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Season 1Episode 336May 17, 2024

Three experts within the Human Physiology, Performance, Protection and Operations Laboratory (H-3PO) at NASA, explain the ins and outs of this integrated laboratory designed to support human spaceflight. HWHAP Episode 336.

Houston We Have a Podcast Ep. 336: H-3PO

Houston We Have a Podcast Episode 336; H-3PO

From Earth orbit to the Moon and Mars, explore the world of human spaceflight with NASA each week on the official podcast of the Johnson Space Center in Houston, Texas. Listen to in-depth conversations with the astronauts, scientists and engineers who make it possible.

On episode 336, three experts within the Human Physiology, Performance, Protection and Operations Laboratory (H-3PO) at NASA, explain the ins and outs of this integrated laboratory designed to support human spaceflight. This episode was recorded on February 23, 2024.

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Host (Leah Cheshier): Houston, we have a podcast! Welcome to the official podcast of the NASA Johnson Space Center, Episode 336, “H-3PO.” I’m Leah Cheshier, and I’ll be your host today. On this podcast, we bring in the experts, scientists, engineers, and astronauts, all to let you know what’s going on in the world of human spaceflight and more. The Human Physiology, Performance, Protection and Operations Laboratory, or H-3PO, is a NASA laboratory within the Biomedical Research and Environmental Sciences Division at Johnson Space Center (now a subset of NASA’s Integrated Human Health Performance Research Laboratories). H-3PO’s work is organized into three distinct technical areas: Exercise Physiology and Countermeasures, Spacesuits and Exploration Operations, and Applied Injury Biomechanics. While the three technical areas correspond approximately to specific functions, laboratories, and projects, H-3PO operates as an integrated laboratory.

Patrick Estep, Nate Newby, and Brian Prejean are leads within the three divisions we’ll discuss today in H-3PO. Their teams focus range from astronaut exercise for preserving crew health and performance, to studying human physiology and performance during spacewalks and protecting crew from injuries during dynamic phases of spaceflight and during suited operations. That’s a lot to cover. What this means is the folks in H-3PO put the “human” in human spaceflight, conducting research, sharing knowledge, and ensuring that spacecraft are ready for human occupants before they launch into space. But to really get into the weeds on everything that H-3PO does, let’s talk with Patrick, Nate, and Brian. Let’s get started.


Host: Patrick, Nate, and Brian, thank you so much for joining us here on Houston We Have a Podcast.

Brian Prejean: Awesome, thanks for having us.

Nate Newby: Yeah, awesome. Thank you.

Patrick Estep: Likewise. Excited.

Host: So, before we get started on talking about what H-3PO is, I want to know a little bit more about each of you, what your backgrounds are. So, what did the start of your NASA journeys look like and how did you get involved with the agency?

Patrick Estep: Yeah, I’ll start. So I’ve got a background in biomedical engineering. I did a lot of work in orthopedic biomechanics before coming here. Worked with the Army, one of the research labs in Alabama looking at a head, neck, and spine injury and kinematics there. I was looking for a job at the time. I actually applied to Nate’s group, and he rejected me.

Nate Newby: Sorry.

Patrick Estep: But shortly after that, they had an opening for a human performance engineer to come in and kind of support different project level engineering and testing on a number of things related to space suited stuff. And so they contacted me back and I happily accepted and have been here for about five and a half years.

Patrick Estep, human performance engineer in the Human Physiology, Performance, Protection & Operations Laboratory at NASA's Johnson Space Center.
Patrick Estep, human performance engineer in the Human Physiology, Performance, Protection & Operations Laboratory at NASA’s Johnson Space Center.

Host: Nice. Nate, how about you?

Nate Newby: Yeah. Good. I was interested in hiring your brother, though. I’m Nate Newby. My undergrad degree is in biomedical engineering. My master’s is in AeroAstro engineering and pretty much fell into this. My advisor at MIT was a former astronaut, and I kind of started doing artificial gravity work, which is spinning people around real fast and getting them sick on centrifuge. And so I started doing that in grad school. There was a project coming down here, this is back in 2002, that’s how old I am, doing centrifuges and kind of the concept of taking gravity with you. And so we built a centrifuge, put it at the University of Texas Medical Branch, tested it out as a countermeasure and started doing that work and simultaneously started getting into exercise and biomechanics modeling. So I started doing exercise work and looking at models of exercise in space and how that loads the body differently than on the ground. And then took a year, went to work at a university in Switzerland, didn’t reach escape velocity, came back, started working occupant protection issues and injury biomechanics. And been doing that basically for about 10 years now.

Host: Wow. That’s impressive. Career and centrifuge reminds me, that always makes me think, you know, sci-fi, science fiction. Space station’s of the future, so that’s pretty cool.

Nate Newby: Right. Yeah. Pretty cool. Space Odyssey. Yep.

Host: Alright. Brian, how about you? How’d you come to NASA?

Brian Prejean: Yeah, it was an interesting, fortuitous journey kind of. My background is in exercise physiology, undergrad in that, and then took some time working in an industry with clients. Patients of all different backgrounds. Knew I wanted to go back to school. So I did and did both of those things and just kind of expanded my focus in the area. Did a little exercise biomechanics in the lab when I was there. And that was in Arlington, Texas, and I knew I wanted to get back down to the Gulf Coast. So that’s what brought me down here. As I was finishing up my dissertation work and starting to look for jobs and things, yeah, kind of fell into place there. They were hiring in H-3PO for stuff in my field. So joined December, 2018 and, you know, really saw how, I guess kind of the breadth of experience that I had gotten across the exercise physiology and assessment realms were really a lot what they were doing here. You know, just applying the same techniques and tools to the crew members. Slight twist on the same context. So, yeah, I’ve been here for five years. It’s been a lot of fun. Glad I get to stick around Texas and the Gulf Coast and apply myself in the field. So, yeah, we’ve been doing a lot more over the past five years. So the growth’s really interesting in the area and excited to see what comes next of it. So I’m not as smart as these guys, but honored every day to get to work with folks from all different diverse backgrounds and apply exercise in this context.

Host: That’s pretty impressive. So I think I love this conversation because I think this is a job people don’t initially think about when they think of working at NASA. Everybody’s mind goes to, you know, an astronaut or if like controller or even a doctor these days. They might think about, but there’s just such an importance of this study here on Earth to help us go farther into space. So you’ve all had a few years now under your belt. Are there any favorite projects that you’ve worked on?

