The Dark Stars ATU

[Omnivore]

Dark Stars
an Alternate Traveller Universe setting

Dark Stars is a variant of the Hard Times/One Small Step setting. In Dark Stars, the only non-hard science fiction technology is the FTL travel mechanism. It is not a near future setting however, it is a far far future setting as the far-flung children of Earth try to rebuild past glories even though their ancient, now legendary if not forgotten, home world is lost in time and space.

The Dark Stars setting removes the following elements from Traveller: gravitics, nuclear dampeners, meson guns and screens, plasma/fusion guns, sandcasters, and psionics. Other elements remain but are changed quite a bit, most notably computers, electronics, certain power plant and drive fuel usage rates, advanced armors, and especially lasers. A few new elements are introduced, including materials technologies such as metastable metallic hydrogen and crystalline boron nitride nanotubes.

The largest shift in the setting beyond the technology changes and the lack of an Imperium, is that without a low cost to orbit solution, space stations and habitats are far more common. As far as the game itself goes, the biggest changes are in vehicle design and space combat.

Dark Stars (*will attempt* ) attempts to balance the desire for realism vs the desires for simplicity and playability without sacrificing science (too badly at least).

I'll be adding in a simplified variant of the Lares drive I posted in another thread to cover the FTL needs of the setting. The portion I'm currently concentrating on is the hull portion of vehicle design.

Feedback, ideas, critics, etc all welcome - hope this is of interest!

 

[mike wightman]

So spin for artificial gravity and low g manoeuvre drives it is then.

Not to mention very different space ship combat and much shorter space weapon ranges.

How will player characters get up and down from planets easily?

 

[Omnivore]

For priority freight (including most passengers) surface to orbit travel uses SSTO scramjets at the mid tech levels (AZHRAE or similar), lower tech would use either multistage chemical or improved shuttle style vehicles. At higher tech levels, perhaps a Fullerened Meta-Stable Metallic Hydrogen engine, or something like a LOX-augmented Nuclear Thermal Rocket (LANTR).

There are quite a few engines on the drawing board that are capable of operating in multiple modes, trading off Isp for raw thrust. Depending upon world and politics, you might even be able to use an Orion or Open gas cycle nuclear engine. I'm still batting around the ideas as you can see.

Another aspect of the answer to your question is that in many cases players won't need to go to the planet surface. In the more advanced systems, civilization is largely off planet due not only to STO costs but also to escape environments turned sour by war, accidents, or just nature.

 

[Omnivore]

Following up: SSTO starships

For world exploration, at the highest TL (12 in DarkStars) it should be possible to design a fairly small (in player range) starship with an airframe hull that can land and take off from a size 7 world with normal atmosphere. It will burn a *lot* of fuel doing so though! In fact, I'm considering adding a special type of drop tank - basically a balloon, to assist in STO operations.

It goes, to some extent, into how I'm envisioning space combat. The common drives at standard interstellar TL (10) and above will be trimodal drives capable of operating in high efficiency (low thrust), high thrust (low efficiency), and something akin to a HEPLaRish, very high thrust (extremely low efficiency) modes.

So while normal maneuver is in spurts of tenths of a G, when necessary, assuming fuel exists, it will be possible to kick up to perhaps 10x normal thrust levels for short periods. This is akin to an 'emergency agility' feature but only really effective with smaller ships and at the longest combat ranges due to moment of inertia concerns.

Btw, just to note, the proposed Lares FTL drive requires power not fuel so pretty much the entire fuel load is available for maneuver.

 

[mike wightman]

How about graphine cable based space elevators?

 

[Omnivore]

How about graphine cable based space elevators?

Definitely for the TL12 high pop worlds of any value. There is also the possibility of a ferris wheel conveyer at, I believe, a slightly lower TL - not sure on the tech requirement though.

 

[DangerousThing]

Btw, just to note, the proposed Lares FTL drive requires power not fuel so pretty much the entire fuel load is available for maneuver.

Forgive me if I've missed something, but doesn't power generally require fuel? Or are batteries efficient enough for this?
-
Jay

 

[Omnivore]

Sure, power - at least in the amounts required for Lares FTL - requires a plant that consumes fuel, but the power plant fuel consumption of a realistic fusion power plant is negligible compared to reaction mass quantities. Perhaps 1% of your total fuel load is power plant fuel.

Classic Traveller and most of the later versions drastically overestimate fuel consumption for fusion power plants.

 

[DangerousThing]

Classic Traveller and most of the later versions drastically overestimate fuel consumption for fusion power plants.

Agreed. On the other hand, this power supplies the M-Drives which should take more power. If you look at a large ship, it doesn't seem as if there is enough power produced in the power plant of CT to change the momentum that much.

In every sort of physically real space ship using technologies that we know about now, there is always a maximum momentum change that can be produced with a given amount of fuel.

I don't like CT's (and most of the following) emphasis on volume without thinking about mass for ship building. I realize that it makes it easier, but it's not that much more difficult to add the mass component.

 

[Omnivore]

Speaking of momentum... while pursuing realism, I thought it would be fun to modify agility (and for that matter spinal mount aiming) by considering the moment of inertia and a maximum main engine gimbal angle of 45 degrees. With length in meters, the approximate simplified equation looks something like:

Penalty = length^2*0.02357/length (rounded to nearest integer)

The angular acceleration desired in that assumption is 1 radian/s^2 and the penalty value is in standard gravities.

In other words, agility would equal maneuver drive G-rating minus the penalty.
Negative agility would give negative to hit mods for spinal mounts but not bonuses to be hit.

Considering even fuel wasting modes for higher thrusts from realistic drives, big ships are sitting ducks... unless of course, I've completely lost my mind.

Ok.. I did lose my mind; formula should simply be: Penalty = length*0.02357

Realizing multiplying by 0.02357 is pretty darned close to dividing by 42 this has to be the answer.

 

[Omnivore]

I've started a blog for the Dark Stars ATU at http://darkstarstraveller.blogspot.com/. The first post there is the overview and I'll expand on it as time permits in future posts. I'll probably still bring up some topics on this forum from time to time concerning Dark Stars in order to get more input.

Thanks
Omnivore

 

[mike wightman]

I'm looking forward to seeing more of this setting.

I've run a few campaigns set in the near future that use a much more "realistic" ship paradigm, using the CT rules.

I used the jump drive as the manoeuvre drive, with fractional g ratings for performance - 0.1 to 0.6 g and the jump fuel percentages for reaction mass in g hours.

Internal gravity was either via spun hull (using the standard CT manoeuvre drive as the machinery required) or constant acceleration.

 

[Omnivore]

Sadly Mike, I've copped out.

The more I worked to put realistic reaction drives into the setting for interplanetary travel purposes, the more play in the setting looked to become dominated by delta-V tables and calculations as well as extremely long transit times. It could be done but it would loose so much of the nature of Traveller in the process that, in my opinion, it would no longer be an alternate Traveller universe.

Still though, I am continuing to aim for a hard science fiction setting with a single piece of handwavium. It is just that the nature of that piece of handwavium has changed from being just an FTL drive to being a variant of a stutterwarp drive crossed with Alderson points. The details are here.

Reaction drives are still present but as an interface drive rather than an interplanetary drive. So I still get my atomic rockets but not quite in the way I had hoped.

Brian