Transcript for NASA Officials Explain Emergency Spacewalk Plans
This is a special room. Hello I'm tired and is in New York with his ABC news digital special report it could be an unforgettable Christmas for the astronauts on board the International Space Station. NASA says two astronauts will perform emergency spacewalks this Saturday and if needed on Monday and Wednesday as well. Space walks are usually planned months in advance but this what is happening urgently because of immediate repair is needed to the international space station's cooling system. NASA is currently giving a news conference about the space walks let's have a listen. The pump. On 01 or external coolant loops was shut down an issue as you may recall the ISS has to. -- large ship coolant loops on now both the star -- -- port side. That we prefer -- courses aimed be for lack of creativity in naming. And the pumps cool. External or use as well as the heat exchanger. That exchanges -- with the Waterloo inside and -- the internal components on space station and we do that. Because ammonia is a highly toxic substance and we don't want it to be inside the vehicle and so that's why. We keep -- on the outside in the water on the inside. Though of course the one area where you have a risk that she could introduce ammonia -- into the -- -- and therefore eventually into the into the environment inside space station is through the heat exchanger and so we go to great pains to protect. -- a freeze in the water forced the water expands and you could fracture of the heat exchanger and -- the -- get into the Waterloo. And so we have a number of systems that protect us from that. So -- of last week at some point as as the cool loop was trying to manage. The temperature of the ammonia. It got to the point where it the temperatures. Were remaining at colder than it expected and so the -- was shut down. As expected in the system reacted the way -- -- the system to react. And this was caused by a offset or bias -- and will refer to as the flow control valve. Well this is the valve that manages the flow of ammonia either descended through. To the radiators or or as one extreme completely -- the radiators or another extremely call bypassing the radiators. Where the majority before actually goes around the radiator back to the pomp and this is how -- control the temperature. It turns out that. We had a failure of of the flow control valve. Probably the electronics in the flow control -- Which makes the -- think it's gone to a completely coat closed state when it actually hasn't reached that. And preventing us from fully closing the the valve then -- is popular warm -- the ammonia -- level we need and depending on. The environment we in the -- where they're out in other loads on their you can get to a point where they ammonia itself it's too cold to -- the heat exchanger. And so. We have spent. The last week things Wednesday was so we spent about the last week trying to figure out ways to either recovered that. That valve or find other ways to managed loads on the outside so we can keep the temperature below freezing. Coming into the heat exchanger but also the same time though -- -- can't be too high or doesn't do the cooling function is supposed to provide. The ops and engineering teams have done them just an amazing job -- sort through all kinds of options to try to recover the valve. And look at other ways to manage the flow over the last several days. Since we could not for her out a way to actually repair. The -- over command the valve. To overcome this bias. We start working on a valve. And isolation valve that's just upstream of the flow control -- and looking to see if we can use it to manage the flow. We have tried to commander from the ground. Can do to latency in other factors we had a hard time managing the flow. At the level in the repeat ability. That was necessary. And you know this -- notice couple -- -- to pump. Shut down that was part of -- trying to managed loads in and us and really struggling with it. And so the last thing that we've -- on board as we created a command. -- that we sent on board and so when the ground commands this patch. It's done in such a way basically it was taken the latency out of that -- didn't out of the commanding sequence. And -- we found that we do have. A way to repeatedly. Move this valve around. So now we've done that we're trying to figure out how to introduce loads and see if we and indeed can manage. I'm not only -- nominal scenarios but the oft com listeners and in the ground continues to do that. Com meanwhile as you know we've been marching towards the launch of -- the first or CRS mission orbital CRS mission to ISS. That was scheduled to launch here on the nineteenth. And we had been trying to see if we can get to the point where we could reliably manage. The flow of the ammonia so that we can rely on this -- In the event of the next worst failure of the next were spared course of the loss of blue B. And in doing the work in trying to figure that out we've. We carried both scenarios both of -- there were left over will -- because we've managed salute to the point that we. We think we've we've got ourselves to -- we think you can control -- well enough to handle the next barrier. And and loud or we'll come up we get on the other side of the of the beta -- -- we have a very high. Beta angle period that occurs always around this time a year. That we that we go into it about December 30 and so we were trying to get ourselves in the position where either we -- -- come up when we're able to control the flow. And then replace the -- or -- we can't reliably. Figure out how to control. Of the system than we would go ahead and asked -- folks stand down and they're going to deviate done. So we sort of reached that point yesterday yesterday afternoon -- we we realize that. -- it if we continue to press. We're we're starting to two point we have to pick one -- of the other -- take it to crew ready we have to -- the ground team focused. And and if we focused on flying orbital and found. That we couldn't control. The flow even if we thought we were going to be successful if we weren't we'd lost the opportunity -- being changed up the -- before the -- cut out. And so -- shows that. That