When I decided after my astrophysics degree to turn around and head back through the revolving doors of my university to study medicine, my parents cried. Like many immigrant parents, they’d always dreamed of their son becoming a doctor.
My bank manager was close to tears for different reasons. I was running out of cash. I spent weekends filing slides in a photographic agency, worked shifts as a doorman at the student union, and even had a laughably short and shockingly bad stint as a DJ. None of it quite paid the bills.
But I had a plan: NASA. NASA was a multibillion-dollar agency in the business of launching human beings into space. If they were doing that, then they must need doctors, so they must have pots of cash to fund people like me.
NASA, of course, had billions of dollars, but they were all spent—and then some. They had no grant money, and, even if they had, my British passport wasn’t going to help me get to it. As a federal agency of the United States, NASA is forbidden, under executive order of the president, from employing non-Americans. Most of the replies to my inquiries made that point none too subtly.
I gave up on the idea of getting a grant and decided instead to send dozens of letters asking to spend some time as an intern with a NASA research lab. I’d have to do it for free—but at least I’d get up close to the place that had fascinated me throughout my childhood.
Here, too, I was met with a barricade of polite refusals. Then came the age of the dial-up modem, and I started blizzarding out e-mails. I was lucky. It was a time before people had figured out spam filters. Somewhere, somehow, one of those letters, faxes, or e-mails got me an application form—and unbelievably, that application form won me a place in an aerospace-medicine course at Johnson Space Center in Houston.
—
IF YOU RISE UP THROUGH THE atmosphere from sea level, the going gets tough long before you get anywhere near space. Anything above 5,000 feet counts as “high altitude” as far as physiologists are concerned. Even at this modest height, the medical problems caused by altitude can begin to develop.
Once you get to around 29,000 feet, just five and a half miles above the ground, you reach the highest point on the surface of the planet: the summit of Mount Everest. This appears to be very nearly the high-altitude limit for unsupported human life. A couple of hundred feet higher and the mountain would be unscalable without supplemental oxygen.
Mountaineers arriving at the summit of Everest do so only barely alive, having altered their physiology over weeks, adapting to the challenges presented by the rarefied atmosphere. Here, with or without oxygen, every step becomes a task of Herculean scale. Summiteers describe the excruciatingly slow plod along the last ridge that stands between them and their goal, each stride punctuated by great gasping bursts of hyperventilation as they struggle to repay the oxygen debt incurred. Even after weeks of adaptation, their bodies are only just capable of this feat. An unadapted individual, who hadn’t endured the weeks of acclimatization, would be incapacitated in seconds by exposure to the same altitude.
A typical commercial jet airliner cruises at around 36,000 feet—a few thousand feet higher than the summit of Everest—but the passengers and crew within are breathing normal, low-altitude air. It is only pressurization of the cabin that leaves them able to enjoy in-flight movies and moan about the lack of legroom, rather than loll around unconscious in their seats as a prelude to death from oxygen starvation.
Reduction of pressure causes us problems at high altitude. With fewer molecules of oxygen in every breath, the pressure exerted by the oxygen in our lungs falls and so too does the rate at which it passes across the membranes of the alveoli and into our bloodstream. This leaves our red blood cells, and therefore our tissues, starved of oxygen. You can compensate for that in one of two ways: either by pressurizing your environment—as commercial airlines do—or by increasing the amount of oxygen in the air that you breathe.
Commercial airlines rely upon pressure to keep their passengers properly oxygenated. In preflight safety videos, flight attendants calmly show off the yellow oxygen mask that would pop out of the ceiling and dangle above your seat if cabin pressurization fails. Part of their briefing urges you to behave selfishly, asking that you put your own oxygen mask on before attending to anyone else. But there’s a good reason for this rule. At 36,000 feet, in the absence of supplementary oxygen, a sudden loss of cabin pressure will incapacitate you in less than thirty seconds—roughly the time it would take you to fight a recalcitrant toddler—by which time both of you would be left helpless.
Things only get worse as you ascend. Pilots of unpressurized aircraft have to compensate for the reduction in atmospheric pressure as they climb higher by increasing the concentration of oxygen that they breathe. The lives of World War II bomber crews, flying at altitudes of up to 40,000 feet, depended as much on the oxygen supplied to their face masks as they did on avoiding flak batteries and enemy fighters.
The higher you go, the greater the concentration of oxygen you require in the gases that you breathe. But above 40,000 feet, even pure oxygen isn’t enough to keep you alive. At this altitude, the pressure falls to less than a fifth that at sea level. Here the oxygen doesn’t exert enough pressure to drive itself across the membranes of your alveoli and load the molecules of hemoglobin in your bloodstream.
To support human life at these higher altitudes, oxygen must be breathed under pressure. These more advanced oxygen systems comprise masks that form an airtight seal around the face and then force oxygen into your lungs at a huge rate of flow. Wearing one feels like sticking your head out of the window of a car thundering down the highway and trying to breathe against the rush of air. The effect is to inflate your lungs like a balloon, raising the pressure within them above the ambient pressure of the air outside, facilitating the loading of hemoglobin with oxygen, and thereby ensuring your survival. And even this only works up to a point.
