Collateral Damage

General
All base modules inflict damage to all adjacent modules upon destruction, this includes modules directly north, south, east, west as well as diagonally. The damage they inflict varies greatly, see specific pages on the base modules for the exact amount of damage they deal upon destruction.

Collateral damage forces the base defenders to spread out their combat modules, particularly away from other high level combat modules and especially away from the bridge or the fleet bay as those tend to have very high amounts of collateral damage.

Collateral damage does not damage ships, squadrons, wings or Terminus mines. Heavily damaged, compact bases still repairing after battle or bases with low armor can be destroyed quickly as collateral damage can set off a chain reaction of explosion, destroying large portions of the base at a time.

Alien outposts have two modules that deal noticeable collateral damage to adjacent modules: the Alien Energy Capacitor and the Alien Citadel, which makes destroying them the key to demolishing the Outpost efficiently. Unlike in player bases, the collateral damage in Alien Outposts affects modules up to 2 diagonal squares away instead of 1.

Mining Outposts have three modules that deal significant collateral damage to adjacent modules: the Solar Shard Storage, the Solar Special Module and the Solar Bridge. Targeting these modules is the key to destroying the Outpost within a single battle. With the exception of the Bridge (3) and Special Module (4), the collateral damage in Mining Outposts affects modules up to 2 squares away.

Official Information
According to what Kixeye CM CarterGee said on the offical update thread :

"Base modules have large amounts of energy passing through them to keep them functional. During combat as modules are destroyed, explosions occur that can affect nearby modules. As a rule, the higher a module’s base health the more energy it requires to keep operational, resulting in heavily fortified combat modules being particularly volatile. It is intended that players adopt new strategies for base layouts to avoid potentially disastrous chain reactions if their opponent breaches their defenses.


 * Collateral damage is considered untyped damage, therefore it cannot be resisted by any means.
 * Damage only affects modules directly next to the destroyed module.
 * Damage is dealt on a per module / level basis.
 * Adding shields or armor will not result in a bigger boom, but modules with a higher base health like the Ship Factory will cause more damage than a resource miner. Within each module, click “Manage” to view collateral damage.

Trivia

 * Upon introduction, collateral damage was met with negative feedback.
 * In the current meta, collateral damage doesn't matter very much, given that most high-level ships are able to quickly destroy entire bases single-handedly, whether the modules are closer to each other or not doesn't matter much anymore.