The Role of Ground Forces in Interstellar Warfare
- Thread starter Zyobot
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bintananth
behind a desk
The modern tech ideas are applicable if you're talking interplanetary warfare with no FTL.
Interstellar? Um, no.
If you have to worry about Δv-budgets, mass ratios, transit times, and gravity wells you are not fighting on or above planet in a neighbouring star system because just getting there is an exercise in "Good luck with that."
Doomsought
Well-known member
Modern tech gives us a floor on what capabilities an interstellar civilization would be able to do. They are more advanced than us, so they should not be worse than us.
Vyor
My influence grows!
And if we look at the thread name...
They'd be so much more advanced than us that looking at our tech for context is like looking at the 4th god damn century for context on our modern tech.
Still, there is a huge scope of possible and obvious tech level related paradigm changes depending on pretty much how "hard" sci fi are we talking about and the Kardashev levels involved. Some may be limited to carpet nuking/rock dropping a planet while the other side tries to intercept that with lasers or missiles...
To those, modern/near future tech comparisons are most relevant.
Others may have c-fractional bombardment and planet destroying/ruining DEWs in case they don't care what's on a planet or at least a part of it. Need a landing zone, fire one of those on lower setting and turn a continent sized area into a glassy desert.
And then there is the staple, energy shield systems, presence, countering and use of which can completely dominate the ground-orbit warfare considerations in a whole bunch of mid to high tech settings.
Well, part of any ability to have a general discussion is an assumption that reality generally works like our own. For example, however interstellar works does not mean internal combustion engines work in a radically different mode than presently. Relativity physics does not invalidate all the things Newtonian physics gets right. The heliocentric model didn't invalidate that from our perspective the sun rises in the East and sets in the West.
Likewise, we should not expect future tech to invalidate what we experimentally can show is true currently: for example, discovering nuclear fission does not invalidate previous tests on how much energy is in gasoline. An engineer in the 1900s would give you roughly the same number for the energy content of gasoline as today, and a roughly equivalent theoretical maximum efficiency, since the maximum theoretical efficiency of a heat engine was established in the 1820-40s.
We today of course are much closer to the theoretical efficiency limits now than in the 1900s, but that also means we actually today have a good idea of how much output you can actually get: we actually can't really build engines dramatically more efficient than currently. If a distant world is using an internal combustion car 2,000 years from now, we actually don't have much rational reason to expect it to be dramatically different than a car now. Moderately better, but not likely revolutionarily better.
Conservation of energy means solar panels have a limit to how much energy you can collect per square meter based on the amount of sunlight, and the laws of thermodynamics means how much electricity we collect has to be less than the solar energy absorbed. I believe practical limits is something in the ball park of 30%, though double checking the wiki page you can push it a bit higher, though it get increasingly complicated squeezing the rest out.
So, its actually more reasonable that 2,000 years from now will look more like today than 2,000 years ago looks like today, because were closer to the final technological frontier. I have trouble picturing a future where there is not something very similar to our current trains and cars, likely with very roughly equivalent cargo capacities.
Admittedly, the obvious counter argument is that while a bow and arrow today do work the same as a bow and arrow 1,000 years ago, technology has almost entirely obsoleted bows and arrows as actual weapons of war. So it is perfectly possible that we might have something that revolutionary on such a basic element.
Its hard to really picture it though: as soon as gunpowder seems to have quickly been recognized as a potentially superior weapon as early as the 10th century with the fire lances, though its other shortcomings made gunpowder's absolute dominance take some 600 or so additional years, and edge cases do still exist to this day. Very few technologies are actually completely obsoleted.
Best I can picture is something like an electric gun, which while an improvement, does still feel like much more like a marginal improvement on current guns than a revolution.
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Hm, part of the big question falls under where a bit of technology falls under a civilizations "tech level", and thus a rough idea of comparative costs.
I sometimes find it useful to think in terms of the technological food chain/web, with your producers, primary consumers, etcetera.
Likewise, you have your supply chain/web, with equipment that takes more levels of manufacturing is generally more high tech, and also more expensive.
The rule of thumb i've come up with, since its simple and seems to generally work, is roughly an order of magnitude price increase per level.
So, for the car example above, raw ore is dirt cheap, about $100 dollars per ton. Say that's a level 1 product (stuff even cheaper like water which doesn't even require mining like iron or is something like a Level 0). That's processed to steel which is about $1,000 per ton, about in line with Level 2. Car engines seem to have roughly 300 kg of weight with $4,000 in cost, so about $13,000, which is pushing up for a level 3 tech, but the higher you get the more complicated you get. The level system would suggest a car as a level 4 tech should be roughly $100,000 per ton, but I can personally justify that as a lot of the weight is actually level 1-2, steel shaped into the frame and such.
