Extreme Medicine (21 page)

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.

—

A
T LAUNCH, A VEHICLE LIKE
S
OYUZ
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.