Brian Prejean, Exercise Physiology and Countermeasures lead at NASA’s Johnson Space Center. Credit: NASA
Brian Prejean, Exercise Physiology and Countermeasures lead at NASA’s Johnson Space Center. Credit: NASA

Patrick Estep: Yes. They’re all great in their own right. They’re all frustrating in their own right as well. I think I speak for all of us when I said we work in a really unique challenging environment. We’re working with really high performing individuals, really complex problems and things you wouldn’t normally think about in different research contexts. For me, one of the ones that I am continuously excited about is a lot of the work we’re doing with virtual reality and as it relates to EVA, testing and looking at different sensors and physiologic models and understanding kind of in a lower fidelity research grade environment. How can we test and prepare for actual EVA activities and simulations in higher fidelity environments and translate that out? And then what that ultimately will translate to hopefully for actually in flight use as well, or training of the crew on the ground before flight. And so that’s one that I’m continuously excited about on our realm, but a lot of the great stuff we do support for exploration atmosphere. CHAPEA are two of the other big notable ones that, that my team has taken part in. I’ve been very down and in as well. A lot of suited testing, which is a ton of fun for me. So yes, all the things.

Host: Any other favorites?

Brian Prejean: I love getting involved in Patrick’s projects cause they do all the fun stuff in suits and pressure chambers. Some of the coolest experiences. Just, you know, well, out of this world things that you couldn’t make up if you tried. I’ve been participating in some data collection experiences for the spacesuit and exploration operations, whether that’s in the NBL, just scuba diving with crew members in a suit is something that I don’t know if anybody expects they’ll get a chance to do as part of their work function. I like to geek out over exercise hardware, so it’s, you know, something that’s in directly my area, but also gets to work with a lot of the smart folks, the engineers and stuff, and the development of the different hardware that’s actually going to get to fly. So that’s where I have the most fun. And it’s pretty isolated though, so it’s good to be an integrated lab and get to kind of diversify.

Host: Nate, you’ve been here a little longer. Any other favorites?

Nate Newby: Yeah. I have one that actually fairly recent, just happened last holiday, so not this Christmas, but the one before. I got a call Christmas Eve and they said, you know, the Soyuz that was up on station sprung had a thermal leak and that we were zero fault tolerant to bringing our crew back from the ISS. We had one U.S. crew member on that vehicle and they said, “What can you come up with to try to bring him down if there was something like an ammonia leak or something on station where we had to evacuate?” And so it was my own little kind of Apollo 13 moment without all the stress, you know? But I got to kind of scour around what’s available on the space station, what’s available in Soyuz itself, that we could repurpose all of that, and came up with a plan to put, it was Frank Rubio in the cargo hold of the Dragon space vehicle, and then ran our models and did our assessments and found out that this is something we could rush in and actually set up. And it now is the contingency scenario that if we have something like this again, that we have a kind of a config that we can put, take the cargo off Dragon and put crew members under the seats and bring them home safely. So kind of an interesting, I never want to do it again, but it was a very fun, interesting project.

Brian Prejean: Well, you won’t have to if you did it right.

Nate Newby: Yeah, I hope not. I hope not. Yes.

Nate Newby, Applied Injury and Biomechanics lead at NASA’s Johnson Space Center. Credit: Nate Newby
Nate Newby, Applied Injury and Biomechanics lead at NASA’s Johnson Space Center. Credit: Nate Newby

Host: Yeah. That’s an amazing feat. And I like that you referenced Apollo 13. To be in that room, you know, where it happens and where it’s really being figured out, I feel like is one of those hallmark moments when you feel like, “Wow, I really work at NASA.”

Nate Newby: Right. Yeah. It was very exciting.

Host: So let’s talk about H-3PO as a whole. This is one organization essentially, but it’s really three offices. Can you break that down for us?

Patrick Estep:  Yeah. So H-3PO is the Human Physiology, Performance, Protection and Operations Lab. Within that, we have four separate technical areas. There’s three by way of subject matter. And so I lead the work that’s focused on Spacesuits and Exploration Operations. Really focused on human health and performance, during or as it relates to EVA. And then of course, Nate and Brian also lead the Applied Injury Biomechanics team within the lab, as well as the Exercise Physiology and Countermeasures teams within the lab. We also have what we call kind of a cross-cutting data and software team. We’re doing a lot with sensors and data streams and all sorts of different informatics and analytics. And so that’s kind of a group of really consolidated experts in computer science and data analytics and things like this that kind of support us through all the work that we do and all the data we collect.

So, you could probably speak better to this Nate. But I think the lab started a little over six years ago with the idea and recognition that there is a lot of integration between these groups that I’m sure we’ll dive into here today. From where I sit on the EVA side, there’s a lot of risk and potential for injury or compromised performance due to different biomechanics and postures that the crew may experience during EVA. And so that’s kind of how we intersect very grossly with the applied injury biomechanics group. And then on the exercise side, as we ask these crew members to go out into these, to one work against the suit, to do these different tasks, to traverse along the lunar or Martian surface and to use these heavy tools, you hear these different payloads and things like this, there’s a fitness component to that. You’ve got to be trained and prepared and ready to support all those things. And so how that ties back to the fitness element, both aerobic and strength, and how all of that kind of comes together to support EVA is kind of an important piece. And so there’s a lot of integration. I only really highlighted my piece and I’ll let these guys talk cause I am notorious for taking all the mic time, but—


Patrick Estep: That’s kind of just one quick example of kind of the integration between the groups, I think. So it is a big integrated lab, and I think they used to be three disparate labs or different parts of labs that ultimately came together because there was a recognized need and vision for this level of integration.

Nate Newby: Yeah. I mean, I kind of have been in my career ping pointing back and forth between exercise and injury occupant protection work anyways. So it was kind of the same biomechanical models that you use for developing strength or assessing, you know, the efficacy of exercise on orbit. I can use those same models for occupant protection and then I can also apply those models to spacesuits and spacesuit injury and look at the same sort of things. Those came a little bit later in my career. I think basically once we merged, you know, Patrick does a lot of the performance end of like, how efficiently can we do tasks? Can we get the work done? All of those sorts of things. And then I’m more on the end of, you know, are you going to hurt yourself in any way, you know, in the suit. And so yeah, it was kind of a natural fit for me. I kind of all three groups or three kind of independent groups, but we do a lot of the same work that we can share across the three.

