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Season 1Oct 27, 2017

Les Padilla, Hardware Manager of the Extravehicular Mobility Unit (EMU), talks about spacesuits: how they work, what they're made of, how they've evolved over time, and what they'll look like in the future. HWHAP Episode 16.

Exp 51 flight engineer Jack Fischer spacewalk

houston podcast ep16 spacesuits

“Houston, We Have a Podcast” is the official podcast of the NASA Johnson Space Center, the home of human spaceflight, stationed in Houston, Texas. We bring space right to you! On this podcast, you’ll learn from some of the brightest minds of America’s space agency as they discuss topics in engineering, science, technology and more. You’ll hear firsthand from astronauts what it’s like to launch atop a rocket, live in space and re-enter the Earth’s atmosphere. And you’ll listen in to the more human side of space as our guests tell stories of behind-the-scenes moments never heard before.

Episode 16 features Les Padilla, Hardware Manager of the Extravehicular Mobility Unit (EMU), who talks about spacesuits: how they work, what they’re made of, how they’ve evolved over time, and what they’ll look like in the future. This episode was recorded on April 13, 2017.

Houston, we have a podcast


Gary Jordan (Host): Houston, We Have a Podcast. Welcome to the official podcast of the NASA Johnson Space Center, Episode 16: Spacesuits. I’m Gary Jordan and I’ll be your host today. So if you’re new to the show, this is where we bring in NASA experts– scientists, engineers, astronauts– all to tell you the coolest parts about what’s going on here at NASA. So Allyoop on Twitter is asking if we can do an episode on spacesuits. Well, thanks for your suggestion, Allyoop. Let’s do it! Today we’re talking spacesuits with Les Padilla. He’s the EMU hardware manager at the NASA Johnson Space Center in Houston, Texas, and that just means he manages the hardware on those classic white spacesuits you see when you think about astronauts. We had a great discussion about how those spacesuits work, what they’re made of, how they’ve evolved over time, and what they’ll look like in the future. So with no further delay, let’s go light speed and jump right ahead to our talk with Mr. Les Padilla. Enjoy.

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>> Houston, we have a podcast.

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Les Padilla: I like to explain to others, I feel like a kid in a candy store when they ask about it.

Host: Yeah.

Les Padilla: It’s awesome to both see the past where it came from and the future designs where we’re maybe headed towards.

Host:That’s right, and that’s what we’re going to talk about today, all of those things.

Les Padilla: All right.

Host:So I hope you– I see you have a large binder of notes. It’s actually one page. But yeah, so we’re going to talk about it all today. So first of all, spacesuits. Let’s start from like the overarching, like what is a spacesuit, why do you need a spacesuit? I think the closest thing that I’ve been described is like think of it like a spaceship that’s shaped like a human body. Is that kind of right?

Les Padilla: That’s a fantastic description right there.


Les Padilla: A lot better and a lot shorter than I could’ve said it.

Host:Okay so what are they, how, like why a spacesuit? Why do we need that? Why can’t we just use the fancy spacecraft with like arms on it or something like that?

Les Padilla: Yeah, so at some point, people before us decided, “we want to go to space.” And after that they decided going to space wasn’t enough. We want to go extravehicular, outside the spaceship– whatever spaceship it is, from shuttle to station, to before those and the mercury missions all the way in the early days. And the spacesuit, the purpose of it is to be sort of as you said, a miniature aircraft, but allow us mobility, flexibility, maneuverability, so that a crew member could move around when they’re doing work or just experiencing the environment out there. Like in the early days in Gemini when they went out the door.

Host:That’s right, Ed White.

Les Padilla: Yeah, absolutely, you got it. Just experiencing the environment, did not want to come back in.


Les Padilla: Or later days, even where we are right now with the International Space Station, where there are maintenance activities and there is– we’ve already completed the assembly, so it’s maintenance activities is where we’re at. We need to be able to go out there and do more than just fly around and enjoy the scenery. We need to be able to turn bolts. We need to be able to pull out large batteries and put them back in. And so they need something that offers dexterity and yet protection from the very harsh space environment.

Host:You know, we just saw that, because we just did the spacewalk the other day, right. That was the second of three planned ones, and that was when they were putting on some of the shields and everything.

Les Padilla: Absolutely.

Host:And they did some robotic work, right, with the station’s robotic arm. They took the pressurized mating adaptor, moved it to a new place, but they needed human hands to actually connect the cables and actually put on the shields. So it makes sense, right– you need the suits because there’s some things that robots just can’t do, I guess, right?

Les Padilla: Yeah, not yet, not where we are today. You can’t go to space without EVA.

Host:Yeah, that’s true. Okay, so like going back to Ed White and Gemini, that was– the first one was– oh, no, I had– I just had it. I want to say June 1965? ’65, there it is. All right, yeah. He came out and they actually used the air gun to move around. And super famous video of watching him just like drift out, and he’s got the umbilical, and he’s got the air. So I’ve got to ask– what was the point of that air gun thingy? And then why do we not see anyone use those anymore?

