One of the station's two external cooling loops, known as Loop-A, shut down when it reached a pre-set temperature limit on Wednesday, Byerly told NBC News. That forced NASA to reroute coolant into Loop-B. As a result, the station's six-person crew had to prioritize life support systems, electrical systems and science experiments — including the freezers that preserve scientific samples. Some non-critical systems were turned off in NASA's Harmony node, Japan's Kibo lab and Europe's Columbus lab.The article indicates that the failure is one of the "Big 14" failures that are failures anticipated to occur over the lifetime of the station.
The crew "worked to keep the freezers going," Byerly said.
Engineers think the problem was caused by a malfunctioning flow control valve for the station's ammonia coolant. Mission managers are trying to determine whether a software fix can get the valve working again, or whether a spacewalk will be required. Sorting through all the issues might take a couple of days, or as much as a couple of weeks.
Thursday, December 12, 2013
Cooling System Failure on International Space Station
From NBC News: