Soap opera scifi with a space based civilization

Yes I'm waffling again.  The other day after some conversations I was about to just toss in the towel on the whole idea I'd had originally - or at least started with this time around.  A friend remarked that all scifi soap opera anymore is sailing ships in SPAAAACCEE.  That holds especially true for Traveller, it always has been that sort of setting.

When you start to introduce reality into the picture, or at least physics as we know it, even including some fringe physics, the fundamental barrier between soft soap opera scifi and hard scifi pops up and smacks you in the face.  Initially you might think it is all due to slower travel times but that isn't it, the obstacle is the civilization model.  Soft soap opera scifi concentrates on ye olde planetary civilizations connected by handwaviums.  Handwaviums because otherwise the cost of interface operations (surface to orbit) is *huge*. 

But wait you say, what about beanstalks, laser boosted launch, electromagnetic assists, etc?  Well all of that certainly helps, those solutions reduce the problems by an order of magnitude.  Too bad soft soap opera scifi settings require a reduction of at least two if not three orders of magnitude in interface costs.

Even worse, soft soap opera scifi includes what I call the wilderness scenario:  a relatively small and cheap trading ship that can travel surface to orbit, orbit to interplanetary, FTL between the stars, interplanetary to orbit, orbit to surface - all on one fuel load in a couple weeks time.  A few days later, refuel and do it all over again.   I cannot find a realistic solution to this scenario even with using rather severe handwaviums in the interplanetary realm.

The last attempt with the Quantum Skip drive handwavium and using a somewhat realistic LANTR variant reaction engine still requires 80% of the ship's mass - that's mass not volume - which leaves precious little mass for cargo (as a percentage of ship) in any design that would be even remotely small and cheap.  In fact, it'd be large and expensive, so large that it would probably have to use secondary 'shuttles' for the actual interface. That doesn't completely solve the problem either as now your shuttle has to make numerous trips.

At that point you realize that to keep anything remotely resembling the Traveller setting, you need to throw realistic physics out the window.  Switching to the 2300AD setting helps a bit but still requires more of a handwave than I really am comfortable with for any remote claim to a hard scifi label.  I'll admit it, at a certain gut level I don't care much for the stutterwarp idea.  Perhaps its the feeling that stutterwarp is more of a arm wave than a hand wave.  That and it puts the 'magic' center stage nearly all the time.

Way way back, though unfortunately the documents have been lost in time, I had been working on another hard scifi concept also named Dark Stars.  That first version of Dark Stars was so wildly different in setting that this time around, aiming for a Travelleresque setting, the only thing I borrowed initially was the name.  Well, turns out, maybe I need to borrow far more than just the name.

The original Dark Stars setting was so hard scifi that there wasn't even any FTL.  In it, mankind used what is now called brown dwarfs (and similar interstellar planetary scale objects) as stepping stones to the stars.  The idea came out of some astronomy reports regarding a few isolated but recorded instances of unexplainable obscuration of certain stars, the theory at the time was that the cause was planetary objects between small gas giant and true stars.  I believe this was an early observation of what is now called brown dwarfs.

Obviously in the original Dark Stars setting, civilizations around the brown dwarf stepping stones weren't planetary civilizations.  The setting's back story was that as mankind expanded into interplanetary space, civilization became less and less planetary bound until by the time deep space colonizes were first established orbiting the nearest 'dark stars' there were more people who lived their entire lives in deep space than those who had ever lived on planets.  After that point, planets basically became irrelevant except as possible sources of raw materials that could not be obtained from lesser gravity wells.  Even that slim importance fades away as technology progresses and it becomes cheaper to create heavy elements or replace them with lighter elements than dig and lift them out of a deep gravity well.

One interesting side effect of this model is that planetary defenses and slag weapons become irrelevant.  Another is that it is hard to wrap your head around it as it is so foreign to the way we planet bound think.  Evolution of civilization.

So the original Dark Stars setting ends up becoming a collection of hordes of space habitats clustering around energy and resource points in orbits that minimize the costs.  You might well have specialized facilities in addition to habitats, such as facilities orbiting fairly close to stars in order to turn stellar output into a stored form such as antimatter.  Other facilities might be in low orbits around gas giants engaging in various refining activities.  Yet others are situated near larger rocks or collections of rocks in various places engaging in the processing of raw materials.  Populations, and their habitats, are mobile.  They shift with changing trade patterns and perhaps for other reasons as well.  I'm reminded of the scifi story where I first encountered a form of the stutterwarp idea, hyper-assistance, in Asimov's classic Nemesis novel.  In truth that novel, along with a few others, really laid the seeds for the original Dark Stars setting in my mind. 

That first Dark Stars setting, while interesting, doesn't make for a good space opera on an interstellar scale.  Without FTL and with realistic reaction drives up to and including antimatter, the time scales are rather beyond the space opera norm by a few orders of magnitude.  The question of the hour becomes, what form of FTL would enable near space opera travel times between neighboring stars without widespread changes in the basic underpinnings of the setting?  Further, at what technological point should it become available?  Too soon and the setting doesn't have time to evolve to true planetary independent civilization, too late and the science becomes completely unrecognizable.

Before setting down the operational criteria for the FTL mechanism, it is a good time to realize something inherently different between the first Dark Stars setting and most all soap opera scifi settings.  In Dark Stars a solar system's population and infrastructure is spread out all through the system, with varying densities near various points of interest.  In traditional soap opera equivalent terms this turns every world into a Dyson's sphere!  Traveller RPG is basically a collection of Kardashev I worlds into a Kardashev II civilization; the Dark Stars setting is somewhere between that and a collection of Kardashev II solar systems into a Kardashev III civilization.  Population and energy usage in the Dark Stars setting are almost assuredly beyond those of core worlds in the Traveller OTU setting. 