So, the car likely averages to a 3.3 or so. Rough mental frame. The other important element is that, like a food chain, it also suggests you need a large base of "low tech" to support a peak of "high tech". You likely need 100s of billion tons of raw materials to get 10s of billions of tons of processed, excetera excetera.
Currently, space technology is both very high tech (and thus expensive and can only be a very ever really be a relatively small share of the economy and the work of the cutting edge of tech) and very inefficient (each unit has very low efficiency).
The big change for us would be how both of those changes, and how much. More efficient but still high tech means a basic space ship still costs a $100 million , and thus is still the prerogative of only the biggest, most advanced economies, but get more efficient. That $100 million ship holds 1,000 tons of cargo, delivers 10,000 tons of cargo per year, for 25 years, so its average capital cost per ton falls to $400 dollars per ton, maybe enough for a fee price of $1,000 a ton. This price point can support a lot of colonization, though still fairly expensive colonization.
Still means one ship costs as much as 1,000 trucks with 10,000 tons of cargo capacity, and a lot more with quicker turn arround.
If space can move down an average tech level however, with improved efficiency, that's really something: maybe engines merely $1 million per ton, and to that argument @Bear Ribs was having, perhaps designing for space is not so inherently difficult, and with more familiarity and scale we can do it for much cheaper. Maybe a $10 million ship with 1,000 tons capacity.
Now, it "only" costs as much as 100 trucks with 1,000 tons, an equivalent. Now theoretically an equal value of spaceships has an equivalent surge capacity to an equal value of trucks, though the trucks, given faster turn around, still have the ability to overtime transport far more capacity.
I seem to have rambled a bit and forgotten what exactly I was building to. And I'm already overate.
I think I've made an argument, and after a sleep maybe I can return to it and see if it was actually as relevant as I thought.
Good night all.
I sometimes find it useful to think in terms of the technological food chain/web, with your producers, primary consumers, etcetera.
Likewise, you have your supply chain/web, with equipment that takes more levels of manufacturing is generally more high tech, and also more expensive.
The rule of thumb i've come up with, since its simple and seems to generally work, is roughly an order of magnitude price increase per level.
So, for the car example above, raw ore is dirt cheap, about $100 dollars per ton. Say that's a level 1 product (stuff even cheaper like water which doesn't even require mining like iron or is something like a Level 0). That's processed to steel which is about $1,000 per ton, about in line with Level 2. Car engines seem to have roughly 300 kg of weight with $4,000 in cost, so about $13,000, which is pushing up for a level 3 tech, but the higher you get the more complicated you get. The level system would suggest a car as a level 4 tech should be roughly $100,000 per ton, but I can personally justify that as a lot of the weight is actually level 1-2, steel shaped into the frame and such.
So, the car likely averages to a 3.3 or so. Rough mental frame. The other important element is that, like a food chain, it also suggests you need a large base of "low tech" to support a peak of "high tech". You likely need 100s of billion tons of raw materials to get 10s of billions of tons of processed, excetera excetera.
Currently, space technology is both very high tech (and thus expensive and can only be a very ever really be a relatively small share of the economy and the work of the cutting edge of tech) and very inefficient (each unit has very low efficiency).
The big change for us would be how both of those changes, and how much. More efficient but still high tech means a basic space ship still costs a $100 million , and thus is still the prerogative of only the biggest, most advanced economies, but get more efficient. That $100 million ship holds 1,000 tons of cargo, delivers 10,000 tons of cargo per year, for 25 years, so its average capital cost per ton falls to $400 dollars per ton, maybe enough for a fee price of $1,000 a ton. This price point can support a lot of colonization, though still fairly expensive colonization.
Still means one ship costs as much as 1,000 trucks with 10,000 tons of cargo capacity, and a lot more with quicker turn arround.
If space can move down an average tech level however, with improved efficiency, that's really something: maybe engines merely $1 million per ton, and to that argument @Bear Ribs was having, perhaps designing for space is not so inherently difficult, and with more familiarity and scale we can do it for much cheaper. Maybe a $10 million ship with 1,000 tons capacity.
Now, it "only" costs as much as 100 trucks with 1,000 tons, an equivalent. Now theoretically an equal value of spaceships has an equivalent surge capacity to an equal value of trucks, though the trucks, given faster turn around, still have the ability to overtime transport far more capacity.
I seem to have rambled a bit and forgotten what exactly I was building to. And I'm already overate.
I think I've made an argument, and after a sleep maybe I can return to it and see if it was actually as relevant as I thought.
Good night all.
Eh, not necessarily. To take my example, FTL is likely to be high technology, and thus expensive and can't be a large portion of the economy. Then it comes down to if its a large scale or small scale tech. Take two high tech industries, processed Uranium and computer chips.