the Bahrain will have NASA officials there really is in on the nitty gritty of some space -- needed. To secure and to fix a very important cooling system on the International Space Station -- -- David Alexander director at Rice University space institute to tell us more. On -- on what's being talked about now with NASA and how. The astronauts are gonna try to resolve this problem and how dangerous it could be this is classified David as an emergency spacewalk. -- want to -- -- usually have to prepare for such a thing. Well usually before before any expedition theirs this manifests of what the astronauts who want to do over the course of -- six months have typically don't. That in the planned appear appear on the via a piece of equipment to the need to install -- so we'll have -- space walks arranged many months and at times services. I'm -- rather rapid turnaround. So how does -- complicate things now that it is a rapid turnaround and have we heard anything new. -- from the folks at NASA when they when there's just spoke today. I think I mean obviously. There's a lot of skilled technicians working on with -- experience of -- -- space walks TVA's. So I don't think -- much danger in this in. Having a so quickly if there -- was a colossal into the taken number of days they know whether during. And the on this appear before so -- some experience in the war takes and so I'm not too worried about it the fact that they had to do this. In a few days as opposed to a few months. There is an emergency is spacewalking not in the sense there wasn't planned and -- to six very important problem. We know about the two astronauts selected for this mission. Well as a lesson MB three and falls to begin the space walks around -- -- stretch he always veteran space walker the -- -- on six TVA's in and it is -- experience. And my Calkins is is -- to the space walks but he's a very accomplished astronaut he's very well trained. My friend to make it must mean who says he's really good in the tool which is whether do all their spacewalk training so. And they've already practice this true I'm on the ground there in the in the swimming through. Announced illustrator Paris so so you I think they're very accomplished this -- astronaut courses a Japanese astronaut example which is part of the crew complement. -- -- -- And -- be controlling their bought to armed it to -- news -- killing pumped out from a storage location outside the space station. I'm -- -- that the -- replacing the old one with -- new. So we know astronauts must live for this moment because so few of them ever get to do something like this literally. Walking in space are venturing out into space but what are some of the dangers of. Well I sure most of whom watched the movie gravitating Ahmanson less secure an extreme thing that can happen. You know you have to remember that that you're basically. They're the massing of all of the elements -- So lots of them back to meet your race -- flying by in and say they're living facility and costs as a miles an hour. And what's protecting them from the environment is that space submit to you if you whereas -- -- mylar and some -- to submit shields and so it is it's not a walk in the park is something you have to be very careful. You have to make sure all your safety procedures have been fold down in place so. Yes -- exciting look at it myself -- it down. But it does come with some risk. And I -- a refresher here how many people are currently living on that space station. What are what are living conditions like there and and how essential is this cooling system to their dearly survive -- Whether a six. Astronauts cosmonauts on -- three russians' -- Americans and Japanese. And the moment everything's fine I'm in massacres and redundant systems so you've got to talk about loopy and -- he. So everything was being in control it and the temperature was being regulated by -- -- and ask whether the problem ball -- -- -- -- switched. Most all of the equipment and -- -- Controls to -- -- which can handle mostly to launched what they've done -- this as an extra precaution courses turned on some. Nonessential equipment. Salute so as far as the astronauts are concerned the environment that they're living and -- the the temperature control -- stool. What they're expected to be assists as normal conditions. Out there will like to think about it is you know to -- you bought redundant systems Hawaii. Why worry about the the one that went bust. Com and race you can operate and one kidney it's always nice to two. And NASA likes to have those back -- systems so this is a very important repair for the continued presence of all the astronauts on station. And once these space -- are all wrapped up also and then what kind of told they take on the body in terms of the astronauts did they need to recover from -- No I think I think I mean to go -- one thing that it is that a little bit different news. It's been so long -- is basically on the job and that believes -- space walks are six and half -- us. Sometimes it can -- as long -- -- -- so the solo olds you know loss fatigue comes from just working. Now I'm sure -- terrace street six -- our street. And do pretty micro gravity environments that seems so they can a long term. Affects. Are. No different. One thing you may worry about although I don't think that's the case here is that you are -- unprotected from an east -- storms that might happen. And there's this station provides some bad shooting from not. And not so what to -- very very closely for instance -- council. A spacewalk -- Solar activity picks up although poses an imminent threat of -- slayer for example. All right what -- what -- thing to have to worry about. Just a day on the job I want to thank you so much David Alexander for joining us of the Rice University space institute happiness. Figure they sell out he could have Chris get a complete recap right here on abcnews.com. And if you would like to continue watching. That NASA news conference live updating us on these emergency spacewalk that will continue streaming here. On abcnews.com as well for now I'm -- Hernandez in new York and this has been an ABC news digital special report.
This transcript has been automatically generated and may not be 100% accurate.