If both sides have troops left at the end, the invasion will continue the next turn, until one side completely runs out. Each side also chooses a battle tactic, which affects their Manpower Deployment Limit, troop health and damage, collateral damage to population and improvements, and other factors of battle.
The deployed manpower is converted into troops according to each empire's troop distribution rules and the cost of each troop type, and then each does damage to the other in multiple phases, similar to a fleet battle. Manpower Deployment Limit can be increased by the attacker having sieging fleets with appropriate support modules (such as OpEx Gear) or the defender having various System Improvements (such as Impervious Bunkers). Having more manpower than your Deployment Limit does not make the battle go any faster, it just ensures you have reinforcements for future turns. They can even return to a friendly system, refill their manpower, then drop off more at the invasion site if it's still going on! However, if all hostile fleets leave the system (so it is no longer under siege), it can refill its Defensive Manpower from the Empire Manpower.Įach turn, the attacker and defender both field a certain amount of their banked manpower, according to each one's Manpower Deployment Limit. Once an attacker has deployed their manpower, their fleets have no further direct effect no siege damage is done while an invasion is in progress, and the invasion will continue on its own. Similar to sieging, fleets can only begin an invasion if there are no hostile military ships orbiting the same system. This battle will continue until either side has lost all manpower or surrenders. Your fleet will immediately deploy its entire manpower stock to the surface and a ground battle will begin.
Once a system's defenses have been sieged down to your liking, use the Invasion action while your fleet is in orbit to start a ground battle. This may or may not be useful depending on the faction you're playing, but it could make them cheaper to field. ℹ️ Note that, unlike many modules, it's legal to equip siege modules on civilian ships, like colony ships. If that's all they have, they'll end up near enough to zero to immediately give you a "Decisive Victory", and prevent the trench warfare from ruining the system. However - if you first siege the system down to zero manpower, the number of troops raised by "Draft" is something that a reasonably modern/upgraded assault force can often kill outright in a single turn, especially with a Blitz strategy. Any attempts to turn up the heat with more aggressive battle tactics only make the destruction worse, as the system depopulates and loses buildings. On each turn, a defender can issue a "Draft" strategy, and replenish enough manpower to keep on fighting, turn after turn (potentially for a few dozen turns). The second reason is that the developers mindfully set up the numbers so that sieging can be used to opt out of a "death spiral" that frequently happens when assaulting a system the enemy truly does not want to lose. killing populations or system improvements), unlike most types of invasion strategies. The first reason for this is that sieging, itself, does no "collateral damage" whilst in progress (i.e. Blockade enemy civilian ships to destroy them for dust.
To prevent enemies from producing strategic/luxury resources and halve their economic progress.Done right, it let you conquer a system with minimal damage to what is about to become your system.Larger ships, more weapon modules, or some support modules can increase the amount of lost each turn. ℹ️"Hostile" here means either the two empires are at War, or they're in Cold War with the besieger having the "Righteous Fury" Religious automatic law, or they're in Cold War with the defender's system being within the besieger's cultural boundary, or the defender is an always-hostile minor faction like Pirates. While a system is sieged, it can't refill its, send or receive any civilian ships, or produce any strategic or luxury resources for the empire. If a hostile fleet orbits an enemy system with no other enemy fleets distracting them, they automatically lay siege to the system, reducing the system's defensive manpower every turn.