Transcript for International Space Station Cooling System in Partial Shutdown
Now we want to tell you about the breaking news on the international space station, word of trouble that could require quick action and even emergency walk in space. There are six astronauts on board including two americans. Abc's clayton sandell has what we know at this hour. Reporter: Tonight nasa is considering an emergency space walk to fix part of a critical cooling system on the international space station that may be failing. Severe temperature fluctuations in something called a heat exchanger. Think of it like a radiator on your car indicating there is a problem. Engineers do not know what's causing it but the only way to physici fix it may be a space walk. If it can't be fixed astronauts on board may have to shut off parts of the station and in a worst case scenario may have to evacuate the station completely. Right now there are six crew members on board the station, from the u.S., Japan and russia, the most recent arrived in november and were supposed to stay until march of next year, but tonight engineers are working overtime to try and make sure they can complete their mission. Clayton sandell, abc news, denv denver. Abc news will be staying on this tense word and also the full story throughout the night as it develops.
This transcript has been automatically generated and may not be 100% accurate.