Campaign Space-tech Paradigms

[Figleaf23]

I'm building a TL9 Earth edge-of-the-stars campaign and I'm planning on a 'jump'-based model for FTL. The pseudo-theory behind it is that it works by the ship first approaching C by normal drives*, and then precipitating 'balast' from a massless energy-state to matter. This throws the vessel into a 'super-massive' state that thrusts it into 'subspace', i.e. space below/within the curvature of the universe.

The vessel in effect crosses a shorter distance than the distance between the two terminii of the jump. Better jump drives permit a sharper dive into subspace and thus a quicker trip. Better navigation determines how close to target the vessel emerges from subspace. (Edit: Also, I should add, the time in subspace varies with the distance between the terminii, but not in full proportion. Longer trips are relatively more efficient.)

I'm curious about:

(1) What plot, tech, play or whatever implications does anyone foresee from that paradigm, and

(2) What paradigms others use or have used for FTL in their space campaigns and how they worked out.


{*At TL9 I see it taking an acceleration of several months to get sufficiently close to C. Then TL10 (the local space standard) improvements, in the jump drive and normal drives both, bring that down to about a couple of weeks.}

[Humabout]

(1a) The obvious one is "Lost in Subspace" - the drive malfunctions and the crew has to figure out why and fix it.

(1b) First Constact

(1c) Emerge in an unknown place due to some natural phenomanon (i.e. supernova, black hole, subspace anaomoly, etc.)

(1d) To go where no man has gone before....

(2) I've not used it yet, but I'm a huge fan of Asimov's hyperdrive. It adds in a lot of interesting tactical stuff and gives a unique? edge for people with better technology.

I also like Babylon-% hyperspace and the traffic bottlenecks/limited accessabliilty issues it presents. I'm surprised they never dealt much with hyperspace-capable carrier ships, like the Guild transports from Dune.

(If you're going with hard TL 9, it'd probably take a lot longer than a month to reach near-c. Even with a TL 10 fusion torch at a constant 1 G burn, a ship would take two and a half months to reach even 10% c. Any greater accelleration and you're risking serious health problems with the crew. 1G constant is also convenient as it does away with the need for spinning modules or gravity tech.

Fuel-wise, remember the beauty of the ramscoop. It really saves on fuel. Only thing that ever struck me was how to have enough fuel to slow down after using the scoop to speed up.)

Hope that's at least mildly useful.

[Fred Brackin]

Originally Posted by Figleaf23

{*At TL9 I see it taking an acceleration of several months to get sufficiently close to C. Then TL10 (the local space standard) improvements, in the jump drive and normal drives both, bring that down to about a couple of weeks.}

Unless "several months" is about 10 or 11 you're not going to get very close to lightspeed with 1 G of constant acceleration.

You'll also need a superscience drive to do accelerate that fast for that long. To cut things down to a couple of weeks you're going to have to toss in even more powerful drives with acceleration compensation.

You're also going to be smack in the middle of the "planetbuster" zone of kinetic energy weapons unless this is a pseudovelocity drive.

You can do all this if you want of course but you're taking on a fair bit of baggage that I don't conisder really necessary.

[Fred Brackin]

Originally Posted by Humabout

(



Fuel-wise, remember the beauty of the ramscoop. It really saves on fuel. Only thing that ever struck me was how to have enough fuel to slow down after using the scoop to speed up.)

Ramscoops are okay if you want to do a lot of handwaving and ignoring of inconvenient data. The interstellar hydrogen around our solar system (for several hundred LY) is too thin for ramscooping as just one probem.

Slowing down isn't a problem though. Detailed sims of ramscoops make them look like much better brakes than accelerators. Sort of a magsail mode.

If you don't want to wrestle with any sort of probable TL9 drive you can call your drive a ramscoop but you might as well use reactionless drive stats.

[SuedodeuS]

I like the concept, although as has been mentioned the speed required is problematic. If I'm not mistaken, however, what you seem to want is FTL travel that requires a long STL "warm-up" before it works. Here's another idea - subspace-braking.

Essentially, researchers not only discover subspace, they find that it's possible to dump kinetic energy into it - more specifically, the velocity part of the equation. This is used for "subspace-braking," wherein a vessel rapidly dumps its kinetic energy into subspace in order to rapidly slow down without having to use precious fuel. It is theorized - and eventually proven - that dumping enough kinetic energy at one time can create a tunnel into subspace, and that an object can enter this temporary tunnel. Once in subspace, distances are greatly lessened (provided you did it right), and it is found that it's actually fairly easy to break out of subspace - it's getting in that's the problem (you could have particles that get out of subspace on their own be how researchers find it initially).

So, how much kinetic energy is enough? That depends on the mass of the object that needs to pass through. The best way to figure this out is to determine how long you want the typical jump-capable ship to take to get up to speed. Once you know that, find out how fast it would be going at that time, and thus how much kinetic energy it has, and voila, you've got it. The way the amount of KE necessary scales with mass depends on what relationship you want between jump-efficiency and size. If you want it equal at (essentially) all SM's, it scales directly with mass. If you want small ships to be more efficient (which I doubt is the case), it scales with the square (or cube, or greater) of mass; if you want larger ships to be more efficient, it scales with the square root (or cube root, or lesser) of mass.

