16.

Star City, 24 July 2013

People are bustling around me, some in khaki uniforms, others in white aprons. They’re tightening straps, attaching cables, positioning sensors, adjusting things for my height so that I’m comfortable and well supported. I’m in the position I’ll be in on the Soyuz – back parallel to the ground, legs bent – though this seat is much more comfortable. A heavy metal ring, or a sort of mechanical halo, is on a level with my face. Irina Viktorovna, one of the doctors in Star City, comes over and explains that the tests for visual acuity will employ a series of small lights situated on the ring, 80 cm in front of my eyes. Energetic and determined, Irina exudes competence and practicality. During a brief visit a short time ago, she had me lie down on a bed while she put her hands on my sternum, leaning into me with all her weight so I could practise the correct breathing technique: it’s crucial for protecting your heart and ensuring that it continues to function normally while your ribcage is subject to unusual pressure. I’m about to be spun around at 8 Gs, in the world’s largest centrifuge.

The preparation is completed and the technicians push my seat into the cabin, which is hinged on one end of the imposing 18 metre mechanical arm. There’s a metallic sound as the seat locks into position, and then I hear the hatch close behind me. The heavy access doors halfway up in the tall walls of the large, circular hall will also surely be closing now. I’ve watched the centrifuge spin a few times – you can see it through the large windows of the control room above, revolving in all its majesty. All told, it’s quite a simple machine, but powerful in its ability to combine mass and velocity. Some people like precision machinery, say, the workings of a wristwatch, but I have always been fascinated by colossal machines.

Unlike the Soyuz descent module, this cabin is really spacious and somewhat bare, dimly lit by a light that falls mainly on my face. I know that I’m being carefully observed by Irina Viktorovna and the rest of the medical staff. They can see my face in the video images, and the medical belt I’m wearing allows them to monitor my heart and my breathing. I’ve also got a cuff on my forearm that will periodically inflate to take my blood pressure.

For several minutes there’s nothing but silence. Then a voice comes over the speakers to say that the cabin is moving into departure position. The centrifuge starts rotating slowly for the first warm-up exercise at 4 Gs. Increments of 0.1 Gs per second are planned, and the arm accelerates its rotation accordingly. Irina Viktorovna announces that we are passing the 2 G mark, and I begin to feel pressure on my chest. At 3 Gs, I am still able to breathe normally, but I start to use the breathing technique I’ve learned: I contract my chest and neck muscles, thus stiffening my ribcage and airways, and I use my diaphragm to replace some of the air in my lungs. It’s not easy to coordinate these two actions, and I’ve never had much practice with the technique, though it’s a little like the abdominal breathing exercises I’ve practised in yoga lessons over the years. I’ve often heard veteran astronauts say that in this job everything you’ve ever learned proves to be useful at some point or another – and it’s true.

The centrifuge stops for a minute at 4 Gs, then begins to slow down. The warm-up is over, and it didn’t bother me apart from a slight pain in my throat. Next stage: 8 Gs.

Up to now, it’s been a bit of a déjà vu. Last week I experienced in the centrifuge the acceleration profiles for a nominal launch and re-entry in the Soyuz, and during the ascent the peak is in fact around 4 Gs. It occurs at the end of the first-stage burn, when the full thrust from the four side boosters is still available, but the rocket has now become lighter as it has shed the weight of all the propellant it’s already used. That thrust, although produced in a very different way to what occurs in the centrifuge, exerts the same pressure on the chest. Also during the re-entry through the atmosphere, with two typical peaks of 4.3 Gs, the deceleration is felt by the crew in the same direction: chest to back. It’s no coincidence: this is the direction in which G-loads are withstood most easily and with the least risk. The acceleration from the head towards the feet, which you get in aeroplanes, and is particularly intense in acrobatic or combat manoeuvres, is much more insidious since it can cause blood to flow away from the brain, leading to a temporary loss of vision or, in the most extreme cases, loss of consciousness, or G-LOC. To mitigate this risk, pilots are trained to use a special breathing technique and contract their leg, buttock and abdominal muscles to prevent the flow of blood towards the lower parts of the body. The G-suit, which inflates automatically as necessary, contributes in turn by compressing the blood vessels in the lower limbs. Despite precautions, G-LOC does happen, sometimes with fatal consequences. So it made sense that, given the choice, designers of space vehicles decided from the beginning to position the seats in such a way that the effects of acceleration would be directed towards the back.

