NASA astronaut explains cause of helmet leak that aborted spacewalk

US Astronaut Chris Cassidy explains in a video how a faulty cooling system was to blame for the helmet leak that abruptly ended a spacewalk outside the International Space Station two weeks ago.

Two weeks after NASA aborted a spacewalk outside the International Space Station when up to 1.5 liters of “funny-tasting” water leaked into Italian astronaut Luca Parmitano’s helmet, Maj. Parmitano’s spacewalk partner has released a video explaining what caused the leak that morning.

The spacewalk on the morning of July 16 was aborted 92 minutes into what was supposed to be a more than six-hour mission, after water began accumulating in Parmitano’s helmet from a then-unknown source. By the time that Parmitano was helped back into the ISS, about 1 to 1.5 liters of water had formed globs in the helmet, such that he could not hear, speak, or see.

In the video, US astronaut Chris Cassidy, explains from on-board the ISS that the water originated in the suit's cooling system and leaked into the ventilation system. Holding Parmitano’s helmet, Cmdr. Cassidy shows its white plastic back where the water began to seep in as a giant bubble. The water then flowed to fill in the astronaut’s ears and then came around to the front of the helmet to leak into his eyes, nose, and mouth, Cassidy explains.

“If it had continued to leak much more, it would have been really serious,” he says, adding that NASA engineers are still investigating what went wrong with Parmitano’s cooling system.

NASA officials had almost immediately pinpointed the spacesuit’s cooling system as the origin of the water, ruling out the 32-ounce drinking-water bag. The cooling system holds about a gallon of water tinged with iodine to prevent bacteria buildup. The iodine could explain the “funny” water taste that Parmitano had reported, NASA officials said at a conference held just after the incident.

“We have not seen a problem like this before,” said Karina Eversley, a NASA spacewalk officer, at the time, adding that drowning or choking was a real possibility had the mission not been expediently terminated. “This was a very serious issue.”

The scheduled walk was the second of two that the astronaut pair had planned to make outside the space station. The two astronauts had spent six hours and seven minutes outside a week earlier to make repairs on the station and to prepare it for a Russian module to dock there and had planned to finish the remaining work the July 16th walk.

Parmitano was wearing the same suit on the aborted walk that he wore during the previous walk, which went as planned.