Along with that, the scale of travel across a 'world' is far different, roughly 5000 to 10000 times greater.  It would be like being restricted to the speed of sail on each world assuming some relatively realistic fusion torch drive is commonly used in Dark Stars for interplanetary scale travel.   This suggests that, to maintain the interstellar civilization soap opera feel, the maximum travel time between two points of interest orbiting adjacent stars should be no more than around three times  the average 'across the world' travel time.  That is, if it takes a month to go from one side of the system to another, it probably shouldn't take more than three months on average to go from a point of interest in one system to another point of interest in an adjacent system.

While a standard soap opera setting can have pre-space flight technology worlds, in a Dark Stars setting that makes little sense.  There is a minimum tech level required to support civilization in space. In order to satisfy the evolution of civilization argument above, this tech level must be significantly less than that required for FTL travel.

In order for space opera style interstellar warfare to make any sort of sense, there needs to be some limitations on the FTL travel mechanism, either some sort of choke points, or some distance limitations, or both.  To allow for manageable multiple star system empires, our speed of information transfer needs to be restricted as well.  In the absence of FTL communications, the time for a packet of information to travel from one system to another through a third is expressible as 2Tt + 2Tc1 + 2Tc2; where Tt is average FTL travel time, Tc1 is communications between decision center and FTL courier, and Tc2 is the communications time between two FTL couriers, assuming that a single courier cannot be used as quickly as two.

If we consider our elapsed time for scale of travel desired and our elapsed time for interstellar communications desired, we can calculate how long our FTL travel between two adjacent star systems should take on average.

Now zooming out a bit to look at the shape of an interstellar civilization composed of a collection of space based civilizations, a few questions spring to mind.  First, what differentiates one star system from another as far as desirability?  Probably a combination of stellar type, availability of easily accessible hydrogen, and asteroid belts - the more the merrier, perhaps small planets and/or moons might also be a bonus as a raw material source.  Beyond that location, location, location.  Of course that depends on the topography of our FTL mechanism.  While still zoomed out at this level, consider the ramifications of the FTL mechanism's topography on interstellar warfare as well.

I'll probably choose the Alderson point-ish Lares region type of Quantum Skip drive as the general FTL mechanism since a bit of time and effort has already gone into it.  It also has a somewhat more hard-sciencey technobabble behind it.  If the FTL points occur at roughly the 0.001 m/s^2 gravity gradient radius, that would put them around 2.5 AU from the sun in our solar system.  That also puts them at a reasonable distance for the average travel time target given realistic thrust levels of high delta-V reaction drives.  Now this assumes that the average interstellar tech level is a bit higher than normally found in Traveller, but given that is also a target criteria, we should be fine.

One aspect of this setting is that it gives us a bit of a way out with regards to our reaction drives and our power plants.  We can sidestep most of the issues with magnetic bottle fusion and go to various forms of pulse mode antimatter initiated fusion. 

I'll have to take more time and consider the pluses and minuses with this idea further.  It seems to give a realistic hard scifi (with FTL exception) soap opera/RPG setting at the price of sacrificing the sacred cow of planetary based civilization.

Quantum Skip Drive, Lares reimagineered

The result of the 'name that drive' poll on COTI was the Quantum Skip drive.  In a quick review, I'd decided to get around delta-v limitations that were going to seriously undermine any Travelleresque nature in the Dark Stars ATU with the introduction of a second mode of the old Lares drive.  This second mode only works in interplanetary space as long as the gravity gradient remains above a certain rating.  Initially I had the yet to be named interim drive working exactly as the Lares drive between stars but in a sort of micro-jump fashion in interplanetary space.  This still left me with the need for reaction drives both near planets and beyond certain limits.

However, the more I examined it, the more I realized I was just complicating things for no good reason.  If you are going to have realistic reaction drives in any sort of plausible mid term future setting, you're going to have months long transit times.  If your setting cannot work with those times, then introducing a cheat mode of your FTL handwavium might as well just do the whole job from jump point to orbit.  You will still need reaction drives for planetary landings and atmospheric operations but you won't need to spend half the role playing session calculating delta-V's.

The stutterwarp drive in 2300AD fits the bill except for the interstellar travel speeds.  So functionally the Quantum Skip drive is identical to the stutterwarp drive without the speed boost of stutterwarp past the 0.001 m/s^2 gravity gradient.  Like 2300AD's stutterwarp it cannot operate effectively in gravity fields stronger than 1 m/s^2.  The second and major difference between the Quantum Skip and Stutterwarp drives happens at Lares points where the Quantum Skip drive can be operated in a second mode that, instead of making a jump of a few hundred meters, makes a jump between star systems.

The secondary, interstellar, mode of the Quantum Skip drive requires an energy pulse 1000x normal input levels.  It also emits a correspondingly higher entrance and exit signature.  Reconfiguring and charging up the drive for secondary mode requires anywhere from 20 minutes to an hour, depending upon available power.  Reconfiguring, cooling, and properly discharging any stray accumulations of energy upon exit require a minimum of 20 minutes.  Note that unlike stutterwarp drives in 2300AD there is no need to discharge 'gravity potential charges'.

One oddity of the Quantum Skip drive is that the skip always has a directional vector perpendicular to the plane of the drive's emitter array.  This means that in combat, changing facing is the same as changing movement vector and requires the use of reaction thrusters (or thrust vectoring of a ship's reaction drive if it has one).  This limitation has a great effect on any evasive maneuvering attempts as well as on targeting of any spinal mount or fixed forward facing weapon systems.

