EPISODE 20: EXPLORATION SPACESUIT DESIGN

Transcript

Jesse Buffington: I think that spacesuits are the most intimate connection between human and machine in spaceflight, and they put the human as close to the space environment as possible.

The challenge in spacesuit design and development, one of the things that I find is fascinating, is designing for all of those extremes in a package that is still common across all those different people.

I think we are ready to have a pretty fantastic capability on the surface of the Moon and out towards Mars.

Deana Nunley (Host): You’re listening to Small Steps, Giant Leaps – a NASA APPEL Knowledge Services podcast featuring interviews and stories, tapping into project experiences in order to unravel lessons learned, identify best practices and discover novel ideas.

I’m Deana Nunley.

We’re wrapping up a three-part series on the design of new spacesuits for future missions. Today, we’re discussing advanced spacesuits for extravehicular activity, or EVA, on the Moon and Mars. This includes the Exploration Extravehicular Mobility Unit, or xEMU. Our guest is Jesse Buffington, the Exploration EVA System Development Lead at NASA’s Johnson Space Center.

Jesse, thank you for joining us on the podcast.

Buffington: Yeah. Thanks for having me.

Host: What’s your role with spacesuit design?

Buffington: My role is called the Exploration EVA System Development Lead, which is really just focused on working across several project teams, each of which are focused on a component or an assembly of the Exploration EVA system. That includes the spacesuit, which is a project and is the vast majority of our focus. We also have EVA tools and interface hardware that connect the spacesuit to the spacecraft. So, my job looks across those and works to help each of those project managers be successful in terms of coordinating their schedule, their budget resources, their technical content, in a way where all those individual projects create together a capability that we can use for spacewalks beyond low-Earth orbit.

Host: What’s the status of spacesuit design for Moon missions and Mars travel?

Buffington: We have a very mature design that is compatible with low Earth orbit, cislunar space, the lunar surface, and even deep space, out to Mars’ orbit. There are some known challenges for Mars’ surface. Mars has an atmosphere, and though it’s very thin, it’s still enough to matter. That atmosphere is made primarily of carbon dioxide. It also just so happens that that atmosphere poses challenges for thermal control and carbon dioxide removal from the suit.

We have options for those, and the xEMU is designed to be upgraded and evolved over time. So, today, we have an opportunity to create a spacesuit system that can work for our portion of the solar system, so to speak, a significant portion, that I think we are ready to have a pretty fantastic capability on the surface of the Moon and out towards Mars.

Host: Could you talk with us about some of the key features and components of the xEMU?

Buffington: Sure. There are quite a few, but at a high level, I’ll name three that really come to mind. First of all is the sizing range. The xEMU is designed to include a much broader size range of astronauts, with a particular emphasis on the smaller size. We really, really are trying to design for smaller stature female crew members and be inclusive of their body sizes. We think that if we can do that effectively, which our early prototypes are showing a lot of promise on, then we will definitely be able to facilitate fitting of much larger personnel as well.

Then next, in that same vein is what we call the rear entry upper torso. So, the top half of the suit, the part that wraps around the wearer’s chest and shoulders, that is designed to ease the don/doff process and improve our mobility. So, literally, the back of the suit, where the life support backpack is found, it is actually a door that is hung on a set of hinges, and it opens and allows the occupant to climb in or reverse out. There’s been a lot of work done to understand the different ways spacesuits may increase the likelihood of injury to the occupant, and the xEMU design incorporates everything we know today to reduce that likelihood.

Then the last thing that comes to mind is the modularity of the life support system itself. It’s designed to lower the barriers to evolving the technology’s components inside the package. We’ve taken great pains to ensure that the design is modular in nature, so that each of the piece parts can be taken out and replaced over time as newer technologies with greater performance or greater safety or a lower cost of manufacture and production, or any other attribute that becomes desirable, we want those components to be relatively easy to swap in and out. So those three things really, I think, speak to a generational improvement in the design of the spacesuit.

Host: So, these components and features that you’re talking about, are those generally considered to be different from the spacesuits that were used on shuttle or the International Space Station?

Buffington: I like to think of it as a family tree. They’re all related and the suits that have come before and up to the present day have helped teach us and have helped us learn. So, they are kind of the best-ofs, the lessons learned, both things that work really well and things that we realized we can do better on, but they are definitely intended to be different from our prior suits. We’re trying to take, as I said, kind of the best-ofs from each one and the lessons learned from each one, and create a whole new assembly that really incorporates several decades of development.

