Why Planteary Defense Weapons are Suicide

[BrokenSky]

@yerm
The decision to nuke a country does depend on whether it has anti-nuke defenses though. It's not the main consideration; not even close, but if it comes down below the dominant factors, then it matters. It also matters if you're considering a first strike.
Basically it kind of sends the wrong message if your would-be message of total destruction fails catastrophically.

The assumption then is, because as we all know; Space is an Ocean, that planet-side defenses are the analogue to shore defenses vs. Naval Fleets, that if they would be viable, they ought to be capable of putting a sufficient dent in the would-be attacking fleet to render mass destruction and salting of earth type attacks a hollow shell of the expected power, and hence deter all but the most desperate attackers for fear of the embarrassment, political and diplomatic damage and massive waste of resource of failing.

 

[yerm]

@yerm
The decision to nuke a country does depend on whether it has anti-nuke defenses though. It's not the main consideration; not even close, but if it comes down below the dominant factors, then it matters. It also matters if you're considering a first strike.
Basically it kind of sends the wrong message if your would-be message of total destruction fails catastrophically.

The assumption then is, because as we all know; Space is an Ocean, that planet-side defenses are the analogue to shore defenses vs. Naval Fleets, that if they would be viable, they ought to be capable of putting a sufficient dent in the would-be attacking fleet to render mass destruction and salting of earth type attacks a hollow shell of the expected power, and hence deter all but the most desperate attackers for fear of the embarrassment, political and diplomatic damage and massive waste of resource of failing.

For the first paragraph, I'm not sure I follow. The decision to nuke a country based on its defenses and counter-offensive capabilities just doesn't logically follow, in my mind, to a question of whether local defenses would be considered. In other words, the decision to glass a planet would depend on this analogous factors like the defenders capabilities, but not on whether they literally put silos on the ground or not. If your argument is that a space fleet would glass the planet because the defenses are too good to take down conventionally, that's fine, but it doesn't really matter at that point where or how those are arranged; the argument holds for orbital, lunar, ship-born, or grounded space fleet defenses just as much as planetary static ones.

For the second analogy, again, it doesn't follow to me. First off, you don't put your anti-ship weapons in the harbor when you can put them on the nearby hill's fort, hence my last paragraph saying you don't put your defenses on the ground when you can float them in orbit. Second, as before, the location of your anti-ship defenses is irrelevant to the decision of whether to bombard the town or nuke the planet.

So, to kinda clarify, I'm not arguing that there shouldn't be concerns about whether or not to glass a planet. I'm not arguing that there shouldn't be concerns about whether or not to do so based on the defender's capabilities. What I'm suggesting is that the nature and location of these is irrelevant; the decision is the same whether your silos are on the ground, on the moon, in orbit, on grounded spaceships, under the ocean, or all of the above. I am suggesting that, reasonably speaking, the attacker does not decide to obliterate a world because there are defenses on the surface when they would have decided not to do so if the defenses were instead in local orbit.

 

[Guthuk Gaming]

Have shields around the planetary defense weapons -> Fire from beneath the shields.

Otherwise you get issues like Endless Space has where you just go planet to planet and wars snowball completely out of control after one lost battle.

 

[BrokenSky]

For the first paragraph, I'm not sure I follow. The decision to nuke a country based on its defenses and counter-offensive capabilities just doesn't logically follow, in my mind, to a question of whether local defenses would be considered. In other words, the decision to glass a planet would depend on this analogous factors like the defenders capabilities, but not on whether they literally put silos on the ground or not. If your argument is that a space fleet would glass the planet because the defenses are too good to take down conventionally, that's fine, but it doesn't really matter at that point where or how those are arranged; the argument holds for orbital, lunar, ship-born, or grounded space fleet defenses just as much as planetary static ones.

For the second analogy, again, it doesn't follow to me. First off, you don't put your anti-ship weapons in the harbor when you can put them on the nearby hill's fort, hence my last paragraph saying you don't put your defenses on the ground when you can float them in orbit. Second, as before, the location of your anti-ship defenses is irrelevant to the decision of whether to bombard the town or nuke the planet.

So, to kinda clarify, I'm not arguing that there shouldn't be concerns about whether or not to glass a planet. I'm not arguing that there shouldn't be concerns about whether or not to do so based on the defender's capabilities. What I'm suggesting is that the nature and location of these is irrelevant; the decision is the same whether your silos are on the ground, on the moon, in orbit, on grounded spaceships, under the ocean, or all of the above. I am suggesting that, reasonably speaking, the attacker does not decide to obliterate a world because there are defenses on the surface when they would have decided not to do so if the defenses were instead in local orbit.

