NASA plans possible spacewalks to fix space station cooling system

Last Wednesday, an urgent situation arose when the cooling system of the International Space Station suffered another failure, and after working through potential solutions from the ground, NASA is now making plans for some potential spacewalks to fix the problem.

The failure happened early Wednesday morning, when one of the pumps that feeds liquid ammonia coolant through the exterior cooling loops reached a temperature that set off a pre-set safety limit. This caused 'cooling loop a' to shut down, and 'cooling loop b' automatically took up some of the slack to compensate.

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The International Space Station has two independent cooling system loops, which run coolant through the station's interior electronics, collecting waste heat and then out along the station's exterior to vent that heat into space. Although a failure in the system is not life-threatening to the crew members on board, without a working cooling system, the station environment would quickly become unbearable. In this case, with only one side of the loop malfunctioning, the crew only needed to shut down some non-critical systems and station sections, in order to reduce the load on cooling loop b while the repair attempts are made.

Engineers on the ground were able to trace the problem remotely, and found that it was a potentially-faulty valve inside the cooling pump. They have been working on the system since, adjusting the valve's position, as well as adjusting other valves and settings on the pump, to see if they can get the system working again. However, there has apparently been no success as of yet, so now it turns to the crew members to possibly venture out on a spacewalk to make repairs.

According to NASA, the first spacewalk could happen as early as Thursday, December 19th. If they go ahead with that plan, it would likely delay Orbital Sciences' first Cygnus resupply mission, which is scheduled to launch up to the station at 9:19 p.m. EST Thursday.

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It should be noted, although ABC News emphasizes the "dangerous" aspect of these spacewalks, there is nothing inherently dangerous about the repair attempt itself. It's just that venturing out into space, even in a spacesuit, is always a dangerous operation. It doesn't need to resemble what happened in the movie Gravity. Just take Italian astronaut Luca Parmitano's harrowing experience back in July. Water began to leak into his helmet, and due to the strange way that water behaves in zero-g, the 'pool' of water that formed began to surround his head. If he hadn't returned to the station before it completely covered his face, he could have drowned in just a centimetre or so of water.

NASA astronaut Douglas Wheelock said it in the video: "Whenever we open that hatch, and set people outside, it's always dangerous."

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