It sounds like a cheap science fiction horror movie plot. But it wasn’t. In 2013, Italian air force colonel, seasoned test pilot, and astronaut Luca Parmitano nearly drowned in space during a spacewalk from the International Space Station (ISS). If not for his experience, cool demeanor, and training, he would have.
On July 16th, Parmitano suited up for the second space walk as part of an effort to install a new Russian multipurpose platform. An hour and a half into the mission, Parmitano felt water on the back of his neck, from an unknown source. He radioed Houston with his concern, initiating a scramble on the ground as they tried to evaluate the problem, and he continued to work. For a few minutes. He then radioed that his helmet was rapidly filling with water from an unknown source and mission control ordered the EVA canceled. Parmitano headed back to the airlock but a change in his orientation suddenly brought a large volume of water into the helmet, covering his eyes, nose, and part of his mouth, blinding him, and cutting all communications. His EVA partner, astronaut Chris Cassidy had gone to recover the EVA pack filled with equipment, and Parmitano was literally flying blind, retracing his steps to an airlock he could no longer see. He made it to the airlock and floated in, followed quickly by Cassidy, and they closed the hatch to begin the repressurization process, which took several minutes.
Still unable to communicate and waiting for the time he can remove his helmet, Parmitano remembers “taking it one second at a time. At that point I’m virtually isolated from a sensory point of view. I can’t hear. I can’t really see. I can’t move. Every time I moved, the water sloshed around.” The other astronauts, waiting anxiously on the other side of the airlock door, considered an emergency repressurization, which would have blown out his eardrums, but would have saved his life. He was, however, squeezing the hand of Cassidy, in a signal that he was alright.
When Parmitano’s helmet was finally removed, a liter and a half of water spilled out, more than enough to have drowned him. Reportedly, when the helmet came off, all the calm, collected astronaut said was “Thanks, guys.”
The fact that a disaster was avoided can be attributed to many different factors, including luck. But most important, for everything the astronauts do, is training and experience. Parmitano was a test pilot and astronaut, which alone is indicative of the degree of training and nerves these professionals bring to the job. But he also has experience as a scuba diver. Even that, however, isn’t all. When asked later how he was able to handle the frightening incident, he noted “What happens is that you get trained. And all the people who contributed to that should take the credit. I followed the route [back to the airlock] because I had studied the station—because somebody on the ground told me to study it.”
And do you think this in any way traumatized him? After the incident, and his return to Earth, Parmitano served as a member of the underwater NEEMO-20 crew for two weeks in July-August 2015. And in 2019, he returned to the ISS for a second tour and completed two different six-hour spacewalks. The right stuff.
The leak was thought to have been caused by a failure in the suit cooling system, which uses water. A snorkel-like attachment has been added to the helmets to permit the astronauts to breath if a similar problem reoccurs and other new safety protocols put in place.
 NEEMO (the NASA Extreme Environment Mission Operations) is the project that has test subjects live in the NASA underwater laboratory Aquarius to test challenges associated with future space missions.