Wrt first paragraph: what I meant is that people are less willing to nuke a country if they don't think it would actually succeed unless they're desperate, furious or equivalent, though obviously I didn't convey this clearly.

Yes it might not. I'm not saying that ground defenses work or are better than orbital defenses. I'm saying that people are saying that, and I'm saying I think the reason they're saying that is because they're thinking too much with the "Space is an Ocean" trope. I would put defenses in orbit near exclusively, though some would be in orbit around mars to cover most of the blind spots.

Though I might be tempted to invest in a massive moon-based laser for fun.

 

[Maarten99]

I also can't understand a good reason to put weapons on the surface if we assume that technology allows putting objects in orbit to be trivial.

Energy - on the surface, you could in theory feed your weapon almost infinite energy, whereas energy available on a ship is limited.

 

[grisamentum]

Energy - on the surface, you could in theory feed your weapon almost infinite energy, whereas energy available on a ship is limited.

Nope. This is a major misconception I keep seeing.

Whatever your source of energy is, you can build it more easily and better in space. More importantly you can build it denser in space, because in space you can build in three dimensions better than you can on a planet surface.

Unless, of course, we're talking about one single mega laser cannon that the entire planet is devoted to feeding. In that case it would be a major effort to rebuild such a power infrastructure in space.

Of course, then I'd just keep my fleet on the other side of the planet...

 

[BrokenSky]

Nope. This is a major misconception I keep seeing.

Whatever your source of energy is, you can build it more easily and better in space. More importantly you can build it denser in space, because in space you can build in three dimensions better than you can on a planet surface.

Unless, of course, we're talking about one single mega laser cannon that the entire planet is devoted to feeding. In that case it would be a major effort to rebuild such a power infrastructure in space.

Of course, then I'd just keep my fleet on the other side of the planet...

Geothermal.



Also Wind, Tidal, Hydroelectric.

Also that isn't true if you use any kind of fuel, because you have to spend a TON of energy moving that much fuel into orbit to your dedicated weapons platform. The only thing space-bound platforms are better at getting is solar power, though that is a viable source there.

 

[grisamentum]

Geothermal. Also Wind, Tidal, Hydroelectric.

Also that isn't true if you use any kind of fuel, because you have to spend a TON of energy moving that much fuel into orbit to your dedicated weapons platform. The only thing space-bound platforms are better at getting is solar power, though that is a viable source there.

Solar in space beats all of those, of course.

But more realistically, you're either going to beam the power to the platform wirelessly, or you're going to have a reactor in space (since we're sci-fi, that's fusion or antimatter, right?). Which is also a nuclear reactor in space, because it doesn't need as much shielding as a terrestrial reactor (assuming we are talking about an unmanned platform).

And why in the world would you be sending maneuvering fuel into orbit? You're mining it in orbit if anything. And until the platform is actually attacked it doesn't even need to use much propellant; it's in a stable orbit.

 

[bz249]

Nope. This is a major misconception I keep seeing.

Whatever your source of energy is, you can build it more easily and better in space. More importantly you can build it denser in space, because in space you can build in three dimensions better than you can on a planet surface.

Unless, of course, we're talking about one single mega laser cannon that the entire planet is devoted to feeding. In that case it would be a major effort to rebuild such a power infrastructure in space.

Of course, then I'd just keep my fleet on the other side of the planet...

Nope you cannot if the laws of thermodynamics apply. The planet is a big heat sink where you can dump your waste heat. In space you have only one option: radiate it away. Since radiative energy transfer is proportional to the forth power of the surface temperature it is mightily inefficient at temperatures where complex organic or semiconductor thingies can function.

Edit: i kinda sure that thermodynamics does not exist in the game universe

 

[BrokenSky]

Solar in space beats all of those, of course.

But more realistically, you're either going to beam the power to the platform wirelessly, or you're going to have a reactor in space (since we're sci-fi, that's fusion or antimatter, right?). Which is also a nuclear reactor in space, because it doesn't need as much shielding as a terrestrial reactor (assuming we are talking about an unmanned platform).

And why in the world would you be sending maneuvering fuel into orbit? You're mining it in orbit if anything. And until the platform is actually attacked it doesn't even need to use much propellant; it's in a stable orbit.

If by beats all of them you mean that the others are impossible to do in space then yes. Otherwise... Wind and Hydro are less efficient solar power but the whole planet is your solar panel so it still might be better, depending on how much of the planet's power is diverted. Geothermal uses radioactivity and Tidal uses gravity; again it depends how much you're willing to sink into massive guns.

Also wirelessly beaming power to the platform is a joke. If you can transfer energy that easily into space, you can make guns that deliver it right to the enemy ships, instead of having to route through a second, inefficient station en route.

