Sputnik postcard Artwork of Sputnik the worlds first artificial satellite on a postcard issued by the communist government of the former Soviet Union The text translates as pioneer of the cosmic era Sputnik was launched on October th The name Sputnik is Russian for travel companion or satellite The body was made from highly polished aluminium alloy sphere measured centimetres in diameter and weighed kilos It also had four long antennas attached Sputnik transmitted radio signals back to earth for a period of days The success of Sputnik prompted the US government to enter the Space Race with the launch of Explorer four months later