Multiple FTL Types in same setting?

[Timerover51]

Easily nerfed by requiring more fuel than jump takes...

No, Aramis, I am not letting you get away with that comment.

EXACTLY WHERE IS ALL OF THAT ENERGY GOING? YOU ARE TALKING ABOUT TONS OF LIQUID HYDROGEN.

For a 5,000 dTon ship, for Jump-1, you are using 500 TONS of liquid hydrogen for a jump. Convert that to energy please before making such a ridiculous comment.

 

[BlackBat242]

Looking at the GURPS Space 3rd ed book which lists multiple FTL ideas, I thought how fun if the Zhodani with their emphasis on Psionics used a Psionic based FTL like described by the "Guild" in Frank Herbert's "Dune" or in SPI's "Universe" roleplaying game.

Sheewash drive.


* James H. Schmitz The Witches of Karres
Also the sequels written after his death by others, The Wizard of Karres, & The Sorceress of Karres

 

[Enoff]

Sheewash drive.


* James H. Schmitz The Witches of Karres
Also the sequels written after his death by others, The Wizard of Karres, & The Sorceress of Karres

Your vast knowledge BlackBat always leads me to something interesting

Plot summary
Captain Pausert, a well-intentioned, but inexperienced merchant traveler voyaging solo on the old pirate chaser Venture from the planet Nikkeldepain, is induced to purchase three young witches (Maleen, Goth, and the Leewit) who had been enslaved on the Imperial planet of Porlumma. The sisters were captured in a raid by Imperial slavers while visiting another planet on a jaunt of their own.

In getting clear of Porlumma, the Venture escapes belated pursuit with the use of the witches' klatha (psionic) Sheewash drive, which enables far faster transit of distance than is possible with primary or secondary space drives available either in or outside the Empire. This draws the unwelcome attention of both the Imperium and other governments to both Captain Pausert and the elderly Venture.

After returning the witch sisters to their homeworld, Karres, Captain Pausert attempts to return to Nikkeldepain, but is arrested before he can obtain permission to land. The Captain is informed that he faces a barrage of criminal charges, many relating to his encounter with the witches and his brief stay on the prohibited planet of Karres.

And they want the Sheewash drive. Avidly.

Captain Pausert escapes the Nikkeldepain police and military with the help of the middle witch sister, Goth, who had stowed away on the ship. From that point, he and Goth find themselves becoming more and more embroiled in wild adventures involving interdimensional alien invaders, space pirates, many more of the Karres witches, and assorted other characters.

from http://en.wikipedia.org/wiki/The_Witches_of_Karres

 

[aramis]

Unless it takes more than 100% of a ship's mass to go 7 ly, it's already chaged the universe.

I think you may be right, but it's not got to hit that much, as there's a rough minimum of 4% of hull simply to function (1%PP, 2% Controls, 1% crew space)

Lets see... 1LY/hr... it's 51x faster, but load and berth times aren't changed, so it's 7 days for a 1Pc run, instead of 14, on standard downtime routines. it needs only to take about 25 to 30% of hull in fuel per parsec to be economically less useful than jump for durables on ship...
Continuing with that 1LY/Hr drive... and assuming 33% of hull per Pc...

A MGT design 400Td should be using about 2.5% JD, 1.5% PP, 0.5% M1, 20% FJ, 1% FP, and 1% controls and crew. So, at 33% per Pc, it's able to get 2Pc and a little payload, and outpace J2, but it's likely to be less effective for Surface-to-surface.

It will then probably be used for LASH. System craft load on fixed route haulers, waiting to dive in, and we can get the number of sorties with that 33%/Pc fuel to roughly 4 per day, or 112x as many... 112x the trips, meaning the non-distance costs (which are about 75% of typical ops) are 1/112... call it reduced to 1% of base, but the fuel cost is about 1.7x, or about 42% of base... and the income reduce to 50-13=70%

33% is about half what we need.

Push it up to 70% fuel per Pc, you still get a useful cargo, but it's less cost effective than Jump for any non-information based ops. That's enough to keep it to 1Pc runs, still have a payload, and still have jump be price comparable.

You get a warp infonet, and jump shipping, warp warships and pirates.

Fundamentally, any additional drive has effects. Easily nerfed isn't the same as making no changes.

 

[rhialto]

Looking at the GURPS Space 3rd ed book which lists multiple FTL ideas, I thought how fun if the Zhodani with their emphasis on Psionics used a Psionic based FTL like described by the "Guild" in Frank Herbert's "Dune" or in SPI's "Universe" roleplaying game.

That's pretty much what the MgT book Psion provides.

 

[WistfulD]

Fundamentally, any additional drive has effects. Easily nerfed isn't the same as making no changes.

Good point, and granted.

