Endurance

5

April 3, 2015

MY GOAL FOR most of my adult life has been to pilot aircraft and spacecraft. So it sometimes strikes me as odd that the International Space Station doesn’t need to be piloted at all. When I try to explain this to people who don’t know much about the station, I tell them it’s more like a ship traveling the world’s oceans than like an airplane. Something like the USS La Jolla, a submarine I served on for a few days as a midshipman while still in college, which was self-contained and self-powering. We don’t fly the space station—it’s controlled by software, and even if human intervention is needed, it is controlled by laptops on board or on the ground. We live in the space station, the way you live in a building. We work in it, the way scientists work in a laboratory, and we also work on it, the way mechanics work on a boat, if the boat were adrift in international waters and the Coast Guard had no way to reach it.

I sometimes see the station described as an object: “The International Space Station is the most expensive object ever created.” “The ISS is the only object whose components were manufactured by different countries and assembled in space.” That much is true. But when you live inside the station for months, it doesn’t feel like an object. It feels like a place, a very specific place with its own personality and its own unique characteristics. It has an inside and an outside and rooms upon rooms, each of which serve different purposes, its own equipment and hardware, and its own feeling and smell, distinct from the others. Each module has its own story and its own quirks.

I’ve been on station for a week now. I’m getting better at knowing where I am when I first wake up. If I have a headache, I know it’s because I’ve drifted too far from the vent blowing clean air at my face. I’m often still disoriented about how my body is positioned—I’ll wake up convinced that I’m upside down, because in the dark and without gravity, my inner ear just takes a random guess as to how my body is positioned in the small space. When I turn on a light, I have a sort of visual illusion that the room is rotating rapidly as it reorients itself around me, though I know it’s actually my brain readjusting in response to new sensory input.

The light in my crew quarters takes a minute to warm up to full brightness. The space is just barely big enough for me and my sleeping bag, two laptops, some clothes, toiletries, photos of Amiko and my daughters, a few paperback books. Without getting out of my sleeping bag, I wake up one of the two computers attached to the wall and write down what I remember of my dreams. After my last flight, people were interested in my descriptions of the vivid and surreal dreams I had in space, but I forgot most of them, so I’m making a point of keeping a more consistent dream journal this time.

Then I look at my schedule for today. I click through new emails, stretch and yawn, then fish around in my toiletries bag, attached to the wall down by my left knee, for my toothpaste and toothbrush. I brush, still in my sleeping bag, then swallow the toothpaste and chase it with a sip of water out of a bag with a straw. There isn’t really a good way to spit in space. I spend a few minutes looking over the daily summary sent up by the Mission Control Center in Houston, an electronic document that shows the state of the space station and its systems, asks us questions they came up with overnight, and includes important notes for the plan we’re going to execute that day. There’s also a cartoon at the end, often making fun of either us or themselves. Today’s daily summary shows it’s going to be a challenging day, and these are the days I look forward to.

Mission control schedules our days into increments as short as five minutes using a program called OSTPV (Onboard Short Term Plan Viewer), which rules our lives. Throughout the day, a dotted red line moves relentlessly across the OSTPV window on my laptop, pushing through the block of time mission control has estimated for each task. NASA people are optimists by nature, and unfortunately this optimism can extend to the estimate of how long it will take me to perform a certain task, such as repairing a piece of hardware or conducting an experiment. If I take longer than scheduled to complete a task, the extra time has to come out of something else on the schedule—a meal, my exercise time, the brief time I get to myself at the end of the day (which OSTPV labels “pre-sleep”), or—worst of all—sleep. Most of us wind up having complicated relationships with the line on the OSTPV screen. Sometimes when I’m working on something challenging, the line seems to speed up malevolently, and I could swear something is wrong with it. Other times, it seems to settle down and match the passage of time as I perceive it. Of course, if I could somehow zoom out my view of the schedule wide enough to take in the entire year, the line would be creeping forward so slowly it wouldn’t appear to be moving at all. Today’s schedule seems well thought out, but there are a few ways in which things could go wrong. For Terry, Samantha, and me, much of today is to be taken up with one long task labeled DRAGON CAPTURE.

From the outside, the International Space Station looks like a number of giant empty soda cans attached to one another end to end. The length of the station is made up of five modules connected the long way—three American and two Russian. More modules, including ones from Europe and Japan as well as the United States, are connected as offshoots to port and starboard, and the Russians have three that are attached up and down (we call these directions zenith and nadir). Between my first mission to the space station and this one, it has grown by seven modules, a significant proportion of its volume. This growth is not haphazard but reflects an assembly sequence that had been planned since the beginning of the space station project in the 1990s. Whenever visiting vehicles are berthed here—resupply spacecraft like the Russian Progress, American Cygnus, Japanese HTV, or SpaceX Dragon—for a time there is a new “room,” usually on the Earth-facing side of the station; to get into one of them, I have to turn “down” rather than turning left or right. Those rooms get roomier as we get the cargo unpacked, then get smaller again as we fill them with trash. Not that we need the space—especially on the U.S. segment, the station feels quite roomy, and in fact we can lose one another in here easily. But the appearance of extra rooms—and then their disappearance, after we set them loose—is a bit strange. It used to be that uncrewed cargo vehicles were built as one-use spacecraft, and after we detached them from the station they burned up in the atmosphere. The relatively new SpaceX Dragon has the capability to return to Earth intact, which gives us more flexibility.

I won’t get to spend time outside the station until my first of two planned spacewalks, which won’t be for almost seven months. This is one of the things that some people find difficult to imagine about living on the space station—the fact that I can’t step outside when I feel like it. Putting on a spacesuit and leaving the station for a spacewalk is an hours-long process that requires the full attention of at least three people on station and dozens more on the ground. Spacewalks are the most dangerous thing we do on orbit.

Even if the station is on fire, even if it’s filling up with poisonous gas, even if a meteoroid has crashed through a module and our air is rushing out, the only way to escape the station is in a Soyuz capsule, which also needs preparation and planning to depart safely. We practice dealing with emergency scenarios regularly, and in many of these drills we race to prepare the Soyuz as quickly as we can. No one has ever had to use the Soyuz as a lifeboat, and no one hopes to.

The space station is an international effort and a shared facility, but in practice I spend almost all of my time on the cluster of modules—which, together with American and Japanese visiting vehicles—we call the U.S. operational segment. My cosmonaut colleagues spend the majority of their time on the Russian segment, consisting of the Russian modules as well as the visiting Russian Progress and Soyuz spacecraft.

The module where I spend a lot of my day is the U.S. module formally named Destiny, but which we mostly just call “the lab.” It’s a state-of-the-art scientific laboratory with walls, floors, and ceiling packed with equipment. Because there is no gravity, every surface is usable storage space. There are science experiments, computers, cables, cameras, tools, office supplies, freezers—crap all over the place. The lab looks cluttered—people with OCD would probably have trouble living and working here—but the things I use most I can put my hands on in seconds. There are also a large number of things I would not be able to put my hands on if asked—without gravity, items wander off regularly, and the ground will often email us WANTED posters regarding lost objects, like the ones the FBI puts in post offices. Occasionally one of us will dislodge a tool or part that has been missing for years. Eight years is the record, so far, for a missing object reappearing.

Most of the spaces where I spend my time have no windows and no natural light but rather bright fluorescent lights and clinical white walls. Devoid of any earthly color, the modules seem cold and utilitarian, like a prison of sorts. Because the sun rises and sets every ninety minutes, we can’t use it to keep track of time. So without my watch keeping me on Greenwich Mean Time and a schedule tightly structuring my days, I’d be completely lost.

