The first USA satellite launch was on January 31, 1958, when the Explorer 1 satellite was launched into orbit by a Jupiter-C rocket. This launch marked the United States’ entry into the Space Race with the Soviet Union, which had launched the first satellite, Sputnik 1, in 1957. The Explorer 1 satellite was designed to study cosmic rays and was instrumental in the discovery of the Van Allen radiation belts around the Earth.
Explorer 1 was designed and built by the Jet Propulsion Laboratory (JPL) at the California Institute of Technology (Caltech), and its successful launch and operation paved the way for future US space exploration efforts.