The Role of Ground Forces in Interstellar Warfare

[Marduk]

To pull back to the bigger picture, I'll try summarizing some of my thoughts on ground forces.

1) Ground assets are likely cheaper than space assets.

To be useful, space assets have to have longer range and accuracy than a ground asset. A modern tank gun is extremely accurate over a 1-2 km range. An accuracy of 100,000 nanoradians gives a spread at 2 km of roughly 0.2 m. The same accuracy over a 100 km gives a spread of 10 meters, 1,000 km 100 meters.

An order of magnitude in improved accuracy/range likely implies more than an order of magnitude increase in cost (depending on the exact cost curve).

That's "dumb" ballistic weapons only, of course anyone using those would not use them in a role as long range weapons. Does not apply to guided missiles and other weapons with some sort of guidance and terminal maneuvering.
Also the space forces get their missiles and bombs boosted by gravity well rather than having to spend dV on making them leave it.

2) Holding and controlling territory with air assets alone is very difficult/impossible, space generally increases all those problems: much higher minimum useful accuracy, longer range, shorter time over target, observation difficulties, likely comparatively high upkeep/sustainment costs and thus also high logistical cost, high unit cost which leads to lower number of units available/increased difficulty of replacement, which further makes attrition costs extreme.

Hence space asset heavy "control" would have to be heavy on what space assets do well, as in destroying things.

3) Combined arms is a thing, and I believe would still be a thing in space. For example, dispersion, high mobility, and heavy fortifications are all effective mitigating the effective firepower of space. Heavy dispersion however makes the enemy weaker at resisting ground forces, and some types of cover that may hide a target against distant space targets may be dramatically less effective against surface level scouting, and having to protect against orbital bombardment and infantry/armor dramatically increases the complexity of fortifications and raises the minimum viable scale of a mobile units: it would be quite unpleasant to lose an expensive anti orbital system to a commando with a demolition charge, but adding a IFV with infantry to guard every such platform likely represents a large increase in logistic consumption and makes a larger vehicle group, increasing chance of detection.

Now, some of the immediate counter arguments, and why I think they may be relatively limited.

Anything that protects from orbital bombardment would have to be effectively indistinguishable from protection against superheavy artillery. In conclusion, we are talking about something along the lines of hardened command posts and nuclear shelters *at minimum*, not a fighting position with some berms and trenches.

1) Orbital superiority: The classic argument that who has the high ground wins. That once the space battle is over, the surface might as well surrender due to their compete helplessness. I obviously disagree with this.

a) If both the space and planetary forces are on equal technological footing, they likely have roughly equivalent range and accuracy: if a space weapon can accurately engage a surface target at x range, a surface vehicle likely has comparable range against a space target. While there would be some variations dependent upon the specific technology, for the same tech level I would expect a degree of completeness between space and surface assets, rather than crushing advantage one way or the other.

Besides the weapon scaling, sensors, technological difference, and the gravity well effect.

b) If anything, I expect a degree of superiority to surface assets, due to their grounded nature: easier to hide, less dependent on high tech for basic functionality (a space cruiser may be 10% by mass advanced weapons and 40% advanced engines to maneuver: a space cruiser can just be 10% advanced weapons, so for the same "advanced tech" budget you can equip 3-5 cruisers, built out of cheaper materials because saving every gram is not as critical. Or you can power laser batteries off the general grid and move equipment by truck/train/barge, requiring less tight and exacting weight optimization.

Generally, something along the lines of a defenders advantage. Tactics, doctrine, and details of the tech will swing the specifics, but for relatively equivalent investments space having the decisive advantage on its own seems unlikely to me.

That maneuver ability is absolutely relevant to combat though, especially with how relatively hard it is to create anti starship "area weapons".
Lets say the cruiser is on low orbit and some sort of ground based platform sling identical railgun slugs at each other, and they have 60 seconds to dodge. Not only the ground platform's slugs get slowed by the gravity well, well, what will it do? If it moves like a average MBT, at roughly 60 kph, it may get 1 km away from the impact point. If the shell has some kind of terminal maneuvering or a large nuke, it's fucked.
The space cruiser meanwhile has options. It can do a calm .2 g maneuver. It's gonna be missed by over 3km, in space that's enough to make nuke ineffective, and it will take considerable sensors and terminal maneuvering to correct for it (guidance in atmosphere can be simpler, using fins, rather than full on rockets). A more ambitions emergency maneuver of 1.5g will put it 27km off course.
Or it can just save dV and instead try to use its point defense weapons to throw the slug off course. Especially if it has laser PD. If 30 seconds before impact it can change the slug's course by mere 25 m/s in any way by burn-off, that means it will miss by half a kilometer, not to mention damage to any more advanced warheads, guidance or sensor systems the slug may contain.

c) Even with complete orbital superiority, that seems likely to push enemy ground forces directly to a guerilla campaign, which will require a ground forces anyways. If Orbitals can't be contested, that suggests the correct response is to not contest them: Don't defend what can't be defended, instead focus on force preservation and try to stretch the enemy thin. If the enemy for example wanted to conquer Texas for oil production because the broader campaign their fighting requires oil, don't seriously contest the conquest of Texas, certainly not to the degree of overly sacrificing forces for it, but let them go in, preserve your own people and infrastructure as much as you can, and pull back to the limit of their logistical ability.

Getting a perimeter around those big oil producers around Texas is about a 5,000 km perimeter, with an interior of roughly 2 million km^2. If they're deploying an army of 1-2 million men, that's likely something like the limit if you can maintain an army in being capable of at least threatening and harassing that perimeter (with the enemy having orbital superiority, decisive breakthroughs are probably less likely, and just highly risky). You can keep the enemy control limited and in a position to be atritted, while preserving a lot of your people and infrastructure.

Exactly how this is carried out is of course setting dependent, and probably more viable the more politically complex the situation is. Invading Space Afghanistan is complicated if the Taliban can set up a government in exile in space Pakistan a system over, from which they can lobby other powers and smuggle weapons and general support to the resistance. Even more complicated if the space Pakistan is in the same system, or on the same planet . . .

That sort of matter gets generally dictated by political\strategic impositions above all. If it's so important it warrants a space invasion, you may well have the space invaders be willing to cover a 100 km belt around the strategic location with autonomous killbots and non-decaying nerve gas jelly spray. That way no one without power armor, aircraft or an armored vehicle will be crossing it, and they won't be crossing it easily or quietly then.

d) Combined arms I think does make the forces more effective: Space and ground forces are likely more effective together than each alone. This is important in any resource constrained situation: If you can afford to just have space cruisers zapping bunkers as identified for 10 years, then you don't need to bother. But if you have senators questioning the progress of the campaign compared to its expense? Or your in a situation where winning in the orbital of this planet doesn't mean the enemy fleet is destroyed: maybe the enemy Admiral could also do the math and knew his chance of victory was low, so gave up the orbital without a fight and withdrew to some asteroid naval fortresses to also carry out space guerilla war/wait for a favorable opportunity.

This mean you want to secure the planet more thoroughly, because if you do weaken the space force to chase the enemy fleet or move onto another target, if there are significant reserves on the planet, they might be able to inflict serious casualties on the garrison force, or if the enemy is able to move a relief space force, your ships will be caught between the planets firepower and the relief forces.

If there is any chance of space relief force, the blocking fleet would do better to intercept it in high orbit or deep space, where any but largest, longest ranged strategic weapons of the defenders, for some reason never used earlier, would be relevant.

2) Transporting is expensive in space, and an invasion force is too heavy.

Invading a planet, especially a heavily populated one, is a huge undertaking, and with current space costs completely infeasible. I have two main counterpoints:

a) Its not necessarily all that much in the grand scheme of things. Lets say 1 million man force, equipped with 10 tons of equipment per man, a fairly heavy level of supply, so 10 million tons. That is quite a lot of mass. However, in comparison the US navy has roughly 4.6 million tons of displacement, and would be a pretty small fleet compared to world conquering. Earth's total civilian fleet transport capacity in 2022 had roughly 2.2 billion tons of cargo capacity. If the future space empire had as much space logistical capacity as we currently have navally on earth, and those craft only made 1 trip a year, moving 1 million man army would represent 0.45% of the merchant marine capacity. If they're averaging monthly trips, 2.2 billion tons of cargo represents the ability to move 26.4 billion tons per year.

