A spacewalk outside the International Space Station was cut short this morning when flight engineer Luca Parmitano noticed a water leak inside his helmet. “My head is really wet and I have a feeling it’s increasing,” the Italian astronaut told Johnson Space Center in Houston, about an hour into the mission. The leak got worse. Soon, both he and spacewalk partner Chris Cassidy were ordered back aboard the ISS.
According to dialogue between Parmitano, Cassidy and mission controll (dialogue that'll make your palms sweat), at least half a liter of water had leaked into Parmitano's helmet by the time he managed to get to the ISS airlock. That might not sound like a lot, but it's important to remember that water behaves very differently in microgravity, clinging to skin, hair, and – in Parmitano's case – the eyes, nose and mouth. As more and more water leaked into the helmet, it became increasingly difficult for Parmitano to see, speak and hear. The following tweets from Space Shuttle Almanac really drove this home for us:
Yes. All the panic.
Fortunately, Cassidy and Parmitano both managed to board the ISS quickly and safely, where they were received by Karen Nyberg, Pavel Vinogradov and Fyodor Yurchikhin, all of whom aided in an "expedited suit doffing" for Parmitano.
This was to be the second 6–7 hour spacewalk for Cassidy and Parmitano this month, during which the pair was scheduled to replace exterior cameras, reroute cables and perform other routine maintenance. At 1 hour, 32 minutes, today's spacewalk is the second-shortest in 171 spacewalks outside the ISS. The shortest: a 14-minute EVA conducted on June 24, 2004, when pressure problems in astronaut Mike Fincke’s spacesuit brought the mission to an almost immediate conclusion.