by Terry Virts
Applying the grease was a fairly straightforward process that was not without a few laughs. Let’s begin with the lube tool itself. Remember the wire ties? Well, we took a wire tie, straightened it out, duct-taped a screwdriver to one end to form a handle, and bent the other end into a V-shaped tray, which was completed with, you guessed it, duct tape. This became our lube tool, another low-tech solution to another high-tech problem. With a giant grease gun in one hand and the lube tool in the other, I squirted grease into the V-shaped tray for the first time and looked away to holster the grease gun. When I looked back up, the grease was gone from the lube-tool tray. I looked around to see if one of my crewmates was there playing a joke on me, but of course I was alone. I didn’t think much of it, put some more grease in the tray, and continued with the procedure, deliberately lubricating each of the sticky bolts in turn. An hour and a half into this process, I was once again holstering the grease gun, only this time in the corner of my eye I caught the grease slowly floating out of its tray, into the darkness of space. I think I yelled “Noooooooooo” in slow motion, immediately realizing what had happened to that first wad of grease. I told Houston, and they told me not to worry about it, just put some more grease in the tray and press on.
Fast-forward a few months later, after I was back on Earth. I was sitting at my desk answering emails when a colleague who worked in the station program walked in and said, “Terry, you might find this interesting.” He had a photo of the exterior of the station, which the new crew in space had taken, showing one of the starboard radiators. Its series of big, white, flat panels had a blemish on it. As we zoomed into the JPEG it was clear; that brown spot was a blob of grease. We laughed so hard—I had left a permanent mark on the exterior of the station, and it was awesome.
I used to say that of the 500 individual tasks that had to be accomplished on every spacewalk, 499 were optional. The only must-do was closing the hatch after your spacewalk. Even if you couldn’t open the hatch at the beginning of a spacewalk, that wasn’t the worst thing that could happen. Although you might be mad, you would be safe inside the ISS. But if you couldn’t close the hatch at the end of a spacewalk, you couldn’t repressurize the airlock with air, and you’d be stuck outside with the rest of your life to figure out how to get that hatch closed. It also turns out that the hatch can be particularly finicky; I’ve since heard tales from other crews who almost wore themselves out trying to get the hatch open or closed. Unfortunately, I didn’t hear those stories until after my flight! At the end of my third spacewalk was the first time I had to close it, and it was a real struggle. I was getting winded.
To visualize the task of closing a hatch, imagine yourself lying on your stomach on the floor, looking down, and in front of you is a big, window-size hatch. You need one hand to hold your body in position because you’re floating, one hand to hold the top handle on the hatch, and another hand to hold the bottom handle, because the whole hatch is basically free-floating and needs to be stabilized. You also need another hand to rotate the latch to seal the hatch once it’s closed. It was a struggle. I would get the top of the hatch pressed against the seal, and then the bottom would pop up. I would grab the bottom handle and push it down, but then the top would pop up. A third hand sure would have been nice. This whole time my other crewmate was completely useless, because he was wedged into the other side of the airlock, head in the other direction, unable to see or reach anything I was doing. Eventually, I figured out how to push the whole hatch firmly against the seal; next, I had to grab the latch and rotate it to the locked position. By this point a fourth hand sure would have been nice. The latch had an arrow indicating clockwise, so I rotated it clockwise and could feel the mechanism moving, but not catching. I kept on rotating it, struggling to keep the hatch firmly in place against the seals, rotating the knob, sweating, and burning up a lot of energy, fighting against the pressurized and bulky spacesuit.
Finally, I read the label on the arrow. Clockwise was the direction to open the hatch, not close it! I thought (not out loud) some bad words, rotated it counterclockwise, and voilà, the hatch grabbed and firmly sealed. And I wondered—why in the world, if you had only one label for one arrow direction, would you make it in the open direction? I laughed quietly to myself, we repressurized the airlock, and all was well. But I learned a few lessons. Build hatches that don’t require four hands to close and have arrows that point in a smart direction.