It’s hard to explain to people who haven’t lived here how much we start to miss nature. In the future there will be a word for the specific kind of nostalgia we feel for living things. We all like to listen to recordings of nature—rainforests, birdcalls, wind in the trees. (Misha even has a recording of mosquitoes, which I think goes a bit too far.) As sterile and lifeless as everything is up here, we do have windows that give us a fantastic view of Earth. It’s hard to describe the experience of looking down at the planet. I feel as though I know the Earth in an intimate way most people don’t—the coastline, terrain, mountains, and rivers. Some parts of the world, especially in Asia, are so blanketed by air pollution that they appear sick, in need of treatment or at least a chance to heal. The line of our atmosphere on the horizon looks as thin as a contact lens over an eye, and its fragility seems to demand our protection. One of my favorite views of the Earth is of the Bahamas—a large archipelago with a stunning contrast from light to dark colors. The vibrant deep blue of the ocean mixes with a much brighter turquoise, swirled with something almost like gold, where the sun bounces off the sandy shallows and reefs. Whenever new crewmates come up to the station for the first time, I make a point of taking them to the Cupola (a module made entirely of windows looking down on Earth) to see the Bahamas. That sight always reminds me to stop and appreciate the view of the Earth I’ve been given the privilege of seeing.

Sometimes when I’m looking out the window it occurs to me that everything that matters to me, every person who has ever lived and died (besides the six of us), is down there. Other times, of course, I’m aware that the people on the space station with me are the whole of humanity for me now. If I’m going to talk to someone in the flesh, look someone in the eye, ask someone for help, share a meal with someone, it will be one of them.

SINCE BEFORE the space shuttle was retired, NASA has been contracting with private companies to develop spacecraft capable of supplying the station with cargo and, at some point in the future, new crews. The most successful private company so far has been Space Exploration Technologies, better known as SpaceX, which produces the Dragon spacecraft. Yesterday, a Dragon launched successfully from the Kennedy Space Center. Since then, Dragon has been in orbit a safe ten kilometers from us. This morning, our aim is to capture it with the space station’s robot arm and attach it to the berthing port on station. The process of grappling a visiting vehicle is a bit like playing an arcade claw machine, except that it involves real equipment worth millions of dollars flying at impossible speeds. Not only could an error cause us to lose or damage the Dragon and the valuable supplies on board, but a slip of the hand could crash the visiting vehicle into the station. A Progress cargo spacecraft once struck the old Russian space station Mir, and its crew was lucky not to have been killed by the rapid loss of atmosphere.

These uncrewed rockets are the only means by which we can get adequate supplies from Earth. The Soyuz spacecraft has the capability to send three human beings to space, but there is almost no room left over for anything else. SpaceX has had a lot of success so far with their Dragon spacecraft and Falcon rocket, and in 2012 they became the first private company to reach the International Space Station. They hope to be able to fly astronauts on the Dragon in the next few years. If they can pull that off, they will be the first private company to carry human beings to orbit, and that launch will be the first time astronauts leave Earth from the United States since the space shuttle was retired in 2011.

Right now, Dragon is carrying 4,300 pounds of supplies we need. There is food, water, and oxygen; spare parts and supplies for the systems that keep us alive; health-care supplies like needles and vacuum tubes for drawing our blood, sample containers, medications; clothing and towels and washcloths, all of which we throw away after using them for as long as we can. Dragon will also be bringing new science experiments for us to carry out, as well as new samples to keep the existing ones going. Notable among the science experiments is a small population of twenty live mice for a study we will be conducting on how weightlessness affects bone, muscle, and vision. Each resupply spacecraft also carries small care packages from our families, which we always look forward to, and precious supplies of fresh food that we enjoy for just a few days, until it runs out or goes bad. Fruits and vegetables seem to rot faster here than on Earth. I’m not sure why, and seeing the process makes me worry that the same thing is happening to my own cells.

We are especially looking forward to this Dragon’s arrival because another resupply rocket exploded just after launch back in October. That one was a Cygnus flown by another private contractor, Orbital ATK. The station is always supplied far beyond the needs of the current crew, so there was no immediate danger of running out of food or oxygen when those supplies were lost. Still, this was the first time a rocket to resupply ISS had failed in years, and it destroyed millions of dollars’ worth of equipment. And the loss of vital supplies like food and oxygen made everyone think harder about what would happen if a string of failures were to occur. A few days after the explosion, an experimental space plane being developed by Virgin Galactic crashed in the Mojave Desert, killing the copilot, Michael Alsbury. These failures were unrelated, of course, but the timing made it feel as though a string of bad luck might be catching up with us after years of success.

I get dressed while I skim over the procedures for the Dragon capture again. We all trained for this thoroughly before launch, capturing many imaginary Dragons using a simulator, so I’m just refreshing my recollection. Getting dressed is a bit of a hassle when you can’t sit or stand, but I’ve gotten used to it. The most challenging thing is putting on my socks without gravity to help me bend over. It’s not a challenge to figure out what to wear, since I wear the same thing every day: a pair of khaki pants with lots of pockets and strips of Velcro across the thighs, crucial when I can’t put anything down. I have decided to experiment with how long I can make my clothes last, the idea of going to Mars in the back of my mind. Can a pair of underwear be worn four days instead of two? Can a pair of socks last a month? Can a pair of pants last six months? I aim to find out. I put on my favorite black T-shirt and a sweatshirt that, because it’s flying with me for the third time, has to be one of the most traveled pieces of clothing in the history of clothing.

Dressed and ready for breakfast, I open the door to my CQ. As I push against the back wall to float myself out, I accidentally kick loose a paperback book: Endurance: Shackleton’s Incredible Voyage by Alfred Lansing. I brought this book with me on my previous flight as well, and sometimes I flip through it after a long day and reflect on what these explorers went through almost exactly a hundred years before. They were stranded on ice floes for months at a time, forced to kill their dogs for food, and nearly froze to death in the biting cold. They hiked across mountains that had been considered impassable by explorers who were better equipped and not half starved. Remarkably, not a single member of the expedition was lost.

When I try to put myself in their place, I think the uncertainty must have been the worst thing. The doubt about their survival would be worse than the hunger and the cold. When I read about their experiences, I think about how much harder they had it than I do. Sometimes I’ll pick up the book specifically for that reason. If I’m inclined to feel sorry for myself because I miss my family or because I had a frustrating day or because the isolation is getting to me, reading a few pages about the Shackleton expedition reminds me that even if I have it hard up here in some ways, I’m certainly not going through what they did.

Out in Node 1, the module that serves largely as our kitchen and living room, I open a food container attached to the wall and fish out a pouch of dehydrated coffee with cream and sugar. I float over to the hot water dispenser in the ceiling of the lab, which works by inserting a needle into a nozzle on the bag. When the bag is full, I replace the needle with a drinking straw equipped with a valve to pinch it closed. It was oddly unsatisfying at first to drink coffee from a plastic bag sipped through a straw, but now I’m not bothered by it. I flip through the breakfast options, looking for a packet of the granola I like. Unfortunately, everyone else seems to like it too. I choose some dehydrated eggs instead and reconstitute them with the same hot water dispenser, then warm up some irradiated sausage links in the food warmer box, which resembles a metal briefcase. I cut the bag open, then clean the scissors by licking them, since we have no sink (we each have our own scissors). I spoon the eggs out of the bag onto a tortilla—conveniently, surface tension holds them in place—add the sausage and some hot sauce, roll it up, and eat the burrito while catching up with the morning’s news on CNN. All the while I’m holding myself in place with my right big toe tucked ever so slightly under a handrail on the floor. Handrails are placed on the walls, floors, and ceilings of every module and at the hatches where modules connect, allowing us to propel ourselves through the modules or to stay in place rather than drifting away.

There are a lot of things about living in weightlessness that are fun, but eating is not one of them. I miss being able to sit in a chair while eating a meal, relaxing and pausing to connect with other people. Eating on the space station, at my workplace, three times a day, while constantly floating and steadying myself, is hardly the same. My egg burrito will float if I let go of it, as will my spoon, egg crumbs, a squeeze bottle of mustard that came up on the last resupply rocket, and a tiny perfect sphere of coffee. The “table” we use for eating has Velcro strips and duct tape to help us keep things in place, but it’s still a challenge to manage all these potentially floating components. I bite the coffee sphere out of the air and swallow it before it can drift into a piece of equipment, or onto a crewmate or my pants (as they need to last six months). The biggest concern is food getting stuck on the hatch seal between modules, one of which is right by the table where we eat. We need to be able to close and seal that hatch quickly in an emergency.

