In response to the Soviet Union’s Sputnik satellite achievement, the United States launched Explorer 1. Carried by a Jupiter-C rocket on January 31, 1958, Explorer 1 provided groundbreaking evidence of the existence of the Van Allen radiation belt, which protects the Earth from harmful solar radiation. All three upper stages were housed within the barrel, which spun at a dizzying 750 revolutions per minute. The success of Explorer 1, led by the United States Army, resulted in the formation of the National Aeronautics and Space Administration (NASA), a civilian organization dedicated to the exploration of space.

Specifications:

•Height: 69.55 ft / 21.2 m

•Mass: 64,200 lb / 29,180 kg

•Maximum diameter: 5.84 in / 1.78 m

•Thrust at launch: 83,000 lb / 37,648 kg