Slice of History - Anniversary of the Explorer Launch

Explorer 1 became the first successfully launched satellite by the United States when it was sent to space on 31 January 1958. A quick response to the Soviet Union’s launch of Sputnik 1, Explorer 1’s success marked the beginning of the US Space Age.

The satellite, which was designed, built, and operated by JPL, carried a cosmic ray detector (the satellite’s primary science instrument), which directly led to Principal Investigator Dr. James Van Allen’s discovery of radiation belts around Earth held in place by the planet’s magnetic field.

The success of Explorer 1 and other satellites that soon followed in 1958 led Congress to pass the National Aeronautics and Space Act that summer, which was signed into law by President Dwight D. Eisenhower, and NASA officially opened its doors in October 1958.

After more than 58,000 Earth orbits, Explorer 1 re-entered Earth’s atmosphere and was destroyed. The satellite made its final transmission to Earth on 23 May 1958.

Bonus: On the fifth anniversary of Explorer 1’s launch, JPL had a party and cut an anniversary cake! CL#23-6584

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