Les Padilla: Yeah, great question, yeah. And so there’s probably people wiser and more experienced that have extra details on that, but at a high, general level it’s just directional control. So you’re out there in space. We call it– we say no gravity. There is some gravity, but it’s microgravity, very low, and for all intents and purposes you’re freefalling towards the earth. And so unless you’re holding onto a handrail or the vehicle itself, you will continue to float, and the gravitational pull to the surface of earth will begin to bring you down. So as soon as you go out that door, you’ve got to have a way– it could be a tether or a rope to pull you back in, but a way to maneuver around the area you want to go. And so the air gun provides a small propulsion capability to navigate.

Host:Okay, makes a lot of sense. So, okay, they’re going out and using the air gun, but now I guess they have– it took them a while, right, during the Gemini? That was kind of a lot of the point of the Gemini program, was to figure out how to do stuff like this, how to do space rendezvous, and how to do spacewalks. It took them a while, right? So that was Gemini 4 was when Ed White came out. And then it wasn’t until Gemini 12, Buzz Aldrin had put in some procedures for neutral buoyancy laboratory training, where they actually train in the water to see how they can move around, because everyone was getting sort of tired when they were going out because they didn’t have the procedures yet. And they finally nailed it for Gemini 12, right?

Les Padilla: Yes. Spacewalks are tough, tough jobs.


Les Padilla: The astronauts are just amazing the way they do work so seamlessly. And as trained professionals, they make it seem easy, but inside those suits– because I’ve seen the suits come out– there’s a lot of sweat in there. There’s a lot of hard work that goes on for those astronauts, and it is not easy. And as you said, training on the ground is pivotal to be able to make those activities look seamless on orbit.

Host:Yeah, I’m totally not following the script right now, but I mean, so the NBL training that they do, they do it in the neutral buoyancy laboratory– super big pool. They have like 1-to-1 scale mockups of the outside of the International Space Station, so when they actually go up there and they– well, in the neutral buoyancy laboratory, they train in a spacesuit, pretty much. So they know exactly how it feels, and where things are, and they know how to move from place to place and use proper tools. Because once you’re out there, you’ve got to know kind of what you’re doing and what to expect, because you might encounter some hurdles. And there have been some hurdles in the past.

Les Padilla: There have been, absolutely. All in that neutral buoyancy lab, you’re right. They actually train in a spacesuit that is almost exactly like the ones they fly in. Small little differences, like the white backpack, which is the engine of the spacesuit, the primary life support system. In the neutral buoyancy lab, it is just a hollow shell and we have umbilicals, long hoses, that supply the air and the power to the suit.


Les Padilla: And the tools will have things that are changed on them to make them more neutral buoyant, so they’ll float in water and don’t sink directly down to the bottom of the pool. But overall, it is, as you pointed out, just like the flight hardware, and the suits are very similar to what they use on orbit so they can train and be prepared. Because as you noted, there is no go out the door and, “I’m not quite sure what I’m doing out here. Let’s go ahead and plan another day.”

Host:“Let’s figure it out. Oh, we can’t do it. I guess we’ll come out again.” Because yeah, it takes a long time, right? Because I mean, I was listening to Shane the other day, because he just landed a couple days ago at the time of this recording, and he was saying it takes hours of prep work beforehand, right, like four hours. They’ve got to pre-breathe, they’ve got to do all these things, put on the suit, and then they go out and it’s another seven-ish hours that they’re out there. Then they come back and they have like a two-hour debrief. I mean, that’s a long day. He called it one of the most challenging– especially physically and mentally– challenging things about flying in space.

Les Padilla: Yeah.

Host:I can imagine. And especially– I mean, that’s what they train for, right?

Les Padilla: That’s right.

Host:In the Neutral Buoyancy Laboratory they do like six-hour runs or something like that. Kind of the same, they do some prep work beforehand. But they get used to it, and they do a lot of that training.

Les Padilla: So I’ve never been, obviously, out the door in space. I’ve never been an astronaut in that aspect, but Gary, one of the best ways that I can describe what you just said is have you ever gone skydiving?

Host:I have, one time!

Les Padilla: Yes, then you know! So the stimuli when you make that decision of “all right, I’m about to get out of a perfectly good airplane,” and you go out, just everything going on. It is– the first time you go, it’s very hard to concentrate.

Host:Oh, yeah.

Les Padilla: It’s kind of good with that tandem thing, the guy going, “look at your altimeter.” [ laughter [ but imagine freefalling like that for seven hours straight while having to do maintenance work on the space station and watch your display control module on your emu and listen to people on the ground and inside the station. And that’s just a shadow of the difficulty of the job that those guys do.

Host:Okay, well, when I went out the door for whenever I went sky diving, my legs went weak and I always had the guy strapped to my back, and he had to like push forward to the end of the door and actually like push me out. He did the whole like instead of “we’re going to go out on three. One, two,” and then we went out. So I was like– I was totally weak, but I can’t even imagine. Because my heart dropped on that first run, and then it was thrilling for a while. But I mean, everything happened so fast. And now like you said, take that and then stretch it over a super long period. I can only imagine. Okay, so let’s take a step back and let’s go back to kind of where I was originally supposed to go, but talking about spacesuits, and first of all, why do we need it?

Les Padilla: Sure.

Host:You know, you need the dexterity, obviously, but there’s a human aspect to that, right? You can’t just, “oh, you know what, something’s broken on the outside. Let’s just go out the hatch and torque it–” torque it, what am I saying? “torque it with a wrench or something and fix it.” You need, like you said, you hinted at life support a while back with the backpack. So what’s it about– this may seem a bit obvious of a question, but what’s it about space that the human body cannot just go out and do tasks in?

