The first satellite launched into space was Sputnik 1, which was launched into an elliptical low Earth orbit by the Soviet Union on October 4, 1957, as part of the Soviet space program. It was the first artificial Earth satellite and weighed 184 pounds, which was much heavier than anything the United States was developing at the time. Sputnik 1 sent a radio signal back to Earth for three weeks before its three silver-zinc batteries ran out, and it fell back into the atmosphere on January 4, 1958, due to aerodynamic drag.