The largest effect on the Dark Stars ATU setting from this change is that the trade model gets a bit closer to that of stock Traveller and that combat is possible anywhere in interplanetary space.  Lares points become the choke points of the setting.  Travel between star systems requires 24 +/- 5 hours as before with Lares drive, and interplanetary times are governed by the maximum apparent (base) speed of 250000 m/s.  Note that this is quite a bit slower than 2300AD stutterwarp speeds.  It basically gives 1 AU per week in total movement.  (Note: this is subject to change as I work out the details for the design sequence.)

Reaction drives aren't totally gone, just relegated to interface duties.  The preferred reaction drive will be the advanced trimodal NTR scramjet design in the current design sequence.  So I still get my nuclear rockets, just not quite the way I thought!

FTL Revisited - an alternative to Lares

I like the Lares drive idea, of course it's derived from Niven & Pournelle's Alderson drive so quite a few others seem to like the general idea too.  However, there's a problem.  Without a Langston field device, power levels are lower for both electrical and propulsion needs - also radiation shielding is a problem.  So, especially early on in the Dark Stars setting, our poor carbon nanotube hulled and nuclear thermal rocket propelled spacecraft end up spending lots of fuel and time to get to a Lares region.

Now I've tried bending and redefining the Lares drive idea a bit but it still ends up with around three months average per system at the lower tech levels just to pass through.  Twice that or more if you have to refuel!  I thought about putting refueling and trade space stations near Lares regions but they need a fairly extensive (and expensive and fragile) investment in station keeping hardware and need quite a bit of mass devoted to heavy duty storm shelters since they're around 0.6AU from the sun in our solar system, and it is quite possible some systems would have higher radiation levels at the equivalent gravity gradient.

It is still possible to make Lares drives work in the setting, but it is starting to look borderline.  So, since given the choice is change the current handwavium or add more handwavium to alleviate the problem, I started looking around for other FTL ideas.

I have a personal preference for point to point FTL, though I don't like forms that can be blockaded with minefields or that require an infrastructure in place.  Put another way, I don't like 'go anywhere' drives.  The reason is there are no choke points between harbors and surprise attacks are way too easy leading to widespread planetary destruction as the order of the day in warfare.  Makes for a rather ugly story.

The stutterwarp idea as given in 2300AD and as alternate rules in FF&S is an interesting one but at the expense of pretty much eliminating interplanetary travel by ordinary means.  Worse, it ends up taking space combat in a completely different direction.  A good idea overall, but too pervasive for the Dark Stars setting.

Another option would be a version of the standard Traveller jump drives that take no fuel and have a gravity gradient threshold that puts them further away from planets for transitions to/from J-space.  That is an attractive option except for one small wrinkle.  Without the need for refueling between jumps, there are no longer any choke points.

My original idea for Lares drive was to give a nod to physics and relativity by restricting travel to that between causally 'safe' gravity wells.  To escape the need for a Langston device, I invoked quantum physics handwavium and used virtual wormholes in the quantum foam.  So, while admittedly a huge hand wave, it at least didn't break anything.

Since then I've run across another fringe physics theory that, while admittedly non-mainstream, gives me a little more wiggle room.  It is called Lorentzian Relativity, alternatively LET, which basically says special relativity is wrong in respect to the non-existence of a special frame.  Interestingly enough, there's nothing except Occam's  Razor to choose between the two theories given current knowledge.  You can, of course, spark a flame war quite easily by bringing up that point on any physics forum.  Of course, with the existence of a preferred frame, causality problems vanish!

So handwavium theories in place to excuse some pretty strange departures from commonly accepted physics in regards to FTL, what can we make of them that solves our need for FTL travel in Dark Stars ATU better than the Lares drive?  How about a hybrid Lares/Jump/Stutterwarp?  Heh!  Rube Goldberg physics, here we come!

Let us suppose that around each star there are two hollow spheres.  The inner has a radius at the 0.024 m/s^2 gravity gradient, and the outer has a radius at the 0.00024 m/s^2 gravity gradient.  Further, let us suppose that if you extend a tube with a radius of say 50 light seconds or so (0.1 AU) between the outer spheres of two adjacent star systems, the intersection of the interior of the tube with the surface of the outer sphere (give or take 0.1 AU) defines a safe path entrance/exit thru L^-1 space between the two stars for our new drive.

Sounds a lot like the original Lares drive mechanics or Alderson points so far right?  Now for the wrinkle.  Inside a star system, while within the boundaries described by the surfaces of the inner and outer spheres and not crossing the 0.00024 m/s^2 boundary of any local objects, the same drive can be used to access L^1 space.  However where L^-1 space effectively gives a large multiple of light speed, L^1 space gives a small fraction of light speed.

What does that mean in English?  For our solar system the radius of the inner sphere would be about 0.5 AU, the radius of the outer sphere about 5 AU, and no closer than 100 diameters of Earth (3x moon orbit).  In system jumps travel 100 light seconds (0.2 AU) in 24 hours.  Jumps between systems take about 24 hours.

There is an important artifact of jump space entry/exit, namely a burst of energy biased in the direction opposite the direction of the jump.  Another limitation is that L^1 space has a fixed jump distance of about 100 light seconds.  Incidentally, it takes just as much energy for each L^1 jump as each L^-1 jump, and just as much calculation.

So what happens if you engage this drive outside of the prescribed limits?  No one knows.  Every time it has happened the craft disappears with an omnidirectional burst of energy and never returns.  Another failure mode is a little more common, at least in wilderness travel, and that is due to the poorly understood but nonetheless true fact that not all star systems have connections to all neighbors.  In this second failure mode, the craft disappears with an omnidirectional burst of energy, and about 24 hours later returns in the same spot.  There are also suicidal paths that have exit regions in non survivable environs, and there are the rare but verified one way paths. 

