January 31, 1958 – Explorer 1, first American satellite launches
Explorer 1 became America’s first satellite on January 31, 1958. Following the Soviet success with Sputnik and the embarrassing failure in December 1957 of the first American attempt to launch a satellite, the U.S. Army launched a scientific satellite using a rocket that had been developed to test guided missile components.
National Air and Space Museum Image Detail
Explorer 1 (backup)