WIKIPEDIA: The United States was the dominant world power in the early 1950s. Lockheed U-2 spy plane flights over the Soviet Union provided intelligence that the US held the advantage in nuclear capability. However, an education gap was identified when studies conducted between 1955 and 1961 reported that the Soviet Union was training two to three times as many scientists per year than the United States. The launch and orbit of Sputnik 1 suggested that the USSR had made a substantial leap forward in technology, which was interpreted as a serious threat to US national security. This spurred the United States to make substantial federal investments in research and development, education and national security. The Juno I rocket that carried the first US satellite Explorer 1 had been ready to launch in 1956, but that fact was classified and unknown to the public. The Army’s PGM-19 Jupiter from which Juno was derived had been mothballed on the orders of defense secretary Charles Erwin Wilson amid interservice rivalry with the US Air Force’s PGM-17 Thor.