Only the highest tech, largest economies can produce them at any great scale. Both techs are very powerful, and very expensive.
Nukes however have a high minimum scale, I believe criticality is roughly 20 kg, and high returns to scale. And need lots of support equipment to really be efficient too. So, while you can't understand our current society without accounting for the existence of nuclear technology, day to day are not dramatically changed. The few thousand weapons and couple, I believe hundred, reactors are important, but not widespread.
Computers instead have a low minimal scale. So, even if chips are more advanced than nukes and more expensive per ton, say in my scale a level 6 at $10 million per ton, if you only need say 30 grams of chip in a 160gram Iphone that's only $300 of chips in a phone. That means it can be in everything.
So, as the science fiction comparisons, Halo civilization doesn't make sense without the slipsace drive, but the minimum scale of that technology seems pretty high: you need a huge slipspace drive to use, and it doesn't seem particularly useful at shorter ranges. Thus, despite the high tech, your average human city doesn't seem all that different, and most assumptions hold.
On the other hand, Mass Effect tech can work at extremely low scale, where some trace amounts in your blood streams gives you super powers. So you can have civilian flying cars, because clearly the minimum viable scale for mass effect tech is extremely low.
Though even there, Mass Effect tech obviously doesn't overthrow all out assumptions. Lots of understandings still hold.
Vyor
My influence grows!
Literally everything that uses ME tech completely obliterates our understanding of physics. For halo, everything they do except the most basic of guns does that.
Crom's Black Blade
Well-known member
There's a lot of assumptions here. Your assuming that the "strong"'s interests align with the "weak". Your assuming the "strong" are strong when, depending on the exact circumstances, that could be quite debatable. You make the assumption that because BLM was desired by those same "strong" authorities figures it either won't be desired in this circumstance or can't occur against the wishes of the "strong".
Since I don't proscribe to most if not any of these assumptions I can't agree with your summarization of my position and find it inadequate.
Because you brought up the police in a discussion of them responding to a crisis. The police are already in the cities dealing with the current crime level and arguably not doing the best job. If/when crime goes up their effectiveness will go down because their total numbers have not changed but their work load has.
If your not even going to mobilize the security guards but leave them scattered to the four winds with different employers and objectives then they are going to be less then useful.
As for the military, the fact they're likely engaged in fighting the enemy means you can't rely on them to be your hammer to smash people back in line. That there likely isn't going to be nearly as many soldiers as you suggest enacting this martial law and they likely won't have that much access to that heavier firepower because that will likely be needed elsewhere.
This is again were we differ. Under the scenario being discussed I'd lean towards the anti-government forces being better organized and having a greater concertation of guns. They're smaller and concerned with a much more narrow theater allowing more nimble decisions than a bloated government plagued with a myriad of other issues
It isn't so much helping the invaders but an example of how the powers that be will inflict the most petty, vindictive punishment on an undesirable for little to no reason other than to relish in that power over them. So no, I don't think the Manhattan DA would be handing out rifles and exonerating people of shooting looters if Mars invaded tomorrow.
Well it's a pretty large hurdle to any agreement if we can't agree on the starting assumptions. Obviously I find your arguments on the matter less than convincing for reasons already stated among others.
@Crom's Black Blade
I will continue this later, per per request.
On the specific broader question, the tech analysis does suggest a reason for ground troops: cost efficiency.
Lets say we had a military acquisition budget of $1 trillion, lets assume its divided between the 4 following catagories, you'd get roughly the following tons of each:
Definition of "units"
Processed: large bunker complex of roughly football field scale with 5 meter thick roof. 50,000 tons.
manufactured: Truck, 10 tons
Tank scale vehicles: 50 tons
Space vehicles: 1,000 tons
This is strongly suggestive of potential efficiency of force concerns: if Advanced tech can threaten your very advanced tech on anything better than a 200-1 trade, its quite worthwhile. If finding and reducing these quite substantial bunkers theorized here takes just time, that's a net gain.
Say for example a spacecraft took 1% per day attrition on hunting, and killed 1 tank per day and 100 trucks. So, a 100 dedicated to such a task loses one spacecraft per day, while inflicting 100 tank casualties and 10,000 truck casualties. This is a trade of $1.5 billion dollars to $1 billion in space assets, which is a positive trade. But, you are also tying up almost 50% of the fleet doing this. Possibly a 100% of warships.
If the planetary garrison is 10% of the enemies totals, so this planet has 5,000 tanks and roughly 250,000 trucks, it would take 50 days to attrition the tank force out and about 25 days. Maybe average to 1 month of fighting, to have all enemy vehicles destroyed, but also 30 spacecraft destroyed. $50 billion in surface material, $30 billion orbital. I victory, but potentially rather close, and depending on details may be less close. And a 166 "tanks" per spacecraft may not be so favorable an exchange ratio as raw dollars might suggest.
