January 31st marks the 51st anniversary of the launch of Explorer 1, America's first satellite. The flight, on 31 Jan 1958, came almost 4 months after the Soviet launch of the world's first satellite, Sputnik 1, and followed a failed U.S. attempt to launch a different satellite called Vanguard.

JPL's Explorer 1 was launched by a U.S. Army Redstone booster (AKA Juno I) from Cape Canaveral's Pad 26, and was America's entry into the space race. It first detected the Van Allen radiation belts that surround the Earth. The spacecraft orbited our planet until it burned up in the atmosphere in 1970.

The Soviets may have been first, but with Explorer's success, the Space Race was on! What will the next 50 years bring?