On October 4, 1957, the Soviets launched the first satellite to reach earth orbit: Sputnik 1. The American government tried to downplay the event, but in actuality began aggressively pursuing their own satellite program.

The German-born American scientist Wernher von Braun had developed a Jupiter-C rocket for the Army and asked permission to launch a satellite with it. The government turned him down; however, having already decided on a Navy project, called Vanguard. On December 6, 1957, officials gathered the press to witness the first launch of the Vanguard rocket, which, after hovering a few feet off the ground, exploded into flames. After other disasters with Vanguard, von Braun was given the green light. On January 31, l958, a Jupiter-C lifted off. Two and a half minutes later, the first stage shut down and the next fired. Orbit was attained. The satellite itself orbited with the top stage of the rocket, ranging in distance from the earth between 218 miles (352 km) and 1,586 miles (2,554 km).

This satellite, called Explorer 1, was small in comparison to the Sputniks. It weighed only l0.5 pounds (4.7 kg). The Russians had larger rockets to launch their mammoth satellites, but the American representative had its advantages. Unlike Sputnik 1, Explorer 1 contained more than just instruments to measure the temperature and density of the upper atmosphere. It had a micrometer to measure debris in space and a radiation detector that found intense rings of radiation surrounding the earth at great altitude. Later, these rings were called the Van Allen radiation belts, named after the scientist who designed the experiment. Explorer 1 thus proved the great scientific value of satellites.