As I’m eating, Terry floats in and wishes me a good morning while looking for coffee. Terry’s astronaut class of 2000 has gotten a raw deal in terms of flight opportunities, since the Columbia disaster grounded the fleet at the same time they completed their initial training and became eligible to fly. Terry didn’t get his chance on the shuttle for ten years. He served as the pilot for STS-130, the mission that delivered the last two modules to the International Space Station—Node 3 and the Cupola. Terry should have then had the chance to command a shuttle mission of his own, but the program ended soon after. He had to wait another four and a half years before flying again, on this mission.

Like me, Terry was a test pilot before joining NASA—in his case, with the Air Force. He has thick dirty-blond hair, a pleasant demeanor, and his default expression is a smile. His call sign is “Flanders,” after the lovably square character Ned Flanders on The Simpsons. Terry has the positive attributes of Ned Flanders—optimism, enthusiasm, friendliness—and none of the negative ones. He is one of a small handful of vocally religious astronauts, and while some of my colleagues are bothered by this, I’ve never had a problem with Terry on this issue or any other. I’ve found him to be consistently competent, and as a leader, he is a consensus builder rather than an authoritarian. Since I’ve been up here and have been commander, he has always been respectful of my previous experience, always open to suggestions about how to do things better without getting defensive or competitive. He loves baseball, so there’s always a game on some laptop, especially when the Astros or the Orioles are playing. I’ve gotten used to the rhythm of the nine-inning games marking time for a few hours of our workday.

Terry eats a maple muffin top while I’m finishing my egg burrito. Next, I eat a pouch of rehydrated oatmeal with raisins. The food portions are small, to discourage waste, so we often wind up eating a few different things for one meal. We are going to have a long morning, and I don’t know when we’ll be able to break for lunch.

My crewmates and I converge in the U.S. lab for the daily planning conference with mission control in Houston, people at other NASA sites, and their counterparts in Russia, Japan, and Europe. I find I’m adapting to being up here quicker than last time, both physically—in terms of living in weightlessness—and in terms of following the routines, using the equipment, doing the work. I have a different outlook this time knowing that I’m going to be here so long. I’m running a marathon rather than a sprint. As I pace myself for a year’s stay, I have to constantly remind myself that for certain things, better can be the enemy of good enough.

The conference generally starts at 7:30 a.m. our time. I say good morning to Samantha, who is already there; Gennady, Misha, and Anton will take part in the conference from the Russian segment. Once we are all assembled, Terry grabs the microphone from its position Velcroed to the wall.

“Houston, station on Space to Ground One, we are ready for the DPC.”

Mission control answers with a bright “Good morning, station!” even though it’s 2:30 a.m. in Houston. We go over the day’s plans for a few minutes, mostly about the details of the Dragon capture. We’d been given a general timeline, but now we nail down exactly what time we need to get started with the procedure, the status of Dragon, whether it’s behaving as expected, and when it will be in certain positions relative to the station. When we are done with Houston, they hand us over to the Marshall Space Flight Center in Huntsville, Alabama. Then Huntsville hands us over to Munich so we can coordinate with the European Space Agency. Then we talk to “J-COM” in the Japanese mission control in Tsukuba, Japan. Then it’s time to talk to Russia: Terry turns it over to the cosmonauts by saying “Dobroye utro, Tsup va Moskvy, Anton pozhaluysta.” (“Good morning, Control Center Moscow. Anton, please.”) Then Anton takes over the mic because he’s in charge in the Russian segment, and he leads the planning meeting with the Russians. Their meeting style is very different from ours—the ground asks the cosmonauts how they are feeling, which seems like a waste of time because they never say anything other than “khorosho”—good. At times I’ve dared them to say “not great,” “just okay,” or even “I feel like shit,” but they refuse to take me up on it even when I offer them money.

The cosmonauts report on the atmospheric pressure of the station, information their flight controllers can see plainly on their own consoles. Next, they have to read back a list of deorbit parameters that, again, the ground already has—they sent them up to us. I find this waste of time maddening, but maybe it’s an excuse to talk to the crew and gauge their moods and frustration levels.

The Russian space agency has a much different system for compensating their cosmonauts than we do: Their base salaries are much lower, but they get paid bonuses for each day they fly in space. (I get only five dollars per diem, but my base salary is much better.) However, their bonuses are decreased whenever they make “mistakes,” those mistakes defined rather arbitrarily. I suspect that complaining, even making very legitimate complaints, can be defined as a mistake, costing them money and, potentially, the chance to fly in space again. As a result, everything is always “khorosho.”

All of this coordinating with sites all over the world might sound time-consuming, and it can be, but no one would ever suggest changing it. With so many space agencies cooperating, it’s important that everyone knows what everyone else is doing. Plans can change quickly, and a misunderstanding could be costly, or deadly. We do this whole circuit of control centers both morning and evening, five days a week. I’ve chosen not to think about how many times I’ll do these before I come back to Earth.

DRAGON IS in its orbit ten kilometers away from us, matching our speed of 17,500 miles per hour. We can see its light blinking at us on the external cameras. Soon, SpaceX mission control in Hawthorne, California, will move it to within two kilometers. Then authority transfers to mission control in Houston. There are stopping points along the way, at 350 meters, then 250 meters, then 30 meters, and finally the capture point at 10 meters. At each stopping point, teams on the ground will check Dragon’s systems and evaluate its position before calling “go” or “no go” to move on to the next stage. Inside 250 meters, we will get involved by making sure the vehicle stays within a safe corridor, that it is behaving as expected, and that we are ready to abort if required. Once Dragon is close enough, Samantha will capture it with one of the station’s robot arms. This is a glacially slow and deliberate process—one of the many things that’s very different between movies and real life. In the films Interstellar and 2001: A Space Odyssey, a visiting spacecraft zips up to a space station and locks onto it, a hatch pops open, and people pass through, all over the course of a few minutes. In reality, we operate with the knowledge that one spacecraft is always a potentially fatal threat to another—a bigger threat the closer it gets—and so we move very slowly and deliberately.

Samantha is going to operate the robot arm from the robotics workstation in the Cupola today (the robot arm’s official name is Canadarm2 because it was made by the Canadian Space Agency). Terry will be her backup, and I will be helping out with the approach and rendezvous procedures. Terry and I squeeze in with her, watching the data screen over her shoulder that shows the speed and position of Dragon.

Samantha Cristoforetti is one of the few women to have served as a fighter pilot in the Italian Air Force, and she is unfailingly competent. She is also friendly and quick to laugh, and among her many other qualifications to fly in space, she has a rare talent for language. She has a native-level fluency in English and Russian, the two official languages of the ISS—she sometimes acts as an interpreter between cosmonauts and astronauts if we have to talk about something nuanced or complicated. She also speaks French, German, and her native Italian, and she’s also working on learning Chinese. For some people who hope to fly in space, language can be a challenge. We all have to be able to speak at least one second language (I’ve been studying Russian for years, and my cosmonaut crewmates speak my language much better than I speak theirs), but the European and Japanese astronauts have the added burden of learning two languages if they don’t already speak English or Russian.

When I first met Samantha, I would have described her as a hip young European; she has a worldly, sophisticated air about her. I found out later that she had participated in foreign exchange programs when she was young, attending high school in Minnesota for a year, spent a lot of time in Germany, and went to Alabama one summer when she was a teenager to attend Space Camp, a simulated astronaut training program. She has a seriously geeky side—she often tweets about science fiction like Doctor Who and The Hitchhiker’s Guide to the Galaxy, and a lot of people were surprised and moved when she tweeted a picture of herself wearing a Star Trek uniform and giving a Vulcan signal out to the cosmos when Leonard Nimoy died. I am impressed with how well Samantha deals with the European Space Agency’s control center in Munich; at times they seem indifferent and inattentive to what we are doing on board, which can be frustrating. She brings good humor to the most boring or annoying situations.