So, our new drive, without a name yet, acts as a restricted FTL drive between systems, and as a STL but still useful drive within certain limits inside of a system.  It doesn't require handwavium high Isp from our reaction drives in order to travel in space opera time frames, nor does it eliminate the need for either high Isp and high thrust reaction drives in normal space.  As a side note, this new drive, like the Lares drive, supposes that the energy spent by the drive is merely used as a lever to unlock energies at the quantum level, it is those unlocked/leveraged energies that perform the work.

See the name that drive poll over on CotI..

Update: currently under consideration is the idea of extending the in system operational limits to the 0.000024 m/s^2 gravity gradient which would allow a bit more access deeper into the outer system (nearly 16 AU which in the Sol system would put Jupiter and Saturn within reach and nearly close enough to Uranus for reasonable travel times by reaction drives).

Spacecraft design - C4ISTAR in Dark Stars

Overview

C4ISTAR is a British acronym for command, control, communications, computers, intelligence, surveillance, target acquisition, and reconnaissance.  It seems every rule set for Traveller takes a different approach to addressing this aspect of spacecraft design.  While classic Traveller basically just dumped it all into (rather oversized) Computers and Bridge, subsequent versions have broken it down into component parts with 18 different variations for each part.

Having spent most of my life in some part or another of the IT industry, classic Traveller's treatment of computers doesn't sit well and hasn't since the mid '80s.   On the other hand, I want to design spacecraft for use in a game, not specify subsystems for prototyping by a DOD subcontractor!  So the later treatments of this topic fall flat for me as well.  The root cause, for me, is that LBB2 was too detailed in this respect... that's right *too* detailed.

In Dark Stars I'm assuming that information technology is distributed throughout the various major systems and subsystems as well as the control areas.  A TL9 spacecraft has better IT than a TL8 spacecraft.  All electronic and computer systems on all spacecraft are automatically radiation hardened and fiber optic backbones for inter system communications is assumed from the get go.  So no need for installing a 'computer'.. zip.. nada.. whew!

There are really only two components necessary in this section, the bridge; which includes various miscellaneous aspects of the spacecraft design such as airlocks, perhaps maintenance access ways, power distribution systems, and C3 links.  Basically LBB2 already took care of this though I do think the minimum bridge size was a bit overboard.

The other component necessary in this section can be simply called avionics.  This component is a collection of the communications, intelligence, surveillance, target acquisition, and - with the help of drones - reconnaissance.  Yeah that's right - it includes sensors.  It also takes care of mundane aspects like.. avionics!  NOE capable avionics is assumed to be included with any airframe configuration spacecraft.  Avionics should be available in a few 'flavors' - basic, civilian standard, military/survey, long range military, and advanced long range military.  Other sets of names would work and that might be a little too many but it covers what needs covered, and covers it simply, smoothly, and without causing IT professionals to have indigestion.

Components

Bridge

The bridge includes crew stations for the on duty command crew as well as numerous miscellaneous aspects of the spacecraft, from airlocks to redundant C3 networks.  It also includes basic avionics.  Tonnage required is 2% of the spacecraft's wet mass.  Minimum mass is 10 tons.  Cost is MCr 0.005 per ton of spacecraft (wet mass).

Avionics

The avionics section includes sensors and communications equipment along with any necessary specialized computers for navigation and sensor data analysis.

Code	Description	Mass	Cost(MCr)	Mount points
0	Basic	-	-	-
1	Civilian	1.0	2.0	1
2	Military/Survey	5.0	10.0	3
3	LR Military	25.0	50.0	9
4	Adv LR Military	125.0	250.0	27

Note that Basic Avionics is included in the Bridge tonnage and cost.

And... that's all folks... C4ISTAR in Dark Stars.

Engineering Section

The Engineering Section

 Beyond the obvious technologies removed from normal Traveller for the Dark Stars setting, a few assumptions are made about the rate of progress with other technologies.  Among the most obvious of those is the delayed tech levels at which fusion power plants and drives become available.  In the Dark Stars setting, pulse fusion drives do not become a reality until TL11, fusion power plants follow a tech level later at TL12, and finally at TL13 the fusion torch drive becomes practical.

The Dark Stars setting also departs from standard Traveller in paying attention to waste heat management.  Power producing drives and power plants require radiator areas on the hull.  These come from the mount points calculated in the hull design sequence and are assumed to be armored with IR transparent variations of the hull armor.  The mass and cost of these radiators is included in the mass and cost of the drives and power plants.  Only the reduction in available mount points needs to be a consideration.

FTL

Quantum Skip Drive (QSD)

Quantum Skip Drives are available at TL10+.  While the operational characteristics of the QSD are quite different than traditional Traveller Jump drives, the representation is nearly identical to a Traveller Jump-2 drive.  The primary difference being the QSD requires no fuel (directly at least) and does not create a jump bubble of hydrogen nor require a jump grid of lanthanum on the hull.  It does require some surface space however for field emitters.  A QSD requires 5% of a spacecraft's wet mass at a cost of MCr 0.25 per ton of drive.  It also requires 5% of the spacecraft's mount points (round fractions up) for the emitters.  The drive requires 0.1 Mj per ton of spacecraft (current tonnage at jump time).  This energy must be provided over a period of not more than four hours, although if sufficient power is available, the drive is capable of being charged in a minimum time of 30 minutes.  Thus the power required is anywhere from 0.025 Mw per ton of spacecraft to 0.2 Mw per ton of spacecraft. 

Maneuver

Magneto Plasma Dynamic (MPD)

Available at TL8+, the mature version of the MPD engine has a variable Isp and in 'low gear' barely qualifies as 1m/s^2 capable requiring 10% of the spacecraft's mass (not necessarily its total wet mass) for the drive alone for each 1m/s^2 of acceleration.  In addition, a MPD engine requires 0.25 Mw per ton of engine to be supplied by the craft's power plant (regardless of mode).  The minimum engine mass is 5 tons, it requires 1 mount point per 100 tons of engine for nozzles (round up), and costs MCr 0.1 per ton.

