Now that we have our solar system more or less laid out, let's continue looking into the economy. Broadly speaking, the economy exists to transform time into spaceships with which to blast the enemy. Consequently, in broad strokes let's try and figure out what goes into spaceships.
There are only a few really vital characteristics to a warship. From my previous post, the interesting ones are:
How hard it hits
How many hits it can take
How accurately it fires
How fast it can move
How much it can carry
The question here is, how do you achieve those characteristics, and what materials do you need so to do?
How hard it hits:
Nuclear weapons. Your standard atom bomb has a hollow sphere of plutonium in the middle, surrounded by a soccer ball array of high explosives, which have some complicated electronic triggering mechanism. Then you stick it in a steel shell so it doesn't fall apart, and a rocket engine on the back to get it where you want it to go. (the bomb detonates by blowing the high explosives to crush the plutonium into a very small nugget, which then hits critical mass. It's bombarded by neutrons, and all hell breaks loose.)
So, in a materials checklist we have: Plutonium, High Explosives, Advanced Electronics, Steel, and a Rocket Engine.
What's in a rocket engine? Let's skip down to
How fast it can move
I'm thinking of these ships moving due to advanced fusion motors. What makes them advanced? My say so. Also, if you install a Langston Field into a heat engine you can get some interesting properties. If you stop over once again at the incontestably useful Project Rho, you learn that one of the main factors that affects the feasibility of engines is not letting your engine melt due to waste heat. If we run our fusion reactions inside an inverted Langston field, the energy from the reaction is absorbed and emitted only inwards; we can sustain all kinds of scary high energy reactions without damaging our ship or crew. Just leave a hole open in the back so that you can go rocketing along. (I haven't run the numbers proper just yet, but I expect I'll work off of this type of engine)
Anyways, an engine includes Fuel, Reaction Mass and a Langston Field generator. Since I mentioned the ability for spaceships to generate their own hydrogen supplies (again with that field. You see why I try to keep my miracle devices to a minimum?), I think we'll qualify both fuel and reaction mass as Hydrogen, allowing us to move on to
How many hits it can take
Which is entirely dependent on the properties of a Langston Field generator. So I guess I've got to 'fess up to what's actually in these things. You ready?
Exotic Materials.
No, I don't have any idea how one of those things ought to work either. Moving along;
How accurately it fires
Since we're pretty much entirely talking about missiles, we're asking what a missile needs to connect with it's target. It needs to find a potential target, identify as friend or foe, measure relative positions, velocities and accelerations and modify it's own vectors to collide with said target. It also needs something to tell it precisely when to detonate.
All that I'm going to sum up in my previous category of Advanced Electronics. Convenient. One last warship category:
How much it can carry
Seeing as cargo space is mostly empty volume, we can ignore this category. Or, in a move that saves me some rewriting on this post, we can talk about what the ship needs to carry some of it's more vital components; people.
People require some basic things to live. Food, water, air, access to the internet. At least those first three. In the context of our discussion, our spaceships have to be able to carry a basic livable habitat for the people. In resource terms, I'm going to shoehorn all of that into Organics; I'm looking to build game pieces not actual starships. Note though, that a troop transport ship will require a whole lot more life support than an ore freighter.
There are also considerations involving the ship itself; you need a steel framework to hold the various pieces together (you could go with titanium or some such, but with the Langston field providing the defense, you really only need enough structure to hold the thing together. Steel is still cheapest.) You need some vast, complicated bridge with a huge glass window and oddly shaped chairs and large computer banks with blinking lights on them. There are other features that are useful for maintenance, Medbays, Machine shops, the sergeant's illicit still, that sort of stuff. But broadly speaking, they fall under the same resource categories. To sum up:
Organics, Steel, Advanced Electronics
Let's list out those resource types for all the categories:
Plutonium
High Explosives
Advanced Electronics
Steel
Hydrogen
Exotic Materials
Organics
Seven types of resource. Can we pare that list down at all? Sure. For starters, let's just pretend the High Explosives don't exist. (Side note: this is not a winning legal defense.) Furthermore, Plutonium is only a component on the bomb side of things. If we upgrade to H-bombs, we still need a plutonium detonation to trigger the hydrogen explosion. I suppose I could just say "Future!" and hand wave that away. I think I'd rather shoehorn it into the Exotics category. One more; Hydrogen, while it's useful to remember it's there, can be safely ignored. That brings us down to four categories:
Electronics
Metals
Organics
Exotics
I'm going to add in one more category:
Labor
Or possibly Money. I'm less certain about this one than the others. While I don't want to get into all the details of financing (buy war bonds!) I want to provide a resource that can be expended to ease tension between other resource amounts. So, if you don't have enough Electronics one week you can expend a certain amount of Metals and Labor to turn it into Electronics. Or if you need more steel, you can expend labor to boost it up wholesale from Earth's gravity well. (Remember, the cheapest way to get steel in space is to start with steel that's already up there; thus the asteroid mining and so forth. You can stick some on a Saturn V rocket and send it up to the orbital factories, but that'll cost you.)