Les Padilla: Sure, and you know, I think most people could tell you that space, yeah, it’s a dangerous environment. But why is it is we’re getting at– well, the spacesuit provides the capability to regulate temperature. In the low earth orbit, as we call it, where the International Space Station is, temperature ranges during the EVA days can swing from negative 148 degrees– so that’s 148 degrees Fahrenheit below zero up to 248 degrees. And those are estimates that can be higher or lower, but that’s a huge window that the human anatomy was not designed to work within without protection.

Host:Yeah, I feel like Houston, Texas can get up to about positive 248 degrees, but– I know it’s not even close, but–

Les Padilla: Not negative 148, though.

Host:No, not even– no, not even 148 to me. But you’re right, that’s intense. So how does the spacesuit protect from that, the extreme negative and positive temperatures?

Les Padilla: Yeah, so there’s a lot of planning up front in choosing days that we go EVAs, we call it– extravehicular activities.

Host:Thank you.

Les Padilla: Spacewalks.

Host:We try to stay away from those acronyms, but yes, spacewalks, right.

Les Padilla: We choose special days that have the least impact– more habitable conditions would be a better way to put it. But at the end of the day, even on the best days, temperature swings when the sun’s looking at you to when the sun’s behind the station are large swings that can be 100 degrees. And so that’s where the spacesuit comes into play. And the spacesuit was designed to work in these environments. There are– the outer layer is white because it reflects heat.


Les Padilla: Little simple things like that.

Host:Okay, now you know why the spacesuits are white.

Les Padilla: There you go. All right, whereas if it were black it would absorb the heat, get a lot hotter quicker, and make it hard for the performance of the suit and the individual inside. The multiple insulation layers on the suit itself– there are seven layers of insulation within the outer layer of the spacesuit.


Les Padilla: And without getting into details, those are specifically to reflect heat and to protect the crew members, and keep in the proper environment heat that’s necessary inside the suit.


Les Padilla: So it may be hot out there, but when that sun goes behind station, it gets very cold. That crew member wants a certain amount of heat kept within that spacesuit.

Host:I would think so, yeah.

Les Padilla: Absolutely, absolutely.

Host:Negative 148 is pretty cold.

Les Padilla: But lower levels of that spacesuit is the bladder itself, and that gets into one of the next important aspects of the suit, which is providing an oxygen environment.


Les Padilla: You’ve got to be able to breathe in space, and there is a 100% oxygen environment inside the suit. And as Gary knows, and we’ve talked about it briefly before, 100% oxygen environment is not natural.


Les Padilla: It’s not what we experience down here in ambient or one atmosphere pressure, where we get– what is it, 78% nitrogen?

Host:Nitrogen, yeah, and a little bit of carbon dioxide, just little bit.

Les Padilla: Just a tiny bit, tiny bit. But when the lower pressures of the suit, the suit pressure is 4.3 psi when we go on spacewalks.

Host:And that’s about the pressure we feel here on earth?

Les Padilla: The pressure we feel here on earth is 14.7.

Host:Whoa, okay, so a little bit lower.

Les Padilla: So almost a third, a third.


Les Padilla: Close to a third, a fourth of that.

Host:Okay, so what would that feel like? What’s the next comparable thing of what 4 psi would feel like to like us here on earth?

Les Padilla: Ooh, that’s a tough one.

Host:Yeah, hard to compare, right?

Les Padilla: That’s a tough one, because I’ve been inside of a suit so I know what it feels like, but I haven’t been inside something else that has that 4 psi of pressure that I could do a 1-to-1 comparison of. I would say putting multiple gloves on.

Host:Oh, okay. Yeah, so it’s really strenuous on your hands, then?

Les Padilla: Absolutely. When you’re out– compared to a near zero pressure environment like the space is, 4.3 is– it’s fatiguing. You’ve got pressure on your hands, your body. To move, you’ve got 4.3 pounds of pressure over all of your body that you’re working against.

Host:Pretty stiff.

Les Padilla: That is. Compare that to the Russian Orlan. Their suit is 5.8 psi. That’s even more difficult.


Les Padilla: You compare that to some other spacesuits that we’ve looked at in the past that are even higher pressure, and you can see why it gets– we need low psi. And so 4.3 is not perfect with zero resistance, but it’s a nice sweet spot that our crew members are able to work, and those that have ran in both the Russian suit and the American spacesuit have said, “yeah, it’s a lot easier, this 4.3 psi.”


Les Padilla: Yeah. But that drives us to why the oxygen’s at 100%. At that lower pressure, we need the 100% oxygen.

Host:Oh, okay. So that’s how you counter, you know, we’re in the 14-something psi here, so then–

Les Padilla: Lower oxygen concentration.

Host:Lower oxygen, okay. That makes– and that brings us back to the pre-breathing that we kind of alluded to earlier.

Les Padilla: Yes, sir.

Host:You need to kind of purge your body of nitrogen, is that right?

Les Padilla: That’s right.


Les Padilla: That’s right, otherwise the oxygen toxicity is the concern if you don’t go to that prebreathe protocol.