Before Samantha left Earth, she took Terry to her hair salon in Houston so her stylist could teach him to replicate her sleek asymmetrical haircut in space. Haircuts are one of the many tasks ISS crew members have to perform for one another (in addition to giving simple medical tests, drawing blood, doing ultrasounds, and even performing basic dentistry). Terry and Samantha posted pictures of the hairstyling lesson on Twitter, and their followers seemed tickled by the idea that Terry, the upcoming commander of the International Space Station, was being trained as a temporary cosmetologist. Halfway through their mission together, the big day came: Samantha felt her hair was getting too long and asked Terry to get out the equipment. Because we can’t leave bits of hair floating in the air for others to inhale, our haircut equipment includes a vacuum cleaner. Terry tried his very best, but he still screwed it up—the layers that Samantha’s stylist had made seem so easy to replicate under Earth’s gravity were now floating all over the place. Samantha has spent the rest of her mission with her thick, dark hair sticking out from her head in a perfect brush that reminds me of a Russian fur hat.

The capcom speaking to us on the ground today is David Saint-Jacques, a Canadian astronaut. The term “capcom” is left over from the early days of Mercury when the astronauts went to space in capsules—one person in mission control was designated the “capsule communicator,” the sole person in voice contact with the astronaut in space. “Capsule communicator” was shortened to “capcom,” and the name stuck. Today David is talking us through the capture process, announcing Dragon’s position as it moves, controlled by the ground through each of its preplanned stops.

“Station, Houston, on Space to Ground Two. Dragon is inside the two-hundred-meter keep-out sphere.”

The keep-out sphere is an imaginary radius boundary around the station, meant to protect us from accidental collisions. “The crew now has the authority to issue an abort.” This means that we can stop the process ourselves if we lose contact with Houston or if Dragon is outside the corridor. As Dragon approaches station, the early morning light catches the jagged edges of the Himalayas below. The Earth seems to zip by at an impossible speed.

“Houston on Two for rendezvous,” Terry says. “Houston, capture conditions are confirmed. We’re ready for Dragon capture. We’re ready for step four.”

“Copy that, stand by for capture, and just for your situational awareness, we expect that to take us about five or six minutes.” Teams on the ground will give us one final go/no go for capture.

When the Dragon is within ten meters, we inhibit the station’s thrusters to prevent any unintended jolts. Samantha takes control of the robotic arm, using her left hand to control the arm’s translation (in, out, up, down, left, right) and her right hand to control its rotation (pitch, roll, and yaw).

“Station on Two for rendezvous,” we hear from mission control. “You are go for capture sequence.”

“Station copies,” Samantha answers.

Samantha reaches out with the robot arm, watching a monitor that offers a view from a camera on the “hand,” or end effector, as well as two other video monitors showing data describing Dragon’s position and speed. She can also look out the big Cupola windows to see what she’s doing. She moves the arm out away from the station—very slowly and deliberately. Closing the space between the two spacecraft inch by inch, Samantha never wavers or goes off course. On the center screen, the grapple fixture on Dragon grows larger and larger. She makes very precise adjustments to keep the spacecraft and the robot arm perfectly lined up.

The arm creeps out slowly, slowly. It’s almost touching the Dragon.

Samantha pulls the trigger. “Capture,” she says.

Perfect.

“We have nominal capture confirmed at 5:55 a.m. Central Time, while the station and Dragon fly over the northern Pacific Ocean, just to the east of Japan.”

Samantha’s round face has been a study of concentration, her bright brown eyes seeming almost not to blink. The moment capture is confirmed, her face relaxes into a huge smile and she high-fives Terry and me.

Terry speaks: “Houston, capture is complete. Samantha did a perfect job grappling Dragon.”

“Copy and concur. Great job, guys. Congratulations.”

Samantha takes the mic. “I just wanted to say thank you to the folks at SpaceX and you guys in Houston. It’s been just amazing, watching the launch and knowing that it was headed our way and sure enough came knocking on our door. It was steady as a rock and we’re very happy to have it here. It’s exciting to have a new SpaceX dock. There’s lots of science, and even coffee is in there. That’s pretty exciting. So again, thanks a lot and great job to everybody.”

“Thank you, Sam, and thank you, Terry, there’s a bunch of very grateful people on the ground to see this go as smoothly as it has today. Nice job.”

Now control is passing to the robotics officer in Houston (we call him “Robo”), who will maneuver Dragon into a position to be attached to the berthing port on the Earth-facing side of Node 2. Robo is controlling the robotic arm by typing in angles for the joints—they are analyzed by software to ensure the trajectory is safe before they are implemented. Once Dragon is lined up correctly, I will get involved again, monitoring when Dragon comes close enough to the station for “soft” berthing—four nine-inch latches reach out and grab Dragon and pull it into final contact with the ISS—followed by “hard” berthing, sixteen bolts driven through the connection between the space station and the Dragon to securely mate the two spacecraft.

The process of pressurizing the space between the Dragon and the station (the “vestibule”) takes several hours and is important to do correctly. The danger Dragon poses to the station is not over: a mistake in this procedure could cause depressurization. So Samantha and I work through the steps one by one, making sure to do it right. First we check the integrity of the seal between the station and the Dragon by introducing air into the opening between them, a bit at a time. As when we arrived in the Soyuz, if the air pressure inside the vestibule were to decrease, even a tiny bit, that would indicate that the seal has been compromised and that opening the hatch would mean venting our breathable air out into the cosmos.

After a number of iterations of this process—introduce air, wait, measure pressure; repeat—we declare the seal safe, but we will wait until tomorrow to open the hatch. That step requires its own sequence of exacting steps. I’ve seen crews push themselves to get through the entire process because they were so eager to get into their care packages and fresh food. The process takes hours, though, and especially after the morning we spent with capture, it doesn’t seem like a good idea to push things—there’s too much risk of making a mistake. It will take us the next five weeks to unload all the cargo.

WHEN I FLOAT into my CQ for a moment to check my email, it’s the first time I’ve had the chance to pause and think today. The carbon dioxide level is high today, nearly four millimeters of mercury. I can check it on the laptops and see exactly what the concentration of CO₂ is in our air, but I don’t need to—I can feel it. I can sense the levels with a high degree of accuracy based only on the symptoms I’ve come to know so well: headaches, congestion, burning eyes, irritability. Perhaps the most dangerous symptom is impairment to cognitive function—we have to be able to perform tasks that require a high degree of concentration and attention to detail at a moment’s notice, and in an emergency, which can happen anytime, we need to be able to do those tasks right the first time. Losing just a fraction of our ability to focus, make calculations, or solve problems could cost us our lives. And we are still learning about the long-term effects of breathing so much CO₂. It may cause cardiovascular problems and other issues in the future that we don’t yet understand.

My tumultuous relationship with carbon dioxide has been going on as long as I’ve been flying in space. On my first shuttle mission, which was seven days, I was responsible for changing the lithium hydroxide canisters on board that scrubbed the CO₂ from the air. I remember each time I changed the canisters, once in the morning and once at night, I would become aware soon after how fresh the air was—only then did I realize that we had been breathing bad air. Part of our training in advance of flying on the shuttle was meant to let us experience and recognize the symptoms of high CO₂; we each went into a booth in the flight medicine clinic to put on a breathing mask that gave us slowly increasing levels of carbon dioxide.

On my second flight into space, again on the space shuttle, I became more aware of how CO₂ was affecting me and talked with my crewmates about their symptoms. I could pinpoint those moments when the CO₂ was the highest just from the way I felt. I decided to make an effort to start a more serious conversation about its effects. A new space station program manager had just been appointed, and soon after I was back on Earth I helped arrange to bring him on a visit to a Navy submarine under way in the Florida Straits. I thought the submarine environment would be a useful analogy for the space station in a number of ways, and I especially wanted my colleagues to get an up-close look at how the Navy deals with CO₂. What we learned on that trip was illuminating: the Navy has their submarines turn on their air scrubbers when the CO₂ concentration rises above two millimeters of mercury, even though the scrubbers are noisy and risk giving away the submarine’s location. By comparison, the international agreement on ISS says the CO₂ is acceptable up to six millimeters of mercury! The submarine’s chief engineering officer explained to us that the symptoms of high CO₂ posed a threat to their work, so keeping that level low was a priority. I felt that NASA should be thinking of it the same way.

When I prepared for my first flight on the ISS, I got acquainted with a new carbon dioxide removal system. The lithium hydroxide cartridges were foolproof and reliable, but that system depended on cartridges that were to be thrown away after use—not very practical, since hundreds of cartridges would be required to get through a single six-month mission. So instead we now have a device called the carbon dioxide removal assembly, or CDRA, pronounced “seedra,” and it has become the bane of my existence. There are two of them—one in the U.S. lab and one in Node 3. Each weighs about five hundred pounds and looks something like a car engine. Covered in greenish brown insulation, the Seedra is a collection of electronic boxes, sensors, heaters, valves, fans, and absorbent beds. The absorbent beds use a zeolite crystal to separate the CO₂ from the air, after which the lab Seedra dumps the CO₂ out into space through a vacuum valve, while the Node 3 Seedra combines oxygen drawn from the CO₂ with leftover hydrogen from our oxygen-generating system in a device called Sabatier. The result is water—which we drink—and methane, which is also vented overboard.

The Seedra is a finicky beast that requires a lot of care and feeding to keep it operating. It wasn’t until I was a month or so into my first mission aboard the space station that I started to correlate the symptoms I was feeling to specific levels of CO₂. At two millimeters of mercury I feel okay, but at around three I get headaches and start to feel congested. At four, my eyes burn and I can feel the cognitive effects. If I’m trying to do something complex, I actually start to feel stupid, which is a troubling way to feel on a space station. Above four millimeters of mercury, the symptoms become unacceptable. The levels can creep up for different reasons. Sometimes the Seedra has to be shut off because the space station’s orientation isn’t allowing us to collect enough solar energy to power it. For example, when a Progress resupply spacecraft docks, the solar arrays need to be turned edge on so their surface area doesn’t get blasted by its thrusters. At other times there’s no clear reason for Seedra going on strike. Sometimes, it’s just broken.

Much of the management Seedra demands can be done from the ground, which is true for a lot of the hardware up here. Mission control can send a signal to the equipment, using the same satellites we use for email and phone calls. But at times, more serious hands-on maintenance by astronauts is required. The repair process isn’t simple. Seedra has to be powered down and allowed to cool. Then all the electrical connectors, water-cooling lines, and vacuum lines at the bottom of the rack the Seedra sits in have to be removed. All of the bolts holding it in place must be removed so it can slide out. On my previous mission, when I gave Seedra a good tug, it didn’t budge. It felt as if it were welded in place. I had to call to the ground for help, and they had no clue. Many meetings were called over the next few days at the Johnson Space Center while specialists tried to work through the problem.

In that instance, I went over all the bolts again and found one just hanging by a single thread. Problem solved. I pulled the beast out and eventually had to remove all the insulation to expose more electrical connectors, more water lines, and Hydro Flow connectors, which are notoriously tricky to mate. Working on a complex piece of hardware in space is infinitely harder than it would be on Earth, where I could put down tools and parts and they’d stay put. And there are so many complex pieces of hardware up here—NASA estimates that we spend a quarter of our time on maintenance and repairs. The hardest part of repairing the Seedra is replacing all the insulation, sort of like doing a huge 3-D puzzle with all the pieces floating. When we started it up again, it worked. Kelly 1, Seedra 0. I had no idea what it still had in store for me.

On this mission, the two Seedras have been giving us new issues to deal with. The one we use most, in Node 3, has been shutting down when its air selector valves, which are moving parts, get gummed up with zeolite and stick in the wrong position. The Seedra in the lab has an intermittent electrical short that we can’t quite pin down. Sometimes, over the course of a day, the CO₂ level will slowly start to rise, especially when someone is exercising. As the day goes on, I’ll feel congested, with burning eyes and a mild headache. I’ve been using Sudafed and Afrin to fight the symptoms, but these are temporary fixes, and I will quickly develop tolerances. A few days ago, I asked Terry and Samantha how they have been feeling, and they both said they had noticed that when the CO₂ was high they didn’t feel especially sharp cognitively. I’m frustrated that we can’t seem to get any urgency on this issue from the ground.

Part of my annoyance has to do with the fact that even though we have two Seedras on board, the ground allows us to run only one of them, keeping the other in reserve as a backup. We use the one in Node 3 because it works relatively consistently; only if it goes out, or if we have more than six people on board (as will happen in September), will we be authorized to use both. Our CO₂ level could come down to a much more tolerable level with the flip of a switch in Houston, and yet we can’t convince them to do this. I can’t help but to sometimes suspect the second Seedra is kept shut off to avoid the hassle of maintaining it from the ground. It’s hard to work up sympathy for flight controllers who make this decision while breathing relatively clean Earth air. A level of six millimeters of mercury seems unconscionably high to me. The Russian managers claim that the CO₂ should be kept high deliberately because it helps to protect the crew from harmful effects of radiation. If there is any scientific basis for this claim, I have yet to see it. And because (I suspect) the cosmonauts are docked pay for complaining, they don’t complain.

If we are going to get to Mars, we are going to need a much better way to deal with CO₂. Using our current finicky system, a Mars crew would be in significant danger.

THE LAST PLANNING CONFERENCE of the day will be held at 7:30 p.m., and dinnertime is shortly after that. As it’s a Friday, we are looking forward to sharing a group dinner in the Russian segment, as always. Misha is usually the first one ready to start the weekend, and he floats over to the U.S. side in the afternoon to make a plan.

“What time should we start dinner, my brother?” he asks, his blue eyes wide and eager.

“How about eight?” I ask.

“Let’s make it seven forty-five,” he responds.

I agree.

After finishing up the DPC that evening and checking on an experiment, I give Amiko a quick call. “I’m heading over to Boondoggles,” I tell her, jokingly referring to the Russian segment as our neighborhood bar in Houston. She understands what I mean. I start gathering things to bring to Friday dinner in a big ziplock bag. I pack my own spoon and my own scissors for opening food bags. I pack foods to share, stuff from the bonus food container I brought up with me: canned trout, some irradiated Mexican meat, and a processed cheese similar to Cheez Whiz that Gennady loves. The Russians always share some tarry black caviar, for which I’ve developed a real taste, as well as some canned lobster meat. Samantha always brings good snacks, too—the Europeans have the best food.

With my goodie bag under my arm, I float into Node 1, then pass through the pressurized mating adapter (PMA-1), sort of a short, dark entryway between the U.S. and Russian segments. This entryway is not beautiful or spacious; it’s about six feet long and canted up at a steep angle. It’s quite narrow by design, and it’s made even narrower by the cargo we store there in white fabric bags. I pass through the Russian module called the FGB (funktsionalno-gruzovoy blok, functional cargo block), then into the service module. There I find Gennady and Samantha watching a movie on a laptop while Anton floats horizontally to them, finishing up an experiment on the wall. On the laptop, a young woman’s face flickers across the screen, a look of apprehension wrinkling her brow, while a man’s voice speaks sternly in Russian.

“Hey, what are you guys watching?” I ask.

“It’s Fifty Shades of Grey,” Samantha answers, “dubbed into Russian.” In English, Gennady welcomes me and thanks me for the food I’ve brought, then in Russian tries to convince Samantha that Fifty Shades is a great literary work.

“That’s ridiculous,” Samantha says, without taking her eyes off the screen. She and Gennady argue, half-jokingly, about the literary status of Fifty Shades in rapid-fire Russian as Misha emerges from the bathroom. Terry shows up with his own goodie bag and greets everyone.

