How the hell do ground invasions work in Star Wars?

[Abacus]

My question is "If there are only 25,000 ISDs, how does the empire land enough men to effectively invade planets?"

You mean, manpower-wise? We're talking about a GALACTIC EMPIRE here. And, as I said, it depends on the individual planets and the objectives being sought by the invaders.

Not to mention, often enough, the Imperial forces don't need to actually land troops for invasion -- but rather use their space forces to compel a planet to surrender without a fight, give up their arms, and then occupy it with a small, mobile, elite force of stormtroopers. (See: Thrawn's occupation of Ukio)

[Shroom Man 777]

Assuming for every heavy-hitting ISD (which by galactic standards is a fairly impressive "main warship" without getting into the larger star dreadnoughts and other Mandator-like vessels) there are... what? Half a dozen? A whole dozen? Escorting or surrounding vessels. Those Acclamators and Venators. Plus frigates or corvettes. And *more* when it comes to unarmed transport ships. I really don't think there's a problem. It just depends on the proportion, how many non-ISD warships does the Empire have for every ISD?

Like, for every frontline BDZ-capable ISD, how many of those of say fractalsponge's giant support ships are there? Are there similarly-sized troop transports? Like Dune Heighliners? If a planet's orbit is secured, all sorts of unarmed giant transports might appear.

Like, what are the "Big Corellian Ones" Han speaks of when he talks about outrunning Imperial ships...

[Lord Revan]

My question is "If there are only 25,000 ISDs, how does the empire land enough men to effectively invade planets?"

You mean, manpower-wise? We're talking about a GALACTIC EMPIRE here. And, as I said, it depends on the individual planets and the objectives being sought by the invaders.

Not to mention, often enough, the Imperial forces don't need to actually land troops for invasion -- but rather use their space forces to compel a planet to surrender without a fight, give up their arms, and then occupy it with a small, mobile, elite force of stormtroopers. (See: Thrawn's occupation of Ukio)

Even on systems where victory thru orbital domination isn't possible it wouldn't surprice me that you'd have initial force of troopers trained for fast shock operations to decapitate the enemy forces by eliminating their leaders, with the rest of the troops landing during the chaos as the enemy tries to figure out who is in charge in their troops with troops picked for their loyality handling the occupation. Also I suspect that empire relies on local "security forces" on planets where that's possible, hell even Lothal might have had local security forces had it not been known have been a (former) hot bed for discidents.

After all the empire probably doesn't need massive occupation forces on Kuat or Corusant.

[Abacus]

We do know that they have SCAR Troopers that are responsible for infiltration, assassination, and asymmetric warfare missions.

This also brings into assumption that some Imperial governors, planetary or sector, didn't use droids. I know for a fact that if I were an Imperial governor put in charge of a formerly Separatist world, that I'd be taking over management of the B1s, B2s, and Droidekas that were on-planet for my own use. I don't imagine that they would be popular, but if I were a moff facing reduced manpower or spending from the Core Worlds, because I'm in the Outer Rim and often forgotten, then I'd look to supplement my forces in whatever way I could. We already know from the comics that various rebel and criminal organizations used former battle droids -- so why not the Imperials? Just one thing to think about, in terms of occupational forces.

EDIT: In canon sources, we know (thanks to Star Wars: Commander) that Imperials often used Droidekas in defense of imperial bases.

[ray245]

Assuming most planets are heavily demilitarized like Naboo and most of the planets seen in the Clone Wars, this would make most ground invasion fairly easy.

[Ender]

But if you're landing 300,000 soldiers in the first wave, and the defenders have ten million soldiers, it seems that you won't have a chance to get a beachhead inside the shield.

Those ten million will be spread out covering the entire planet, while your forces will be concentrated. In 1944, the German Army had close to a million men in the west, awaiting the allied invasion, against a D-Day assault force of 130k.

