On March 18, 1965, a Soviet cosmonaut named Alexei Leonov opened the hatch of his Voskhod 2 spacecraft, gripped a thin tether, and floated out into nothing. He was the first human being to ever walk in space. Above him spun the Earth - blue, white, and stunningly beautiful. Below him, well, there was no below. He drifted, weightless, more than 300 miles above the planet, attached to his ship by a 17-foot cord that suddenly felt very thin.
The spacewalk was supposed to last about ten minutes. Then something terrifying happened: in the vacuum of space, Leonov's suit puffed up like a balloon. His gloves grew so stiff he couldn't bend his fingers, and his boots floated off his feet. He couldn't get back through the hatch. With his oxygen running low and his suit overheating, Leonov made a desperate, secret choice - he opened a valve to let air bleed out of his suit so it would shrink. It worked just enough. He squeezed back inside, exhausted and sweating buckets, having spent 12 minutes and 9 seconds in open space.
The trip home was almost as wild. The spacecraft landed in a snowy forest hundreds of miles off-target, and Leonov and his crewmate had to spend two nights in deep snow fending off wolves with a pistol until rescuers reached them on skis. Today, every astronaut who steps outside the International Space Station follows a path Leonov pioneered, including the basic suit design and tether systems. His twelve minutes of floating turned humans into a species that could walk among the stars.
