Astronauts May Take Emergency Spacewalk to Fix Space Station Leak

International Space Station as seen from NASA space shuttle.
This image from a NASA space shuttle mission shows the International Space Station in orbit. The space station is the size of a football field and home to six astronauts. (Image credit: NASA)

Astronauts on the International Space Station are preparing for a possible emergency spacewalk tomorrow (May 11) to fix a serious leak of ammonia coolant on the orbiting laboratory.

On Thursday (May 9), the six residents of the station noticed frozen flakes of ammonia leaking from a coolant loop affixed to one of the eight solar arrays responsible for supplying power to the station. The crew is in no danger, NASA officials say, but if the leak continues, it could cause a shutdown in the loop, possibly preventing the array from generating power.

Space station commander Chris Hadfield of the Canadian Space Agency announced the possibility of the emergency spacewalk via Twitter (where he posts as @Cmdr_Hadfield) early on Friday. [How the Space Station's Cooling System Works (Infographic)]

"Good Morning, Earth! Big change in plans, spacewalk tomorrow, Chris Cassidy and Tom Marshburn are getting suits and airlock ready," Hadfield wrote. "Cool!"

NASA has not yet made an official decision on whether to conduct the spacewalk, and is still investigating the problem.

"The crew is not in danger, and the station continues to operate normally otherwise," agency officials wrote today in a statement. "Work is underway to reroute power channels to maintain full operation of the systems normally controlled by the solar array that is cooled by the suspect loop."

If the spacewalk goes forward, Cassidy and Marshburn — both NASA astronauts — will float outside the station to inspect the leak and possibly attempt to fix it.

"Suddenly very busy! Ammonia leak on the outside of station means that Cassidy and I will be doing a spacewalk tomorrow to try and repair it," Marshburn posted on Twitter (@AstroMarshburn) Friday.

This is not the first time space station crewmembers have spacewalked to repair a coolant leak. Last year, NASA's Sunita Williams and Japanese spaceflyer Akihiko Hoshidu took a spacewalk to troubleshoot a leak in a coolant loop on the station's Port 6 truss (its scaffolding-like backbone). The 2012 coolant leak was in the same loop as the current leak, but engineers don't yet know if the two leaks are related.

On the ground, astronauts Terry Virts of NASA and Samantha Cristoforetti of the European Space Agency are practicing the routine for tomorrow's potential spacewalk in the Johnson Space Center's Neutral Buoyancy Lab in Houston. This lab is a giant swimming pool that holds a full-scale mock-up of the International Space Station used for astronaut training.

"@AstroSamantha and I are doing a dry run in the NBL for tomorrow's planned Spacewalk, looking for the ammonia leak," Virts wrote on Twitter (@AstroTerry).

Hadfield, Marshburn and Cassidy are part of the station's Expedition 35 crew, along with Russian cosmonauts Roman Romanenko, Pavel Vinogradov and Alexander Misurkin.

Romanenko, Marshburn and Hadfield are scheduled to leave the space station on Monday (May 13) to return to Earth after close to five months aboard the $100 billion orbiting outpost. On May 28, three new crewmembers are expected to launch from Kazakhstan to join Vinogradov, Misurkin and Cassidy on the station.

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Miriam Kramer
Staff Writer

Miriam Kramer joined as a Staff Writer in December 2012. Since then, she has floated in weightlessness on a zero-gravity flight, felt the pull of 4-Gs in a trainer aircraft and watched rockets soar into space from Florida and Virginia. She also served as's lead space entertainment reporter, and enjoys all aspects of space news, astronomy and commercial spaceflight.  Miriam has also presented space stories during live interviews with Fox News and other TV and radio outlets. She originally hails from Knoxville, Tennessee where she and her family would take trips to dark spots on the outskirts of town to watch meteor showers every year. She loves to travel and one day hopes to see the northern lights in person. Miriam is currently a space reporter with Axios, writing the Axios Space newsletter. You can follow Miriam on Twitter.