The International Designator is an international identifier assigned to artificial objects in space. It consists of the launch year, a three-digit incrementing launch number of that year and up to a three-letter code representing the sequential identifier of a piece in a launch. In TLE format the first two digits of the year and the dash are dropped. For example, 1990-037A is the Space Shuttle Discovery on mission STS-31, which carried the Hubble Space Telescope into space. This launch was the 37th known successful launch worldwide in 1990.