NASA has revealed that two US astronauts have successfully repaired a critical cooling system pump at the International Space Station.
Rick Mastracchio and Mike Hopkins completed a spacewalk of 7.5 hours to replace the faulty ammonia pump, the BBC reported.
The pump broke down two weeks ago, leaving the US side of the station without half its cooling system.
All non-essential equipment had to be switched off and many scientific experiments were halted.
NASA now says all the systems should be back up and running by the weekend.
It was the two astronauts' second spacewalk in three days to replace the pump, which is about the size of a refrigerator.