Big honking space gun: ground or space based?

[Destructionator XV]

Lets say you wanted to create a huge space gun (a weapon to shoot down spaceships, like the Ion Cannon from ESB).

Would it be better to place one on the ground, where the planet wold absorb the momentum and possibly have bigger power facilities for it

or

put it in orbit on a space platform where there would be no worry of the planet's atmosphere messing up the weapon?

[The Cleric]

Lets say you wanted to create a huge space gun (a weapon to shoot down spaceships, like the Ion Cannon from ESB).

Would it be better to place one on the ground, where the planet wold absorb the momentum and possibly have bigger power facilities for it

or

put it in orbit on a space platform where there would be no worry of the planet's atmosphere messing up the weapon?

Ground. The recoil would be massive on that.

[Stofsk]

Why a gun? Why not missiles? I would put a missile platform on an orbital, and as for guns it would depend on what type they were. Lasers? Railguns? Meson guns?

Ideally I'd want mobile battleships in orbit to provide the main line of defence. An orbital fortress to fire missiles in support of the battleships. Perhaps even mine any likely orbital approaches for reentry with nuclear devices. (not likely to kill anything, but you could get lucky) Laser guns on the surface would act like the NMD project currently being developed. They would intercept incoming missiles and act as a last-ditch screen against invaders.

Of course, if I had a Meson gun I'd build nothing else but them - two, in fact, one big arse Meson cannon in the center of town, daring anyone to attack, and another buried kilometers under the surface as a 'surprise!' back up weapon. (Meson guns are something from the game Traveller. Basically they fire highly energetic particles called Mesons that can penetrate anything, and are timed to decay just as they penetrate the armoured hull of enemy starships.Because they can go through anything you can build cannons under the surface of the planet where they wouldn't be touched by orbital bombardment, but where they can strike back with impunity - Ah - ah - AHHHHhhh...).

Wow. That gun wanking felt good.

What brought on this topic? You planning on building weapons of mass destruction or something?

[Destructionator XV]

This was brought on by the STGOD. I am going to bring up the fact that I have some planetary defenses, which I figured would be like the Ion Cannon from Empire Strikes Back, shooting awesome blasts into the sky to shoot down enemy starships.

But I started thinking about how atmospheres have a nasty habit of absorbing energy. For example, NASA was thinking about using ground lasers to transfer energy to spacecraft, cutting down on the amount of fuel they would have to carry on them, but they are having problems with water vapour in the air absorbing most the laser's energy before it got all the way to the shuttle (in their calculations IIRC; I don't beleive they ever tried building one for actual experimentation)

Consider something similar happening with high end sci-fi beam weapons. The amount absorbed by the atmosphere would weaken the blast, but more importantly, it might leave a trail of plasma between the gun and, well all the way up into space until the atmosphere becomes too thin to support it. This superheated air could be a major problem to whatever is close to the gun, causing damage.

Momentum from a beam weapon would be an insignificant concern, because a beam would have little mass (or would it?). More massive the weapon, the more energy it must expend just to get from the surface into space where it can hit enemy vessels. Of course, this energy would be negligable to an interstellar sci-fi race anyways.

A good thing about the ground is it could be attached to a massive planetary power grid and may be safer from attack than a space platform. Space missile platforms would certainly also be a good idea.

[Knife]

Depends on capability, I would imagine, as well as other assets. The Hoth cannon worked well since it only had to cover a certain arc and provide cover for an tiny little bit of land.

If this is what you got, a small base on a big planet or even just on major population center, then ground based would seem a good choice. If you need to cover larger areas and have a better field of fire, then orbital based weapons would be better. And better than that, a network of mutually supporting space fortresses.

Though if it were a kenitic weapon or plasma or another weapon that would loose substantial energy to the atmoshpere either jsut by radiating or expending too much energy to gain orbit, then ground based would be bad. But again, if you're goning to produce a shit load of momentum by shooting the weapon, say the classic rail gun, then orbital is bad.

Basically, you're going to have to strike a balance. Which is ok, that gives you an excuse of combined arms in your defense.

[frigidmagi]

If I was facing a planet with a big honking gun, I would just keep most of the planet between me and the gun, blow open an LZ and send in troops to take care of it. What are you gonna do? Shoot through the planet? Way to defeat the purpose there.

Even if you have them scattered across the planet I can engage the guns in detail with my invasion fleet has I prefer... Or just start dropping large rocks in large numbers into your gravity well. Hope you're well dug in, you'll need to be.

