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Invading Star Systems/Defending Them

RainOfSteel

SOC-14 1K
I've had some thoughts lately about what happens during invasions of strategically important star systems, ones which, for whatever reason, are considered "cannot be lost" locations. I would tend to believe that Capital would likely be first on the list, Depot systems would be next, and other worlds, ones of still high importance, like High Population worlds, would be next.

Most of these worlds will have been under Imperial control for some time, in some cases, for centuries. This provides for plenty of time to install massive layers of defenses.

But first among these, I would think, would be the meson gun. Giant meson guns buried beneath the crust of a planet or moon would be able to fire at orbiting invading vessels with relative impunity. By using gravity generators to prevent densitometer location, and keeping the fusion power plants located far away to prevent neutrino detection, these buried weapons would be quite difficult to locate, maybe even impossible.

Further, it is entirely reasonable to assume that a ground-based weapon system can be built much larger and more powerful than a starship based weapon system, these underground meson guns would, IMO, be much larger and possess much greater range than anything aboard an invading fleet at the same TL.

So, by way of example, in the MTU, the invading Vargr fleets enter Depot/Corridor (after the Corridor Fleets have departed to aid Lucan).
Somewhere between 1000 and 2000 buried giant meson cannons open fire on the invading fleet from well beyond their return-fire range (even should the Vargr somehow have a method of locating those buried meson cannons, the increased range of the oversized weapons prevent them from being fired upon during the initial engagement).
I sort of envision titanic fleet casualties being inflicted, so vast as to render the invading fleet impotent. Anything that did get into orbit would be chopped to bits, anything on the ground would get blown to pieces by, say, indirect strikes from several thousand buried meson gun bays, well capable of striking anywhere on the planet's surface to destroy ground troops.


Even if my idea of over-size increased-range meson cannons doesn't wash, and only type-T meson spinal mounts are considered, I still think that the invading fleet would have little chance of successfully targeting them, hidden as they were. In this case, as well as in the first above, I think an invading fleet would be savaged (and there would be more type-T spinal guns, say somewhere between 4000 and 8000, given that they'd be less expensive than my speculative oversized meson cannons). Even with far fewer guns, say only 500 to 1000, I think that in a few combat turns, an invading fleet would still see significant casualties, especially given the inability of that invading fleet to effect return fire.

Of course, the expense involved means only a few systems are built-up this way, as noted above.


Can anyone think of a way that an invading fleet could somehow survive such a barrage of meson fire? Meson Screens and Needle configurations alone will not help enough, I think. Or should I just pretend that no one would ever think of defending a planet in this manner?


Sincerely,

Chris O.
 
Originally posted by RainOfSteel:

Can anyone think of a way that an invading fleet could somehow survive such a barrage of meson fire? Meson Screens and Needle configurations alone will not help enough, I think. Or should I just pretend that no one would ever think of defending a planet in this manner?


Sincerely,

Chris O.
Chris, the cost of this would be prohibitive except for regional/sector capitals etc.


That being said, the way I might do it is with trickery. One send in decoy ships at
extreme range sending out active transponder signals of larger attack craft. Do
this over and over at different points on the edge of the system. Then pick my
time before sending in the real fleet.Two,using a regularly scheduled liner/merchant
(commandeered by my forces out of system) loaded to the gunnels with commandos
do a ground assault. Three, using spies posing as merchants etc. to locate the defenses
and aid the commandos.

That's not a perfect plan (far from it) but, that's just off the top of my head. The point
being no defense is invulnerable if your willing to take the losses.
 
While I doubt even Capital/Core is defended by thousands of deep meson gun sites, such weapons are the best anti-ship defense any high-tech world can have.

However, deep meson guns aren't that great for picking off small things, like fighters and assault shuttles, so if you =have= to take a planet defended by them you do it the old-fashioned way, on the ground. If you can capture enough of the planet's surface you can reduce the effectiveness of the meson guns by knocking out many of their sensors.

However, that's incredibly expensive, as anyone who's played the old "Invasion:Earth" game can attest, so usually if you're after a high-tech world you just surround them and lay siege to the planet until they surrender.

Treachery is another way to take such a planet, and is a method as old as humanity itself. Getting someone to give the planet to you (or at least betray the defenses) is much cheaper than laying siege to the place for possibly years. I bet the Zhodani are masters of this approach.
 
Drop things from orbit onto military bases and government offices. A planetary ruler may not capitulate if you start destroying population centers, but get his own personal palace and he may think twice.
 
