This can be anything from Hyperspace in Star Wars, Warp Drive in Star Trek, travel through the Warp in Warhammer 40k or anything else.
I’ve always liked “slow” FTL travel, where going a few light-years still takes a few days or so. I also really like travel through an alternate dimension like in 40k, Event Horizon, Witchspace in Elite Dangerous.
I wanna know your favorite versions, or do you prefer stories that obey the laws of known physics, like the Expanse or Rimworld?
One of the first things we hear Pilot say in the first episode of the show is [D’argo ripping the bits out of the control console to remove Moya’s slave collar caused damage ] “Leading to our current top speed, which is barely hetch 2.” So through…whatever means Moya can propel herself at “hetch” speeds, usually in excess of “2” but that leviathans are also capable of a unique thing called a starburst. Which depending on the episode is either an instantaneous experience or a state the ship spends at least a little time in.
Again, Farscape is extremely soft sci-fi. Rigel somehow farts helium. He doesn’t eat food that contains a lot of helium, yet he farts helium. That’s the approach to science taken by Farscape. There’s more than a little actual magic in the show. It’s a show mainly about its characters and how they cope with (usually ridiculous) situations.
The helium thing is certainly true, but I don’t think the FTL stuff is related to hard- or softness. FTL is impossible, so it’s not like you can give details on the proposed method which make it more realistic.
Maybe you’re thinking of another series/canon where FTL travel is presented in a way that would qualify as “hard”?
I’m trying to think of any TV series with hard sci-fi rules actually - I think the medium is unsuited to it, with its varying writers.
Mind you it’s a scale. Star Trek is harder than Star Wars, which is harder than Farscape. I think the hardest sci-fi out there is going to be The Martian. We could plausibly fly an Ares mission as depicted in the book, the main technology handwave is the lack of thin, light, radiation shielded fabric for EVA suits and Hab canvas.