Atarlost

Well-known member
A gigaton is a very big nuke. Tsar Bomba with its uranium tampers as originally designed would be a tenth that size and it was 27 tons. Assuming the number of stages required relates to the logarithm of the explosive power a gigaton nuke would need to be a six stage device.

A nuke that doesn't get through the armor, which will be not quite half the radius of Ceres in thickness, doesn't accomplish very much so if you use multiple smaller nukes you need to land all of them in the same location. The smaller your nukes the easier they are to knock off course enough they don't land in the same crater. The larger they are the easier they are to hit with enough firepower to disable them. Nukes are fragile and are reduced to squibs if damaged. If you armor your missiles that makes them larger and harder to carry in sufficient numbers or at all if your sufficient number is one. There may be a balance that works, but the tyranny of the rocket equation is not your friend. You've picked an example that isn't really assailable by any method

There's a point in civilization capability where stelasers and combat mirrors dominate space combat unless you're deep in clarktech. Clarktech throws all of your assumptions out the window and the limits of weapons and forcefields are tailored to the needs of the plot or game balance. Without force fields an armada isn't getting close to anything the party holding the low solar orbits wants to defend without permission. And if you don't have Clarktech beyond just FTL I suspect stelasers and war mirrors become dominant before you get non-sail propulsion that can move around that sort of firepower. This isn't even a MAD case, it's absolute dominance of the defense until civilizations move from "well over K1" to "definitely K2" and start threatening each other with Nicol-Dyson Beams, though at that level of infrastructure star systems can dodge if FTL gives them some means of knowing they've been attacked before the light arrives.

In fact the real question is what role space fleets have in an interstellar setting?. If we go with the standard minimally intrusive distant jump points of hyper limit FTL model or a war of methusalehs or AIs for whom a few decades of STL transit between stars is a tolerable journey he who controls the low stellar orbits controls the star system the way the most optimistic orbital supremacy models give the orbitals control of planets. You need Clarktech that either allows you to shield against weapons powered by the biggest fusion reactor in the system, maneuver energetically and continuously to avoid light speed beams and your missiles to outmaneuver you, or in-system FTL that is otherwise constrained in such a way that it doesn't prevent combats from happening.

And once you're writing Clarktech into your setting beyond the bare minimum unobtrusive FTL you can craft the interactions to produce whatever dominance of ground or space power you want. Or stick to minimally intrusive FTL and have a setting where economic power dominates because attacking any system with developed infrastructure is a useless gesture.
 

Bear Ribs

Well-known member
You might just want to destroy what's on it, at which point "nuke 'em till they glow" is an entirely reasonable course of action along the lines of a strategic bombing raid.

Suppose it's something the size of Ceres and a major source of enemy starship components. A gigaton Ka-Boom will do unkind things to whatever's on the surface and the enemy's ability to keep their fleet operational.
The problem with this is that the enemy knows this too, so there're really only three possibilities:

1: They've emplaced sufficient defenses (the manufacturing center is likely a kilometer or two deep inside the asteroid and will ignore your gigaton ka-boom) that you'll lose more trying to destroy Ceres than you're likely to inflict on them.
2: They did not place their major manufacturing on such a vulnerable asteroid.
3: They're so freakin' stupid you probably don't need to attack it in the first place as they're going to be losing everywhere else and you can capture it easily.
 

BlackDragon98

Freikorps Kommandant
Banned - Politics
I surprised no one has mentioned the potential for "Rods from God" type weapons to replace nukes as a bombardment option, given they don't cause any radioactive mess.
 

The Whispering Monk

Well-known member
Osaul
I surprised no one has mentioned the potential for "Rods from God" type weapons to replace nukes as a bombardment option, given they don't cause any radioactive mess.
I did but I wasn't clear on the point. C-fractional kinetic strikes from powered missiles. Kinetic energy will cause so much more damage at that speed than the nuke/whatever will. Unless you want to go the "Anti-matter" warhead used on a planet.
 

Doomsought

Well-known member
It will have a better penetration factor, but I doubt it would have the same area denial capability. Kinetic perpetrators have a problem with over-penetration. Unless you design the impactor for a meteor air burst, most of the kinetic energy would be wasted on subsurface rock formations. It would be great for bunker busting at least.

