There's a link between UFO & Space 1999. Apparently, a sequel series - UFO2- was on the cards, set ten years later with Shado expanding moonbase, but it never happened. Some of the pre-production design work evolved into that seen in Space 1999. Likewise in Star Trek, a planned series in the 70's morphed into the movies, with some of the scripts being dusted off for the Next Generation. And for the new show Discovery the ship design looks an awful lot like one proposed for the Enterprise back in the 70's.