Sixty-five Explorer satellites, all unmanned, were launched from Earth between 1958 and 1984, seven failed to launch successfully.
They were all sent into space to collect data and conduct experiments on specific phenomena.
The areas of study included radiation belts, magnetic fields, solar wind, electromagnetic rays, the ionosphere, and Halley’s comet.
In the aftermath of the Challenger disaster of 1986, the entire U.S. space program was modified, including the Explorer program.
Further research of this kind would be conducted by “Small Explorers,” smaller, less expensive satellites.
The news media called the Explorer’s unsuccessful test run (1957) “Flopnik” and “Kaputnik.”