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| An Explorer 1 launch cover from "H. Flick", postmarked at Patrick Air Force Base with a machine cancel on January 31, 1958. |
The United States joined the Space Race with the launch of Explorer 1 on January 31, 1958, as part of its program for the International Geophysical Year and in reaction to the Soviet Union's launch of Sputnik 1.
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| Photo: Dr. William H. Pickering, Director of the Jet Propulsion Laboratory from 1954 to 1976. Under his guidance, Pickering's team launched Explorer I aboard a Jupiter-C rocket from Cape Canaveral on January 31, 1958. |
Explorer 1, recognized as the first U.S. satellite, is famous for its discovery of the Van Allen radiation belts, which are radiation zones surrounding Earth. The presence of these belts was confirmed through the Explorer 1 and Explorer 3 missions in early 1958, led by Dr. James Van Allen at the University of Iowa.
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| Photo: Professor Ernest Ray (left) and James Van Allen (right) analyze the orbit of Explorer 1. |
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| An Explorer 1 launch cover from "Goldcraft", postmarked at Patrick Air Force Base with a machine cancel on January 31, 1958. |
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| Photo: Dr. Wernher Von Braun addresses a news conference, explaining how the Jupiter-C missile successfully launched Explorer 1 into orbit. The Jupiter-C was developed by the U.S. Army Ballistic Missile Agency (ABMA) under von Braun's leadership. |
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| Photo: An image showing the Jupiter-C missile on the launch pad. |
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| An Explorer 1 launch cover from "Sarzin", postmarked at Port Canaveral with a hand cancel on January 31, 1958. |
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| Photo: An illustration showing the various stages of the flight of Explorer 1. |
(Reference from
Explorer 1)