Above 63,000 feet, you encounter the Armstrong line, an atmospheric limit above which the poor oxygenation of your bloodstream is no longer the only factor threatening your life. (Although the Armstrong limit refers to a spaceflight boundary, it takes its name from aviation physiologist Harry George Armstrong, as opposed to he of the “one small step.”)
The Armstrong limit is essentially the altitude at which you begin to boil. Let me explain. Pressure cookers work because the boiling point of water, and all other liquids, rises as ambient pressure rises. Your carrots cook more quickly in a sealed cooker because the pressurized water inside is able to reach a temperature higher than 100°C. (212°F.) before it boils. The reverse is also true: The boiling point of liquids reduces as the pressure falls.
At the summit of Everest, water would boil at a little over 70°C. (158°F.). At around 63,000 feet, the boiling point of water falls further, to 37°C. (98.6°F.), the same as the human body’s normal core temperature. At this, the Armstrong limit, water contained in the tissues of the body spontaneously begins to boil. Bubbles of vapor evolve and expand, swelling soft tissues, causing the body to balloon. It’s interesting that—contrary to sci-fi lore—the blood in your arteries doesn’t boil. The muscular walls of those vessels behave like a crude pressure cooker, preventing the water in the arterial bloodstream from reaching its boiling point.
But in the veins, the story is different. Here the blood flows at much lower pressures, and bubbles of water vapor can and do form. With longer exposure to high vacuums, these bubbles grow and cause airlock, bringing the circulation to a halt and eventually causing cardiac arrest. To avoid this fate, people venturing above the Armstrong line must swap their oxygen masks for pressure suits, surrounding themselves entirely with an artificial sphere of survival. So astronauts wear helmets and bulky sealed outfits, insulated against the ravages of space, taking a little bubble of Earth’s atmosphere with them.
The Armstrong limit defines the height above which simple augmentation of physiology is no longer enough. Beyond this, human life depends entirely upon artificial life support for survival. That layer around Earth, just twelve miles high, represents the narrowest of slivers. If Earth were the size of a soccer ball, then the zone in which life exists unsupported would be thinner than a sheet of paper wrapped around its surface.
—
SPACE BEGINS AT AN INDEFINITE POINT. For physiologists it is the Armstrong limit that marks its threshold, but to aircraft engineers it starts at the von Kármán line, 100 kilometers (328,000 feet, or 62 miles) above sea level. Here the atmosphere is so thin that ordinary aircraft can no longer push against it to steer or generate lift. To the physicist, true space starts many thousands of miles away, where the statistical probability of collision between two gas molecules becomes insignificant. But for astronauts it’s not about altitudes or pressures. For them the frontier of space and all of its attendant risk begins on the launch pad, from the moment the rocket engines light.
I arrived in Florida at the beginning of July 2011, a few days before the big launch. Atlantis stood ready on the pad, waiting to carry its crew of four astronauts into orbit. She was the last of her kind; her sisters Challenger and Columbia had been lost to tragic accidents. Discovery and Endeavour had already been withdrawn from service and now lay stripped down in hangars, being made ready for transport, preparing to take their place as historical exhibits in other cities. This mission was to be the last of the space shuttle program. After three decades and 135 flights, NASA had called a halt to the project.
On the morning of launch, the air outside was humid. Tropical storm fronts had blown ashore one after another in the past couple of days, throwing lightning at the ground and drenching the soil. The weather around Cape Canaveral was always unpredictable in the summer: Blue skies could turn to thundercloud gray in minutes, carrying sudden torrents of rain with them.
For the past twenty-four hours, I’d been glued to meteorological Web sites, trying to make sense of isobars and radar pictures, watching fronts evolve out at sea and migrate inland. I wouldn’t usually care, but today at 11:21 A.M., there had to be nearly cloudless skies above Kennedy Space Center for ten minutes. Whatever happened before or after that didn’t much matter.
Within those ten minutes lay the launch window for Atlantis. They marked the fleeting period when Earth would rotate Pad 39A into just the right position, so that when Atlantis’s engines were lit, the thrust would carry the spacecraft—and her crew of four—into orbit, to arrive at precisely the right place and time to allow her to rendezvous with the International Space Station (ISS).
The space station itself was traveling around Earth at 17,000 miles per hour. That huge velocity gave it enough energy to remain in stable orbit, allowing it to resist the forces that would otherwise bring it crashing back to our planet.
To catch up with that platform, Atlantis had to become a missile, acquiring enough energy to accelerate to the same speed. She would get a little kick from the Earth, borrowing some of the energy of its rotation. Like everything else on the surface of the planet, the launch site wasn’t stationary. It was rotating with the Earth at a little over 900 miles per hour from west to east.
The rockets could make use of that, like a long jumper starting the run-up on a supersonic conveyor belt. While that sounds like a good start, most of the acceleration that would drive Atlantis to more than 17,000 miles per hour had to be achieved through the brute force of rocket engines.