Wrt reactors, sure you have more space in space, but you'd have to ship fuel and that would be a total dog to deal with. You need to use propellant to move the fuel to the platform. It needs to be powered constantly so the computers are on to pick up signals, which means constant refueling whether you're at war or not.

Again, only solar power is viable for space mounted defenses.

Nope you cannot if the laws of thermodynamics apply. The planet is a big heat sink where you can dump your waste heat. In space you have only one option: radiate it away. Since radiative energy transfer is proportional to the forth power of the surface temperature it is mightily inefficient at temperatures where complex organic or semiconductor thingies can function.

Edit: i kinda sure that thermodynamics does not exist in the game universe

Could you make the weapon the heat-sink?

 

[grisamentum]

Nope you cannot if the laws of thermodynamics apply. The planet is a big heat sink where you can dump your waste heat. In space you have only one option: radiate it away. Since radiative energy transfer is proportional to the forth power of the surface temperature it is mightily inefficient at temperatures where complex organic or semiconductor thingies can function.

Isn't that always your only option? The question is about the engineering of radiating it away. There's nothing special about the planet that gives you some other option. Heat radiates. The question is where you send it and what you do with it.

And the planet is a much warmer heat sink, isn't it? In space you can easily have something sitting at single digits kelvin; like 5 - 10 is easily achievable without any active cooling. So what you could do is have heat sink cartridges that you vaporize/eject and then slot in another.

Alternatively, there are all kinds of technologies for converting waste heat into something else that you can then radiate/dump/emit into space. You could have an optical heat pump, for example. Again, this is an engineering problem, not an inherent disadvantage to an orbital platform. You have to cool a giant laser on a planet too, and you have to do it without melting your installation's foundations or frying your atmosphere (actually, the environmental damage caused by a lot of giant lasers is an interesting problem, like converting significant percentages of own atmosphere to ozone, for example).

 

[grisamentum]

If by beats all of them you mean that the others are impossible to do in space then yes.

No, I mean that the power sources you're describing are minuscule compared to solar in space. The total tidal power of the entire Earth is something like 100 gigawatts. I don't mean "what we currently make" from tidal power, I mean the total possible amount of tidal energy available. That's about what the United States makes RIGHT NOW from nuclear reactors, with outdated reactors, and just the US. Same story with geothermal and wind - the scales of the energy you're talking about are just tiny.

Otherwise... Wind and Hydro are less efficient solar power but the whole planet is your solar panel so it still might be better, depending on how much of the planet's power is diverted. Geothermal uses radioactivity and Tidal uses gravity; again it depends how much you're willing to sink into massive guns.

The "whole planet" isn't your solar panel. Only the part that's facing the sun, and it's under an atmosphere that reflects light - not to mention clouds. An orbital panel is vastly more efficient.

Also wirelessly beaming power to the platform is a joke. If you can transfer energy that easily into space, you can make guns that deliver it right to the enemy ships, instead of having to route through a second, inefficient station en route.

Uhh... no. Just because you can diffusely send power - at a convenient wavelength - to a rectenna, that doesn't mean you can also concentrate that power into a militarily useful laser. If your argument was correct then we would be best served by just setting up a lot of orbital mirrors and reflecting sunlight at the attacking fleet. That's EVEN more efficient than gathering the sunlight on the surface and sticking it into a dumb laser... right?

Wrt reactors, sure you have more space in space, but you'd have to ship fuel and that would be a total dog to deal with. You need to use propellant to move the fuel to the platform. It needs to be powered constantly so the computers are on to pick up signals, which means constant refueling whether you're at war or not.

What are you talking about, a coal-fired platform? This is nuclear physics, man. The amount of fuel for the reactor is measured in grams, and that's just for firing the weapon. When the station isn't firing it can presumably live off its solar panels.

 

[BrokenSky]

Isn't that always your only option? The question is about the engineering of radiating it away. There's nothing special about the planet that gives you some other option. Heat radiates. The question is where you send it and what you do with it.

Dealing with this is what cooling towers are for. Why else do you think they give off all that steam?

And the planet is a much warmer heat sink, isn't it? In space you can easily have something sitting at single digits kelvin; like 5 - 10 is easily achievable without any active cooling. So what you could do is have heat sink cartridges that you vaporize/eject and then slot in another.

Not really. In space you can only radiate, but on earth, assuming you forgo cooling towers for whatever reason you can conduct away heat, and +this is much easier for heat dissipation than radiating alone..

