy and the design of the Space Shuttle. In early 1971, NASA told the Office of Management and Budget (OMB) that it needed $10 billion to develop a fully reusable two-stage spacecraft. OMB said perfect — you can have $5 billion.
So, without a space station as the Shuttle’s raison d’être, and half the funding it really needed to do the job, NASA cast about for new allies to justify the Shuttle and new designs to save money. The Pentagon was an obvious choice to support the project, and thus both civil and military requirements now went into the Shuttle’s design.
Fateful decisions
One of military stipulations for the Shuttle was the ability to launch classified payloads up to 60 feet long and weighing up to 18,200 kilograms, while NASA’s desire to — someday — build a space station dictated the width of the payload bay design. The Pentagon also wanted the Shuttle to be able to take off and return to a West Coast launch site (Vandenberg Air Force Base) after a single polar orbit. But the Earth’s rotation meant that a single polar orbit would not bring the shuttle back directly over its launch site. Therefore, in order to land, the ship would have to glide a longer distance through the atmosphere. That requirement, along with the large cargo bay, led NASA to give the Shuttle a larger delta wing design. This larger surface area demanded a redesigned thermal protection system — one which not only had to be robust and reusable, but comparatively light since it had to cover such a large area. This lighter and more fragile system failed for Columbia.
One design change made to save money was relocating most of the fuel to a large tank on the outside the spacecraft; another was to supplement the liquid-fueled main engines with solid-fueled boosters, which are cheaper to build (but more costly to operate). A failure of the solid booster and external fuel tank doomed Challenger. Debris created by the spray-on foam insulation needed on the external tank was the initial cause of Columbia’s loss.
Learning from these mistakes
None of this is to say that solid boosters, external tanks or a delta wing are inherently dangerous; they aren’t. But all these compromises stood at odds with the profound ambitions piled on the Shuttle. Ultimately, they helped to bring the program to a close years before a successor spacecraft could be fielded. Understanding the politics that drove these decisions for the Shuttle should help us make better ones as that new spacecraft, Orion, continues its development.
In the end, America got the Shuttle design that $5 billion could buy. But it never came close to getting the operational efficiency promised, while the risks of the system turned out to be far greater than policy makers realized. Of the five Shuttles in the fleet, flying 135 missions, two were lost — a 40% vehicle loss rate and a 1.5% flight failure rate. One and a half percent may not sound like a lot, but to draw a very limited comparison for some perspective, commercial airlines typically fly 28,500 flights every day over the United States. At a 1.5% flight failure rate, more than 400 commercial aircraft would be lost in the US every day.
Spaceflight is a dangerous business. One reason it isn’t the “airline type” operation that the Shuttle promised is simple. Aircraft fly hundreds or thousands of test flights before they become operational, and they are far less complex and dangerous than spacecraft. But spaceflight is too expensive for that kind of testing. Shuttle flights ended up costing NASA roughly $1.5 billion each. At that rate, and assuming NASA’s current annual funding, if the space agency had adopted a commercial-aircraft-style test flight regime of, say, 1,000 flights for the Shuttle, it would have cost $1.5 trillion and taken just under 80,000 years to complete — all before the spacecraft ever flew an operational mission.
The best homage we can pay to the crews of Challenger and Columbia is to learn the lessons of their sacrifices well so that our national objectives in space are supported by a coherent policy and sufficient resources.
Originally published in Medium as “Compromised Ambitions: Lessons of the Shuttle Disasters.” Want to stay up to date on topics like this? Subscribe to our newsletter and follow us on LinkedIn. We offer strategic insights on the future of space as well as historical and political forces that have shaped the trajectory of advancements in science and technology. Schedule a time to learn more from our team HERE.