70s Dystopian Space Movie?

[ChocolateChipCharlie]

Came back after a long hiatus to post this, and got distracted by the surprise of seeing my terraforming mystery solved.!!

Anywho. Westworld got me thinking of Futureworld, which got me thinking of a movie I can't quite remember. I thought it had Peter Fonda and maybe Dyan Cannon in it, but looking through their IMDBs I don't see any possibles. Here's what I remember:

A man and a woman are inside a large, well appointed cave. Or maybe it's a large spaceship, I can't recall. It's supposed to be the future, possibly another planet that has been colonized. There's something going on everywhere else that made them have to be in there, but it might be nuclear war or a plague or something. Or maybe they're on a long voyage in space, fleeing the catastrophe. I can't remember. In my head the film is mid 70s quality, pretty slow paced, and I really thought it was Fonda and a blonde, and that they had quite a bit of non graphic sexy times, but I'm hazy.

Not sure if this is enough to go on. I don't think it was an obscure movie, I just can't place it and it's killing me. I even went through Burt Reynolds' film list looking for the possibly blonde actress, figuring Burt was in so many 70s movies with hot actresses that there must be a match. Farrah, Loni, Raquel, etc. No luck.

Does this ring a bell for anyone? Thanks in advance!

[Mofo Rising]

I think you're thinking of Quintet, one of Robert Altman's odder works, which stars Paul Newman.

They're inside because the world is frozen, and they're all playing a weird game where they don't really spell out the rules. It's extremely ponderous. I looked at my rating for the movie and apparently I hated it, since I gave it 1 star.

[JaseSF]

Possibly Saturn 3 (1980)???

[ChocolateChipCharlie]

Possibly Saturn 3 (1980)???

Ahh, that's it! I checked it out on YT and it's definitely that movie. I swapped Peter Fonda in for Kirk Douglas, which is understandable, but I was right about Farrah. Not sure how I missed it in her filmography. Now that I've seen it again I totally remember Harvey Keitel, but I have absolutely no memory of the giant robot. Wondering what kind of state I was in when I saw it, or maybe I just nodded off midway though.

Anywho, thanks a million!!