For example, in the Apollo Program, the suits that the crew members wore, they had fairly limited mobility, and that’s what leads to what we call bunny hopping or, as you probably have seen on videos of the Apollo lunar surface EVAs, the crew members kind of hopped across the surface. That was actually compensating for the limited mobility of the pants, the lower torso assembly of the suit. So, our design is well informed by several decades of various teams across the country studying how a much more mobile lower torso might help you. So, we intend to incorporate that and it will be, I believe, the first flight spacesuit that we’ll have actually incorporated that increased lower torso mobility.

You can also point to some other things in the design of both the life support system and other components of the suit that are just notably different. One thing that really comes to mind is the nature of the CO2 removal system. Up to this point in time, most of the spacesuits have utilized CO2 removal systems that essentially absorb the carbon dioxide during the EVA, and then the cartridge itself, for lack of a better term, is either disposed of at the end of the EVA, as if it’s been consumed, or, in some cases, including the current one that we use on the International Space Station, it is regenerable, but it requires an oven that is back inside the spacecraft. We take that cartridge out. We place it in the oven, and we basically bake it off. The increased temperature drives off the absorbed carbon dioxide.

So, what we’re going for today is a CO2 removal system that is actually regenerated during the EVA, while the astronaut is using it, and it actually is regenerated using the vacuum of space. That vacuum allows the cartridge to desorb the carbon dioxide that it picked up, and it cycles back and forth between exposure to the ventilation loop of the suit itself and the vacuum of space, in a way that’s safe and ensures that the crew member is never exposed to the vacuum, but it also dramatically reduces the amount of infrastructure and power that have to be brought along with the spacesuit in the form of that oven that’s no longer required.

Host: It’s so interesting. And I want to circle back to what you were talking about as far as the difference in the mobility. What can we expect for future missions? You say it won’t look like what we saw in the Apollo days. What will it look like when we see astronauts walking on the surface of the Moon again or walking on Mars?

Buffington: That’s a great question. It probably won’t look quite as sleek as what we typically see in movies. One of the challenges with spacesuit development is the thermal environment. So, the most effective way that we have today of balancing the thermal extremes of either the vacuum of, say, the lunar surface or the partial atmosphere, the carbon dioxide atmosphere of the surface of Mars is to use insulation. That insulation tends to add the appearance of bulk and volume. So, we typically find that those suits – now they’re going to look puffier than what you’re typically going to see in a stylized production, I’ll call it.

The other thing is I think mechanically the crew members themselves, they’re carrying the weight of the suit and they’re negotiating what can be fairly aggressive terrain. So, when we think about and visualize the crew members walking across, say, the surface of the Moon or the surface of Mars, I think much of their activity is very intentional about managing their mobility and their interaction with that terrain, as they navigate rough surfaces and inclines. I think every step of the way, they are certainly following their training and thinking about how to manage the mass and the center of gravity of the suit itself, thinking in our lifetimes that will be a required effort. It will definitely take focus on the crew member’s behalf to manage their mobility and to make sure that they are staying ahead of the suit, so to speak.

It’s not inconceivable that as technologies improve and evolve, we can further reduce the mobility limitations and the on-back mass and corresponding center of gravity, to the point where the suit itself becomes less and less of a feature of the crew member’s mobility and almost an afterthought. But I think that’s still quite a ways off for us today, based upon the technologies that are available to us.

Host: How are you testing and demonstrating the spacesuit configuration?

Buffington: We use a spectrum of test facilities, starting with what we call unpressurized or shirtsleeve labs, where the team works with individual components. We also have component-level test facilities with vacuum and thermal capabilities, so small-scale vacuum chambers, for example. Those kinds of test stands and test chambers allow us to examine and prove out that each individual component, like a fan or a pump or an individual part, is performing as expected.

From there, we can go into higher and higher levels of assembly, including test labs where we fully assemble and pressurize the suit in a place that allows us to simulate, say, different gravitational environments. Many folks are familiar with the Neutral Buoyancy Lab, or NBL. That’s the large pool where we can weigh out the suit to simulate partial gravity and microgravity. It’s very similar in concept to a scuba diver that adjusts their buoyancy compensator device, so that they are either neutral or a little bit positive or a little bit negative in the water column. We can do the same thing with the suit.

We also have a system called ARGOS. It’s similar to an overhead crane. That supports the suit and follows the crewmember around. So, you can dial in the amount of weight of the suit that the crane itself is lifting off of the shoulders of the crew member, and you can get them adjusted to the point where they’re essentially free floating, as if they were in microgravity, on, say, space station or in cislunar space on the Gateway or, if they were in partial gravity, we can adjust just how much of the weight they feel, such that they can get the equivalent effect of, say, the lunar surface or of Mars’ surface.