The environment of space is uniquely hostile, but when it comes to orbital spaceflight, the dominant threat to human life comes from the vehicles and their launchers and the way they behave. Two hundred fifty miles, roughly the distance from the surface of Earth to the altitude of the space station, doesn’t sound like a long way. But rocket science isn’t about distance; it’s about defeating the force of gravity and the energy released in accomplishing that feat.
Atlantis was already standing exposed on the launch pad, towering over two hundred feet above sea level. Its fat, orange external tank had been filled overnight with hundreds of thousands of liters of liquid oxygen and hydrogen. Those cryogenically stored fuels, sealed in the insulated tank strapped to Atlantis’s belly, were gently boiling off.
At the pad, the stack was creaking and groaning, straining with the competing thermal stresses of the freezing fuel and muggy warmth of the Florida air. Elsewhere hoses hissed and vapors poured forth. At launch that liquid fuel would feed the shuttle’s three main engines, which sat in a cluster at Atlantis’s rear.
Flanking the tank and the orbiter were the two solid rocket boosters (SRBs). Nearly four meters across and about as long as an Olympic swimming pool, those cylinders were filled with five hundred metric tons of ammonium perchlorate blended with aluminum: an explosive combination studded with oxygen atoms, whose energy was just waiting to be released. That material was combined with a binding agent, leaving it in solid state with the consistency of putty. When lit, it would burn at temperatures comparable to those of the surface of the sun and massively augment thrust in the first two minutes after ignition.
Atlantis had stood waiting on the pad for several weeks, undergoing meticulous final preparations. The orbiters returned from space nearly dead: gliding without power, bodies scorched, fuel and energy spent, engines thrashed to the limits of their endurance. For the hundreds of engineers responsible for turning them around again and returning them to flight, it was an act akin to resurrection.
Tonight was the first time in this mission that Atlantis had been fueled, ready for launch. The perimeter had been evacuated as far back as two miles to all but the most essential staff. Atlantis was dangerous now; the potential energy stored in the chemicals of her external tank and the solid fuel of the rocket boosters was enough to propel the two thousand tons of stack into space at twenty-five times the speed of sound. The groaning, the creaking, and the hissing may have been caused by expanding gases and grating metal, but even the more seasoned engineers regarded Atlantis as though it were an animal slowly coming to life, with a personality of its own.
The countdown clock ticked down to zero. We stood and watched as Atlantis rose into the sky. It felt wrong. Launches always did. It was an event on a scale that didn’t otherwise exist in the world. A massive object racing straight up, far faster than it should be able to, burning engines bright enough to light the entire bank of clouds into which it eventually flew, disappearing in seconds. I stood, breath bated, until the solid rockets separated.
The crew on board knew the risks of their endeavor better than most. As you climb on the highest slopes of Everest, there are points at which you pass the bodies of people who have died on the mountain—a sobering reminder of the consequences of taking such risks. In a similar way, astronauts riding aloft are aware that as they hear the words “go at throttle up,” they are passing the point at which Challenger failed, and they know as they decelerate through Mach 19 on reentry, that Columbia got there—and no further.
—
THE TRICK TO FLYING IS TO throw yourself at the ground and miss. At least that’s how Douglas Adams explained it in The Hitchhiker’s Guide to the Galaxy. While his description was constructed for comic effect, it actually captures—in a strangely accurate way—what astronauts heading into orbit actually do. They climb into vehicles, fire their rocket engines, and hurl themselves across the Earth so fast that they run out of planet to fall onto. Once at that speed, they continue to fall freely around the globe, held by the bond of gravity, unable to escape Earth’s grip or return to its surface. The term orbit simply describes the act of falling toward a celestial body without ever hitting it.
There is, of course, a little more to it than that. The art of rocket science is a discipline filled with everyone’s worst math-class nightmares: calculus stacked upon the mechanics of circular motion framed within exotic coordinate systems. When you get down to the nitty-gritty of building the things, there’s a load of pretty nasty chemistry to bend your mind around, too.
The reality is worse still. The stuff on paper has to be engineered to work in the real world without all of the simplifying assumptions. The nuts and bolts have to travel at many thousands of miles an hour and then fall gracefully through space, precisely as predicted, without flaw or failure. The only way you could make rocket science any more daunting as a prospect would be to add humans into the equation as passengers.
This is the challenge of human spaceflight. No amount of adaptation or acclimatization can prepare the body for exposure to hard vacuum. No amount of augmentation of physiology can make that environment survivable. Instead bubbles of life support must be artificially created, maintained, and sealed against the exterior. These must then be crammed intact into the architecture of a space vehicle, small enough and light enough to respect the great energies demanded by orbital spaceflight but spacious enough to afford at least rudimentary comfort for the crew. When it comes to human spaceflight, throwing yourself at the ground and missing is only half the battle.
—
AS A JUNIOR DOCTOR, I’d occasionally get a chance to spend some time at the Cape, working and researching with the medical team there. Formally it was Kennedy Space Center, NASA’s spaceport, the point on Earth from which every human-rated American space vehicle had ever departed. But to me it was always the Cape. It sat a few dozen miles outside Orlando on the eastern seaboard of the United States, a sprawling government complex reclaimed from wet marshlands in the 1960s for the purpose of doing something outrageous with explosive rocket technology.
