NASA/ESA Luca Parmitano in his space suit.

On July 16, NASA

cut short a spacewalkoutside of the International Space Station after Italian astronaut Luca Parmitano reported water inside of his space suit helmet.

He’s just written a blog post on the European Space Agency website describing what happened that day, including the feeling of being blind and drowning in the blackness of space.

The spacewalk started out just fine, but it was dark because the sun had set: “It is pitch black outside, not the colour black but rather a complete absence of light,” he wrote.

Parmitano and NASA astronaut Chris Cassidy set out from the airlock, taking two different routes to the section of the station they were set to be working on. Parmitano’s was more direct — a fact that might have saved his life.

“At that moment, none of us in orbit or on Earth could have imagined just how much this decision would influence the events of the day,” he wrote. Not long into their mission, Parmitano noticed something wrong:

I ‘feel’ that something is wrong. The unexpected sensation of water at the back of my neck surprises me — and I’m in a place where I’d rather not be surprised. I move my head from side to side, confirming my first impression, and with superhuman effort I force myself to inform Houston of what I can feel, knowing that it could signal the end of this EVA. On the ground, Shane confirms they have received my message and he asks me to await instructions.

NASA/ESA When his helmet started filling with water, Luca Parmitano was wedged between three pieces of the space station.

The engineers in Houston canceled the space walk and told the astronauts to make their way to the airlock, where they would reenter the space station. This was a good call, because Parmitano’s situation was getting more dire by the minute:

As I move back along my route towards the airlock, I become more and more certain that the water is increasing. I feel it covering the sponge on my earphones and I wonder whether I’ll lose audio contact. The water has also almost completely covered the front of my visor, sticking to it and obscuring my vision…. the water covers my nose — a really awful sensation that I make worse by my vain attempts to move the water by shaking my head. By now, the upper part of the helmet is full of water and I can’t even be sure that the next time I breathe I will fill my lungs with air and not liquid.

NASA/ESA NASA Astronaut Chris Cassidy was on the space walk with Luca Parmitano when his helmet started leaking water.

Parmitano was supposed to wait for Cassidy to help him over to the airlock, but realised it may take too long. He pulled on his safety cable, which pulled him toward the airlock and he followed it there, locating the handles on the outside of the space station by touch alone.

He hatched a plan of what to do if the water filled his helmet and covered his mouth:

The only idea I can think of is to open the safety valve by my left ear: if I create controlled depressurization, I should manage to let out some of the water, at least until it freezes through sublimation, which would stop the flow. But making a ‘hole’ in my spacesuit really would be a last resort.

He did make it to the airlock, and eventually Cassidy reached it as well. The two could make their way back inside the space station … after repressurizing themselves, that is:

Now that we are repressurizing, I know that if the water does overwhelm me I can always open the helmet. I’ll probably lose consciousness, but in any case that would be better than drowning inside the helmet.

NASA/ESA Luca Parmitano was working on the space station when the leak happened.

When they reach the safety of the space station, and Parmitano can finally remove his malfunctioning helmet, his nose and ears were still full of water, since there was no gravity to drain it away.

The leak in Parmitano’s suit seems to have been coolant water that leaked into his ventilation system through a connector between the helmet and space suit, according to a a video from Cassidy. The team still hasn’t finished that space walk.

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