Alternatively, there are all kinds of technologies for converting waste heat into something else that you can then radiate/dump/emit into space. You could have an optical heat pump, for example. Again, this is an engineering problem, not an inherent disadvantage to an orbital platform. You have to cool a giant laser on a planet too, and you have to do it without melting your installation's foundations or frying your atmosphere (actually, the environmental damage caused by a lot of giant lasers is an interesting problem, like converting significant percentages of own atmosphere to ozone, for example).

The main inherent problem with a ground based laser is the fact that the atmosphere absorbs a lot of the energy. Making ozone is only a byproduct of this. Note that radiating energy into space from the planet, as you previously suggested would have the exact same problem.

edit: that heat pump is just another way of exclusively radiating heat. There are better ways for heat dissipation; as far as I can tell, this is for creating a temperature difference from an equilibrium by doing work, which is unimportant here, since the thing we want to cool is hotter than the environment.

(You know it always annoys me when people doing the whole environmental thing show the cooling towers and say that they're giving off greenhouse gasses. I mean yes water is a greenhouse gas, technically, but it's really insignificant.)

No, I mean that the power sources you're describing are minuscule compared to solar in space. The total tidal power of the entire Earth is something like 100 gigawatts. I don't mean "what we currently make" from tidal power, I mean the total possible amount of tidal energy available. That's about what the United States makes RIGHT NOW from nuclear reactors, with outdated reactors, and just the US. Same story with geothermal and wind - the scales of the energy you're talking about are just tiny.

Perhaps compared to the total power one could derive from utilizing all the available solar energy, but certainly not what you could do in any realistic scenario where you'd still need weapons to defend yourself. Except tidal. Tidal isn't big. Geo is could be massive though, if you went to the level of efficiency you seem to be assuming, since that's basically just repurposing the entire planet into a single giant nuclear power plant. why you'd want to defend it at that point is kind of moot but eh.

An orbital panel is vastly more efficient.

And of comparatively negligible size. Besides; I said that it was less efficient, but much bigger. That was my point. It only applies, again, in the unrealistic senario where the whole planet is your weapon.

I would like to state, yet again, that I think that the best solution is STILL solar powered orbital defenses, supported by a giant f***ing laser on the moon.

 

[freeaxle]

I agree with most of what you said, but a few points:
Sent from the planet it has a short distance to accelerate, from the fleet they could place engines on the comet and have it accelerate steadily for months or years. They could definitely target a fleet, but once they get to a certain range it's probably next to impossible to hit them whereas the planetary position is predictable.

I can see your point. I think it takes a couple of assumptions, 1. that it is possible to calculate a long shot (years/months of acceleration) and 2. that the sort of acceleration necessary to intercept it from the planet is difficult/impossible once they notice it is incoming. Not to say I think those are necessarily wrong, I think they are valid assumptions, but they are assumptions . So, taking these constraints into account, I would say the efficacy of the planet based defence systems would depend on how quickly they could notice and then respond to the asteroid. My argument for this scenario though (the sneaky long-shot) is that it is not the sort of scenario planetary defences would be good for - this is where a defence in depth tactic makes more sense (eg. batteries, sensors and ships on the edge of the system). From a game perspective, it is more interesting if you require a defence in depth approach (eg. orbital, system AND planetary based defences) to really achieve an effective defence.

Definitely. Problem is if you want to keep your people alive as well.

You're right, to an extent. The point of a defence system is to raise the potential cost of conflict - even if you don't anticipate that you'll use all of your options. There is a great Yes Prime Minister episode about the use of Nuclear Weapons - the idea being that even though you possess nuclear weapons as a deterrent, you may not ever use them. So the idea behind strengthened points buried deep within the planet is to suggest to an enemy that it is very likely that in order to succeed in their invasion they have to cause significant damage to the planet, raising the cost of the invasion and thus acting as a deterrent. This is true, even if you plan to surrender the planet before things get to that point.

edit: "Respectfully Disagree"? Oh yeah? Which part?

Well that wasn't me - but here's where I'll go through my respectful disagreement

I think you're conflating too many things here. For one thing, having a space elevator means infrastructure for putting cargo in orbit. It doesn't mean you have an effective anti-space missile battery or anti-space cannons of some kind.

It's a fair point, but I still stand by my original position. My point about getting cargo into orbit cheaply and effectively was a counter-point to those who put the gravity well of a planet up as an absolute barrier to a planet based defence system. Even if the system is slow (say a space elevator), it will be able to get weapons into orbit where they can be used. To be fair, that's moving away from a planet based defence system to a... planet supplied? weapons system.

That said, I don't think it's beyond the realm of possibility to suggest that we will have a system much better able to get things into space at high speeds in the not too distant future. In fact, it's hard to imagine that missiles in the future aren't able to escape orbit easily. If an object can accelerate quickly enough, then the force exerted by Earth's gravity is trivial compared to that exerted by the engine (please don't jump on me physics people ).