From time to time, NASA ran training courses for the civilian medical teams who might be called upon to attend a shuttle accident. We’d gather in lecture halls and receive instruction on the anatomy and physiology of the space shuttle, how it might fail, and what, in theory, we might do to help.
They showed us how the crew could escape a debacle on the launch pad by sliding down a two-hundred-foot-high zip wire, getting from the crew deck to the ground in a few short seconds, crashing into a net, and then bailing into an armored car that they’d been trained to operate. In an emergency, they were told to climb in, drive straight through the perimeter fence, and keep going in the hope that they might outrun the fireball and blast that would accompany the simultaneous detonation of a few hundred thousand liters of rocket fuel.
They showed us too that the shuttle could abort after takeoff during its ascent. Redundancy was the name of the game here. After a few minutes of flight, the mission could tolerate the failure of one of the three shuttle main engines and still get into space, albeit at a lower than intended orbit.
Losing an engine early, before momentum had had time to build, or losing more than one engine, would be a different matter. Unable to develop the altitude or velocity required to achieve low Earth orbit, the shuttle could perform a transatlantic abort, a maneuver in which it would ditch its external tank and solid rocket boosters and vault across the Atlantic Ocean, landing somewhere in Europe.
That journey across the Atlantic Ocean of more than four thousand miles, which a commercial airliner would take perhaps eight hours to cover, would be completed by an aborting shuttle in less than thirty minutes.
There was another, even more outlandish scenario called the return to landing site (RTLS). Here, having lost an engine early in the launch, unable to make it to space, but still strapped to its external tank and two solid rockets, the shuttle could—in theory—be flipped over and flown back to Kennedy Space Center. During this abort, the solid rocket boosters would be jettisoned after two minutes. Then, still strapped to the external tank and at this point heading toward Europe at several thousand miles an hour, the shuttle would ascend and use its maneuvering thrusters to flip itself over, rotating through 180 degrees like a pancake, with its remaining main engines still burning.
Having performed the equivalent of a supersonic handbrake turn, the shuttle’s momentum would continue to carry it toward Europe.
Flying backward with its nose pointing roughly toward the United States, the engines would be facing the direction of travel, thus slowing the shuttle down. At some point, the rocket motors still firing and the external tank still attached, the shuttle’s progress toward Europe would be arrested. Momentarily it would come to a standstill before accelerating once again, this time back toward the States. The crew would then dump their external tank and attempt to glide unpowered back to the site from which they’d launched some twenty-five minutes earlier.
It wasn’t just failure of the engines that could lead to these emergency aborts. Both the transatlantic abort (TA) and the return to landing site could also be used to get the shuttle back on the ground quickly if a significant failure in the life-support system occurred. There was, after all, no point in parking a vehicle in perfect orbit if the crew inside could not be kept alive.
A peppering of euphemisms accompanied these briefings. There was an anticipation that under such conditions, both the vehicle and its crew might return in “suboptimal condition,” that the landings might be “off nominal” in character. Behind this technical phraseology lay the risk that during an abort the shuttle might crash on or short of the runway and the crew might be severely injured in the process.
To civilian clinicians, these abort modes sounded like the stuff of science fiction. Even among the astronaut corps, there was a little skepticism about just how successful a real RTLS abort might be. Nevertheless, they dutifully drilled and trained for the scenarios, sitting fully suited in simulators for hours at a time, rehearsing their worst nightmares.
I often wondered why they bothered to do this when the risk of these types of failures was so low and the chances of recovering intact after one of the more elaborate aborts was smaller still. But like so many other things in exploration and medicine, they did it because the only other alternative would have been to do nothing—which for them wasn’t an option at all.
—
EVEN IF THE LAUNCH GOES SMOOTHLY, there is still the possibility that a medical emergency might arise during a mission, far from the safety of any hospital. Because of this, considerable effort has been invested in designing avenues of escape and medical contingency for space crews. People have even gone so far as to devise ways of resuscitating victims of cardiac arrest. This is no mean feat. Imagine, for a moment, trying to deliver cardiac compressions while floating weightlessly in orbit.
The trick, it turns out, is to strap the patient to the floor of the vehicle, put your hands on the person’s chest, brace your feet on the ceiling, and then use your legs to provide the necessary force. This method has been tested on resuscitation dummies in weightless training aircraft, and it works surprisingly well. But if you’re going to plan for the possibility of cardiac arrest, then you’ve got to consider precisely what you’re going to do after the patient’s heart starts beating again. Contrary to what Hollywood would have you believe, people who survive an arrest of their heart very rarely sit up the instant their pulse returns as though nothing had happened. The experience of total circulatory arrest, along with whatever it was that stopped the heart in the first place, tends to leave one critically unwell. Afterward, a period of extreme instability and a lengthy stay in an intensive-care unit is the norm. For all its sophistication, the International Space Station has less medical equipment and its crew less expertise than are found in the average ambulance. Definitive medical care is available only back on Earth.