During airlock repressurization on my second spacewalk, I noticed water pooling on my helmet visor, which seemed normal, probably just sweat dripping off my face and falling onto the visor, since I was looking down. Then I remembered—I was in space, and water doesn’t fall onto anything; it floats! The pool of water was growing bigger by the minute. The spacesuit I was in, serial number 3005, was prone to having a small amount of water leak out, especially during repress. But this blob was bigger than just a few drops and it was still growing. This was a very high-emphasis item at NASA, because two years prior one of my colleagues, Luca Parmitano, had nearly drowned in his suit during a spacewalk. After that close call there were a lot of procedures put in place to mitigate that risk, including installing a snorkel inside the suit and adding an absorbent pad in the helmet.
The water grew until it covered my entire visor and the back of my head was squishy wet, and I finally made the call. “Houston, EV2, I’ve got some water in my helmet. It is probably related to the issues that 3005 has, but I wanted to let you know because it’s covering the visor and I can feel it in the back of the helmet.” I was hesitant to make that call because I knew it would get folks on the ground spun up, including the press, and I was right. While my daughter was driving home from school that day, she heard on the radio, “Astronaut Terry Virts is on a spacewalk and has water in his helmet and might drown.” Exactly what I didn’t want to happen. But I was proud of how calmly the flight control team in Houston handled it. We proceeded with normal airlock repressurization and I got out of my suit quickly, without rushing too much.
The only sound I heard was the faint, high-pitched whine of the spacesuit fan, and my own breathing, and for a few glorious seconds it was just me and the universe.
Our crewmate Anton Shkaplerov floated down from the Russian segment and helped Samantha expedite things. He also used a syringe to measure the exact amount of water that had pooled in my helmet. That measurement allowed me to go outside in that same spacesuit, number 3005, three days later because our engineers were able to narrow down the source of the water to a benign type of leak. Had we not had that syringe data I think NASA managers would still be having meetings to this day, trying to decide whether or not to send me out on the spacewalk.
Ninety-nine percent of my time outside during spacewalks was spent working. I almost always had a face full of equipment and station structure, and I was constantly keeping track of gear, tethers, and the to-do list. I have never felt so on-the-clock as I did during my three spacewalks; there was no time to rest or to pause and take photos. However, during one particular moment on my second EVA, I was at the front of the ISS and had a few seconds to rest. I took that opportunity to rotate my body around and look away from the station and out into space. What I saw changed my perspective on life. There was the most gorgeous sunrise, stretching from horizon to horizon and filling my field of view, beginning as an intense blue to the right and morphing into distinct lines of orange and red and pink. Below was the Earth, black as coal. Above was infinity, blacker than the darkest night you’ve ever seen. The only sound I heard was the faint, high-pitched whine of the spacesuit fan, and my own breathing, and for a few glorious seconds it was just me and the universe. I felt like I was seeing God’s view of creation, something that humans were not meant to see, and I could hear Him tell me, “I am.” That’s all, just “I am.” Adjectives have not been invented to adequately describe this moment, so I won’t torture our language by trying, but you can do your best to imagine.
And then I had to get back to work; th
ere was a power cable that needed to be connected to a cable tray on PMA-2 that would eventually be connected to the capsule docking ring.
You get the point. That moment was a microcosm of my seven months in space. A continuous juxtaposition of the sublime and the mundane, from those first eight and a half minutes during Endeavour’s launch to the end of my 200-day mission, 99 percent of my time was spent repairing equipment and storing gear and putting grease on bolts and running on a treadmill. And 1 percent of it was spent hearing from God and seeing creation from a perspective that I’d never thought possible.
So if you’re planning a spacewalk, remember these things: Keep track of your tethers. Don’t bobble the grease tool. Rotate the hatch knob counterclockwise to shut it. Take a few minutes to look out into the universe and hear from God. Water doesn’t fall down in space. And above all—if you’re going slow, you’re going too fast.
Deep Space
Wired up for a periodic fitness assessment on CEVIS, our space bicycle.