Were it not for two features, the MPD drive would be extremely seldom seen, however because of them it sees widespread use for deep space and bulk freight applications.  The first feature is that it can use hydrogen, usually in the form of liquid hydrogen slush (LHS), as fuel as well as many other alternatives.  The second is that it has variable specific impulse, and while performance is abysmal at the highest thrust levels, over the long haul it is second to none.  In 'low gear' max thrust, the engine has an Isp of only 1800.  However, in high gear, while the thrust drops to only 5% of low gear, Isp skyrockets to 36000.

Low gear produces 1 ton of thrust and consumes 2 tons of fuel per hour per ton of drive.
High gear produces 0.05 ton of thrust and consumes 0.005 tons of fuel per hour per ton of drive.

LHS fuel costs Cr50 per ton.

 Metastable Metallic Hydrogen Augmented Solid Rocket (MMHASR)

Available at TL9+, the MMHASR is a solid fuel rocket technology that augments the chemical propellant with metastable hydrogen.  While originally employed as a secondary thrust agency (booster) for STO spacecraft, it has become the propellant of choice for modern missiles.  MMHASR has an Isp of 1200; divide the propellant mass by 3 to determine the thrust in ton/hours, maximum thrust in tons is 5000.  MMHASR propellant costs Cr 2500 per ton.  The minimum mass of a MMHASR engine is 0.5 tons.

  Trimodal Augmented Nuclear Thermal Rocket (TANTR)

The TANTR engines are the workhorses of the Dark Star universe.  While earlier primitive variants exist, the combinations of technology required for safe, reliable, and ecologically friendly operation combined with near theoretical maximum performance does not occur until TL9+.  The TANTR has three modes of operation, reactor mode giving no thrust but supplying power, cruise mode with an Isp of 1800 using Liquid Hydrogen Slush (LHS) fuel; and full thrust mode with an Isp of 1200, augmenting the LHS fuel with either Liquid Oxygen (LOX) fuel or compressed air (scramjet mode if available).  The nuclear fuel supply is included in the mass and cost of the drive, it is sufficient for one year's operation.  Refueling the nuclear fuel costs 10% of the total drive cost.

Each 1m/s^2 of cruise mode acceleration requires 2% of the spacecraft's mass (not necessarily its total wet mass, more commonly its combat mass or cruise mass).  In other words, each ton of TANTR produces 5 tons of thrust and consumes 10 tons of LHS fuel per hour.  In full thrust mode, each ton of TANTR produces 12 tons of thrust and consumes an additional 26 tons of LOX fuel per hour.  The engine produces a secondary electrical power output of 20 kw per ton in thrust modes and 100 kw per ton in reactor mode.  Each engine requires 1 mount point per 50 tons of drive (round fractions up) for the nozzle.  Radiator area required is 1 mount point per 2 tons of engine (round fractions up).  Minimum engine size is 10 tons.  Cost is MCr 0.1 per ton of drive.

Scramjet Mode:
TANTR engines may be equipped with scoops and compressors for scramjet mode operation, replacing half the LOX fuel requirement with compressed air while in a planetary atmosphere.  This modification adds 10% to the engine's mass, requires 4 mount points per ton of engine, and costs MCr 0.25 per ton.  This modification, while in operation, consumes all of the secondary electrical power that would normally be produced by the TANTR engine.  This modification may only be installed on spacecraft with streamlined or airframe hull configurations.

LHS fuel costs Cr50 per ton.
LOX fuel costs Cr500 per ton.

Anti-proton Initiated Pulse Fusion (AIPF)

A practical, reliable, commercially feasible fusion drive was a goal that frustrated countless researchers until TL11.  Even at TL11 it is considered by many to be a marginal technology as it relies heavily on infrastructure for both fuel and maintenance.  On the other hand, this drive type obtains an Isp of 36000 using specially manufactured metastable metallic hydrogen (MMH) pellets and mere nanograms of anti-protons.  Note that engine exhaust is highly radioactive.

Each 1m/s^2 of acceleration requires 5% of the spacecraft's mass (not necessarily its total wet mass).  Thus each ton of AIPF produces 2 tons of thrust and consumes 0.2 tons of fuel pellets per hour.  The engine produces a secondary electrical power output of 20 kw per ton.  One mount point for each 100 tons of engine is required for nozzle.  Radiator area required is 1 mount points per ton of engine.  Minimum engine size is 10 tons.  Cost is MCr 0.25 per ton of drive.  Sufficient anti-proton mass is included in the drive mass and cost for one year of operation.  Replacement of the anti-proton initiator fuel adds MCr 0.05 per ton of drive to the cost of annual maintenance.

MMH fuel pellets cost Cr 2500 per ton.

Magnetic Bottle Fusion Drive aka Fusion Torch

Finally arriving at TL13+, fusion torch drives rapidly become the engine of choice for those who have access to the technology required.  With an Isp of 36000 from a deuterium/helium3 (DH3) fuel mix, the fusion torch drive not only offers superior performance but adds the prospect of limited wilderness refueling operations.  Like the AIPF however, the engine exhaust is highly radioactive.

Each 1m/s^2 of acceleration requires 10% of the spacecraft's mass (not necessarily its total wet mass).  Thus each ton of drive produces 1 tons of thrust and consumes 0.1 tons of fuel per hour.  The engine produces a secondary electrical power output of 20 kw per ton.  One mount point for each 100 tons of engine is required for nozzle.  Radiator area required is 5 mount points per ton of engine.  Minimum engine size is 5 tons.  Cost is MCr 0.5 per ton of drive.

DH3 fuel costs Cr 5000 per ton.

