A little more than 50 years ago, in 1952, the International Council of Scientific Unions (ICSU) took a step toward the satellite age. In recognition of a high point in solar activity between July 1, 1957 and December 31, 1958, the ISCU declared that period as the International Geophysical Year (IGY).

As part of the IGY, in October of 1954, the ICSU adopted a resolution calling for satellites to be launched for the purpose of mapping the surface of the Earth. One year later, the U.S. announced plans to launch an Earth-orbiting satellite. In 1955, the U.S. selected the Naval Research Laboratory (NRL) to build and launch the first satellite.

However, the U.S. was in for a shock  when the Soviet Union successfully launched Sputnik I, the world's first satellite, on October 4, 1957 . About the size of a basketball, weighing 183 pounds, and traveling in an elliptical orbit about the Earth, Sputnik made a complete trip around the planet in 98 minutes.

For the Soviets, Sputnik was an impressive technical achievement that caught the world's attention, but for the U.S. it was a stunning blow to fall behind in the race for space. Sputnik's size was greater and more impressive than NRL's intended 3.5-pound satellite payload. But, more importantly, the public quickly began to fear that if the Soviets had the technology to launch satellites, they might also be able to use it to launch nuclear missiles at the U.S. from the Soviet Union or Europe.

Immediately after the Sputnik I launch, the U.S. Department of Defense responded to growing political furor over the Soviet "first" in space, by approving funding for another U.S. satellite project. As plans for NRL's Vanguard satellite continued, Werner Von Braun and his Army Redstone Arsenal team began work on the Explorer satellite project.

In the meantime, the Soviets launched Sputnik II on November 3, 1957. Sputnik II carried a different and innovative payload-a dog named Laika.

On January 31, 1958, the U.S. successfully launched Explorer I. The satellite carried scientific instrumentation that eventually led to the discovery of the Earth's magnetic radiation belts, which were named after their principal investigator, James Van Allen. The Explorer program continued with Explorer IV launched successfully in July 1958. That was the last successful launch-the last two Explorer launches (Explorer V & VI) which carried lightweight, scientifically useful instrumentation, unfortunately failed.

In addition to launching the satellite age, Sputnik's orbit marked the beginning of the space race that consumed the minds and imaginations of people in the U.S. and the Soviet Union for the following decade.