What You Need to Get to Mars
A Realistic Look at What It Will Take
Forty years of multinational, long-duration missions on the ISS, Mir, Skylab, and Salyut have really demonstrated that people can live and work in space for long periods of time. Russian cosmonaut Valery Polyakov even flew a mission that lasted more than 437 days! Proving that humans can thrive during missions lasting half a year or longer has paved the way for future human exploration of our solar system. However, those missions will require long transit times to their planetary destinations, during which the astronauts will be exposed to radiation and weightlessness. Even though we have conquered the standard six-month low-Earth-orbit flight, there are lots of challenges that need to be met if we are to leave the relative safety of Earth and venture out into deep space.
The twenty-first-century goal for human exploration is to get to Mars. The Moon will be an important proving ground to test out the equipment and technologies we will need to get to Mars, but the long-term goal will be the red planet. It is a much more interesting and hospitable destination than the Moon in several key ways. A day on Mars, from sunrise to sunrise, lasts twenty-four and a half hours, very similar to our home planet. A day on the Moon, however, lasts more than twenty-nine Earth days. There is an atmosphere on Mars, albeit very thin, that could be useful. There is water, frozen in the polar ice caps. There may have been oceans on Mars in the past. Mars is much more likely than the Moon to potentially harbor life, if only microbial. The gravity is twice as strong on Mars as on the Moon, and much closer to Earth’s gravity. The radiation environment is much better on Mars because it is farther from the sun. The soil on Mars is similar to that of an Earth desert and could be used for farming, while the soil on the Moon is extremely harsh, more like crushed glass. And the list goes on. If there is an interesting destination in our solar system for humans to visit in the twenty-first century, it’s Mars.
Thankfully, electric propulsion engines can fly much faster than chemical ones and would enable a one-year mission to Mars: four to six months outbound, a month or two on the surface, and another four to six months for the return trip.
Now that you’re convinced that we should send astronauts to Mars, what technologies do we need to develop to go there? Why don’t we just fly there? There are plenty of Hollywood movies where the big spaceship magically appears and off the astronauts go to the red planet, most recently The Martian. Let’s dig into the details of what we need to make this journey happen. The list is significant.
Many types of equipment need to be developed: landers, rovers to carry astronauts, water and air recycling systems that are more efficient and reliable, spacesuits that can be used multiple times in a dusty environment and easily maintained by the crew, lightweight exercise machines, helpful robots, light bulbs that don’t burn out, cleaning equipment that isn’t massive, etc. Equipment reliability is a big issue; twice during my 200-day flight I spent an entire week repairing the carbon dioxide removal equipment, using many bulky and heavy spare parts. Those critical systems need to get more reliable and lighter, and maintenance is an area in which perhaps 3D printing can help. These aren’t insurmountable issues, and our efforts on the ISS and eventually the Moon should be focused on improving equipment in order to enable missions to Mars.
Beyond all of these, there is one overarching piece of technology that needs to be developed—nuclear power. This will serve two purposes: enabling electric in-space propulsion and providing crews with electricity while on the planetary surface. NASA probes have been using nuclear power since the 1960s, generated from RTGs (radioisotope thermoelectric generators). They use a few kilograms of plutonium or other radioactive material that heats up while emitting low-level radiation, warming thermocouples, which then convert heat into electricity. A typical space probe RTG generates a few hundred watts. Because plutonium has a half-life of more than eighty-seven years, they last a long time. In fact, the Voyager probes launched in 1976 still generate roughly 200 watts of power from their RTGs, enough to operate some basic instruments and send very weak radio signals to Earth, despite having actually left the solar system.
These devices are simple, safe, and very reliable. However, they generate only hundreds of watts and are therefore useless for human exploration. We need megawatts to drive in-space engines and kilowatts to run surface life-support systems.
