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While most of Stellaris' combat takes place between fleets of advanced starships, an inhabited system cannot be secured by an attacking empire until its planets are occupied. This requires a planetary invasion, sending millions of ground troops to seize control of the world. A well-executed invasion can easily occupy a planet, while a bad one is an expensive mistake.
Whether your troops are humanoid, robotic, insectoid, or any of the many species types available in Stellaris, having a grasꦉp of the ground combat system will help keep them alive. Read on to become a space-age Sun Tzu!
How Orbital Bombardment Works
Before sending in your ground troops, most planets will need to be softened up with an orbital bombardment. This is done by moving one or more fleets to orbit the target planet. The ships will continuously degrade the planet's defenses over time as long as they remain in orbit and are not interrupted by combat. Larger fleets deal more damage, up♛ to a maximum fleet size of 200. Fleets larger than 200 do not gain any additional bonuses to bombardment.
The effects of an orbital bombardment campaign are determined by the fleet's stance, which can be selected in the fleet's window. By default, fleets use Selective Bombardment, dealing less damage to defending armies but avoiding needless civilian casual🐲ties.
Damage to a planet's infrastructure is measured in Devastation, which is expressed as a percentage from zero to a hundred. Each point of Devastation reduces most of the planet's benefits, including Housing, Amenities, and resource production, by one percent. Once Devastation reaches twenty-five percent, orbital bombardment will begin to kill pops each month.
Bombardment Stances
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Stance |
Effects |
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Selective |
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Indiscriminate |
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Raiding |
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Javorian Pox |
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Armageddon |
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"Normal damage" and "normal Devastation rate" refers to the base amount determined by the bombarding fleet's size.
How To Invade A Planet
To conquer a planet, you'll need Assault Armies. Planets generate Defensive armies based on their population and buildings, but these armies are locked to their home planet and cannot be sent to conquer other worlds. In the Armies tab of a planet, click the Recruit button to raise offensive armies. The basic type is the Assault Army, but you'll unlock many powerful new army types over the course of the game, all of which can invade enemy worlds.
Try to raise armies on planets with improvements like the Military Academy, as they'll start with more experience and be slightly stronger in the field. Also look for species within your empire who have the Strong or Very Strong traits, as armies comprised o🔯f these species will deal more damage in com🍬bat.
When an offensive army is trained, they'll appear in a transport ship orbiting the planet they were recruited from. These transport ships are vulnerable, so make sure they can safely reach their destination. Merge any transport ships you want to include in the invasion into a single fleet, or have them gather in orbit over the target world. When you're ready, select the transport fleet and right-click on the invasion target, then select "Land Armies."
It takes a few days for the troops to make planetfall, but once they do the battle will begin. Continue bombarding the planet in the meantime to give your armies support from orbit.
How Ground Combat Works
The attacking armies will engage any defensive armies the planet has, along with any offense armies who happen to be stationed planetside; if you're on the receiving end, landing Assault Armies on one of your own planets adds their might to the world's defense. Up to five armies from each side can fight at once, plus one for every five Size the planet has. Any extra armies are held in reserve and will take the place of a destroyed army as needed.
Each day of ground combat, armies will damage one another as well as reducing one another's Morale. Particularly terrifying armies, like Psionic warriors and mutant Xenomorphs, deal increased Morale damage. Armies whose Morale has been reduced to fifty percent or less deal half damage, and armies with zero Morale deal one-quarter damage. When an army's Health reaches zero, they are permanently destroyed.
The attacking army will also inflict additional Devastation on the planet as the battle g🔯oes on. Long, drawn-out invasions may result in the attacker planting their flag on a p𓂃lanet of rubble.
The attacking army may call off the invasion at any time by clicking the Retreat button on the battle window. Retreating armies may have their transports destroyed during the withdrawal, causing the loss of the army in question. The defender, on the other hand, has no choice but to fight to the death. When one side's armies are completely eliminated, the remaining armies are considered the victors and gain (or keep) control of the planet.
In all but the most desperate conflicts, a conquered planet will be occupied until it is retaken or the war ends. An occupied planet will have high levels of Resistance and isn't much use to the occupier, but you usually can't take claimed systems in peace negotiations unless you occupy them. In a Total War, a conflict where each side seeks to eradicate the other (such as wars against Fanatic Purifiers), a system's ownership changes immediately once its Starbase and all inhabited planets are occupied.
Generals
An army can be led by a General, whether they are attacking or defending a planet. Generals are assigned to a single army for transport purposes, but will grant their benefits to every army participating on their side of the battle. If multiple armies have a General, the highest-level character will take command of the entire engagement. An army deals fi෴ve percent more damage in combat per experience level its commanding General has.
Every time an army is destroyed, there is a five percent chance that the commanding General will be killed in action. A General will🃏 also die if the transport ship they are aboard is destroyed.