Power

Nuclear Fission 

While earlier version are available at half the output, three times the mass, and five times the cost; at TL8+ nuclear fission power plants become the most commonly used power source in space until the arrival of nuclear fusion at TL12.  Fission power plants produce 0.125 Mw and cost MCr 0.02 per ton.  One mount point is required per 25 tons of power plant for radiators (round up).  Minimum power plant mass is 25 tons.  Large scale fission power plants, of at least 250 tons mass, have twice the power output per ton.  Fission power plants include sufficient fuel for one years operation, replacement costs 10% of the original power plant cost.

Nuclear Fusion

Finally at TL12+ nuclear fusion power plants become a reality.  Based on the deuterium/tritium cycle they produce 0.5 Mw and cost MCr 0.05 per ton.  One mount point is required per 5 tons of power plant for radiators (round up).  Minimum power plant mass is 5 tons.  Fusion power plants include sufficient fuel for one years operation, replacement cost is included in the cost of annual maintenance.  Fusion power plant efficiency varies with mass according to the following table.

Mass	Output modifier
25+	x1.5
50+	x2.0
100+	x3.0

Support

Fuel Tankage

Fuel tankage requires no additional mass beyond the fuel they contain but the tonnage must be specified at design time and costs MCr 0.001 per ton.

Fuel Refinery

Onboard fuel refineries can be installed to refine LHS, LOX, and DH3 fuel from liquids, gases, or liquified solids.  Each ton of fuel refinery can refine 0.1 tons of fuel per hour.   Minimum refinery mass is 10 tons.  Cost is MCr 0.01 per ton.  If fuel scoops are desired, add one mount point per 10 tons of refinery and double the refinery's cost.   Engines with a scramjet modification are assumed to already include fuel scoops.  Note that DH3 fuel is refined at 0.01x the normal rate.

Workshops

At a mass of 4 tons and cost of 0.25MCr per engineer, onboard workshops allow +1 to all repair attempts and allow a chance of ad-hoc replacement of  irreparably damaged components.

Frontier Upgrade

Drives (both FTL and Maneuver) and Power Plants may be installed which are modified for high reliability long duration service.  These components mass 50% more than normal and cost three times as much.  This upgrade gives +1 to all reliability check, +1 to all repair attempts, and extends  the service lifetime to three years.  If sufficient workshops are also installed, annual maintenance may be delayed without penalty to three years between overhauls.

Radiator Wings

Spacecraft which need additional radiator mount points may install up to two radiator wings.  Each radiator wing can provide an additional number of mount points of radiators up to a maximum of 50% of the spacecraft's normal mount points.  They mass 1 ton and cost MCr 0.1 per mount point of radiator added.  There are two options that may be used with radiator wings.

1) Retractable radiator wings.  If the spacecraft's configuration is not 0 (unstreamlined) it must use this option.  This adds 20% to the mass and cost of the wings.

2) Armored radiator wings.  The wings may be armored the same as the normal hull mounted radiators with IR transparent material. Calculating the added tonnage and cost of the armor is a bit involved.  Using the same armor rating as the hull, the armor factor for the wings is Ar * 4.  The structure rating for the wings is equal to Gt * Ga * 0.1, minimum of 1.  The wing material rating is then equal to Sr + Af.  The mass of the added armor is then equal to the radiator mass * Pc * Mr (see hull page).  The cost per ton of the added armor is twice the figure given in the armor table of the hull page.

Heat dumps

When the total deployed radiator mount points is less than the required radiator mount points, the difference represents points of heat that must be dumped (else the craft turns into a can of stewed crew).  There are two types of heat dumps, water ice dumps, and reactor coolant dumps.  Each ton of water ice vaporized and ejected removes one heat point.  Water ice heat dumps mass as much as the ice they contain and the water is essentially free.  Reactor coolant heat dumps are twice as efficient removing two heat points per ton vaporized and ejected removes two heat points.  However reactor coolant costs Cr250 per ton and may be difficult to replace in a wilderness setting.  Regardless of type, heat dumps cost MCr 0.001 per ton installed.

Notes

The above should be sufficient, at least to start.  The numbers, of course, may need to be tweaked.  Later on I'll probably add more to the power section: fuel cells, solar panels, and batteries are likely additions.  The big test will come in a few days (or weeks) when I try to design the Frontier Survey Cruiser I have in mind to help me flesh out the Dark Stars setting via solo play.

Update: The drives are currently being reworked, relatively minor changes but still needs cleaned up.

Hulls - Take 2 - Mass Effect?

Well, the first try at hulls wasn't too bad overall but wouldn't it be nice if the design of a reaction drive spacecraft could be entirely mass based?   Of course the automatic answer to that it yes, but what about hull plating/armor and surface area considerations?

After much searching and way too much reading, I may have come up with a... not solution but perhaps a workaround.  It seems that quite a few people who evidently are nearly as insane as myself, have calculated out the densities of various ships in Traveller.  The figures seem to mainly fall between 4 metric tons per displacement ton and 7 metric tons per displacement ton.  A value of 4 metric tons per displacement ton seems to be in the ballpark of the mass/volume budget I consider  right for the Dark Stars setting.

This figure might seem high at first, given that 50% of your average deep space craft's mass is in fuel with a density of  less than 0.1 but engine shielding and storm shelter shielding should go a long way to help make up for it.

So, if an average density around 0.29 metric tons per cubic meter is assumed, an enclosing hull can be designed for a given mass - which gives the surface area and hull plating/armor figures.  Seeing as how they are guesstimates anyhow, I think it might be worth a try.  While I'm at it, 1 m/s^2 seems a better fit to Dark Star as a drive rating than 2.5 m/s^2 so we'll refactor that in too.

Now the fun part is refactoring yesterday's hull design formulas into today's new and improved variant.