If instead you had the capacity to deploy 1,000 "tanks" to the planet in a day's drop. If its aggressive fighting, maybe 1 tank casualty per tank? Right away enemy tank casualties per day double, from 100 to 200. A fight to annihilation goes from 30-15 days. Even assuming all 1,000 tanks in the landing force were destroyed, that's $5 billion equipment lost on the ground, but potentially $15 billion saved in the air. Instead of 50-30 billion expenditure (1.6 - 1) you've gone to a 50-20 billion expenditure (2.5-1)
If defenses and positions work to such a way that you can build up (say spend a year moving 10,000 tanks to the planet). Maybe 10 ship losses in the supply, and then hit the enemy garrison in the one week lighting campaign, inflicting 1,100 casualties per day with your 10,000 "tanks" and 100 ships, resolving with 4 more space casualties and 400 armor casualties, for $16 billion losses overall (3-1)
If surface is an option, price differentials push for more combined arms, and the more cheaper options can be relied upon, the better.
I will continue this later, per per request.
On the specific broader question, the tech analysis does suggest a reason for ground troops: cost efficiency.
Lets say we had a military acquisition budget of $1 trillion, lets assume its divided between the 4 following catagories, you'd get roughly the following tons of each:
| Tech level | example | Cost per Ton | Tons per $1 billion | Units per $1 billion | Units per $250 billion |
| processed | concrete, steel | $1,000 | 1 million tons | 20 | 5,000 |
| manufactured | Cars, trucks | $10,000 | 100,000 | 10,000 | 2.5 million |
| advanced | tanks, radar | $100,000 | 10,000 | 200 | 50,000 |
| Very advanced | Aerospace | $1 million | 1,000 | 1 | 250 |
Definition of "units"
Processed: large bunker complex of roughly football field scale with 5 meter thick roof. 50,000 tons.
manufactured: Truck, 10 tons
Tank scale vehicles: 50 tons
Space vehicles: 1,000 tons
This is strongly suggestive of potential efficiency of force concerns: if Advanced tech can threaten your very advanced tech on anything better than a 200-1 trade, its quite worthwhile. If finding and reducing these quite substantial bunkers theorized here takes just time, that's a net gain.
Say for example a spacecraft took 1% per day attrition on hunting, and killed 1 tank per day and 100 trucks. So, a 100 dedicated to such a task loses one spacecraft per day, while inflicting 100 tank casualties and 10,000 truck casualties. This is a trade of $1.5 billion dollars to $1 billion in space assets, which is a positive trade. But, you are also tying up almost 50% of the fleet doing this. Possibly a 100% of warships.
If the planetary garrison is 10% of the enemies totals, so this planet has 5,000 tanks and roughly 250,000 trucks, it would take 50 days to attrition the tank force out and about 25 days. Maybe average to 1 month of fighting, to have all enemy vehicles destroyed, but also 30 spacecraft destroyed. $50 billion in surface material, $30 billion orbital. I victory, but potentially rather close, and depending on details may be less close. And a 166 "tanks" per spacecraft may not be so favorable an exchange ratio as raw dollars might suggest.
If instead you had the capacity to deploy 1,000 "tanks" to the planet in a day's drop. If its aggressive fighting, maybe 1 tank casualty per tank? Right away enemy tank casualties per day double, from 100 to 200. A fight to annihilation goes from 30-15 days. Even assuming all 1,000 tanks in the landing force were destroyed, that's $5 billion equipment lost on the ground, but potentially $15 billion saved in the air. Instead of 50-30 billion expenditure (1.6 - 1) you've gone to a 50-20 billion expenditure (2.5-1)
If defenses and positions work to such a way that you can build up (say spend a year moving 10,000 tanks to the planet). Maybe 10 ship losses in the supply, and then hit the enemy garrison in the one week lighting campaign, inflicting 1,100 casualties per day with your 10,000 "tanks" and 100 ships, resolving with 4 more space casualties and 400 armor casualties, for $16 billion losses overall (3-1)
If surface is an option, price differentials push for more combined arms, and the more cheaper options can be relied upon, the better.
The ability to build up does depend upon how easy to control an entire planet's orbital space in any particular instance is. To use my earlier example, a polar orbit will eventually overfly just about everywhere in a week or so, but the area its in at any one time is small over all. Or, if coming in straight for a landing rather than into an orbit, you have to be able to engage on that particular approach, not just wait a week for it eventually overfly your position.
