A Soviet probe called Luna 3 took the first photographs of the far side of the Moon on October 7, 1959, while passing about 65,000 kilometres beyond it. No one had seen it. The Moon keeps the same face toward Earth because the time it takes to turn once and the time it takes to go round the Earth are the same, the result of tidal locking over billions of years, and that left a large part of the surface permanently out of view from anywhere on this planet.
The method was roundabout. There was no way to send a picture electronically at that distance and power, so the probe carried film. It photographed the Moon, developed the film on board, then scanned the negatives and transmitted them as radio signals once it was closer to Earth. The first attempt failed. The signal was too weak. The images that went round the world came from a second transmission on October 18, and they were grainy and hard to read on first sight.
They covered about 70 per cent of the hidden side. Two features stood out: a dark plain and a large crater with a bright central peak. The Soviet Academy of Sciences named them Mare Moscoviense, the Sea of Moscow, and Tsiolkovskiy, after the rocket theorist Konstantin Tsiolkovsky. Naming went to whoever got there first, which is why a Soviet name still sits on the maps of the far side today. The full set was published as an atlas in 1960.
The flight was part of a run of Soviet firsts in 1959. Luna 1 missed the Moon in January, Luna 2 hit it in September, and Luna 3 photographed around it three weeks after that, all from Sergei Korolev's design bureau. Faint as the pictures were, they settled what lay on the other side: more craters and far fewer dark plains than the near side, a difference in the crust itself and not an accident of bad photography.