In that case, moving a force to invade earth at the optimal occupation rate of 1 soldier per 40, so for our 8 billion man planet a force of 200 million men, with 10 tons of equipment per soldier for 2 billion tons transported, represents some 7.6% of cargo capacity. Not a trivial ask, but not a crippling one either. Maybe to appease the shipping companies the burden can be lowered by determining conquering earth is a 4 year campaign, not a 1 year campaign, so they only need to deliver 1 million men a week to the surface, and the civilian fleet only needs to commit 1.9% of their annual output to the campaign.

And all cost benefit analysis has to of course be "compared to what?" Maintaining a fleet in combat is also unlikely to be a logistically cheap operation either: Say your fleet had a loaded mass of 10 million tons, "only" roughly twice America's navy weight. Spaceships are quite fuel hogs under almost all plausible tech, but lets say they only consume 1% of their mass per day of operation in fuel and other consumables on average. That still means the fleet is consuming 100,000 tons of material per day. In a year of operation that's a good 36.5 million tons.

A ground campaign is quite logistically intensive, but an orbital campaign is also likely to be quite logistically intensive. And forces on a planet can "live off the land" to a degree ships in the void of space can't. Though obviously securing other, easier targets to give some ability to live off the land to the battleships would be quite useful too.

Of course a wannabe space empire would need to have more logistical capability than a 7-8 billion single-planetary civilization, nevermind a single 340 million superpower in it, especially before it tries to go around conquering highly developed and defended planets (a small mining\research colony with 100k people spread through few hundred small outposts all over the planet will obviously be far easier).
40k, for example, has individual transport ships with capacity measured in megatons. Anyone interested and remotely capable of doing full scale planetary invasions would need to have this kind of logistical capability, as in at least a small fleet of single digit kilometer scale transports.

3) Landing is overly dangerous and difficult: between the effectiveness of defense, the specialized vehicles, and other concerns, actually carrying out a landing against a defended planet is hideously expensive and unlikely to suceed: the last 300 km (or 300,000km, depending on where the defensive envelop starts), is a killing zone you can't plausibly land an invasion force through in any condition to fight.

This is the issue I am the least confident in, and I can see the logic of it. I still think ground troops can make through, in sufficient numbers sufficiently in tact, but also see there are some plausible tech assumptions where this is not the case. I think its less likely, but can't certainly rule it out.

This last one may be worth further thought and clarification, but this is long enough as it is. Really meant to get something more bullet point out than this turned into. Something for another day.

Yeah, against heavy defenses, it's not really doable without negating them somehow, or willingness to sacrifice ridiculous amounts of forces. The only option really is to copy the naval landing doctrine at a greater scale, and carpet nuke or otherwise clear a roughly continent sized landing zone of defenders so that craft that get to lower altitudes get horizontal cover from the defender's sensors and LoS weapons and aren't threatened by the more common, shorter ranged ones, while orbital assets suppress the nearby longer ranged ones with strategic weapons too.

 

[Husky_Khan]

I'd just like to point out with a strict literal reading of the title of this thread, the topic has been artificially limited to ground forces responding to orbital or space based attackers.

We never explored the use of ground forces IN space (ie interstellar) warfare.

Well not technically in space. Those space horses would need spacesuits and special space horseshoes to conduct this charge in space.

But you get the idea.

 

[ATP]

I'd just like to point out with a strict literal reading of the title of this thread, the topic has been artificially limited to ground forces responding to orbital or space based attackers.

We never explored the use of ground forces IN space (ie interstellar) warfare.

Well not technically in space. Those space horses would need spacesuits and special space horseshoes to conduct this charge in space.

But you get the idea.

What movie it is?
And,i think,that we could have two times of ground forces:
1.Elites for taking sometching important intact
2.Relatiwely well-trained militias to keep your less important stuff safe.Good enough to wipe out usual pirates.

 

[Husky_Khan]

What movie it is?
And,i think,that we could have two times of ground forces:
1.Elites for taking sometching important intact
2.Relatiwely well-trained militias to keep your less important stuff safe.Good enough to wipe out usual pirates.

The movie is called Rise of Skywalker. Some sort of Star Wars fan film with a huge budget. You can tell they really liked the material but they got too caught up injecting their own original characters and stuff into the movies and while some of it was neat, overall it kind of detracted from the quality. And it has the plot consistency/coherency of a homebrewed Star Wars RPG campaign because you know they didn't write any of their plot out ahead of time so it got really bad midway through the fanfilm trilogy.

 

[ATP]

The movie is called Rise of Skywalker. Some sort of Star Wars fan film with a huge budget. You can tell they really liked the material but they got too caught up injecting their own original characters and stuff into the movies and while some of it was neat, overall it kind of detracted from the quality. And it has the plot consistency/coherency of a homebrewed Star Wars RPG campaign because you know they didn't write any of their plot out ahead of time so it got really bad midway through the fanfilm trilogy.

Well,who need plot,when we have fans and Force on our side ?

 

[Zyobot]

Well,who need plot,when we have fans and Force on our side ?

Should probably clarify that Husky’s being facetious, since he likes to joke around and mess with people.

He’s right about the title and that it’s a Star Wars movie, though. Unfortunately, it’s Disney Star Wars, which really does come across as more of an idealistic fan film (despite being Disney Canon).

 

[JagerIV]

That's "dumb" ballistic weapons only, of course anyone using those would not use them in a role as long range weapons. Does not apply to guided missiles and other weapons with some sort of guidance and terminal maneuvering.
Also the space forces get their missiles and bombs boosted by gravity well rather than having to spend dV on making them leave it.

Are you suggesting guided weapons are not more expensive than unguided weapons? Otherwise, my general point that more range and accuracy equals more cost is true.

Now, in practice the upward sloping cost curve may look more like a step cost than a continuous upward slope, with cost being fairly equal over a set range until a new bit of equipment/technology is needed, and you have a large jump in cost.

Or, more specifically, you would have your settings overall cost curve, with the broader "optimal" range as your tech economy allows, made up of the various u cost curves of the various available sub technologies of their optimal abilities.

But, while obviously a 10 fold increase in range being a 10 fold increase in cost is obviously not going to be an exact relationship, the direction of the relationship is likely correct.

Hence space asset heavy "control" would have to be heavy on what space assets do well, as in destroying things.

Hm, space assets can destroy things. Its not so certain it will do it "well". Depends exactly what we mean.

Anything that protects from orbital bombardment would have to be effectively indistinguishable from protection against superheavy artillery. In conclusion, we are talking about something along the lines of hardened command posts and nuclear shelters *at minimum*, not a fighting position with some berms and trenches.

Which is my point: anti-orbital bombardment positions are not fighting positions, and thus not well suited to countering enemy forces securing the surface: Cheyenne Mountain Complex may be quite survivable against general bombardment, but is not well set up to fight off a company, and that company can likely totally lock down the facility.

A formation optimized to survive orbital bombardment is likely radically different than a formation optimized to fight ground forces. Forcing the enemy to compromise against one or the other threat either leaves them more vulnerable to one threat, or both.

Besides the weapon scaling, sensors, technological difference, and the gravity well effect.

Well, weapon scaling and sensors are likely in favor of the ground, not mobile spacecraft, technological difference doesn't necessarily have to be in favor of the space force, and quite likely the space force needs a higher tech level to be effective than the ground forces. Gravity well effect gives some advantage to space, but I'm not sure its actually all that much, and orbitals are major disadvantage to the maneuverability of spacecraft.

That maneuver ability is absolutely relevant to combat though, especially with how relatively hard it is to create anti starship "area weapons".
Lets say the cruiser is on low orbit and some sort of ground based platform sling identical railgun slugs at each other, and they have 60 seconds to dodge. Not only the ground platform's slugs get slowed by the gravity well, well, what will it do? If it moves like a average MBT, at roughly 60 kph, it may get 1 km away from the impact point. If the shell has some kind of terminal maneuvering or a large nuke, it's fucked.
The space cruiser meanwhile has options. It can do a calm .2 g maneuver. It's gonna be missed by over 3km, in space that's enough to make nuke ineffective, and it will take considerable sensors and terminal maneuvering to correct for it (guidance in atmosphere can be simpler, using fins, rather than full on rockets). A more ambitions emergency maneuver of 1.5g will put it 27km off course.
Or it can just save dV and instead try to use its point defense weapons to throw the slug off course. Especially if it has laser PD. If 30 seconds before impact it can change the slug's course by mere 25 m/s in any way by burn-off, that means it will miss by half a kilometer, not to mention damage to any more advanced warheads, guidance or sensor systems the slug may contain.