It was predicted that during its operational lifetime, there would be at least one major medical incident aboard the International Space Station that would require evacuation to Earth. To allow for this, NASA started work on a new experimental vehicle: the X-38. Standing on the edge of space, looking out across the vastness of the final frontier, NASA was still prepared to go to extraordinary lengths in the hope of saving a life.
—
THERE IS A BLACK-AND-WHITE PICTURE from 1977 of the prototype space shuttle Enterprise being carried along a Californian desert road on the back of a huge articulated truck, being delivered to NASA’s Dryden Research Center for flight testing. Behind it is a snaking line of 1970s motor vehicles. In the foreground sits a man astride his horse, its breath misting in the cold February air. It is a picture of the old world watching the future arrive. That is what we came to expect from the space agency. That’s what NASA did: It served up the stuff of science fiction on the back of a flatbed truck and told you that this was what the future was going to look like.
I was reminded of that image when someone showed me the plans for NASA’s new X-38 back in 2001. It was a wingless vehicle, shaped like a shuttlecock split in half through its nose; a wedge too narrow to allow an adult to stand upright inside, about the size of a luxury speedboat. It was windowless and profoundly alien in appearance. I remember thinking that if it landed unannounced in your back garden, you’d be pretty disappointed if something didn’t then slither out and say, “Take me to your leader.”
The X-38 was destined to be NASA’s Assured Crew Return Vehicle—a way of solving the problem of what to do if an astronaut crew had a really bad day in space. The plan was to load it into the payload bay of a space shuttle, deliver it to the space station, and then leave it docked until called upon.
In the event of some catastrophic failure of systems aboard the space station, the X-38 would become a space lifeboat. The crew would scramble inside, lie down, strap in, and punch out. It was a remarkable design, able to accommodate a crew of seven, shaped so that it could be steered in the upper atmosphere while traveling at hypersonic speeds, and then endowed with the world’s largest parafoil—a steerable canopy that would slow its descent to the ground to ensure a gentle landing. But it was intended to be more than just a fast ride home. In a medical emergency, with members of the crew critically ill or injured, it would essentially perform as a space ambulance, capable of being equipped with medical oxygen, state-of-the-art patient monitoring, and even ventilators.
But as costs mounted and the International Space Station ran into financial trouble, NASA was forced to make cuts. The X-38 was shelved, and NASA returned to relying upon the Soyuz space vehicle as their means of escape. Much smaller than the X-38 and capable of accommodating only three crew members at a time, it was a lifeboat with no real medical capability. But in low Earth orbit, it had become increasingly clear that the dominant threat to human life would not come from crew injury or malfunctioning physiology. There was something that doctors and mission controllers on the ground feared far more than any medical emergency: a catastrophic failure of the vehicles that carried and protected their astronaut crews.
—
SOYEON DIDN’T PLAN ON being an astronaut. She lived in South Korea, a country with no human space exploration program. She watched science-fiction films as a child and fantasized idly about the possibilities of space, but her ambition went no further than that.
She was in her final year of PhD study when the advertisements first appeared in newspapers. South Korea was to run a national competition, casting the net wide in search of the country’s first astronaut. The contest had all the trappings of The X Factor game show: Eliminations would be run week after week over four months, and the competition would be televised. To take part, the only prerequisite was that you had to be over nineteen years old.
Soyeon decided to apply, knowing that she couldn’t possibly be successful. She was a twenty-eight-year-old laboratory scientist working on a graduate degree in bioengineering at the prestigious Korea Advanced Institute of Science and Technology (KAIST), but she didn’t kid herself that she was anything special. She filled in the form anyway. It would be an experience just to be in the running, and a welcome distraction from the final year of PhD study. By the time the closing date for entries arrived in September 2006, thirty-six thousand South Koreans had applied.
The mountain of application forms was screened, excluding those without the right educational background or qualifications and driving the numbers down to something more manageable. A 3.5-kilometer run then served as another coarse filter, this time for standards of physical fitness. The list of hopefuls thinned out quickly. By the end of the first month of selection, there were only 245 people left—Soyeon among them.
Medical examinations, psychological evaluations, and interviews filled the month of October. When Soyeon made it down to the final thirty candidates, she allowed herself the faintest glow of hope.
In November and December came successive rounds of televised elimination. As the tests came and went, Soyeon found herself still in the running. The tasks became more elaborate. The contestants experienced weightlessness aboard a roller-coaster airline ride, dived in swimming pools to simulate spacewalks and neutral buoyancy, and underwent decompression training. The superficial gloss—the studio lights, the spectacle, and the telephone voting—was just that. Underlying all of this was a rigorous process of technical selection of the type that any country might use to select professional astronauts. By the time the ten finalists lined up before the live television cameras on Christmas Day 2006, the assembled hopefuls looked much like the short list for any formal astronaut corps: a clutch of scientists, engineers, and pilots.
There were two winning candidates, a man and a woman. Ko San, a thirty-year-old researcher at the Samsung Advanced Institute of Technology, was the successful male applicant. And standing next to him, blinking in the studio lights when her name was called, was Yi Soyeon.