This comes back to the issue of space being big. I was playing around with anti-orbit artillery. Mostly a conventional 130 mm and 250 mm cannon: average muzzle velocities (800-1,200 m/s) and then solid rockets. 130 had 1 stage, good for powered flight up to about 200 km, then drift up to about 400-500 km, depending on assumptions on drag and initial muzzle velocity. 250 seemed it could do powered flight up to about 500 km, drift/sustainer out to about 2,000 km. Toyed a little bit with smaller, but you have such low payload its hard to really push it out past 100 km reasonably.
Basically, these things with anti orbital rounds.
en.wikipedia.org
The idea being that unloading the targeting and control to the vehicle and initial charge can keep per round costs fairly low. More of a harassing weapon to keep maneuverable enemies on their toes, not letting them get too comfortable and providing a means to punish them if they do. And a cheap weapon to counter the enemies spam: Reaper 40 hovering over the battlefield at altitude on a predictable path? Rocket propelled round can take that. No flight altitude is completely safe. Transport craft staying low on a predictable orbit? An artillery vehicle can get there and send a harassing round.
Lot of vehicles with lots of rounds makes finding them all more difficult, and thus makes total orbital superiority more difficult.
But, such weapons also have very limited practical range, especially against moving targets: light gun is maybe a danger radius (can hit, not necessarily likely to hit) of maybe 100 km, medium maybe 500 km, heavy 1000-2000, depending on wither warhead or range is optimized for. Most likely closer to 1,000 km. This is coverage of roughly 30,000 km^2, 800,000 km, and 3 million km.
This is likely pushing what these weapons can do, and then only against "stationary" targets with nearly completely predictable movements.
On a planet with a surface area of 500 million, total coverage there requires 17,000 light weapons, 625 medium, or 166 heavy. With the additional caveat that the larger weapons are going to likely be significantly more costly per round and per launcher to achieve such practical long range, meaning there will be fewer shots per launcher and fewer available rounds. Likely many more support vehicles per launcher too, making the total number of vehicles need likely more comparable.
More range takes more cost, more advanced tech (and thus inherently rarer), and thus fewer units.
But, this also suggests that the hardest to take out part of the layered space defense also have the most limited range, and thus lowest ability to intercept on a global, rather than local, scale. Meaning gap and relative safe areas can be formed planetside to build up forces even without orbital control.
Given some preferences for overlapping fire and concentration of fire, having the option for unopposed landings, or at least generally unopposed landings, actually seems quite reasonable.
This comes back to the issue of space being big. I was playing around with anti-orbit artillery. Mostly a conventional 130 mm and 250 mm cannon: average muzzle velocities (800-1,200 m/s) and then solid rockets. 130 had 1 stage, good for powered flight up to about 200 km, then drift up to about 400-500 km, depending on assumptions on drag and initial muzzle velocity. 250 seemed it could do powered flight up to about 500 km, drift/sustainer out to about 2,000 km. Toyed a little bit with smaller, but you have such low payload its hard to really push it out past 100 km reasonably.
Basically, these things with anti orbital rounds.
Otomatic - Wikipedia
The idea being that unloading the targeting and control to the vehicle and initial charge can keep per round costs fairly low. More of a harassing weapon to keep maneuverable enemies on their toes, not letting them get too comfortable and providing a means to punish them if they do. And a cheap weapon to counter the enemies spam: Reaper 40 hovering over the battlefield at altitude on a predictable path? Rocket propelled round can take that. No flight altitude is completely safe. Transport craft staying low on a predictable orbit? An artillery vehicle can get there and send a harassing round.
Lot of vehicles with lots of rounds makes finding them all more difficult, and thus makes total orbital superiority more difficult.
But, such weapons also have very limited practical range, especially against moving targets: light gun is maybe a danger radius (can hit, not necessarily likely to hit) of maybe 100 km, medium maybe 500 km, heavy 1000-2000, depending on wither warhead or range is optimized for. Most likely closer to 1,000 km. This is coverage of roughly 30,000 km^2, 800,000 km, and 3 million km.
This is likely pushing what these weapons can do, and then only against "stationary" targets with nearly completely predictable movements.
On a planet with a surface area of 500 million, total coverage there requires 17,000 light weapons, 625 medium, or 166 heavy. With the additional caveat that the larger weapons are going to likely be significantly more costly per round and per launcher to achieve such practical long range, meaning there will be fewer shots per launcher and fewer available rounds. Likely many more support vehicles per launcher too, making the total number of vehicles need likely more comparable.
More range takes more cost, more advanced tech (and thus inherently rarer), and thus fewer units.
But, this also suggests that the hardest to take out part of the layered space defense also have the most limited range, and thus lowest ability to intercept on a global, rather than local, scale. Meaning gap and relative safe areas can be formed planetside to build up forces even without orbital control.
Given some preferences for overlapping fire and concentration of fire, having the option for unopposed landings, or at least generally unopposed landings, actually seems quite reasonable.
