14 DAY TRIAL // Two ISS astronauts, Chris Cassidy and Tom Marshburn, are preparing for an extravehicular activity (EVA) or a spacewalk, to try to assess what is causing the ammonia leak that has been spotted recently.
NASA has a pretty good idea of what's happening, a pump system that has caused problems before is the probable cause of the leak in the cooling system for one of the solar arrays.
The astronauts are now preparing for the spacewalk, which takes several hours, and they will then walk out and go to the area of the ISS where the Pump Flow Control Subassembly is located.
They will inspect the problem area and replace the subassembly with a spare one that is bolted on close to the location of the problematic one.
Once the spare part is in place, the astronauts will inspect each other to check for ammonia ice on the suits and head back to the ISS airlock. All in all, the entire procedure will take several hours, assuming everything goes well.