The show is set in the Milky Way galaxy , roughly during the 2260s. The ship and crew are led by Captain James T. Kirk (William Shatner ), first officer and science officer Spock (Leonard Nimoy ), and chief medical officer Leonard McCoy (DeForest Kelley ). Shatner's voice-over introduction during each episode's opening credits stated the starship's purpose:
Space: the final frontier. These are the voyages of the starship Enterprise. Its five-year mission: to explore strange new worlds, to seek out new life and new civilizations, to boldly go where no man has gone before.
The series was produced 1966–67 by Desilu Productions , and by Paramount Television 1968–69. Star Trek aired on NBC from September 8, 1966 to June 3, 1969 and from September 6th on Canada's CTV network. Star Trek 's Nielsen ratings while on NBC were low, and the network canceled it after three seasons and 79 episodes. Several years later, the series became a bona fide hit in broadcast syndication, remaining so throughout the 1970s, achieving cult classic status and a developing influence on popular culture. Star Trek eventually spawned a franchise, consisting of five additional television series, twelve feature films, numerous books, games, toys, and is now widely considered one of the most popular and influential television series of all time.