Controlling a lander behind the moon is like flying a drone from behind a brick wall thousands of miles thick. This episode explains how the China National Space Administration’s Chang’e 4 mission solved that radio blackout to make the first-ever soft landing on the lunar far side on January 3, 2019, inside the Von Karman crater within the South Pole-Aitken Basin, an impact scar roughly 13 kilometers deep that likely exposed the moon’s mantle.

We cover tidal locking and why the far side is not the dark side, the Queqiao relay satellite parked in a halo orbit around the Earth-moon L2 point, the X-band and S-band communication chain, and the Yutu-2 rover, a repurposed Chang’e 3 backup redesigned to survive razor-sharp lunar dust that went on to break the Soviet Lunokhod 1 longevity record. The episode also explores the olivine and pyroxene mantle minerals detected on the surface, low-frequency radio astronomy in the quietest environment near Earth, the Longjiang microsatellites, the sealed biosphere in which cotton seeds sprouted for nine days, radiation readings two to three times those on the ISS, international payloads from Germany, Sweden, the Netherlands, and Saudi Arabia, and the data quietly shared with NASA despite a congressional ban.

• Why every earlier lunar landing stayed on the near side
• How a halo orbit at L2 keeps the Magpie Bridge in view of Earth and the far side
• Radioisotope heater units that survive minus 190 degree Celsius lunar nights
• What went wrong with the first Yutu rover and how Yutu-2 was fixed
• Why a far-side radio telescope could hear signals from the cosmic dark ages