It’s no secret that astronauts couldn’t survive the harsh environment of space without their suits. But there are plenty of things you might not know about how these suits go from concept to prototype to the final frontier. We asked Lindsay Aitchison, Space Suit Engineer at the Advanced Space Suit Design Group at NASA’s Johnson Space Center, to walk us through the process.
1. Designing space suits requires a particular set of skills.
And they’re not necessarily the ones you might think. Aitchison says the job requires both critical thinking and creativity. “You need to be detail-oriented and come up with a very precise test plan, ” she says. “When you’re working with human test subjects, you have to design a test where you get constructive feedback on things that are squishy subjects, like comfort. How do you define comfort? You have to think about it from an engineering standpoint and engineer a suit to be comfortable.” Thinking creatively, Aitchison says, allows her to see how technologies from different fields might be incorporated into space suit design.
2. Suits are crafted for their missions.
When creating a new suit, Aitchison says NASA’s engineers must answer two questions to help them determine the structure of the suit: Where are you going and what are you doing?
The engineers start with where the astronaut is going, which falls into two categories: A micro-gravity location or a planetary environment, where they’ll have to walk (which determines how much mobility they’ll need in their suit). The engineers also consider things like how high radiation might be, the temperature ranges an astronaut will experience, and the risks of micro-meteoroids.
Next, engineers have to think about what astronauts will be doing on their missions: Will they be walking on their hands, as they would in micro-gravity, or walking on their feet, as they would on a planetary surface? Will they be digging with tools, or carrying everything on a toolbelt and performing tasks with their upper body? Will they need to be autonomous? “If you're on a planetary surface, that's pretty far from earth, so we're trying to develop more technologies so that you do autonomously EVAs, ” Aitchison says, “whereas [on] space stations, you have a lot more direct contact with the flight control team, so we can offload some of those informatics and rely on flight control to help us.”
3. New Suits Need New Shoes.
EMU suit; photo courtesy of NASA.
The suit most people are familiar with is the Extravehicular Mobility Unit (EMU) suit. Because it's designed for use in micro-gravity—in which astronauts use their hands to move themselves around—to make repairs and modifications to the International Space Station (ISS), telescopes, and more during spacewalks, it needs to have mobility in the shoulders, hands, and arms. "You use the lower area [of the suit] for stability, so that way you have a stable work platform if you're at the end of a robotic arm, " Aitchison says. "If it's too loosey goosey, you can't get any work done."
But new space suits, including the new Z-2, are being designed to go to planetary environments, so Aitchison and other designers spent a lot of time focusing on the design of the waist and hip joints—and the shoes. "This is the first time since Apollo that we need to have a walking boot, and when you're walking in different gravity fields, the way you walk changes, " Aitchison says. "So we're focusing on how to design a boot to work with how you walk in, say, Martian or Lunar gravity environments. It's very different from the EMU, which is just a hard-soled boot."
To figure out what kind of shoe they'd want on their new suits, Aitchison did a number of walking tests with different suits in 2008. "We had [the suits] offloaded to different gravity weights, so if you were walking on a treadmill, it felt like you were walking at 3/8 gravity or 1/6 gravity because [a rig] was holding up the weight of the suit, " she says. The team placed motion capture markers on the lower half of the suit to analyze how the foot, ankle, and hips were moving at different gravities. "We noticed through our testing that people tend to swing their hips up and sort of gallop [in different gravities], so if you pay attention to that, you can figure out where you need to have flexibility versus stiffness in the sole [of the shoe] to make that motion easier."
Though the team is still evaluating designs, Aitchison says that they're currently looking at a hiking boot sole. "It's pretty stiff in the forefoot but it's got some flexibility in the mid foot so you can sort of do those kneeling tasks."
4. The goal is to make new suits lighter.
Apollo suit; photo courtesy of NASA.
The EMU weighs a whopping 300 pounds (the astronauts, of course, don't feel that weight in microgravity). The Apollo suits, including backpacks, weighed 180 pounds on Earth and just 30 pounds on the Moon, by comparison—but, Aitchison says, "they didn't have a lot of mobility to them." The goal for new suits is to make them lighter while maintaining mobility. "When we add mobility, we're talking about adding hard elements like bearings, which make it very easy to work in a pressurized suit but come with a mass penalty, " Aitchison says. "So we're trying to figure out low mass solutions for having those hard elements. We're looking at titanium because that saves us about 30 percent of mass on the bearings when we do that. And then [we're] looking at new types of composite materials for the upper torso material and for the hips and the brief section of the suit."
The new Z-2 will be about 20 pounds lighter than the EMU, "which doesn't seem like much, " Aitchison acknowledges. "But again, we're adding in all the capability of the lower torso that we haven't had before."