Why is an episode of Star Trek: The Animated Series the only adaptation of Larry Niven's Known Space?

With dozens of short stories and novels written by scifi icon Larry Niven and an awarding winning group of visiting authors, I noticed that Star Trek TAS episode Slaver Weapon is the only TV show or movie to visit Larry Niven's Known Space. Why haven't there been more page to screen adaptations?

Answer

I am slightly hesitant about answering a question like this, as most answers are likely to be subjective unless we can find an interview from a movie industry insider who says that Larry Niven stories are hated - which is very unlikely even if it were true.

I think that the problem is that Niven's stories are just not that easily adapted for the screen. I don't mean that I think they would not be cinematic - I would love to see Hollywood's vision of a Ringworld, or of the Smoke Ring and personally I love Niven's novels and short stories - they are great hard sci-fi and full of ideas. However I think it would be very hard to write a script against any of them without significantly rewriting them. Niven does use a lot of internal monolog and dialog to explain stuff, particularly the internal monolog is quite hard to turn into a movie. Then there is the issue that so many of Niven's stories are intertwined and are best appreciated if you've read the whole canon. Movies have to stand alone, and bringing in all that backstory would take time.

I think that Ringworld has been optioned before to be turned into a movie, but has never happened. If you look at the story it is a contrived series of events just to allow us to explore the fantastic idea of a livable ring around a star. If you follow the story as action however it is fairly dull - they assemble a team, they go to the Puppeteer home-world, they go to the Ringworld, they crash, they fly across a tiny fraction of it, have a few adventures, find some stuff and escape. Ringworld Engineers has a bit more 'umph' to the story, but it is very complex for a single movie and would have to start to tie in Protector too. They are great novels, but I think would probably make either very long or very confusing movies.

The best science fiction movies tend to have either no source material, or a relatively stand alone and a short-story or brief novel as a source. Of Niven's works, probably the non-Known-Space stories would be better candidates as they are designed to be stand alone works.

Philip K. Dick is probably the most visited sci-fi author when it comes to being source material for movies. There are probably many reasons for this ... but the fact that he wrote a lot of short, stand alone stories, with a relatively simple 'high concept' idea in them that can be adapted for a movie without religiously following the plot is probably a large part of that. The Soft Weapon story by Niven which was adapted for ST:TAS as The Slaver Weapon episode is a very close parallel to that.