NASA announced on Sunday that it was considering spacewalks, or a resupply mission, to fix a cooling loop on the International Space Station, which was affected by a malfunction on Wednesday of a flow-control valve in a cooling pump.

The pump module on one of the space station’s two external cooling loops, which are responsible for circulating ammonia outside the space station to keep both internal and external equipment cool, automatically stopped working on Wednesday when it reached a pre-set temperature limit. The anomaly forced astronauts to power down non-essential equipments, suspending some of the space station's science experiments.

While engineers continue to assess the situation, examining techniques to position the valve better and additional ways to manage the temperature on the malfunctioning loop, NASA is also looking at two other possible moves to address the issue. 

According to NASA, flight engineers on the ISS, Rick Mastracchio and Michael Hopkins, began preparing their spacesuits in case spacewalks were required beginning Thursday to replace the damaged pump. 

"The biggest challenge on this spacewalk, in my opinion, is the large fluid connectors that are connected to the pump module. But of course, we have a lot of tools if we have problems with those to fix that,” Mastracchio told Reuters.

The space agency is also preparing to enable Orbital Sciences Corp., (NYSE:ORB), a Dulles, Va.-based satellite manufacturing company, to launch its Antares rocket and the Cygnus cargo craft from the Wallops Flight Facility in Wallops Island, Va., Thursday night at 9:19 p.m. EST on its first resupply mission to the space station.

The space agency said it has kept both options on the table pending further engineering analysis and troubleshooting efforts on the station’s cooling system.

"It's a serious problem, obviously it's something we have to fix," Reuters quoted Mastracchio as saying during an inflight interview on Friday. "It's not something I'm worried about, though.”

In 2010, a failure occurred in the same pump, and was fixed by the help of three spacewalks, and according to NASA estimates, the latest glitch could also require the same to complete the repairs.