Explorer 1 - Satellite.
A replica of Explorer 1, the first U.S. artificial satellite, is held aloft by launch-team members (left to right) William Pickering, James Van Allen, and Wernher von Braun. Using data on the space environment provided by the satellite, Van Allen determined in 1958 that belts of electrically charged particles surround the Earth. The belts were subsequently named in honor of the scientist.
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