Brian Prejean: Yeah, those are all great words. I don’t have much to add. I think, obviously if the pieces fit together naturally and we’re I think the three of us around the table are risk custodians in our own area. So trying to assess and quantify the risk specific to exercise is kind of impossible without talking to these gentlemen. I think it’s kind of mutually symbiotic in that way. So yeah, a lot of the questions that we’re getting asked in terms of what the risk for especially the upcoming Artemis missions are, we really do need to have that integrated approach.

Host: So I want to back out a little bit and talk about each of these individual components that make up H-3PO And I want to start with exercise physiology and countermeasures. So with astronauts, what kind of medical tests do you run on them to determine how their exercise routines are affecting them?

Brian Prejean: Yeah, that’s a great question. NASA has really a slew of tests that they do to assess changes astronaut health and performance. There’s a set of requirements called the Med B Requirements and Medical Evaluation Document that carries these requirements. So obviously we’re focused on  their fitness and overall, let’s call it aerobic capacity or aerobic fitness and muscular strength and endurance. So there’s a subset of the Med B tests that focus on those. So we work with the Astronaut Strength Conditioning and Rehabilitation Specialist. We call them ASCRs. I’d never have to say that whole thing. But they do really the day-to-day operational training and working with the crew members to make sure that they’re maintaining or improving or recovering their physical conditioning. So we do really a battery of tests like isokinetic, which is just controlling the speed around a single joint to measure the strength or endurance in the muscles around that joint. Or more full body tests, say like a mid-thigh pole where you’re just standing, pulling against a fixed bar and measuring your force output. So some general strength tests like that. And then for assessing aerobic fitness, we typically use the bike to do a, what we call a VO2 peak. So just taking someone to their max endurance until they can’t pedal anymore. And then there’s actually a bike on station where we can compare that test on the ground and in flight. So that’s why we like that modality, but we’re always looking to kind of expand. And now with the upcoming Artemis missions, we’re looking to see can we get those same metrics in the future vehicles cause having that translation between flight and ground is really important. But in general, it’s tests and assessments that you see in the typical clinical setting on Earth or sports performance.

NASA astronaut and Expedition 67 Flight Engineer Bob Hines works out on the Advanced Resistive Exercise Device (ARED) inside the International Space Station's Tranquility module. The ARED mimics the inertial forces generated when lifting free weights on Earth enabling crew members to experience load and maintain muscle strength and mass during a long-term space mission.
NASA astronaut and Expedition 67 Flight Engineer Bob Hines works out on the Advanced Resistive Exercise Device (ARED) inside the International Space Station’s Tranquility module. The ARED mimics the inertial forces generated when lifting free weights on Earth enabling crew members to experience load and maintain muscle strength and mass during a long-term space mission. Credit: NASA

Host: Are these tests that you run on Earth, in space, or both?

Brian Prejean: Both. The strength ones, so the mid-thigh pole that I was describing is common in sports performance assessing just full body strength. And it relates to that lifting, sprinting, jumping, we just finished an effort to verify the feasibility of collecting this metric on the ARED, the resistance device on ISS. So that’s a new strength measure that we have in flight. And the first really well standardized and objective measure that we can use in flight to track those time course changes. So that’s one that we do. And then the cycle aerobic capacity VO2 max. So there’s a metabolic analyzer on station and they use that with the CEVIS and we can repeat the protocols that we have here on ground.

Host: Speaking of the space station, you’ve only been here five years, I say only, but that’s a pretty big accomplishment itself. But we’ve been on the space station for about 23 years now. So what have we learned in that timeframe from these studies that help us prepare for future long duration missions?

Brian Prejean: Yeah, that’s a great question. You know, we’re really having to try to answer that in a lot of different ways these days when it comes to, hey, what do we really need to keep our crew members healthy and fit and performing optimally? I could say in short, we’ve learned a lot, but we still have a whole lot to learn. The difficulty in really making confident interpretations from the data is really the way the data are collected and the amount that we have. It’s all operational. You know, we get what we can, but understand there are other priorities related to the mission that might have to move things around. So we’ve been able to establish a general range of outcomes that we would expect long duration crew members to have after, you know, six months or so, exposure to microgravity. But that’s also with the standard countermeasures they have on ISS. So we’ve been using the current suite of exercise hardware for let’s say about 10 years, depending on which piece you’re talking about. Before that there were other pieces of hardware, they were different maybe they didn’t have all the capabilities that they have now.

Expedition 70 Flight Engineer and NASA astronaut Loral O’Hara exercises on the new teal CEVIS Ergometer aboard the International Space Station. Credit: NASA

So again, in trying to be specific to say, “Okay, if we have X type and amount of exercise be good for the Moon,” we’re definitely not there yet. But we can say that “Okay, from this general approach that we are doing a much better job than we have in the past of protecting the crew members.” I mean, we’re seeing margins of previous decrements in six months flights that were coming out of maybe 30 day or a little bit longer shutter flights. So definitely doing better. Still, most of the crew members are returning with about, on average, and there’s again, a wide range, but on average about 10% losses for the various metrics. It kind of all settles around 10% aerobic capacity, muscular strength, and endurance. Even with the amount of exercise they’re getting on ISS, which is about an hour and a half per day, still on average, some substantial, I would say, notable losses. And so it’s going to be an interesting challenge for a sustainable deep spaceflight to see, okay, what do we need to fit in those vehicles? Will it be enough? Is there anything beyond exercise that we can do to really optimize these outcomes?

Host: Yeah, it really speaks to the importance of the International Space Station and that being a test bed, as we look at long duration flights to the Moon and Mars, right now we’ve got short duration flights planned to the Moon, like Artemis II. So are you guys doing any testing on that mission, specifically?

Brian Prejean: On Artemis II? Yeah, Artemis II is really going to be a kick the tires kind of flight for exercise in a lot of ways. We have a brand new device, it’s called the Orion Flywheel. They’re comparable devices on Earth in the commercial space. So it just uses a spinning mass to provide a load to the user. Pretty simple devices where you just have a strap wound around an axle and you’re changing the momentum of that mass by pulling against it and then trying to slow it down and speed it back up. Kind of like a yo-yo. But we’ve never used anything like that in space before. And so understanding the biomechanics of it, you know, how is the human going to interact with this hardware is a big open question we have, well, for how, how is that going to work in microgravity, I should say, not to mention within the Orion vehicle. So all the ISS hardware is isolated from the vehicle with these vibration and isolation systems. That won’t be the case for the Orion. So yeah, we have a number of questions surrounding how will exercise work on the device and microgravity, how will the vehicle tolerate it from those exercise loads? And then these early missions are relatively short, but eventually how well will the crew members be protected with this kind of approach.