It also allows us to gather resources from locations that wouldn't have them normally, or produce the wrong type. There's a small settlement on Mars; not large enough to pull things out of the gravity well. So what good is it? It produces Labor.
As with most things at this stage of the game, these resources aren't set in stone. Except for the metals, which are probably an ore in some obscure asteroid right now. Next time I get back to this topic We'll go over a map of the solar system and discuss what gets produced where, and how much.
Showing posts with label Langston Field. Show all posts
Showing posts with label Langston Field. Show all posts
Sunday, July 31, 2011
Monday, May 17, 2010
The Langston Field and Thermodynamics
Here I'm analyzing some further implications of the Langston Field. We're going to get into some thermodynamics and what that implies for spaceships and weapons in the Terrible Secret of Space.
I stated in the last post that the field radiates like a black body. The question is, what exactly does that mean? Black body radiation describes the way that stuff gives off light depending on how hot it is. The interesting thing about black body radiation is that it doesn't depend on what size, or shape, or color, or even if the object in question is a communist. It only depends on the temperature. An incandescent light bulb shines because that filament is really, really hot. You're emitting infra-red radiation right now, you can't tell because you eyes don't see at that wavelength. The SWAT team that just cut your power and battered down your door can see them, though. Their heat vision goggles sense the heat you're emitting, and can tell by the wavelength the difference between you (100 degrees) and your nightstand (70 degrees.)
So we said that the shields shift up the color spectrum as they take damage, taking in heat and emitting it like a black body. But since black body's don't care what's doing the emitting, we can figure out how hot the shield is. Let's say the ship blows up when it's emitting light at a wavelength of about 400 nanometers. That's in the deep purple region of colors. Just before it overloads, the shield is going to hit a temperature of about 7250 kelvin. That's plenty enough to melt and boil tungsten or what have you. There are some problems raised by that; how do you see out of one of these shields? I mean, it's black. It stops light. There's no way to get it to stop "dangerous" light like lasers but not "useful" light like, oh, the stuff that shows you where your opponent is. You could build cameras on metal poles and stick them through the shields (the shields will allow matter to pass, and electric signals should be able to get through). And then someone actually shoots you enough, your cameras melt off and you're blind again. Well before the explosion point.
I'm thinking the answer to that is that you can open holes in your own shield. This is suboptimal in combat because someone might try to shoot through your holes, but necessary. I mean, you've got to shoot your laser cannons out, right? Blasting it into your own shield seems counterproductive. Also, your fusion drive has to shoot materials out the back, if they get caught in the shield you won't go anywhere.
That's not the biggest problem, though. Remember how black bodies radiate solely based on their temperature? Exactly how much do they radiate? There's an equation for that (I won't post it, partly because you can't be bothered with it and partly because I can't be bothered with getting the Greek symbols and formatting equations in a text file). The amount of energy emitted is proportional to the fourth power of the temperature. Not just squared or cubed, raised to the fourth power. What's 7250 to the fourth? Roughly 2.7 quadrillion (thanks Windows Calculator!). Quadrillion, as in even the federal deficit hasn't gotten that large yet. The proportion factors are all pretty small decimals, but we end up with a huge number nonetheless. Let's say a spaceship has a spherical shield with a 100 meter radius. Now heat that ship up to the explosion point. Just before it's exploding that ship will be emitting a kiloton of energy in black body radiation every second.
A kiloton of energy every second. Remember Hiroshima? In one minute a spaceship like that could duplicate the effects.
Now let's go over the disturbing implications of that. And not just it's uses as a superweapon. (If you're gonna do that, why not just lob the atom bombs and cut out the middle man?) If the spaceship is radiating kilotons of energy, how much energy do you have to put in to keep pushing the shield temperature up? At some point you're lobbing atom bombs at it to make sure the damn thing doesn't cool down on you, let alone cook off. You can probably do it with H bombs, but your laser batteries might fall short. Weapons are going to have to be culled because we're gonna have to ask ourselves "neat as this is, is it really as destructive as an atom bomb?". Naturally this saddens me.
