In the late 1970's, Paramount found that its previously maligned franchise Star Trek was booming. Demand for the show's reruns, which had been purchased as part of its Desilu deal, was huge. A growing cult of fans had made the show successful, so Paramount saw an opportunity. It had previously attempted to startup a television network in the 1950's that had eventually failed to capture an audience. The huge success that Paramount was having in network television at the time made the studio think that it should try starting up a network again. And why not use its hottest property to launch that network? Thus the Paramount Television Service was born.
The network would launch with a reboot of Star Trek called Star Trek: Phase II. It would star most of the original cast (Leonard Nimoy wasn't interested) and would provide PTS with a recognizable program right off the bat. The network soon ran into trouble; Star Trek was proving to be an issue because of its hefty cost and production disagreements. It soon became apparent that the network wasn't going to work out.
Star Trek: Phase II became Star Trek: The Motion Picture, with Leonard Nimoy rejoining the cast and its original failure at NBC all but forgotten.