This is For the Record.

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WILLIAM SHATNER: Space.

TOM HANKS: Houston, we have a problem.

UNIDENTIFIED ACTOR: Astronaut is awestruck.

SANDRA BULLOCK: What do I do?

SHATNER: The final frontier.

MATT DAMON: I'm going to have to science the [expletive] out of this.

MARTIN: Most of our ideas about space come from movies - or maybe your third grade trip to the planetarium. Today, you can log on to NASA's website and watch live feeds from the International Space Station, a real-life space adventure.

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SCOTT KELLY: Let me just get my bearings here. I'm looking at the moon out there.

MARTIN: At this very moment, astronaut Scott Kelly is on month eight of his year-long stay on the space station. This past Friday, he and Kjell Lindgren made their second spacewalk. What's important to remember here, they were outside the space station when they did this, tied only with a tether, floating in outer space.

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KELLY: I can go do it. I'd prefer to do it if you guys are OK with it.

MARTIN: Their assignment was to configure a vent door on the port-side ammonia tank.

TRACY CALDWELL DYSON: OK Scott, we're going to take your lead. We're happy to have you go and do that.

MARTIN: Today, we hear from three astronauts about this very particular space experience. For the Record: Walking in Space.

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KELLY: How does that look there, Tracy? Do you see that?

CALDWELL DYSON: I can see it. And that looks good, Scott.

MARTIN: That voice on the other end of the line is Tracy Caldwell Dyson. She's watching a feed of commander Kelly's spacewalk from Houston.

CALDWELL DYSON: I am totally in their air - I mean (laughter) to an annoying degree, probably.

MARTIN: On October 28, Scott Kelly and Kjell Lindgren were out on their first spacewalk, and their only connection to Earth was Tracy Caldwell Dyson. She was the NASA astronaut in Houston giving them directions.

CALDWELL DYSON: It's nice when you have someone that's done it before because then they can, you know, relay experiences or at least speak to them in a manner that they know that they would want to be spoken to.

MARTIN: She knows what it's like because she's been there. She's done three spacewalks herself. She's a member of a small group of people who've had this experience, not just going up into space but actually floating around in it.

TERRY VIRTS: I've flown jet fighters and been a test pilot. And there's a lot of things I've done in my life. But I had never - there's nothing like spacewalking.

MARTIN: This is Terry Virts. He's been on two spaceflights, and he's done three spacewalks. Before you get to float around in the atmosphere, there's a lot of training, as you'd expect. Much of it happens in a huge swimming pool at the Johnson Space Center in Houston. It's the closest you can come to simulating the experience. Here's Tracy Caldwell Dyson.

CALDWELL DYSON: You know, we take it for granted in the pool here where we train that we don't have to have a death grip. But when you're out in space and you realize there's no tether other than the one that you've attached to structure - there's no diver floating around to keep you safe - and you just see this planet beneath your feet going 17,500 miles per hour, and you and the other person in a puffy white suit are the only two out there in the vacuum of space, you tend to hang on a little tighter.

MARTIN: And that puffy white suit is really heavy.

VIRTS: The spacesuit itself weighs about 400 pounds on Earth, and it's pressurized. And so what looks like a big, thick, bulky, you know, winter parka - when you pressurize it, that material becomes like steel. And so moving around in this spacesuit, just to move your arm requires physical exertion.

MARTIN: Tracy Caldwell Dyson remembers her first spacewalk clearly.

CALDWELL DYSON: I had to go out the hatch and go immediately on top of the crew lock. And when you go on top of it, you are basically looking behind the space station at the aft end, we call it. And there's nothing - no structure in your view. And you just see the earth. And I'm up there, and, you know, even though I've got, you know, probably 50 handrails all around me that I can hang on to and I've got a hook - a big hook from my waist to structure so I know about going anywhere - it was still one of those breathtaking moments where it's like, whoa (laughter).

MARTIN: Those moments of reflection are rare. These spacewalks can take more than seven hours, and they demand intense, focused concentration.

VIRTS: Ninety-nine-and-a-half percent of your time - my time on my spacewalks, I can say - was completely focused on what was going on. I felt not rushed, but pressed every second that I was outside. Like, there's no time to stop and look around. There's no time to take pictures. There's no time to do anything other than - you got another task going on because you don't want to spend extra time outside.

MARTIN: Because things can go wrong.

LUCA PARMITANO: My name is Luca Parmitano. I live in Houston because I'm an astronaut.

MARTIN: Two years ago, things did go very wrong for this Italian astronaut. Early on in his spacewalk, he felt water on the back of his head.

PARMITANO: And I knew that something was not right.

MARTIN: There was a leak in his helmet. Parmitano didn't want to tell ground control in Houston. He knew they might cancel his spacewalk. And at that moment, he really didn't think it was a big deal. But he told them anyway.

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PARMITANO: I feel a lot of water on the back of my head.

SHANE KIMBROUGH: Are you sweating? Are you working hard?

PARMITANO: I am sweating. But it feels like a lot of water.

That is when things went really south. The sun went down. And when the sun goes down on an orbit, it is not like one of those beautiful sunsets. It lasts only a few seconds. One second you have light, and the next you have no light whatsoever. It is complete, utter blackness. And at that moment, I was also upside down. And that's when the water covered my eyes, my ears and my nose.

MARTIN: A liter and a half of water had flooded into his helmet. It came from the cooling system in his suit. Water acts differently in space. It forms a goopy kind of gel that sticks to your skin.

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KIMBROUGH: Hey Luca, can you clarify - is it increasing or not increasing?

PARMITANO: It's hard to tell, but it feels like a lot of water.

MARTIN: Pretty quickly, that water disabled Parmitano's communication system.

PARMITANO: I couldn't hear anything anymore. I couldn't see anything anymore. And I couldn't breathe through my nose because my nose was filled up with water.

MARTIN: He could still breathe through his mouth, but he couldn't see. Slowly, he felt his way along the surface of the space station in the direction of the airlock. When he finally made it back, his partner on that spacewalk, Chris Cassidy, radioed to Houston that Luca was fine - miserable, but fine.

Has this changed your ambition? Has this changed your desire to go back up in space again?

PARMITANO: Well, I was - I wanted to go out the next day.

MARTIN: No matter the risk, it's hard for astronauts to call it quits. Here's Tracy Caldwell Dyson.

CALDWELL DYSON: It's my hope that I get to go again. But we have so few flight opportunities, and we have new people that haven't flown once, even. And so you need to give everybody a chance to get up there and get that experience.

MARTIN: NASA ended its shuttle program in 2011, which means when NASA sends astronauts into space, they ride on small spacecraft operated by other countries. Astronauts just don't have as many opportunities as they used to.

VIRTS: The flights that you've had are fine, but the only flight you really care about is your next flight.

MARTIN: Again, this is astronaut Terry Virts.

VIRTS: I can remember watching the sun rise, which is just spectacular. It reaches from one side of the horizon to the other. It's a long, thin blue-orange band. And I just remember, you know, almost hearing from God sitting there, thinking about creation. It's almost like you're in some secret room, seeing something that, you know, humans weren't meant to see or something. It was kind of a glance into the forbidden view.

MARTIN: Astronauts Terry Virts, Tracy Caldwell Dyson, and Luca Parmitano.