Last, there’s full-sized thermal vacuum chambers. That’s the last and highest fidelity on the ground. Those kinds of chambers have airlocks and are developed with safety systems, such that we can send an astronaut through an airlock and into the large inner volume of the vacuum chamber. We can simulate the temperature and pressure of the spaceflight environment, and provide the crew member different tools and samples to interact with. Those kinds of tests have been used in essentially every spacesuit development effort, and we expect to use it again for the xEMU.

And then last, and perhaps most importantly, from a test facility perspective, we have the International Space Station. No one facility on the ground can fully replace the environment of space with all the features and all the different environmental variables all at once. So, for us, the International Space Station provides the best possible test environment of a new EVA system.

One of the points of art, I think, is how we can combine the data from a test on ISS in microgravity to similar data and similar tests done in 1g on Earth, and together we can have a very, very high confidence that we’ve enveloped the range of environmental features that the suit will experience on the Moon and on Mars. In that way, we actually don’t necessarily have to test at each individual gravitational level. When you test at the high end on Earth’s surface and the low end on ISS in low-Earth orbit, you’ve really kind of bracketed the extremes from a gravitational perspective. Then we can use those other facilities to simulate things like temperature and pressure and the other environmental extremes.

Host: And as you’re talking about simulations and testing, are there technology gaps that are getting your attention?

Buffington: Absolutely. So, there’s an ever-present need to reduce weight. So, material science technologies are always of interest to us. Anything that we can use to further reduce the mass of the spacesuit itself and the components that make it up is always advantageous.

Another thing that really comes to my mind a lot is Mars surface CO2 removal. The technologies that we have today are fantastic, in that they are regenerable either by vacuum or by, say, a thermal profile such as an oven or a thermally driven amine bed. But the challenge there is that you don’t want to take the mass of a bake-off oven with you to Mars’ surface if you can help it. At the same time, the vacuum regenerable carbon dioxide removal systems, they will struggle with the existing partial pressure of CO2 that’s present on the surface of Mars.

So, we have concepts and solutions that address those issues, but those are definitely areas where we can benefit from some additional technology development.

Host: When you talk about spacesuit technologies, how do smart strategies and wise investments help raise technology readiness?

Buffington: One of the things that we’ve tried to clear our mind and think very pointedly about is the common physics that are overlapping between the various credible destinations that human beings will likely be able to do spacewalks, say, in the next several decades. When we look at the solar system and the range of options that are possible, given the propulsion technologies and mission durations, you can actually start to bound the problem in a way where there are some very common themes.

For instance, I don’t think that it’s credible, in my lifetime, to expect a human being to do an EVA on the surface of Venus. The environment is just so harsh, so inhospitable that that’s just really not a problem worth solving. Likewise, it’s unlikely that we would, at this point in time, fly a human mission beyond the asteroid belt, again, within the next several decades.

So, what that starts to do for you is allow you to draw some least common denominators between the different destinations, say between the orbit of Venus and the orbit of Mars, and the different activities that you might do. The human being is the common factor that unifies those different possible destinations together. No matter which location you’re at, the human being has got a certain amount of strength and mobility and dexterity. Also, when you think about it, just the practical length of a workday when the crew member is out EVA.

So, when you start to compare those things and boil things down to the fundamental physics involved, you can find places where addressing issues, say, that you know you have for cislunar space on the lunar surface, also close technology gaps for deep space transit and EVAs, say, in the orbit of Mars or on the moons of Mars. So, I think there are definitely smart strategies that help you prioritize investments, and I think it comes down to thinking about the solar system in a way where you’re trying to establish a capability that’s not hyper-localized to one specific destination. Since the physics is generally consistent across the handful of credible destinations, you can think more broadly than that, and I think that allows your investment strategy to not be necessarily so singularly driven that you hyper-design towards that one place and then have to start over again when you make a relatively minor change.

Host: You’re working an ambitious schedule. How are you managing schedule and risk?

Buffington: This is a really important question, and it’s one where I spend a tremendous amount of my time. Schedule and risk are what drive us in many ways. We need the pressure of schedule to bring that focus and that discernment of making decisions and moving forward. At the same time, we must balance risk and understand our risks in a way where we make those decisions and we’re not so overdriven by schedule that we make unacceptable compromises.

So, at the nuts and bolts level, there are really practical things that we do. There are tools that help us in terms of documenting all of our tasks, describing the relationships between them, estimating the durations, and working that out across dozens and dozens of team members and then project teams and then whole programs, such that we can see what we call the integrated master schedule and what many folks in the industry refer to as its critical path.