Originally posted by RainOfSteel:
By using gravity generators to prevent densitometer location,
How would this work? The gravity generators would show up as an anomality like a beacon. Better solution: bury the guns deep enough to prevent densitometer detection.

and keeping the fusion power plants located far away to prevent neutrino detection, these buried weapons would be quite difficult to locate, maybe even impossible.
Well, destroy what you can detect, then. No matter how far away the power plant is,

Further, it is entirely reasonable to assume that a ground-based weapon system can be built much larger and more powerful
I dunno. Building a gigantic cave several kilometers underground is probably no smaller an undertaking than building a starship. Additionally, you have to invent some mechanism for turning the guns. Starships do this by moving, which is naturally impossible for an underground gun.
Additionally, there are strong hints that there is a maximum practical size/power for meson guns at a given TL. Starships could theoretically accomodate much larger guns than a Type T, but yet these don't exist.
Furthermore, the range of meson guns does not appear to be tied to their size.

Can anyone think of a way that an invading fleet could somehow survive such a barrage of meson fire?
1. Convince yourself that they have it coming and you really don't need that planet for yourself.
2. Circle target world at a safe distance, destroy all opposing spacecraft and send in myriads of jamming drones.
3. Send in tens of thousands, or even hundreds of thousands of fighters and similar craft.
4. Turn surface area of target world into a wasteland.

Regards,

Tobias
 
Positioning Meson guns on the surface of moons or asteroids won't work. All I have to do as the invader is stand off outside range and kinetic bombard them into rubble. You have to be mobile...Can't let someone stooge around in the outer system at will...They can accel up to fractional C and zip through for a lighting strike, taking out your orbital defenses with missles and KI weapons. You have to interrogate at the fist sign of jump-in. The best time to counter hit is while they are stumbling around right after they come in - slow and confused...
The advantage in Traveller is with defense, even though it seems easier to attack - There is no sure-fire way to mass jump ships into a system with accuracy. What happens when the lead takes 150 hours for their jump, but follow on units take longer, or are displaced and jump in many miles from target...Defense could pick them off one by one. But if they did get a foothold in a system, it would be easy to stand off and throw stuff into the inner system to pick off defenses...

just some thoughts...
-MADDog
 
Originally posted by MADDog:
The advantage in Traveller is with defense, even though it seems easier to attack - There is no sure-fire way to mass jump ships into a system with accuracy.
This can easily be solved if you pick your arrival point far enough from any possible defenses, and allow for a day or so for the fleet to assemble. This will probably ruin surprise, though.

Regards,

Tobias
 
Originally posted by Tobias:
</font><blockquote>quote:</font><hr />Originally posted by MADDog:
The advantage in Traveller is with defense, even though it seems easier to attack - There is no sure-fire way to mass jump ships into a system with accuracy.
This can easily be solved if you pick your arrival point far enough from any possible defenses, and allow for a day or so for the fleet to assemble. This will probably ruin surprise, though.</font>[/QUOTE]Not necessarily. Presumably you'll have scouted the system first? Plot a Jump arrival point that puts you in the 'shadow' of the outermost planet. Largely use 'silent running' as you head in-system. Separately arriving smaller craft are dispatched to take out perimeter warning satellites. It'll still take several hours for transmissions to reach an inner world.

Anton
 
Originally posted by Anton:
Not necessarily. Presumably you'll have scouted the system first? Plot a Jump arrival point that puts you in the 'shadow' of the outermost planet. Largely use 'silent running' as you head in-system. Separately arriving smaller craft are dispatched to take out perimeter warning satellites. It'll still take several hours for transmissions to reach an inner world.
This largely depends on how effective search sensors are IYTU, and how dense the surveillance of the star system is.
If you assume fairly good stealth, and surveillance is not flawless, things could well work as you describe. However, destroying or jamming warning satellites will definitely alert the enemy that something is invading, though not necessarily what.

Regards,

Tobias
 
Ask the French about the value of fixed defenses...

Seriously, any major planet will have AT LEAST one deep-meson gun, buried down at least 50km where it can't be picked up by densitometer. Power comes from the planetary grid in general, thus requiring a prohibitive number of strikes to take out the "power plant". Sensors have to be scattered as well, by necessity.

What does this mean for the attacking party? COMMANDO! Sneak in, destroy the power distribution node that feeds that big grid into the one cave complex, or the commo system feeding in targeting data. You do this while the invasion fleet is in Jumpspace.

Back up plan? Jump into the local Oort cloud and start heading in at full accel. Relativistic cannonballs can't be shot down, if you make them from the right stuff they won't even be DETECTED! Of course, they can't be stopped either, so once the party gets started it's too late to surrender, unless the balls have destruct systems. Destruct systems can be subverted, though, so that's going to be a long-odds bet!
 
