Day: March 31, 1966

The Soviet Union launches unmanned space probe Luna 10 toward the moon, where it becomes the moon’s first artificial satellite. Luna 10 remains functional for two months, during which a pre-recorded signal from it becomes one of the highlights of the 23rd Congress of the Soviet Communist Party. Luna 10 does not take photos of the moon from orbit, but does find varying concentrations of mass within the lunar surface. This is the last of the original “large” Luna probes, with later orbiters taking on a more compact form, and later large Luna probes containing landers and sample return rockets.