Also, it's not just if you can get a beachhead, it's whether you can keep it. If you land 300,000 men vs their 100,000, but then six hours you managed to get 300,000 more, and they have their whole ten million, you're screwed. This is different from D-Day because there, the germans were further from Normany on average, if anything. Does it take longer to move a corps halfway across the world than across a sector? I'm not sure, but I don't think so.

Well first I'd question if the typical planet is going to have combined arms field army of 10 million men. With one world government for most of their history these places aren't going to have much need for armor battalions. I'd imagine it falls more in line with the advanced counter terror model we've seen floated these last few years - special operations plus air support plus police. Add in government/royal guards and the odd private army/personal regiment of the odd local oligarch (which now that I think about it is also part of the modern counter terror model) and that sums up what we see in the EU

But let's operate from the idea they have 10 million men under arms in a standard combined arms field army. Does that planet have a full supply chain to manufacture everything they need? They don't need to import any components or materials to make blasters, repulsers, walkers, or fighters? They make all their own warfighting material 100% in house as a partial autarchy?

If they do make it all on planet, is their production rate and reserves sufficient to match the deployment rate of the Inperials? Maybe local troops can beat back the landing forces trading out 10 imperial walkers for every 1 of theirs, but if that 11th walker gets dropped off before your next walker rolls off the assembly line you are still gonna lose.

Let's say you solve the off world supply chain problem by downgrading the tech. Lord knows a dumb shell explodes with the same force as a guided munition. How does that match up with relative effectiveness with the conventional sf weaponry? If you have to use five of them to do what one regular one would do then even if you've solved the off world problem you are still in a long term losing proposition.

I expect the number of places that a) can field large "modern" armies and b) supply them for an extended period (either through local production or more likely sufficient stockpiles) and c) have sufficient orbital defenses to prevent immediate surrender and d) didn't have their leaders bought into the empire rather than forced in is pretty small, and make up the sources of those outer rim sieges. More likely just having an attack force pop in starts a very short timer until supplies run out so any resistance forces are the type of commandos and operatives that we see hop in freighters, fly off, and join the rebellion.

[Abacus]

Also, I might add that the old, original Star Wars Clone Wars tv show (2003) seemed a lot better at displaying planetary assault than anything else. It's on YouTube btw, if anyone wants to go watch. I'd link it here, but I'm pretty sure it's not allowed.

[Abacus]

Also, it's not just if you can get a beachhead, it's whether you can keep it. If you land 300,000 men vs their 100,000, but then six hours you managed to get 300,000 more, and they have their whole ten million, you're screwed. This is different from D-Day because there, the germans were further from Normany on average, if anything. Does it take longer to move a corps halfway across the world than across a sector? I'm not sure, but I don't think so.

-snip-

I'd also add that just because you have ten million soldiers doesn't mean that you can deploy them effectively. Modern combat doesn't lend itself to you having literal phalanxes of men marching forward into combat. The Separatists could do it, because (a) droids won't run in the face of giant losses and (b) they can always produce more. The Old Republic and the Empire, by contrast, had to employ more modern forms of unit tactics by necessity. Otherwise they'd lose as many combat effectives, if not more, than the Separatists did.

[Lord Revan]

We know that neither the Rebel Alliance/New Republic or Galactic Republic/Empire is incapable of using close in-air support. Also just because you might not be able to use indiscriminate bombardment to force the planet to surrender, it doesn't mean you can't use surgical strikes against key tactical/strategic objectives.

Numbers aren't everything after all, quality of your troops, equipment, tactics and strategies matters just as much as quanity of those troops and it wouldn't surprice me at all if the imperial high command made sure that they had the best toys and that if there was a planet the Empire had to invade to take over they'd have their best quality troops at hand. Oh and the empire isn't really conserned about collateral damage to the civilian population (if it isn't too exessive I assume)

[Simon_Jester]

Spread out over a planet, with transportation assets on the same scale that Earth has such assets, and remembering that a LOT of Star Wars vehicles are flying vehicles or all-terrain hovercraft, even a lot of cheap low-end stuff... Deploying ten million men isn't such an insurmountable problem unless the threat is itself so concentrated that there's no place to deploy the ten million men to.