Requires absolute sci fi level performance characteristics for the gun, and even then, you may need bigger guns than you think. Forget about 130mm, go straight to battleship calibers and two stage rounds.The ability to build up does depend upon how easy to control an entire planet's orbital space in any particular instance is. To use my earlier example, a polar orbit will eventually overfly just about everywhere in a week or so, but the area its in at any one time is small over all. Or, if coming in straight for a landing rather than into an orbit, you have to be able to engage on that particular approach, not just wait a week for it eventually overfly your position.
This comes back to the issue of space being big. I was playing around with anti-orbit artillery. Mostly a conventional 130 mm and 250 mm cannon: average muzzle velocities (800-1,200 m/s) and then solid rockets. 130 had 1 stage, good for powered flight up to about 200 km, then drift up to about 400-500 km, depending on assumptions on drag and initial muzzle velocity. 250 seemed it could do powered flight up to about 500 km, drift/sustainer out to about 2,000 km. Toyed a little bit with smaller, but you have such low payload its hard to really push it out past 100 km reasonably.
Basically, these things with anti orbital rounds.
Otomatic - Wikipedia
The idea being that unloading the targeting and control to the vehicle and initial charge can keep per round costs fairly low. More of a harassing weapon to keep maneuverable enemies on their toes, not letting them get too comfortable and providing a means to punish them if they do. And a cheap weapon to counter the enemies spam: Reaper 40 hovering over the battlefield at altitude on a predictable path? Rocket propelled round can take that. No flight altitude is completely safe. Transport craft staying low on a predictable orbit? An artillery vehicle can get there and send a harassing round.
Lot of vehicles with lots of rounds makes finding them all more difficult, and thus makes total orbital superiority more difficult.
But, such weapons also have very limited practical range, especially against moving targets: light gun is maybe a danger radius (can hit, not necessarily likely to hit) of maybe 100 km, medium maybe 500 km, heavy 1000-2000, depending on wither warhead or range is optimized for. Most likely closer to 1,000 km. This is coverage of roughly 30,000 km^2, 800,000 km, and 3 million km.
This is likely pushing what these weapons can do, and then only against "stationary" targets with nearly completely predictable movements.
On a planet with a surface area of 500 million, total coverage there requires 17,000 light weapons, 625 medium, or 166 heavy. With the additional caveat that the larger weapons are going to likely be significantly more costly per round and per launcher to achieve such practical long range, meaning there will be fewer shots per launcher and fewer available rounds. Likely many more support vehicles per launcher too, making the total number of vehicles need likely more comparable.
More range takes more cost, more advanced tech (and thus inherently rarer), and thus fewer units.
But, this also suggests that the hardest to take out part of the layered space defense also have the most limited range, and thus lowest ability to intercept on a global, rather than local, scale. Meaning gap and relative safe areas can be formed planetside to build up forces even without orbital control.
Given some preferences for overlapping fire and concentration of fire, having the option for unopposed landings, or at least generally unopposed landings, actually seems quite reasonable.
The cost increase of larger round is not going to be much in comparison to the cost of guidance you have to put in the rounds for them to be worth anything at all. Unguided artillery with lots of rocket assistance is notoriously inaccurate at long ranges even for normal artillery purposes, good luck shooting at spaceships, with CEP going to hundreds of meters even at relatively low for our purposes ~70km.
The other problem with unguided rounds is that they are completely predictable to the PD weapons of the targeted ship, and at the velocities involved give plenty of time for even several intercept attempts. What essentially this would need to be is for the shell to be a capsule containing one or several small anti-spacecraft missiles reinforced to survive being fired out of a cannon. And at that point may as well be more conventional and put those on a big first stage carrier missile.
Naw, part of the point is to give some limited anti orbital package to pre-existing anti air and artillery rounds.
I mean, the 100-500 km range at these speeds is 1-5 minutes from fire. That is not a particularly huge window. Especially if a cannon fire is not immediately detected. We are talking something very similar to the Extended range munition for the 5 inch gun or the system for the 8"/55.
A gps guidance so it hits the area of space aimed at doesn't seem particularly out there. Proximity sensors don't seem particularly expensive, though maybe cheap camera's would be more viable. I'm agnostic on the specifics of the optimal cheap sensor.
These are flak rounds/JDAM equivalents, and could probably be manufactured for comparative amounts. Maybe the 127 mm is $50,000 dollar round, so $1 million dollars of munition would be 20 rounds. Its a more cost effective way to take out a $100,000 cube sat than a multi-million missile. If a $100 million dollar fighter/weapon platform gets caught totally unaware, even better exchange. But, if it takes 1,000 rounds to mission kill that $100 million fighter, that's still a potentially worthwhile trade. If you expend 100 rounds to disrupt an attack run, that's worthwhile.
