On Jan. 31, 1958, the launch of the first United States satellite let a country shocked by the Soviet Union's 1957 jump into space finally breathe a little more easily.
But the Explorer satellite, launched atop a Jupiter C rocket developed under the direction of Wernher von Braun, had a scientific as well as symbolic role, carrying a cosmic ray detector designed to measure radiation levels in orbit.
Readings turned out to be very different than what were expected, and with the help of a second experiment launched two months later, scientists were able to deduce the presence of the charged-particle belts surrounding the earth now known as the Van Allen Belts, named after the director of the experiments.
The 30.8 pound Explorer 1 satellite looped around the earth about 12.5 times per day, transmitting only until May 23, 1958. It finally reentered the atmosphere and burned up on March 31, 1970.
NASA's Jet Propulsion Laboratory has an excellent site devoted to the Explorer launch, with pictures, multimedia, and history enough to satisfy any space buff.
JPL Explorer 1 site [JPL]
(Image: Jet Propulsion Laboratory Director William Pickering, scientist
James Van Allen and rocket pioneer Wernher von Braun hold up a model of
Explorer 1 after the rocket's successful launch. Credit: JPL)
