Over in the thread about Adam aka Admiralducksauce’s ‘Throne of Glass and Shadows’ game, we got into a discussion about space vs. ground operations that turned into trying to Tech Burn some kind of fortress that could actually give you a fighting chance against enemy Hammer.
Clearly this is something that Chris Moeller himself has some thoughts about, since he describes Hotok (in Faith Conquers) as a “fortress world.” Geil Caracajou says “it’s mostly underground,” and Trevor Faith goes into more detail:
“The keep… its chamber and bunkers stretch for kilometers in all directions, stitched to the main power sink by cables and grid channels. Clouds of smoke heave from its spires like black pennons in the wind – and at its center-beams sit in their armored silos, ready to scourge the heavens.”
(And that’s all the nitpicky canon-quoting you’ll get from me. I ain’t no frickin’ Trekkie.)
Now, defending against an enemy with space superiority is terrifyingly hard (as Chris Moeller himself points out here). In particular, Hammer is always, always going to have superior maneuverability compared to anything on-planet, let alone a stationary fortification: Spacecraft can engage and disengage at will, they have the high ground automatically, and if they get fed up, they can always find a nice asteroid somewhere, nudge it towards you, and let gravity take care of the rest. (Yeah, maybe you can blast the first asteroid off-course. Groovy. But there’re plenty more drifting space rocks where that one came from, and it doesn’t take much mass hitting the ground from 1,000 miles up to make a big hole). So here’s a tentative tactical principle:
If the enemy has space superiority, and they know where you are, and you can’t move, you’re dead. No amount of weaponry, no armor, no amount of digging underground, is going to do anything more than buy you time.
I say “tentative” tactical principle because it’s conceivable that waste heat is such a terrible limiting factor on space-born weapons systems, and that a ground-based heat-sink can be so obscenely huge, that fortresses can actually hold off a sizeable Hammer attack by sheer superior firepower. It’s conceivable, but a stretch, for me at least.
Why? Here’s the Hammer’s advantage: Mobility. Here’s the planetary fortress’s advantage: Mass. Every kilogram a spacecraft carries is precious and expensive; on a planet, mass is literally dirt cheap – and even dirt is a good defensive barrier if you have enough of it (read any book on trench warfare). Mass is your shield and, if you use it for heat sinks, a big help to your sword as well. But ultimately, mobility is going to win, because mobility can always dance out of harm’s way and find all the mass it wants, namely those pesky asteroids: Hammer can just drop rocks on your head, or get fancy and set up “siege guns” on asteroids using a planetoid’s worth of mass for heat sinks.
So using your planet’s mass for armor, or even using it for heat sinks for bigger weapons, will fail you in the end – although it may be adequate to repel anything short of an all-out invasion, making the heat sink plus gun turret type of fortress viable to a point. But there’s a third way of using mass: to hide.
The model for a planetary fortress isn’t a medieval castle, or even the Western Wall that the Germans built to defend the coast of France in World War II. It’s Cu Chi, one of the most elaborate tunnel systems – seventy-five miles long! – built by the Viet Cong. If a bunch of undernourished rice farmers with hand tools can build defenses sufficient to stymie the United States military, the engineers of the Iron Empires can build ones sufficient to baffle the Vaylen.
Now, what you hide in these tunnels isn’t just infantry in black pajamas. My (re-)interpretation of those big, squat artillery batteries that Trevor Faith walks past at the Hotok Keep is that they’re not actually gun turrets at all, but giant self-propelled artillery pieces parked and waiting for war.
When enemy Hammer shows up in orbit, the SP guns duck into the tunnel system and hide. Sure, the Hammer can locate and blast some of the tunnel entrances, but they won’t get them all. Convincing decoy tunnel mouths are easy to build – especially if the construction crews aren’t too sure where exactly they’ve been taken to work today, and whether the hole they’re digging this week is a decoy or actually going to connect to the tunnel system. Backup real exits are easy to hide: inside buildings; under water, with an airlock system (presumably, grav vehicles have to be airtight); or buried under a few tons of dirt - in fact, the tunnel could be dug from below and the exit never completed, with engineers making the final breach only when it’s time to emerge (like the “Bugs” in Heinlein’s Starship Troopers). The only way Hammer can tell a decoy entrance from a real one, let alone to find a hidden entrance, is to fly low enough, long enough to get a good look – which, given that the Iron Empires setting doesn’t give sensors a huge range advantage over weapons, means you’re coming close enough to shoot.
So when the scattered, hidden, and pretty disposable sensor arrays on the surface detect enemy Hammer in the right places, SP guns fly out of the tunnels, open fire, and then fly back underground – probably using a different tunnel mouth than the one they sortied from. (Modern artillerymen call such tactics “shoot and scoot”). It’s quite possible that Hammer will blast some of the SP guns on the surface; it’s almost certain that Hammer will blast some shut of the tunnel mouths thus revealed. But SP guns and tunnel entrances are cheaper than starships. This guerrilla war of attrition actually starts looking winnable.
We already have some self-propelled missile launchers and fusor cannon burned up, so the missing piece is the tunnel system itself – which was frankly stumping me. But Adam (“admiralducksauce”), Devin (“zabieru”), and Mike Atlin (“countercheck”) had a good brainstorm in the parent thread, which I’ll excerpt the relevant bits from here:
So at this point we’re trembling on the edge of a workable Tech Burn for a tunnel system, which means it’s a good time to bring it over to this part of the forum and solicit input on the final form – or forms, given that there may be several valid ways to build a fortress.
I’m finding it hard to comment on how close your fortress is to the book, though, because I haven’t read Iron Empires yet. The point cost seems reasonable, though - there’s not much that can turn an artillery battery into just an Injured result for a human.