Faulty helmet forces ISS astronauts to abort spacewalk ISS astronaut Karen Nyberg (R) assists Luca Parmitano after bringing him back into the station following the aborted space walk. Photograph: Ho/AFP/Getty Images Two astronauts have been ordered to abort a spacewalk on the International Space Station after water began to leak into one of the men's helmets. Nasa scrubbed their work plan a little more than an hour into what was due to be a six-and-a-half-hour spacewalk when Luca Parmitano felt water floating behind his head. The European Space Agency astronaut, who is on his first mission to the orbiting outpost, thought the water was sweat, but Nasa groundstaff assured him it was not. Parmitano completed his first spacewalk last week. Nasa cut a live feed of the spacewalk after an estimated 500ml of water leaked into Parmitano's helmet. "My head is really wet and I have a feeling it's increasing," Parmitano told flight controllers in Houston. "There is some in my eyes, and some in my nose," he added. It's a lot of water. Nasa said the water was not an immediate health hazard, but mission control decided to end the spacewalk early. Parmitano was helped back to the space station's airlock by Chris Cassidy, his partner on the spacewalk. Cassidy, a former Navy Seal, told Houston: "I don't want to make a mistake and make it worse." As the astronauts waited for the pressure to build up in the airlock - making entry to the space station possible - Cassidy noted that Parmitano looked fine. "He looks miserable, but OK," he said. Parmitano was helped out of his helmet and suit by fellow astronaut Karen Nyberg. Nasa was unclear why the suit sprang a leak, but said specialists would investigate the problem. "I doubt he was in any danger of drowning, but this could have caused problems for the mission, and there were good reasons to abort," said Kevin Fong, director of space medicine at University College London. There's a lot of fragile stuff on the outside of the space station and you don't want to be in a position where your vision is obscured as you are moving around, or be worrying where water is going to float to next. There's enough going on already. The astronauts had planned to do work to ready the space station for a new Russian multipurpose laboratory that is due to arrive later this year. Their other tasks were to replace a video camera on a Japanese experiment module, move wireless TV equipment, and fix a faulty door cover. The spacewalk began at 7:57 am, and ended 1 hour 32 minutes later when the airlock was repressurised.