And for an orbital denial role, for a billion dollars you can purchase 20,000 rounds and disperse that among the ground forces so low orbit is never entirely safe, vs 10 space fighters which may be attritted fairly quickly.
Doesn't mean the space superiority fighters don't have value or a place, but such weapon systems seem viable and technically feasable.
There is cheap, and there is ASAT munitions. It's ridiculous to think you can get them cheaper than a common air to air missile.Naw, part of the point is to give some limited anti orbital package to pre-existing anti air and artillery rounds.
I mean, the 100-500 km range at these speeds is 1-5 minutes from fire. That is not a particularly huge window. Especially if a cannon fire is not immediately detected. We are talking something very similar to the Extended range munition for the 5 inch gun or the system for the 8"/55.
A gps guidance so it hits the area of space aimed at doesn't seem particularly out there. Proximity sensors don't seem particularly expensive, though maybe cheap camera's would be more viable. I'm agnostic on the specifics of the optimal cheap sensor.
For starters, what kind of 5 inch or 8 inch gun is going to get you even close to this kind of altitude, nevermind keeping a decent speed while at it?
From your link:
Where's 24km, where's intercepting spacecraft in low orbit?
Also say goodbye to your space GPS when you are defending from a space invasion and are desperate enough to cheap out on weapons this badly.
You can start talking about ground to orbit rifles at this level of fiction. These rounds aren't getting this high without some insane advances in propellants, and if they are, they aren't hitting shit with that price range.
This is the kind of gun you need to talk about if you want to reach space with it.
And do not get disoriented by the surprisingly long range 155mm projectiles as their trick with that range is based on gliding, it's not helpful for purposes of going up.
Still, you need some kind of crazy ass light gas guns, huge multi stage missile bus rounds, or railguns to even hope of reaching that high, and only then you have to worry about hitting things.
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Doomsought
Well-known member
For asat weapons, I think a low cost laser system that is designed mission kill orbital weapons and scouts by seeking out optics and blind them.
Well, obviously an artillery round is different than an anti orbit round. "like" is the important qualifier.
After all your long arguments for solid propellants, to so so utterly lose faith in them so quickly.
5 inch gun is a normal velocity gun, 800-1200 m/s, firing a 30 kg projectile with a mass ratio of 3. Modern solids which apparently are getting approximately 3 km/s exhaust velocity means that's 3.2 km/s. I rounded down to 3 km/s for conservatism. Your getting basically a 2 stage missile for the price of a 1 stage missile. Gun gets the initial high acceleration kick to push through the thicker parts of the atmosphere relatively quickly, lowering overall drag, while providing a lot of initial acceleration minimizing gravity losses.
2 minutes of powered flight up to about 100-200 km, depending, can then drift up to about 500 km. Short range point defense, counter spam/harassment weapon. Maybe couple of kg of explosives for some fragmentation effects, or final diverts if its supposed to be a direct impact weapon.
10 inch gun is normal velocity, I assumed 800 m/s, 200 kg. First stage mass ratio 2 for 2 km/s, gets above the majority of the atmosphere, then second stage another mass ratio of 2 for another 2km/s, for a total of about 5 km/s enough to theoretically drift to an altitude of about 2,000, then either a 50 kg warhead, or final impact package, depending.
There's no real math reason it wouldn't work. We don't have any rounds like this because there's no reason to have rounds like this: most satellites are higher, its a multi billion development role, and most current targets aren't particularly numerous so a cheap option isn't needed.
If you have common low orbital support and enemies with spammable space assets, and ground forces needing to worry about orbit to ground missiles and craft, there is more of a reason.
After all your long arguments for solid propellants, to so so utterly lose faith in them so quickly.
5 inch gun is a normal velocity gun, 800-1200 m/s, firing a 30 kg projectile with a mass ratio of 3. Modern solids which apparently are getting approximately 3 km/s exhaust velocity means that's 3.2 km/s. I rounded down to 3 km/s for conservatism. Your getting basically a 2 stage missile for the price of a 1 stage missile. Gun gets the initial high acceleration kick to push through the thicker parts of the atmosphere relatively quickly, lowering overall drag, while providing a lot of initial acceleration minimizing gravity losses.
2 minutes of powered flight up to about 100-200 km, depending, can then drift up to about 500 km. Short range point defense, counter spam/harassment weapon. Maybe couple of kg of explosives for some fragmentation effects, or final diverts if its supposed to be a direct impact weapon.
10 inch gun is normal velocity, I assumed 800 m/s, 200 kg. First stage mass ratio 2 for 2 km/s, gets above the majority of the atmosphere, then second stage another mass ratio of 2 for another 2km/s, for a total of about 5 km/s enough to theoretically drift to an altitude of about 2,000, then either a 50 kg warhead, or final impact package, depending.
