When it comes to TTRPGs based on licensed properties, there are some weird examples out there. Just recently there was a crowdfunded set of books based on the original Planet of the Apes movies, I was surprised in February by the announcement of a Tomb Raider RPG, and going back to the hobby's early days you can find such oddities as games based on Dallas and Ghost Dog: The Way of the Samurai.
Still, the latest announcement from publisher Modiphius is definitely the most obscure I've seen this year. Space: 1999 is based on the TV show of the same name, a UK sci-fi series created by Gerry and Sylvia Anderson (of Thunderbirds fame) that ran for two seasons in the '70s, and will use the 2d20 system (which you might know from the Fallout TTRPG) to enable adventures on Moonbase Alpha in the far future of, er, 25 years ago.