Host:Okay, all right. Well, awesome. That explains why you need the pressure that you do. Okay. But I guess if you were to drop it any lower it would be a little bit hazardous to your health, right? Like 4.3 is probably the sweet spot?

Les Padilla: 4.3 is the sweet spot with what our current spacesuit is certified to.


Les Padilla: You can adjust it different ways. I mean, it’s kind of like if you change the pressure, now you’ve got to play with the oxygen. You’ve got to play with what is the suit capabilities at that level. 4.3 is the perfect sweet spot for what this suit is certified for.

Host:Ah, I see. Which is doing work on the outside of the International Space Station.

Les Padilla: Absolutely.

Host:Cool, very cool. So you’re outside– you alluded to the fact that we’re in low earth orbit, right, means we’re in the microgravity environment.

Les Padilla: Yes.

Host:Tiny bit of gravity, not too much. Is it fair to say a little bit of atmosphere, too? Like tiny, tiny bit?

Les Padilla: Tiny bit.

Host:Yeah, that’s why we need to boost the station every once in a while.

Les Padilla: Yes.

Host:There’s like a tiny little bit of drag. But how much are we protected from the Earth’s, I guess, magnetic sphere? How much do we have to worry about radiation at that altitude?

Les Padilla: Yeah, no, absolutely. Great question. And it’s a great concern. There’s a reason that crew members are limited for how long they can stay up on the International Space Station. That’s one of the players in there is the health themself. Radiation, I mean, I guess the most high level way to describe it is subatomic particles that are supercharged we get from the sun, we get from outside our milky way galaxy, and that can come in, and they just tear right through your DNA. And that can be acute if there’s large doses of radiation, which fortunately aren’t a concern where we work in low earth orbit.


Les Padilla: But over a long-term exposure, there could be chronic effects. Like when you rearrange the DNA, it can lead to cancer, other diseases. So it’s very serious. We have a team dedicated to radiation and making sure we protect our crew members. The spacesuit is designed to provide some level of protection when they’re out there for that limited spacewalk on the International Space Station. The space station itself is also designed to protect the crew members from certain levels of radiation that we get from solar wind from the sun.

Host:Okay, all right, yeah. So I guess the suit is designed for what– for that purpose.

Les Padilla: For that purpose in limited spacewalks, yeah.

Host:Okay. Well, so how is that different from other I guess extravehicular suits? You know, the suit itself has evolved over time, right? But I heard, I think the technology is sort of adapted from 1970s technology, and then they just made it a little bit better, right?

Les Padilla: Sure, sure.


Les Padilla: Yeah, so you have– I mean, we can go right through them. You have all the way back from the mercury suits, the first ones we went up there with inside of the mercury, and those were completely designed for, hey, the crew member is staying inside this vehicle. But in case we have cabin depressurization, we need the guys to have a suit so that they can exist for hopefully the period of time to get the cabin back pressurized. Those were early suits. We had even before that pressurized suits for our pilots and balloonists that were going high altitude.

Host:Right, yeah, and we still do, right? We have the pilots over at Ellington field here in Texas that wear those pressurized suits for the wb-57s, those high altitude planes.

Les Padilla: Yep, yep.

Host:So they’re, I guess– are they technically in space at that altitude? I think they are, right? Is it 16 miles that is like you’re technically in space?

Les Padilla: You’re getting beyond my knowledge here.

Host:I don’t want to get lost.

Les Padilla: So maybe

Host:You hear things, but yeah. But I know they do wear the suits, and they have to. They have to do the whole same thing that astronauts do. They have to prebreathe and all of that kind of stuff. But yeah, so–

Les Padilla: That’s where spacesuits started from.


Les Padilla: That was the first stepping stone, was high altitude flying.

Host:Yeah. So I guess those mercury suits that you were talking about, is that where kind of the launch and entry suits kind of went towards? Whenever you’re launching into spacecraft, you have to wear a specific suit in case of that, right, sudden depressurization? Is that like the reason?

Les Padilla: So absolutely, the mercury suit was a– you know, we stand on the shoulders of those who designed that mercury suit. And he next suit was Gemini after that, and the next one after that, and all the day to Apollo– yes, absolutely do those provide data and insight towards the aces suit, or the launch and entry suit that we’re now working on for next vehicles.

Host:Oh, right.

Les Padilla: So yes, data from those suits was pivotal to make our current launch and entry suits. I mean, one of the most– the Gemini suit that came after the mercury, that was the one that Ed White went out on his EVA in. That was the most polarizing or one of the most well-known ones that you’ll see in a lot of the old movies with the aluminized nylon outer covering, where it’s all shiny, and a lot of zippers here and there.


Les Padilla: Yeah. Every movie that ever had science fiction laid to it– my parents watched– I remember seeing the shiny suits.


Les Padilla: And so that’s Gemini.


Les Padilla: To set the tone on that. And the reason for the shiny suits was they were in that time– we had a lot of data, but the big concerns were thermal and radiation, as we were talking about earlier. And so you’ll see that aluminized material on the Gemini suit early on, because they really want to make sure they are guys who protected, so they went all out. As we got more data and we figured out what we needed and where we need to grow in, and where we didn’t need so much, you saw that shiny aluminum or nylon, it went away.