Now, if you're emitting that much energy, how close do I want to fly to you? Forget the explosion (for the moment) My shields will be heating up just going by. Probably not going to be a major concern for another ship. But let's say we're having a battle in orbit over the planet. You detonate enough atom bombs directly above the atmosphere and you'll pump in enough heat to affect the weather. I haven't done any calculations about this, but you might start fires or kill crops or some such.
For that matter, what about using a shield as a weapon? If you take a starship, nuke it profusely and then send it hurtling through someone's atmosphere, set so that the final collision will overload the shield you can create an explosion that makes your garden variety atomic bomb weep. You've got all the energy of those nukes plus the energy of a giant freaking meteor hitting stored in the shield. You could raze continents with those. Y'know, as if you couldn't with enough nukes already.
(There are also conservation of momentum problems here that I didn't consider. Particle hits shield makes sense. Shield hits planet makes less sense. Does it slow the planet enough to overload the shield? For collisions of any velocity?)
That brings up another question. How much energy exactly can one of these shields absorb? I'm gonna have to talk about Specific Heat here, and how it's totally inapplicable to the problem at hand but I'm going to use it nonetheless. Specific heat is a measure of how much energy something can hold. For a given mass, different materials will hold different amounts of heat. An experiment! Take a mass of iron, boil it in water. Take an equal mass of water. Dump them both out on a snowbank, and see which one melts more snow. You'll get more melting from the water because even though they're undergoing the same change in temperature the water can hold more heat than the iron. It has a higher specific heat.
Now drop an atom bomb on that snowbank. The snow will melt and vaporize. So will that chunk of iron. And anything else in the nearby area. You could build a chunk of iron large enough to not melt when you hit it with a nuke, but it'd take a lot of iron. (At least you could build one if the heat conducted at an infinite rate; as it stands the nuke is still going to leave a crater.) The question is, what specific heat do those fancy schmancy Langston fields have, what with the not cooking off with the first nuke that comes their way? Well, it's hard to say. Y'see, the shields are force field, and they don't exactly have a mass. (Ok, all energy has a mass, thanks Mr. Einstein, but I can't wrap my head around asking about the specific heat of a quantity of heat. The question makes even less sense than my twisted diction.) Specific heat depends on having a mass. So the question doesn't even apply.
But, as I stated earlier, I'm not going to let that stand in the way of Science! We can work out a volume for these shields (say a 3 meter shell on a 97 meter warship to get that 100 meter shield I was talking about). We can throw in a "density" factor so that we can work out an effective mass, and from there we can figure out exactly what sort of heat capacity the shields have to have. If some practical joker took away your Langston field and substituted water for it, it'd have a known density (1) and heat capacity (4 point something). We could calculate how much energy the water would absorb before it'd heat to the requisite 7250 kelvin. Assuming, of course, the wildly unphysical notion that the water would stick around to be heated and not boil off the very first chance it gets. But the heat, the heat could be provided by a single atom bomb, blasting through your shields and wrecking your ship.
This will not do. Fortunately, our shields aren't made out of water, but are pulled form the figurative aether. By fiddling with the heat capacity factor we can work out a shield that will not only survive the first nuke but several more, changing into pretty colors and radiating energy and doing all the other wonderful things I'm counting on the Langston field to do. Roughly, I expect this handwaved heat capacity to be a hundred million times larger than that of water.
I doubt this is the last I have to say about Langston fields. But it's good enough for now.
I stated in the last post that the field radiates like a black body. The question is, what exactly does that mean? Black body radiation describes the way that stuff gives off light depending on how hot it is. The interesting thing about black body radiation is that it doesn't depend on what size, or shape, or color, or even if the object in question is a communist. It only depends on the temperature. An incandescent light bulb shines because that filament is really, really hot. You're emitting infra-red radiation right now, you can't tell because you eyes don't see at that wavelength. The SWAT team that just cut your power and battered down your door can see them, though. Their heat vision goggles sense the heat you're emitting, and can tell by the wavelength the difference between you (100 degrees) and your nightstand (70 degrees.)
