The Sputnik program (Russian: Спутник, Russian pronunciation: [ˈsputnʲɪk]) was a series of robotic spacecraft missions launche by the Soviet Union. The first of these, Sputnik 1, launched the first man-made object to orbit the Earth. That launch took place on October 4, 1957 as part of the International Geophysical Year and demonstrated the viability of using artificial satellites to explore the upper atmosphere.