General Chameleon Hulls

[Redcap]

In MGT2E, there is provision to install a holographic projector set into the hull of a starship, so as to be able to effectively redecorate the hull colours at will; this can be used commercially, to change a ships colours (example: A ship is bought by a new company, and it has to be refitted to match the company's colours), and militarily (camouflage on a planet, deep black in space, and so on).

However, while chameleon hull were mentioned in MT (Starship Operators Manual, a DGP publication, DGP-872-0895), there is no mention of these systems, or how to incorporate them into a new design, let alone add them to an existing design, in the Referee's manual, the Consolidated Eratta for MT, or, that I can find, in any of the JTAS/Challenge/Traveller's Digest/MegaTraveller Journals.

Does anyone have a House Rule for this within the MT rules set, please?

Thanks in advance

 

[Redcap]

Let's put this one to bed; got an answer from elsewhere; MgT2 HG and HGU2022 both state the same thing, regarding the incorporation of a chameleon skin to a hull under construction; it costs Cr100,000 per ton of hull, and requires 1 point of energy for every 2 tons of hull.

Since these do not consume measurable volume or mass, there is no tonnage cost.So, a retrofit for this MgT2E OTR back to MT is on the cards

Nice when it's a easy fix

 

[Commander Truestar]

While playing MT(with house rules) IMTU, I have firmly told my players any craft must be "built with" a Chameleon Hull because retrofitting the craft would require ripping off the existing hull to replace it with a new-built hull. And, that could cost a HUGe amount of Cr

 

[BackworldTraveller]

Given that a holographic projector is very cheap and easily fitted into clothing as a clothing computer, the cost per dTon seems excessive for a colour-painter.

A 100 dTon ship is spending Cr16,000 per square metre of surface area for the technology. How much is a flat-screen telly with the same size?...which would do the job just as well. Cr5000 per dTon may be more realistic!

 

[Grav_Moped]

Given that a holographic projector is very cheap and easily fitted into clothing as a clothing computer, the cost per dTon seems excessive for a colour-painter.

A 100 dTon ship is spending Cr16,000 per square metre of surface area for the technology. How much is a flat-screen telly with the same size?...which would do the job just as well. Cr5000 per dTon may be more realistic!

The ship-version likely to be projecting over far more than the visual-light spectrum, where a personal unit is just doing visible light (give or take human/alien variations of what constitutes "visible").

 

[kilemall]

The ship-version likely to be projecting over far more than the visual-light spectrum, where a personal unit is just doing visible light (give or take human/alien variations of what constitutes "visible").

Well that is a nice lead in for describing my stealth system.

The basic cost is 10% of the cost of the whole ship per +1 stealth DM- for the EM band covered. Since I have something like 11 including acoustics, visual, IR, UV, radar, etc. and it takes at least +3/4 to be effective, we are talking 4-5x the cost of the ship to get stealthier.

This is because all systems have to be built and operate to disguise emissions or reflections. Also means the ship costs the same multiplier to repair to full stealth spec, and maintenance costs that much more.

So two strategies to mitigate. Since ships in IMTU are limited by their computer models for long range EM bands, you can optimize for common sensor combinations, or at least ones you know your opponents use.

Of course that means that odd surprise ships like say a science ship may have EM detection you aren’t covering.

The more common choice is to only stealth small craft. For most purposes like recon, surprise attack of light opposition, specops, smuggling etc. a small craft will do and is far easier on the budget.

 

[mike wightman]

So what happens to all the waste heat?

 

[Grav_Moped]

So what happens to all the waste heat?

It gets used to make the drives violate the first law of thermodynamics.

 

[kilemall]

So what happens to all the waste heat?

Pick your technobabble.

Gravitic coolers.

Thermogenic mass converters.

Hydrogen concentrator exhaust.

 

[Spinward Flow]

So what happens to all the waste heat?

Ever heard of a Refrigeration Laser?
The "wolfling" humans used one in a unique craft they built for exploring the photosphere and atmosphere of their own star at EXTREMELY CLOSE RANGE.

Works a lot like a "bilge pump" (conceptually speaking) ... except that instead of dumping "waste water" that accumulates inside the hull overboard, you're dumping "waste heat" that accumulates inside the hull overboard.

The engineering is basically a heat pump refrigeration cycle that concentrates the (waste) heat "exhaust" into the output of a laser which then gets pointed away from the craft, dumping the waste heat overboard out into space. The dual purpose engineering genius in the building of the Sundiver was that the refrigeration function was basically piggy backed onto the "millions of degrees" communication laser the craft needed to be able to maintain laser communications with outside assets during sundives into the atmosphere, so as to be able to use an EM band that wouldn't be overwhelmed and jammed by Sol's (incredibly noisy) radiation output while the sundiver ship was conducting research.

Same basic concept as how a refrigerator works in your kitchen (take excess heat from inside, dump it outside) but done in a very different application. The physics are the same, but the engineering is different.

Credit to David Brin for writing the book.

 

[mike wightman]

The concept breaks the laws of thermodynamics - put another way it won't work.