Nuclear weapons have a similar issue once you get into the hundreds of megatons, where the blast wave will be reflected off the surface of the planet and most of the energy will be wasted throwing atmospheric gases into space. This is incredibly inefficient, so you are better off using MIRVs than biggatons.
 

The Whispering Monk

Well-known member
Osaul
All I know is that, at this level of energetic transfer, dead is dead.

We're just theorizing the results of said weapons.

For all I know a kinetic penetrator that has the potential to go THROUGH the crust into the mantle may result in such an intense shock wave that global earthquakes begin and all the volcanoes go off.
 

BF110C4

Well-known member
Going back to the actual roles of the ground forces in a planetary invasion. If the Planet to Space defenses are too strong for a bombardment to counter and the enemy doesn't have resourses for an absolute coverage of the entire planet then having the equivalent of a MEU available to do a landing in an undefended area and fight its way to the closer planetary cannon (or missile battery, or laser, or satellite control node, or...) is a valid strategy as long as the enemy's forces cannot overwhelm you with superior numbers.

The planet's always got superior numbers than a reasonably sized invasion force, at least for a few waves but they need to protect a lot more terrain and a MEU can choose their landing area at will so they have tactical surprise, they come as a single, usually comparatively heavy assault unit with disproportionate firepower to their size and composition and the moment they manage to degrade a defense grid enough their own ortillery will give covering fire at will.
 

The Whispering Monk

Well-known member
Osaul
Yup, have to be able to access a beachhead, land on it, then reinforce it enough to be able to hold it for follow on forces. I'm thinking you'd need LOTS of ground based AA (for both anti-air as well as anti-bombardment) as well as heavily dug in armored forces.
 

BF110C4

Well-known member
Yup, have to be able to access a beachhead, land on it, then reinforce it enough to be able to hold it for follow on forces. I'm thinking you'd need LOTS of ground based AA (for both anti-air as well as anti-bombardment) as well as heavily dug in armored forces.
Geography is also important. For a planetary invasion I'm a partidary of starting with large islands close, but not too close to continents like Japan or England. For a space based invasion force the traditional defensive advantage of large bodies of water is meaningless and the isolation means that once you have cleared the orbital defense grid in that sector your ortillery can neutralize any counter invasion force trying to cross the ocean with ease, the size of those places make easy to disperse your bases to prevent a surprise nuclear cruise missile on any particular location and with some luck and compatible biology there is enough fertile land and other resources to ease your logistics.

My second objective are large landmasses with obvious bottlenecks and not enough population or infrastructure to be a high priority in their defense. Land a blocking force on Panama for example and you cut the continent in half, with the added bonus of the Pacific and Atlantic fleets unable to link with each other. Same with cutting Italy from the rest of Europe.

Even if you don't actually hold vital ground those land grabs will unnerve the local leadership forcing, at least initially, to perform costly counterattacks and redirecting resources from other potential targets.
 

*THASF*

The Halo and Sonic Fan
Obozny
Irregular forces and guerilla warfare are still valid even if the enemy controls orbit. There may be infrastructure or population centers that they don't want harmed and cannot strike from orbit as a result. In other words, a clever ground force in an interstellar fight would use terror tactics, fight out of uniform, use urban areas as human shields, et cetera.
 

Doomsought

Well-known member
gland. For a space based invasion force the traditional defensive advantage of large bodies of water is meaningless and the isolation means that once you have cleared the orbital defense grid in that sector your ortillery can neutralize any counter invasion force trying to cross the ocean with ease, the size of those places make easy to disperse your bases to prevent a surprise nuclear cruise missile on any particular location and with some luck and compatible biology there is enough fertile land and other resources to ease your logistics.
Submarines with cruise missiles are a huge threat to a planetary invasion force because they can have a large tonnage of weaponry while avoiding orbital surveillance.
 

BF110C4

Well-known member
Submarines with cruise missiles are a huge threat to a planetary invasion force because they can have a large tonnage of weaponry while avoiding orbital surveillance.
True, that's why I'm partly in favor of large islands, some additional miles between the beach and your foward operation's base means more time and better locations to intercept any pesky nuclear missile.
 

