A series of spacewalks might be necessary to fix a breakdown in the equipment cooling system aboard the International Space Station, NASA said Friday.

A US space agency spokesman told AFP that NASA will decide by Monday on the appropriate measures to fix the breakdown, which has posed no danger to the six-man crew.

"Station program managers will have further discussions on potential contingency spacewalk planning that could result in multiple spacewalks to replace the pump module beginning as early as late next week," said a NASA statement.

NASA is also expected to decide by Monday on whether Orbital Sciences' maiden launch of its Cygnus unmanned cargo craft can go ahead as scheduled on December 18.

The cooling problem occurred Wednesday in a flow valve that controls the temperature of the equipment aboard the station.

Engineers on the ground have been trying to fix the issue, but a spacewalk might be necessary to get a closer look at the external thermal control loops -- of which two exist on the station -- and the defective valve.

The astronauts have the necessary equipment on board the ISS if a replacement of the pump is needed, NASA has said.

A temporary fix is in place in the meantime, in which some equipment has been shut down to save power.

A similar equipment failure in 2010 required three spacewalks to fix.

If spacewalks are called for this time, they would mark the first time astronauts have ventured outside the orbiting lab since a helmet leak brought an early end to a European astronaut's outing in July.

Italian astronaut Luca Parmitano was wearing a US-made spacesuit when a water leak flooded his helmet and risked drowning him.

NASA has not yet announced the results of an investigation into what went wrong with his spacesuit.

There is a planned spacewalk by two Russians on board the station for December 27.

Commander Oleg Kotov and Flight Engineer Sergey Ryazanskiy are slated for an outing to install cameras and other equipment on a platform outside the Russian segment of the station.