About 2 1/2 hours into today’s spacewalk, astronauts Chris Cassidy and Tom Marshburn of NASA removed the 260-pound pump controller box that may be the source of an ammonia leak from the P6 truss of the International Space Station and replacing it with a spare that had been stowed nearby on the port-side truss, or backbone of the space station.
So far, the spacewalking duo has not found any indication of where the ammonia leak originated.
Ammonia is used to cool the station’s power channels that provide electricity to the orbiting laboratory’s systems. Each solar array has its own independent cooling loop. This ammonia loop is the same one that spacewalkers attempted to troubleshoot a leak on during a spacewalk on Nov. 1, 2012. It is not yet known whether this increased ammonia flow is from the same leak, which at the time was not visible. It is anticipated that the 2B power channel, which is one of eight power channels to supply electricity for station systems, will be depleted of ammonia coolant by late this morning and was shut down yesterday as ammonia levels reached the low limit for pump operation.
About 2 1/2 hours into today’s spacewalk, astronauts Chris Cassidy and Tom Marshburn of NASA removed the 260-pound pump controller box that may be the source of an ammonia leak from the P6 truss of the International Space Station and replacing it with a spare that had been stowed nearby on the port-side truss, or backbone of the space station.
