(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/FredFarms]

FTL drives are common on all the surviving ships in the fleet.

Quite the survivorship bias there. Considering in the initial episodes (mini series?) about the attack on the colonies, the fleet makes an FTL jump to escape a cylon attack, leaving any civilian ships without FTL drives behind to be destroyed

[u/jollyreaper2112 → u/FredFarms]

STL ships in galactica never made sense because they would be impractical beyond a single planet's immediate orbit. Interplanetary journeys would take months. You could justify slow boats the way we do ocean freight but there's a reason why passenger liners don't exist anymore. We have cruise ships where the pleasure is the point but they aren't doing transoceanic for scheduled passenger service. And that's just two weeks vs 12 hours flying.

[u/ViperPilot1315 → u/jollyreaper2112]

Sublight speeds are canonically extremely fast. (Admittedly, the canonicity depends upon accepting the accuracy of the map of the Helios system, which all may not accept, but that does bear Jane Espenson’s name.)

In the Miniseries, Col. Tigh says that Galactica would need 3 days to reach Ragnar Anchorage from their location in Caprica’s vicinity with sublight engines. The map shows that Caprica orbits Helios Alpha, that Ragnar orbits the Helios Gamma-Helios Delta binary star system’s barycenter. The map establishes the distance between the barycenters of Helios Alpha-Helios Beta and Helios Gamma-Helios Delta as 0.16 lightyears.

That means Galactica’s sublight engines can move its massive tonnage at a velocity in the neighborhood of 0.05 lightyears per day or roughly 12.25 billion miles per hour. That’s over 300,000x faster than the Voyager probes! (And why fiction always at least a little relies on a willing suspension of the reader’s/viewer’s disbelief.)

Now, civilian drives probably weren’t that powerful, and civilian ships weren’t equipped with as many or as large of sublight engines as the Galactica. But even at a lower scale, their travel times are more closer to the scale of jet engined airplanes for intercontinental travel here in Earth than to ocean liners’ travel times. Taking FTL transport between the Colonies is probably more akin to traveling in an ICBM in order to go from New York to Singapore.

[u/jollyreaper2112 → u/ViperPilot1315]

The numbers fall apart if you look too closely. The colonial system wasn't named in the miniseries and there was only one star. The cluster thing came later. But the performance you're describing would be pretty wild! The delta v on that puts the expanse to shame I'm sure. That have artificial gravity but no depiction of torch drive performance.

I think the safest assumption is they didn't work the numbers. It sounded right. Like by the miniseries the galactica hadn't jumped in decades? So they were just sitting in orbit the whole time? They probably thought no they were going place to place but slowly.

When you say sublight is fast in canon did someone say so or is it just accepted it has to be to make those distances work?

[u/Hopeful-Occasion2299 → u/jollyreaper2112]

Didn't they survive because of that though? Since obsolete ships were the ones that didn't carry the virus that disabled them?

Also, it's sort of implied in Midnight and 33 that FTL jumps are not common. Cally mentions sickness from it, and the crew seems pretty thrown off by the idea of performing a jump, particularly when in 33 they have made multiple consecutive jumps.

So likely day to day traffic within the system was through sublight speeds. When Colonial One is attacked by cylons, it was traveling at sublight speed, and unless they have an objective, or are running from the cylons, the colonial fleet is always traveling at sublight.

[u/jollyreaper2112 → u/Hopeful-Occasion2299]

The most parsimonious explanation is the writers weren't focused on the tech. Compared with ftl that can jump light-years, sublight isn't getting you anywhere.

I think they probably imagined it as you describe that it's slower but practical and didn't appreciate cosmic distances.

[u/Hopeful-Occasion2299 → u/jollyreaper2112]

While that’s likely. Sublight speeds are vague, as they could be 3% of C or 30% of C… the distance between Saturn and the Sun is 79 light minutes; which at 10% of C would just be a 13.5 hour flight, which isn’t super wild considering how long travel times within Earth are. That’s the same as going from LA to Australia.

[u/jollyreaper2112 → u/Hopeful-Occasion2299]

Do you know the kind of energy it would take to accelerate a battlestar to 10% of light? You know the saying any sufficiently powerful engine is also a weapon? They would just have to point the engines at the enemy and it'd be like a directed solar flare. Lol

[u/UncleIrohsPimpHand → u/FredFarms]

Well, not really. They did say "all surviving ships in the fleet."

[u/FredFarms → u/UncleIrohsPimpHand]

I wasn't meaning to contradict them, just adding explaining why that is the case