IRA FLATOW, HOST:
This is SCIENCE FRIDAY. I'm Ira Flatow. Fifty-one years ago, on April 12, Yuri Gagarin became the first human to orbit the Earth. Hard to believe, it seems just like yesterday. Well, we have had five decades of experience of living in space. The International Space Station is still called home by astronauts. And there is still lots that we don't know, from the biological, how does living in space affect the human heart; to the agricultural, how do you grow plants so far away from Earth; to the quizzical, how does a flame behave in zero gravity.
These are just some of the questions that astronauts aboard the International Space Station hope to answer, and they're joining us on this anniversary to talk about what's occupying their time these days. Joining us from the International Space Station, NASA astronaut and Expedition 30 Commander, Dan Burbank; NASA Astronaut and Expedition 30 Flight Engineer Don Pettit. Welcome to SCIENCE FRIDAY.
DAN BURBANK: Got you loud and clear. Good to talk to you today, Ira.
FLATOW: That's great, thank you. We're very happy to talk to you. Let me ask you, Don, first: Does the view in space ever get tiring as you look out the window?
DON PETTIT: It never gets tiring to view Earth from space or space from space, just like any number of views from Earth, of Earth, never get tiring. To see a sweeping mountain scene never gets tiring. There's something about natural beauty that is inspiring to myself, and I will generalize to human beings.
FLATOW: What question do you get asked most, by people, besides the bathroom question? We'll do away with that one. What question do people want to know most about your experience in the space station?
PETTIT: One real common question is what I miss most from Earth, being up here for a six-month mission. And one real astute student asked me the inverse question: What will I miss most from space once I return to Earth? So I thought that was a very clever play on one of the standard questions that people ask you.
FLATOW: Dan Burbank, you were recently evacuated from the space station because of what turned out to be a close call with space debris. Give us an idea of what that experience was like.
BURBANK: Well, we actually had a pretty good heads-up about it. We've got tracking radars all over the world that keep track of orbital debris, and it's things that are basically, you know, in rough order magnitude about the size of your fist or bigger. And there are tens of thousands of things that are tracked.
And whenever one gets kind of close to space station, if we have ample time, we will actually move the space station, we'll actually do a burn - a debris avoidance maneuver, if you will - and it'll open up that distance to something a little bit more comfortable.
Every now and then we'll get something that's either small enough that it only crops up very late, or it crops up in such a way that the accuracy is a little bit unknown. And in this particular case, it was kind of a combination of both. There was a lot of uncertainty in it, and it was also very late. There wasn't time to actually do a born that would've been effective in opening up that distance to something more comfortable.
So for us, we talked about it the night before, actually probably a day and a half before, and we knew there wasn't time to do the burn, and certainly in the 12-or-so hours leading up to what we call the shelter in place, we discussed what we'd have to do.
And from our perspective here on board, it was actually fairly straightforward. We essentially started from the forward part of the station, worked our way back aft to where the Soyuz vehicles are located, and we powered down systems. We - and the ground did an awful lot of the systems work there.
And we closed all the hatches to isolate as many of the modules as possible from each other, and then we just waited until the closest point of approach with the debris item. And we were each in our respective Soyuz capsules.
FLATOW: There have been a couple of big solar flares recently that sent lots of potentially dangerous charged particles toward the Earth. What precautions do you have, do you have in the space station to shield yourselves from them? And are you in any real danger?
PETTIT: Earth's - we're outside of the atmosphere. So we don't have the protection from Earth's atmosphere like you would on the surface of Earth. However, we're still well within Earth's magnetosphere, and that deflects a lot of these particles so they don't pose a real threat. We do have a higher level of radiation up here, but we're still very much under the protection of Mother Earth.
And with very few exceptions, life just goes on normally on space station, with or without a solar proton event, and what we do notice, these events bring out wonderful displays of aurora.
