Before the United States got going in earnest with their Apollo program, the Soviet Union launched a series of missions to the moon. The Luna craft achieved a number of firsts, including the first lunar impact (Luna 2) and the first soft landing (Luna 9, depicted in a typically soft-color Soviet propaganda poster of the time). In between there was the Luna 3, a probe sent one-way to explore the side of the moon never before seen.

On this day, October 7, in 1959, the Luna 3 probe began transmitting the first of an eventual 17 photographs of the moon’s dark side, facing away from earth.

The moon takes 29.5 days to make a full rotation, and just about the same amount of time to go around the earth, meaning that no matter where on earth we are, we always see the same side of the moon. The first pictures from Luna 3 were low resolution, but clear enough to identify, among other features, mountain ranges considerably different than on the side facing the earth, and two seas the Russians named Mare Moscovrae (Sea of Moscow) and Mare Desiderii (Sea of Dreams).