Things moved quickly after that. Soyeon was told to halt work on her PhD and get ready to report to Star City in Moscow for training. The pace was bewildering. It was the end of December, and they were due to report for training in Russia in three months. At that stage, she didn’t speak a word of Russian and hadn’t yet finished her degree, but none of that appeared to matter to the competition organizers. She was going to Moscow.
Soyeon’s first memories of Moscow were that it was gray and bitingly cold. There in Star City, in parallel with an onerous training regimen, Soyeon finished her doctoral studies. She became a confident Russian linguist, endured survival training, and got to grips with the culture of Russian cosmonaut training. There was initially, she felt, a dismissive attitude toward her from the predominantly male training staff in Russia. But Soyeon was thick-skinned and more than used to handling this sort of behavior. Throughout her engineering studies in Korea, she had pursued courses where women were in the minority and men were often less than progressive in their attitudes. To her, Star City felt little different.
More attention was lavished upon Ko San. Although both Koreans were being trained, only one would eventually fly to the space station, and it appeared to be a foregone conclusion that it would be San and not Soyeon.
After a year of training, when the time came for flight assignment, Soyeon’s suspicions were confirmed. Ko San was awarded the prime slot. Yi Soyeon was to be the backup crew member and, as such, likely never to fly in space. She had loved her experience nevertheless; it had transported and transformed her. Life, she felt, would never be the same again. Meanwhile Ko San prepared for launch, looking every bit the national hero that South Korea had sought to create.
The Russian training teams are notoriously unforgiving of protocol violations. And though the details remain unclear, Ko San somehow managed to anger his Russian hosts. With three months to go before the mission, he was taken off the flight and in his stead Soyeon was promoted to the prime crew.
At first she was incredulous. She had never really expected to fly, but yet now here she was, the prime candidate, due to launch in less than a hundred days. Usually adaptable, Soyeon was worried that she couldn’t adequately prepare in that short time.
This fear continued to occupy her mind as the emphasis of her training changed focus and took on a new seriousness. While having supper one day in Star City, she received a special phone call—one coming live from a module in space. It was Peggy Whitson, NASA astronaut and current space station commander, who was already in orbit. Peggy had heard about the last-minute change in the crew assignments and wanted to reassure Soyeon that she was good to go. During her training, Soyeon had particularly looked up to Peggy. She noticed that wherever the American astronaut went, people appeared to respect her authority. That—Soyeon noted—was rare for anyone and rarer still for a female crew member. If Peggy thought that Soyeon was ready, then maybe she was.
On April 8, 2008, a little over eighteen months after Soyeon had first replied to an ad in a newspaper calling for astronaut hopefuls, she launched from Baikonur Cosmodrome in Kazakhstan aboard Soyuz TMA-12. They took a handful of minutes to climb more than two hundred miles into space. Two days later, their capsule crept toward the International Space Station and docked.
Soyeon’s time on the space station felt like a surreal dream. The assembled modules, joined end to end, gave the crew a free-floating space comparable to that of two commercial airliners. From the outside, it appeared larger still. With its solar arrays unfolded, the station covered an area in the sky the size of two American football fields. Inside, the noise of its power and life-support systems throbbing away was at times loud enough to make ear defenders necessary. It was a reminder that this was more than an assembly of buildings floating in orbit. It was a machine in which people lived, one that, through energy and ingenuity, created an artificial island of human survival in an otherwise uniquely hostile environment.
Soyeon busied herself performing a long list of experiments, taking time out during her ten-day stay to broadcast to schoolchildren and the wider South Korean public. She took the opportunity when she could to steal time in her cabin with its tiny window that looked out at the blue globe of Earth below. All too soon, it seemed, it was time to leave.
On the day of departure, the crew crawled into the confines of the Soyuz capsule. They had to enter in strict order. Peggy Whitson entered first, cramming herself into the left seat. Soyeon followed, finding the rightmost chair. Finally Yuri Malenchenko, who would command the Soyuz capsule on its flight back to Earth, wedged himself between the two. They completed their checklists, and the colleagues whom they were about to leave behind as the new space station crew closed the hatches and sealed them in. There they sat in their bulky pressure suits, contained within their tiny bud of life support, suspended below the International Space Station.
The Soyuz backed off carefully from the station, creeping away at inches per second. There were no forward windows on the capsule; the crew’s view through the small portholes was restricted and mostly looked out to the left and right sides. From her seat, Soyeon could see the vastness of the International Space Station as it slowly receded. For all its artifice and fragility, the space station was an island of security compared with their tiny homebound craft.
The trio hovered below the relative safety of the space station, separated from the ground below by a dense atmosphere and the need to bleed off the tremendous energies they had acquired at launch. They continued to pull away cautiously, taking nearly two and a half hours to put only twelve miles between them and the space station. This excruciatingly slow choreography underlined the vulnerability of both vehicle and station. The structure and systems of both the Soyuz and ISS were finely balanced. Neither was designed for hard collision.
