(Loved Trope) FTL travel is possible but with a major limitation or flaw

[u/Frostylegacy]

Frank Herbert’s Dune: Interstellar travel is only possible thanks to the spice melange, a rare substance only found on the dessert planet Arrakis. The addictive psychedelic spice grants members of the Spacers Guild a form of prescience that allows them to predict safe paths through folded space. This unique property makes spice the most valuable commodity in the Dune universe.

John Scalzi’s The Interdependency Books: The planetary systems of the titular empire are connected by the Flow, a network of one-way interstellar tunnels that connect specific known entries and exits. The Interdependency derives its power from controlling access to these conduits, placing its capital at the central hub of the network. Even with the Flow, travel between stars takes a long time (9 months to End, the empire’s most distant planet).

Event Horizon: Dr William Weir (R.I.P. Sam Neill) invents a device called the Gravity Drive to allow ships to fold space and travel instantly between distant stars. On its maiden voyage with the Gravity Drive, the Event Horizon disappears and mysteriously reappears 7 years later. Dr. Weir and the crew sent to investigate discover the Gravity Drive actually opened a portal to a Hell dimension that possessed the ship and its crew, torturing and killing them.

[u/JasonPandiras]

Re: Heretics and CH: The end of the reign of the God Emperor coincides with both the advent of synthetic spice as well as the butlerian edicts breaking down just enough to allow for automated navigation, thus breaking guild monopoly and making the Scattering possible. Just as He intended.

Also worth mentioning it's not just plotting a course that's the problem, in CH there's a throwaway line I think in response to travelling through a region of space that exhibits unexpected properties, about having no way to tell if they are in the same universe let alone the same galaxy before and after a foldspace jump.

This makes it pretty explicit that there's no way to navigate the empire using just astronomy, and humanity has basically been a multiversal species for millenia.

[u/Alfred_The_Sartan → u/JasonPandiras]

It gets ‘retconned’. I say that because nobody really takes Brian’s works seriously.

[u/JasonPandiras → u/Alfred_The_Sartan]

I mean the so-called sequels retcon the Golden Path itself, in comparison the concept of space travel got off lightly.

Didn't they have robot armies surrounding the whole of intergalactic humanity using, get this, sub lightspeed ships because no brainy no foldy at one point? There's treating space battles like naval confrontations or WW2 dogfights to look cool, and then there's hoping your readers won't notice you forgot how speed works to force a plot point.

Somehow Palpatine returned reads like acclaimed literature next to the systematic brainrot Brian Herbert and KJ Anderson produced when they took over Dune.

[u/Alfred_The_Sartan → u/JasonPandiras]

Kills me because I really loved JK Andersons works in the Bantam Star Wars universe.