Spacewalk Aborted When Water Fills Astronaut's Helmet 125
astroengine writes "A planned six-hour spacewalk outside the International Space Station came to a dramatic and abrupt end on Tuesday when water started building up inside the helmet of Italian astronaut Luca Parmitano. Parmitano and NASA astronaut Chris Cassidy were less than an hour into their spacewalk, their second in a week, when Parmitano reported that his head felt wet. 'My head is really wet and I have a feeling it's increasing,' Parmitano reported to ground control teams at the Johnson Space Center in Houston. Parmitano returned safely to the space station interior, but the cause of the leak was not immediately known."
Re:I guess those Space Nutters were right (Score:5, Informative)
I'm not a rocket surgeon; but I'd guess a failure somewhere in the PLLS [wikipedia.org]. That component is supposed to condense and remove water vapor from the gas(as well as scrubbing CO2 and adding oxygen if needed) before reintroducing the fresh atmosphere into the astronaut's helmet.
Between a possible failure in the mechanism for removing condensation(which would cause the output to be alarmingly damp if you aren't expecting it; but would be a self-limiting problem since there just isn't that much water vapor available), there is the more serious possibility that the LCVG [wikipedia.org], or the heat exchanger that keeps the coolant water in that chilled, is leaking, which might actually end up being enough water to impair breathing(especially with surface tension but not gravity), or impair the cooling functions enough to threaten the astronaut's ability to function. If he's on a tether, they'd presumably just reel him in if he were to pass out from thermal overload; but a free walk would not be a good time to lose consciousness...