Explorer I Satellite

Explorer 1, the United States’ first successful artificial satellite, reached orbit on January 31, 1958. With recent Vanguard rocket launch failures in mind, the Jet Propulsion Laboratory–Army Ballistic Missile Agency group adapted a Jupiter–C missile to send Explorer 1 into space.

The satellite transmitted for 105 days and gathered data on micrometeorites and cosmic radiation. Explorer data led space scientist James Van Allen to discover intense radiation surrounding the Earth, later named the Van Allen radiation belts. This flight backup was tested at Van Allen’s Iowa laboratory.

Transferred from NASA, Jet Propulsion Laboratory