This gets into some of the issues of the different trade offs of the actual math: 60 seconds suggests fairly close for artillery. Lets go for 3 km/s velocity muzzle velocity, a bit higher than the navy railgun project which theoretically got to about 150 km up with its ground attack arc, and could likely go higher in a dedicated anti-orbital role. A target at 150 km is theoretically reached by a 3 km/s muzzle velocity reaches a target some 2-3 minutes. A target going some 8 km/s thus must be shot at 1,200 km out.

Shooting straight down at 3 km/s going 8 km/s from an altitude of 150 km means you need to fire 50 seconds before impact assuming no downward velocity loss, and thus some 400 km out. This does theoretically give an advantage to the orbital, but this is comparing a round with drag vs one without, so not quite apple to apple. A surface target can shoot to the left or right without problem too, while firing off orbit will eat up more of the rounds potential velocity. If the round is coming down at high speed, you would also have a plasma layer in front of the projectile, making guidance more difficult. Loss of velocity may allow a closer firing, but likely extend time to target.

0.2 g or 1.5 g for 60 seconds are actually both quite substantial burns, roughly 118 m/s and 883 m/s respectively. To me these generally imply high thrust low efficiency engines. If we had a 100 ton craft with 10 km/s exhaust velocity, the engine output needed is on the order of 2-15 GW thrusters. Maybe a 10 km/s overall vehicle delta v, 6 km/s for transport to and from, so for 4 km/s maneuverability budget, this is something between 3%-22% of budget, meaning the number of dodges is limited there. And of course the surface has point defense too.

Big deep topic though, so I'll move on to the other topics for now.

That sort of matter gets generally dictated by political\strategic impositions above all. If it's so important it warrants a space invasion, you may well have the space invaders be willing to cover a 100 km belt around the strategic location with autonomous killbots and non-decaying nerve gas jelly spray. That way no one without power armor, aircraft or an armored vehicle will be crossing it, and they won't be crossing it easily or quietly then.

You seem to be suggesting an even more/equally costly option, so I'm not sure if this is a particular counter argument.

If there is any chance of space relief force, the blocking fleet would do better to intercept it in high orbit or deep space, where any but largest, longest ranged strategic weapons of the defenders, for some reason never used earlier, would be relevant.

Hm, depends. Deep space has its own downsides. Fighting close to your supply lines and at the max of the enemy is a potentially large advantage, andYour then leaving your forces on the planet more vulnerable too as well.

Of course a wannabe space empire would need to have more logistical capability than a 7-8 billion single-planetary civilization, nevermind a single 340 million superpower in it, especially before it tries to go around conquering highly developed and defended planets (a small mining\research colony with 100k people spread through few hundred small outposts all over the planet will obviously be far easier).
40k, for example, has individual transport ships with capacity measured in megatons. Anyone interested and remotely capable of doing full scale planetary invasions would need to have this kind of logistical capability, as in at least a small fleet of single digit kilometer scale transports.

It worth mentioning though, because its often a point I see. If you don't have a disagreement however I'll move on.

Yeah, against heavy defenses, it's not really doable without negating them somehow, or willingness to sacrifice ridiculous amounts of forces. The only option really is to copy the naval landing doctrine at a greater scale, and carpet nuke or otherwise clear a roughly continent sized landing zone of defenders so that craft that get to lower altitudes get horizontal cover from the defender's sensors and LoS weapons and aren't threatened by the more common, shorter ranged ones, while orbital assets suppress the nearby longer ranged ones with strategic weapons too.

I'm generally less convinced of the carpet nuke continent theory, not particularly seeing it. In fact its generally counter productive. Planets are big, and accurate long range fires get difficult. I'm generally a skeptic of easy extreme range fires. Since long range accurate fires are likely to be more expensive than shorter range weaponry, as well as tend larger and thus harder to hide/more logistically burdensome, they are likely relatively few.

 

[Marduk]

Are you suggesting guided weapons are not more expensive than unguided weapons? Otherwise, my general point that more range and accuracy equals more cost is true.

Now, in practice the upward sloping cost curve may look more like a step cost than a continuous upward slope, with cost being fairly equal over a set range until a new bit of equipment/technology is needed, and you have a large jump in cost.

Or, more specifically, you would have your settings overall cost curve, with the broader "optimal" range as your tech economy allows, made up of the various u cost curves of the various available sub technologies of their optimal abilities.

But, while obviously a 10 fold increase in range being a 10 fold increase in cost is obviously not going to be an exact relationship, the direction of the relationship is likely correct.



Hm, space assets can destroy things. Its not so certain it will do it "well". Depends exactly what we mean.

Do not get yourself locked into purely theoretical comparisons that are easily broken by real developments in weapons. Some concepts really step out of such assumptions really badly - say, a kamikaze drone can be as accurate as a Javelin, at 50-100 times the range, yet cost half as much.
In military use both accuracy and range in some context have to be replaced by "effective range" and "effective accuracy" which can vary greatly depending on intended target. Say, a 155mm HEFRAG artillery's effective accuracy against an infantry platoon marching in the open is very different from its effective accuracy against a MBT, as in it takes far more shells to neutralize one than the other, and in turn it can even get to a point where a precision munition, despite higher individual cost, can take down a small, hard target for less cost than a crapload of cheap munitions.

Which is my point: anti-orbital bombardment positions are not fighting positions, and thus not well suited to countering enemy forces securing the surface: Cheyenne Mountain Complex may be quite survivable against general bombardment, but is not well set up to fight off a company, and that company can likely totally lock down the facility.

Can lock it down, but not destroy it. A place like this has massive importance to countering enemy invasion, as a place like this can provide secure supply, rest and command facilities for the forces who are securing the surface. Without such, the defense force can be degraded into little more than guerillas with some orbital bombardment and time.

A formation optimized to survive orbital bombardment is likely radically different than a formation optimized to fight ground forces. Forcing the enemy to compromise against one or the other threat either leaves them more vulnerable to one threat, or both.

Depends on a lot of assumptions. For one a formation reasonably resistant to orbital bombardment is going to also be highly resistant to more conventional artillery, and that's a big deal.

Well, weapon scaling and sensors are likely in favor of the ground, not mobile spacecraft, technological difference doesn't necessarily have to be in favor of the space force, and quite likely the space force needs a higher tech level to be effective than the ground forces. Gravity well effect gives some advantage to space, but I'm not sure its actually all that much, and orbitals are major disadvantage to the maneuverability of spacecraft.

Depends on tech assumptions badly. The kind of low sci-fi you like to assume is questionable for the very feasibility of large scale planetary invasion at all. On the other hand... Spacecraft can maneuver hard, and "area weapons" in space are very tricky to do.
What maneuverability restrictions do apply to spacecraft, also apply to munitions meant to target and intercept them.
Meanwhile, if you fire something with megaton level firepower at a ground target with few minute's warning, unless it's either very heavily armored, deep underground or moves at least few kilometers per minute (which means Bolo\Titan style ground vehicles, aircraft, submarines, or more normal ground forces raiding from specialized bunker complexes), it's deadso. And that's with just a basic guidance system aimed at a static point on the planet, rather than one actually capable of tracking a mobile target.

This gets into some of the issues of the different trade offs of the actual math: 60 seconds suggests fairly close for artillery. Lets go for 3 km/s velocity muzzle velocity, a bit higher than the navy railgun project which theoretically got to about 150 km up with its ground attack arc, and could likely go higher in a dedicated anti-orbital role. A target at 150 km is theoretically reached by a 3 km/s muzzle velocity reaches a target some 2-3 minutes. A target going some 8 km/s thus must be shot at 1,200 km out.

Shooting straight down at 3 km/s going 8 km/s from an altitude of 150 km means you need to fire 50 seconds before impact assuming no downward velocity loss, and thus some 400 km out. This does theoretically give an advantage to the orbital, but this is comparing a round with drag vs one without, so not quite apple to apple. A surface target can shoot to the left or right without problem too, while firing off orbit will eat up more of the rounds potential velocity. If the round is coming down at high speed, you would also have a plasma layer in front of the projectile, making guidance more difficult. Loss of velocity may allow a closer firing, but likely extend time to target.