FLATOW: Let's talk about some of the interesting experiments that you folks are doing up there, and one in particular that interests me is a flame experiment. We all know what a flame looks like on Earth here and how it behaves, but from pictures I've seen in zero-G, it looks totally different. And how are you experimenting with it?
PETTIT: Well, one of the racks, this rack right here, is a combustion rack for investigating various combustion processes, where you're looking at the nitty-gritty details of how flames burn. The rack right next to it is a glove box where I currently have a flame experiment set up there.
And basically flames have a healthy appetite for oxygen, and they get that oxygen literally by fanning the flame, and gravity helps fan the flame because of gravity-driven convection. The flame is hot. The hot air rises. Cold air rushes in, and that brings fresh oxygen next to the flame.
If you try to burn a flame in weightlessness with no air motion around it, it'll burn for a few seconds and snuff itself out. So the whole dynamics of what happens with flames is different in a weightless environment, and so the microgravity environment here on space station is a wonderful place to investigate fundamental aspects of combustion. It's basically another experimental knob we can tweak and help figure out what's going on when something burns.
FLATOW: And you're saying that if you leave the flame to itself, it will snuff itself out. That's - wow, that's something unexpected.
PETTIT: It is, and I was doing some combustion experiments where were burning little spheres of plastic, they were polymethylmethacrylate. It's the clear plastic that you see things made out of. And we were burning spheres of that, and we were going to - we had a fan blowing on it to add convection, and we were going to put the flame out by purging it with nitrogen, which would, should stop the flame.
It turns out it didn't stop the flame because the nitrogen entrained enough air in it that it just kept feeding sufficient to the burning plastic. And what snuffed the plastic out in a matter of seconds was turning the fan off, and the flame consumed all the oxygen around it, and it just went out on its own.
And I tell kids this is the space equivalent of what we tell our school kids of stop, drop and roll if you happen to catch on fire. But the space version of that is stop and float.
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PETTIT: And of course you don't need to drop because there's no place to drop to.
FLATOW: Very, very interesting. Let's talk about another experiment. Is it true that you have, like, a little distillery up there in space, you're doing a sort of a malt experiment? Are you going to brew some beer or something for us?
PETTIT: You know, I heard about that, but that experiment hasn't made it on space station yet, and I don't really know what the details are. I think it's just bringing some materials up and maybe mashing them and then bringing them back down to Earth. I don't think there's any plans for distilling.
However, we do have a distillation process here on space station, a distillation apparatus. And can you guess what we distill with it there?
FLATOW: I'm afraid to ask.
PETTIT: OK, it's part of what we call our regenerative life support system, which I like to refer to as the coffee machine because it consists of three pieces of equipment. We have a toilet. We have this big piece of equipment that the toilet is plumbed into, which contains a distillation apparatus, and then we have a galley.
And you go in and use the toilet, and then this big piece of equipment goes chugga-chugga-chugga-chugga, and then you go to the galley, and you get yourself a bag of coffee. And so I like to refer to this as a coffee machine because it takes yesterday's coffee and turns it into today's coffee.
And the key element, one of the key elements of that, is a fractional distillation process. And a normal process like that wouldn't work in a weightless environment because all our stills on Earth require gravity to separate the vapor from the liquid, and this uses a rotating body to help add centrifugal force to separate the vapor from the liquid and perform the distillation.
So it's really a neat piece of engineering research.
FLATOW: Very, very, very, very, very interesting to learn how that works. Don Pettit, you're going to be involved in the tracking and capture of Elon Musk's SpaceX commercial resupply ship, which is actually an historic event, the dragon capsule, in a few days. What's going to be your exact role, and are you looking forward to this?
PETTIT: The short answer to looking forward to it is yes. It's going to be really exciting to have a U.S. commercial-made unmanned vehicle come and rendezvous with station, and then we will lasso it with the arm and berth it to one of our common berthing ports. So that is going to be a real neat piece of technology plus the idea that we could have these vehicles come up and bring needed supplies.