Originally posted by Tobias:
Originally posted by RainOfSteel:
By using gravity generators to prevent densitometer location,
How would this work? The gravity generators would show up as an anomality like a beacon. Better solution: bury the guns deep enough to prevent densitometer detection.

and keeping the fusion power plants located far away to prevent neutrino detection, these buried weapons would be quite difficult to locate, maybe even impossible.
Well, destroy what you can detect, then. No matter how far away the power plant is,

Further, it is entirely reasonable to assume that a ground-based weapon system can be built much larger and more powerful
I dunno. Building a gigantic cave several kilometers underground is probably no smaller an undertaking than building a starship. Additionally, you have to invent some mechanism for turning the guns. Starships do this by moving, which is naturally impossible for an underground gun.
Additionally, there are strong hints that there is a maximum practical size/power for meson guns at a given TL. Starships could theoretically accomodate much larger guns than a Type T, but yet these don't exist.
Furthermore, the range of meson guns does not appear to be tied to their size.

Can anyone think of a way that an invading fleet could somehow survive such a barrage of meson fire?
1. Convince yourself that they have it coming and you really don't need that planet for yourself.
2. Circle target world at a safe distance, destroy all opposing spacecraft and send in myriads of jamming drones.
3. Send in tens of thousands, or even hundreds of thousands of fighters and similar craft.
4. Turn surface area of target world into a wasteland.

Regards,

Tobias
A giant hollow spot in the crust, the cyst holding a meson cannon, would, I think, be detectable by a densitometer. If you use a gravity generator, it would be able to _simulate_ density. High quality equipment should be capable of generating a field making the surrounding area seem indistinguishable from ordinary matter. After all, the densitometer is really detecting gravity, right? A purpose-built gravity generator should be able to fool that.

As for actually detecting the power plants, yes, they can be fired on. But in my main assumption, oversize meson cannons fire on the enemy fleet from beyond their return-fire range. In my secondary assumption, the enemy fleet must weather horrible casualties to destroy those generators. Personally, I don't think much would be left of an attacking fleet by the time it was done. (EDIT on 06 April 2011: The power generators also would not be located with the meson guns. They would be somewhere else and be distributed.)

1 Meson Gun buried in the crust is going to cost less than a capital ship, a lot less, given the cost of jump drives. Its going to be several Meson Guns per invading enemy ship, at the least.

Moving an underground gun in not "naturally" impossible. Each cannon is inside a sphere, the sphere may rotate to face in any direction.

Building underground caverns, I thing, would be far easier than today, with fusion gun technology to melt away rock at very high speed and superdense armor to hold it up with well-made arch structures. I don't forsee this as a problem as long as they don't go too far down. Being underground is just a shield against detection, the depth itself not being a defense except against surface nuclear bombardment, which wouldn't be the real threat.


The mass-jamming drone idea. I like that. Hadn't thought of it. It applied to fleet tactics, of course. I wonder what would happen if one Tigress out of eight were equipped with 1500 10-dTon jamming drones and it launched them into a battle. What HG to-hit modification would that give in an ECM/ECCM sort of sense? In an environment where such tactics were used, though, counter tactics would exist. Penetration of jamming would have to exist, otherwise no one would ever hit each other. In one sense, I would imagine a net of densitometers and neutrino detectors would functions as a high-resolution system attempting to defeat enemy mass jamming.

But as for fighters, the second line of defense on these type of no-lose worlds would be several thousand buried meson gun bays. Cheaper than the spinal mounts, they'd be available in even larger numbers. Standard surfance weaponry would be available, too, missing bays, laser turret batteries, and repulsort bays; the buried meson cannons would not be operating alone, they are just the big club that the all-important capital ships would have to face. This weaponry array could target and attack the fighters, the sensor jamming drones, and incoming nuclear missiles.

Hmm, I wonder what the cost of world-spanning Meson Screens and Nuclear Dampers would be? I also can't imagine that some hyper wealthy high-pop world never invested in such giant projects.

As for size not being tied to range . . . okay, I'm an old-time CT person . . . I never actually saw meson ranges (HG was all abstract), but never had any reason to think otherwise. I never did see anything to make me assume the meson gun tables were anything more than a design sequence convenience. Hmm, meson communicators, IIRC, from my old and now vanished Grand Survey (or Grand Census), had variable range depending on size/TL (ok, I admit it, I can't remember). The T20 design lists all the meson spinal mounts as having a range of 75000 kilometers, but I find that to be highly unrealistic. The higher the energy imparted to the mesons, the longer they'd take to decay and the farther they'd go. Although diminishing returns would figure into it, it shouldn't all just cut off at that same distance.
 