First we need a modified configuration table:

Code	Atmospheric rating	Hull cost modifier	Material structure modifier (Sm)
0	Non-atmospheric	1.0	1.0
1	Partial streamlining	1.2	1.2
2	Streamlined	1.5	1.5
3	Lifting body	2.5	2.5

Our structural factor formula becomes:
Sf = (Mt/4000)^(3/2); where Mt is the total wet mass of the spacecraft in metric tons.

And our structural rating formula becomes:
Sr = Sf * Sm * Gt * Ga * 0.1; where Gt is thrust in m/s^2 and Ga is agility in m/s^2 (Gt >= Ga >= 1).

Our minimum Sr remains 1.

Now are armor multiplier formula becomes:
AMV = 10/(0.25*Mt)^(1/3)

And our armor factor is now:
Af = Ar * AMV * Sm; where Ar is the armor rating.

Note that for now I'm going to punt on the exact definition of Ar.

Our minimum Af remains 1.

And our material rating (Mr) is still:
Mr = Sr + Af

The craft percentage by tech level now changes to include a base price per metric ton.

TL	Percent of craft	MCr per ton
8-9	2.0%	0.10
10-11	1.5%	0.15
12-13	1.0%	0.20
14-15	0.5%	0.25

Now the hull mass is given:
Mh = Mt * Pc * Mr; where Pc is the percentage of craft from the table above.

And the hull cost is:
Ch = Mh * Ct * Hcm; where Ct is the MCr per ton from the table and Hcm is the hull cost modifier.

Finally, because what I was formerly calling hardpoints may also be used for non weapon mounts, I decided to change the name to mount points.  The formula for determining the maximum number of mount points also changes:

Mp(max) = 0.75 * (0.25*Mt)^(1/2); where Mp is the number of mount points.
Turns out I need a new mount point formula, the correct one follows:
Mp(max) =  0.75 * (Mt)^(2/3); where Mp is the number of mount points

So the entire Mp(max) column in the following table is kaput.

Mass of craft	Sf	AMV	Mp(max)
50	0.01	4.31	2
100	0.01	3.42	3
150	0.01	2.99	4
200	0.02	2.72	5
250	0.02	2.52	5
300	0.03	2.38	6
350	0.03	2.26	7
400	0.04	2.16	7
450	0.04	2.08	7
500	0.05	2	8
600	0.06	1.89	9
700	0.08	1.79	9
800	0.09	1.71	10
900	0.11	1.65	11
1000	0.13	1.59	11
1100	0.15	1.54	12
1200	0.17	1.5	12
1300	0.19	1.46	13
1400	0.21	1.42	14
1500	0.23	1.39	14
1600	0.26	1.36	15
1700	0.28	1.34	15
1800	0.31	1.31	15
1900	0.33	1.29	16
2000	0.36	1.26	16
2500	0.5	1.17	18
3000	0.65	1.11	20
3500	0.82	1.05	22
4000	1	1	23
4500	1.2	0.97	25
5000	1.4	0.93	26
6000	1.84	0.88	29
7000	2.32	0.83	31
8000	2.83	0.8	33
9000	3.38	0.77	35
10000	3.96	0.74	37
12500	5.53	0.69	41
15000	7.27	0.65	45
17500	9.16	0.62	49
20000	11.19	0.59	53
22500	13.35	0.57	56
25000	15.63	0.55	59
30000	20.54	0.52	64
35000	25.89	0.49	70
40000	31.63	0.47	75
45000	37.74	0.45	79
50000	44.2	0.44	83
60000	58.1	0.41	91
70000	73.21	0.39	99
80000	89.45	0.37	106
90000	106.73	0.36	112
100000	125	0.35	118
150000	229.64	0.3	145
200000	353.56	0.28	167
250000	494.11	0.26	187
300000	649.52	0.24	205
350000	818.49	0.23	221
400000	1000	0.22	237
450000	1193.25	0.21	251
500000	1397.55	0.2	265

And... there we are folks, hull stats in mass based form.  Assuming, of course, that 4 metric tons per Traveller displacement ton isn't too far out of line as a guesstimate of the total wet mass of a ship.

For the remainder of the design, volume is pretty much irrelevant. *happy dance*

Errata: I've discovered that I underestimated the number of mount points required once I started including radiators, engine thrust nozzles, etc along with weapons.  I believe the above numbers should at least be doubled, perhaps more.  Err make that x10, seems I forgot a few things!

Addition: It seems I do need a 'length' factor for a few things, most realistic combat hull configurations will fall within the figure given by the following formula within 25% or so, for others it doesn't really matter.  Lf = 1.25*(7*Mt)^(1/3).  It's a little more funky even than the other formulas but it should serve the purpose.

Simple Complexity.. or is it Complex Simplicity..

Hard science fiction spacecraft design seems to necessitate complexity, but is that true?  There is no doubt that some complexity is needed in order to reflect real world engineering limitations and physics, but does that mean the entire design sequence must therefore be complex?  I think not.

The target here is a design process somewhere between CT Bk2 and CT Bk5 in simplicity but with the addition of a few items specific to the setting, inclusion of a few popular items, and removal of anything not supported by the setting.

Hull section replaced by:

Hulls - Take 2 - Mass Effect?

Hull
A Dark Stars hull specification has a size in displacement tons, an atmospheric rating, and a structural rating.  The first is simply the overall size of the spacecraft in familiar Traveller (CT) displacement tons.  The atmospheric rating is a combination of overall shape and atmospheric performance.  The structural rating is a combination of armor value, maximum acceleration rating, and agility rating (basically rate of turning).

Unfortunately realistic hull designs require a fair bit of math.  A table of common hull sizes is provided to alleviate this in most cases.

