On October 4th 1957, the Soviet Union demonstrated that it had to be taken seriously. Only a few years prior they had lagged the US badly in both bombers and Nuclear weapons. Now, there was deep concern that the Soviet’s could launch a nuclear attack on the US with their new R-7 ICBM. To add fuel to the fire, Just 4 days after Sputnik launched the Soviet Union detonated a 20 megaton Hydrogen bomb.
“The success of the Russian Sputnik was convincing and dramatic proof to people around the world of the real prospects of space travel in the not too distant future. The fact that a 23-in. sphere weighing 184 lb has been placed in an almost precise circular orbit indicates that a number of important technological problems such as high thrust rocket engines, lightweight missile structures, accurate guidance, stable autopilot control, and large scale launching methods have been solved, at least to the degree required for a satellite project.” Astronautics, Nov 1957.