Host:Right, yeah. And now we see the white suit.

Les Padilla: You got it.

Host:All right, yeah. And then we saw the famous white ones like on the moon, walking on the surface of the moon.

Les Padilla: The Apollo suits.

Host:The Apollo suits. And then we– now we have the white suits on the International Space Station that we use all the time. So kind of going through a little bit of the features of those suits, I want to– I always wanted to know, whenever you look at a spacesuit, the first thing, I think, your eyes go to is that shield, that gold shield. What is that?

Les Padilla: Yeah, so the– I think the term is goldized.


Les Padilla: Yes.

Host:I like that.

Les Padilla: That gold visor is like basically very fancy sunglasses.


Les Padilla: So the visor itself if a Lexan material that you’ll find in some of your household goods. It is specifically to protect the crew members’ eyes from sun.


Les Padilla: And so there’s a gold sheet that goes over that. It has great characteristics of blocking harmful UV rays and other rays that would come from the sun, and help the astronaut continue to be able to work in that spacewalk environment.

Host:But they can kind of pull it up, right, during night times. It’s like sunglasses are. If you walk from outside to inside and it’s suddenly dark, you take your sunglasses off. So it’s kind of–

Les Padilla: Sure, they’ve got a cool knob on the side of the helmet. You just flip that visor up, and what you really neat is there are opaque visors on the side that we rarely see in pictures.


Les Padilla: Most pictures you want to see the face or at least the cool gold visor. But there are completely opaque white visors that can cover– maybe if the sun’s on your right side, it can block on the right, or the left, or halfway down the front. And then the gold visor, as you pointed out, can completely cover your face at full sun, or partially, or just completely remove it all together. Slides back behind the helmet bubble underneath.

Host:Oh, okay. Oh, so I’m thinking about the picture of– I want to say it’s on Apollo 17, right, where you have the– I think it was Gene Cernan, I think, posing, and then he has two of those opaque visors down–

Les Padilla: Ah, now I’m with you, yeah.

Host:Yeah, and he’s got the earth behind him or something.

Les Padilla: You got it, you got it.

Host:I’m thinking about that picture right now. So if you don’t know that picture, go look that one up, because that’s what he’s talking about with these opaque visors. It’s like those white shields that come down on the sides.

Les Padilla: Absolutely.


Les Padilla: And the Apollo suits are the first suits with that famous fishbowl type helmet. Remember that? If you look at your earlier suits, they have round visors that are fixed, but they’re more oval or smaller in shape, so it’s limited view. In the Apollo suits, and you’ll see it on the current suits on the station, you have the full fishbowl helmets so you can almost have a complete view side to side in front, a little above, limited below by the neck ring, but a much bigger field of view from the Apollo and the current suits we have today.

Host:And that sounds like the perfect reason to do it, right– they learned. They said, “all right, I would like to have a bigger field of view,” so they designed a helmet and then went, “okay, now I can see a lot more.” So what’s the– I know that one of the things that I always wanted to ask is I’m sure– you’re outside doing a spacewalk for hours, right. Your nose has to get itchy.

Les Padilla: Man, you knew your nose would get itchy. [ laughter ]

Host:How do you– like what if you just feel an itch? Like, where do you go?

Les Padilla: Yeah, so–

Host:Don’t they have like Velcro or something? Like hard Velcro they can scrub their nose on or something?

Les Padilla: So there are. There is something called a Valsalva. It’s a strange name, but it’s kind of a– not to get too into the details– it’s a foam block that’s fixed inside the helmet on the neck ring.


Les Padilla: Now, the purpose of this item that’s called a Valsalva is for when you’re going through prebreathe and you’re pressurizing the suit before going out the door. Like when you go up in an airplane, once that cabin starts pressurizing, your ears can pop. That’s uncomfortable. For us flying in a plane, and especially for someone inside of a spacesuit. Only they can’t grab their nose and blow the air out to equal the pressurization. So they have these Valsalva’s they can fit on their nose, and they can kind of– it serves the purpose of blocking the nasal passage so they can make sure that their ears don’t pop.


Les Padilla: So you can swallow, or you can push down your nose on this block to equalize the pressure there. And all that long story to say, if you can reach your nose down there and scratch on that block, that could be an option, otherwise you’re out of luck.

Host:Yeah, yeah. Well, I didn’t even think about that. Like I was thinking about itchy nose, but of course– what if your ears have to pop? Now you have a thing to do that, too.

Les Padilla: Absolutely.

Host:That’s pretty cool.

Les Padilla: Like you said earlier, it’s through these generations of suit evolution they’ve learned along the way, with great crew feedback of “hey, we need this.”

Host:Yeah, yeah, exactly. Well, yeah. You’ve been doing– the first spacewalk was, we said, in 1965. So you have a lot to learn from the mid-60s to now, obviously. So what about like– I mean, again, thinking about you’re outside for that long. When do you eat? Do you eat like right beforehand? Like before or after the prebreathe? Like, I would just get so hungry. I have to eat like every two to three hours.

Les Padilla: I’m with you, Gary. That’s probably the only reason we’re not astronauts– we’ve got to eat every two or three hours.

