Astronaut Tom Jones had trained for years for one climactic moment: his first step through an airlock into the vast nothingness of space. What neither he nor anyone else had counted on was a door that refused to open. But that is the nature of spaceflight—anything can, and sometimes does, go wrong. Ultimately, Jones spent fifty-two days orbiting Earth, including more than nineteen hours outside during extravehicular activity—that is, sky walking.