Washington, DC, United States (4E) – NASA astronauts Rick Mastracchio and Mike Hopkins completed the repair of a broken ammonia pump module outside the International Space Station (ISS) after more than seven hours of spacewalk on Christmas Eve.
Mastracchio and Hopkins removed a spare ammonia pump module from the space station’s External Stowage Platform-3, bolted it to the starboard truss and connected it to Loop A of the station’s external Active Thermal Control System.
Once installed, they connected ammonia fluid lines from a jumper box to the newly installed pump module restoring ammonia flow for the ISS’s cooling system. The module circulates ammonia through loops outside the station to keep equipment cool.
The astronauts encountered only a minor issue during the spacewalk that ended at 2:23 p.m. ET Tuesday. Ammonia flakes were released while they untangled fluid lines and it landed on their space suits.
It was the second spacewalk of the two astronauts to continue the repair of the broken ammonia pump module started on Saturday. The ammonia pump malfunctioned on Dec. 11 when an internal flow control valve got stuck in an incorrect position. The malfunction prompted the ISS crew to cut back on operations and prioritize cooling of the space station’s life support system.