Anton welcomes us. He flew MiGs in the Russian Air Force before being selected as a cosmonaut, making him one of the people I might have found myself face-to-face with in combat had geopolitics in the early 1990s played out differently. He is solid and dependable, both physically and technically. He has a goofy sense of humor and is a close talker, even for a Russian. He has a halting way of speaking English with pauses in unusual places in his sentences, but I’m sure my Russian sounds far worse. I once asked Anton what he would have done if his MiG-21 and my F-14 had been flying straight at each other on some fateful day—how would he have maneuvered his airplane to get an advantage on me? When I was training and flying as a Navy fighter pilot, these questions about MiGs and their capabilities consumed my fellow pilots and me. All we knew then was guesswork based on military intelligence. As it turns out, the same guesswork was happening on the Soviet side. From Anton and the other cosmonauts I’ve gotten the impression that they didn’t have much knowledge about our airplanes, and the training I got in dogfighting, flying against a very capable pilot in an F-16 pretending to be a MiG, was likely overkill by a wide margin. The Russian pilots are no less talented, they just had much less flight time than we did in our planes (I had more than 1,500 hours of experience in the F-14, while Anton has probably 400 hours in his MiG), presumably because their budgets were limited.

Anton and Misha acted as though Gennady were in charge as soon as he was on board, even though Anton is officially the Russian segment lead. Gennady has been, as always, awesome—things simply seem to go better when he is around, and everyone looks up to him as a natural leader. He doesn’t do anything to try to grab power, but there is something about him that makes people want to listen to him.

Misha has been great to fly with so far too. He has a true concern for other people, and when he asks me regularly how I am doing, he really wants to know. He cares about what’s going on in his friends’ lives, how they are feeling, and what he can do to help. What’s most important to him is friendship and camaraderie, and he brings esprit de corps to everything he does.

I’m often asked how well we get along with the Russians, and people never quite seem to believe me when I say there are no issues. People from our countries encounter cultural misunderstandings every day. To Russians, Americans can at first come across as naïve and weak. To Americans, Russians can seem stony and aloof, but I’ve learned this is just one layer. (I often think of a phrase I once read describing the Russian temperament as “the brotherhood of the downtrodden,” the idea that Russians are bound by their shared history of war and disaster. I thought I read it in The Master and Margarita by Mikhail Bulgakov, but I’ve never been able to find it in any translation; maybe I read it in Russian and this was my own translation.) We make an effort to learn about and respect one another’s cultures, and we have agreed to carry out this huge and challenging project together, so we work to understand and see the best in one another. The crewmates I fly with are crucial to nearly every aspect of my mission. Working with the right person can make the toughest day go well, and working with the wrong person can make the simplest task excruciatingly difficult. Depending on who is up here with me, my year in space could be needlessly perilous, fraught with conflict, or saturated with the everyday annoyance of a person you can’t quite click with and also can’t get away from. So far, I’ve been very lucky.

Once we’re all gathered around the table, Gennady clears his throat and makes a solemn face that lets us know he’s about to make a toast. The Russians are very formal about their toasts, and the first one of the evening is the most important. It’s always to honor the people present and our reason for being together.

“Rebyata,” he starts—“guys”—“can you believe we are here in space? The six of us are the only people here representing planet Earth right now, and I’m honored to be here with you. This is awesome. Let us drink to us and to our friendship.”

“To us,” the rest of us chime in, and the evening has officially begun.

It’s challenging for six people to eat together in such a small space, but we look forward to this chance to have a meal as a crew. We use Velcro and duct tape to secure our dinners, but there is always some stray item—a drink bag, a spoon, a cookie—floating away from its owner and needing to be retrieved. It becomes part of the dining experience to reach out and grab someone’s drink as it floats by your head. We listen to music while we eat, usually my playlist on the iPod I brought with me—U2, Coldplay, Bruce Springsteen. The Russians especially like Depeche Mode. Sometimes I’ll sneak in some Pink Floyd or Grateful Dead. The Russians don’t seem to mind my sixties rock, but they aren’t very interested in hip-hop even though I’ve tried multiple times to introduce them to the works of Jay Z and Eminem.

We talk about how our work has gone during the week. The Russians ask about how the Dragon capture went, and we ask them about how the next Progress resupply schedule is looking. We talk about our families and catch up on current events in our respective countries. If there is significant news involving both the United States and Russia, for instance our two countries’ involvement in Syria, we’ll touch on it lightly, but no one wants to go into any detail. Sometimes the Russians will get caught up in an American news story. For instance, when two inmates escaped from a prison in upstate New York, Gennady and Misha were fascinated with them, asking me repeatedly whether they had been captured. I would find them lingering to watch updates on CNN on our projection screen whenever they had a reason to pass through Node 1.

As the evening goes on, the Russians make their second toast, which is often about something more specific, like current events. This toast is to Dragon and the supplies it brought us. The third toast is traditionally to our wives or significant others and our families. We all stop and think of our loved ones for a moment when Anton makes this toast.

We get to talking about what it’s like to return to Earth in the Soyuz. Most of us have experienced this at least once before—Gennady has done it the most, four times—but for Terry and Samantha, their return in May will be their first time. It’s a wild ride, and the four of us who have done it share our experiences. Gennady tells a story about one of his previous Soyuz flights, when the capsule hit the ground and then rolled around quite a bit, leaving the cosmonauts with their heads below their feet. One of Gennady’s crewmates had tried to smuggle out some souvenirs in his pressure suit, and the extra cargo, along with the strange position they had landed in, left the unnamed cosmonaut with all his body weight on his groin. He was in so much distress that Gennady unstrapped himself, nearly breaking his neck when he landed on his head, in order to help reposition his crewmate and alleviate his pain. Terry and Samantha don’t look too inspired by the story.

Friday night dinners always include dessert. Russian space dessert is almost always just a can of stewed apples. We have much more variety on the U.S. segment, though our desserts aren’t gourmet level. The cherry blueberry cobbler is one of my favorites, and the chocolate pudding is always a big hit with the Russians, so I’ve brought some to share. It drives me nuts that our food specialists insist on giving us the same number of chocolate, vanilla, and butterscotch puddings, when the laws of physics dictate chocolate will disappear much faster. No one gets a vanilla craving in space (or on Earth).

We say our good nights and float back to the U.S. segment, remembering to bring our spoons and leftovers with us. Back in my CQ, I look through the plan for tomorrow, Saturday. As often happens up here, work will continue into the weekend, and I will do my required exercise sessions as well. I take off my pants and secure them under a bungee cord, don’t bother changing my shirt, and brush my teeth. I put on my headset and call Amiko to talk for a few minutes before going to sleep. It’s still early in the evening for her. I tell her about the Dragon capture, about Fifty Shades of Grey, about how the carbon dioxide is bugging me again, about Gennady’s Soyuz story. She tells me about her workday, a lot of which she spent recording an episode of NASA’s Space to Ground web series. Not long ago, she told me that her older son, Corbin, had advised her to take a break from thinking about the space station now and then. “Your work is space, and your home life is space,” he told her. “You never get away from it.” He was right. She is still helping her eighteen-year-old son, Tristan, deal with the consequences of his car having caught fire. She has also been helping my daughter Samantha and running errands for my father. I’m lucky to have Amiko taking care of things for me on the ground, and sometimes it bugs me that I can never do much to help her. This year in space is a test of endurance for Amiko as well, and it’s important for me to remember that.

IT’S STRANGE WAKING UP here on weekends, even more so than waking up other days, because on weekends it becomes clearer that I’m sleeping at my workplace. I wake up Saturday and I’m still at work; wake up on Sunday, still at work. Months later, I’ll still be here. On the weekends we are usually given time to do personal things—videoconference with family, catch up with personal email, read, get a little break from the relentless red line of OSTPV, and get the rest we need to start another week of long days of exacting work.