Code	Atmospheric rating	Hull cost modifier	Waste hull volume percentage
0	Non-atmospheric	1.0	0
1	Partial streamlining	1.1	2
2	Streamlined	1.2	5
3	Lifting body	1.5	10

The structural factor of a spacecraft is given by the following formula:Sf =  (Td/1000)^(3/2); the square root of the cube of Td divided by 1000.
The structural rating is then given by:
Sr = Sf * Gq * Aq * 0.25 ; where Gq is the hull G rating in quarter G's, and Aq is the structure Agility rating in quarter G's.  Minimum values for Gq and Aq are 1.
The minimum structural rating is 1.

The minimum armor value is 1 (corresponds to Striker AV32; AV2 would be AV40 or High Guard 0).
Armor volume correction = 10 / Td^(1/3); ten divided by the cube root of Td.
The armor material rating is the armor value multiplied by the armor volume correction factor.
The maximum armor value is equivalent to the tech level of hull construction.
The minimum armor material rating is 1.

The material volume required is given by multiplying the sum of the armor material rating and the structural rating by the material volume tech level modifier.

TL	Percent of craft per material rating
7-9	2.0
10-11	1.5
12-13	1.0
14-15	0.5

Hull cost is MCr 1.0 per Td of hull material multiplied by the hull cost modifier.

Maximum number of hardpoints =0.75 * Td^(1/2); three quarters of the square root of Td.
Turrets and fixed weapon mounts require one hardpoint each; 50 Td bays require three hardpoints each; 100 Td bays require five hardpoints each.


The following table gives structural factors, armor volume multipliers, and maximum hardpoints for a variety of common hull sizes.

Hull size	Sf	AVM	Max Hardpoints
10	0.01	4.65	2
15	0.01	4.06	2
20	0.01	3.69	3
25	0.01	3.42	3
30	0.01	3.22	4
35	0.01	3.06	4
40	0.01	2.93	4
45	0.01	2.82	5
50	0.02	2.72	5
55	0.02	2.63	5
60	0.02	2.56	5
65	0.02	2.49	6
70	0.02	2.43	6
75	0.03	2.38	6
80	0.03	2.33	6
85	0.03	2.28	6
90	0.03	2.24	7
95	0.03	2.2	7
100	0.04	2.16	7
150	0.06	1.89	9
200	0.09	1.71	10
250	0.13	1.59	11
300	0.17	1.5	12
350	0.21	1.42	14
400	0.26	1.36	15
450	0.31	1.31	15
500	0.36	1.26	16
600	0.47	1.19	18
700	0.59	1.13	19
800	0.72	1.08	21
900	0.86	1.04	22
1000	1	1	23
1100	1.16	0.97	24
1200	1.32	0.95	25
1300	1.49	0.92	27
1400	1.66	0.9	28
1500	1.84	0.88	29
1600	2.03	0.86	30
1700	2.22	0.84	30
1800	2.42	0.83	31
1900	2.62	0.81	32
2000	2.83	0.8	33
2100	3.05	0.79	34
2200	3.27	0.77	35
2300	3.49	0.76	35
2400	3.72	0.75	36
2500	3.96	0.74	37
2600	4.2	0.73	38
2700	4.44	0.72	38
2800	4.69	0.71	39
2900	4.94	0.71	40
3000	5.2	0.7	41
3100	5.46	0.69	41
3200	5.73	0.68	42
3300	6	0.68	43
3400	6.27	0.67	43
3500	6.55	0.66	44
3600	6.84	0.66	45
3700	7.12	0.65	45
3800	7.41	0.65	46
3900	7.71	0.64	46
4000	8	0.63	47
4100	8.31	0.63	48
4200	8.61	0.62	48
4300	8.92	0.62	49
4400	9.23	0.62	49
4500	9.55	0.61	50
4600	9.87	0.61	50
4700	10.19	0.6	51
4800	10.52	0.6	51
4900	10.85	0.59	52
5000	11.19	0.59	53
5100	11.52	0.59	53
5200	11.86	0.58	54
5300	12.21	0.58	54
5400	12.55	0.57	55
5500	12.9	0.57	55
5600	13.26	0.57	56
5700	13.61	0.56	56
5800	13.97	0.56	57
5900	14.34	0.56	57
6000	14.7	0.56	58
6100	15.07	0.55	58
6200	15.44	0.55	59
6300	15.82	0.55	59
6400	16.2	0.54	60
6500	16.58	0.54	60
6600	16.96	0.54	60
6700	17.35	0.54	61
6800	17.74	0.53	61
6900	18.13	0.53	62
7000	18.53	0.53	62
7100	18.92	0.53	63
7200	19.32	0.52	63
7300	19.73	0.52	64
7400	20.14	0.52	64
7500	20.54	0.52	64
7600	20.96	0.51	65
7700	21.37	0.51	65
7800	21.79	0.51	66
7900	22.21	0.51	66
8000	22.63	0.5	67
8100	23.06	0.5	67
8200	23.49	0.5	67
8300	23.92	0.5	68
8400	24.35	0.5	68
8500	24.79	0.49	69
8600	25.23	0.49	69
8700	25.67	0.49	69
8800	26.11	0.49	70
8900	26.56	0.49	70
9000	27	0.49	71
9100	27.46	0.48	71
9200	27.91	0.48	71
9300	28.37	0.48	72
9400	28.82	0.48	72
9500	29.29	0.48	73
9600	29.75	0.48	73
9700	30.22	0.47	73
9800	30.68	0.47	74
9900	31.15	0.47	74
10000	31.63	0.47	75

A couple of notes:
The maximum hardpoint figure is based on estimated surface area with a break even (to normal rules) at 5600Td.
Under 1000Td armor requires more volume for a given value, this reflects the non-linear surface area vs volume relationship.
The 1000Td figure is also the breakpoint for structural volumes, high G-rated, high Agility value large hulls require extensive structural support.

This is still a work in progress but I believe it is a good starting point.
Till next time,
Omnivore out