Second, it doesn't matter if you have an "effective" ground-based weapon. The point is that it would be a better weapon in orbit. A laser cannon battery, of any strength, is simply a better laser cannon battery if it's on a platform in orbit. Same thing with a missile battery. Why? Mainly because of the atmosphere and gravity. Shooting a laser through an atmosphere is a huge waste of destructive potential compared to firing it in a vacuum. Same thing with firing a missile out of a gravity well. Given the same engine and the same fuel, you can put a bigger warhead on a missile fired from orbit.

Almost certainly true of lasers, but I'm not convinced about other weapons. I would certainly agree that there are advantages (as you have mentioned) but there are advantages to planet based defences as well. On a side note, I am definitely not arguing for planet based vs orbital, I think there is a place for both and it would be sad if Stellaris didn't reflect that.

As for planet based defences - they are easier to hide (I will get to that ) easier to reinforce (bury them in the ground), which makes them less susceptible to disruption from enemy ships. In addition, they will have access to the planetary energy grid, so while they may be less efficient, they may well be orders of magnitude more powerful. Particularly as they can be hidden, they don't make quite the same target-size vs power (stored ammunition, size of the weapon etc.) trade-off that orbital weapons do.

I've seen someone argue that it's "harder to destroy" if it's on the surface. But how? Because you buried most of it under some rocks? And why do you think you can't do that in space? Rocks are really, really cheap and easy to find in space. If you want to surround your weapon with tons of rock, that's trivial to do in space, and you get exactly the same defensive advantages. Plus, your orbital platform has a major defensive advantage: it's moving! You can put thrusters on it and move it around! Even if it's also covered in tons of rocks!

Yes you can collect lots of rock for your weapon platform, but the bigger it is, the more obvious a target, losing it's mobility and small profile advantages. Earth weapons can be buried underneath kilometres of rock and become less obvious. The moving part helps I suppose, but if it's an orbital platform then its movement is pretty predictable anyway.

Yep. At least for organisms with human-like bodies. AI or some other kind of non-animal sentience, who knows.

This point I can't argue with - but I suppose in the context of Stellaris that's less of an issue - we can assume our enemies have bodies and want to physically occupy planets

It depends on your goals and planning scale. If you're only even going to build artificial habitats on/around the planet, who cares if you completely ruin its surface and atmosphere? I mean, sure, radiation from nukes could be a problem, but you can probably just throw lots of fast dark rocks at the planet to fry its surface. Or if you're not planning on colonizing it for decades anyway, nukes work just fine.

Sure, if you're already going to build artificial habitats. Sure, if you're not interesting in harvesting biological, or even surface non-biological resources, then there is no real drawback to glassing/nuking a planet. Assuming those are something you're interested in (and again, in the case of Stellaris I think we are) then having to do those things raise the cost of invasion - which is the point of a defence system.

There's "fast" and then there's relativistic speeds. Even the fastest-moving comets and asteroids are very, very slow. Even a comet on a sungrazing course, whipping around Sol, doesn't even reach 500,000 mp/h, or less than 1/1000 the speed of light. We could get into a whole debate about how easy it would be to create a military projectile that was invisible and capable of decimating or even destroying a planet, and what level of solar system infrastructure you'd need to ensure nobody did that, but it doesn't matter. The real point, again, is that any anti-asteroid defense platform you want to have is better if it's in orbit. It can detect things sooner and more accurately, it can maneuver, etc etc. There's just no reason to put it on the surface.

I agree, orbital platforms have a purpose as well, and detecting a long range projectile that has been given a lot of space to reach some incredible speed would be one of those things. In fact, I would argue a defence in depth approach, with a system of batteries and sensors would be optimal. I believe I have already gone into detail about a similar point above

Nope, just the opposite. The planet is a gigantic gravity well. All things being equal the fleet can launch bigger, faster missiles, because they don't have to overcome the planet's gravity.

You're forgetting that ships are much, much smaller than planets and have to use their limited space/resources for a whole host of other things. All things being equal, the planet can launch bigger, faster and more missiles as it doesn't have to worry about transporting them. This becomes untrue with a sufficiently large fleet - so I suppose the point of contention here would be how large a fleet do you need to match the potential arsenal of a planet?

No way. A fast enough object would have no problem cracking a planet open or even completely destroying it. Destroying anything on the surface is trivial. You wouldn't even need a relatively large asteroid if you could get it going fast enough. There are plenty of asteroids in the 200 km^3 range (asteroids get much, much bigger) with masses on the order of 30x10^18 kilograms. If you have space travel technology and you can accelerate it up to even 1% of c, you're going 1000 times faster than any asteroid we've ever seen, and the impact damage would easily knock a chunk off the planet. Not to mention that you could easily aim it for a direct impact, not an oblique entry from orbit.