Host: Right. And how do you think exercise will look different on these future lunar and Martian missions? Those longer ones than what we’re used to seeing today on the space station? You know, we’ve got a lot of videos out there of people working out using ARED, using CEVIS, which is the bike. But when you’re talking about the Flywheel, that’s also very compact, which I know is also part of the criteria.

Brian Prejean: Right. So there’s definitely going to be a trade space on what we are able to accomplish within the constraints. So obviously the flywheels within a really constrained environment, and that’s probably going to continue. Our objective is to try to make exercise look the same wherever you are. So ISS has really good capabilities. So the ARED, Advanced Resistive Exercise Device, you can perform pretty much whatever type of resistance exercise you want to do on that machine. And then with a bike and a treadmills, okay, you can get a nice broad approach to exercise. We do want to understand if you need all of that, or if there are important components of it that make the most impact. I’ll hold my biases for now. So it’s going to be that balance of how much can we fit within the constraints to get the most important aspects of the, you know, human movement, human exercise in a functionally relevant manner. So I think just new technologies and motorized units.

The Artemis II crew will exercise on Orion with a flywheel, a simple cable-based device for aerobic exercises like rowing and resistance workouts like squats and deadlifts. It works like a yo-yo, giving astronauts as much load as they put into it, maxing out at 400 pounds. Credit: NASA

Patrick Estep: Yeah, I think Brian is discrediting himself a little bit. There’s a lot of work to do as the paradigm shifts from a very microgravity focused test bed to the exploration. When we effectively add some gravity back into the equation, how is that translating to the exercise countermeasures and the needs and the prescriptions that the crew are going to have to do? And not only that, but we’re effectively adding the lower body back into the equation. As we get ready to go EVA, we’re going to be walking around, unlike the very hand intensive floaty EVAs we’re doing on space station now, which I think is also going to add and contribute some different things in some ways. And whether that’ll be positive or negative, with respect to fitness demands, I think remains to be seen. But I think those are just a couple of the challenges. And this doesn’t even get into the specifics about types of tasks and payloads and motions and all these kinds of things that they may have to interact with. So I think there’s a ton of future work there and kudos to Brian and the team for having to sort all of that out as best we can.

Brian Prejean: No, yeah, thanks for highlighting that cause it’s, again, in a sense and coming from a strictly exercise background, that’s what we would like to replicate again, with the reality that we’re facing, that’s not really possible. So in understanding how best to operate within all of those constraints and really being as surgical and optimizing the countermeasures to the needed performance capabilities is going to be key. And Patrick just touched on really all of the big questions that we’re trying to answer is, okay, well, you’re going to be back in gravity and working in a spacesuit. Sure, it’s just one sixth and maybe the work is kind of low intensity, but do you still need to exercise as much as you do when you’re just hanging out in microgravity? So we do not have that level of information yet, that’s for sure.

Nate Newby: I’m seeing lunar games in the future. Triple jumps, pole vaults.


Host: Sign me up. Put me in, coach.

Brian Prejean: Do the hammer throw.

Nate Newby: Hammer throw. Nice.


Host: Well, thanks so much, Brian. Fascinating. I want to talk a little bit about Spacesuits and Exploration Operations. So you’re not the team that develops the suits themselves, but you work with them and study how the astronauts operate within the suits. How do you do that?

Patrick Estep: We try. No, we don’t develop the suits themselves or the hardware. We try to understand it, but at the end of the day, it is miraculous and incredible a feat of engineering as spacesuits are. I mean, they are effectively personalized spacecraft. We have to remember there’s this like squishy complainy pink bag of flesh that we’re asking to do stuff, and they have feelings and things in there. They have feelings and things, and so we have to take care of them. And so we’re really human-forward in a lot of what we do, and it requires a lot of integration. Understanding what’s the interaction between the human and the spacesuit is one kind of example. Again, looking at the injury biomechanics piece, the spacesuits don’t fit the user perfectly. So you almost kind of have to actuate and work against the suit a little bit, which then has some impact back on the user. That adds some workload, potentially some frustration in some cases and some uniqueness to the joints.

And so not only the human to suit interaction, we also need to understand from the operational perspective what the crew are actually going to be doing. And how that ties again, back to the injury piece, to the performance piece, the exercise piece. If we’re going to ask them to go do certain tasks, we want to understand what’s the cost to the human of doing those things. How hard are they having to work? Is it just physical demand or is it cognitive demand? Is there a teamwork component to this as they’re working with their buddy who’s out there with them or working with the intravehicular crew, or even back to mission control? Or looking towards Mars, how that potentially changes is now we’ve got comm delays to play into this. So really understanding the impacts to the human and then how that can translate back to the hardware. So thinking again about physical workload and looking at things like metabolic rate. If the crew are working really hard on some task like geology or moving or deploying a payload, that requires oxygen that they have to consume and therefore, there’s metabolic consumables associated with that. And so the suit needs to be able to provide that. And we need to be able to plan and juggle EVA timelines and operations such that we’re not going to be blowing through all of our consumables and can still meet all the objectives that we want. So all this to say that EVA and suited research is, it’s a very cool integrated community, and we all do have to work together and understand the implications on the human versus the suit versus the operation versus whatever else may be at play that I haven’t described here.

Host: When you look at tasks that you’re asking an astronaut to do on a spacewalk, we do a lot of things that are not repetitive, but, I mean, yes, things that we’ve done before. When you think about swapping out batteries or installing a new solar array, do you compare previous astronauts’ metabolic data to get an estimate of what you expect the upcoming astronaut to use energy wise? Or is it really pretty variable dependent on the person?