In which case you just send a small fraction of your overall force, funneling in reinforcements as fast as necessary to contain and erode away the pocketed, surrounded threat you're responding to.

The trick is that trying to win battles with superior equipment and tactics but much lower numbers generally doesn't work unless you have a decisive advantage of mobility and coordination or a huge, overwhelming advantage in firepower. The latter isn't really possible in Star Wars ground battles because both sides tend to have comparable weapons: variations on the theme of 'blaster.' When the Imperials break out something huge like an AT-AT that's immune to heavy turreted weapons, it's a surprise, which suggests that such superheavies aren't the norm, even for the Imperials who undoubtedly have the capability to use things like that.

So it comes back to mobility and coordination. An invader coming down from space has great mobility advantages, as long as they can neutralize surface-to-orbit weapons... but they also have to neutralize the enemy's mobility, because even commandeered civilian transport in Star Wars would be something like "a million flying cars and trucks" and would give excellent mobility by itself.

That's the tricky part, I suspect- coordinating the planetary invasion, committing enough troops to achieve intended objectives while preserving economy of force, AND using fighter support and orbital fire to break up enemy concentrations and maintain air superiority so that they can't just drop hundreds of thousands of airmobile troops on your invasion bridgeheads.

[Shroom Man 777]

Hmmm... the AT-ATs are just a surprise to insurgents in highly mobile space-guerrilla campaigns where secrecy, avoiding ISD-assaults and ground incursions in the first place, are the order of the day. AT-AT-scale things are common even in garrison worlds like Scariff... and in the Clone Wars they were par the course.

Rebels show us that TIE fighters have obscene maneuverability, flying slowly and using their anti-grav stuff they can even fly sideways like helicopters (though of course in combat situations this might be hard due to enemy weapons fire). Rogue One's deleted scenes also show Jyn having a face to face encounter with a possibly hovering TIE.

So I wonder how TIE spam for close and REALLY close air support would work for the Imperials.

[Rhadamantus]

Spread out over a planet, with transportation assets on the same scale that Earth has such assets, and remembering that a LOT of Star Wars vehicles are flying vehicles or all-terrain hovercraft, even a lot of cheap low-end stuff... Deploying ten million men isn't such an insurmountable problem unless the threat is itself so concentrated that there's no place to deploy the ten million men to.

In which case you just send a small fraction of your overall force, funneling in reinforcements as fast as necessary to contain and erode away the pocketed, surrounded threat you're responding to.

The trick is that trying to win battles with superior equipment and tactics but much lower numbers generally doesn't work unless you have a decisive advantage of mobility and coordination or a huge, overwhelming advantage in firepower. The latter isn't really possible in Star Wars ground battles because both sides tend to have comparable weapons: variations on the theme of 'blaster.' When the Imperials break out something huge like an AT-AT that's immune to heavy turreted weapons, it's a surprise, which suggests that such superheavies aren't the norm, even for the Imperials who undoubtedly have the capability to use things like that.

So it comes back to mobility and coordination. An invader coming down from space has great mobility advantages, as long as they can neutralize surface-to-orbit weapons... but they also have to neutralize the enemy's mobility, because even commandeered civilian transport in Star Wars would be something like "a million flying cars and trucks" and would give excellent mobility by itself.

That's the tricky part, I suspect- coordinating the planetary invasion, committing enough troops to achieve intended objectives while preserving economy of force, AND using fighter support and orbital fire to break up enemy concentrations and maintain air superiority so that they can't just drop hundreds of thousands of airmobile troops on your invasion bridgeheads.

And, there should be thousands of worlds this size (10 billion people or so) per sector, if we use the high end population numbers. If Sector forces have difficulty taking one planet, well...

[Shroom Man 777]

I guess that's precisely why in the Clone Wars there were still planetary wars of attrition...