So we said that the shields shift up the color spectrum as they take damage, taking in heat and emitting it like a black body. But since black body's don't care what's doing the emitting, we can figure out how hot the shield is. Let's say the ship blows up when it's emitting light at a wavelength of about 400 nanometers. That's in the deep purple region of colors. Just before it overloads, the shield is going to hit a temperature of about 7250 kelvin. That's plenty enough to melt and boil tungsten or what have you. There are some problems raised by that; how do you see out of one of these shields? I mean, it's black. It stops light. There's no way to get it to stop "dangerous" light like lasers but not "useful" light like, oh, the stuff that shows you where your opponent is. You could build cameras on metal poles and stick them through the shields (the shields will allow matter to pass, and electric signals should be able to get through). And then someone actually shoots you enough, your cameras melt off and you're blind again. Well before the explosion point.
I'm thinking the answer to that is that you can open holes in your own shield. This is suboptimal in combat because someone might try to shoot through your holes, but necessary. I mean, you've got to shoot your laser cannons out, right? Blasting it into your own shield seems counterproductive. Also, your fusion drive has to shoot materials out the back, if they get caught in the shield you won't go anywhere.
That's not the biggest problem, though. Remember how black bodies radiate solely based on their temperature? Exactly how much do they radiate? There's an equation for that (I won't post it, partly because you can't be bothered with it and partly because I can't be bothered with getting the Greek symbols and formatting equations in a text file). The amount of energy emitted is proportional to the fourth power of the temperature. Not just squared or cubed, raised to the fourth power. What's 7250 to the fourth? Roughly 2.7 quadrillion (thanks Windows Calculator!). Quadrillion, as in even the federal deficit hasn't gotten that large yet. The proportion factors are all pretty small decimals, but we end up with a huge number nonetheless. Let's say a spaceship has a spherical shield with a 100 meter radius. Now heat that ship up to the explosion point. Just before it's exploding that ship will be emitting a kiloton of energy in black body radiation every second.
A kiloton of energy every second. Remember Hiroshima? In one minute a spaceship like that could duplicate the effects.
Now let's go over the disturbing implications of that. And not just it's uses as a superweapon. (If you're gonna do that, why not just lob the atom bombs and cut out the middle man?) If the spaceship is radiating kilotons of energy, how much energy do you have to put in to keep pushing the shield temperature up? At some point you're lobbing atom bombs at it to make sure the damn thing doesn't cool down on you, let alone cook off. You can probably do it with H bombs, but your laser batteries might fall short. Weapons are going to have to be culled because we're gonna have to ask ourselves "neat as this is, is it really as destructive as an atom bomb?". Naturally this saddens me.
Now, if you're emitting that much energy, how close do I want to fly to you? Forget the explosion (for the moment) My shields will be heating up just going by. Probably not going to be a major concern for another ship. But let's say we're having a battle in orbit over the planet. You detonate enough atom bombs directly above the atmosphere and you'll pump in enough heat to affect the weather. I haven't done any calculations about this, but you might start fires or kill crops or some such.
For that matter, what about using a shield as a weapon? If you take a starship, nuke it profusely and then send it hurtling through someone's atmosphere, set so that the final collision will overload the shield you can create an explosion that makes your garden variety atomic bomb weep. You've got all the energy of those nukes plus the energy of a giant freaking meteor hitting stored in the shield. You could raze continents with those. Y'know, as if you couldn't with enough nukes already.
(There are also conservation of momentum problems here that I didn't consider. Particle hits shield makes sense. Shield hits planet makes less sense. Does it slow the planet enough to overload the shield? For collisions of any velocity?)
That brings up another question. How much energy exactly can one of these shields absorb? I'm gonna have to talk about Specific Heat here, and how it's totally inapplicable to the problem at hand but I'm going to use it nonetheless. Specific heat is a measure of how much energy something can hold. For a given mass, different materials will hold different amounts of heat. An experiment! Take a mass of iron, boil it in water. Take an equal mass of water. Dump them both out on a snowbank, and see which one melts more snow. You'll get more melting from the water because even though they're undergoing the same change in temperature the water can hold more heat than the iron. It has a higher specific heat.
