Discovering Earth's radiation belts

The year 2017 marks the 60th anniversary of the dawn of the space age. On 4 October 1957, our planets first artificial satellite, Sputnik 1 (Russian for "companion"), was launched into low-Earth orbit by the Soviet Union. Although little more than a radio beacon, it showed the world that intercontinental ballistic missiles (ICBMs), at the core of Cold War military arsenals, could also place satellites into space. A mere month later, on 3 November, Soviet scientists launched a much larger and more sophisticated spacecraft-Sputnik 2, the second satellite sent into orbit and the first with a live animal; a model with a doll stand-in is pictured in figure 1. The event was timed to coincide with the eve of the 40th anniversary of the Bolshevik Revolution; the Soviets loved to celebrate their holidays with "labor" achievements.