I note the words refrigeration cycle - which must be powered and therefore generates more waste heat
laser - at best 20% efficient in Traveller so 80% yet more waste heat.

So you generate a lot more waste heat trying to get rid of the waste heat.

 

[Spinward Flow]

So you generate a lot more waste heat trying to get rid of the waste heat.

Ever heard of a heat pump?

The heat pump was invented in 1850 (TL=4!).
Use 50 watts to shunt 200+ watts of heat energy elsewhere (even at TL=7!).
Real world technology TODAY can achieve 300-400% efficiency using modern heat pumps.

Heat pumps today can reach 300% to 400% efficiency or even higher, meaning they're putting out three to four times as much energy in the form of heat as they're using in electricity.

How does a heat pump work?
At a high level, a heat pump gathers heat from one place and puts it in another place.

Try to imagine what heat pumps can do at TL=9+ ...

And just in case you missed the reference ...

The engineering is basically a heat pump refrigeration cycle that concentrates the (waste) heat "exhaust" into the output of a laser which then gets pointed away from the craft, dumping the waste heat overboard out into space.

---

The concept breaks the laws of thermodynamics - put another way it won't work.

Care to revise and extend your remarks/opinion?

 

[mike wightman]

Buried within your reply you should be able to spot the problem.
No energy transfer can be above 100% efficient. I certainly wouldn't be using an advert for "heat pump home heating solutions" to try to score points.

 

[mike wightman]

You state 200+ watts of waste heat - which by definition can not do useful work
You then spend another 50W of useful work to "move the waste heat" - which generates more waste heat.

So whatever you are doing your power systems are generating (x) amount of watts of which (x)-200 watts are useful work and 200 watts ends up as waste heat.

Let's assume that (x) watts includes the heat pump the waste heat can not be used to power a laser.

Actually that is not strictly true - you could have a temperature gradient set up to generate electricity, but guess what. You need something colder than your heat sink and you generate more waste heat doing this.

There are only two ways to get rid of waste heat - transfer it to a radiator or dump the hot stuff.

 

[Grav_Moped]

Oh, and no energy transfer can be above 100% efficient.

This is why all the waste heat goes into the subsystem that enables breaking the First Law of Thermodynamics.

(Don't ask how that part of it works. It just does, okay?)

 

[mike wightman]

I hand wave gravitic heat sinks... the waste heat somehow ends up as artificial gravity and acceleration compensation

 

[Baroun Tardis]

The thought crosses my mind..
Hydrogen becomes liquid at around 20K
If our fuel processor brings it down to, say, 10K then it'll stay liquid until it hits 20K
Also, as pressure increases, the boiling point rises.

LHyd has a spefic heat of around 10 J/(g K)
At -252.87°C and 1.013 bar, liquid hydrogen has a density of close to 71 kg/m3

That's about 680Mj of heat per d-ton of fuel before it boils, and if the fuel tanks can maintain higher pressures, that even more juice.

The numbers for energy production per cubic meter of LHyd in MT show the fusion reactors as incredibly inefficent fuel guzzlers...
What if most of that fuel consumption is actually coolant being vented off?
You could have a heat exchanger system where it sucks in fuel from the tank, keeps it under very high pressure to keep sucking up heat, then vents it off carrying heat away from the ship. There could even be some kind of Maxwell's Demon to only vent off the hottest molecules.

 

[kilemall]

The thought crosses my mind..
Hydrogen becomes liquid at around 20K
If our fuel processor brings it down to, say, 10K then it'll stay liquid until it hits 20K
Also, as pressure increases, the boiling point rises.

LHyd has a spefic heat of around 10 J/(g K)
At -252.87°C and 1.013 bar, liquid hydrogen has a density of close to 71 kg/m3

That's about 680Mj of heat per d-ton of fuel before it boils, and if the fuel tanks can maintain higher pressures, that even more juice.

The numbers for energy production per cubic meter of LHyd in MT show the fusion reactors as incredibly inefficent fuel guzzlers...
What if most of that fuel consumption is actually coolant being vented off?
You could have a heat exchanger system where it sucks in fuel from the tank, keeps it under very high pressure to keep sucking up heat, then vents it off carrying heat away from the ship. There could even be some kind of Maxwell's Demon to only vent off the hottest molecules.

That’s my assumption, why 4 week amount independent of travel distances, and that letter drive plants are less efficient cooling and thus burn through more.

 

[Spinward Flow]

No energy transfer can be above 100% efficient.

Point.
Click.
LEARN.

No need to take MY word for it ...

 

[Grav_Moped]

Point.
Click.
LEARN.

No need to take MY word for it ...

It's the difference between open and closed systems.

A heat pump may be quite efficient at extracting heat from one side and moving it to the other side. The total energy in the hot/cold/exterior system as a whole, increases though -- as a minimum, by whatever energy is used to run the equipment.

Doesn't matter how efficient your refrigerator is, it ain't gonna cool your house when you leave the door open.

The best that can plausibly be managed is to collect all the radiated heat and send it in a narrow beam in a direction that you hope doesn't have any observers. And even that has limits.