If you go deep enough... but I do see your point. In that case, the bunker has achieved its objective in preventing occupation/use of the planet - raising the costs and decreasing the benefits of invasion.

Depends on the projectiles (rockets are going to be detectable as soon as they leave a silo because of their heat signature), but either way it's equally true of hiding projectiles in a dark satellite. Except your dark satellite can also move.

On this point I absolutely disagree - though dark satellites, or even inactive rockets in orbit would be effective. But, one shot weapons aside, Earth is much better at hiding weapons. Firstly, a planet, especially an advanced one, will have a whole heap of heat, and in fact, with the storage capacity of a planet it wouldn't be hard to generate false ones, or so many that it would overwhelm a defence system. So, you have to have, on your fleet a system of sorting through all of the heat signatures to find ones that aren't false positives.

Now, I'm going to go out on a bit of a limb here, so bear with me, or feel free to (respectfully) tell me where I have made erroneous assumptions I don't really know how you detect heat signatures - but let's assume that you have to be able to scan the surface of the Earth to detect a signature - that's about 510 million square kilometres (so wikipedia informs me) you have to scan. You then have to track matches, discarding false matches. Working out the source of the weapon would require yet more computation. This would require a huge amount of computing power, which would have to be dedicated solely to the task of detecting incoming projectiles.

Of course, you can cut down this power by only focusing on a smaller area, or by looking at objects in space where there are presumably fewer sources of noise that have to be dealt with.

But more importantly, the fleet has similar advantages. You can easily throw rocks at Earth from behind the Moon, and nobody is going to see you.

Sure, if a fleet can get behind a blocking object then it might be fine, but given how cold and empty space is, it's much harder to hide a ship than an object on a planet which is hiding a warm object in a warm environment. But that point about sneaky rock lobbing I think goes back to the point that there is a place for system, orbital and planetary based weapons and sensors.

No way. Planets are death traps.

I am guessing we won't see any of the considerations discussed above. It'll all be magic laser cannons shooting from the planet into space. But that doesn't mean it won't be a fun game. Like many other Paradox games, reality is considerably less exciting.

I suppose my main point is that planetary defences have a place, which is mainly system denial against a fleet, whereas orbital and system based defences are better against long range bombardments (assuming low levels of acceleration (relativistically speaking ).

I hope Paradox surprises us all and gives us something awesome here instead of magic laser cannons .

 

[Kuschelflummi]

To sum the whole point up: If someone has nucelar weapons, its would be suicide to build something against it.

Some people have Ideas...

 

[BrokenSky]

Uhh... no. Just because you can diffusely send power - at a convenient wavelength - to a rectenna, that doesn't mean you can also concentrate that power into a militarily useful laser. If your argument was correct then we would be best served by just setting up a lot of orbital mirrors and reflecting sunlight at the attacking fleet. That's EVEN more efficient than gathering the sunlight on the surface and sticking it into a dumb laser... right?

It not that you could do that, it's that the main thing which limits ground to space lasers, also limits most frequencies which you'd be sending power on. If you did get round that, though, there's always the drop off from long range. Gonna go as 1/(r^2) and be totally inefficient.

What are you talking about, a coal-fired platform? This is nuclear physics, man. The amount of fuel for the reactor is measured in grams, and that's just for firing the weapon. When the station isn't firing it can presumably live off its solar panels.

A common misconception. A nuclear reactor uses a very large mass of fuel for several reasons, most andmportant being that only 5% of the mass is usually the actual fuel, that the reactor normally has enough fuel to run for 3 years without stopping. The thing which is measured in grams is the DIFFERENCE IN MASS between the fuel going in and the fuel coming out. Nuclear fuel is measured in kilograms, because everything is measured in kilograms, even that thing I just said was measured in grams - it isn't it's measured in kilograms, and the number of kilograms of fuel is pretty large.

Though yes, solar panels would be good for the computing needs of the non-gun systems. Or, if you used all that space you're giving over to nuclear reactors and large docking bays to unload vast quantities of pre-enriched fissile material to build large electrical batteries and a few more solar panels, you could run the whole thing off solar, which would get around the logistical issues which would otherwise make the whole thing laughable.

 

[Praetori]

Isn't that always your only option? The question is about the engineering of radiating it away. There's nothing special about the planet that gives you some other option. Heat radiates. The question is where you send it and what you do with it.