Given this favourable design, and never having found it difficult to withstand Gs on an aeroplane, I’ve never been very worried about the centrifuge. And indeed, last week’s spinning at 4 Gs went without a hitch. I am, however, a little concerned about 8 Gs, though I’d never admit it and I certainly hope no one notices. First of all, I expect that at some point, discomfort will become pain. More than anything else, though, I find it worrying to have a plot of my heart function transmitted in real time to the medical console. It wouldn’t be the first time that little anomalies in heart function were observed in the centrifuge, and it’s well known how attentive the Russian doctors are, occasionally picking up problems on the plot that wouldn’t concern their Western counterparts. Like any astronaut, the last thing I want is to be an object of discussion for the medical board.

The centrifuge starts up again, and this second spinning, somewhere between 4 Gs and 8 Gs, starts to feel rather uncomfortable, causing an unpleasant ache in my lower sternum. Unpleasant but bearable. The 8 Gs portion will only last for thirty seconds, after all. I know it’s not the case, yet it feels like my lips have stretched all the way back to my ears. I feel tears running down the left side of my face and I know those are real. They told me this might happen: at 8 Gs the eyeball becomes slightly distorted. It’s a temporary effect and nothing to worry about, but it explains the purpose of the visual acuity test I’m about to take. Would I be able to read the instruments and displays in these conditions? Irina Viktorovna spells out the instructions through the speakers. The little lights on the metal ring above my face go on in rapid succession; sometimes they’re placed centrally and sometimes at the margins of my peripheral vision. As soon as I see a light go on, I have to turn it off as quickly as I can by pressing a button I hold in my hand. It’s a simple test of my field of view, and it’s followed by another standard test in which I have to determine on which side there’s an opening in a series of circles. With some effort, I manage to make out the smallest one on my far left. I don’t say anything, however. Irina Viktorovna will ask me for my response later. Though I’m somewhat tempted to try, her instructions are clear: you don’t speak at 8 Gs.

—

It’s embedded in the collective imagination that astronauts regularly practise in the centrifuge and are able to withstand the tremendous acceleration to which they’re subjected thanks to their exceptional physiques and tough training – essential preparation for enduring the rigours of spaceflight. The idea took root in the pioneering era of space travel and is perpetuated by countless documentaries showing the centrifuge making an inevitable theatrical appearance to the sound of pompous narration and dramatic music. Personally, I’m more afraid of the cold. Any healthy person without psychological issues and able to follow simple instructions can withstand 4 Gs; with patience and some tolerance of physical discomfort, even the 8-G exercise. The latter isn’t intended as a test of an astronaut’s stamina; it’s meant to familiarize them with conditions that will be experienced in case of a ballistic re-entry, when the load factor may reach 8 Gs or even exceed that by a considerable amount. Ballistic means unguided: the capsule flies through the atmosphere passively like a rock, affected only by the forces of gravity and aerodynamics, except that it also rotates about its own axis at 13° per second. Unlike a rock, however, the descent module is shaped like a bell, and its mass is distributed so that it will orient itself with its chunky base, protected by a heat shield, in the direction of motion. A ballistic re-entry is definitely uncomfortable, but it’s safe. The Soyuz has brought crew home several times after serious failures thanks to this emergency descent mode, which is solid and reliable.

