Star Trek: Every* Starbase Ranked Worst To Best
5. Deep Space Station K-7
Deep Space Station K-7 appeared in The Trouble With Tribbles, and with the remaster of The Original Series, remains the only station of such design in the franchise. Matt Jefferies originally began a design of a central hub that would be surrounded by a habitat ring, which in concept sounds more akin to Deep Space Nine. However, Gene Roddenberry nixed this idea.
Roddenberry had contacts at the Douglas Aircraft Company, which in turn had designed several ideas for space stations they had pitched to NASA. One of these designs became the basis for K-7.
Though the original filming model has long since been lost, a new one was built for Trial And Tribble-ations. This was built by Greg Jein, based on a painstaking review of the original episode. This model housed some embellishments, like spacecraft added to a small shuttle-port in its base.
K-7 endures as one of the most popular designs from The Original Series. Though it made, technically, only a single appearance, it's legacy has continued through both fan productions - such as Star Trek: New Voyages - and canon appearances, of a sort. Eaglemoss produced a model of the station, an example of which was featured in the Star Trek: Picard episode Hide And Seek.