I remember the early 1950s and this country was confident and of the mind to defend itself.The leaders were no nonsense types.If a space craft had crashed or exploded then crashed, that would indicate the flying saucer could probably be defended against by our military weaponry of that time.A nationwide military mobilization would have been undertaken to defend the country.This could not have been concealed or covered up, and simple deduction from the Roswell newspaper headlines would have indicated why the mobilization or martial law was in effect.