Last edited:
Originally posted by MADDog:
Positioning Meson guns on the surface of moons or asteroids won't work. All I have to do as the invader is stand off outside range and kinetic bombard them into rubble. You have to be mobile...Can't let someone stooge around in the outer system at will...They can accel up to fractional C and zip through for a lighting strike, taking out your orbital defenses with missles and KI weapons. You have to interrogate at the fist sign of jump-in. The best time to counter hit is while they are stumbling around right after they come in - slow and confused...
The advantage in Traveller is with defense, even though it seems easier to attack - There is no sure-fire way to mass jump ships into a system with accuracy. What happens when the lead takes 150 hours for their jump, but follow on units take longer, or are displaced and jump in many miles from target...Defense could pick them off one by one. But if they did get a foothold in a system, it would be easy to stand off and throw stuff into the inner system to pick off defenses...

just some thoughts...
-MADDog
I have heard about giant flamewars involving the discussion of accelerating small or large masses up to near C for use in targeting fixed path objects like worlds. I didn't want to bring it up. I can only imagine some kind of very high tech defense systems, probably involving large scale gravity barriers or jump field generators. Counter-fire would be very hard, with random probability influencing firing down at the sub-nano second scale, it's much easier to hit the slow moving target with a near C bullet than to aim a second near C bullet at the first and expect to hit. Maybe a quantum computer driven system could do it, but then, quantum computing concepts make my head hurt.
 
Originally posted by Ben W Bell:
Drop things from orbit onto military bases and government offices. A planetary ruler may not capitulate if you start destroying population centers, but get his own personal palace and he may think twice.
I believe that in the scenario I've outlined that anything large enough to engage in significant orbital bombardment is going to get blown away before it can commit that bombardment.
 
Originally posted by RainOfSteel:
A giant hollow spot in the crust, the cyst holding a meson cannon, would, I think, be detectable by a densitometer. If you use a gravity generator, it would be able to _simulate_ density.
Not when using the densitometer as originally described. Artifical Gravity creates a distinct disturbance for densitometers. They can be grav shielded, however, to prevent this problem.

But in my main assumption, oversize meson cannons fire on the enemy fleet from beyond their return-fire range.
Well, yeah, but this doesn't hold true either. The power generators are immobile targets on a monitored planetary surface, while the ships are mobile targets millions of miles away. I don't even want to drag near-C rocks into this debate, but the attacking fleet can stay well out of any meson gun range and hurl specialized missiles at the planet.
And I repeat: CT meson guns' range does not really depend on size.

Meson Gun buried in the crust is going to cost less than a capital ship, a lot less, given the cost of jump drives. Its going to be several Meson Guns per invanding enemy ship, at the least.
You don't have to risk your jump drives. You just use Battle Riders.

Moving an underground gun in not "naturally" impossible. Each cannon is inside a sphere, the sphere may rotate to face in any direction.
And you're saying that a gigantic moving apparatus buried kilometers underground, wouldn't cost anything? Besides, if Spinal mounts could easily be built as rotating, they wouldn't be spinal mounts.

The mass-jamming drone idea. I like that. Hadn't thought of it. It applied to fleet tactics, of course.
I'd assume this to be a standard tactic in invading a world. It's less useful in open space, though, because spaceships aren't sitting ducks.

But as for fighters, the second line of defense on these type of no-lose worlds would be several thousand buried meson gun bays.
A Meson gun bay has a snowball's chance of hitting a small and agile target such as a fighter. Use a good gunboat instead, and you can just forget the threat altogether.

This weaponry array could target and attack the fighters, the sensor jamming drones, and incoming nuclear missiles.
This is true, but this is also what it boils down to. Of course the invading fleet needs to be able to saturate the conventional defenses.

Hmm, I wonder what the cost of world-spanning Meson Screens and Nuclear Dampers would be?
In case of Meson Screens: Way too much. Just look at how much power a meson screens for a measly ship consumes. Then compute the power cost for a planet. Remember these are based on protected volume.
For nuclear dampers you would need a network of stations around the globe. Since nuclear dampers do not offer complete protection, however, you would still be vulnerable.

I also can't imagine that some hyper wealthy high-pop world never invested in such giant projects.
They are not feasible.