0.2 g or 1.5 g for 60 seconds are actually both quite substantial burns, roughly 118 m/s and 883 m/s respectively. To me these generally imply high thrust low efficiency engines. If we had a 100 ton craft with 10 km/s exhaust velocity, the engine output needed is on the order of 2-15 GW thrusters. Maybe a 10 km/s overall vehicle delta v, 6 km/s for transport to and from, so for 4 km/s maneuverability budget, this is something between 3%-22% of budget, meaning the number of dodges is limited there. And of course the surface has point defense too.

Big deep topic though, so I'll move on to the other topics for now.

What you are doing here is the equivalent of proving that a fleet of viking longships lacks the logistical capability to support D-Day, how are they even going to transport the tanks?

If your top of the line space frigates, destroyers and cruisers have dV budget of 10 km\s or anything even remotely in that area, you're not invading planets, you are happy about being able to colonize most of the planets over in the same solar system. Even in Terra Invicta, if your ships have that kind of dV budget for a battle, you are in early-mid game, and you struggle to invade small outposts if they aren't very close.

You seem to be suggesting an even more/equally costly option, so I'm not sure if this is a particular counter argument.

Space invasions are expensive by definition. Failed space invasions are equally expensive and have terrible cost-benefit ratio on top of that.
Also trained and equipped space marines are probably way more expensive than nerve gas anyway.

Hm, depends. Deep space has its own downsides. Fighting close to your supply lines and at the max of the enemy is a potentially large advantage, andYour then leaving your forces on the planet more vulnerable too as well.

The invasion support\transport ships not being in effective range of enemy warships is worth it.

It worth mentioning though, because its often a point I see. If you don't have a disagreement however I'll move on.



I'm generally less convinced of the carpet nuke continent theory, not particularly seeing it. In fact its generally counter productive. Planets are big, and accurate long range fires get difficult. I'm generally a skeptic of easy extreme range fires. Since long range accurate fires are likely to be more expensive than shorter range weaponry, as well as tend larger and thus harder to hide/more logistically burdensome, they are likely relatively few.

Especially in space to ground, range adds very little to weapon cost. Whether a reentry vehicle was put on course to atmosphere by a missile carrier from a 300km or 3000 km orbit makes no difference for its cost. It's also going to use exactly the same targeting systems. You are trying to import classic artillery paradigms to orbital warfare, even though they don't even upscale well to ground to ground weapons (suicide drones and cruise missiles are sometimes cheaper, longer ranged and more accurate than SRBMs for example).
So, for the purposes of "clearing out a landing zone" you may need something along the lines of at least medium to large sized modern nuclear arsenal. Probably mounted on something similar to SLBMs, though due to the different dynamics (going down, not up) and better technology the missiles would be somewhat smaller. We're talking good few hundreds of highly capable, smart missile buses with multiple warheads, guidance systems, decoys, and some maneuvering ability, each weighting around 10-20 tons. Basically need around 10,000 tons in missile cargo for a good shot. Might need a bunch of these for larger zone or better defenses. However, 10 kilotons, or even 50 kilotons, accounting for some launcher hardware and few reload sets, is not much in the context of logistics of a planetary invasion, it's still probably less than a mechanized division with a few weeks worth of supplies, obviously you would need a whole lot more divisions than that to invade a mid sized country, nevermind a whole planet, probably supplies for more than few weeks too.

 

[JagerIV]

Do not get yourself locked into purely theoretical comparisons that are easily broken by real developments in weapons. Some concepts really step out of such assumptions really badly - say, a kamikaze drone can be as accurate as a Javelin, at 50-100 times the range, yet cost half as much.

In military use both accuracy and range in some context have to be replaced by "effective range" and "effective accuracy" which can vary greatly depending on intended target. Say, a 155mm HEFRAG artillery's effective accuracy against an infantry platoon marching in the open is very different from its effective accuracy against a MBT, as in it takes far more shells to neutralize one than the other, and in turn it can even get to a point where a precision munition, despite higher individual cost, can take down a small, hard target for less cost than a crapload of cheap munitions. [1]


Can lock it down, but not destroy it. A place like this has massive importance to countering enemy invasion, as a place like this can provide secure supply, rest and command facilities for the forces who are securing the surface. Without such, the defense force can be degraded into little more than guerillas with some orbital bombardment and time.

Depends on a lot of assumptions. For one a formation reasonably resistant to orbital bombardment is going to also be highly resistant to more conventional artillery, and that's a big deal. [2]

Depends on tech assumptions badly. The kind of low sci-fi you like to assume is questionable for the very feasibility of large scale planetary invasion at all. On the other hand... Spacecraft can maneuver hard, and "area weapons" in space are very tricky to do.
What maneuverability restrictions do apply to spacecraft, also apply to munitions meant to target and intercept them.
Meanwhile, if you fire something with megaton level firepower at a ground target with few minute's warning, unless it's either very heavily armored, deep underground or moves at least few kilometers per minute (which means Bolo\Titan style ground vehicles, aircraft, submarines, or more normal ground forces raiding from specialized bunker complexes), it's deadso. And that's with just a basic guidance system aimed at a static point on the planet, rather than one actually capable of tracking a mobile target. [3]


What you are doing here is the equivalent of proving that a fleet of viking longships lacks the logistical capability to support D-Day, how are they even going to transport the tanks?

If your top of the line space frigates, destroyers and cruisers have dV budget of 10 km\s or anything even remotely in that area, you're not invading planets, you are happy about being able to colonize most of the planets over in the same solar system. Even in Terra Invicta, if your ships have that kind of dV budget for a battle, you are in early-mid game, and you struggle to invade small outposts if they aren't very close. [4]


Space invasions are expensive by definition. Failed space invasions are equally expensive and have terrible cost-benefit ratio on top of that.
Also trained and equipped space marines are probably way more expensive than nerve gas anyway.

The invasion support\transport ships not being in effective range of enemy warships is worth it. [5]

Especially in space to ground, range adds very little to weapon cost. Whether a reentry vehicle was put on course to atmosphere by a missile carrier from a 300km or 3000 km orbit makes no difference for its cost. It's also going to use exactly the same targeting systems. You are trying to import classic artillery paradigms to orbital warfare, even though they don't even upscale well to ground to ground weapons (suicide drones and cruise missiles are sometimes cheaper, longer ranged and more accurate than SRBMs for example).
So, for the purposes of "clearing out a landing zone" you may need something along the lines of at least medium to large sized modern nuclear arsenal. Probably mounted on something similar to SLBMs, though due to the different dynamics (going down, not up) and better technology the missiles would be somewhat smaller. We're talking good few hundreds of highly capable, smart missile buses with multiple warheads, guidance systems, decoys, and some maneuvering ability, each weighting around 10-20 tons. Basically need around 10,000 tons in missile cargo for a good shot. Might need a bunch of these for larger zone or better defenses. However, 10 kilotons, or even 50 kilotons, accounting for some launcher hardware and few reload sets, is not much in the context of logistics of a planetary invasion, it's still probably less than a mechanized division with a few weeks worth of supplies, obviously you would need a whole lot more divisions than that to invade a mid sized country, nevermind a whole planet, probably supplies for more than few weeks too. [6]

1] Your comparing different tech, to achieve different goals, so I don't find it particularly persuasive. I figured effective was implied, but if you insist on increased pedantic, sure, take this as a clarification: by range and accuracy, I mean range and accuracy actually achievable against your enemy.

2] Lock down in many situations is equivalent to destroy. We can focus on this argument later.

3] Eh, sure, if your throwing megaton weapons against random targets, you destroy a lot. Maybe a nuke per tank is even a reasonable trade by your theory.

4] Top of the line would likely have higher delta v, and lower acceleration. Space forces tend to have quite strong trade offs between exhaust velocity and acceleration.

5] I guess if you want to switch the assumption from peer engagement to fighting helpless natives, sure.

6] Ah, gotcha, the goal is just genocide, got it.

 

[Marduk]

1] Your comparing different tech, to achieve different goals, so I don't find it particularly persuasive. I figured effective was implied, but if you insist on increased pedantic, sure, take this as a clarification: by range and accuracy, I mean range and accuracy actually achievable against your enemy.

Again, many variables depending on target, warhead, delivery method, guidance system, there is no simple relationship there.

2] Lock down in many situations is equivalent to destroy. We can focus on this argument later.

Still, without it, other forces are easy to neutralize. Bunkers or something equivalent would be absolutely necessary for fighting orbital bombardment capable enemy.

3] Eh, sure, if your throwing megaton weapons against random targets, you destroy a lot. Maybe a nuke per tank is even a reasonable trade by your theory.

