ESSAY: The Complexity of the Humble Spacesuit
The publisher of the 2012 anthology Rocket Science has kindly granted me permission to post my essay from that book, which has been nominated for the BSFA Non-Fiction award. If you enjoy this piece, please consider purchasing the anthology from Mutation Press.
Throughout the history of spaceflight, every aspect turns out to be a bit harder than it would appear at first blush. Rocket fuel, launches, weather, lightning, radiation, landings, robotics, automation or lack thereof, redundancy, edible food, mission control, psychology, communications… the list goes on and on. Consider the humble spacesuit. It’s often taken for granted in science fiction, unless it is about to fail in a particularly dramatic way. After all, there’s an air-tight suit, you pump air into it, the astronaut breathes, and you’re good, right? Well, not quite.
It’s a bit more complicated than simply strapping some scuba tanks on your back. We breathe in oxygen and breathe out carbon dioxide and water vapour, with a whole bunch of nitrogen involved as well. We can ignore the nitrogen, about which more later, but there’s still the matter of keeping the astronaut from suffocating in her own exhaled carbon dioxide. Rebreather technology is only one small component of the overall system. There’s also the matter of all the water we exhale with every breath; dehumidifying the air is a must in order to keep the suit from turning into a rain forest. So that’s at least two systems to fit into the life support backpack.
The more air and pressure you have in there, the more comfortable for the astronaut, right? If there’s as much oxygen in there as there would be at the beach in California, everyone will be happy. Except… air pressure at sea level is 101.325 kPa (14.7 psi), which we never notice because we evolved for it. However, if you put that much pressure into a space suit in a vacuum it blows up like a mylar balloon and becomes almost as rigid as steel. It’s impossible to move or manoeuvre. Skipping on the nitrogen (which makes up more than three-quarters of the volume of terrestrial air, but is inert) lets us save on air volume and thus air pressure. But when you start messing around with pure oxygen and different air pressures, you face some of the same challenges that face deep-water scuba divers, including the risk of getting the bends (decompression sickness). According to Mary Roach in her superb book on space travel, Packing for Mars:
Alexei Leonov [the first human to make a spacewalk] is said to have sweated away 12 pounds in a similar struggle. His suit had pressurized to the extent that he could not bend his knees and had to go in head first, rather than feet first, as he had trained for. He got stuck trying to close the hatch behind him and had to lower his suit pressure to get back in a potentially lethal move, akin to a diver ascending too quickly.
The space suits worn by present-day astronauts are very bulky, and not much loved by the astronauts themselves. They solve the pressure problem by having relatively low air pressure, and also by reinforcing the joints and having other hardened elements. Counter-intuitively, making them stiffer keeps them from being as affected by the internal air pressure. The joints must then be complexly hinged with ‘mobility bearings’ in order to be usable. Even with the suits as manoeuvrable as they are, it is almost impossible to get in and out of them without considerable help from another astronaut. A future proposal involves designing a spacesuit to be more like a neoprene wetsuit. It would be airtight, of course, but having something skin-tight combats the vacuum of space by elastically compressing the astronaut’s skin and may end up being more comfortable and manoeuvrable. This idea was not, however, picked up by NASA for its next-generation spacesuit.
In a nice illustration of the link between space exploration and deep-sea diving, the contract for that next spacesuit was awarded in 2009 to Oceaneering International, a company that got its start supporting underwater drilling operations. And spacesuits are being asked to do more and more as NASA looks to the future. In Oceaneering’s suit project, this is what NASA says it is looking for:
Suits and support systems will be needed for as many as four astronauts on moon voyages and as many as six space station travelers. For short trips to the moon, the suit design will support a week’s worth of moon walks. The system also must be designed to support a significant number of moon walks during potential six-month lunar outpost expeditions. In addition, the spacesuit and support systems will provide contingency spacewalk capability and protection against the launch and landing environment, such as spacecraft cabin leaks.
This is another evolutionary step beyond what we currently have, which only supports spacewalks with no concern about different gravity conditions (free-fall in orbit versus a planetary or lunar surface) or erosion from working on a planet’s surface.
It’s a cliché, those cold dark depths of space. Actually, Low Earth Orbit switches from hot to cold almost instantly, depending on whether you’re in direct sunlight or not. In sunlight, the temperature can get as high as 121º C (250º F), and in the shade it can quickly fall to -157º C (-250º F). And if you’re hot, it’s surprisingly hard to cool down in space. While the ‘temperature’ of space is quite low (there are very few particles around to collide, which is what ‘heat’ really is), vacuum itself is a fantastic insulator. That’s why vacuum-sealed thermos flasks are so effective. On Earth things cool off via three methods: conduction (a hot material in contact with a cool material will lose heat to the cooler object), convection (the movement of fluids around a hot object, such as water or air, will carry heat away), or radiation (an object will lose energy to the surrounding environment). In space, only radiative cooling is available, and that is a very slow process. It is easier for an astronaut to bake—heating up via his own exertions plus exposure to the sun—than to freeze. Current spacesuits are usually cooled by tubes of water running through a layer of the suit, much like a refrigerator system, and that makes up a large part of that bulky backpack.
