This episode is all about the "Space Race" against the Soviet Union, to the moon! Following World War II, the U.S. was pitted against the Soviet Union in a period known as "The Cold War." The Soviet Union and the U.S. tried to out-perform one another; not just in the realms of political or military influence, but also in scientific achievement, and discovery.
The first part of the episode briefly outlines the Cold War, and how the "Space Race" got started, with the Soviets' launching of Sputnik, in October, 1957. Next came the U.S. competing with the Soviets to launch a man into space. The U.S. considered several methods for putting a man into space, but ultimately decided on Project Mercury, and set out to find seven astronauts to carry America's torch into space.
The second part of the "Space Race" episode outlines NASA's Project Gemini, and the Apollo Program. Project Gemini is the commonly forgotten bridge between Mercury and Apollo. Gemini served as the test-bed for the Apollo program, where astronauts and engineers would learn the skills and tasks needed to make a trip to the moon possible.
After the successes with the Gemini program, both the Americans and the Soviets felt the consequences of "Go Fever" with the losses of the Apollo 1 crew, and of cosmonaut Vladimir Komarov, in 1967. The year 1968 proved to be a pivotal year for the U.S., since the Apollo Program learned from its mistakes, and got back on track toward the moon. Apollo 8 would circle the moon in December of that year, and in July 1969, America won the Space Race with Apollo 11. The Apollo program ended after Apollo 17 - even though more flights were scheduled, budget cuts forced the program to end early. The Apollo-Soyuz Test Program in 1975 paved the way for international flights, which are still going on today!