In July 1975, American and Soviet spacecraft docked in orbit for the first time in history. This episode opens with the near-fatal splashdown in which toxic hydrazine fumes flooded the Apollo cabin, then rewinds to the diplomatic groundwork, from Kennedy and Khrushchev's letters around the Cuban Missile Crisis to the détente era that finally made a joint mission politically possible.

The conversation digs into the engineering problems: opposite design philosophies favoring automation versus manual control, incompatible cabin atmospheres of pure low-pressure oxygen versus a sea-level nitrogen-oxygen mix, and the Androgynous Peripheral Attach System that let neither nation play the passive partner. It profiles the crews, including Deke Slayton's 13-year wait for medical clearance and the misdiagnosis that spared Leonov and Kubasov from the fa ...