So all of that aspect is really, really good. In terms of what we're doing to prepare, Andre Kuipers and I are going to be doing the robotics to lasso the dragon vehicle and then berth it to one of our ports. And I'll be flying an arm for the lasso part, and Andre will be flying the arm for the berthing to space station. So we're sharing the duties and backing each other up for this approach, attract and capture and then berthing to station.
FLATOW: Commander Dan Burbank and Flight Engineer Don Petit up there at the International Space Station. We're going to take a break and come back and talk lots more with them about research on the International Space Station. You can tweet in and talk about it @scifri. We'll be right back after this break with more conversation from space. So stay with us.
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FLATOW: I'm Ira Flatow. This is SCIENCE FRIDAY from NPR.
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FLATOW: You're listening to SCIENCE FRIDAY. I'm Ira Flatow. We're talking to Expedition 30 Flight Engineer Don Petit and Expedition 30 Commander Dan Burbank about experiments they're conducting. They're on the International Space Station, and it's the occasion of the 51 - 51 years ago, April 12, Yuri Gagarin becoming the first human to orbit the Earth.
Dan Burbank, what are you hoping to learn through your integrated cardiovascular experiment?
BURBANK: Well, that's an experiment that's got a lot of different aspects to it, and fundamentally, the main goal is to understand how humans adapt to the weightless environment of space and how we can mitigate the negative effects of that.
So for all of us here, you know, our bodies are just as strong as they need to be for the environment that we're operating in. So if we don't exercise, and we're on planet Earth, we will get flabby, and we'll lose muscle mass. If you're up here in space, and you don't exercise considerably, since you're never counteracting the force of gravity walking around as you would on Earth, up here you would lose a lot of muscle mass, you'd lose a lot of minerals from your bones.
Your heart volume, the size of the heart muscle would get smaller and smaller, and those would all be fine if you were going to live and essentially be a long-term creature of space. But since we're going to return to planet Earth, sometime, we'd like to minimize that as much as possible.
So integrated cardiovascular kind of looks at a holistic - in a holistic way at how the body adapts to here, and we do everything from ultrasound, where we're scanning our hearts and our blood vessels. We've got a lot of exercise components to this. We're doing blood pressure and 24-hour, actually 48-hour electrocardiogram to understand how, from an electrical standpoint, how the human body is changing.
And all these things will help us leave low-Earth orbit and go on into deep space, to go back to the moon long-term and to go on to the asteroids and Mars. And I think that's a key part of what space station can do for us.
FLATOW: I had heard that there had been some talk at NASA, I was reading about it this week, and maybe you can talk about it, about using the space station as a simulation for going to Mars, a sort of a long-term, simulation mode of what the trip would be like and how it might affect your body. Can you talk about that at all?
BURBANK: Yeah, there's a lot of discussion about it right now, and that's a really interesting part of it. You know, one thing that's fundamentally different about what we do here on space station and our experience here on space station from what it would be like to go to the moon long-term and certainly to go to Mars.
Now, rough order of magnitude, the moon is about 1,000 times further from the Earth from the space station. Mars is about another 1,000 times further, you know, than the moon is. So you've got a lot of different aspects to what it's like to leave the close confines of planet Earth.
Here, we essentially have a permanent logistics stream from Earth. If something breaks on-station, as, you know, all too frequently will happen, we've always got the ability to fly new parts. If you're going to the moon, and you're going to be there long-term, or if you're going to Mars, you can't do that. You're going to basically rely on yourself.
Now, the psychological aspect of going to Mars, there's another whole wrinkle to that, and that is the time it takes to transmit a single from Earth to the crew on Mars or vice versa, and you're limited by the speed of light, and it'll be a long, long time. Earth will become vanishingly small. It'll almost be, you know, be indistinguishable from a lot of the brighter stars. So you'll feel very remote.
So the psychological part of it would be kind of an interesting thing. To simulate that on-station, that would probably involve essentially introducing a time lag between when the crew calls the ground and when the ground responds. It would involve, you know, potentially limiting the crew's view out the window. And so you're not seeing planet Earth, you don't feel physically as close to it.
