The successful attempt to put the satellite Sputnik into space confirmed the fear of the US citizens that the Soviet Union was capable of potentially placing weapons into space (like missile-technology satellites, etc).
Isolationism
because they are isolating themselves from the rest of the world. they wanted to focus on protecting themselves from the north so a takeover from the Mongols would never happen again. thus they stopped making ships and cut themselves off from everyone else.
It would change major events if it didn't fall into place with the original plan