But there is a certain amount of mission creep into our time on weekends. The couple of hours of exercise on at least one day of the weekend are mandatory, since the damage to our bodies caused by weightlessness does not observe weekends or holidays. And there is station maintenance that can’t be left until Monday, or that we won’t have time to do when Monday comes around. The weekend is also when we clean, and cleaning is a bit more involved in zero gravity. On Earth, dust and lint and hair and fingernail clippings and bits of food fall, so dusting and vacuuming get rid of pretty much everything. On the space station, a piece of dirt can wind up on the wall, the ceiling, or attached to an expensive piece of equipment. A lot of crap winds up on the filters of the ventilation system, and when too much of it starts to build up, our air circulation is affected. Because the walls get dirty and wet, mold is a concern. And because mold spores don’t fall to the floor but linger in our breathable air, they can pose a serious health risk. As a result, we are expected to clean most everything on station we regularly touch every weekend, with a vacuum and antiseptic wipes. We also take samples from the walls to grow in petri dishes and send back to Earth for analysis. So far they haven’t found anything toxic, but it’s both disgusting and fascinating to see what we are cultivating on the walls.

Then there’s the Saturday morning science. When I was up here four years ago, there was an option to participate in additional science work on Saturday mornings, an idea introduced by an astronaut colleague who wanted to volunteer some of his free time to work on experiments that would otherwise go neglected. Since then, astronauts with a special interest in science could participate in Saturday morning science, and those who had other interests, or who—like me—felt they needed time to recover from the stress of the week in order to be ready for emergency situations, were under no pressure to do so. Now Saturday morning science no longer seems optional. In addition to all that, we need to start unpacking Dragon’s cargo. Some of the cargo on Dragon is time sensitive (live mice and fresh vegetables, most notably). Once everyone is up and caffeinated, Terry and Samantha meet me in Node 2. We arm ourselves with checklists and cameras—a still camera to document each step of our work for later analysis by NASA and SpaceX, and a video camera so mission control can see exactly what we’re doing in real time. When we’re ready, we call down to the ground so they can follow along with us.

When Samantha opens the ISS hatch that leads to the Dragon and slides it out of the way, an unmistakable smell hits me—slightly burned, slightly metallic—the smell of space. Samantha smiles at me when she recognizes it. She has smelled it before, when her earlier crewmates went through a process similar to this one to open the hatch on her Soyuz, and again when two of her crewmates did a spacewalk.

We remove and stow a canvas covering that protects the hatch. Then Samantha and I work together to remove the four assemblies that power the latches and bolts that mated the two spacecraft together. It’s a long, involved procedure to remove and properly cap all the connectors. The biggest risk here is damaging one of the connectors or losing a cap, troublingly easy to do when everything is floating around. We connect cables for power and data between the two spacecraft.

We tell the ground that we have successfully completed these steps.

“Station, Houston on Space to Ground Two, you have a go for step six, ingressing Dragon,” capcom tells us.

“Copy that.”

We put on goggles and dust masks before opening Dragon’s hatch to protect us from dust and debris that might be floating inside. Samantha opens the hatch and slides it aside, then turns on the light inside Dragon. The first task is to make sure the air gets mixed between the two spacecraft—there is some danger that Dragon could be harboring a pocket of CO₂ or some other gas, and without gravity to keep the air constantly mixing, we have to install vent lines that will keep air circulating here as it does in the rest of the station. We take samples of the air inside Dragon to send back for analysis on Earth, and the Russians take their own sample (because NASA has sometimes questioned the Russian space agency’s atmospheric standards, they insist on testing our air as well). We visually inspect the area around both hatches to make sure nothing has been damaged. These berthing ports have been used over and over again, and I’m amazed that so far none of them has failed or shown any signs of wear. Everything has gone just as planned, and we now have 4,300 pounds of cargo to unload.

Our care packages are clearly marked and easily accessible once we open the hatch, as are the mice, the fresh food, and ice cream. Terry and I distribute the packages to everyone, feeling a bit like Santa Claus. These items were gathered from our families and friends months ago in order to be packed into the Dragon. Care package items need to be small, light, and nonperishable. I leave mine in my CQ to open in private later.

The fresh food bags contain apples, pears, red and green peppers. They smell great. We will eat them at nearly every meal for the next few days before they spoil.

I unpack the live mice and transfer them, one by one, from the habitat they launched in to their larger, more comfortable facility in the U.S. lab. They scramble around, trying to make sense of weightlessness. I watch their faces and wonder if their tiny brains can process the change they have experienced. Like people, they’re not looking too good at first.

All the cargo we unload from Dragon must be packed into labeled fabric bags. The labels have bar codes, just like food in a grocery store, as well as printed text indicating what’s in each. Everything has a purpose and a destination—not only to go to a certain module, but to go in a specific bag or locker on a specific wall (or floor or ceiling) of that module. It’s so easy to lose stuff up here that if we were to put something in the wrong place, we may never see it again. This makes the work of unpacking Dragon both tedious and stressful, a combination that seems to occur a lot on the International Space Station. After spending a few hours at the interface between Dragon and ISS, I notice that my arms smell like space.

SINCE IT’S SATURDAY, I have a bit more time to make personal phone calls to friends and family. I’ve found myself thinking about my mother today—it’s been three years since she died, and though I’m not usually especially attuned to dates and anniversaries, I’m wishing she could see what I’m doing up here. She was so proud of Mark and me when we became astronauts, and she came to all six of our launches in Florida. The further I’ve gone in my career, the clearer it seems to me that the early lessons she taught Mark and me by example have made a huge difference in my life. Seeing her set herself an incredibly tough goal—to pass the men’s physical fitness test to join the police department—and then to conquer it, was worth more than all the pep talks in the world. I remember watching her post her workout schedule on the fridge, detailing which days she would lift how much weight or how far she would run. As the weeks went by and more of those workouts were crossed out, we saw her get stronger. Her accomplishment wasn’t meant to be instructional for Mark and me, but it was.

All the stories I’ve heard about my mother’s years on the police force made me believe she was the best kind of cop. She truly cared about the people she interacted with, even if they were doing dumb stuff, and she put their safety ahead of her own. She could often defuse a situation by listening rather than threatening, and she made compassionate judgments when it might have been easier to arrest an offender. She hated to take people to jail and would often come home late because she had driven someone home herself instead. My mother sustained a lot of injuries on the job. After ten years, her back ailments had become serious enough that she retired on a disability pension and didn’t work again. She wasn’t sorry to leave; she had found police work very demanding, though she was proud of her service and we were proud of her. She was happy to fill her time with her artwork and, later, her grandchildren.

When I get a chance to float into my CQ, I see that Amiko has emailed me. She put some flowers on my mother’s grave today and took a picture to include in the email. Seeing my mother’s name on her gravestone, the bright colors of the flowers, the green of the grass all around—I’m pulled back to Earth all at once. The image reminds me both of the simple wonder of things like flowers and grass and also of the fact that we have to lose the people we love most. Most of all, I’m moved by Amiko’s gesture. She has a lot to deal with on the weekends, but she remembered this date and drove out to the cemetery to do this because I couldn’t.

“Thanks for doing that,” I tell her when I call. “That means a lot to me.” There was more I wanted to say but I can’t quite put it into words. Amiko was with me at the end of my mother’s life. She was with me when I learned I would be going on this mission. She knows, more than anyone but my brother, what it would mean to my mother to see what I’m doing now.

“I remembered what I wanted to tell you,” I say. “I spent all day getting into SpaceX, and now my arms smell like space.”

“That’s so cool,” Amiko says. “Tell me what it smells like.” She knows, because I’ve told her before. She listens again.

We continue to unpack Dragon on Sunday. I work through a few bags of medical supplies, clothes, and food. I’m taking a break to do some cleaning—it’s still Sunday, after all—and not long afterward I hear a fire alarm.

Astronauts do not scare easily, and this alarm does not exactly scare me, but it certainly gets my attention. Fire is on the short list of things that can kill you in space incredibly quickly. A fire on the old Russian space station Mir blinded and choked the crew within seconds, and if it hadn’t been for their quick reaction they could have died. Some of the older cosmonauts, including Gennady, refuse to cut their hair in space, because Sasha Kaleri was cutting his hair when the fire started on Mir. I know as I hear the first peals of the alarm that I have set it off myself—I’m in the middle of cleaning an air filter, setting free some dust that must have triggered the sensitive smoke detector. Still, an alarm is an alarm, and everyone has to respond according to the checklist. It takes the ground quite a while to recover from the ventilation shutdown that is the automated response to any fire alarm. By the time it’s resolved, I’m in a pretty crappy mood.

