Nasa has aborted a spacewalk after a water leak was spotted inside an astronaut's helmet.
The spacewalk was taking place outside the International Space Station and was being broadcast online when the problem was noticed.
The space walk by ISS Flight Engineers Chris Cassidy and Luca Parmitano was the fifth performed on the space station in 2013, and the 171st in the space station's history.
Italy's first spacewalker, Parmitano, said that he felt water on the back of his head about an hour into the space walk.
At first he thought it was sweat, but was repeatedly told it was not by Nasa officials.
The Nasa feed indicated the water had gotten into Parmitano's eyes, at which point the men were ordered back into the station by the team at Cape Canaveral. According to the live feed of the mission the issue was so serious Parmitano needed help to get back into the space station, and up to half a litre of water may have escaped. Both astronauts were unhurt.
The engineers were outside the station installing bypass jumpers to provide power redundancy to components elsewhere on the station.
Other tasks scheduled included replacing a video camera, checking door covers and moving television equipment.