Update 5:00 p.m.: NASA officials said they had yet to ascertain the source of a water buildup inside Italian astronaut Luca Parmitano’s helmet during a spacewalk outside the international space station Tuesday.

In this image from video made available by NASA, astronauts discuss the aborted spacewalk aboard the International Space Station on Tuesday, July 16, 2013. A dangerous water leak in the helmet of Luca Parmitano, bottom center facing camera in white suit, drenched his eyes, nose and mouth, preventing him from hearing or speaking as what should have been a routine spacewalk came to an abrupt end. (AP Photo/NASA)

Mission Control aborted the spacewalk shortly after Parmitano reported a buildup of water in the back of his helmet. The accumulation continued to a point where the water began to collect around the astronaut’s face. The abort call happened so soon after the astronauts started the spacewalk that the walk became the second shortest in history at one hour and 32 minutes. Three officials participated in a press conference late Tuesday afternoon to discuss what happened and what the next steps would be in determining the leak.

“As far as where we go from here, clearly we have a problem at this point that we don’t understand,” said Kenneth Todd, the international space station’s manager for operations and integration.

The first two tasks of the spacewalk were completed before Parmitano reported that the CO2 sensor on his suit was not working properly. He then reported the sensation of water on the back of his head, which the lead spacewalk flight director, David Korth, described as a “gush” or “bubble” of water.

The CO2 sensor’s problems, Korth said, were attributed to the water buildup, since water tends to make the sensors malfunction. It was determined that Parmitano should continue with his tasks. But Parmitano’s partner on the walk, American astronaut Christopher Cassidy, reported that the water was coming around Parmitano’s ears and side of his face. It was then decided that the walk should be terminated.

“It wasn’t prudent to try to continue tasks,” given Parmitano’s discomfort, Korth said. “It was clear that he was having trouble.”

The astronauts then proceeded to the airlock, with Parmitano entering first. Roughly 20 minutes passed between the time the call was made to terminate the spacewalk and the time Cassidy entered the airlock. It was then reported that more water was accumulating in Parmitano’s helmet. In all, between one and 1.5 liters of water had accumulated in the suit, mostly in the helmet.

“It’s a good day today. The crew is inside and safe,” said Karina Eversley, lead spacewalk officer.

In attempting to determine the source of the leak, one of the first things the team thought about was the drink bag inside the spacesuit, which holds 32 ounces. Parmitano also reported that the water tasted odd, all but certainly ruling out the drink bag, which is needed to keep the astronauts hydrated during the multi-hour spacewalks. Another source of moisture, Korth noted, is sweat, but the volume of water was too large for that to be the source. The cooling and ventilation system in the suit holds about a gallon of water.

“We have not seen a problem like this before,” Eversley said, though she added that they do worry about the anti-fog. “We’ve seen a small amount of water get in that, and then get in the crew’s eyes. And that can be very painful.”

Enough water was in Parmitano’s communications cap that it blocked his ability to hear. If there’s enough water, it is possible for an astronaut to drown. “He certainly had that risk,” said Eversley.

“Luca’s doing great. He’s smiling and happy,” she said. Earlier, Parmitano had taken to Twitter to let the world know he was doing okay:

Korth described the astronaut’s performance as “grace under pressure,” calling on reporters to imagine walking around with a fishbowl on their heads as an experience comparable to what Parmitano went through. While Parmitano was clearly in discomfort, Korth and his team on the ground determined that the mission did not need to go into full emergency procedures. Still, the astronauts’ re-entry to the space station was sped up slightly.

In terms of next steps, the crew is discussing the day’s events in detail with team members on the ground as well as taking photographs and video of the suit. “Nothing is jumping out right now,” Korth said, referring to the possible source of the water.

As for whether this means the end of extravehicular activities, it doesn’t. But they are being put on hold until the source of the leak can be determined.

“We have to do EVAs,” said Todd, “EVAs are part of this business.”

Original Post: NASA aborted a space walk on Tuesday when Italian astronaut Luca Parmitano noticed a build-up of water in his helmet. Parmitano reported the situation back to Mission Control during the space walk. The space walk was aborted shortly thereafter as the water began to collect around the Italian astronauts mouth, nose and eyes. Upon re-entering the space station, Parmitano’s helmet was immediately removed, and the water wiped away. In a video feed, Parmitano appeared to be okay. Parmitano was the first Italian astronaut to conduct a space walk when he did so for the first time a week ago.

NASA has posted a timeline for Tuesday’s space walk, and it shows there was plenty to do on what was scheduled to be a six-hour session. The work that needed to be conducted was in preparation for the Russian Multipurpose Laboratory Module arrival later in the year, among other tasks. NASA plans to hold a news conference at 4:30 p.m. Eastern time on NASA TV, according to a release.