First let’s discuss propulsion. Conventional chemical engines, the kind that rockets have been using for decades, burn a fuel and an oxidizer in a chemical reaction. This type of traditional propulsion requires three years for a human mission to Mars: six to nine months outbound, a year and a half on the surface while waiting for Earth and Mars to orbit the sun and align again, and then another six to nine months for the return trip. I believe that three years is too long; it’s too many supplies to pack, too much radiation exposure for the crew, and too much mechanical malfunction risk. Thankfully, electric propulsion engines can fly much faster than chemical ones and would enable a one-year mission to Mars: four to six months outbound, a month or two on the surface, and another four to six months for the return trip.
Electric rocket engines are nothing new. They have been flying in space for decades, though on a much smaller scale than that required for a human mission. Instead of burning a fuel and oxidizer to shoot exhaust out of the nozzle like a conventional rocket does, electric propulsion uses an electric field to accelerate a charged propellant (ionized gases such as hydrogen or xenon or others) out the nozzle, which may be a magnetic field to contain the ionized gas instead of a traditional metal nozzle. Using this type of engine takes advantage of something called the rocket equation, developed for space travel back in 1903 by the Russian scientist Konstantin Tsiolkovsky. This equation states that the speed at which a rocket can travel is directly related to the speed of its exhaust velocity. Because ionized gas shoots out of the nozzle tens of times faster than traditional rocket exhaust, an electrically powered spaceship can theoretically travel much faster. But there is a rub. . . .
It comes back to that question of electrical power. In order to propel a relatively small satellite, you can use solar power to generate your electricity and use a small electric engine. In fact, this propulsion technique has been used on more than 200 satellites over the past several decades. But people require big, massive spaceships. And in order to make a useful electrical engine that could really get the behemoth moving at the speeds required to shorten that Mars trip to one year, we would need a nuclear reactor generating around 50 megawatts of power. Although reactors of that size are fairly common on Earth, they’ve never been made to that scale for space. Until we have the political will to build those nuclear power plants in space, we will be limited to a three-year round trip to Mars. Which has a tremendous number of implications, none of them good.
First, supplies. You are going to need a lot of food and underwear and water and toilet spare parts if you are going to be gone for three years. You need a lot for a year
also, but three-year round trips would require, well, three times as much. Except the dollar cost is more than three times greater because you need more supply rockets to launch from Earth. You need a much bigger transfer vehicle to take you to and back from Mars. You need a significantly bigger surface presence, with multiple additional modules, to enable a 500-day stay on the surface versus a 50-day stay for the fast trip. Every additional pound of surface equipment and supplies will increase the demand for very expensive landers, which also must be launched from Earth on a greater number of very expensive rockets. Et cetera. Adding two years to a mission is not a linear increase in cost; it is exponential.
One of the most accurate quotes from The Right Stuff is, “No bucks, no Buck Rogers.” The early Mercury program astronauts had grasped a fundamental truth of spaceflight, perhaps more important that Mr. Tsiolkovsky’s rocket equation. The real fuel that makes these spectacular missions fly is money. So let’s talk about the cost of a three-year mission using traditional rockets. NASA’s preferred heavy-lift rocket is known by its very sexy acronym, SLS. Space Launch System. Though some prefer Senate Launch System (more on that later). We have been spending roughly two billion dollars per year on this rocket, going back to 2005 when it was first conceived as Ares V. When it finally flies, maybe in 2022 or 2023, the cost of each launch will be roughly one billion dollars. Let’s forget all of the development costs; they are sunk. I have been told by mission designers at NASA that a single three-year mission to Mars will require seven SLS launches at a minimum. But wait—there’s more! The current expected flight rate for SLS is one launch per year. So, let’s say the seven-launch estimate for one crewed mission is correct, and let’s assume that they can double the flight rate to two per year, which would certainly increase the cost. That means it will take at least three and a half years just to build the Mars ship in Earth orbit before it departs for Mars, with launch costs of seven billion dollars minimum, plus the costs of the landers and modules and spacesuits and equipment and mission control personnel and astronaut salaries (wishful thinking). Because we have been running trillion-dollar annual deficits, I’m afraid our debt-strapped government won’t have unlimited resources in the future for space exploration. We need to find a faster and less expensive way.