Now drop an atom bomb on that snowbank. The snow will melt and vaporize. So will that chunk of iron. And anything else in the nearby area. You could build a chunk of iron large enough to not melt when you hit it with a nuke, but it'd take a lot of iron. (At least you could build one if the heat conducted at an infinite rate; as it stands the nuke is still going to leave a crater.) The question is, what specific heat do those fancy schmancy Langston fields have, what with the not cooking off with the first nuke that comes their way? Well, it's hard to say. Y'see, the shields are force field, and they don't exactly have a mass. (Ok, all energy has a mass, thanks Mr. Einstein, but I can't wrap my head around asking about the specific heat of a quantity of heat. The question makes even less sense than my twisted diction.) Specific heat depends on having a mass. So the question doesn't even apply.
But, as I stated earlier, I'm not going to let that stand in the way of Science! We can work out a volume for these shields (say a 3 meter shell on a 97 meter warship to get that 100 meter shield I was talking about). We can throw in a "density" factor so that we can work out an effective mass, and from there we can figure out exactly what sort of heat capacity the shields have to have. If some practical joker took away your Langston field and substituted water for it, it'd have a known density (1) and heat capacity (4 point something). We could calculate how much energy the water would absorb before it'd heat to the requisite 7250 kelvin. Assuming, of course, the wildly unphysical notion that the water would stick around to be heated and not boil off the very first chance it gets. But the heat, the heat could be provided by a single atom bomb, blasting through your shields and wrecking your ship.
This will not do. Fortunately, our shields aren't made out of water, but are pulled form the figurative aether. By fiddling with the heat capacity factor we can work out a shield that will not only survive the first nuke but several more, changing into pretty colors and radiating energy and doing all the other wonderful things I'm counting on the Langston field to do. Roughly, I expect this handwaved heat capacity to be a hundred million times larger than that of water.
I doubt this is the last I have to say about Langston fields. But it's good enough for now.
Wednesday, May 5, 2010
The Langston Field
Been a bit since I last advanced the Terrible Secret of Space. If you'll recall, last time I was working out some necessary consequences of having spaceships that travel around the solar system. Basically, if you can get a ship up to speed, it makes a great rock to hurl at those who would oppose you. Or those who might think of opposing you. Or those who might think of looking at you funny. Or... I'd better get off this train of thought.
Specifically, at the close of my last post I didn't have a satisfactory reason for why the evil invading aliens couldn't strap a drive on just any old rock and blast capital ships out of the sky or selectively target important military installations. After duly considering the problem, I've got the solution: Cheat!
I'm stealing the Langston Field from the novel The Mote in God's Eye by Larry Niven and Jerry Pournelle. The aforementioned field drains energy from objects in motion, including such extremely high energy objects as plasma from fusion torpedoes or photons from laser cannons. Importantly though, the book also works out the restrictions. The field has to absorb that energy, which it disposes of by radiating outwards as a black body. If it can't radiate the energy faster than it takes it in, the shield heats up until it overloads, destroying the ship inside.
This has all sorts of useful applications for a boardgame. For starters, it neatly allows us to sidestep the issue of throwing rocks at capital ships; the shields will be able to survive that sort of attack. Doubly so for ground installations. It also provides a handy way to track damage done to ships; in the book the shields remained black until enough energy is absorbed that it starts changing color, from red on up the rainbow. Makes a pretty convenient way to define and measure hit points.
So what do we actually know about the shields?
1) The shields absorb energy. They reradiate it like blackbody radiation. The specific heat of the shields must be proportionally huge, they can absorb large amounts of energy.
2) They absorb momentum proportional to the cube of the incoming velocity. Which means they absorb a lot more energy from, say, an incoming particle beam than from an object moving at slow speeds.
3) They're generally spherical in shape. This probably works to our advantage otherwise, seeing as a sphere is best for radiating away excess energy.
4) Small holes can be punched through the shield. This allows useful things like laser batteries or the fusion reaction to get out.
5) Some energy gets through; there's a lot of talk in the book about how the ships get shaken about in major fleet actions, and about necessary repairs.
6) The shields dampen all motion. If you get stuck in one, it'll dampen the beating of your heart etc.
7) Absorbing energy is really useful if you want an ultra efficient sci-fi star drive. Say, the sort of thing that could stand .1g over extended periods of time. Not sure that I'm going to get into a detailed explanation of how the engines work, but it's nice to remember.
8) Shields have some thickness. They take up a volume of space. They are fields though, so they don't exclude matter from taking up the same space.
9) Until a shield overloads, it mostly radiates it's energy outward. I don't know why this is. Probably storytelling necessity. Possibly I'm screwing up my physics.
10) Not stated but implied by the logic, ground based shields will be more efficient than space based ones; they can lose energy by conduction with the ground rather than just radiation.
