From 1946, the National Advisory Committee for Aeronautics (NACA) had been experimenting with rocket planes such as the supersonic Bell X-1.[12] In the early 1950s, there was challenge to launch an artificial satellite for the International Geophysical Year (1957–58). An effort for this was the American Project Vanguard. After the Soviet launch of the world's first artificial satellite (Sputnik 1) on October 4, 1957, the attention of the United States turned toward its own fledgling space efforts. The US Congress, alarmed by the perceived threat to national security and technological leadership (known as the "Sputnik crisis"), urged immediate and swift action; President Dwight D. Eisenhower and his advisers counseled more deliberate measures.
