Sputnik 1

Mission Profile

Sputnik 1 is the world's first artificial satellite, launched on 4 October 1957 from Baikonur Cosmodrome aboard a modified R-7 ICBM by the Soviet Union, marking the dawn of the Space Age. The 83.6 kg polished aluminum sphere, just 58 cm in diameter, contained two radio transmitters broadcasting on 20 and 40 MHz, whose beeping signal was detectable by amateur radio operators worldwide. Sputnik 1 orbited Earth every 96 minutes at an altitude of 215-939 km before its batteries died after 21 days, and it reentered the atmosphere on 4 January 1958 after completing 1,440 orbits. Its launch shocked the Western world, triggered the Space Race, accelerated US space investment, and irreversibly transformed the Cold War competition into a contest for scientific and technological supremacy beyond Earth.