11) When a shield overloads the energy will The overloaded Langston field is enough to vaporize whatever steel bulkheads you've got inside it. Only about half of the energy will be going inwards (I'm assuming it's proportional to surface area), the other half will be expanding out. While it'll be a lot more diffuse, I wouldn't want to be too close to an exploding ship for fear of overloading my own shields.
After a perusal of the book, I've still got a couple questions. What happens if two shields interact?
Let's say you put one inside another. That way, if your first shield blows, you've got another ready and waiting. Trouble is, when a shield blows it'll release a lot of energy. If the amount of energy a shield can store is proportional to the volume of space it occupies then the outer shield will by necessity be able to hold more energy. Consequently, when it releases all that energy it might overload the shield on the inside in just that one action. You could design around this though; by engineering your inside shield to have at least 51% of the energy capacity of your outer shield. Even if it only buys you a couple seconds, well, a couple seconds are valuable. We could assume as a principle of the physics that you can't have one shield inside another. Only that spells doom for making the drive ultraefficient.
Or what happens if you throw one field at another? Let's say you built Langston Fields into your torpedoes to make them harder to shoot down mid flight. When you launched it at another ship, what would happen? Well, let's say the fields cancel each other. Then you'd have an effective way to toss a torpedo through a field barrier, which makes the Langston field much less useful. Ok, what if the fields simply ignore each other. Then the torpedo would crash into the other ship's field, and work like described. Unless the torpedo would have a larger field, in which case it'd appear that the ship crashed into the torpedo's field, causing massive damage to the ship without injuring the torpedo. Also not optimal.
Let's see. The shields act to absorb incoming velocities. But you can impart a velocity to a shield by moving the generator on the inside. The shields are a projection of energy, but they also block energy. So if we assume that two shields would attempt to block each other out if they collided, then the two of them would have to absorb energy equal to the collective momentum of the system. Except that would leave them both at rest, and there's no reference frame to tell us what "at rest" means in that context. I could cheat by using the board to define a reference frame, but I'd rather not. One of the things I'm trying to do with this game is to not mess up the physics unless I absolutely have to. I can think of ways to explain the interaction of two shields, but none where the math will check out when two ships collide, and therefore none that I'd be happy using.
Ok, so suppose that it works that way. Well, possibly that I'll have to use a vector based movement system to describe how pieces move about the board. Honestly though, that'd probably happen anyway. Anything else? That it'll be possible to ram ships with other ships, for whatever purpose. Why would someone do that? Well, if you just hit them with a fusion torpedo their shield heats up. But if you sent in a spaceship on automatic you might be able to change their motion, say nudging them out of orbit or into the path of an asteroid or something.
Well, that's all the physics. Well, not all. I haven't touched on the thermodynamics much at all. Before I finish though, I'm going to add a couple restrictions to Langston Field Generators. Either they're really expensive to build, or they won't cover very small areas, or both. I'm saying this to limit the unintended consequences. If you could make cheap, small field generators then you could do all sorts of things with them. Really top notch fireproofing is probably the most boring. To limit the spread of miracle gadgets that do X, Y, or Z and implies T, U, and V, I think I'm going to limit these to small star ships and up.
Specifically, at the close of my last post I didn't have a satisfactory reason for why the evil invading aliens couldn't strap a drive on just any old rock and blast capital ships out of the sky or selectively target important military installations. After duly considering the problem, I've got the solution: Cheat!
I'm stealing the Langston Field from the novel The Mote in God's Eye by Larry Niven and Jerry Pournelle. The aforementioned field drains energy from objects in motion, including such extremely high energy objects as plasma from fusion torpedoes or photons from laser cannons. Importantly though, the book also works out the restrictions. The field has to absorb that energy, which it disposes of by radiating outwards as a black body. If it can't radiate the energy faster than it takes it in, the shield heats up until it overloads, destroying the ship inside.
This has all sorts of useful applications for a boardgame. For starters, it neatly allows us to sidestep the issue of throwing rocks at capital ships; the shields will be able to survive that sort of attack. Doubly so for ground installations. It also provides a handy way to track damage done to ships; in the book the shields remained black until enough energy is absorbed that it starts changing color, from red on up the rainbow. Makes a pretty convenient way to define and measure hit points.
So what do we actually know about the shields?
1) The shields absorb energy. They reradiate it like blackbody radiation. The specific heat of the shields must be proportionally huge, they can absorb large amounts of energy.
