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Luca Parmitano wrote about his experience with water filling his helmet during EVA on the International Space Station. It's a harrowing account and he explains part of his thought process:

I force myself to stay calm and, patiently locating the handles by touch, I start to move, all the while thinking about how to eliminate the water if it were to reach my mouth. The only idea I can think of is to open the safety valve by my left ear: if I create controlled depressurisation, 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.

As I read the phrase "eliminate the water", I wondered why he didn't consider the snorkel technique called "blast clearing":

The snorkeler expels water from the snorkel either with a sharp exhalation on return to the surface (blast clearing) or by tilting the head back shortly before reaching the surface and exhaling until reaching or breaking the surface (displacement method) and facing forward again before inhaling the next breath.

Obviously the displacement method won't work except in snorkeling, but blowing out a puff of air to push the water away seems like it would work. I mean, the water will go off to some other part of the spacesuit rather than blocking the trachea and drowning the occupant.

Bonus question: what are the odds that Luca's plan would have worked if he'd needed to exercise it?

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    $\begingroup$ The video of July 16th, 2013 Luca Parmitano's return back inside the ISS and the moment his helmet was removed can be seen in this news article from The Sydney Morning Herald. Astronaut Chris Cassidy explains the reason for this incident in this 2-part YouTube video, saying the water (roughly 1 to 1.5 liters, or about 2 to 3 pints) came from the suit’s cooling system. $\endgroup$ – TildalWave Aug 21 '13 at 7:16
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    $\begingroup$ @TildalWave: Cassidy's videos were very informative. I hadn't fully grasped how limited the volume of the helmet actually is. I'd sort of assumed the water could get back to the body of the suit somehow, but that's unlikely. $\endgroup$ – Jon Ericson Aug 21 '13 at 16:34
  • $\begingroup$ Surface tension is a problem, where it would cling instead of flowing. $\endgroup$ – geoffc Dec 14 '15 at 20:51
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No the blast clearing technique would not work, it requires gravity and the closed environment filled with one substance (water) of the snorkel to work. Neither are present in Luca's situation.

Tidalwave's Video links in his comment, indicate that attempts to blow or shake the water away were counter productive, resulting in water entering Luca's ears and nose. While all the data is not in, it appears that water was from the drinking bag and arrived through the ventilation system. The video showing the Lucas re-entering the station, indicates they knew that his drinking water was empty and helmet was filling, so actually his best choice might have been to simply drink any water near his mouth (hindsight in tranquility). This is of course based on no knowledge my part of another source for the water that would potentially be toxic.

Edit News Update BBC News 21 August 2013 Last updated at 05:22 ET "Luca Parmitano, 36, expressed bewilderment about the source of the water, as it did not appear to have come from his drinking flask. " http://www.bbc.co.uk/news/science-environment-23777804

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  • $\begingroup$ I have added a quote from BBC news that would tend counter the idea that source of the water was the drinking flask, but also provides no other clue for a source. $\endgroup$ – James Jenkins Aug 21 '13 at 14:48
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    $\begingroup$ Even if it was water, I'd hesitate not knowing what the water had been through to get to you... $\endgroup$ – PearsonArtPhoto Aug 21 '13 at 14:51
  • $\begingroup$ @PearsonArtPhoto, where could it have been that every other drop of drinking water in the ISS has not been before? science1.nasa.gov/science-news/science-at-nasa/2000/ast02nov_1 $\endgroup$ – James Jenkins Aug 21 '13 at 21:56
  • $\begingroup$ "might have been to simply drink any water near his mouth" - He actually did according to reports. But it was not helping him much ... $\endgroup$ – s-m-e Aug 23 '13 at 22:19
  • $\begingroup$ Didn't he go on record stating that the defogging materials on his helmet made the water "taste funny" when he drank bits of it, so he didn't know whether or not it was safe to ingest? $\endgroup$ – Magic Octopus Urn Jul 5 '18 at 12:52

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