Combat occurs when one fleet encounters another as the result of an Attack. The attacker's ships immediately fire on the defender's ships and defenses, if there are any. If the attacker destroys all ships and defenses, and still has cargo space available, plunder will occur.
How it Works
Combat lasts until either the attacker's or defender's forces are completely destroyed or six rounds of combat take place. In each of the rounds, all of the attacker's and defender's units fire randomly at the opposing fleet's units simultaneously. If any unit strikes a unit against which it has Rapid Fire, that unit will get a chance at firing an extra shot, also randomly. This will repeat until all units fail on their random Rapid Fire chance or hit a unit against which they do not have Rapid Fire.
The damage dealt from each shot is equal to the shooting ship's Weapons Rating. So for instance an Artemis Fighter has a Weapons Rating of 50. If it hits an Atlas Cargo it will deal that Atlas Cargo 50 damage.
Shield and Hull
Damage done to a ship in each round is first absorbed by that ship's Shield Rating and then the remaining damage subtracts from the ship's Hull Rating. An Atlas Cargo has a Shield Rating of 10 and a Hull Rating of 400, so if it were shot by an Artemis Fighter, which deals 50 damage, the first 10 would be absorbed by the shield and the remaining 40 would reduce the Atlas Cargo's hull to 360.
Shields replenish between rounds but Hull does not repair until the end of battle. So in our example above, in round 2 the Atlas Cargo would start with 10 Shield again and only 360 Hull. After round 2, if it survived, it would have a Hull of 320.
Any strike from a ship with a weapon rating which is less than or equal to 1% of the shielding capacity of the target is absorbed with no effect on the target. As an example, suppose a player with a Weapons Tech of 12 attacks a player with a Shield Tech of 9, and in the battle one of the attacker's Artemis Fighters targets the defender's Large Decoy. The fighter would have a weapon rating of 110 (50 + 5 * 12). The Large Decoy would have shield rating of 19,000 (10,000 + 1,000 * 9). Since 110 is less than 190 (1% of 19,000), the Artemis Fighter would do no damage; that shot is ineffective. Furthermore, it is essentially impossible that an attacker could research their Weapons Tech high enough that an Artemis would ever damage a Large Decoy. However, some units have base weapons ratings which are equal to 1% of other units' base shield ratings; in these cases the respective weapon and shield tech levels come into play.
Shots against the following units are always effective (base shield less than 100): Missile Battery, Laser Cannon, Hermes Probe, Helios Solar Satellite, Atlas Cargo, Dionysus Recycler, Hercules Cargo, Charon Transport, Artemis Fighter, Apollo Fighter, Poseidon Cruiser.
Defenses have relatively high weapons ratings; their shots are effective against all attack ships, with the exception that “fodder” defenses (Missile Battery, Laser Cannon, Pulse Cannon, and Particle Cannon) are ineffective against Zeus.
For other pairings, consult the following table:
At the end of each round, when all ships are done firing, any ship that has less than 70% of its initial Hull Rating has a chance to explode equal to the total hull reduction.
So in our above example after round 4 the Atlas Cargo will have suffered 160 total Hull damage and have 240 Hull (out of its starting 400) left. That means it has lost 40% of its Hull ((160/400)*100) and will therefore have a 40% chance of being destroyed.
If it survives, at the end of round 5 it will have suffered another 40 Hull damage for a total of 200, giving it a 50% chance of destruction. At the end of round 6 it will have suffered 240 Hull damage and have a 60% chance of destruction. Thus it is actually possible for an Atlas Cargo to not be destroyed by an Artemis Fighter.
At the end of combat if all of the defender's ships and defenses have been destroyed, and the attacker has ships remaining, the attacker will have won the battle and will Plunder the defender's planet.
At the end of combat if all of the attacker's ships are destroyed, and the defender has ships or defense remaining, the defender will have won combat. No Plunder will be received by the attacker.
If at the end of combat both sides have ships left, or all ships have been destroyed, the battle will have been a draw and no Plunder will be received by the attacker.