This could have some big impacts on the way space travel and combat works. First off, you probably aren't going to have much interstellar "adventure cargo" (that is, stuff that you buy low one place and hope to sell high elsewhere). With the deliberate nature of FTL, you're going to be planning all travel well in advance. If the efficiency scales in favor of more mass, FTL ships are going to pack on as much cargo as possible before a jump. Heck, if you scale it enough in favor, you might end up with the oddity of ships loading themselves up with worthless scrap in order to be able to enter subspace faster and cheaper. Such scrap would likely be jettisoned while in subspace, which could lead to any number of problems - subspace junk that damages other jumping ships, or said junk re-entering normal space and damaging satellites, colonies, etc. before it can be dealt with. STL fuel costs per mission would likely drop - as it stands now, a good deal of a craft's fuel has to be burned in order to slow down at the destination. Using subspace-braking, you simply dump KE into subspace, allowing you to slow down more quickly and without burning fuel. This would also be useful in combat, particularly if you could vector* the K-dump. If you could also redirect (with loss) the KE with this method, you could also end up with some very impressive astrabatics.

Subspace-braking could also be used to justify KE-only Force Shields. This would cause most projectile weapons (although it wouldn't work on lasers, and probably not very well on particle beams) to be less useful, as some of their KE would be dumped just before reaching the target. Indeed, planet-killers and the like would be useless - with such extreme KE, a dump causes them to jump into subspace. Of course, I suspect you don't want too cinematic of a campaign, so only the direct use of subspace-braking (that is, simply slowing down) and its use in FTL travel would be available.

*I feel this warrants a bit more discussion. What I mean here is that, if you are traveling (in respect to some arbitrary point in space) forward at 100 m/s and left at 10 m/s, you could vector the K-dump to drop energy unequally from each - so you could drop to 98 m/s forward, 1 m/s left; or even 100 m/s forward, no left movement. If you can also redirect the KE, you could change the above situation such that instead of going 100/10, you start going 80/20. This might even go so far as to give you maneuverability on par with cinematic fighter spacecraft. You can also allow a ship to drop mass (by jettisoning cargo and the like) while sapping away its KE to move faster. This can also make for interesting munitions - large missiles that use this redirection to stop dead and "fire" a much smaller projectile at a ridiculously high speed.

[Figleaf23]

While realism is the default state, I am willing to include 'superscience' to acheive a desired setting characteristic. However, I want the superscience to be, to the extent possible, consistent in its theoretical premises and consequences. These responses so far are very helpful and I look forward to any others.

In the campaign Earth is TL9, while the rest of local starfaring races are TL 10. The campaign begins after First Contact. There is no galaxy girding civilization, and the largest multi-system political group known in the area has no more than a double-handful of systems. Earth has begun the process of claiming Alpha Centauri politically, with formalistic "permanent presense" (a patrol-base), though not with colonists.

FTL tech is actually TL10, but Earth has done it using the "Star Cannon", a station in space that creates the 'super-massive' state externally for vessels passing through it. This means no round-trip without bringing another Star Cannon with you (and there's only one when the game begins).

Regarding emergence from subspace, I haven't decided whether to build in some gimmick that prevents disasters like popping into suns, leave it to the navigators to get it right, or maybe have some means of 'seeing' out from hyperspace.

[GoodGame]

Technologies relating to better acceleration to the jump speed and better navigation of jumps would probably be central to a research/espionage/covert action campaign.

[Timolas]

It sounds like you have been doing a bit of this anyway, but I think it really helps to start with the question "what kind of game events and scenarios will I and my players have fun playing?"

If you want a lot of star hopping, and in a Firefly / Han Solo (aka the good bit of Star Wars) sort of fashion, then you probably won't want a single journey to take more than a week or so. Long enough for interesting things to happen en-route, but not so long that the crew are forever climbing into the hibernation pods.

If you want interstellar travel to be special however - and arguably it is the most special thing IN a space game - then longer trips, requiring more infrastructure - like your space cannon - are more appropriate. In such a setting I would suggest it is unlikely that the players own their own starship; instead they might be assigned to it Star Trek fashion.

Your notes suggest that this is the style you are looking for more than the tramp freighter version of space opera, and that is cool... But just be aware that you'll be making it hard for your players to operate fast and loose with the authorities, should they want to. And in the worst case, they may feel a little without freedom, if travel becomes too difficult. Basically it becomes less a case of them saying "where shall we go next?" and more one of you setting up a series of scenarios linked by the few feasible routes they can take through your universe.

[Figleaf23]

Regarding sub-space braking, I like the idea and it's the kind of underlying theoretics I want to have behind the scenery in this campaign. At the same time the particulars suggested seem a bit more complex than I want to manage, at least as a common element of FTL travel. For simplicity, I think I'll have emergence from subspace occur on a resulting 'weighted average vector' that takes into account the sum of matter within a defined area of emergence and sets the ship as near to motionless relative to it all as possible, giving greater weighting to nearer masses. The effect in play would be that for most purposes, you're not moving when you come out of jump.

However I do like the idea of kinetic dumping as a supplement to maneouver drives at a higher TL.

Regarding the extent of star-hopping, it is correct that this campaign makes that deliberately rare, particularly for the TL9 humans, but even for TL10 civilisations that are wealthy and egalitarian, the vast majority of populations will never experience interstellar travel. (However this is because of cost not because of a physics restraint on where TL10 ships can go.)

That said, intra-system space development and travel will be fairly common. Most mature inhabited systems will involve multi-planetary settlement supplemented by substantial off-planet infrastructure (mining in asteroids, military patrol stations, scientific posts, specialized purpose installations here and there). This set-up explains why I'll use a 'better than realistic' maneouvre drive model that in turn makes my FTL model less onerous (time wise) than it might otherwise be.