What caused an astronaut's helmet to fill with water from an unknown source? Officials are working to understand a serious leak that aborted a spacewalk outside the International Space Station, NASA representatives said at a news conference.
The mysterious leak put roughly 1 to 1.5 liters of water into the suit of the European Space Agency's Luca Parmitano, whose helmet began to flood partway through the exercise. The water eventually got into his eyes and eventually prevented him from speaking.
"I think we can all breathe a sigh of relief. … Clearly we have a problem at this point that we don't quite understand," Kenny Todd, chair of the space station mission management team, said Tuesday.
Parmitano and another astronaut had started off ahead of schedule by 18 minutes, but Parmitano -- Italy's first spacewalker -- soon noticed that a carbon dioxide sensor seemed to have gone bad. A few minutes later, he started reporting a kind of "gush," or a "bubble in the back of his head," said David Korth, the NASA flight director.
Korth told both astronauts to come back to the space station, cutting the spacewalk off at 1 hour, 32 minutes -- making it the second shortest spacewalk in ISS history. (Here's more information on the aborted spacewalk.)
It turned out that the carbon dioxide sensor was an early indication that the suit had suffered water damage, probably caused by the same leak that was filling Parmitano's helmet.
"We have not seen a problem like this before," said Karina Eversley, the lead spacewalk officer. Though a carbon dioxide sensor occasional goes bad, she said, "our suits are very robust."
Though Parmitano drank up the remaining contents of his 32-ounce drink bag in case that was the cause of the leak, he later said that the water in his helmet did not taste like normal drinking water. The leaking water was found in other parts of his suit too.
Though the source remains unclear, it's possible that the water was leaking from the liquid cooling system used to keep the astronauts comfortable, Eversley said.
In zero gravity, water pools into big globs and doesn't float downward or get easily absorbed -- which meant that Parmitano risked drowning in his own suit.
"You can imagine, you're in a fishbowl. So go stick your head in a fishbowl and try to walk around – that's not anything you take lightly," Korth said. "And certainly [spacewalking] is dangerous already."