NASA has decided that two American astronauts will conduct a series of space walks, starting this week, to fix a broken cooling system on the International Space Station (ISS).
One of the station's two ammonia cooling systems shut down last Wednesday, forcing astronauts to power down unnecessary equipment and suspend some of the laboratory's science experiments.
NASA says the six-member crew if the ISS is not in any danger. But after engineers on the ground failed to devise ways to bypass a faulty valve inside the pump, located outside the station, the U.S. space agency decided to have the astronauts replace the pump.
Flight engineers Rick Mastracchio and Michael Hopkins will begin the repairs on Saturday. Two more spacewalks are scheduled for December 23 and December 25.
The repair work has delayed a cargo flight planned for Thursday.
The station crew includes three Russians and one Japanese, aside from the two Americans.