Explorer One and the Eighty-Four Days

On October fourth, nineteen fifty-seven, the Soviet Union placed a satellite called Sputnik into orbit around the earth. The United States did not have a satellite in orbit. This fact, which arrived on every radio frequency Sputnik broadcast as it passed overhead, concentrated a great deal of official attention in a short period of time.

The Army Ballistic Missile Agency at Redstone Arsenal had been proposing a satellite launch for years. The Eisenhower administration had chosen to route the first American satellite attempt through the Navy's Vanguard program, partly to keep the Army rocket team at arm's length for political reasons. Vanguard launched in December and exploded on the pad in front of the cameras. The administration turned to the Army.

The team at Redstone was given the assignment. Working with the Jet Propulsion Laboratory in California, they had eighty-four days from the decision to launch. They modified a Jupiter-C missile into a launch vehicle called Juno One. The Jet Propulsion Laboratory built the satellite. On the night of January thirty-first, nineteen fifty-eight, at ten forty-seven Eastern time, Explorer One cleared the pad at Cape Canaveral.

The satellite's instruments detected something unexpected. At high altitudes, the cosmic ray counters went silent. James Van Allen, the physicist who had designed the detector at the University of Iowa, concluded that the instruments were not failing. They were being overwhelmed. Intense radiation from charged particles trapped in Earth's magnetic field was saturating the detector. Explorer One had discovered what became known as the Van Allen radiation belts, one of the first major scientific findings of the space age.

Huntsville ran those eighty-four days.