I slid into the pants of the suit, and Kimiya helped me squeeze into the hard upper torso. Nearly dislocating my shoulders and hyperextending my elbows, I pushed my arms into the sleeves and my head through the neck ring. Kimiya connected my liquid cooling garment umbilical, then sealed the pants to the torso. Each connection between pieces of the suit is critical. The last step was to put my helmet on. My visor had been fitted with Fresnel lenses to correct my vision without me having to wear glasses or contacts. Glasses can slip, especially when I’m exerting myself and sweating, and I can’t adjust them when I’m wearing my helmet. Contact lenses would be an option, too, but they don’t agree with my eyes.
Once we were suited up, Kimiya floated us into the airlock—first me, then Kjell—allowing us to conserve our energy for what was to come. We floated and waited for the air to be pumped out of the airlock and back into the station. Air is a precious resource, so we don’t like to vent it out into space.
Tracy’s voice breaks the silence: “All right, guys, with Scott leading, we will begin translating out to your respective work sites.”
By “translate,” she means to move ourselves, hand over hand, along a path of rails attached to the outside of the station. On Earth, walking is done with the feet; in space, especially outside the station, it’s done with the hands. This is one of the reasons why the gloves of our spacesuits are so critical.
“Roger that,” I tell Tracy.
I translate out to my first work site, on the right side of the giant truss of the space station, occasionally looking back to see how my tether is routed and making sure it doesn’t get snagged on anything. At first, I feel like I’m crawling hand over hand across a floor. I’m immediately struck by how damaged the outside of the station is. Micrometeoroids and orbital debris have been striking it for fifteen years, creating small pits and scrapes as well as holes that completely penetrate the handrails, creating jagged edges. It’s a little alarming—especially when I’m out here with nothing but a few layers of spacesuit between me and the next strike.
Being outside is clearly an unnatural act. I’m not scared, which I guess is a testament to our training and to my ability to compartmentalize. If I were to take a moment to ponder what I’m doing, I might completely freak out. When the sun is out, I can feel its intense heat. When it sets, forty-five minutes later, I can feel the depths of the cold, from plus to minus 270 degrees Fahrenheit in minutes. We have glove heaters to keep our fingers from freezing but nothing for our toes. (Luckily, my ingrown toenail has healed after a few weeks without any further intervention or this would be even more uncomfortable.)
The color and brilliance of the planet, sprawling out in every direction, are startling. I’ve seen the Earth from spacecraft windows countless times now, but the difference between seeing the planet from inside a spacecraft, through multiple layers of bulletproof glass, and seeing it from out here is like the difference between seeing a mountain from a car window and climbing the peak. My face is almost pressed against the thin layer of my clear plastic visor, my peripheral vision seemingly expanding out in every direction. I take in the stunning blue, the texture of the clouds, the varied landscapes of the planet, the glowing atmosphere edging on the horizon, a delicate sliver that makes all life on Earth possible. There is nothing but the black vacuum of the cosmos beyond. I want to say something about it to Kjell, but nothing I can think of sounds right.
My first task is to remove insulation from a main bus switching unit, a giant circuit breaker that distributes power from the solar arrays to the downstream equipment, so the unit can later be removed by the main robotic arm. This is a job that would normally require a spacewalk, but we are trying to use the robot arms to do more work.
Kjell’s first task is to put a thermal blanket on the Alpha Magnetic Spectrometer, a particle physics experiment. It’s been sending back the kind of data that could alter our understanding of the universe, but it needs to be protected from the sun if it’s going to continue doing its job—it’s getting too hot. The spectrometer was delivered to the station by the last flight of Endeavour in 2011, which was commanded by my brother. Neither of us would have guessed five years ago that I would be leading a spacewalk to extend its lifespan.
The Hubble Space Telescope and other instruments like the AMS have transformed our understanding of the universe in recent years. We had always assumed that the stars and other matter we could observe—200 billion galaxies each with 100 billion stars on average—made up all of the matter that existed. But we now know that less than 5 percent of the matter in the universe is actually observable. Finding dark energy and dark matter (the rest of what’s out there) is the next challenge for astrophysics, and the AMS is searching for them.
Removing and stowing the insulation from the main bus unit is a relatively simple task for a spacewalk, but as with everything we do in zero g, it is harder than you would think—sort of like trying to pack your suitcase if it were nailed to the ceiling. The focus required to do even simple work in space is daunting, similar to the focus required to land an F-14 Tomcat on an aircraft carrier, or land the space shuttle. But in this case I have to maintain that focus all day, rather than only for a matter of minutes.
The three most important things to keep track of today are what I think of as the three T’s: tethers, task, and timeline. From moment to moment, I have to be aware of my tethers and whether they are properly attached. There is nothing more important to my continued survival. In the medium term, I have to focus on the task at hand and on completing it properly. And in the long term, I have to think about the overall timeline for the spacewalk—the scheduled sequence of tasks planned out to make the best use of our finite suit resources and our own energy.
When I finish removing the insulation and stuffing it into a bag, I get congratulations from the ground for a job well done. For the first time in hours, I take a deep breath, stretch as best I can in the stiff spacesuit, and look around. This would normally be a good time to break for lunch, but that’s not on today’s schedule. I can sip water through a straw in my helmet, but that’s it. I’m making good time and still have a lot of energy. We are going to be able to nail this spacewalk, I think to myself. As the day goes on, it will become clear that this is a false sense of confidence.