There's no real math reason it wouldn't work. We don't have any rounds like this because there's no reason to have rounds like this: most satellites are higher, its a multi billion development role, and most current targets aren't particularly numerous so a cheap option isn't needed.
If you have common low orbital support and enemies with spammable space assets, and ground forces needing to worry about orbit to ground missiles and craft, there is more of a reason.
WTF do solid rocket propellant have to do with artillery? Those aren't even the same chemicals.
Many ICBMs run on solid propellants, but they aren't fired out of a 155mm gun, and so they don't need to meet any of the engineering requirements that come with it.
This is not engineering, this is highschool physics class level of thought out.
Congratulations, you shave off a stage from your missile.
In exchange, you have to compromise the design of the whole rest of the missile to survive something along the lines of tens of thousands of G's due to being fired out of a fucking cannon. Guess if you saved money then...
How do you fit a 4 km\s dV two stage guided missile in a 200kg mass budget, and do it after reinforcing it to be fired out of a cannon, which normal missiles have precisely zero chance of being functional afterwards, with the issue getting worse proportionally to the length of the missile?
For comparison, AMRAAM is a single stage missile with something about 1200-1500 m\s delta V and weights 160 kg and has about 1\1000 of the required G tolerance.
And as i said before, you can only mass ratio things willy-nilly in theory, in practice sooner rather than later engineering of many pieces, nevermind the physics of sectional density, materials engineering and thermodynamics say hold on a minute.
Yes, there is no *math* reason it wouldn't work. There are several doctorate's worth of physics and engineering reasons why it wouldn't work though, and if you used super cool future tech to make it work, it would suddenly stop being cheap.
If rounds like this could be made, they absolutely would - not for use against space assets, but to stick a tiny, SDB style GPS guided gliding bomb, like the extended range 155mm shell programs mentioned, which if delivered to such altitudes would be able to reach at least SRBM like ranges. Who would say no to 155mm artillery with the range of ATACMS or Iskander?
Considering the extremely low performance of such weapons against defensive maneuvers and tools, the whole infrastructure needed to fire and aim such weapons to fire them in the first place costs more than the meager effect one would expect from them.
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Eh, I disagree. If you want to argue things that very nearly exist are impossible, you do you. I'm sure what we have in 2020 is the absolute limit of engineering. RAPs are super duper impossible engineering problems with no functional examples and no room for improvement if improvement was necessary. And not something that has been in development with functional prototypes and example since the 1980s.
Why do you think an AMRAAM has a delta v of 1,200-1500 m/s? It has a max speed around that, but that's something very different. Basic calculations suggest it would suffer something along the line of 4-6 m/s of drag at operating altitude and speed. Suggesting something like 250 m/s lost to drag, gravity losses may be another 250 m/s. So, were potentially already talking about 2 km/s delta v, in a missile that has to be optimized for the high drag environment of lower atmosphere against assumedly maneuverable targets.
One of the advantages of the gun is minimizing time spent in the densest part of the atmosphere, meaning you can focus more an high performance fuel, rather than a large low performance high thrust fuel, which balloons the overall rocket scale. Very high speeds low down would actually be counter productive, inducing more drag, making relatively low velocity guns better than high velocity ones on an efficiency measure.
I just don't buy that this is particularly impossible, given all the other things we can do. Maybe missiles are cheaper or better for other reasons, in which case they would be more common. I am perfectly open to that argument. Your argument though seems to almost require a belief that what we do now, what we've been able to do since the 80s, is impossible. Not un-cost effective, impossible.
Why do you think an AMRAAM has a delta v of 1,200-1500 m/s? It has a max speed around that, but that's something very different. Basic calculations suggest it would suffer something along the line of 4-6 m/s of drag at operating altitude and speed. Suggesting something like 250 m/s lost to drag, gravity losses may be another 250 m/s. So, were potentially already talking about 2 km/s delta v, in a missile that has to be optimized for the high drag environment of lower atmosphere against assumedly maneuverable targets.
One of the advantages of the gun is minimizing time spent in the densest part of the atmosphere, meaning you can focus more an high performance fuel, rather than a large low performance high thrust fuel, which balloons the overall rocket scale. Very high speeds low down would actually be counter productive, inducing more drag, making relatively low velocity guns better than high velocity ones on an efficiency measure.
I just don't buy that this is particularly impossible, given all the other things we can do. Maybe missiles are cheaper or better for other reasons, in which case they would be more common. I am perfectly open to that argument. Your argument though seems to almost require a belief that what we do now, what we've been able to do since the 80s, is impossible. Not un-cost effective, impossible.