NASA astronaut Terry Virts Flight Engineer of Expedition 42 is seen working to complete a cable routing task while near the forward facing port of the Harmony module on the International Space Station, in this handout photo taken February 21, 2015, provided by NASA. Virts and fellow astronaut Barry "Butch" Wilmore completed a 6-hour, 41-minute spacewalk routing more than 300 feet of cable as part of a reconfiguration of the station to enable US commercial crew vehicles under development to dock to the space station in the coming years.[Photo/Agencies]

Wednesday's spacewalk began at 6:51 am EDT (GMT1151) and ended at 1:34 pm (1834 GMT) with the repressurization of the station's Quest airlock, and it was at that time that Virts noticed the water problem.

The water was "about three inches (seven centimeters) in diameter" and "it's kind of pooling on the front side of the helmet above his eye level" said European Space Agency astronaut Samantha Cristoforetti who helped remove Virts' helmet.

Cristoforetti also told flight controllers in Houston that the helmet absorption pad was damp, but not saturated, indicating that the water may not appear until very late in the spacewalk.

NASA said ground teams are currently analyzing the situation to confirm the source of the water.

The spacewalk was the third for Wilmore and the second for Virts. The duo was originally scheduled to perform a third spacewalk on Sunday. But given the water problem, NASA said will meet on Friday to review the issue.

In 2013, NASA aborted a planned six-hour spacewalk after Luca Parmitano of the European Space Agency reported a buildup of water inside his helmet.