[Abacus]

And, there should be thousands of worlds this size (10 billion people or so) per sector, if we use the high end population numbers. If Sector forces have difficulty taking one planet, well...

Then you bombard it into submission as a warning to the other systems in the sector. An insurmountable superiority in space with ISDs can be just as fear-causing as the Death Star -- especially if broadcast across the sector; much as Tarkin had the death of Eriaduan pirates broadcast across the sector to discourage further pirate raids. (See "Tarkin" book for details)

[Shroom Man 777]

Or just blockade it. Heck, even project a REVERSE planetary shield! To prevent anyone from leaving the world! What on that world is so vital that an invasion has to be staged? If it's population is in the billions, but if the world's ecosphere is either devastated or lousily terraformed making it a typical Star Wars one-climate world then either it can't feed itself and thus relies on imports from agriworlds, or if it can then just slaughter all the nerfs and banthas and let the people starve. Even if they don't starve because they have megatons of stockpiled Space MREs... then just isolating them from the rest of the galaxy will make them irrelevant. Other less troublesome worlds can be pacified and then the Empire can save the best for last. Or use ISB operatives and stage internal coups or something. Promise the coup plotters positions as planetary governors with their own spanking ISDs... and Krennic capes!

[The Romulan Republic]

Ooh, that's an interesting idea. We see at Endor that a shield can be projected to surround a large object (namely the second Death Star), so why not use that as a siege tactic to blockade a world?

On the other hand, perhaps it wouldn't work. Don't full planetary shields usually have multiple emitters? Perhaps their's a size limit for projecting a shield like that. After all the second Death Star wasn't full-planet-sized.

On the other hand, I don't see why you couldn't project multiple overlapping shields from orbital siege satellites.

[Lord Revan]

Ooh, that's an interesting idea. We see at Endor that a shield can be projected to surround a large object (namely the second Death Star), so why not use that as a siege tactic to blockade a world?

On the other hand, perhaps it wouldn't work. Don't full planetary shields usually have multiple emitters? Perhaps their's a size limit for projecting a shield like that. After all the second Death Star wasn't full-planet-sized.

On the other hand, I don't see why you couldn't project multiple overlapping shields from orbital siege satellites.

The Empire did exactly that on Naboo in one the EU comics (this being an imperial-era comic not clone wars).

[Galvatron]

The Empire did exactly that on Naboo in one the EU comics (this being an imperial-era comic not clone wars).

Do you mean Operation: Cinder?

[Lord Revan]

The Empire did exactly that on Naboo in one the EU comics (this being an imperial-era comic not clone wars).

Do you mean Operation: Cinder?

yeah that would be it I think, sure it's not exectly using a shield to block a planet but close enough.

[Galvatron]

It also occurred to me that Darth Vader may have been most useful as a one man agent of regime change. How many costly battles may have been avoided by simply dispatching him on a "diplomatic mission" to some of the more intractable worlds?

This is more or less what he did on Shu-Torun in the new EU comics.

[Sea Skimmer]

Rebels show us that TIE fighters have obscene maneuverability, flying slowly and using their anti-grav stuff they can even fly sideways like helicopters (though of course in combat situations this might be hard due to enemy weapons fire). Rogue One's deleted scenes also show Jyn having a face to face encounter with a possibly hovering TIE.

So I wonder how TIE spam for close and REALLY close air support would work for the Imperials.

The only distinction in ground vehicle-helo-aircraft-ship is cost and size basically. A TIE fighter might not be great for CAS though because it seems to be borderline vulnerable to handheld weapons. If you flew around in peoples face's you'd start loosing them. They for example become vulnerable to land mines at that point! That's bad against insurgents.

That's probably a lot of the point of having TIE bombers and the Y-wing besides just pure aerospace superiority fighters. They've got more armor besides having shields, so they aren't just screwed from random fire connecting.

