NASA cut short a spacewalk outside the International Space Station Tuesday after water began building up inside the helmet of an Italian astronaut.
Luca Parmitano was conducting his second career spacewalk when he reported feeling water on the back of his head. As large quantities of liquid collected inside his helmet, NASA called off the spacewalk, and Parmitano, along with fellow astronaut American Christopher Cassidy, made it back into the orbiting outpost after one hour and 32 minutes outside the research lab. Last week, Parmitano became the first Italian to walk in space.
During a news conference
to discuss the unexpected events, the U.S. space agency said it initially suspected that Parmitano's drinking water supply might have escaped into his helmet. NASA, however, said an investigation has ruled out that possibility.
"It was definitely a leak in the system," said Karina Eversley, the lead spacewalk officer. "This was not a normal amount of water," she added.
The ISS crew found that between 1 and 1.5 liters of water had flooded throughout Parmitano's suit, although it was concentrated mostly in his helmet.
The team is now investigating whether a leak in the suit's cooling system, which contains about four liters of water, could be responsible. Parmitano reported that the water had a "funny taste," which may help the investigators to pinpoint its source.
In zero gravity, water floats freely in large globs, rather than settling in contained spaces. Astronaut Chris Cassidy visually inspected Parmitano's helmet, and reported that the volume of water seemed to be increasing. It was at this point that NASA aborted the mission, and Parmitano returned quickly to the ship's airlock, followed by Cassidy.
As Parmitano returned to the station, the amount of water increased to the point that it congealed around his ears and face, making it difficult for him to hear, see, and speak.
"You can imagine you're in a fishbowl," said David Korth, a NASA flight director. "This is not a thing you take lightly. He did a great job of keeping calm and cool."
Karina Eversley confirmed that Parmitano may have been at risk of drowning had his suit not been removed quickly, and that this was one of the more serious incidents to occur in the history of spacewalking.
Eversley and Korth said that Parmitano has suffered no adverse effects of his suit malfunction, and that he, Cassidy, the rest of the ISS crew and NASA ground control had performed admirably and efficiently under pressure.
"Luca is doing great - he's smiling and happy," said Eversley.
Space Station Spacewalk Ended Early for Malfunction (NASA TV)