Host:That would be, honestly– everything else I qualify for, obviously, but I have to eat every two or three hours, or I can’t. [ laughter ]

Les Padilla: So I would say that’s crew member specific, where you see as– I don’t know about you, but when I would run marathons, I had friends that could eat a burger before a marathon with no problem. That’s not this guy.

Host:Not this guy, either. No way.

Les Padilla: And so, same thing with crew members. You have some that– they have a lot of time earlier on where it’s recommended, “do not eat past this time.” And there are some that’ll eat right up along that barrier, and there are some that’ll stop eating way before that. Because naturally, when you eat, not only does it supply energy to your body, but it also causes normal bodily functions as well, which leads into another discussion. [ laughter ]

Host:That’s right. Let’s go into that one. [ laughter ] yeah, so, seven hours. Again, you’re out there for a long time. You’ve got to go to the bathroom.

Les Padilla: That’s right.

Host:What do they do?

Les Padilla: Yeah, that’s a call that you have to answer.

Host:Right, right.

Les Padilla: So unfortunately, as we said earlier, when you’re out in a spacewalk, you can’t just say, “hey john, I’m going to head inside and hit the john.” You’re stuck out there for the duration.

Host:Oh, yeah. And every moment is planned, right?

Les Padilla: That’s right.

Host:So you can’t– you have to just do your thing.

Les Padilla: Yes, absolutely. And so there is no toilet inside the suit. They have– an acronym would be the mag, and it’s basically an absorption garment.

Host:As in maximum?

Les Padilla: You’ve got it, my friend.

Host:All right!

Les Padilla: You’ve got it, you’ve got it.

Host:Bring that absorbency up to maximum.

Les Padilla: So it’s basically a very large depends diaper that they’ll wear on these spacewalks. Now, I can tell you, anyone who’s been inside a suit has zero desire to use that diaper.

Host:Yes, I can imagine.

Les Padilla: Absolutely. But every single one of them is glad it’s there if they get that call.

Host:Yes, yeah. Okay, yeah. I could totally see that. And there’s water, too, in the suit in case you get thirsty?

Les Padilla: Absolutely. Same thing with the marathon– you’ve got to have hydration, and so they have what they call disposable in suit drink bags. Sits right here on the chest, actually Velcros to the liquid cooling ventilation garment, which is how they get the coolant inside the suit.


Les Padilla: Over 300 feet of little tubes run over their entire body that can provide warm or cold water that the crew member can adjust as they prefer on a temperature control valve.

Host:It’s like a space version of air conditioning.

Les Padilla: That’s right, lower thermostat right there.

Host:I’m too cold. I’m just going to turn the heat up. Oh, yeah.

Les Padilla: There you go. Well, sitting on top of that is that bag with water.


Les Padilla: And they’ll take out 32-ish ounces of water as suits them.

Host:Okay, all right. So they have a lot of the things that they need. Obviously you have to plan for that if you’re going to go out in space for that long. That makes a lot of sense. So let’s see. How much do they weigh? That’s a big question, right?

Les Padilla: A big question, and big weight.


Les Padilla: So every suit that’s an EMU– here I am with acronyms again– the spacesuit that our crew members use, our U.S. crew members use is designed to fit from the 5th percentile up to the 95th percentile of men and women. And so with that, you have certain components that are interchangeable and do not change. What I mean by that is like the hard upper torso– picture the torso of the suit.


Les Padilla: You’ve got three sizes, and the majority of crew members might use a large, for example. And they share that large between them. But all the pieces that connect to the suit, the arms, the gloves, the boots, those can adjust in size. And so if it’s a smaller size it’s going to weigh less. If it’s a larger size, it’ll weigh more. But overall, the average weight of a spacesuit itself is about 270 pounds.


Les Padilla: Yeah.

Host:Okay, that’s pretty heavy. Well, on earth, right? So it’s got some weight. So how would– I guess 300 pounds in space would be not so hard to move around, right? I guess you’re in the microgravity environment. But like we were talking about earlier, it’s that pressure. It’s the pressure inside where you have the gloves and you’re trying to squeeze your hands, and that’s kind of the hard part.

Les Padilla: Sure. Yeah, what can be our friend at times is momentum or inertia. And that can be an enemy at times as well, when you’re in that micro environment. So crew members are trained specifically to go slow along a space station. If you get 300 pounds moving, it can be difficult to stop. Now, they can stop it, but it’s just wasted energy. So they go very slowly so they don’t get that large mass moving too quickly.

Host:I’d assume it also helps with conserving energy, too, right?

Les Padilla: That’s right.

Host:So not only do you consider and make sure you can have controlled movement, and you’re going the right pace, and you don’t fly everywhere, using that limited amount of energy because you’re carrying everything with you, right? When we talked about the neutral buoyancy laboratory, you have umbilicals that hook up to all the oxygen and everything you want, but you only have a limited amount with you. Because it’s like backpacking, in space, with a lot more technology.

Les Padilla: Yes, yes.

Host:But yeah, so you really have to conserve. You have to make sure– you have a limited amount of oxygen, so you have to breathe slowly and make sure your heart rate’s not going up, you’re calm when you’re doing it.

Les Padilla: Great point.

Host:Yeah, okay. Because I remember listening when we were on the EVA, doing the EVA– like I was saying, the spacewalk.

Les Padilla: There you go with your acronyms.

