NASA’s 10 Greatest Achievements of All Time

10. Explorer 1

Explorer 1 was the first ever US satellite and was launched on January 31, 1958 roughly a year after the Soviet Union’s Sputnik 1 and 2 launched, which as a result was the beginning of the Cold War Space Race between the two nations. Explorer 1 was the first spacecraft to discover the Van Allen radiation belt, by returning data it collected over the course of four months. The discovery of the radiation belts is credited to NASA scientist James Van Allen due to his findings by using his Geiger-Muller tube on satellites, Explorer 1, Explorer 3, and Pioneer 3. Explorer 1 remained in orbit until 1970 and has since been followed by over 90 scientific spacecraft in the Explorer series.
10. Explorer 1