Last month, a planned spacewalk was cut short by NASA because of a frightening accident in which an astronaut's helmet began filling with water. Now, astronaut Luca Parmitano of the European Space Agency has told his tale in full — of how he first began feeling water on the back of his neck, how he felt the water increasing and made the decision to terminate the mission, and how he eventually had to separate from his partner who secured the Space Station so they could re-enter. From there, it was a harrowing few minutes as Parmitano lost contact with the other astronauts, lost most of his vision because of the water buildup, and eventually reached the point where he wasn't sure if his next breath would be air or water. It's a must-read account of just how quickly things can go badly in space — a reminder of how "space is a harsh and inhospitable frontier" — hardly a frontier that we have mastered yet.