Unit reference costs, hull, shields, guns and Volley the simulator uses
Hull is (metal + silicon) ÷ 10 × 1.45. Weapons, Shielding and Armour each add 10% per level to gun damage, shields and hull.
Every unit has main guns and/or volley guns. Main guns aim at a random enemy unit, favouring dangerous ships (Threat); volley guns aim at a random enemy unit by numbers alone.
Volley ×N: a volley gun aimed at that type fires N shots on average (between 1 and 2N − 1). The first hits the target it picked; the rest spray across the whole enemy fleet. Below 1, some guns can't get a shot off. Defences never get Volley.
Every shot is deflected (×0.5), a hit (×1) or critical (×1.5). Shots below 1% of the target's shield do nothing.
Shields refill every round. From any one shot a shield soaks at most its Shield × that gun's share of its ship's Attack. Hull damage lasts the whole battle.
Structural failure: a unit more than 30% damaged whose hull was hit may break apart at the end of the round. The more damaged it is, and the more hits it took, the likelier.
Groups of up to 2,000 ships are fought ship by ship; bigger groups are worked out from a sample, so very large battles stay fast.
Plunder only happens when the attacker wins, and is limited by the cargo space of the ships that survive. Up to the plunder share (half, normally) of each resource can be taken, and the space is split equally between metal, silicon and hydrogen; a resource with less on offer than its equal part gives all it can and leaves its unused part to the others.
After a planet battle, each defence destroyed has a 60% chance of being rebuilt straight away (80% if the defender has a Warden). Rebuilt defences aren't losses and leave no wreckage.
PvE events: every attacking fleet fights the event fleet together, each with its own technology. Damage share is the shield and hull damage each fleet actually landed.
PvE rewards: half the wreckage is public and half is split by damage share. Pirate (and bait) loot is split by damage share, only on a win. Trader loot is split by cargo space (each fleet's counted space is capped at the event fleet's), win or draw. Loot that doesn't fit spills into the public wreckage. Ship wreckage never includes hydrogen; spilled cargo does.