It is the policy of the United States that activities in space should be devoted to peaceful purposes for the benefit of all mankind.

—National Aeronautics and Space Agency Act of 1958

Once it became obvious that space exploration was an achievable reality, it became a national priority for rich and powerful countries. Following World War II there were only two superpowers in the world—the United States and the Soviet Union, and they considered each other enemies.

Both superpowers had military, scientific, and political reasons to go into space. Outer space was a potential battlefield and a great place to spy on enemies on the other side of the world. However, scientists valued space travel for another reason. They wanted to gather data from space to help them unravel the mysteries of the universe. From a political standpoint, a successful space program...