At a safe distance and on schedule, they fired the Soyuz’s rocket motors, slowing themselves down, giving gravity a chance to capture them more firmly. The Soyuz craft comprised three sections. At the front was the oval-shaped orbital module, accessible to the crew only while aloft. Behind it was a cone, the lower half of which housed the propulsion module. In the top part of that cone lay the reentry module, a tiny, bell-shaped vehicle into which Soyeon, Yuri, and Peggy were crammed. Superficially it resembled a giant pawn, taken from a chessboard the size of a soccer pitch.
Shortly before reentry, the crew capsule separated from the other modules. Soyeon, sitting in the right seat, remembered her training for this phase of the flight. Specifically she recalled asking if she’d be able to see the orbital module as they separated from it. The answer was an emphatic no. Her instructor took her through the separation process again step-by-step, explaining that the modules would come apart like beads on a straight piece of wire. If she could see the module after separation, it would mean that something had gone very wrong. And yet, after the pyrotechnic bolts had fired and the thrusters had begun to push them apart, she was sure she had caught a glimpse of part of that module through the porthole above her head.
Concerned, Soyeon reported this to Yuri. At first he thought that she must be mistaken. As the vehicle commander, he had been monitoring the instruments, and all of them had registered a successful separation. He also knew that a nearly catastrophic failure in the separation process would have to have occurred for Soyeon to be able to see something of the separated orbital module from her seat position. Yuri and Peggy were among the most experienced astronauts in Russia and the United States. Soyeon, on the other hand, was a rookie and could have been mistaken. But then Peggy Whitson saw something through her porthole too, apparently drifting over and around their vehicle.
Strapped into their seats, with a limited view of the exterior, it was difficult to know what they had just witnessed. But whatever it was, they knew they shouldn’t have seen it. Worse still, Soyeon now thought that she could see something flapping, still attached, against the outside of the capsule.
Reentry started with the capsule 400,000 feet above the Earth. The weightlessness of orbital spaceflight was replaced by the forces of deceleration as the craft slowed against the atmosphere. Soyeon noticed that the ride was rougher than she’d expected it to be; the G load seemed to be pressing on her chest faster and harder than the 4 G she had anticipated. She reported this to Peggy, who tried to reassure her that the load was normal, and that the experience of ten days of weightlessness might make it feel more intense. But the G load climbed quickly, and soon even Whitson and Malenchenko sensed that things were not right.
The three crew were crammed into the reentry module, sharing just 3.5 cubic meters of space—a couple of telephone booths’ worth. They knew that the module’s survival upon reentry depended upon its ability to adopt exactly the right orientation—with its heat shield facing the direction of travel—as it passed through the atmosphere. It was not the physiological challenge of the space environment that threatened the crew here—it was the sheer violence of reentry.
—
AT LAUNCH, A VEHICLE LIKE SOYUZ must acquire enough kinetic energy to propel its crew at over 17,000 miles per hour. It does this exactly as a firework would, by liberating the chemical potential energy in the launcher and translating it into the kinetic energy of motion. The vehicle could in theory use the same process to slow itself down, but that would require another rocket motor of the same size that got it into orbit in the first place. To avoid having to carry that huge mass into space, the Soyuz slows down by losing energy to the atmosphere as it passes through it.
It’s tempting to think that it is friction that slows the capsule’s progress during reentry. But that’s not what happens. Instead, with the molecules of the atmosphere essentially unable to get out of the way as the reentering vehicle screams through, a shock wave of compressed gas builds up in front of the capsule. Much of the energy of motion is lost in heating that shock wave. The faster the capsule travels, the greater the heat generated. Soyuz is designed to stretch the reentry out over a longer period of time, slowing down more gradually—a bit like the way a Frisbee would sink toward the floor compared with a cricket ball. But even then the front of the capsule reaches temperatures of several thousand degrees—about as hot as the outer layers of the sun.
Human physiology functions very badly if the body’s core temperature rises by just one or two degrees. People begin to die of heatstroke if it rises by more than three. The problem for designers of human-rated space vehicles is how to face a wall of heat of, say, 3000°C. (5432°F.), and then park three astronauts behind it in a tiny capsule, maintaining that pocket and its system of life support at no more than 25°C (77°F.).
This outlandish feat is achieved in two ways. First, the base of the capsule, facing the shock front, is covered in a thermal shield. This layered surface sublimes, transforming from solid to gas as it heats, pushing the hot shock wave in front of the vehicle away as it does. The second element that allows the crew to survive the inferno is a precise angle of entry, which prevents the capsule from heating up too quickly and allows it to fly with the heat shield facing the direction of travel.
But Soyeon knew that they hadn’t separated from their orbital module correctly. Whatever it was that still remained attached could throw things off, leaving the capsule in the wrong orientation as reentry began. If an unshielded part of the capsule was facing forward as they pushed through the dense atmosphere, the heat would very quickly destroy them and their vehicle. If this had happened, then the first indications would be a sudden increase in the G load followed by heat building up inside the capsule.
