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| Explorer 1 launch cover with H.Flick cachet. |
The United States entered the Space Race by launching Explorer 1 on January 31, 1958, as part of the United States program for the International Geophysical Year and in response to the launch of the Soviet satellite Sputnik 1.
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| Photo: Dr. William H. Pickering, Director Jet Propulsion Laboratory (1954-1976). Pickering's team launched Explorer I on a Jupiter-C rocket from Cape Canaveral on 31 January 1958 less than four months after the Soviet Union had launched Sputnik. Under his leadership, JPL had many successes in space missions: Explorer, Pioneer, Mariner, Rangers 7-9, Surveyor, and Viking. |
Explorer 1 being the first US satellite, was known for discovering the Van Allen radiation belt. Van Allen belts refers specifically to the radiation belts surrounding Earth. The existence of the belt was confirmed by the Explorer 1 and Explorer 3 missions in early 1958, under Dr James Van Allen at the University of Iowa. Aboard Explorer 1 were a micrometeorite detector and a cosmic ray experiment designed by Van Allen and his graduate students, with the satellite deployment of the sensor package supervised by Ernst Stuhlinger, who also had an expert cosmic ray background. Data from Explorer 1 and Explorer 3 (launched March 26, 1958) were used by the Iowa group to make "the first space-age scientific discovery": "the existence of a doughnut-shaped region of charged particle radiation trapped by the Earth’s magnetic field".
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| Photo: Prof. Ernest Ray (left) and James Van Allen (right) study the Explorer 1 orbit. |
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| Explorer 1 launch cover with Goldcraft cachet |
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| Photo: Dr. Wernher Von Braun at news conference explaining how the Jupiter-C missile put Explorer 1 into orbit. Jupiter-C was designed by the U.S. Army Ballistic Missile Agency (ABMA), under the direction of Wernher von Braun. |
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| Photo: Jupiter-C missile at launch pad. |
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| Explorer 1 launch cover with Sarzin cachet |
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| Photo: Stages in Explorer 1 launch. |
(Reference from
Explorer 1)
