The pilot of the first American orbital spaceflight had to lobby his bosses to bring a 35-millimeter camera he bought at a drugstore. This episode reconstructs John Glenn's Mercury-Atlas 6 mission on February 20, 1962, from the months of scrubs over fuel leaks, gyroscopes, and cloud cover, through the broken hatch bolt that added 42 minutes on the pad, to the moment Scott Carpenter said Godspeed, John Glenn and a radio glitch kept Glenn from hearing it.

In orbit, Glenn reported a dust storm over Kano, saw the lights of Perth switched on for him, and tested the mysterious fireflies by banging on the capsule wall. Then a yaw thruster failed, forcing hours of manual fly-by-wire control that burned nearly 30 percent of his fuel. Meanwhile a sensor called Segment 51 suggested the heat shield was loose, and mission control chose to keep the retro ...