NASA is not one for drama, particularly when it involves an astronaut and especially not when that astronaut is working outside the relative safety of their spaceship, in this case the International Space Station.

But on July 16, a NASA-trained Italian astronaut named Luca Parmitano faced more than a few dire moments when his spacesuit helmet started filling with water.

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Parmitano, who was making his second spacewalk, is thinking about the task at hand, namely unfurling a cable, when he feels that something is wrong, the astronaut writes in a blog post published this week on the European Space Agency’s website.

“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,” Parmitano wrote, referring to extravehicular activity — a spacewalk in NASA parlance.

Parmitano’s partner, NASA astronaut Chris Cassidy, comes over to see if he can figure out the cause of the leak.

“At first, we’re both convinced that it must be drinking water from my flask that has leaked out through the straw, or else it’s sweat. But I think the liquid is too cold to be sweat, and more importantly, I can feel it increasing. I can’t see any liquid coming out of the drinking water valve either,” Parmitano wrote.

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NASA decides to call off the spacewalk, which had been under way for only about an hour, and tells Parmitano to go back to the airlock.

But the astronaut’s troubles are just beginning.

“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,” he wrote.

He turns upside-down to get past an antenna and catches sight of a sunset. Then, “my ability to see — already compromised by the water — completely vanishes, making my eyes useless; but worse than that, 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,” Parmitano wrote.

“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. To make matters worse, I realize that I can’t even understand which direction I should head in to get back to the airlock. I can’t see more than a few centimeters in front of me, not even enough to make out the handles we use to move around the Station,” he wrote.

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The cause of the leak remains under investigation. Parmitano’s full story appears on his ESA blog.

Image: European Space Agency astronaut Luca Parmitano, Expedition 36 flight engineer, attired in his Extravehicular Mobility Unit (EMU) spacesuit, prepares to exit the International Space Station’s Quest airlock to begin a session of extravehicular activity (EVA) on July 9 along with NASA astronaut Chris Cassidy (out of frame). Credit: NASA