ON A MONDAY MORNING a couple of weeks later, I prepare to start working on the rodent experiment, designed to study the negative effects of spaceflight on mammal physiology, with the goal of developing ways to prevent them. So much of the damage to our tissues mirrors the effects of aging—muscle wasting, bone loss, cardiovascular weakening; the solutions that come from these studies will have wide-ranging benefits for humanity, not just for space.

I get out the scalpels, hemostats, tweezers, scissors, probes, syringes filled with sedatives to spare the mice pain, and fixatives to preserve the tissues. I set up the glove box, a glass case with gloves built into the front that lets me manipulate what’s in the box without exposing it to the rest of the station. On Earth the glove box wouldn’t be necessary for this kind of work, but in weightlessness it’s worth avoiding having scalpels and all the rest floating around the lab. I’ve already discovered that the habitat isn’t fail-safe, and I have to constantly look out for small brown UFOs while floating through the lab.

The scientists who design the experiments conducted on station try to minimize the time and attention required from astronauts. There are many experiments going on here that I know absolutely nothing about because they will be worked on by other crew members or because they don’t require human involvement at all, humming along on their own either inside or outside ISS for the entire year. There are others that require only that I push a button or load a new sample once in a while. Some will take more of my time, such as this rodent experiment. I will spend all day with the mice, and the work will be precise and demanding. In order to carry it out, I trained with the scientists in charge of the research before my launch, learning the skills of dissection.

Terry takes the first mouse out of its habitat and slips it into a small container to transfer to the glove box. With nothing to hold on to, she does a slow circle in zero g, working her paws uselessly. I’ve been watching the mice float and wriggle, and it seems as though they have adapted quite a bit and are learning how to get around in this new environment with its new laws of physics. Even their physical condition has appeared to improve since they’ve been here. I set up the cameras for a live downlink with the scientists on the ground in Alabama and California who will talk me through my work in real time. I put the mouse against a piece of wire mesh—since they seem to like to have something to hold on to—then grip the loose skin on the back of her neck, the way you’d scruff a cat, hold the tail between my pinky and ring finger, and slip the needle and syringe full of sedative into her belly.

Once the drug takes effect, Terry puts the mouse into a small X-ray machine. Next I slice into her abdomen, exposing her organs, then insert a syringe into her heart and draw blood into a tiny tube, not unlike the blood I take from myself for the human research studies, except that this step euthanizes the mouse. I put the tube into a bag and label it carefully. Next I remove the mouse’s left eye, following instructions from the ground. That goes into a container and gets labeled. Then I remove her hind legs. This set of experiments is specifically designed to learn about eye damage, bone loss, and muscle wasting. It’s not lost on me that all of the biological processes affecting this mouse are also affecting my own body.

Early in my career as an astronaut I was skeptical of whether I wanted to fly on the International Space Station: most of what station astronauts do is science. After all, I’m a pilot. The goal that had driven me to become an astronaut was to fly more and more challenging aircraft until I got to the hardest thing there was to fly: the space shuttle. Dissecting a mouse is a far cry from landing a space shuttle—but then again, so is unpacking cargo, repairing an air conditioner, or learning to speak Russian, and I do those things too. I’ve come to appreciate that this job has challenged me to do not just one hard thing, but many hard things.

MORE THAN four hundred experiments will take place on ISS during this expedition, designed by scientists from many countries and representing many fields of study. Most of the experiments in one way or another study the effects of gravity. Pretty much everything we know about the world around us is influenced by gravity, but when you can remove that element from the subject of an experiment—whether it’s a mouse, a lettuce plant, a fluid, or a flame—you have unlocked a whole new variable. This is why the science taking place on station is so far ranging; there are few branches of science that can’t benefit from learning more about how gravity affects their subjects.

NASA scientists talk about the research taking place on station as falling into two large categories. The first comprises studies that might benefit life on Earth. These include research on the properties of chemicals that could be used in new drugs, combustion studies that are unlocking new ways to get more efficiency out of the fuel we burn, and the development of new materials. The second large category has to do with solving problems for future space exploration: testing new life support equipment, solving technical problems of spaceflight, studying new ways of handling the demands of the human body in space. All the experiments of which I am the main subject fall into this second category: the study comparing Mark and me as twins over the course of the year; the study on the effects of a year in space on Misha and me; the work being done on my eyes and heart and blood vessels. My sleep is being studied, as is my nutrition. My DNA will be analyzed to better understand the effects of spaceflight at a genetic level. Some of the studies being conducted on me are psychological and social: What are the effects of long-term isolation and confinement?

Science takes up about a third of my time, human studies about three-quarters of that. I must take blood samples from myself and my crewmates for analysis back on Earth, and I keep a log of everything from what I eat to my mood. I test my reaction skills at various points throughout the day. I take ultrasounds of blood vessels, my heart, my eyes, and my muscles. Later in this mission, I will take part in an experiment called Fluid Shifts, using a device that sucks the blood down to the lower half of my body, where gravity normally keeps it. This will test a leading theory about why spaceflight causes damage to some astronauts’ vision.

In fact, there is much crossover between these categories of research. If we can learn how to counteract the devastating impact of bone loss in microgravity, the solutions may well be applied to osteoporosis and other bone diseases. If we can learn how to keep our hearts healthy in space, that knowledge will be useful for heart health on Earth. The effects of living in space look a lot like those of aging, which affect us all. The lettuce we will grow later in the year is a study for future space travel—astronauts on their way to Mars will have no fresh food but what they can grow—but it is also teaching us more about growing food efficiently on Earth. The closed water system developed for the ISS, where we process our urine into clean water, is crucial for getting to Mars, but it also has promising implications for treating water on Earth, especially in places where clean water is scarce. This overlapping of scientific goals isn’t new—when Captain Cook traveled the Pacific it was for the purpose of exploration, but the scientists traveling with him picked up plants along the way and revolutionized the field of botany. Was the purpose of Cook’s expedition scientific or exploratory? Does it matter, ultimately? It will be remembered for both, and I hope the same is true of my time on the space station.

By the end of the day working with the mice, I have a collection of sample bags the scientists on the ground are itching to get their hands on. They will have to wait until we send Dragon back to Earth, but they couldn’t be more pleased with how the dissection went. Terry puts the samples in the freezer. I’m exhausted from the extreme focus and from being locked in one position all day with my hands in the glove box. But it’s satisfying to know my work will be useful. I clean up, putting all the tools and instruments back where they belong, remembering that a tool in the wrong place is no better than a tool we don’t have. I head into Node 1 to find some dinner. We don’t go out of our way to eat together, except on Fridays, because our schedules are just too crazy to allow it. I warm some irradiated meat, douse it in hot sauce, and eat it on a tortilla, floating alone while watching an episode of Comedians in Cars Getting Coffee. While I’m finishing up, Terry comes by.

“Hey, don’t forget we got ice cream on SpaceX,” he reminds me. He goes to the tiny freezer in the ceiling of the lab and brings back a Klondike bar for each of us. It’s real ice cream, not the freeze-dried stuff that’s marketed as astronaut ice cream, which we don’t actually have in space. I’ve never had ice cream in space before—we usually don’t get to eat anything cold. It tastes amazing.

Back in my CQ, I look through my care package that came up on Dragon again. There is a poem and some chocolates from Amiko (she knows I crave chocolate when I’m in space, though on Earth I don’t have much of a sweet tooth); a bottle of Frank’s hot sauce; a postcard from Mark showing twin redheaded little boys giving the finger to the camera; and a card from Charlotte and Samantha, their distinctive styles of handwriting gouged into the heavy paper by a black pen.

I eat a piece of the chocolate and put everything else away. I check my email again. I float in my sleeping bag for a while, thinking about my kids, wondering how they are doing with me being gone. Then I drift off to sleep.