Taking a Gravity Well is the easy part. A fleet jumps in, clears out whatever resistance is there, and for a moment the space is yours. But empty space doesn't win wars. What you do with a Gravity Well after you take it is where the strategy lives.
The Major Structure Slot
Every Gravity Well in The Outer Line has one slot for a major structure. One. You pick a chain: Military Station for defense, Mining Station for economy, or Shipyard for production. They're mutually exclusive. If you build a Mining Station, you can't build a Shipyard or Military Station in that same Gravity Well. If you build a Military Station, no Mining Station, no Shipyard.
This is the decision that defines every Gravity Well you control. Each one becomes a fortress, a mine, or a factory - never all three. Smaller structures like Academies, Supply Nodes, Listening Posts, and Defense Platforms are free and don't use the major slot. But the big choice, the one that shapes how that Gravity Well fits into your strategy, is always one pick from three.
I think this is one of the strongest design decisions I've made so far. I hope it plays as well as it reads on paper.
Supply Nodes and Mining Stations
The economy starts with asteroids. You build Supply Nodes on them, and each one generates Supply passively. A Gravity Well with dense asteroid fields can support a lot of Supply Nodes. One with sparse rocks gives you less to work with.
The Mining Station amplifies this. It boosts the output of every Supply Node in the same Gravity Well by a percentage. It doesn't produce anything by itself, so building one in a Gravity Well with two asteroids is a waste. But in a resource-rich Gravity Well with a dozen viable asteroid positions, a Mining Station turns a decent income into a serious one.
The trade-off is real, though. Building a Mining Station means that Gravity Well can't have a Shipyard or a Military Station. You're betting that the economic boost is worth more than local production or heavy defenses. If the enemy raids your best mining Gravity Well and you don't have a Military Station there, you'd better have a fleet nearby.
This is one of the things I like about how the map types interact with the economy. An Industrial Gravity Well has lots of asteroid density, which makes the Mining Station extremely valuable there. A Frontier Gravity Well has average resources, so the boost matters less. The map tells you where your economic backbone should go, but the enemy can read the same map.
Shipyards and distributed production
The Mobile Shipyard builds ships. But it's one ship, in one place, and if you're fighting on multiple fronts, reinforcements from a single location take time to arrive. That's where stationary Shipyards come in.
Shipyards upgrade through three tiers. Tier I produces light ships, Tier II adds medium classes, Tier III unlocks heavy production. Each tier replaces the previous one, so you're upgrading a single structure, not building new ones.
Having a Shipyard in a Gravity Well near the front means fresh ships arrive faster. Having one in the rear means safer production but longer travel time. Of course, choosing a Shipyard means that Gravity Well won't have a Mining Station or Military Station. Shipyards do have light self-defense weapons - enough to chase off a frigate or two, but not enough to hold against a real assault. A forward Shipyard still needs fleet protection. A rear Shipyard in a resource-rich Gravity Well means you're leaving economic potential on the table. Every placement is a trade-off.
I've been going back and forth on whether Shipyards should be able to produce the same range of ships as the Mobile Shipyard at equivalent tiers, or if they should be slightly more limited. Right now they mirror the MS, but that might make the MS feel less special. Something to figure out with testing.
Military Station
This is the big one.
The Military Station is the toughest structure you can build. High HP, defensive weapons, sensor coverage for the Gravity Well. It's expensive and takes a while to construct, but once it's up, taking that Gravity Well from you becomes a real problem for the attacker. You can't just fly through and ignore it.
Since it uses the major structure slot, building a Military Station means no Mining Station and no Shipyard in that Gravity Well. You're sacrificing economic or production potential for raw defensive power. That's a big commitment, and it only makes sense in Gravity Wells where holding ground matters more than generating income or building ships.
The Military Station doesn't factor into the victory condition - you lose when all your Mobile Shipyards are destroyed, not your stations. It's purely a defensive tool. But a Military Station in a key Gravity Well makes the enemy's life much harder. They can't just raid your supply lines when there's a fortress watching over them. And if you're trying to protect your Mobile Shipyard, parking it behind a Military Station is one of the safest plays you can make.
I'm still working on getting the HP and firepower right. Too strong and attacking feels impossible. Too weak and there's no reason to build them over just parking a fleet there. The current balance leans toward "strong enough to hold against a small raid, but a real assault force will eventually break through." Whether that's the right spot, I honestly don't know yet.
Capital Shipyard and Academy
The Capital Shipyard is the top of the Shipyard chain - Tier IV. You can only build it in a Gravity Well that already has a Shipyard III, and it replaces and upgrades it. Once built, it produces capital ships and new Mobile Shipyards. Getting there is a serious investment: you need to progress through three Shipyard tiers first, all in the same Gravity Well. Losing that Gravity Well hurts in a way that losing an empty one doesn't.
The Academy is quieter but arguably just as important. It increases your global Command Point cap, which determines how many ships you can field. More Gravity Wells with Academies means a bigger fleet. This is one of the incentives for expanding rather than turtling in two or three positions. If you want a bigger fleet, you need more Academies, which means you need more Gravity Wells, which means you need to push outward.
The enemy knows this too. Raiding an Academy in a lightly defended Gravity Well shrinks your opponent's fleet cap without having to fight their main force. I've seen the AI do this in testing, actually. Jump in, destroy the Academy, jump out before the fleet arrives. Effective, annoying, and exactly the kind of thing I want the game to allow.
Listening Posts and the edges
Not every structure is a big investment. Listening Posts are cheap, fast to build, and extend your sensor range. Drop one at the edge of a Gravity Well and you'll see enemies charging their Jump Drives from further away, buying you extra seconds to react. They die quickly if attacked, but they're cheap enough to replace.
I tend to scatter them at the borders of Gravity Wells I care about. The information they provide is worth more than their cost almost every time.
The question I keep asking
Every time I look at the structure system, I come back to the same thing: which major structure belongs in which Gravity Well? A resource-rich Gravity Well near your core probably wants a Mining Station. A Gravity Well on the front line might need a Military Station. A safe rear Gravity Well could be the best spot for your Shipyard chain. But the map doesn't always make it obvious, and the enemy's movements can change everything. I think the answer is "it depends," which is where I want it. I hope the trade-offs feel meaningful in practice and not just on paper.
Next devlog covers the thing that makes all these decisions harder: Fog of War. What you don't know can absolutely hurt you.