Close enough. A few mechanized platoons or a decent SAM battery already would equal the value of one warhead, and a big warhead can catch a lot more in its blast radius.

4] Top of the line would likely have higher delta v, and lower acceleration. Space forces tend to have quite strong trade offs between exhaust velocity and acceleration.

Again, with low tech assumptions. If you are invading other planets, presumably in other star systems, chances are you aren't reliant on low powered ion drives that can pull off a handful of miligee's. Bringing ships like that to a planetary invasion is like bringing galleons along to D-Day. Little use, and probably gonna die.

5] I guess if you want to switch the assumption from peer engagement to fighting helpless natives, sure.

No, it is a matter of strategy. If you fail that, the enemy fleet, even a small one, may dump its missiles in the direction of your invasion transports and scram. If the vulnerable transports take significant losses, your invasion can no longer succeed, and considering the fact that it is there, you weren't interested in just flattening the place from orbit, so you are in a bind.
The same principle applies to naval and air warfare of both WW2 and modern times. If the defender's large combat craft formations have an option to fire at your transports instead of your combat craft, you screwed up, because they probably will, and it will probably cripple your invasion force before the ground battle even begins. As such, it would generally be important to intercept them at a safe distance.

6] Ah, gotcha, the goal is just genocide, got it.

Only by NGO standards. Was Hiroshima a genocide? Was Stalingrad a genocide? On the scale of planetary invasion, orbital firepower and peer conflict, a significant amount of collateral damage may not be avoidable, especially with a truly peer opponent who is prepared and has a developed planet with a population in billions at disposal.

 

[JagerIV]

Response to the last bit was probably overly glib.

It is however seeming to double down on the 50s idea that nuclear weapons makes war obsolete, which is not the case. If your goal is to just genocide with no limits, then just lots of nukes is an option. We have nearly 80 years of evidence however on how this is not the general case.

Nukes to destroy tuck launcher is a trade, but I'm not sure a reasonable trade. Nuke to destroy an area that might have a truck launcher, killing hundreds to thousands of people on some small probability of inflicting a casualty is even more questionable, pre-emtively destroying whatever it is your trying to capture.

Nukes also make further ground operations more difficult as well. I don't think you as the attacker necessarily want to start out with mass nuking. That option exists, but it seems more profitable to use that in the negotiation of the combat, not part of the general combat. You don't have mutually assured destruction, at least tactically, but you as the attacker prefer not to be nuked too.

Your example also somewhat cheats by pre-supposing the missile carrier, which is a larger potential cost. Like suggesting there's no cost difference between a sidewinder shooting 10 km or one shooting 500 km away from base, ignoring the cost of the $20 million dollar fighter to carry the missile that far, or the cost of the early warning radar needed to find and track a target from that far away.

The direct costs to a 300 km vs 3,000 km range missile might be relatively small: 10x as large batteries for example. Keeping it effective at that range gets more tricky: you either need, I think its roughly 10x as strong sensors or comm systems for an equivalent effectiveness. This is a potentially large increase in minimum sensor package size, depending on that exact scaling.

Your firing ship needs a better sensor package too, in order to line up effectively the longer range shot, growing the capabilities needed on your targeting platform too.

Effectiveness rears its head again too: closing at, say 5 km/s gives your target 60 seconds of warning at 300 km. Like you said, at 60 km/h (approx. 15 m/s) that lets a target move 900 m, which would put the target within the radiation lethal radius of a 10 kton bomb, assuming nukes. This suggests very high likelihood of a kill, even if the enemy is completely prepared. If the enemy is not immediately aware and takes 30 seconds to react, they can only move 450 m/s, meaning you could get roughly the same kill probability (assuming perfect nuke accuracy) with a kiloton or less nuke.

Firing from 3,000 km however closing at 5 km/s gives 600 seconds of warning. That same target now can move 9 km with perfect awareness. You now want a 10 or so MT bomb to have sufficient blast range. Or, against a 100 kt bomb, the vehicle can take 300 seconds, some 5 minutes, to become aware they're targeted and react, and still possibly move out of the kill zone.

So, to preserve effectiveness over range requires a larger warhead, larger sensor pack, with more batteries, all maybe 10x as large warhead, giving you a 10x overall missile scale. But, you potentially need more delta v, through a mixture of more demanding orbital maneuvers and a desire to close faster. Bumping up from, say 3 km/s chem missile to 5 km/s, 3 km/s exhaust velocity increases the needed mass ratio from 3 to 6, so your actual missile scaling goes 20x larger.

So, the above gives you likely a more than 10x increase in cost for preserving effectiveness, which you are correct is the more correct metric to be discussing. effectiveness more or less go hand in hand when discussing range and accuracy for lasers or unguided, which is what I was thinking of when making the initial comment, but using the correct term of effectiveness, which range and accuracy are metrics, I'm not sure just because a weapon is guided its immune to the more range = more cost assumption.

 

[JagerIV]

Again, many variables depending on target, warhead, delivery method, guidance system, there is no simple relationship there. [1]

Still, without it, other forces are easy to neutralize. Bunkers or something equivalent would be absolutely necessary for fighting orbital bombardment capable enemy.

Close enough. A few mechanized platoons or a decent SAM battery already would equal the value of one warhead, and a big warhead can catch a lot more in its blast radius.

Again, with low tech assumptions. If you are invading other planets, presumably in other star systems, chances are you aren't reliant on low powered ion drives that can pull off a handful of miligee's. Bringing ships like that to a planetary invasion is like bringing galleons along to D-Day. Little use, and probably gonna die.

No, it is a matter of strategy. If you fail that, the enemy fleet, even a small one, may dump its missiles in the direction of your invasion transports and scram. If the vulnerable transports take significant losses, your invasion can no longer succeed, and considering the fact that it is there, you weren't interested in just flattening the place from orbit, so you are in a bind.
The same principle applies to naval and air warfare of both WW2 and modern times. If the defender's large combat craft formations have an option to fire at your transports instead of your combat craft, you screwed up, because they probably will, and it will probably cripple your invasion force before the ground battle even begins. As such, it would generally be important to intercept them at a safe distance.

Only by NGO standards. Was Hiroshima a genocide? Was Stalingrad a genocide? On the scale of planetary invasion, orbital firepower and peer conflict, a significant amount of collateral damage may not be avoidable, especially with a truly peer opponent who is prepared and has a developed planet with a population in billions at disposal.

1] The described relationship is more range = more cost. Especially with the caveat we are, of course, talking about effective range. Obviously, but since it had to be stated explicitly, it now has been so. I think we can be pretty comfortable in that assumption.

2] If the enemy controls the surface and cuts off the points of access/contact to the bunker, I'm not sure what you think is being acomplished by slowly starving out in a seige. One made much harder by losing any freedom of movement against enemy heavy artillery.

3] As a slight clarification, I'm assuming high powered electric drives, mostly to limit radiation exposure. Deep space with less radiation concern might use unshielded fusion torches. Though those still have such large radiation danger zones it may make fleet operations difficult. No matter what though, the trade off remains: If say you have a 10 GW engine, Say for a 100 ton craft, you can have 2,000 kn for 20 m/s^2 of thrust at 10 km/s exhaust velocity, or 200 km/s exhaust velocity and 100 kn for 1 m/s acceleration. The trade off will exist, tech informs the limits of those trade offs.

4] Sure, transports can be attacked. I just don't understand the idea of using an even less powerful attack even more trivially countered by an aware and and at all technological enemy, which seems like it would still require transports! Unless your kill bots are just teleporting to the surface?

5] Your specifically talking about nuking a continent, so, yeah, pretty genocidal attack. Especially since your likely doing way more damage to the civilian rather than military.

 

[Marduk]

Response to the last bit was probably overly glib.

It is however seeming to double down on the 50s idea that nuclear weapons makes war obsolete, which is not the case. If your goal is to just genocide with no limits, then just lots of nukes is an option. We have nearly 80 years of evidence however on how this is not the general case.

Nukes to destroy tuck launcher is a trade, but I'm not sure a reasonable trade. Nuke to destroy an area that might have a truck launcher, killing hundreds to thousands of people on some small probability of inflicting a casualty is even more questionable, pre-emtively destroying whatever it is your trying to capture.

I think you are underestimating the sheer scale of what hides behind the term "full scale planetary invasion". We're not invading Iraq here, we're invading the equivalent of Iraq, all the other countries, and probably some more if it's a highly developed planet, all at the same time.