Patrick Estep: It does vary a lot from individual to individual. Some of the data that we are responsible for collecting, Brian described the Med B requirements earlier. Similarly for EVA training, we also collect a lot of this data on the ground for individual crew members before flight. And so once we then know which individual will be performing an upcoming EVA, we can use that same individual’s actual data from their NBL training to say, “Hey, their met rate was this during this task and this during this task.” So on average, you know, they were whatever rate overall. And then against kind of the plan tasks and timelines, recognizing that one, there’s a translation between, Earth-based testing and then microgravity. Obviously, we don’t have to work as hard when we’re not fighting gravity or water drag in the NBL or whatever. There’s a piece of that that plays into it as well. But we can do that on an individual basis, which is really super cool. And we do a lot of that for ISS now, and we expect and hope and are working towards developing those same capabilities and pipelines for exploration, but potentially expanding on that. So we’re not just looking at metabolic rate, but we can look at things like heart rate, thermal load and burden. Again, cognitive workload fatigue is going to be an interesting one. The exploration conops right now are saying we can maybe do up to four EVAs in five days, which is a radical uptick in tempo from what we do on station now, which is hand wavy one EVA a month or something like that. And so, all of the things that the crew are having to do to prepare for EVA and do all of their other things that they’re going to have to do and kind of the exploration architecture around that, are they going to have sleep impacts or are they going to be working so hard that they’re just fatigue and is there cumulative effect?  And so coming up with ways to collect those data and understand how those may translate from ground training to eventually flight during Artemis or beyond is stuff we’re working on now.

A test subject is pictured simulating a Martian EVA using virtual reality (VR) as part of the PersEIDS test. H-3PO uses this test to gather bioinformatic information such as heartrate and oxygenation levels while the user performs space walks on a simulated Martian surface. The user is walking on 360-degree treadmill while wearing a VR headset for full immersion. Credit: NASA
A test subject is pictured simulating a Martian EVA using virtual reality (VR) as part of the PersEIDS test. H-3PO uses this test to gather bioinformatic information such as heartrate and oxygenation levels while the user performs space walks on a simulated Martian surface. The user is walking on 360-degree treadmill while wearing a VR headset for full immersion. Credit: NASA

Host:  You talked a little bit about the suits and how astronauts sometimes have to work against them. What are some of the successful mitigations you’ve developed to ensure the success of spacewalks?

Patrick Estep: Yeah, so I think by way of having to, I’ll say fight the suit, there’s not a lot we can do with respect to physical workload. I think a lot of times it’s really just individuals getting into the suit and getting that familiarity and understanding what’s the difference between this suit versus that suit versus that suit and this environment versus that one versus that one. And understanding what works for them, what’s comfortable for them, within the safety and, and requirements of different things that they have to do. I think one thing that Nate’s group has really pioneered over the last handful of years is collecting data that are really focused on the suited exposure. What kind of things did the user experience kind of before as they were coming into a suited event and after, did they have any hotspots or did they experience anything that was a negative experience kind of as part of that environment? And then if there’s ways that we can either adjust some of the suit sizing a little bit in some ways or it’s something that we can keep an eye on or train against, I think those are some ways where we can kind of mitigate some of the different kinds of decrements and things that we’re seeing there.

Nate Newby: Yeah, I’ll just add in one of the other things, and I always forget what this acronym means, SERPO it’s work hardening basically.

Patrick Estep: Surface EVA Readiness and Performance Optimization.

Nate Newby: Thank you so much. So if we understand the demands that certain tasks and certain EVAs put on, say, crew, maybe a certain thing requires a certain amount of low back strength. For example, we can turn to the exercise trainers and say, “Hey, this is a task that’s going to put strain on our crew members. This is what it looks like, and can you train, come up with a training regimen, a training program that will harden our crew members to the work?” So it’s a potential mitigation that we can look at for helping our crew with difficult tasks in the suit.

Brian Prejean: Yeah, I’m glad you brought that up. I was gone plug the ASCRs in the MSK team as well. So MSK stand for musculo-skeletal, it’s the acronym referring to this group on the medical operational support side. So as Nate was mentioning, if they know what the problem is with the individual crew members, say within the suit, and they can develop directed interventions for their physical training or rehabilitation and recovery, they’re good at rehabilitating people in flight too, if needs arise.

Nate Newby: I’ll say too, the suit can help you, so you can recruit the mass of the suit to help push something like you can use it. So, and you can teach those kind of things too through ergonomics or whatever that you know, that to take what advantages you can get when you’re suited and use them to the best advantage possible.

Host: We are developing some new spacesuits for use on the space station, but of course also future lunar use. Have you been working with those?

Patrick Estep: We would love to. I can’t speak too much to the things that are going on there, but ultimately, as those get transitioned to NASA operations, a lot of the same things that we’ve kind of described here by way of data collection and understanding the suited user interaction, we definitely need to figure out and work through and characterize and understand.

Host: Those new suits are being developed with commercial partners, which we see a lot with NASA programs right now. What’s it been like and have you worked with commercial partners as they’re doing this development process and providing kind of the NASA insight?

Patrick Estep: Yeah, there’s definitely been a lot of insight. It’s been a unique challenge trying to, I think, transfer all of the knowledge that NASA has across this whole domain and all of the different subject matter experts out there, and trying to figure out how to meaningfully translate that into design requirements or verification and validation tests to prove that the new suits are going to be able to do all the things that we need them to do to support exploration operations. So it takes, I think an army would be almost an understatement. It seems like everybody and their brother has contributed at this point, but I think that’s the level of knowledge that that is available, and that’s the level of knowledge that’s needed to support a lot of that as well. So it’s definitely been unique and trying to keep it all agnostic as well and separate because they are two different providers for the suits. And same thing with a lot of the vehicles as well. People don’t think about that so much, but there is the interaction between the vehicle and the suit. Looking at something like decompression sickness and mitigation, we leverage the habitable atmosphere as well as, as well as the suit atmosphere to try to remove that risk from EVA because of the pressure transition from your habitat to the lower pressure suit. And so that’s one example where there’s got to be some interplay between these different providers as well. And so trying to get all of, not only internally, but externally, getting all of those providers to work together and talk together and understand how all of their things fit in the architecture and how that supports the ultimate mission is an ongoing set of discussions and challenges.

Host: Well, thanks so much. Did you want to add anything else about Spacesuit and Exploration Ops?

Patrick Estep: No. I’ll just say it is an incredible time to be at NASA and in the wake and in preparation of not only things that we’ve done historically looking back to the Apollo program, but how that’s transitioning into Artemis, and eventually Martian exploration and well, and just working to figure out how to support EVA and the missions that we’re going to do for all the reasons and objectives that NASA is interested in is super cool and exciting. And we’re so fortunate to be like right in the middle of it looking at and working with the individuals, but also the amazing population community within it. So, no, I think that’s it.

