A six-hour long spacewalk outside the International Space Station, or ISS, was aborted by NASA on Tuesday, after one of the Expedition 36 astronauts reported a water leak inside his helmet.

After a little more than 100 minutes into Tuesday’s spacewalk with U.S. astronaut Chris Cassidy, astronaut Luca Parmitano, of the European Space Agency, reported water floating behind his head inside his helmet. And although the leakage did not cause any harm to Parmitano, it was enough for Mission Control to end the spacewalk early.

“My head is really wet and I have a feeling it’s increasing,” Parmitano reported to ground control teams at the Johnson Space Center in Houston.

After the leakage harmed his communications system and the water was getting into his eyes, Parmitano quickly drank the remaining water in his drinking-water bag -- a potential source of the leak, USA Today reported.

After Parmitano reported the anomaly on Tuesday, flight director David Korth directed both astronauts to return to the station’s airlock. The spacewalk began at 7:57 a.m. EDT and ended at 9:39 a.m. EDT, when the airlock was re-pressurized. The cause of the leak is yet to be disclosed.

“He can’t hear. He looks miserable, but OK,” Cassidy, who took care of clean-up procedures before returning to the airlock, told flight controllers.

Tuesday’s spacewalk was the second of two July excursions to prepare the ISS for a new Russian Multipurpose Laboratory Module later this year. Both Cassidy and Parmitano wrapped up the first spacewalk, which lasted for six hours and seven minutes, on July 9.

Cassidy and Parmitano also had planned to accomplish tasks such as replacing a video camera, relocating television camera equipment, troubleshooting a faulty door cover over electronic relay boxes on the station’s truss, and reconfiguring the thermal insulation over a failed electronics box.

However, according to NASA, none of the tasks were urgent and the mission's managers will determine when they can be completed.

Tuesday’s spacewalk was the 171st spacewalk in support of station assembly and maintenance. It was also the second shortest in ISS history after the June 24, 2004 spacewalk by Russian cosmonaut Gennady Padalka and U.S. astronaut Mike Fincke, which lasted only 14 minutes. The spacewalk was suspended after the oxygen tank within Fincke's suite encountered a pressure problem.