Against an enemy fleet, it is my belief the best defese is having your own damn fleet. Fortications can do damage and have a place but against a determined foe who knows what's he doing, they won't last long in this context.

[Knife]

If I was facing a planet with a big honking gun, I would just keep most of the planet between me and the gun, blow open an LZ and send in troops to take care of it. What are you gonna do? Shoot through the planet? Way to defeat the purpose there.

Even if you have them scattered across the planet I can engage the guns in detail with my invasion fleet has I prefer... Or just start dropping large rocks in large numbers into your gravity well. Hope you're well dug in, you'll need to be.

Against an enemy fleet, it is my belief the best defese is having your own damn fleet. Fortications can do damage and have a place but against a determined foe who knows what's he doing, they won't last long in this context.

I agree, though when it comes to defense, it is probably cheaper and more efficent to have static defenses to free up mobile assets to counter attack and or commence a counter offensive in a larger scale on enemy territory.

[Stofsk]

If I was facing a planet with a big honking gun, I would just keep most of the planet between me and the gun, blow open an LZ and send in troops to take care of it. What are you gonna do? Shoot through the planet? Way to defeat the purpose there.

In comes the almighty Meson cannon, which CAN do just that.

[frigidmagi]

In comes the almighty Meson cannon, which CAN do just that.

And ripped through howmuch of your population and went through how many kilometers of solid plant before even coming anywhere near my ships? Oh yeah, not only does that defeat the purpose of defending them, odds are I can see it coming and dodge.

Thanks for doing the bombing work for me.

[Stofsk]

Mesons don't harm what they go through, it's until they 'decay' which is when the fireworks start.

So I can construct an underground - by that I mean several kilometers deep - cannon emplacement which can shoot up at ships in orbit. The mesons fire through the solid rock and anything in between without harming the intervening matter. The cannon has a program that 'times' when the particles decay, which coincides with when those particles should be hitting the enemy ships. Meanwhile the enemy ships can do nothing but die because they can't penetrate the solid rock with their weapons, unless they too carry meson cannons - in which case they're still screwed, because finding an underground cannon would be problematic while you're trying to dodge that same cannon.

Meson cannons = magic scifi weapon. I only brought them up because I thought they were a cool idea, and because I didn't think the guy was serious about constructing a real-life weapon's battery.

[frigidmagi]

This idea of being helpless is a incorrect, you can still blow your way down into an enemy's dug in postion. Also if I'm the other side of the planet, magic or no magic, I have doubts about it's ability to shot through the planets very core and somehow still get at me without me even noticing it's coming.

[Stofsk]

This idea of being helpless is a incorrect, you can still blow your way down into an enemy's dug in postion.

You need reliable intelligence to target where the gun is located, and then you need to land and blow your way down there... leaving aside the fact that Meson cannon deep-sites are often constructed under top secret conditions, or that you have to contend with the surface defenders.

Also if I'm the other side of the planet, magic or no magic, I have doubts about it's ability to shot through the planets very core and somehow still get at me without me even noticing it's coming.

I don't know it's range, but Mesons go through anything and don't harm what they go through until they decay. So theoretically it CAN shoot through the core, if it has the range.

And besides, what are you gonna do on the other side of the planet? Assuming that section isn't habitable, there go the ICBMs.

[frigidmagi]

You need reliable intelligence to target where the gun is located, and then you need to land and blow your way down there... leaving aside the fact that Meson cannon deep-sites are often constructed under top secret conditions, or that you have to contend with the surface defenders.

Nukes/antimatter weapons have a wonderful habit of not needing excalt target radiuses. Groundburst can go very deep and when you just slam one on top of the other... Or worst comes to worst drop rocks. I saw this nice craetor on the way to ASU, go ahead look up creators and Arizona and see the demensions of that one and realize, it was only 150ft long rock. Just the one.

I don't know it's range, but Mesons go through anything and don't harm what they go through until they decay. So theoretically it CAN shoot through the core, if it has the range

Better have a damn good range we're talking about shooting through a whole planet, and god help your poor sods if the the math is wrong.

And besides, what are you gonna do on the other side of the planet? Assuming that section isn't habitable, there go the ICBMs.

I think you should be asking, what won't I do with a beachhead and safe place on your planet. Also we've broken the FTL barrier but can't have missle defenses? Any invasion fleet I whip out will have satilles, ground and ship based defenses against that. Where's has by this point you're stuck with just ground defenses. I think I have better defenseive set up then you and I'm on your planet.

