Artwork of the Sputnik 1, the first artificial satellite which was launched in October 1957. It had a spherical shape (58cm in diameter) made up by polished aluminium and weighing 83.6kg. The Sputnik 1 carried four whip-shaped aerials 1.5- 2.9m long which were used to send signals to earth-bound stations. Radio contact with the satellite was maintained for 21 days; the Sputnik 1 decayed on January 4th 1958 after 1400 orbits around the Earth.