Once World War II ended, the United States and the Soviet Union became locked in a competition to move beyond earth. The US had more German scientists, but the Soviets achieved many firsts: the first satellite in orbit, the first man in space, the first woman in space, the first space walk, etc. The USSR planned to land men on the moon in 1967, but that didn't happen, and the Soviet space program went awry in many ways. The US got to the moon first in 1969.
So what happened? The Soviets relied heavily on one man, Sergei Korolev. Korolev was a brilliant rocket scientist who spent the war in Stalin's Gulag, but was freed when it became clear that the US was recruiting Germany's premiere rocket scientists. Korolev designed the best rockets, and quickly. But after his death in 1966, it became clear to his organization that they had relied too much on the one guy who knew what he was doing. Read about Sergei Korolev and what he did for the Soviet space program at Big Think.
(Image credit: Музей космонавтики/Главархив Москвы)