 

[aramis]

No, Aramis, I am not letting you get away with that comment.

EXACTLY WHERE IS ALL OF THAT ENERGY GOING? YOU ARE TALKING ABOUT TONS OF LIQUID HYDROGEN.

For a 5,000 dTon ship, for Jump-1, you are using 500 TONS of liquid hydrogen for a jump. Convert that to energy please before making such a ridiculous comment.

that tone is hardly acceptable.

Especially given that we are talking FTL, for which the current math that is accepted (Alcubierre's) put the energy output to make it to Alpha Centauri at about half the total mass conversion of a star...

Edit for clarity: Dr. White's transformation of it isn't widely accepted - but it's widely hoped to be accurate.

 

[WistfulD]

Here's a question about the baseline (lowest possible) reasonable energy cost: Reducing reality to a high school physics problem, let's just look at the change in energy states, and assume the transition is 100% efficient. How much change in potential energy could someone (or predefined, X00 ton mass) gain or lose by moving over one lightyear?

 

[wbyrd]

I'm coming in late...as usual.

FTL comes in a few flavors Jump, Real Space, and "otherspace" FTL

They all have advantages if you use them in combination.

From a tactical/Military view..I can get into economics and political/social issues later.

Jump drives are secure, and hard to intercept, track since a ship isn't technically moving through the intervening space. Its draw back is you can get "lost real good" if the navigator forgets to carry the one.
By tweaking travel times you can alter the scenario even more. Fast or instant jumps such as BSG jump drives allow a ship to cross a lot of real estate in just a few seconds. Unlike Traveller jump drives which can takes weeks or months to move across a single sector.
Fast Jumps would seriously change the tactical and strategic considerations of a game. Jumping into a system to attack would be fairly straight forward but a fast jump scout courier could jump out ahead of the invaders alert a reaction force, and return in days not months.
My personal tastes have never been n favor of jump drives, slow or fast. The fast jump systems make things to easy. especially if short range tactical jumps are an option for a fast jump system. A ship can execute a fast jump and close into close combat range, or make an emergency jump to escape if things got too dicey.
Of course fuel/power requirements, navigation difficulties, and "spin up/cool down" times balance that out and make it a bit less likely that ships will be jumping all over the place during a scenario.

Then with jump you have to consider fixed or variable departure and arrival points. If a fixed jump point is needed to exit or enter a system, then a defender only has to set up a defense network to control those points. In reverse a ship would have to make it to a fixed point before it could jump out of a system and escape pursuit.
Rel space FTL is a can of worms. If you play it ard science ships have to have heavy armor or some sort of deflector array to survive getting sandblasted by dust, hard radiation, and impact with stray gas at superluminal speeds.
Tracking and pursuing a Real Space FTl Ship is fairly easy, detecting heat, gravitational distortions, ion trails etc make it likely a ship can be tracked by a pursuit vessel over long distances.
Detecting a ship coming towards you would be more problematic and would require FTL sensors or some sort of "Bow Wave" that precedes the ship to allow a defender to detect incoming FTL vessels.
Of course that advantage can be negated by the need for ships to slow down as they approach the inner system of a star where gas dust, gravel, and the odd planet/asteroid could ruin your whole day.
Then Defensively it would be much like Traveller where a system defense squadron or fighters would have time to detect, track and intercept hostile vessels before they got into firing range of a planet or station.

:CoW::CoW::CoW:Other space FTL where you physically leave normal space and enter a higher or lower dimension or alternate space is a huge can of worms,. The nature of the otherspace would determine far more than the technology to access the otherspace....actually that is such a can of worm I'll save that for a discussion all of its own.:CoW::CoW::CoW:

 

[aramis]

Here's a question about the baseline (lowest possible) reasonable energy cost: Reducing reality to a high school physics problem, let's just look at the change in energy states, and assume the transition is 100% efficient. How much change in potential energy could someone (or predefined, X00 ton mass) gain or lose by moving over one lightyear?

Depends what's at both ends, and the current vector.

 

[Blue Ghost]

wbyrd; I think the real-space FTL tech assumes that since you can move faster than C in normal space, then you have other devices that also move faster than C.

Touching on original series Star Trek, one of the big explanations there was that the engines produced so much thrust through matter-antimatter collisions, that the ship "rocketed" to its next destination. That was circa early from the time the show was produced to mid 70s.

After that people started to think about spacial anomalies, and how to apply loopholes in physics to Trek-tech. Ergo you get the explanation that Star Fleet's vessels (i.e. the Enterprise) take apart the fabric of space immediately in front of the ship, and reassemble it behind them, which gives them the actual "thrust"; something akin to a submarine using a pump jet through the warter. The idea being that you use the medium that you're travelling through to push you along.

