Conducting a spacewalk must be a pretty disconcerting experience as it is but when your helmet starts filling with water above your nose and ears then you'd be excused for really getting worried.
This is exactly what happened to astronaut, Luca Parmitano, who has written about his near-drowning on his blog.
The Italian flight engineer was installing parts on the outside of the International Space Station (ISS) accompanied by fellow astronaut, Chris Cassidy, when the incident happened.
He writes: "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.
"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."
The Nasa team overseeing the operation at Cape Canaveral confirmed it was not sweat and immediately ordered they abort the mission.
As they made their way back to the airlock, the water was obscuring his vision and covering his nose which he describes as "a really awful sensation".
He adds: "The water has also almost completely covered the front of my visor, sticking to it and obscuring my vision.
The space walk was being broadcast online (file photo)
"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 realise that I can’t even understand which direction I should head in to get back to the airlock."
While waiting for his colleague to reach him he remembered his safety cable's recoil mechanism with enough force to get him back to the hatch.
He writes: "It’s not much, but it’s the best idea I have: to follow the cable to the airlock."
By this point the situation was so dire he considered releasing the safety valve by his ear but "making a ‘hole’ in my spacesuit really would be a last resort".
He finally made it into the airlock with Cassidy where he had to wait for the pressure to normalise.
Parmitano writes: "At one point, Chris squeezes my glove with his and I give him the universal ‘ok’ sign with mine."
The source of the accident is still being investigated and all spacewalks have been suspended until the cause has been found.
Parmitano finishes his blog: "Space is a harsh, inhospitable frontier and we are explorers, not colonisers.
"The skills of our engineers and the technology surrounding us make things appear simple when they are not, and perhaps we forget this sometimes.
"Better not to forget."
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