"A spacesuit is like a small, individual spacecraft but it can malfunction, as Italian astronaut Luca Parmitano discovered when his helmet started to fill with water during a spacewalk in 2013.
His ventilation system had sprung a leak. Liquid doesn't flow under zero gravity, so the water sat in his helmet covering his eyes and ears, and blocking his nostrils.
At risk of drowning, he had to cut short his spacewalk.
"I started going back to the airlock and the water kept trickling," says Parmitano. "It completely covered my eyes and my nose. It was really hard to see. I couldn't hear anything. It was really hard to communicate."
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