When NASA astronaut Chris Hadfield climbed out of the International Space Station for his first spacewalk in April 2001, it was the culmination of decades of training and preparation. A hard-headed, disciplined pilot, Hadfield had studied maths, physics, engineering and robotics. He had flown over 70 different types of aircraft. He had spent 50 full days practicing spacewalks in the pool. “I was completely technically prepared for what was going to happen,” he says. Yet in a sense, he wasn’t prepared at all.