[Stofsk]

I'll say it here, that this is half-assed scifi scenarioising and verging on a thread hijack, but whatever:

Nukes/antimatter weapons have a wonderful habit of not needing excalt target radiuses. Groundburst can go very deep and when you just slam one on top of the other... Or worst comes to worst drop rocks. I saw this nice craetor on the way to ASU, go ahead look up creators and Arizona and see the demensions of that one and realize, it was only 150ft long rock. Just the one.

That's nice, but you still need a TARGET for those weapons, because I can put those deep-site guns anywhere I want, meanwhile you don't know where the deep-site guns are, and there is likely to be more than one for redundancy's sake, and whoops! They just blew up your command ship, because it's the biggest ship and thus easier to hit.

Meanwhile your incoming bombs will be taken out by laser defences, and other conventional defences will keep the invaders occupied. And even if they're not, you just nuked - or worse, dropped antimatter (!) - on the planet you wanted to invade. So what's the point of invading it?

I don't know it's range, but Mesons go through anything and don't harm what they go through until they decay. So theoretically it CAN shoot through the core, if it has the range

Better have a damn good range we're talking about shooting through a whole planet, and god help your poor sods if the the math is wrong.

Why can't I have multiple deep-site gun emplacements on every quarter - or more - of the globe? You think I just need one?

Assuming my planet is wealthy and has a large population in need of defending, why can't I fund these multiple gun emplacements? Assuming a rebel outpost, I don't NEED to have lots of guns, because all I need is the one to keep my evacuation corridor free of hostiles, so while your marines are busy establishing a beachhead my futuristic al qaeda buddies are packing up and leaving,

I think you should be asking, what won't I do with a beachhead and safe place on your planet. Also we've broken the FTL barrier but can't have missle defenses?

Your missile defence has just blown up thanks to my meson guns, remember?

Your fleet has jumped into the system with FTL and is in the process of invading the planet. It either knows about the deep-site gun emplacement positions, and has special bunker-buster nukes or futuristic equivalents, or it doesn't. If it doesn't, what's it gonna do when shot after shot of highly energetic particles decay inside the starships?

That's ignoring the possibility I have multiple and diverse defence systems such as orbital forts and missile batteries, as well as laser guns to act as a missile defence. Or ships of my own.

Even if it's just the Meson gun by itself, protecting a rebel gurilla base a la the Hoth example, it's still going to chew up the enemy fleet like the Hoth Ion cannon did, but it'll do a better job .

Any invasion fleet I whip out will have satilles, ground and ship based defenses against that.

The invasion fleet has to contend with a lot of defences, not just the Meson guns. And again, what are your marines gonna do when my planet is highly populated and industrialised to warrant complete coverage of the globe with deep-site Meson emplacements? In addition to a defence fleet in orbit, missile platforms and other 'conventional' defences?

If this is a 'rebels on Hoth' scenario, what are your marines doing on the other side of the planet? I'm busy evacuating, and my Meson emplacement will give me the covering fire to get the hell out of there...

Where's has by this point you're stuck with just ground defenses. I think I have better defenseive set up then you and I'm on your planet.

My mistake was saying "I can rely on Meson guns!" which was my attempt at being funny. This is more or less a half-assed scenario anyway, since the original thread topic was concerned over which is better, space-based or ground-based defences, and the answer is "Both!" Relying on one weapon system for defence is foolhardy, so if we're going to be serious (as far as a scifi discussion goes) I wouldn't rely on Meson guns as they'd be my heavy hitters. I'd have missile platforms, lasers to shoot down incoming missiles, warships in orbit, standing army on the surface, COACC aerospace interceptors, this that and the kitchen sink too...

[Stofsk]

Oh and before anyone gets on my butt about the magical properties of Meson guns, there is also a counter to it called a 'Meson screen', which is effectively a forcefield to scatter Meson particles before they can decay inside your ship. Also, warships can mount said guns as well, so the possibility exists that the invasion fleet has these weapons as well.

The important part to remember is knowing yours and the enemy's capabilities, which means intelligence. If you want to invade a planet with multiple deep-site Meson emplacements, you need to know where they are located as well as being able to combat them yourself on equal terms (Meson screens).

[Cynical Cat]

I've walked around the crater frigid mentioned. It's big and very cool.