While the live-action Star Trek and its spinoffs continue to air on cable (and in syndication in some markets), the animated follow-up that Filmation produced in conjunction with Paramount for NBC in 1973 hasn't seen the light of day since a brief cable run on TV Land a few years ago.
It turns out that Filmation suits proposed that children be added to the Enterprise, to be mentored by Captain Kirk (William Shatner), Mr. Spock (Leonard Nimoy), et al, but series creator Gene Roddenberry would have none of that. Filmation eventually created a teen-populated space series, Space Academy, starring Jonathan Harris & Pamelyn Ferdin, 4 years later.
Right now, let's scope a sample of the episode, "Mudd's Passion", as Roger C. Carmel reprises his role as con man Harry Mudd:
The animated Trek lasted two seasons. Being that it was the first series that Filmation had sold to NBC, it set a high standard that the studio was rarely able to match. Only two other series lasted as long on the network----Flash Gordon and Sport Billy, the latter a midseason replacement series that seemed to hang around in the 80's. The late James Doohan (Scotty) would do some additional work for Filmation, particularly a supporting role in the live-action serial, Jason of Star Command, a component of Tarzan & the Super Seven, in 1978.