NASA Discusses Details of Spacewalk to Fix ISS Coolant Leak

Image Credit: NASA
Image Credit: NASA

The Expedition 35 crewmembers and International Space Station (ISS) ground controllers are working on plans to conduct an Extra-Vehicular Activity, or EVA, in hopes of correcting an ammonia leak on the space station, said NASA managers in a press conference today.

The leak was discovered yesterday as flakes were visually observed (characterized as “ammonia snow”) trailing from the P6 (“P” meaning “port”) Truss Worksite in the 2B Photovoltaic Thermal Control System, which helps cool one side of the space station’s solar panels.

A leak was observed in this section in November 2006—then, as now, it required an EVA to resolve the situation to the same coolant loop. The initial repair seemed to hold. However, yesterday the leak rate skyrocketed to approximately five pounds a day. This would deplete the system by day’s end tomorrow. NASA is not sure if the two leaks are related.

International Space Station Manager Michael Suffredini discussed what appears to be the origin of the leak; it is believed the leak is coming from the 2B Pump Flow Control Subassembly (PFCS). The pump has been shut down, as if it ran out of ammonia flow it would start to “cavitate” (meaning it would begin to take in air which would damage the unit beyond repair).

NASA astronauts Chris Cassidy (EV1) and Tom Marshburn (EV2) are currently preparing to conduct the spacewalk. Part of their role will be to observe where the exact location of the leak is originating from and then to conduct necessary repairs. Station managers and the space station crewmembers are currently working on preparations for the spacewalk. Astronaut Terry Virts and the European Space Agency’s Samantha Cristoforetti have been working at the Johnson Space Center’s Neutral Buoyancy Lab located in Houston to aid in preparations for potential repairs.

While this leak is serious, since it would affect the ISS’ power supply, the crewmembers were reported to be excited about making the EVA and in good spirits. NASA has stated that they are in no danger. ISS commander, Col. Chris Hadfield, positively tweeted: “Good Morning, Earth! Big change in plans, spacewalk tomorrow, Chris Cassidy and Tom Marshburn are getting suits and airlock ready. Cool!” Suffredini emphasized that redundant power systems mean that the ISS will continue to be powered and “do what it was intended to do.”

Stay tuned to AmericaSpace for more information and for updates about the spacewalk, which is planned to take place tomorrow.

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