With the second option your bow wave analogy is apt. Again, at the risk of repetition, the concept is that if there's something moving through space, and you have technology that can associate and interact with the fabric of space, then, by the standards of the fiction, it seems likely that the science would support detection capable of warning of an oncoming vessel or fleet.

I think the same can be applied to Hyperspace / Jump Space, or some other worm-hole like drive system. If you can get into that alternative space, then you can probably "see" what's around you with normal sensor suites. For even though you're travelling FTL in respect to normal space, the alternative space you're in is probably bound by the same "no faster than C" physical limit.

Just my thoughts.

p.s. I don't recall BSG using jump drives, but that's my 1980s memory at work. Is the new series different?

 

[whulorigan]

Touching on original series Star Trek, one of the big explanations there was that the engines produced so much thrust through matter-antimatter collisions, that the ship "rocketed" to its next destination. That was circa early from the time the show was produced to mid 70s.

After that people started to think about spacial anomalies, and how to apply loopholes in physics to Trek-tech. Ergo you get the explanation that Star Fleet's vessels (i.e. the Enterprise) take apart the fabric of space immediately in front of the ship, and reassemble it behind them, which gives them the actual "thrust"; something akin to a submarine using a pump jet through the warter. The idea being that you use the medium that you're travelling through to push you along.

Except that the original ST:TOS 1st Pilot "The Cage" has Lt. Tyler specifically saying to the "castaways" on Talos IV that they won't believe how fast they can get back, because the "time barrier" has been broken. And Captain Pike proceeds to the Talos Star Group with the command: " . . . Engage Hyperdrive - our Time-Warp, factor 7. "

In the ST:TOS 2nd Pilot "Where No Man Has Gone Before", after they encounter the galactic barrier and barely escape, in Kirk's log entry voice-over, he says: " . . . our space warp capability - gone. Bases that lay days away now lie years in the future . . ".

So the idea of warping space for FTL-travel was there from the very beginning.

p.s. I don't recall BSG using jump drives, but that's my 1980s memory at work. Is the new series different?

The Old BSG didn't really explain their mode of FTL Travel (that I recall). The New BSG explicitly uses an "instantaneous" Jump Drive.

 

[WistfulD]

Depends what's at both ends, and the current vector.

Riiiiight. How much? Assuming the jump rules on gravity wells, so you're not moving, say, just off the event horizon of a black hole or other immediate gravity well, but from one randomly generated star system to anotherwith 1-6 ly, how much change in potential energy could there reasonably be?

 

[Silverhawk]

I think the same can be applied to Hyperspace / Jump Space, or some other worm-hole like drive system. If you can get into that alternative space, then you can probably "see" what's around you with normal sensor suites. For even though you're travelling FTL in respect to normal space, the alternative space you're in is probably bound by the same "no faster than C" physical limit.

Weber's Honorverse had a very limited range for sensors while in hyperspace. about 20 light-seconds as I recall. That was in the best conditions. Typically could be a lot less.

 

[Blue Ghost]

« whulorigan »; sure, but it had a slightly different flavor than the late more "detailed" explanations that seemed to come from the fans who were scientists.

Silverhawk; yeah, I 've only read the first book, and got about half way through the second, but I can't remember much of the explained tech base, although combat (from I've read) took place in real space.

wybyrd; just to correct my previous post, I meant to say that since there was FTL drive tech that perhaps there were devices that could detect things operating at FTL velocities by means of interacting with some kind of FTL medium or output that could send back data faster than C.

I thin back in the 90s I heard about how C was not the actual fastest speed ever, but that the aggregate sum of the X and Y components of a carrier wave were actually found to be faster than C on a wave that was travelling at C.

 

[Marchand]

Off topic, but I was really impressed with the way Alastair Reynolds manages to do star-hopping space opera with no FTL (revelation space). Just cold sleep, relativistic time dilation, and a degree of plot control that RPGs don't really allow.

 

[PsiTraveller]

Psion Book

If you implement the Psion rules from Mongoose you can get a massive change in the game.

There are a couple of ways to change things. The first is Drive Augmentation. You will need a better computer, and your J1 engine can now get to J5 or 6 depending on how many points you spend. This saves fuel and money. A J2 ship could go two augmented jumps to get across a rift easily with fuel on board.

The other is folding space, this removes the need for Jump Drives altogether. The Psion creates a thought bubble, the ship uses M Drive to go into it, and a week later it pops out of the Folded Space at the destination. You can save a lot of tonnage for cargo that way. Tonnage will be lost to the support systems for the Psion, depending on what tech you use. It can be a simple computer to an 11 ton tank.

Psi Strength is an issue, with ship size being limited to 100 tons per Psi Point. This opens doors to Tapping and outrageous Strength numbers. YMMV.