That's just a grossly uninformed argument as it completely contradicts all IRL engineering problems with spacecraft compared to planetary operations. If you're surrounded by vacuum there's only one out of four options available for you to get rid of heat (and get rid of it you must or you start melting due to diffusion, convection and conduction internally at some point) and that is through radiation. Just like any thermodynamic system a spaceship is no different from a planet, it just has a lot less mass and a lot less surface area (a lot lot less) to act as a heatsink and radiator which means it usually gets hot, and fast, if there are internal processes converting energy. A planet will also get hot but at a astronomically slower pace due to it's mass and large surface area (so large a difference that you don't need to worry about planets getting rid of excess heat, global warming aside).

The problem is that radiation is vastly less efficient than the other three forms, or rather conduction (that's the principle behind why the planet you're living on isn't a frozen ball of ice) and without some marvels of engineering (which would also be available to a planetary system) you cannot simply magically turn heat into photons without also conducting the majority of the energy to other parts of your spacecraft (it's a fundamental part of thermodynamics). If you through some undisclosed tech COULD choose where to steer the energy you enter uncharted territory and basically anything goes (like a 100% efficiency IR-laser) and still the same technology could be employed by a planet (say hello to the energy-cannon powered by a planetary core).

Also radiating heat is like turning on a big flashlight screaming "here I am" (photons as photons).

 

[permanently_afk]

edit: "Respectfully Disagree"? Oh yeah? Which part?

Me. And there is no reason to be so uncivil. And I disagree because I find your reasoning lacking.

I think you're conflating too many things here. For one thing, having a space elevator means infrastructure for putting cargo in orbit. It doesn't mean you have an effective anti-space missile battery or anti-space cannons of some kind.

Oh, it does. The materials science required to build a space elevator and a space gun is relatively similar, since both require high strength. So yes, the ability to easily transport civilian loads to orbit leads to efficient orbital guns.

Second, it doesn't matter if you have an "effective" ground-based weapon. The point is that it would be a better weapon in orbit. A laser cannon battery, of any strength, is simply a better laser cannon battery if it's on a platform in orbit. Same thing with a missile battery. Why? Mainly because of the atmosphere and gravity. Shooting a laser through an atmosphere is a huge waste of destructive potential compared to firing it in a vacuum. Same thing with firing a missile out of a gravity well. Given the same engine and the same fuel, you can put a bigger warhead on a missile fired from orbit.

On the part of lasers and particle weapons, I agree with you. On the part of missilies, the ground installation could easily use a giant (well hidden) rail gun to propel the missile into the upper atmosphere, where it ignites its drives. Also, the fundamental advantage of the ground is, as many have pointed out, to store/launch a larger number of larger missiles.

I've seen someone argue that it's "harder to destroy" if it's on the surface. But how? Because you buried most of it under some rocks? And why do you think you can't do that in space? Rocks are really, really cheap and easy to find in space. If you want to surround your weapon with tons of rock, that's trivial to do in space, and you get exactly the same defensive advantages. Plus, your orbital platform has a major defensive advantage: it's moving! You can put thrusters on it and move it around! Even if it's also covered in tons of rocks!

Tons of rocks means bigger target, means more fuel, means even bigger target. If you put anything in space you are bound by the mass/target size tradeoff. So you put the target data feeds into the orbitals, stealth them well and put the actual launching mechanism/magazines on the planet.

There's "fast" and then there's relativistic speeds. Even the fastest-moving comets and asteroids are very, very slow. Even a comet on a sungrazing course, whipping around Sol, doesn't even reach 500,000 mp/h, or less than 1/1000 the speed of light. We could get into a whole debate about how easy it would be to create a military projectile that was invisible and capable of decimating or even destroying a planet, and what level of solar system infrastructure you'd need to ensure nobody did that, but it doesn't matter. The real point, again, is that any anti-asteroid defense platform you want to have is better if it's in orbit. It can detect things sooner and more accurately, it can maneuver, etc etc. There's just no reason to put it on the surface.

I am quite certain that if you have enough energy (and energy generation methods) to accelerate objects of non-trivial mass to relativistic speeds, you can build a death-star planet destroying laser. So I am going to disregard any argument in the category "assualt by relativistic meteor" as "game ender superweapon"

Nope, just the opposite. The planet is a gigantic gravity well. All things being equal the fleet can launch bigger, faster missiles, because they don't have to overcome the planet's gravity.