Many types of malfunction can lead to an unguided re-entry, even in the later stages of descent. For this reason, there are always two search and rescue teams waiting for a crew returning to Earth: the first at the nominal landing site, and the second at the ballistic one. If, however, the re-entry is unexpected – caused, for example, by an emergency on the Space Station – a ballistic re-entry is the only option possible, because the data necessary for a guided descent will not be available to the computer. At that point, you have at least to switch on the engine at the right moment, and that timing is indicated on a special chart called Form 14; this is sent by the Russian Mission Control Centre TsUP every day and is printed and put up in the Soyuz by the commander as the first action of the day after waking. Switching on the engine for a re-entry according to Form 14 means that after a difficult ballistic descent, landing will take place at the most hospitable site available on the ground track of that particular orbit – instead of in the middle of the Pacific, for example, or on top of a mountain in the Himalayas. Either way, there won’t be any rescue teams waiting.

Getting back to Earth alive is dependent on many factors, and astronauts aren’t able to intervene in all of them. Only the descent module, for example, can withstand the heat of the re-entry. Before the Soyuz enters into contact with the atmosphere, the descent module separation must be completed successfully. If the pyrotechnic devices that separate it from the orbital and service modules don’t ignite at the right time, the crew can send the command manually. If the charges still don’t ignite, the entire vehicle will burn up in the atmosphere, and the crew won’t be able to do a thing. At 10 kilometres up, the parachute opens automatically. If it doesn’t open, there’s a reserve parachute. If that one doesn’t open either, the descent module will be destroyed on impact with the ground and, once again, there’s nothing the crew can do about it.

However, there are other situations in which you can and must intervene. If the computer fails, the crew can guide the re-entry using an auxiliary computer, or indeed manually. And if the main engine doesn’t ignite or shuts off too soon, the crew can use the small attitude control thrusters to provide the required braking burn at the right moment for the planned duration and in the correct attitude. This is the key for re-entry to Earth: slowing down just enough but not too much, so that a little later, the Soyuz slips through the upper atmosphere at a precise angle, steep enough to keep it from bouncing away, shallow enough to keep it from hurling itself destructively towards the Earth’s surface. Slowing down at the right moment enables it to land at the designated spot in Kazakhstan, where the rescue team is waiting.

Most of Soyuz training concerns just this: in the simulators, we learn how to perform a re-entry successfully when confronted with unlikely combinations of failures. As far as possible, we try to stick with the automatic, guided re-entry with its peaks of only 4.3 Gs, but we also learn how to promptly recognize the need for a ballistic return. Between these two extremes there are intermediate types of failures in which the computer is unable to guide the re-entry and you can assume manual control of the vehicle and still try to fly along a descent trajectory that’s comfortable in terms of the G-load which the crew will experience, and precise in terms of its proximity to the expected landing point. There has never been a manual re-entry in the history of the Soyuz, but every commander and every flight engineer is trained to perform one.

There’s a specific simulator capable of generating the varying initial conditions of being early or late when making initial contact with the atmosphere. Being early means that you have to fly along a shallower trajectory to prevent the parachute from opening too soon so that you land short of your intended landing site. Conversely, a delay requires a steeper trajectory and constitutes a much more dangerous situation, because if it’s not perfectly controlled, it can quickly bring about an elevated G-load. The Soyuz doesn’t have wings or control surfaces like a plane’s ailerons or its rudder. It can, however, generate a small amount of lift, which it can regulate thanks to a carefully chosen offset of the descent module centre of mass from its axis of symmetry, and a set of thrusters that can make it roll: rolling the capsule in one direction decreases the lift, the descent module follows a steeper trajectory and the landing site moves closer. Rolling in the opposite direction will achieve the opposite effect.

In a nominal situation, the computer regulates the roll, and the crew only monitors the descent on a dedicated page on the command and control display, which shows the calculated trajectory alongside the actual one as the re-entry progresses. The computer is very precise, much more so than a human could be. Just think: in an exam, you receive top marks when you complete the descent – and so the parachute opens – within 10 kilometres of the planned location. But the maximum acceleration achieved should also be considered; it should never exceed a limit of between 4 Gs and 6 Gs depending on initial conditions. Quite apart from your exam marks, you would literally feel the consequences of an excessive G-load first-hand in your body. The re-entry through the atmosphere may be simulated, but the Gs are real, since the exam takes place in the centrifuge.