Host:We were doing the spacewalk just a couple weeks ago, and yeah, they were saying you’ve got to make sure you take your time when you’re moving around. Because you’re out there for– plan six and a half, it can go up to seven. Last time it was seven hours, four minutes. It can go up to eight, and I think the longest spacewalk ever was almost nine. It was like 8 hours, 52 minutes or something like that.

Les Padilla: It was close.

Host:That’s a long time to be out there, and you’ve got to make sure you’re conserving that energy. So let’s talk about– you briefly mentioned that this is what the emu is meant to do, and we were talking about you get certified to do this, that– what’s happening now to design future suits? Especially not– because the International Space Station is going to be there for the next hopefully decade, I would think.

Les Padilla: Sure.

Host:But after that we’re talking about deep space. We’re talking about planetary exploration. What needs to change about the suit to meet those needs?

Les Padilla: Yeah, so we have a lot of data on what needs to change, but there’s a lot of data that we don’t know yet.

Host:Right, because we haven’t been there.

Les Padilla: That’s right, so like the pioneers with the high altitude flying found, “hey, my suit is only designed to go up at 5,000 feet, and now I’m at 40,000 feet. I think I’m reaching that envelope.” You need new materials. You need new vehicles. We’re going to find out the same thing with the suit. What we do know is that the current spacesuit that serves fantastically at the International Space Station is not a planetary suit. Mobility will be an issue. It is not meant to walk in in a gravity environment. Things we’ll have to look into is– even the Apollo suit, which was lighter, a little more flexible, had some design characteristics to allow the crew members to stoop down and pick up rocks where the current suit couldn’t. Even that suit, there was learning opportunities there where they didn’t expect the amount of dust and dirt that would come in and get inside all the seals. And it sounds minor, but cleanliness can have catastrophic results if you don’t have a certain level of cleanliness.

Host:That’s right. They’re tiny little things.

Les Padilla: That’s right. If they get inside seal and surfaces, you could have a leak, and a leak is something that you do not want when you’re out doing a spacewalk. So there are– the short answer is our current suits are certified for the low earth environment, from radiation requirements, to thermal requirements, to– you don’t really need mobility in your lower half. You just need your upper body to be able to move. Remember, your hands are some of the most important tools you have on space station. Your feet and legs are near useless. They get a little bit of use, but not a whole lot. Well, planetary suits, we’re going to need legs and feet. We’re going to need to use them a lot.


Les Padilla: As you were hitting on earlier, at the lunar activities, we’re only for a couple of days. But if we go to mars, and if we land on mars, we’re going to be out there for a lot more than a couple of days. So we need a suit that’s robust enough to support those requirements.

Host:Okay, so I have– I’m sure you’ve seen the movie “The Martian,” right?

Les Padilla: I have!

Host:Yeah, it’s a good movie. It’s a good movie. So in that one, when we talked about a planetary suit, they had those like skintight orange things. They looked super cool.

Les Padilla: Awesome suits.

Host:Yeah, they looked awesome. But then when they were up orbiting mars, and they had that whole– I don’t want to– in case anyone hasn’t seen it–

Les Padilla: Spoiler alert.

Host:Which, if you haven’t seen it, what’s wrong with you? You need to see it. But they had– when they were orbiting earth, they had the EMU. They had that big white suit. And then it got a little tighter, skintight. Is there a chance that maybe a planetary suit would be skintight, or do you need those extra layers?

Les Padilla: So yeah, great question. It depends on what planet we go to.


Les Padilla: I mean, you hit on earlier that there’s a little bit of atmosphere in the low earth orbit that protects the station to a certain extent and causes drag. Well, on mars there’s atmosphere, as well, whereas other planets or other moons around other planets that maybe in the future we’ll look at going to, will have near zero atmosphere. That’s where you’ll need the multiple layers, like in our EMU right now. When you have that very minimal atmosphere.


Les Padilla: The mars, we should have more of an atmosphere. What you want there– where we may get to more multiple layers is if we need a– if the technology is not available to have robustness in a skintight suit, then you’ll get the multiple layers.

Host:Oh, okay.

Les Padilla: Because obviously you don’t want a suit that’s going to wear out and get a hole sooner. Then you’re in trouble out there.


Les Padilla: But absolutely, those skintight suits like Matt Damon had in “The Martian,” and there’s even been some played around with here in the U.S. that we’ve done some studies for advanced suits. Those are by far preferred in the aspects of mobility. You can move around in those a lot easier without getting pain or abrasion from multiple layers rubbing on you. You mentioned backpacking earlier. Well, if you had a couple pairs of jeans on at one time, and then a number of shirts on, and then a backpack, you’re going get blisters and pain in places. You don’t want to feel that. That’s the tradeoff for if you get a suit with a lot of layers of insulation and whatnot, and then you try to walk distances. That’s going to be uncomfortable.

Host:Yeah. If they do, they’ll probably have to do short EVAs, or spacewalks.

Les Padilla: Or a lunar rover.

Host:Oh, that’s where the rover comes in. So I’ve seen they have one here at the Johnson Space Center called the SEV. It’s like an analog. They see– it looks very much like the one that was in “The Martian.” In fact, “The Martian” kind of copied us. But that’s fine.

Les Padilla: I’m okay with that.