If you’re out and about outside your spacecraft, it’s probably because you need to do some work. And we, clever monkeys that we are, do work primarily with our hands. So gloves are extremely important: they have to be durable (a tear would be disastrous), insulated (fingers must not freeze or burn when in contact with metals like the exterior of the space station), and dexterous (allowing for bolt tightening, button pushing, and any number of other construction tasks). And getting all three of those things in one design is nigh-unto-impossible. Mary Roach got to experience the gloves at NASA Johnson Space Center:
The spacesuit systems lab at Johnson Space Center has a glove box that mimics he vacuum of space and inflates a pair of pressurized gloves. In the box with the gloves is one of the heavy-duty carabiners that tether astronauts and their tools to the exterior of the space station while they work. Trying to work the tether is like dealing cards with oven mitts on. Simply closing one’s fist tires the hand within minutes.
One solution involves an outer mitten for insulation and tear protection and a thinner heated inner glove for detail work. But a better design would be greatly appreciated.
FOOD AND WATER
When an astronaut is working hard for hours at a time (the longest spacewalk so far lasted almost nine hours), and sweating up a storm, she’ll need to drink to rehydrate and eat something to keep going. The drinking system is somewhat like a bicyclists’ Camelbak pack, with potable water and a straw near the mouth. Unfortunately it’s been known to leak, which is no fun. There is also a slot for an energy bar, where the astronaut can take a bite and move the bar up for the next bite… However, the annoyance of crumbs floating in the helmet is so great (there’s no way to clean them up with the helmet on) that most astronauts simply have a big meal before a space walk and skip on the snack. And how about that sweat? Can you imagine embarking on a construction project on a hot, humid day and never being able to wipe your brow? Sweatbands and wicking garments only take you so far.
How long will an astronaut need to stay in a spacesuit? Gemini 7 was a two-week mission with Jim Lovell and Frank Borman, and the flight doctors decided that they needed information on the effects of long-term spacesuit wearing. As the wonderfully named Christopher Columbus Kraft Jr, the flight director (for whom Johnson Space Center’s Mission Control building is now named) says in his memoir, Flight: My Life in Mission Control:
Borman agreed to stay suited, but with each passing day, he got more uncomfortable. Spacesuits are bulky and stiff. It takes effort to bend an elbow or a knee, and when something itches, scratching is a real chore. After a few days in the same underwear, I had to assume that scratching was on Borman’s mind a lot.
Finally, human decency and compassion prevailed and Borman and Lovell were allowed to go suitless for a time. No one today expects astronauts to live in their spacesuits, but it would represent a huge advance in mobility and comfort if a suit could be designed with that in mind.
Unfortunately, no one has been able to improve on the adult diaper, or in NASA-speak, the Maximum Absorbency Garment, for waste containment.
How do you tell the astronauts apart at a glance, since they’re all wearing the same big, bulky, white suits? Today’s astronauts always go out in pairs, and if you look closely at the video footage online or on NASA TV, you’ll see that one suit has red stripes on it that can be seen from any angle, thus allowing observers to distinguish between the two. All the suits are white partly so that they absorb less heat, and partly because that is the most visible colour against the blackness of space.
Generally the astronauts stay tethered to a vehicle or platform. However, ISS-era spacesuits can have the capability to manoeuvre independently via small gas thrusters in the SAFER (Simplified Aid for EVA Rescue, illustrating NASA’s charming habit of including an acronym in an acronym) backpack—yet another element making that backpack large and unwieldly.
The complications multiply ad infinitum. And that’s just for spacewalking. Once you get to a planetary surface, there’s also dust (and lunar dust is much more corrosive and harder to get rid of than terrestrial dust) and other contaminants to contend with. Plus, a spacesuit is just one small aspect of a vastly complicated overall mission, each element of which is equally tricky and equally mission critical. Sometimes the wonder is not that we haven’t gotten farther with human space exploration, but that we ever got off the ground in the first place.
It may look effortless to float in space. But before the spacesuit launches, immense amounts of thought and toil are put into every aspect of the design. And even after all that, inside the suit the astronaut is working hard to complete even the most basic tasks in a less-than-ideally-comfortable environment. Still, there’s no question that it’s been worth it. On the one hand, rumour has it that they make great hiding places to smuggle booze onto the International Space Station (a bottle of vodka in a suit arm, for instance). On a more sublime note, remember Ed White, the first American to spacewalk. It took all of Mission Control and commander Jack McDivitt’s cajoling to get him to come back inside. After considerable stalling, he described returning to the spacecraft: “This is the saddest moment of my life.”
Being able to float among the stars is a dream well worth reaching for.
Karen Burnham is an engineer at NASA’s Johnson Space Center, specializing in electromagnetic interference and compatibility (EMI/EMC). She has degrees in both physics and electrical engineering. As an avocation she is a reviewer and scholar of science fiction, publishing reviews in Strange Horizons and SFSignal and articles in the New York Review of Science Fiction and Clarkesworld magazine. She is currently the editor of the blog for the Locus magazine website.
Filed under: Space
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