After the two familiarization runs, I would sometimes spin at the end of the long mechanical arm, no longer a passenger, but actually at the controls, by means of the re-entry simulation. In front of me would be the Soyuz control panel, and I’d hold the descent control device, an old-fashioned-looking gizmo connected by a cable to the on-board systems. Two large handles at the side allow you to hold it comfortably and securely, even if you have to grip it wearing Sokol gloves, which may actually be pressurized due to an ongoing emergency. It’s easy to push the two control buttons with your thumbs: one rolls the descent module in one direction; the other makes it roll in the opposite direction. Two buttons. That’s it.

It wasn’t instantly clear to me how such elementary commands could be translated into the correct management of the trajectory. After the first simulator sessions, I was quite puzzled: the Soyuz was not only rather sluggish in its response to commands, but also quite unpredictable in its behaviour, due to the unequal density of the different atmospheric layers and the varieties of centres of mass that were simulated. During a supper at Cottage 3, after one of the first drills, I made my colleagues laugh when I jokingly said that in some simulations flying the Soyuz was like flying a glider, in others a clothes iron. Their laugh was one of kindness and understanding. All the astronauts who’d come through training before me had gone through the same experience. They gave me an unofficial cheat sheet, handed down from one crew to another and adapted by each according to individual preferences. It wasn’t the solution to all problems, but if nothing else, it allowed you to handle the beginning of the descent correctly without thinking about it too much. What do you do if your contact with the atmosphere is delayed by thirty seconds, for example? Immediately initiate a 45° rotation to the left in order to start the steepest descent possible; but after you pass 3 Gs, you promptly rotate 45° to the right, in order not to exceed 5 Gs, the maximum allowed. It was a safe starting manoeuvre, allowing time for you to observe the vehicle’s behaviour: from that point on, it was an art.

Whenever I found myself back in training in Star City, I had two or three simulator sessions a week with Dima, who patiently loaded one scenario after another. Repetition is the mother of learning, as the Russians love to say. In fact, things did slowly improve, and I was relieved to discover one day that I wasn’t getting it wrong any more. I’d joined the ranks of those who’d overcome the initial confusion, and I could now begin passing on my experience to the astronauts coming up after me in training, just as Reid and the other flight engineers from earlier crews had done for me.

Luca, too, had shared his techniques for coping with the re-entry simulator. We hadn’t seen each other much over the last three years, because Luca and his family had moved to Houston right after his assignment. Every now and then we’d run into each other in some part of the world or other, when the little boxes on our trip templates showed the same colour. I’m the kind of person who needs regular doses of silence and solitude, but Luca is extremely extroverted, always eager to share his stories and experiences. Even just a short time before we said goodbye in Star City ahead of his departure for Baikonur, he actually took the time to explain techniques he’d found useful, not only in the descent simulator, but also in manual docking.

At the end of May, I followed Luca’s launch from ASI headquarters in Rome, commenting from the stage on the images transmitted from Baikonur. There was a large crowd, including his family and friends. We all burst into applause, relieved when shots from inside the Soyuz showed floating objects – Luca, Karen and Fëdor were in orbit. You don’t indulge in your own, heartfelt emotions in the midst of a crowd, but later, when most of the guests and journalists had gone away, knowing that Luca was in his Soyuz moving towards the Space Station really affected me. The first of the Shenanigans was in space. It was four years since the selection, a short time compared to the average time an astronaut waits for a first flight. It seemed like yesterday that we’d crossed the threshold of EAC together in Cologne, but we’d learned so much since then, had had so many experiences and met so many people – Luca, the other Shenanigans and I. And now Luca was in space, something both expected and extraordinary. Three years before, I wished I had been assigned to that flight myself. But now I felt almost grateful not to be in his shoes. Luca was ready, without a doubt, but it seemed to me that it had all come too quickly for him.