Host:In the back, they had suits on the outside.

Les Padilla: Yes.

Host:There’s a reason for that, right?

Les Padilla: Yes.

Host:And that was that dust thing that you were talking about a little bit.

Les Padilla: Yes, yes, that absolutely plays into it. One of the cool things about the current suit we have today is just the large percentile of individuals that can fit into it. Maybe not perfectly, but they can get inside that suit, small or large, and go out and do an EVA, whereas the other suits that are fixed in sizing– I’m gonna use– obviously the Orlan has been great for many years. Not hitting that at all, just showing the differences.


Les Padilla: You can’t change the cut size. I mean, you either have a 37 inch to 44-inch chest, and you can fit in there, or you can’t.


Les Padilla: And so there’s great things about that. One of the bad things about the emu suit where those– is that you don’t get a lot of shoulder movement, and it’s a lot longer to get in when you have to put the suit together. On the ground with tech support, we can get them in there in 45 minutes. When they’re on orbit, it’s difficult to slide up inside that hard upper torso. All right, now I have to put my gloves on, helmet on. Now I’ve got to put pants on. I explained it in 20 seconds. Those guys are taking over an hour with help, professionally trained people, to get inside that suit.


Les Padilla: So you hit on that suit on the back of the vehicle. It opens up inside that vehicle. You can crawl into that suit from inside your vehicle without having to depressurize the whole vehicle, close that hatch on the suit, and then walk right off the back of the vehicle.


Les Padilla: Pretty neat.

Host:That’s awesome, but you’re right. You have a size thing to consider because you don’t have that adjustable features of the emu that’s on station right now.

Les Padilla: But since the EMU was designed, there is technology that’s allowed us to very quickly adjust the size on some of those fixed suits that formerly we couldn’t. So that’s not an issue today, although it was in the ’80s when we designed the EMU.

Host:Right. Wow. That is so cool. Okay, one more question, and then I’m going to let you go. So we talked about “The Martian” and those skintight suits, but there was one scene in there that he was kind of floating around. And, well, okay, I’m not going to do any spoilers, but basically he had to– he had to–

Les Padilla: I hear spoiler.

Host:Okay, if you haven’t seen “The Martian” yet, turn off the podcast. I’ll give you three seconds. One, two, three. Okay, so he pokes a hole in his glove on the outside, and he has to propel himself out into the thing.

Les Padilla: Yes.

Host:Is that like a thing? Can that happen? I mean, it probably can’t be successful like it was in “The Martian,” but is that a thing? If you were to poke a hole, would you propel yourself?

Les Padilla: So– man. So there’s definitely some Hollywood aspects to that, no doubt about it.

Host:Yes, yes.

Les Padilla: But yes, in theory, you have a pressurized suit. You’ve got two primary oxygen tanks, and then you have a secondary oxygen tank that holds just in itself about 6,000 pounds of pressure of oxygen. So if you have a hole and you’re pushing out air, even if it’s a low force, it will get that body moving. Now, I can’t tell you that it’s going to fly you to a different spacecraft like in the movie, but it would be some level of propulsion, and it would help you out.

Host:That is so cool. All right, cool. I just love that movie. That’s why I keep bringing it up.

Les Padilla: It’s a great movie.

Host:It’s a good one. Well, I think that’s all the time we have, les. Thank you so much for coming on. This was so interesting, but I’m sure we did not hit all of the points about spacesuits. There’s a lot more to this topic.

Les Padilla: My huge binder wasn’t used.

Host:So if you’re listening and you do have questions, make sure to submit them. Stay tuned ’til after the little ending music credits here, and then we’ll talk about where you can submit some ideas. And maybe we’ll do a spacesuits number two episode. Who knows. I’m sure there’s more we could talk about. So thanks again, Les, and stick around for more on spacesuits.

Les Padilla: Thanks for having me, Gary.

Host:No problem. All right.

[ music ]

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>> Welcome to space.

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Host:Hey, thanks for sticking around. So today we talked with Les Padilla about spacesuits. If you want to know more about everything spacesuits, just go to We’ve got a nice reference there for all different kinds of spacesuits, including the emus, mainly what we talked about today. Otherwise, you can go to to learn about everything going on aboard the International Space Station. And just this past month in October, we had three spacewalks, where astronauts were going out in the emus to conduct spacewalk and maintenance on the outside of the station. You can also find all this information on social media. So just go to Facebook, Twitter, Instagram. You know this, right? We talk about it all the time. International Space Station accounts on whatever social media platform you like– Facebook, Twitter, Instagram. On Facebook, International Space Station. On Twitter it’s @space_station and Instagram is @iss. And in the beginning, you can see that allyoop actually suggested the topic for this episode, and we’re listening to everything you have to say. So just use the hashtag #askNASA on your favorite platform, and submit an idea for something you’d like to hear about or a question you’d like to answer, or maybe you’d like to focus an entire episode on one specific topic. So we’ll make sure to look at those ideas and find the right person to bring on the show. Just make sure to mention it’s for hwhap– h-w-h-a-p– “Houston, We Have a Podcast.” This podcast was recorded on April 13, 2017. Thanks to Alex Perryman, John Stoll, and Matt Mackenzie. And thanks again to Les Padilla for coming on the show. We’ll be back next week.