NASA Investigating Another "Water in the Helmet" Incident At End of ISS Spacewalk

NASA astronauts Butch Wilmore and Terry Virts performed a successful 6 hour 43 minute spacewalk from the International Space Station (ISS) today, but after they were back inside the airlock, during repressurization, Virts noticed water inside his helmet.  It was a small amount compared to a major incident in July 2013, but NASA is now investigating what went wrong and whether another spacewalk planned for Sunday can go forward.

What little is known at this moment is that Virts noticed the water while he was face down in the airlock during repressurization.  In zero gravity, being face up or down should not matter.  He immediately reported it and ISS crewmate Samantha Cristoforetti (from the European Space Agency — ESA) began to help him remove the helmet.  That requires a number of steps and the process was not rushed since there was no emergency.  At one point ground controllers asked Russian cosmonaut Anton Shkaplerov, who was assisting Cristoforetti, to point a camera directly at Virts’ helmet so they could see what he was experiencing.  The blob of water was clearly visible adhering to the interior of his visor.

No problems were reported during the spacewalk itself.  It occurred only once Virts and Wilmore were back inside the airlock and it was repressurized to 5 pounds per square inch (psi).  Repressurization pauses at that point for a suit check before continuing to full repressurization to 14.7 psi.

At the request of ground controllers, once the helmet was removed, Cristoforetti touched the water to determine its temperature as part of troubleshooting steps.  She reported that it was cold.  She also reported that the Helmet Absorption Pad (HAP) at the back of the helmet was damp, but not saturated.  Virts later added that the water was not from his drink bag, which was fine, and that the water had a chemical taste.

NASA’s TV commentator reported that this suit, 3005, had a similar problem after a December 2013 spacewalk and that it occurred at exactly the same point — when repressurization reached 5 psi.

The December 2013 spacewalk was necessitated by the failure of a key ISS component (a coolant loop) and performed on a contingency basis because of an earlier and much more serious event in July 2013.  At that time, ESA astronaut Luca Parmitano’s helmet filled with water while he was outside the ISS performing the spacewalk. The cause ultimately was determined to be a clogged filter that allowed water from the suit’s cooling system to enter the helmet.  Parmitano later wrote a compelling account of the experience.  NASA has been even more careful about ensuring the spacesuits are functioning properly since then and implemented a number of changes — including installing HAPs to soak up any water that does enter a helmet.  That apparently was at least partially successful today.

NASA will now investigate this incident.  NASA said this afternoon that a decision on whether to proceed with Sunday’s spacewalk will be made at an already scheduled management meeting on Friday.  

Today’s spacewalk is the second of a trio that Wilmore and Virts are performing to ready ISS docking ports to be able to accommodate U.S. commercial crew spacecraft.  The first was successfully conducted on February 21.  NASA hopes to complete all three before March 12 when Wilmore will return to Earth as part of a routine crew rotation.  Two of the three spacewalks were delayed by a day as NASA worked an earlier issue with the suits’ fan pump separators.