Sputnik 1 was humanity's first artificial satellite. The Soviet Union launched it into an elliptical low-earth orbit (LEO) on October 4, 1957. The successful launch shocked the world and ignited the Cold War space race that eventually led to landings on the Moon. Sputnik 1 orbited for three weeks transmitting radio pulses before its batteries died, then silently for two more months before falling back into Earth's atmosphere where it burned up.
