Star Trek: The Original Series the 23rd century bearing a crew dedicated to exploring the Milky Way Galaxy. Roddenberry noted a number of influences on his idea, some of which includes A. E. van Vogt's tales of the spaceship "Space Beagle", Eric Frank Russell's "Marathon" series of stories, and the film "Forbidden Planet" (1956). Some have also drawn parallels with the television series "Rocky Jones, Space Ranger" (1954), a space opera which included many of the elements that were integral to "Star Trek"—the organization, crew relationships, missions, part of the bridge layout, and some technology. Roddenberry also drew heavily from C. S. Forester's Horatio Hornblower
Star Trek: The Original Series show. "Star Trek"s first-season ratings would in earlier years likely have caused NBC to cancel the show. The network had pioneered research into viewers' demographic profiles in the early 1960s, however, and, by 1967, it and other networks increasingly considered such data when making decisions; for example, CBS temporarily cancelled "Gunsmoke" that year because it had too many older and too few younger viewers. Although Roddenberry later claimed that NBC was unaware of "Star Trek"s favorable demographics, awareness of "Star Trek"s "quality" audience is what likely caused the network to retain the show after the first and second seasons. NBC