Frederik Pohl , editor of '' Galaxy Science Fiction '' , wrote in February 1967 of his amazement that '' Star Trek '' s " regular shows were just as good " as the early episodes that won an award at Tricon in September . Believing that the show would soon be canceled because of low ratings , he lamented that it " made the mistake of appealing to a comparatively literate group " , and urged readers to write letters to help save the 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 canceled '' 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 instead decided to order 10 more new episodes for the first season , and order a second season in March 1967 . The network originally announced that the show would air at 7:30 – 8:30 pm Tuesday , but it was instead given an 8:30 – 9:30 pm Friday slot when the 1967 – 68 NBC schedule was released , making watching it difficult for the young viewers that the show most attracted
Tricon
24th World Science Fiction Convention
Star Trek: The Original Series