One of the astronaut's participating in NASA's planned six-hour spacewalk on Tuesday had to make an emergency return to the ISS's airlock after water began filling his helmet. Italian astronaut Luca Parmitano and Chris Cassidy were almost an hour into their spacewalk when Parmitano alerted ground control his head began feeling wet. At first he thought it was sweat. But ground control assured him that wasn't the case.

According to a report from the Associated Press, up to a half-liter of water had leaked into Parmitano's helmet, possibly out of his suit's drink bag. An exact cause has yet to be determined; things were apparently so bad that Parmitano couldn't even speak, and had to be helped back into the ISS by Cassidy. Imagine if the fellow was out there all alone. As if space wasn't incredibly dangerous enough, astronauts have to be weary of drowning in their own suits.

"He looks miserable," Cassidy relayed back to ground control. "But OK."

Cutting spacewalks short isn't really NASA's style, but the severity of the situation meant action needed to be taken, particularly since Partimano could hardly function. Both Cassidy and Partimano performed a separate spacewalk just last week, which went out without a hitch. No word on when the two will be given clearance to perform another spacewalk, or the Partimano's current suit can be fixed for future missions.