On the contrary, without the taboo of using nukes as single planetary species, gray area of other orbital weapons and so on, nukes would be less of something that makes war obsolete, but merely yet another element of war, superheavy ordnance, like heavy thermobarics but still much bigger.

Nukes also make further ground operations more difficult as well. I don't think you as the attacker necessarily want to start out with mass nuking. That option exists, but it seems more profitable to use that in the negotiation of the combat, not part of the general combat. You don't have mutually assured destruction, at least tactically, but you as the attacker prefer not to be nuked too.

Depends on the nukes. Large, highly efficient warheads, especially of interstellar age design not so much.

The psychopolitics of nukes are unlikely to be remotely the same as now, after there are many highly developed planets, as for them there would be no fundamental difference between a nuke and any heavy orbital bombardment besides some radioactive contamination. And then there is the possibility of cleaner, bigger pure fusion nukes.

Your example also somewhat cheats by pre-supposing the missile carrier, which is a larger potential cost. Like suggesting there's no cost difference between a sidewinder shooting 10 km or one shooting 500 km away from base, ignoring the cost of the $20 million dollar fighter to carry the missile that far, or the cost of the early warning radar needed to find and track a target from that far away.

Again, you import atmospheric warfare paradigms to space even though they do not belong. There is no need for sustainer motors in space, and at this sort of range guidance works more like in anti ship missiles than A2A ones - the missile is fired in a direction where the ship commander thinks enemies are based on own intel and sensors, and the missile's own much shorter ranged radar seeker is programmed to activate and look for targets at some point close to where the enemy may lurk - much cheaper and easier to do than mounting a huge radar on every long range missile.

The direct costs to a 300 km vs 3,000 km range missile might be relatively small: 10x as large batteries for example. Keeping it effective at that range gets more tricky: you either need, I think its roughly 10x as strong sensors or comm systems for an equivalent effectiveness. This is a potentially large increase in minimum sensor package size, depending on that exact scaling.

Active for what? In space, there is no power saving inactivity mode for electronics, i guess. Friggin cold war era probes with primitive RTGs function for decades.
Also putting huge sensors on spammable missiles is completely optional if the cost is prohibitive, there are other solutions.

Your firing ship needs a better sensor package too, in order to line up effectively the longer range shot, growing the capabilities needed on your targeting platform too.

>needs
We are already beyond that point in warfare. It's an option, not a need. AWACS, buddy or sat data based firing solutions are already a thing in air and naval warfare.

Effectiveness rears its head again too: closing at, say 5 km/s gives your target 60 seconds of warning at 300 km. Like you said, at 60 km/h (approx. 15 m/s) that lets a target move 900 m, which would put the target within the radiation lethal radius of a 10 kton bomb, assuming nukes. This suggests very high likelihood of a kill, even if the enemy is completely prepared. If the enemy is not immediately aware and takes 30 seconds to react, they can only move 450 m/s, meaning you could get roughly the same kill probability (assuming perfect nuke accuracy) with a kiloton or less nuke.

Firing from 3,000 km however closing at 5 km/s gives 600 seconds of warning. That same target now can move 9 km with perfect awareness. You now want a 10 or so MT bomb to have sufficient blast range. Or, against a 100 kt bomb, the vehicle can take 300 seconds, some 5 minutes, to become aware they're targeted and react, and still possibly move out of the kill zone.

How does a target know that the missile coming at the planet from 3,000 km away know that the missile is coming for it, rather than any other place on the whole continent it is on?
The effective "awareness horizon" is going to be somewhere around mid-high atmosphere regardless of where the missile was launched.
And that's assuming the missile lacks any terminal maneuvering and terminal guidance.
If the guys up are dicks, the missile is delivering a HGV that as soon as it gets into remotely dense atmosphere will make a surprise turn and go for a target on the other end of the continent with 3 minute warning.

So, to preserve effectiveness over range requires a larger warhead, larger sensor pack, with more batteries, all maybe 10x as large warhead, giving you a 10x overall missile scale. But, you potentially need more delta v, through a mixture of more demanding orbital maneuvers and a desire to close faster. Bumping up from, say 3 km/s chem missile to 5 km/s, 3 km/s exhaust velocity increases the needed mass ratio from 3 to 6, so your actual missile scaling goes 20x larger.

So, the above gives you likely a more than 10x increase in cost for preserving effectiveness, which you are correct is the more correct metric to be discussing. effectiveness more or less go hand in hand when discussing range and accuracy for lasers or unguided, which is what I was thinking of when making the initial comment, but using the correct term of effectiveness, which range and accuracy are metrics, I'm not sure just because a weapon is guided its immune to the more range = more cost assumption.

Most of these things do not, or need not scale linearly to cost. Or at all. For example, due to complexities of tiny nuclear warheads, a simple 20kt one may even be cheaper than a 0.5kt one.

1] The described relationship is more range = more cost. Especially with the caveat we are, of course, talking about effective range. Obviously, but since it had to be stated explicitly, it now has been so. I think we can be pretty comfortable in that assumption.

And as i've demonstrated with modern drones, that doesn't even apply strictly now. In space it obviously applies even less.

2] If the enemy controls the surface and cuts off the points of access/contact to the bunker, I'm not sure what you think is being acomplished by slowly starving out in a seige. One made much harder by losing any freedom of movement against enemy heavy artillery.

Then the enemy has to leave sufficient forces watching the bunker, lest they want their rear struck by raids originating from the bunker. Classic medieval castle problem. You can ignore it and go around most of the time, but doing so has a price. If you have a whole network of bunkers and tunnels with many spaced out exits, then it gets really bad. Basically, militarized megalopolis subway system but deeper, with nuclear bunkers.

3] As a slight clarification, I'm assuming high powered electric drives, mostly to limit radiation exposure. Deep space with less radiation concern might use unshielded fusion torches. Though those still have such large radiation danger zones it may make fleet operations difficult. No matter what though, the trade off remains: If say you have a 10 GW engine, Say for a 100 ton craft, you can have 2,000 kn for 20 m/s^2 of thrust at 10 km/s exhaust velocity, or 200 km/s exhaust velocity and 100 kn for 1 m/s acceleration. The trade off will exist, tech informs the limits of those trade offs.

Assuming the values don't get high enough that other limits become the new bottlenecks, like structural integrity, human tolerance to acceleration or other technological limits.

4] Sure, transports can be attacked. I just don't understand the idea of using an even less powerful attack even more trivially countered by an aware and and at all technological enemy, which seems like it would still require transports! Unless your kill bots are just teleporting to the surface?

The ships for fighting other ship and the ship for invading and supporting the invasion are not necessarily the same ships.

5] Your specifically talking about nuking a continent, so, yeah, pretty genocidal attack. Especially since your likely doing way more damage to the civilian rather than military.

Is classic nuclear counter-military strike genocidal? After all, even if it targets only military units, in a densely populated country that's still going to do more damage to civilians than the military. It's basically the same as the problem of artillery\airpower in urban warfare, except taken 2 scales higher (planetary nuclear warfare being 1 scale higher). If you use it, civilians *will* die, at the same time, you can't afford to not use it when fighting a peer opponent because it's not worth trying as you will get curbstomped by a peer enemy in such circumstances.

 

[JagerIV]

Okay, you always do have the strangest things to take issue with. Lets focus then on more effective range (will you really force me to repeat this every single time?) = more cost.

your example was that less effective range (slow drone vs fast missile) can trade the effectiveness of the range for preserving the range. woop de doo, not counter to my argument in any way.

pre-supposing the sensors in "AWACs, buddy or sat data" does not make those suddenly free. This is the exact same "a missile fired from a $50,000 truck and a missile fired from a $50 million fighter have radically different ranges (sorry, effective range) as each other for the same price!" false argument you were making previously. Its a silly argument, please stop repeating it, and do me the curtesy of assuming I have a brain and am making general arguments in this general argument thread, not bog it down in tiny irrelevent points "we don't have to put it on the actual launcher! we can instead have the expensive sensors on a separate vehicle! That totally counters the point being made!"

Same with your silly argument "RTGs can function for decades! Therefore a missile optimized for 60 seconds of flight can have the exact same power pack as a missile operated for 6 minutes of flight!". This is clearly untrue: you missile might have 10-20 minutes of power by default (maybe the battery standardization falls at that scale). But, that simply means you have a 20-30 minute mission missile used in a 60 second mission, but that just means you have its designs optimized around higher operations. This could make reasonable sense. As you say (and I've never denied, thus the frustration dealing with this argument) things have different cost curves, and some may even be u curves, as shown in my initial post! You are arguing against points never made!