The idea ground combat vessel would probably hold about 25-50 men, with two to four turbolasers that can knock out any plausible enemy tank or reinforced building, but not necessarily all fortifications. An ISD can just blow that stuff up. A Mobile Air Assault Vehicles like this could just fly around destroying anything it saw, while also able to instantly to land enough men to suddenly raid a large building or other strategic point. You go around sucking up everyones wifi and the moment you get intel you either blow that spot up, or seize a prisoner ect..

Any smaller group of dismounts is kinda screwed on being able to physically cover ground if they land. Any larger group and you probably want to land it at multiple points further apart then the size of your ship. That's a job for multiple vehicles. You could use TIE shuttles from fleet in orbit for large scale reinforcements of just foot mobile infantry to further expand any landing you did make. But that would come with some kind of time delay. Course we don't know how expensive stuff like TIE fuel ends up being when you have millions of them, it might be important to have more troops on the ground at which point battalion transports make sense.

Big ships can always provide fire support with relatively small guns if you want to avoid area bombardments.

[Elheru Aran]

The idea ground combat vessel would probably hold about 25-50 men, with two to four turbolasers that can knock out any plausible enemy tank or reinforced building, but not necessarily all fortifications. An ISD can just blow that stuff up. A Mobile Air Assault Vehicles like this could just fly around destroying anything it saw, while also able to instantly to land enough men to suddenly raid a large building or other strategic point. You go around sucking up everyones wifi and the moment you get intel you either blow that spot up, or seize a prisoner ect..

So, a LAAT?

[Sea Skimmer]

It also occurred to me that Darth Vader may have been most useful as a one man agent of regime change. How many costly battles may have been avoided by simply dispatching him on a "diplomatic mission" to some of the more intractable worlds?

This is more or less what he did on Shu-Torun in the new EU comics.

Oh I'm sure that's huge. The problem is look at earth and all its countries. Now consider all the star wars planets that have 100 species of alien on them for added political complexity, even Naboo was not a unified government except at the republican senate level. The problem isn't making the planetary level government bow down to the Empire, its making the populations obey the government at all if its a giant evil empire going out of its way to be a dick on a Galaxy wide scale. Masses of people aren't rational when it comes to opposing things they don't like. The constant risk for the Empire would be destablizing places so government just breaks down to lower levels. The economic hit this creates for the Empire would be high. Can you imagine Imperial tax collection problems?

That raises a new question too, once the Empire got going how much of it was even funded by taxes, and how much was the Empire directly controlling automated mining and manufacturing plant that could build Death Stars? Once the Sith had enough scale of personal power, did the planets really even keep mattering? The Emperor might have been mad to the point of planning to kill EVERYONE eventually even.

So, a LAAT?

That's standing room only. I mean a ship that can actually carry its crew and infantry around full time, though probably not for longer then 3-7 day shifts. The LAAT also seemed extremely vulnerable just about any vehicle scale weapon that exists in the universe, while I would envison Imperial occupation-army eradicator ships as a lot better protected. More like AT-AT scale or higher. Back in the old WEG stuff they had a Imperial survalliance ship kind of like this, though it was armed fairly lightly.

[Elheru Aran]

So, a LAAT?

That's standing room only. I mean a ship that can actually carry its crew and infantry around full time, though probably not for longer then 3-7 day shifts. The LAAT also seemed extremely vulnerable just about any vehicle scale weapon that exists in the universe, while I would envison Imperial occupation-army eradicator ships as a lot better protected. More like AT-AT scale or higher. Back in the old WEG stuff they had a Imperial survalliance ship kind of like this, though it was armed fairly lightly.

So, basically a small warship, you're saying?

The LAAT was pretty much capable of what you described in your post, and with using an Acclamator or Venator (or hell, even an ISD) as a mobile base, they wouldn't need long-range capability-- they can just return to their ship.

[Galvatron]

Does it make any difference that both Rebels and Rogue One have shown us that ISDs can maintain a stationary position above the surface of a planet at a low altitude? In the old EU, this was supposedly impossible for ISDs and was a feature that the Victory-class remained useful for.