In a drafty log house on the muddy outskirts of a Russian provincial town, a deaf, self-taught math teacher the locals dismissed as the town crank, famous for sailing his bicycle down dirt roads under a giant umbrella, was mathematically mapping the mechanics of human spaceflight. Before the Wright brothers flew, Konstantin Tsiolkovsky calculated escape velocity and drafted blueprints for multi-stage rockets, space stations, and airlocks.

This episode follows a genius forged in a vacuum: the scarlet fever that took his hearing at nine, the Moscow library where philosopher Nikolai Fyodorov fed him the radical doctrine of Russian cosmism, and the living-room wind tunnel funded out of a schoolteacher's pocket. It ends with the superpowers' space race running on his equations, a crater on the far side of the moon bearing his name, and a pointed ...