On July 16, 2013, astronaut Luca Parmitano stepped into his spacesuit and out of the International Space Station. It was his second spacewalk. His first, on July 9, was the first ever made by an Italian. About one hour into a planned six-and-one-half hour spacewalk, water began seeping into Parmitano’s helmet. It covered his ears and communication gear. Unable to hear to his spacewalk companion, NASA astronaut Chris Cassidy, the water soon began wrapping around Parmitano’s head and into his nose. Cassidy and Parmitano, with assistance from ground control, quickly made their way back to the space station and helped Parmitano out of the damaged spacesuit. Parmitano is fine, and NASA is investigating what went wrong.
Chris Cassidy, a NASA astronaut onboard the ISS, explains how water filled the helmet of Luca Parmitano's spacesuit during a spacewalk.
Because Parmitano was in a microgravity environment, water didn’t pool at the bottom of his helmet and work its way up as it would have here on Earth. Instead, it collected in a blob behind his head, emanating from an air vent located at the base of his skull, according to Cassidy, who spoke in a video beamed down from the space station yesterday. That vent blows air up from behind an astronaut’s head and over the front of their face. Surface tension held the blob together, and as it grew, it slowly creeped out from a plastic shroud behind Parmitano’s head, saturating his communications cap. Capillary action then wicked the water forward, first covering his ears and then getting into his eyes and nose. If Parmitano and Cassidy had waited much longer, it’s possible the water would have covered his nose and mouth. He very well could have drowned in space.
No one currently knows where the water came from. Early suspicions focused on the suit’s cooling system, which contains four liters of iodine-laced water which flows throughout specialized long underwear worn by astronauts on spacewalks to cool their bodies from the heat of the unshielded sun. Currently, NASA is looking into problems with the suit’s life-support system, which, in addition to regulating oxygen and carbon dioxide levels, condenses and collects water vapor expelled by breathing. On July 27, they sent up a spacesuit repair kit aboard an unmanned supply craft that contained tools and spare parts to repair the life-support system.