It might be worthwhile to return to the point of, well, this point. Why Long range = more cost mattered.

Why destroy something with a tank rather than an orbital laser?

The easy answer is that, all things considered, the tank is more effective. A big part of being more effective is cost. If getting a tank within 2 km of a target is more costly than sniping the target with an orbital laser 10,000 km away, it would be retarded to send the tank to do something the spaceship can do cheaper all costs considered.

This is much easier to illustrate in space fantasy, say Star Wars. Why did the trade federation send an army to fight the gungans, rather than shoot them from orbit? Well, the obvious answer would be that spacecraft can't really do that. Movie language, and various aspects of the universe generally, suggest a trade federation battleship can't actually snipe a Gungam formation from orbit, which is backed up by how we generally see such deployed: tactical Star destroyer fire support generally is not a thing: either fire is from closer in, or the Star Destroyers are involved in general large scale strategic bombardment, glassing cities, not individual bunkers.

This makes sense with the general WWII in space feel of the movies, where blasters clearly take time to arrive, aren't super accurate (since obviously fighters can survive in the presence of them) and engagements generally take place at closish ranges.

Assuming WWII like accuracy on the guns (spot size roughly 100 m at 10 km is what I used as an approximate) blaster cannons firing at 500 km up, a pretty low orbit overall, would have a spread of 5 km. Considering the battle apparently took place a mere 40 km outside the capital, using such inaccurate weapons would probably be danger close and risk damage to the capital in general and even friendly fire. An orbit more optimized for general blockade, say geostationary 30,000 km up or so would be a spot dimeter of 300 km. Given the relatively small size of the army compared to the city, such inaccurate weapons would certainly do more damage to the captured capital, and quite likely inflict more friendly fire, than they would do to the gungans!

So, within Star Wars like WWII in space dynamics, armies are actually relatively easy to justify: capital ship weapons (old star wars, not Disney star wars) simply don't have the accuracy to target anything smaller than a city, maybe even a county. 5 km diameter is an area of about 20 million m^2. If your target is even something large like a battalion, say covering an area 100x100 meters, you only have a roughly 1 in 2,000 chance of hitting the target. If dispersed for the bombardment, say into 10 man groups, you have something like a 1 in 4,000 chance of hitting any particular squad, and with 50 squads your looking at something like 200,000 orbital shots to destroy a battalion! More destruction per capital shot makes the math a bit better, but you still run into time constraints and problems if collatoral damage is at all a concern.

Achieving the equivalent effect at 500 km as a force 500 meters out is thus quite obviously going to be much more expensive at the long range: maintaining the effectiveness at longer range get much more expensive very quickly. And thus fighters and ground combat make perfect sense in a Star Wars like setting.

A more realistic setting your dealing with a much greater gray area, because many of the questions are less in the realm of "can", but "at what cost?" We could probably build an orbital kinetic weaponry now capable of destroying a tank. However, the total cost of firing such a rod from god system would probably come to something like $10 million dollars per shot at this point. This is very expensive compared to a javelin, hellfire, or tank round, and all of those also come with much more flexible and capable platform, while the orbital kinetic likely only has brief windows every couple of hours/days.

The effective cost of an orbital stike is so much higher than any current alternative, that using such a system as a general anti armor system would be incredibly stupid. Assumedly though, over time the difference in effective costs would narrow.

The question would be how much, and if they eventually cross over: does it become cheaper, with all relevant costs accounted for, to destroy a tank 10,000 km via orbital battleship than at 1 km with another tank?

My general sense is no. If that holds true, then there is room for ground forces as the economical force.

 

[Marduk]

Okay, you always do have the strangest things to take issue with. Lets focus then on more effective range (will you really force me to repeat this every single time?) = more cost.

your example was that less effective range (slow drone vs fast missile) can trade the effectiveness of the range for preserving the range. woop de doo, not counter to my argument in any way.

It is. Some better drones are about half as fast as subsonic missiles, still the range\cost curve can be *wildly* different. You are trying to shove extremely complex technological paradigms with a lot of cheats and exceptions and factors that matter in one application but not in other into simple graphs.

pre-supposing the sensors in "AWACs, buddy or sat data" does not make those suddenly free. This is the exact same "a missile fired from a $50,000 truck and a missile fired from a $50 million fighter have radically different ranges (sorry, effective range) as each other for the same price!" false argument you were making previously. Its a silly argument, please stop repeating it, and do me the curtesy of assuming I have a brain and am making general arguments in this general argument thread, not bog it down in tiny irrelevent points "we don't have to put it on the actual launcher! we can instead have the expensive sensors on a separate vehicle! That totally counters the point being made!"

As above.

Same with your silly argument "RTGs can function for decades! Therefore a missile optimized for 60 seconds of flight can have the exact same power pack as a missile operated for 6 minutes of flight!". This is clearly untrue: you missile might have 10-20 minutes of power by default (maybe the battery standardization falls at that scale). But, that simply means you have a 20-30 minute mission missile used in a 60 second mission, but that just means you have its designs optimized around higher operations. This could make reasonable sense. As you say (and I've never denied, thus the frustration dealing with this argument) things have different cost curves, and some may even be u curves, as shown in my initial post! You are arguing against points never made!

And you complained about bringing in pointless details... Battery packs are a tiny part of a missile's cost and weight budget either way.

It might be worthwhile to return to the point of, well, this point. Why Long range = more cost mattered.

Why destroy something with a tank rather than an orbital laser?

The easy answer is that, all things considered, the tank is more effective. A big part of being more effective is cost. If getting a tank within 2 km of a target is more costly than sniping the target with an orbital laser 10,000 km away, it would be retarded to send the tank to do something the spaceship can do cheaper all costs considered.

And yet the recent military actions by major powers have been exemplified by use of 50 million dollar jets to drop few hundred k worth of guided bombs on targets that technically could be handled by a bunch of commandos with rifles instead.
Not because it was most cost effective, but because of political considerations, logistics, force preservation and timing.
Cost is not the only military consideration in what weapons get used, often its far from dominant one, we don't have to pretend otherwise.

Timing is in fact a big one that you are not accounting for - such quick acting, strategic weapons can hit a target before it takes cover, changes its position, spends its ordnance or otherwise hitting it becomes less viable or meaningful, that's what makes those weapons so valuable.

This is much easier to illustrate in space fantasy, say Star Wars. Why did the trade federation send an army to fight the gungans, rather than shoot them from orbit? Well, the obvious answer would be that spacecraft can't really do that. Movie language, and various aspects of the universe generally, suggest a trade federation battleship can't actually snipe a Gungam formation from orbit, which is backed up by how we generally see such deployed: tactical Star destroyer fire support generally is not a thing: either fire is from closer in, or the Star Destroyers are involved in general large scale strategic bombardment, glassing cities, not individual bunkers.

Movie logic. The whole BDZ term comes from other Star Wars media, and they do orbital fire support in many games. We don't care about movie logic here.

This makes sense with the general WWII in space feel of the movies, where blasters clearly take time to arrive, aren't super accurate (since obviously fighters can survive in the presence of them) and engagements generally take place at closish ranges.

Assuming WWII like accuracy on the guns (spot size roughly 100 m at 10 km is what I used as an approximate) blaster cannons firing at 500 km up, a pretty low orbit overall, would have a spread of 5 km. Considering the battle apparently took place a mere 40 km outside the capital, using such inaccurate weapons would probably be danger close and risk damage to the capital in general and even friendly fire. An orbit more optimized for general blockade, say geostationary 30,000 km up or so would be a spot dimeter of 300 km. Given the relatively small size of the army compared to the city, such inaccurate weapons would certainly do more damage to the captured capital, and quite likely inflict more friendly fire, than they would do to the gungans!

Gungans were never truly a peer opponent to the Trade Federation to begin with, and they cared about taking the capital relatively intact. Neither side expected modern style urban warfare in the process, which would sorta destroy it anyway.
For what happens in modern warfare when an army faces even near-peer opposition in taking a city, even without use of strategic weapons, see: Stalingrad, Aleppo, Mariupol, Grozny.

