A better example is “Miri.” In “City on the Edge of Forever,” they were on Earth. In “Miri,” they used the same set but were on “Earth II.”
Although it is widely cited as possibly the best episode of the series, and I agree that it was well done dramatically, especially in not pulling its punch with the ending, I find it ironic that the best episode completely abandoned the basic premise of the series. Here we had a series that was supposed to “explore strange new worlds, to seek out new life and new civilizations. to boldly go where no man has gone before!”…and yet they end up on Earth in the 1930s. It was a time travel story, not a space exploration story.
I did not know that. You just made my day. Thanks.
In fairness, they found that portal to 1930s Earth when they were looking around on what, to the best of my knowledge, was a strange world where no man had ever gone before.
But that was just a way to shoehorn the episode into the premise. It was irrelevant how they actually got there.
You know what they said about Adam-12, that it condensed many hours of tedium into the few exciting instances of police work. Serving on a NCC-class starship involves days upon days of boredom, cribbage, things that cribbage might be a euphemism for and interesting discoveries that a television audience would not even begin to understand (too nerdy or just too off-the-charts to explain).
Any little thing that can be milked for drama will obviously end up in the show and probably be severely distorted for maximum effect. So, some of the stuff we see has to be made reachable and palatable to the viewers. What actually happened on the Guardian’s planet most of us will never know, but there is something there that Star Fleet really, really does not want us to know about.
That’s all completely irrelevant to my point.
I just watched ‘Undiscovered Country’ or whatever. What the fuck was that???
Slightly off-topic, but all this is at this point.
See this commercial which merges footage from Star Trek and Andy Griffith Star Trek / Andy Griffith Show - Mash-Up - MeTV - YouTube
Well, it was slightly better than The Final Frontier.
That’s about it.
(it was probably better in its original Klingon. 
)
There’s a quote from Dorothy Fontana (in one of David Gerrold’s books, I think) where she says (in regard to “Journey to Babel”) to eliminate all possibility of the inevitable horde of siblings showing up, she arbitrarily decreed that Spock was an only child.
I don’t recall if she included half-siblings in that decree, but she sure should have! 
‘To stamp out all the obvious stories in which half a horde of Spockian brothers, sisters, half-brothers and half-sisters showed up, I arbitrarily decreed he [Spock] had no other siblings. And, in my own mind, this vastly strengthened the drama in the conflict between Spock and his father in Journey to Babel’.
Thank you! 
No problem.
You know, I’m not sure I’ve ever gone through and checked before, but: the first episode aired was, what, them making the rounds so McCoy can administer the annual checkup to Robert and Nancy Crater, who’ve been living there for five years and meeting with ships as scheduled? And the season finale was them visiting the planet where Kirk’s brother has been working as a research biologist? And, in between, they deliver a shipment to the Tantalus rehab facility; and they check in with an established mining colony; and they respond to a call from one of Earth’s observation outposts; and there’s a layover at a starbase, for court-martial proceedings; and they head to Talos IV, where Pike and Spock has gone before, and…
…hang on; is this episode, with them looking around on a strange new world that’s home to the mysterious Guardian of Forever, actually among a minority of episodes that even involve the basic premise instead of them just visiting some space station that’s beset with Klingons and Tribbles, or transporting the Vulcan ambassador to a conference, or whatever?
That is nothing compared to the Camelot video.
You’re nitpicking and ignoring my main point. The episode wasn’t really about the planet. The Guardians were just a set up to bring them to Earth in the 1930s. It would indeed have been an interesting episode if we found out more about the Guardians, but we didn’t. At least in those other episodes, even if they were not exploring new planets, the major part of the plot involved visiting other planets or meeting aliens. They were space travel stories, not time travel stories.
No, I get your point — and, granted, it’s an interesting one — but I can’t help but note how often they don’t even do that much: they’re just delivering medical supplies to the asylum where Fleet Captain Garth has been getting treated, or they’re bringing Spock home to Vulcan for some kind of wedding ceremony that might also be a gladiator deathmatch, or whatever.
I agree that they pretty much abandoned the exploration premise in short order. Instead of the Enterprise being an exploration vessel, often they were just used as a special delivery service, emergency response team, or ferry for diplomats.
Not to mention how often Kirk declares in the captain’s log that the ship is “on patrol.” I don’t really think of patrolling as being an appropriate task for a “research and exploration” vessel.