And it might involve even going so far as to letting the crew deal with emergencies and system malfunctions and work their way through them to a greater and a more independent degree than we currently might on space station. And there's a lot of discussion about how you might do that.
It might be something that would be applicable, but I don't know yet about any immediate, near-term, concrete steps in that direction.
FLATOW: Having lived - I'll address this to both of you. Having lived up there for many months, and having prepared so long for your voyage and your life in the space station, what did you find that you were not quite prepared for? What are some of the unexpected things?
PETTIT: That's a good question, and I've got a little example, one of these small details that you can never train for, and you are just surprised when you come up to orbit that it could be this way. And it has to do with our trash cans, our waste baskets. And we have these really nice wastebaskets, and if you open up the lid to put a small piece of something in there, that little small piece of something will just be floating right under that lid.
And then the next person who opens that lid up, all these little small pieces come floating out, and it makes a big mess. And so the waste baskets are great for a big chunk of something, but all these little tiny things, like little pieces of tape and little strings and things like that, you don't want to put them in the waste basket or they just make a mess for the next guy.
So what we do is we take one our little wet-wipe containers, which is just like the wet-wipes that you use for wiping baby bottoms on Earth, and we use the same ones up here, and they come in a little plastic pouch with a little lid, a little doorway that you can open up.
And when we have one of those things empty, we stick it on the wall, and we use it for a small-items wastebasket. And you can open that little lid, and you can put little tiny things in there and close the lid, and you don't need to worry about all of these things swimming out.
And I never would've thought that you'd use something like this for a little trash can, and it's an elegant solution to the problem. And these are the kinds of things that you only learn once you show up in space.
BURBANK: Yeah, I guess if I were to think back on the thing that probably surprised me the most, you know, even having been up here twice on shuttle missions, is how difficult it is to keep track of everything that you have. On a shuttle mission, it's a little bit smaller volume. You do spend time in the station.
But you don't spend as much time here that you don't get necessarily exquisitely good about keeping track of things. And up here, you know, the first couple of weeks that we're around, it is so easy for things even that are Velcro-ed and attached and so forth to just fly away, get bumped and jostled.
You know, we joke about, you know, new crews coming onboard space station, shuttle crews included, creating a wake of swimming parts and cameras and notebooks and procedures and so forth behind them when they go by.
It gets to the point up here where everything that you do, you're constantly thinking, planning - or at least in the back of your mind - how to keep track of everything. And if you're going to take something apart to fix it, for example, keeping track of bolts and washers and nuts and having a little piece of tape staged by and having all your tools organized is something that's kind of part and parcel with your life up here.
FLATOW: One last question: Dan Burbank, you're going to be coming back in a few days. Is adjusting to life back on Earth going to be difficult? Are you looking forward to it, or are you going to be nostalgic about missing the space station?
BURBANK: I think everybody that's had a chance to be here, I think you're always going to have just a little piece of your heart that's still here, that you're going to miss these views, miss just the nature of life in space. I'm really looking forward to seeing my family again. Family and friends, being able to see them again, will be great.
The thing that'll be really hard, at least by all reports, is getting used to planet Earth's gravity and getting used to fighting it all the time. We spend a lot of time exercising up here, but I wonder if it'll ever really be enough to make those first couple of weeks as easy as I hope they would be.
FLATOW: Well, Commander Burbank and Flight Engineer Don Petit, I want to thank you both for taking time to be with us today, and good luck to you, and welcome back when you get back to Earth. Thank you for joining us on SCIENCE FRIDAY from the International Space Station.
BURBANK: Ira, thank you, it was great talking to you today.
FLATOW: The full interview with NASA astronauts Dan Burbank and Don Pettit is available via podcast, or you can download it from our website at sciencefriday.com. Transcript provided by NPR, Copyright NPR.