2) They absorb momentum proportional to the cube of the incoming velocity. Which means they absorb a lot more energy from, say, an incoming particle beam than from an object moving at slow speeds.
3) They're generally spherical in shape. This probably works to our advantage otherwise, seeing as a sphere is best for radiating away excess energy.
4) Small holes can be punched through the shield. This allows useful things like laser batteries or the fusion reaction to get out.
5) Some energy gets through; there's a lot of talk in the book about how the ships get shaken about in major fleet actions, and about necessary repairs.
6) The shields dampen all motion. If you get stuck in one, it'll dampen the beating of your heart etc.
7) Absorbing energy is really useful if you want an ultra efficient sci-fi star drive. Say, the sort of thing that could stand .1g over extended periods of time. Not sure that I'm going to get into a detailed explanation of how the engines work, but it's nice to remember.
8) Shields have some thickness. They take up a volume of space. They are fields though, so they don't exclude matter from taking up the same space.
9) Until a shield overloads, it mostly radiates it's energy outward. I don't know why this is. Probably storytelling necessity. Possibly I'm screwing up my physics.
10) Not stated but implied by the logic, ground based shields will be more efficient than space based ones; they can lose energy by conduction with the ground rather than just radiation.
11) When a shield overloads the energy will The overloaded Langston field is enough to vaporize whatever steel bulkheads you've got inside it. Only about half of the energy will be going inwards (I'm assuming it's proportional to surface area), the other half will be expanding out. While it'll be a lot more diffuse, I wouldn't want to be too close to an exploding ship for fear of overloading my own shields.
After a perusal of the book, I've still got a couple questions. What happens if two shields interact?
Let's say you put one inside another. That way, if your first shield blows, you've got another ready and waiting. Trouble is, when a shield blows it'll release a lot of energy. If the amount of energy a shield can store is proportional to the volume of space it occupies then the outer shield will by necessity be able to hold more energy. Consequently, when it releases all that energy it might overload the shield on the inside in just that one action. You could design around this though; by engineering your inside shield to have at least 51% of the energy capacity of your outer shield. Even if it only buys you a couple seconds, well, a couple seconds are valuable. We could assume as a principle of the physics that you can't have one shield inside another. Only that spells doom for making the drive ultraefficient.
Or what happens if you throw one field at another? Let's say you built Langston Fields into your torpedoes to make them harder to shoot down mid flight. When you launched it at another ship, what would happen? Well, let's say the fields cancel each other. Then you'd have an effective way to toss a torpedo through a field barrier, which makes the Langston field much less useful. Ok, what if the fields simply ignore each other. Then the torpedo would crash into the other ship's field, and work like described. Unless the torpedo would have a larger field, in which case it'd appear that the ship crashed into the torpedo's field, causing massive damage to the ship without injuring the torpedo. Also not optimal.
Let's see. The shields act to absorb incoming velocities. But you can impart a velocity to a shield by moving the generator on the inside. The shields are a projection of energy, but they also block energy. So if we assume that two shields would attempt to block each other out if they collided, then the two of them would have to absorb energy equal to the collective momentum of the system. Except that would leave them both at rest, and there's no reference frame to tell us what "at rest" means in that context. I could cheat by using the board to define a reference frame, but I'd rather not. One of the things I'm trying to do with this game is to not mess up the physics unless I absolutely have to. I can think of ways to explain the interaction of two shields, but none where the math will check out when two ships collide, and therefore none that I'd be happy using.
Ok, so suppose that it works that way. Well, possibly that I'll have to use a vector based movement system to describe how pieces move about the board. Honestly though, that'd probably happen anyway. Anything else? That it'll be possible to ram ships with other ships, for whatever purpose. Why would someone do that? Well, if you just hit them with a fusion torpedo their shield heats up. But if you sent in a spaceship on automatic you might be able to change their motion, say nudging them out of orbit or into the path of an asteroid or something.
Well, that's all the physics. Well, not all. I haven't touched on the thermodynamics much at all. Before I finish though, I'm going to add a couple restrictions to Langston Field Generators. Either they're really expensive to build, or they won't cover very small areas, or both. I'm saying this to limit the unintended consequences. If you could make cheap, small field generators then you could do all sorts of things with them. Really top notch fireproofing is probably the most boring. To limit the spread of miracle gadgets that do X, Y, or Z and implies T, U, and V, I think I'm going to limit these to small star ships and up.
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