Between 1961 and 1984 the Soviet Union sent 18 probes to Venus, and the planet crushed, cooked, and blinded them one after another. This episode traces the extreme trial and error of the Venera program, starting with engineers who as late as 1964 were still building buoyancy systems in case a probe splashed into a Venusian ocean. It covers the failed flybys of Venera 1 and 2, the first impact on another planet by Venera 3 in 1966, and the parachute probes Venera 4 through 6 that were crushed in the atmosphere while discovering it was overwhelmingly carbon dioxide.

The conversation explains how the American Mariner 5 used radio occultation to reveal surface pressures of 75 to 100 atmospheres, forcing the Soviets to retract the claim that Venera 4 reached the ground. That led to the brute-force titanium sphere of Venera 7, which crash-landed  ...