Host: Well, thanks so much. And Nate, it’s your turn. We are going to talk Applied Injury Biomechanics. Your team works with our Orion spacecraft, Boeing’s Starliner and SpaceX’s Dragon. And this is all to ensure the astronauts are safe during the most dynamic portions of flight. Of course, this is launch essentially any of the major burns or maneuvers in space, potential aborts or landings. And of course, splashdowns, we have those too. So there are three spacecraft right now, and this has to be a really busy era for your office, right?

Nate Newby: Super busy. And actually, if you include Soyuz, you know, that’s four. So I’m a principal investigator on a study on Soyuz where we track all the landings and all the injuries that happen to our crew when they land in the Soyuz vehicle. In addition to that, we got two vehicles that are going to land on the Moon, right? Or potentially, we got SpaceX and Blue Origin developing vehicles for that. We got rovers, pressurized rovers, pressurized rovers. So, you know, this is a part where we apply occupant protection stuff too as well. We got, you know, the Gateway space station. We got the commercial platforms, and so our group has, we’re like requirement owners, requirement integrators, for how much acceleration crew can take, how much vibration, rotation, impact loads, all of those. So we track all of those kind of requirements on all these programs. So it’s super busy, but as Patrick was saying, super exciting. Like, you know, most engineers in the history of NASA are lucky to be in the development of one vehicle, right? For their whole career. And here we get multiple vehicles and the suits. So I have the same kind of requirements in the suits. And so, in the last five to 10 years, I have learned a ton. You know, being in and seeing all the different ways and creative ways that you can get to space station, you know, land on the Moon, develop suits, all this stuff has been a huge learning opportunity for me and a super, super exciting time to be here and working at NASA.

Host: Everybody’s nodding their heads. We all agree. This is literally the most exciting time, I think, to be working here with all of these spacecraft flying, with Artemis on the horizon. And you were talking about injuries and, you know, looking at injuries during these dynamic phases flight, but without putting an astronaut in these scenarios, how do you model that? How do you figure out what they might be exposed to and how their body would react? And I know we have some of that data because we are flying some of these spacecraft, but when we think about Orion, and any future lunar landers, what’s that look like?

Nate Newby:  Yeah. We do a ton of work before we ever put a human in the sea and launch them. I was involved pretty intimately with the certification for the crew Dragon and the Demo-2 mission to start with humans on that vehicle. And we really start with the providers. They give us the whole range of dynamics that the crew can be exposed to. And that can be on the launch, it can be a launch of board, it can be, you know, rendezvous, docking, return, you know, the whole return burn and landing, you know, either on land or in the water. And then we take those dynamics, and we do tests with crash dummies, so, or Anthropometric Test Devices, ATDs. And so we use the Air Force Research Laboratory facility up at Wright-Pat Air Force base, and we’d pick driving cases out of those loads, and we run impact tests with these crash dummies, and we put them in the flight seat, we put them in the flight helmet, flight suit, flight restraints, and we did a lot of years of research tying injury metrics to these crash dummies. You know, the crash dummies were built for the automotive world and largely tuned to frontal impact, you know, kind of crashes. Our environment’s quite different, you know, we got spinal and we got potential lateral, and so we have different loading directions. We have different loading magnitudes. And so we did a lot of work to tie injury thresholds. So when we do these tests, we see whether or not the, they, they met the kind of requirements that we’ve put on these vehicles. And further we tune finite element models of these dummies to the test themselves. And then we run simulations of the whole range of dynamics that the crew can be exposed to. And we compare that against the requirements that we set for.

Then we validate all of that work in full vehicle drop tests. So we’ll take the full vehicle, we’ll put the crash dummies in it and drop it in real world kind of conditions. And we do this at NASA Langley, they have a big pool out there. If it’s a splashdown landing, we launch them into the pool. If it’s on a land landing, we drop them on land. And, you know, we make, take our model that we think  is well predictive, and we see whether or not we try to predict the outcome and the dummies and see if it validates that, that model. And then finally, after we do all of that, we still backstop this with human volunteer tests. And so, you know, the dummies are foam and plastic and metal. They don’t move like humans do. They don’t say “Ouch,” you know, all of those sorts of things. And we’ve adapted them and we put our best foot forward to develop injury metrics. But there’s no good data. The best data is actually put in humans in the actual seat, in the suit, in the, you know, restraints and running sort of nominal loading conditions and see how we do. And so that’s kind of the high-level soup to nuts, how we get from. you know, what we can do to try to validate these things. We are moving to human finite element models. I think that’s probably the way, you know, in the future, that we will validate these things. So we can take a model of Patrick, size it exactly to him. We could take an MRI scan of him, put his organs in there, get all the tissue properties of his muscles, bones and all of that, and then run those models in simulations and then look at, you know, what sort of injury metrics we might be approaching with those models.

NASA’s Moonikin Campos sits in an Orion chair on the sled for testing at Wright-Patterson Air Force Base in Ohio.
NASA’s Moonikin Campos, a manikin that flew on the Artemis I flight, sits in an Orion chair on the sled for testing at Wright-Patterson Air Force Base in Ohio. Moonikin is continuing its journey of exploration on Earth through a unique series of testing as a crash test dummy. The tests are informing engineers’ understanding of what the experience of flying inside the agency’s Orion spacecraft will be like on crewed missions to the Moon beginning with Artemis II. Credit: NASA

Patrick Estep: Yeah, I personally wouldn’t use me as a model, but I’m flattered.


Host: But you could be a future astronaut.

Patrick Estep: I could be, we’ll never know.

Host: For anthropometric…how do I say it?

Nate Newby:  Anthropometric, yep, you got it.

Host: For anthropometric devices. We flew some of these on Artemis I. Was your team involved in that?

Nate Newby: Yes, we were involved. They were not instrumented because it was the cost and complexity of adding all of the instrumentation at that point. And we had done all this work already to, to validate that the flight was, you know, ready and meeting injury metrics. But we did, and then we had, you know, the dummy on Demo 1 and then we had the Rosie dummy on the Boeing OFT vehicle as well. And so for some of those programs, they were instrumented and we could look back and see that indeed, you know, that the metrics were being met. In often cases with the test flights, it’s a nominal of nominal, and in those cases, generally you’re not learning much injury-wise. It’s really more these harder kind of landings off nominal cases, fault cases, those sorts of things. And so, we did have it, we had the cabin video of it. We saw that the dummy looked fine when it came back.