No, the opposite. A planet does not have to contend with considerations such as "limited storage space for ship systems", "mass/targetsize tradeoff" or limited fuel/food/endurance. A planetary missile base can simply railgun the projectiles into the lower atmosphere. Of course, if you want to be especially devious, you place the missile base on a moon, where it has both cover and lower gravity. And then a single base could potentially bury your fleet with multiple loads of their entire magazines worth. I think you underestimate how big a moon or planet are and how small in comparison spaceships are. I recommend playing Kerbal Space Program for the feeling and then remembering that everything in there is half or quater size of the "real thing"

Depends on the projectiles (rockets are going to be detectable as soon as they leave a silo because of their heat signature), but either way it's equally true of hiding projectiles in a dark satellite. Except your dark satellite can also move.

But more importantly, the fleet has similar advantages. You can easily throw rocks at Earth from behind the Moon, and nobody is going to see you.

As stated above, rockets can be propelled by railguns, whose electronic discarge wouldn't be visible from orbit. Then they ignite their drives in the upper atmosphere and then there is a hell of a lot of places where the silo could be. The dark satelite may move, true, but it also has a very limited magazine capacity. It is a one-shot weapon.

No way. Planets are death traps.

Nope. For the invader maybe, but the defender has a large advantage. Planets are like cities in modern warfare. They produce all the things you want for war, but can be horrible meatgrinders. Of course, if you can just blow it up, but then you lose all the infrastructure and resources. As freeaxle has pointed out, if you want to get anything out of the system, it is in your best intrest to take the planet as intact as possible. The defender of course will want to raise the cost for that, forcing you to either invest a lot in taking the system or a lot into its reconstruction. Either way planetary and system defense is a way to make it pohibitively expensive.

On the topic on detecting: An atmosphere hides a lot. I once had to work with radar data, and a few friends of mine worked on LIDAR so I know that ferreting out the positives from a noisy environment is hard, even without someone actively throwing around false positives. To carry out effective bombardment you either need to get close (i.e. planetary orbit) or you need ultra-fancy sensors. So ploking down on the other end of the system and bombarding from there is a bit of a misconception.

For a litte example, take Sol in a hypothetical mid game.
Earth itself posesses multiple well-hidden missile bases, as does Luna. These use railguns fed of the planetary grid to launch their missiles. They only ignite in lower orbit and are larger than conventional fleet missiles, but just als well hidden (the larger size means more room for ECM and maneuvering fuel in addition to a larger warhead). Targeting data is fed to the missiles by stealth satelites. In addition, various mines and single-launch satelites are placed around the solar system.
The other major planets (Mars, Saturnian moons) posess the same systems. In addition, a small fleet patrols the system. Or Home Fleet is home, which means that a lot of ships and missiles stand ready to crush any hope of victory. The Batteries mean that the Admiral of Home Fleet can basically call in off-map artillery during any space battle^^

In essence, planetary defenses fulfill one of two purposes:

1. Discourage raiding from either hostile flotillas or pirates
2. Integrated part of a system fortress in concert with orbitals and a system defense fleet. In this case they act the part of heavy guns or offmap support

 

[grisamentum]

That's just a grossly uninformed argument as it completely contradicts all IRL engineering problems with spacecraft compared to planetary operations. If you're surrounded by vacuum there's only one out of four options available for you to get rid of heat (and get rid of it you must or you start melting due to diffusion, convection and conduction internally at some point) and that is through radiation. Just like any thermodynamic system a spaceship is no different from a planet, it just has a lot less mass and a lot less surface area (a lot lot less) to act as a heatsink and radiator which means it usually gets hot, and fast, if there are internal processes converting energy. A planet will also get hot but at a astronomically slower pace due to it's mass and large surface area (so large a difference that you don't need to worry about planets getting rid of excess heat, global warming aside).

The problem is that radiation is vastly less efficient than the other three forms, or rather conduction (that's the principle behind why the planet you're living on isn't a frozen ball of ice) and without some marvels of engineering (which would also be available to a planetary system) you cannot simply magically turn heat into photons without also conducting the majority of the energy to other parts of your spacecraft (it's a fundamental part of thermodynamics). If you through some undisclosed tech COULD choose where to steer the energy you enter uncharted territory and basically anything goes (like a 100% efficiency IR-laser) and still the same technology could be employed by a planet (say hello to the energy-cannon powered by a planetary core).

Again, I get all that. And of course you can more easily cool the laser on the ground, but it also needs to be a lot more powerful from the ground because you lose so much power shooting through the atmosphere. The laser is smaller and vastly more efficient because its in orbit.

Also radiating heat is like turning on a big flashlight screaming "here I am" (photons as photons).

Presumably the laser cannon you're shooting out of your orbital platform would give the same indication, and you're only radiating serious heat after you fire that, so...

 

[ParagonExile]

Never underestimate a sci-fi community's willingness to argue the details of something. This thread taught me that.

EDIT; Being pretentious is fun. Sorry :C