As for size not being tied to range . . . okay, I'm an old-time CT person . . . I never actually saw meson ranges (HG was all abstract), but never had any reason to think otherwise. I never did see anything to make me assume the meson gun tables were anything more than a design sequence convenience.
To-hit-numbers for meson guns go up for a while when you increase power, but reach their optimum fairly soon. This can be easily attributed to the fact that the inherent difficulties in timing meson decay cannot be overcome at some point.

Regards,

Tobias
 
Sounds like siege warfare to me. Impenetrable defenses versus mobile offense.

Why wouldn't you just blockade the system, prevent outgoing/incoming communications, and wait them out? Popular pressure would eventually cause the defenders to try to run or break the blockade, producing the space battle you've already planned for. Once the defender's navy has been defeated, the planet is in even a worse bargaining position.

Yes/No?
 
I don't really have an answer for "how do you conquer/stop the conquest of a planet, but I begin to wonder what type of ships you would do it with. The answer to the first is in the topic "Traveller Equivalent of Carrier Battlegroup," and the answer to the second is undoubtedly in here somewhere.
 
Originally posted by Ran Targas:
Why wouldn't you just blockade the system, prevent outgoing/incoming communications, and wait them out?
For the same reason that you usually want to avoid a siege: time. Laying siege to a planet ties up valuable resources you might need elsewhere. Also consider you can't "starve out" most planets.

IMHO, as soon as the invaders have space supremacy in a system, they can neutralize* an enemy planet pretty much at will, using long-range beam weapons, kinetic kill attacks or good ol' nukes.
Conquering a planet or just destroying its defenses might be a lot more difficult.

Regards,

Tobias

*nice term for laying waste to an entire world and killing billions, eh?
 
@ RainofSteel

Btw, sorry if my last response to you seemed a little snappy, but I was just in a hurry when I posted it.

Regards,

Tobias
 
Originally posted by Tobias:
For the same reason that you usually want to avoid a siege: time. Laying siege to a planet ties up valuable resources you might need elsewhere. Also consider you can't "starve out" most planets.

IMHO, as soon as the invaders have space supremacy in a system, they can neutralize* an enemy planet pretty much at will, using long-range beam weapons, kinetic kill attacks or good ol' nukes.
Conquering a planet or just destroying its defenses might be a lot more difficult.

Regards,

Tobias

*nice term for laying waste to an entire world and killing billions, eh?
[/QUOTE]

Well, the heart of this discussion is how do you conquer a TL15 high-pop planet with elaborate planetary defenses without destroying the ecosphere; IMHO you can't. With TL15 defenses, limited planetary bombardment with kinetic or fission/fusion warheads would ineffective. So you're left with complete sterilization or siege. If you want the planet, you would have to encourage the planet's leadership to concede.

With regards to space supremacy; do you know how big an volume a solar system contains? You might be able to control the traditional jump points but space supremacy throughout the entire system is impossible. Supremacy means complete control over what flies and what dies in the subject area. When U.S. CVBG's talk about air supremacy, it's not over the entire Pacific, it's just around the battlegroup or the objective; roughly an 500mile diameter dome.

Controlling access to the whole system and preventing enemy movement to/from the main planets is beyond the capability of entire sub-sector fleets.
 
Originally posted by Ran Targas:
Well, the heart of this discussion is how do you conquer a TL15 high-pop planet with elaborate planetary defenses without destroying the ecosphere;
That would surely require very large resources and entail serious losses for the attackers.
But then again, you don't have to. If the enemy insists on fighting on, and doesn't surrender after a few warning bombardments, he had it coming.

With TL15 defenses, limited planetary bombardment with kinetic or fission/fusion warheads would ineffective.
I might disagree, depending on what you mean by "limited". There is no conceivable practical means to defend against well-planned kinetic bombardment.

With regards to space supremacy; do you know how big an volume a solar system contains?
You just have to use the good old "points and lines" approach, except you could even do without the "lines" part.
When you establish a wide perimeter around the main world, effectively blockading it and also secure a source of fuel, you're practically set.

Space supremacy in a system means to me that your space forces *could* establish control over any point of their choice in that system.
Naturally, they can't keep enemy forces from jumping in. Having destroyed the opposing fleet elements is a precondition for attacking a world.

Controlling access to the whole system and preventing enemy movement to/from the main planets is beyond the capability of entire sub-sector fleets.
This depends on the system, especially on the quantity of reliable fuel sources.
I think this is the reason that many Imperial depots are located in systems without Gas Giants and with little natural sources of fuel. Control of fuel sources for jumping is of utmost importance for any attacker or counter-attacker.

Regards,

Tobias
 
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