Inside the capsule, the G meter, measuring the severity of their deceleration, peaked at 8.2 G—more than twice the normal value—and Soyeon struggled to remain composed.
—
IT IS AN OLD ADAGE THAT the two hardest feats in all of rocket science are starting and stopping. These are the so-called dynamic phases of flight, when the vehicle and crew are gaining or losing huge amounts of energy over a short period of time. It was a failure of an O-ring seal at launch that had killed the crew of Challenger in 1986 and a damaged heat shield in one of Columbia’s wings that had destroyed it and its crew during reentry in 2003.
Just as the heat assaulting Soyuz from the outside was at its fiercest, a red lamp began to flash on the control panel. It was a warning light, telling them that something in their systems had failed and that the vehicle was switching to an emergency backup procedure: ballistic reentry. It meant that they were plunging inelegantly through the atmosphere—like the cricket ball rather than the Frisbee. But Soyeon found this strangely reassuring. The Soyuz capsule was designed for this. The ride would be rough, but they should still arrive safely.
After what seemed like an eternity to Soyeon, the violent buffeting stopped, and she felt a jerk as the parachutes opened above them. Unsure of what had happened, they checked their systems. It was at this time that they noticed something that looked like smoke coming from beneath one of the panels. In the cramped space of the Soyuz capsule, nobody could be sure of what they were seeing, but the cloud seemed to hang around Soyeon. With minutes left to go in the descent, the crew’s fears turned to the possibility of fire.
Fire in the confines of the Soyuz capsule would be devastating. The crew decided to power down the electrical systems. The reentry had, after all, been hotter and harder than expected; perhaps something had overheated and caught fire.
Soyeon, however, wasn’t convinced. As part of her PhD, she had worked daily with liquid nitrogen and liquid oxygen. To her this “smoke” looked like the vapors from a cryogenic system. Yuri asked her if she was absolutely certain. “Yes,” she insisted. Reassured, the crew turned their systems back on a short time before landing, but by then they were more than two hundred miles off course.
The capsule hit the ground hard, bouncing before it came to rest on its side in the Kazakh steppe, far from the intended landing site. The crew unbuckled their straps and crawled out, where they were met by a small group of nomadic tribesmen, who initially couldn’t understand where Soyeon and her colleagues had appeared from or how they had arrived. Yuri flicked on a satellite phone and called in their position. It was cold—cold enough for their breath to frost in the air—and they would have to wait more than an hour before their rescuers reached them. But Soyeon was once again back on Earth and safe.
—
FOR ORBITAL FLIGHT, IT IS ENGINEERING and not clever adaptations or augmentation of physiology that saves lives. The nature of spaceflight is such that in its most dynamic phases, the resilience of our physiology and its ability to adapt to the physical extremes of the Earth are utterly irrelevant. The reliance upon artifice is so complete that any significant failure is met with the death of the entire crew. There has never been a mishap in spaceflight in which only part of a crew has been injured or killed. For every accident, the same has been true. Either everything works and everyone lives, or it doesn’t and everyone dies. The first consideration on the way to the final frontier is not about our ability to adapt physiologically. It is about the safety of the evolved engineering solutions.
This recognition of our increasing reliance upon artificial systems to preserve and protect life is not limited to the endeavor of human spaceflight. We push at the edge of the envelope of survival in space exploration in the same way that we take our bodies to extremes in medicine. Evolution has finely crafted the balance between our physiology and the limits of the natural world in which we live. That solution leaves us complex and capable but at the same time fragile. The challenges that we face in future exploration and the limits we would like to probe in medicine far outstrip the spirited but limited resilience of the human body. We no longer explore in the way that Scott and his forebears explored, when determination and self-reliance were the key prerequisites. In this century, exploration will rely almost entirely upon artifice.
—
TEN DAYS AFTER THE LAUNCH, I stood in darkness at the shuttle landing facility, swatting mosquitoes and straining my eyes in vain to try to catch sight of Atlantis. The last mission of the space-shuttle era would land at night, cruelly close to daybreak. We’d be lucky to see anything at all, but we had to come anyway. Somewhere above, the crew of STS-135 was on its way home.
A double sonic boom overhead heralded Atlantis’s arrival. She was circling now, on final approach to Kennedy Space Center, falling unpowered back to Earth, her fuel gone, nearly all of her energy spent. We caught a glimpse of her as she flew through searchlights near the end of the runway, before she touched down out of sight. It’s not how I had imagined it. I thought that the last space shuttle would land in a blaze of illumination and trundle triumphantly across the tarmac, trumpeting the end of an era. Instead Atlantis darted furtively from cover to cover in the half light, gone almost as soon as she’d appeared, vanishing into what remained of the night like a mythical creature.
It had been half a century since Yuri Gagarin first ventured into orbit aboard Vostok 1, in a mission lasting an hour and a half. In those fifty years, the Russians and their American counterparts had learned to work together in low Earth orbit, transforming it into a staging post for still more ambitious feats of exploration. People now permanently lived and worked in space. Low Earth orbit could be visited not just by trained astronauts like Soyeon, but by paying customers. It was time to set sights on new destinations.