So, within Star Wars like WWII in space dynamics, armies are actually relatively easy to justify: capital ship weapons (old star wars, not Disney star wars) simply don't have the accuracy to target anything smaller than a city, maybe even a county. 5 km diameter is an area of about 20 million m^2. If your target is even something large like a battalion, say covering an area 100x100 meters, you only have a roughly 1 in 2,000 chance of hitting the target. If dispersed for the bombardment, say into 10 man groups, you have something like a 1 in 4,000 chance of hitting any particular squad, and with 50 squads your looking at something like 200,000 orbital shots to destroy a battalion! More destruction per capital shot makes the math a bit better, but you still run into time constraints and problems if collatoral damage is at all a concern.

Achieving the equivalent effect at 500 km as a force 500 meters out is thus quite obviously going to be much more expensive at the long range: maintaining the effectiveness at longer range get much more expensive very quickly. And thus fighters and ground combat make perfect sense in a Star Wars like setting.

You ran yourself into analysis of movie logic based events, not even an in-setting paradigm.

Base Delta Zero

That 'Base Delta Zero' initiative the Empire keeps talking about? The new 'key to planetary liberation'? Don't believe it. It's a military code phrase, and it means TOTAL EXTERMINATION OF A TARGET POPULATION. It's completely loathsome.Sabine Wren, in her private journal Base Delta Zero (Δ) was...

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Orbital bombardment

Orbital bombardment, also known as an orbital strike, was a military strategy, where capital ships (such as Star Destroyers) would fire their main cannons from orbit to the surface of a planet, causing heavy damage to the designated target and its surrounding area. This strategy was used mostly...

starwars.fandom.com

Also, why the hell would advanced space age capital ship weapons be unable to do do what WW2 warships absolutely can do? 20m m^2 may look impressive, before you realize that even something as boring as a 155mm artillery shell has lethal radius against infantry of something about 50 meters with optimal shells, which means about 8000 square meters.
Which means statistically, you would need to fire 2500 of such shells over such area, and the rest is statistics.
An artillery brigade of 36 guns doing sustained fire (2 rounds per minute) would take 35 minutes to provide the required amount of fire. Suddenly it's not unreasonable at all...
Back to the ship analogy, you might need something along the lines of WW2 light cruiser to provide similar level of fire support even quicker (12 6 inch guns, 8 rpm thanks to semi automatic loading).

Do not underestimate the power of artillery, which orbital bombardment can be a very good stand-in for.

A more realistic setting your dealing with a much greater gray area, because many of the questions are less in the realm of "can", but "at what cost?" We could probably build an orbital kinetic weaponry now capable of destroying a tank. However, the total cost of firing such a rod from god system would probably come to something like $10 million dollars per shot at this point. This is very expensive compared to a javelin, hellfire, or tank round, and all of those also come with much more flexible and capable platform, while the orbital kinetic likely only has brief windows every couple of hours/days.

Rods from god are massively inefficient for destroying tanks (unless you make it some sort of cluster of frag weapon somehow, they are best suited against bunkers), and most of the cost would be the ridiculous modern day space lift cost.
How many times a day does a Javelin have a "window" to hit a tank thousands of kilometers away?
Put a nuclear 16x200kt MIRV on top of it and you have a 50-100m USD weapon, which will rout an armored division or few, with some proportion of it destroyed and the rest damaged, not destroy single tank, which looks far better economics wise - you're not getting an armored division for 100m.

The effective cost of an orbital stike is so much higher than any current alternative, that using such a system as a general anti armor system would be incredibly stupid. Assumedly though, over time the difference in effective costs would narrow.

The question would be how much, and if they eventually cross over: does it become cheaper, with all relevant costs accounted for, to destroy a tank 10,000 km via orbital battleship than at 1 km with another tank?

My general sense is no. If that holds true, then there is room for ground forces as the economical force.

If you account for the cost of deploying whole divisions of troops from the orbit, and fighting through hundreds of kilometers of unknown terrain to get your own tank with its support and logistics within 2 km of the enemy tank, and the losses they will take in the process, it can be much cheaper.

 

[stephen the barbarian]

despite being a "how to" guide on planetary invasions this vid devotes ~ 1/2 of it's run time to ''why'' including 10:00 debunking the idea that orbital bombardment is the only tool you need in your toolbox.
tl;dr:
1] your weapons may not be as effective as advertised
2] the planet may have defences that counter your weapons
3] it locks you out of lower cost options
4] politics and morality may prevent you from kicking off a campaign of orbital bombardment

 

[King Arts]

It seems comprehensive so yeah the biggest issue is morality and the opportunity cost of destroying the whole planet. It’s probably easier and more palatable to just blockade the world.

 

[Marduk]

It seems comprehensive so yeah the biggest issue is morality and the opportunity cost of destroying the whole planet. It’s probably easier and more palatable to just blockade the world.

In the circumstances we are discussing here, it is a false binary. It's not a choice between leveling the planet with orbital bombardment or pulling a Desert Storm with minimal casualties, friendly military or local civilian. My point is that if the planet is heavily defended, there is no choice, you pretty much need to use orbital bombardment to "soften up" the opposition and make landing ground forces feasible, then follow up with ground forces to clear up the leftovers, bunkers, survivors and the like.

If you skimp on the softening up, well all those weapons that supposedly threaten the bombarding warships, imagine what they will do to the landing transports, and the follow up logistical transports. Assuming somehow you manage to land some millions of troops anyway, well, how are they supposed to be taking ground with heavy opposition without doing major damage to the civilian infrastructure and populations while doing so? Are we talking of some theoretical way of ground warfare that's less destructive than any WW1 or later modern warfare? Technically you can avoid orbital bombardment just for optics reasons, but that's just a silly reason to massively increase your logistical burden by having to do the same destruction by delivering and supplying replacement artillery on the ground.
If you are fighting a major force of peer opponent in fortified positions and you have no massive artillery\airpower\orbital support, well, how the hell do you plan on winning at all?
Are cities destroyed with heavy artillery and combat engineer supported urban warfare less destroyed than cities destroyed with orbital bombardment?
Only fights against small colonies or not-so-peer-at-all opponents, aka planet space Iraq, can be done with more limited space based firepower use, limited to precision strikes against some main military facilities, without which the barely functional defenses won't be worth anything anymore and the defending troops will mostly surrender as soon as they see a bunch of invading troops.

 

[King Arts]

In the circumstances we are discussing here, it is a false binary. It's not a choice between leveling the planet with orbital bombardment or pulling a Desert Storm with minimal casualties, friendly military or local civilian. My point is that if the planet is heavily defended, there is no choice, you pretty much need to use orbital bombardment to "soften up" the opposition and make landing ground forces feasible, then follow up with ground forces to clear up the leftovers, bunkers, survivors and the like.

If you skimp on the softening up, well all those weapons that supposedly threaten the bombarding warships, imagine what they will do to the landing transports, and the follow up logistical transports. Assuming somehow you manage to land some millions of troops anyway, well, how are they supposed to be taking ground with heavy opposition without doing major damage to the civilian infrastructure and populations while doing so? Are we talking of some theoretical way of ground warfare that's less destructive than any WW1 or later modern warfare? Technically you can avoid orbital bombardment just for optics reasons, but that's just a silly reason to massively increase your logistical burden by having to do the same destruction by delivering and supplying replacement artillery on the ground.
If you are fighting a major force of peer opponent in fortified positions and you have no massive artillery\airpower\orbital support, well, how the hell do you plan on winning at all?
Only fights against small colonies or not-so-peer-at-all opponents, aka planet space Iraq, can be done with more limited space based firepower use, limited to precision strikes against some main military facilities, without which the defenses won't be worth much anymore and the defending troops will mostly surrender as soon as they see a bunch of invading troops.

Ok that's more reasonable using orbital bombardment as a replacement for conventional artillery if you are able to is fine. Star Wars does it for example where blasters can either be as destructive as a grenade, or they can be turned up to the level of nukes when the BDZ. If you are using it to help with tactical battles thats fine. But when people say orbital bombardment the first thing that comes to mind is strategic glassing where you are wiping out cities, or continents.

 

[Marduk]

Ok that's more reasonable using orbital bombardment as a replacement for conventional artillery if you are able to is fine. Star Wars does it for example where blasters can either be as destructive as a grenade, or they can be turned up to the level of nukes when the BDZ. If you are using it to help with tactical battles thats fine. But when people say orbital bombardment the first thing that comes to mind is strategic glassing where you are wiping out cities, or continents.

Movie inconsistencies aside, conventional artillery in sufficient quantity also wipes out cities, and if the city is well defended and has to be taken with ground forces, it will be used in said sufficient quantity anyway. So in that scenario, not using orbital bombardment to not destroy the city is kinda pointless.