Many times risks come down to understanding that critical path and the inflection points — things that if they manifest issues, if they occur, will change the nature of that critical path. So, when we look at the critical path of the schedule itself and the different choices that we have, one of the lenses that we’re going to look through is does this make that schedule longer or shorter, and does it change our likelihood or expectation of a failure and negative consequences?

So, balancing risk and schedule is vital, and it’s one where it really actually encourages us to think holistically. That’s one of the reasons I love project and program management, is that some of the most incredible thinkers I’ve seen in and around human spaceflight were folks that could hold in their heads both the technical and the schedule and the financial, and boil it up to a level where they could make risk-informed decisions that were not necessarily constrained to any one discipline or point of view, but that balance the entire spectrum, and I really appreciate now and understand what it means to have senior leaders that are so thoughtful about every aspect of their programs and the decisions that they face every day.

Host: What is industry’s role in future spacesuit design?

Buffington: It’s extensive. Today, industry is already heavily involved in the xEMU. The vast majority of our components are supplied by commercial companies. We have dozens of contracts across the United States, with companies involved of all different sizes. We also have a growing cadre of experts that have developed relationships with those suppliers and their suppliers’ suppliers. So, if you think about it from an economics perspective, each of the companies that works directly with NASA, say they’re shipping a part to us, they have their own suppliers that they went to, to get lower and lower and lower level pieces. So, we expect a flourishing of industry, and we’re certainly trying to lower the barriers to entry, so that more and more competitors can be involved.

We also think that over time, as we transition the production, manufacturing and sustaining of the xEMU fleet to industry, we hope to see non-NASA users of the xEMU design or its derivatives. We want to see industry find and open new marketplaces, so that spacewalks are no longer something that is the inherent workspace of the government. We think that just like satellite launches, cargo launches, and the emerging opportunities for commercial spaceflight of human beings themselves, we think that there will come a day where people are living and working in space, and they’re doing jobs that are not necessarily for NASA or for the government, but they’re for private entities or for-profit entities that have a need for that.

Host: How do individual astronauts’ personal preferences or tendencies factor into spacesuit design?

Buffington: They’re very important. I think that spacesuits are the most intimate connection between human and machine in spaceflight, and they put the human as close to the space environment as possible. So, every person is different, and yet, somehow you have to still create a suit design that envelopes the vast majority of those differences, in a way that can still be comfortable, can still facilitate the mission, facilitate the work that the crew member is doing, and not necessarily preclude or exclude persons from being involved and from using that suit.

So, individuals always have unique preferences, and many times what we do is we look for trends across multiple individuals. We typically use what’s called Crew Consensus Reports, where we bring in a statistically significant number of crew members. We have them run different tests and evaluations with us, and we look for common threads, where multiple crew members are, say, picking on the same issue or are accentuating the same capability. In that way, we can try to understand what’s really driving the operator. What’s really driving the suit user, and how is it either helping or hindering them?

Host: When you look at suit capabilities that may help or hinder, you’re also considering a crew member’s personal preferences or tendencies – say, for instance, temperature preferences. Some people get hot, some people get cold. Could you talk more about how your work involves accommodating personal preferences inside the spacesuit, especially with extravehicular activity, and how that matters?

Buffington: Absolutely. That’s one of the things that I personally find is quite fascinating. If you think of all the people you know, all the people that you work with, your family members, friends, every person is quite a unique combination of preferences and fundamental physical features. Some people prefer to be a little warmer. You know, the office thermostat is usually a subject of lots of debate. So, between temperature settings and, say, humidity preferences, which is another good one – some people really love the Deep South, the Texas and Houston humidity, although I’m not sure how many people truly love that. There are also folks that just really prefer the low humidity regions of, say, the high desert, Arizona, Tucson, wonderful places just given that low, low humidity.

Well, different spacesuits and different spacesuit designs accommodate those personal preferences and those fundamental physiological needs. There are other factors at play, too. Some people, they sweat a lot. At a given temperature, one person may sweat more than another. Their perspiration is just higher. Frankly, there are also the challenges associated with other metabolic processes. Some people urinate more frequently than, say, others.

So, the challenge in spacesuit design and development, one of the things that I find is fascinating, is designing for all of those extremes in a package that is still common across all those different people. What you don’t want to do is try to design a life support system that is unique to each individual. That would be incredibly expensive, difficult to sustain and maintain that fleet, and just quite impractical. So, you’re trying to build a generic life support system that envelopes all those different metabolic and physiological differences and across those extremes, but do so in a way that is still as slimmed down and as efficiently packaged as possible.