Host: Yeah, I heard no complaints.

Nate Newby: No complaints, yeah. Frequent flyer.


Host: Well, my next question I feel like really involves all three organizations, which we know astronauts experience changes as they spend a long time in space. So they have different changes including fluid shifts, spinal elongation, some people grow, what? A couple millimeters or a couple of inches while they’re in space?

Nate Newby: Inches, yeah.

Host: Inches. Impressive. They have vision differences, things like that. So when they come home, how do you make sure that the person who’s now returning home, which may be different than the person who left essentially because of these changes, how do you make sure they have a safe ride?

Nate Newby: Yeah, I can start with that. So we have different limits for conditioned crew versus deconditioned crew, and we kind of draw that line at about 30 days based on our experience with shuttle and what we know from space station and sort of the condition limits would apply for things like abort. You know, you haven’t been in space yet, and it’s an abort, so you allow even greater latitude where you’re just trying to save the crew. And then we have the decondition limits, which are a knockback factor that we apply to all of our limits based on all the research that’s been done on space station for all the years. For my area, I’m really interested in bone integrity, bone strength, muscle integrity, muscle strength, and sensory motor in the sense, can the crew brace? Can they brace in a timely manner so they can time the coordination of their muscles and in a forceful manner that they can, you know, help keep themselves in the seat? We have spinal lengthening going on, which I’m also interested in. I’m not sure how that exactly correlates with some of the lumbar spine injuries we’ve been seeing in crew on landing. But we’ve got to make sure that the seat fits, not only on the launch side, but also on the return side when it’s real important that they’re likely going to take an impact land load at the end of the mission. We’re also interested in the vision changes. So the sort of SANS or VIIP that we call it now, we know that from research from those experts, that head work accelerations are no bueno after they’ve experienced some of these symptoms from being on space station. So we work with all the vehicle providers to make sure that the crew are either flat or slightly head up through the whole entry, descent and landing. And we don’t have head down periods which potentially could exacerbate those kind of issues.

Patrick Estep: I think as the shortest one in the group. I’m also very interested in spinal elongation.

Nate Newby: Right.

Host: That was Patrick, by the way.

Patrick Estep: My one bad joke. I’m afforded one. Come on.


Nate Newby: Right. We’ll give it to you. We’ll allow it.

Brian Prejean: Yeah, after essentially they land and get back healthy and safe. I know the landing site is very well supported and there’s a huge medical team and they even started getting assessed for some of those changes at landing at R+0. So some that you mentioned like sensory motor, I think ours being the global NASA community and the crew members themselves, the ultimate objective is to return the crew back to their pre-flight level. So obviously we want to make sure they are prepared as much as possible before flight, whatever that means. Some of that being, you know, just conditioning, physical training, work hardening, as Nate mentioned. And then when we get them back, the Med B test that I mentioned, we’ll do those at R+5 and 30. So there’s kind of that one-month window where they really are heavily evaluated and monitored, but then they’re working every day with their ASCRs and MSK team from a physical reconditioning rehabilitation perspective. And they are focusing a lot on not just the muscle and aerobic, but the sensory motor, getting that back. And a lot of that is tied to their vision as well. Just being able to track when they’re running and being able to run without, you know, their whole visual field just sway back and forth. So we think they do, the crew members that is all do really well at returning back to their levels if they put in the time and effort and work with their team within the first couple of months. So from our perspective, and you know, with everything they do on ISS and the vehicles, they’re coming back in so far, I think they’ve got good support platform there.

Host: Nate, I have one more quick question for you. Your team also works with experts and scientists from the Air Force, the Army, Federal Aviation Administration, National Highway Traffic Safety Administration, NASCAR, lots of universities. What kind of info sharing do you give to this really broad range of different groups and what do you learn from them?

Nate Newby: Yeah, I think a lot of it’s going the other way. I learn a lot from the analog environments. I mentioned that we do all of our impact testing up at the Wright-Pat Air Force Base. That’s in invaluable to us and that facility. We also used this model called the Brinkley Model from the Air Force. So there was a lot of work, especially in the ‘60s done on ejection seats with aircraft and how to keep crew, you know, air crews safe during, during eject. And so we’ve learned a lot. And actually that model is still a requirement today that we use here at NASA.

NHTSA, we were at one point, National Highway Traffic Safety Administration, we are at one point debating using the latest crash dummy, which is called the THOR. It’s got better senses, better bio fidelity, all of these things. So NHTSA loan to us one of those dummies so that we could use it in a test battery to see how it compared with humans and how it compared with the hybrid three, which is kind of the automotive standard. We do a lot of work with universities, of course. We do things like look to the future like lunar landings, what does it look like if you’re standing, you know, and not seated during kind of like Apollo. Apollo crews were all standing and what’s the best way to restrain people like that? What do the loading look like under those conditions? And so Wake Forest and others have, we’ve relied on them to do those sort of look ahead analyses.

Then, yeah, for the auto racing industry, we’ve done work with NASCAR or IndyCar. We’ve learned a lot from, from them. We’ve shared some of our data with them. They’ve shared all their crash data with us. You know, the IndyCar drivers, they have an accelerometer in their ear and they have the acceleration of the vehicle. So we can look at how best, you know, they mitigate injuries. One of the things they use is called the HANS Device. It’s a way to kind of keep the helmet with the head and not applying excess forces on the head when you get into a crash. We’re using a very similar sort of system in the Orion OCSS Suit that we’ve modeled on that system. And so, yeah, we rely heavily on our collaborations and have learned a great deal from, you know, people in this field, occupant safety that’ve done research for 50 years or better.

Host: I think most people wouldn’t know that we do that kind of knowledge transfer. So that’s very cool. But I also think most people wouldn’t know, cause I didn’t know, that the Apollo astronauts were standing when they landed on the Moon. Is that being investigated for future lunar landings too?

Nate Newby: It is. You know, they were really worried about mass and so in order to save mass, they didn’t use seats in the Apollo landings. And so, yeah. And so all of those landings were all standing. One of our providers is looking at standing landings again. So there’s a lot of going back backwards and looking in the national archives for any relevant data we can glean from Apollo and then trying to apply that to these future missions. Unfortunately, we tried really hard to get the actual acceleration landing data from Apollo and that wasn’t available, but from other data that we could gather, we could recreate the landing extract, what the likely accelerations were. And in part we use that to set new limits for standing landings for any provider who wants to pursue that for mass savings or any other reason.

