Spacewalk fixes leak on the International Space Station

TWO American astronauts have been celebrated for finishing their weekend chores after they went on a spacewalk to replace a leaking pump on the International Space Station.

Chris Cassidy and Tom Marshburn completed the work an hour ahead of schedule, in an effort to stem an ammonia leak from the station's cooling system.

The BBC reported the crew spotted particles of ammonia drifting away from the laboratory on Thursday.

Nasa said the crew were not at risk but managers wanted to solve the problem before Mr Marshburn returned to earth.

He is due to return to Earth early next week along with the space station's Canadian commander Chris Hadfield and Russian cosmonaut Roman Romanenko, after six months in space.

Ammonia is used to pull heat from electronic systems, which is then dispersed into space.

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