The Whispering Monk

Well-known member
Osaul
Submarines with cruise missiles are a huge threat to a planetary invasion force because they can have a large tonnage of weaponry while avoiding orbital surveillance.
Now you just need Aquatic HK Drones to go hunt subs, OR you can go the boring manned route.
True, that's why I'm partly in favor of large islands, some additional miles between the beach and your foward operation's base means more time and better locations to intercept any pesky nuclear missile.
Can just take some nice wide open plains in the middle of a continent. Less likely to be ambushed by underwater missiles that way, and you can still control wide swathes of ground with the kind of weaponry we're proposing.
 

BF110C4

Well-known member
Can just take some nice wide open plains in the middle of a continent. Less likely to be ambushed by underwater missiles that way, and you can still control wide swathes of ground with the kind of weaponry we're proposing.
It would really depend on the planet's geography, the actual strategic objectives and the resources available to provide ortillery. Ler's take for example Vietnam's Ho Chi Minh trail, it was a ground route which despite an interdiction campaign launching an average of a bomb every seven minutes managed to move entire divisions worth of materials and soldiers, and while its the greatest example of that in modern history there are many more instances of large military forces being assembled and supplied despite overwhelming vigilance and interdiction efforts.

Trying to stop a Ho Chi Minh effort with a space fleet is actually harder than it sounds, with ideal terrain just giving the illusion of safety, the enemy would just gather in the nearby forested or mountain regions and slowly gather strengh until they can act openly, creating a Diem Bien Phu trap. And interdicting roads is always hard, especially if you lack enough boots in the ground to secure the roads; satellites can detect trafic, but a canny enemy will disguise their movements with the civilian trafic (who would also be supplementing the soldiers with food and board), artillery and vehicles can be diassembled and then reassembled on the target area and dispersing the troops on the local population can hide preparations.

Also bombarding their supply lines is putting the logistics of a planetary based force against a spaceborn one, which means your ships would need to keep station, which takes energy and therefore fuel and constantly bombard multiple roads once again costing lots of ammunition for no clear advantage. On the other hand on the sea the ability to move large amounts of personnel is limited by the craft available, and the ships themselves are more vulnerable in the middle of the ocean, bomb a truck carrying supplies in the trail and the porters will salvage what they can and wait for the next truck to arrive to take things to their final destination, bomb a ship and their cargo goes to the botton of the sea while the enemy loses permanently the cargo capability of the ship, therefore flipping the cost-benefit equation to the spaceborne forces.
 
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The Whispering Monk

Well-known member
Osaul
Trying to stop a Ho Chi Minh effort with a space fleet is actually harder than it sounds, with ideal terrain just giving the illusion of safety, the enemy would just gather in the nearby forested or mountain regions and slowly gather strengh until they can act openly, creating a Diem Bien Phu trap.
That's going to depend on how much the denuding of the planet the aggressor force is willing to do. Obliterate a few forest around your beachhead...might be an OK decision.
 

BF110C4

Well-known member
That's going to depend on how much the denuding of the planet the aggressor force is willing to do. Obliterate a few forest around your beachhead...might be an OK decision.
Diem Bien Phu had the attackers dig a surprisingly sophisticated trench system that included protections for their artillery, and with modern weaponry the range to raze increases dramatically. Imagine the planetary forces carrying piece by piece a hundred mid-range rockets with FAE warheads to overwhelm in a single barrage your big base in the middle of the siberian steppe, and to add insult to injury they use the stil hot forest fires and the smoke they generate to cover the initial barrage. At the same time and a hundred miles around you other units have assembled semi-mobile ASAT launchers to prevent the arrival of support shuttles while they move their own light infantry battalions in civilian trucks to overwhelm isolated outposts.
 

Allanon

Well-known member
I would imagine, since even now we can launch nukes from orbit and devastate a planet, is to hold captured positions on worlds we do not want to annihilate.
 

Husky_Khan

The Dog Whistler... I mean Whisperer.
Founder
Sotnik
A lot of ground combat in sci-fi is kinda unrealistic because you'd need hundreds of millions minimum to garrison a force and routine reinforcements due to insurgency and rebellion unless you know you do genocide.


40k and Star Wars is like here's a thousand or a million guys go get em kiddo and that's it.

One of the plus sides of Warhammer 40K is that it does sometimes try to feature the scale of galactic wide conflict. Isaac Arthur, the YouTuber mentioned in the starting OP, actually commented on that concept in one of his videos IIRC.
 

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