You get into other kinds of preferences in the pressure garment itself, the portion of the suit that the crew members are literally moving in and causing to rotate and move as they do their task work. So, there are places where that can be a rather generic fit, say the lower leg. The primary difference there is just the length of it, for just the different stature of crew members. But things like gloves can be such a close and sensitive fit that the difference of just millimeters can be the difference between success and failure for a given crew member, if they’re out on an EVA with a very hand-intensive task. So, gloves, we have yet to find a way to produce a generic glove that is good for long duration EVAs, and doesn’t lead to challenges with the crew member’s comfort and even, in some cases, hand injuries. So that’s why today we still work towards essentially a custom glove sizing scheme, even though other parts of the spacesuit can be very generic.

Host: When you’re designing a spacesuit, how do you strike a balance between safety and the human drive to explore and experience the space environment?

Buffington: I think in many ways that is the name of the game. Exploration is a choice. It is, I think, both a choice and a fundamental feature of human nature. So, we are driven to do it. You could argue that that’s part of what has made us successful and enabled us as a species to build the world and the way we’ve changed the world around us that we inhabit today. We’ve taken what was available to us and we’ve adapted it and we’ve changed it, and we’ve continued to refine it and understand it.

When we think about spacesuits, there’s a unique contradiction there. The spacesuit is a built device that the person inhabits, and that device allows them to go experience the space environment as close as humanly possible, and to explore regions that they otherwise would not be able to survive in.

So just like, say, equipment designed to facilitate trips through Antarctica or dives in truly deep water, the equipment itself is facilitating that human drive to go understand something that’s beyond the inherent human body’s capabilities. But we can use our understanding of the world around us to expand our own capability and bring that machine in, in a way that really helps the crew member achieve an experience that otherwise they would never have been able to.

I find that fascinating because, as you point out, there is a balance to strike there with the ability to explore and the fundamental need to be safe, to be confident that that crew member can conduct that EVA, can learn those things, and bring that knowledge back. There is a vital role in ensuring that the suit itself is protecting the crew member to the greatest degree possible.

So, when we talk about that design work, it comes down to, I think, understanding what is sufficient. What is good enough? There’s always an idea. The moment we study a given technology or pick a given design solution, the mind can immediately grasp and typically sees what could be done next, what more could be done to improve it. In a beautiful way, there seems to be, in some cases, no end to how much more we could do. But I think many times, being safe is about responsibly deciding when you’ve gone far enough, and when you’ve picked a design solution and a technology that you understand well enough that you can confidently build it and use it, and responsibly embrace it, and that you actually know it will help you do those new and innovative things out there on the edge of human experience.

I think the other thing is patience. So, when you make those choices, in some ways you’re willfully choosing to say, “I know of other things perhaps I could do, but it’s not time. I’m not ready to do those things. I’m already making tremendous progress.” I think being ready to utilize what we know can be safe, learn all the new things that it will enable us to learn, and being open to that new knowledge that comes in, you’ll find, I think, that the next step, the next design is one that will be even more broadly created. When we step too far, when we get too self-assured, I think we set ourselves up for humbling experiences that are just the penalty, the price we pay when we’ve gotten ahead of ourselves.

Host: Very interesting. We really do appreciate you taking time to talk with us today, Jesse.

Buffington: Absolutely. It’s been a pleasure.

Host: Is there anything that we haven’t covered that you’d want to address before we go?

Buffington: I think that what we’ve had time for today is just a taste of the challenge that’s available. So, I would encourage anybody that’s listening, if they’re curious, if they’re interested, NASA needs all of the bright minds and motivated team members that it can get. So, as people think about their daily lives, like what they study, whether they’re still in school or where they work, we are all a part of this journey.

As we mentioned earlier, exploration and that drive to explore is one of the most persistent and unifying themes across the human experience. So, I think I would just say that for all the folks that are listening, as we move forward, out into the solar system, as we expand our understanding of the world around us, I’d just encourage everybody to recognize that they’re a part of that journey, too, and that every day that goes by, we actually kind of live and understand that we’re living in a world that is so broad, so vast that it’s truly an incredible place.

I think just an appreciation of that and a recognition that we’re all participating in that journey is a pretty profound thing, no matter what you end up spending the day-to-day time that we have. I think engaging in even just the thought of that broad process, that progress that humanity is making together I think is a pretty profound thing, and I would encourage folks to think about that, to embrace it as something that they’re personally a part of.

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