Brian Prejean:  An interesting crossover topic as well, because there’s another lab in our area that’s doing investigations into landing accelerations, but as they relate to orthostatic intolerance. So if you stand up too quickly and the blood rushes from your head, that’s going to be a bad thing and you have risk of passing out. And so that would be landing on the Moon or landing a lander on the Moon would be the bad time to do that, to lose consciousness, because of those accelerations combined with all the changes that, that you were describing, fluid loss, fluid shift, maybe some deconditioning that’s a risk, a human system risk that’s being looked into. And so these questions of, yeah, how quickly should they descend and what posture should they be in when they do that or are being looked into, not by our group. That’s still very relevant to our area, I think.

Host: Wow. I had no idea. Thank you so much. I have one question really for everyone. It’s our last question. How do your teams work together to share data and make sure that everyone’s communicating and you’re getting the latest of what you need?

In the foreground, the Moon is pictured. To the left is the Orion spacecraft, which astronauts will take to orbit, and eventually land on the Moon, as part of NASA’s Artemis program. Credit: NASA

Patrick Estep: Oh, they’re both looking at me, so I guess I’ll go. I think kind of like we’ve highlighted here, there is a lot of overlap. We’re putting humans in space. We’re asking them to do all of these different things to be launched on vehicles, to survive on the vehicles during transit, to go down to the exploration service and to do EVAs. And so for us, there has to be all of that because there’s humans there in the loop. I think a lot of times, no singular one of our teams or even any singular lab kind of within the human health and performance realm is looking at each and every individual facet of human health and performance. That would be impossible to have that much subject matter knowledge in any one team’s brain. And so we kind of have to bring it all together. Really I think when we design studies or testing, we put a lot of things in place to try to go talk to and integrate with all these different groups and subject matter experts from the front so that we can design tests to get the best, most applicable, relevant data out to try to answer all of the questions as concisely, but also efficiently as possible. So there is a lot, but I think a lot of times it’s really all the way up at the front when we’re talking about designing a test or a training simulation or whatever it may be that we can really sync up, not just with ourselves, but with so many of the other groups in human health and performance. It all kind of ties together.

Nate Newby:  Yeah. We kind of tugged on this before with the work hardening. So this is something definitely we partner with the exercise folks, you know, that we, you know, are assessing the forces and torques required to do certain things in the suit, and we can feed that information over to the exercise group. The other thing we’re looking at is, you know, when with a lot of these landings, we see some injuries in the cervical spine and the neck. And it’s often, and you can Google this and find in video say of Soyuz landings, you know, it’s a real rapid motion of the head and neck right at the impact. And so working with these guys to develop ways to train the neck, you know, and come up with exercise programs, that’s kind of challenging, but could help our crews out there. And then on the suit side, you know, I kind of touched on this before, but performance, suit performance, and injury are kind of on a spectrum. You know, if performance starts to degrade too much for whatever reason, it can definitely leave you susceptible to injury. And if you’re injured, then your performance is not going to go very well likely. And so, yeah, it’s important that we continue to exchange information like we do. As Patrick mentioned, not only in our group, but then outside of this group, people from bone health and muscle, you know, cardiovascular health and all these other programs.

Brian Prejean: Yeah, no, much more to add for me. Those are great words. I think as was alluded to already, you know, the integrated, collaborative, multidisciplinary approach is just necessary in this kind of environment. And that definitely goes beyond our lab or even the agency, especially now with all the commercial providers coming on. But the specific focuses and priorities that we have in human performance, it does facilitate that type of collaboration, having this integrated lab approach. So as Patrick was mentioning, the project and product development really takes a proactive approach to say, “Okay, we know that this is going to take more than just somebody who knows exercise to solve this, so who else do we need to pull in?” And we have a really impressive array of those diverse skill sets within our lab. So it makes it a lot easier.

Nate Newby: It’s funny, when we interview potential job candidates, we all glom onto them, right? We all say, oh, we try to poach each, each other’s people. So yeah. Cause we end up looking for a similar sort of skill set that’s diverse and can spread across all of our groups. So Patrick steals my people all the time.

Patrick Estep: It’s because you turned me down for the job, Nate.

Nate Newby: Revenge, revenge.

Patrick Estep: It’s all coming full circle now, isn’t it?


Brian Prejean:  It’s in the works because they’re hiring them into SSEO, but you know, we’re just in integrated lab, so I get to use their time and play tug of war with Patrick.

Patrick Estep: Yeah. When our people get bored and tired and they want to go do something boring like exercise, they can come to you.

Nate Newby: Oh wow.

Brian Prejean: It’s mostly the flow in the other… I don’t even have a counterargument. He’s got spacesuits and I can’t argue against that.


Host: It’s getting spicy in here.

Brian Prejean:  Whoa. That’s where I want to escape and have fun. Yeah. I go join Patrick’s.

Patrick Estep: It is really great. I do think that’s another thing our lab does really well because we do work in such a unique niche, yet broad subject matter. It is important that we bring people together with backgrounds in exercise, physiology, kinesiology, injury, biomechanics, human health and performance. And we all have to work together in different ways and across different disciplines as well. Whether that is on the, you know, physiology side or as an engineer or as more of a kind of logistic and operations type of person. There’s so much that goes into making all the great things that we’ve talked about today happen. And so it is great to work with not only these guys, but the rest of the team that supports all these things.

Host: And it’s been really great to talk with you all. So thank you so much for joining the podcast today. I had a really great time learning all about H-3PO.

Brian Prejean: Yeah. Thank you. It was honor.

Nate Newby: Thank you.

Patrick Estep:  Thank you so much for having us.


Host: Thanks for sticking around. I hope you learned something new today. Check for the latest updates and You can find us on Johnson Space Center’s social media accounts on Facebook, X, and Instagram. Use #AskNASA on your favorite platform to submit your idea and make sure to mention it’s for Houston We Have a Podcast. This episode was recorded on February 23, 2024. Thanks to Will Flato, Dane Turner, Abby Graf, Jaden Jennings, Dominique Crespo, and Gary Jordan. And of course, thanks again to Patrick, Nate, and Brian for taking the time to come on the show. Give us a rating and feedback on whatever platform you’re listening to us on and tell us what you think of our podcast. We’ll be back next week.

This is an Official NASA Podcast.