D&D Spaceship Combat

Not So Simple Spaceship Combat Rules for Dungeons and Dragons
(Based upon Blog of Holding's "Super-Simple Naval Combat for Any Edition")

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Ships can be composed of Modules
-Each Module has its own hitpoints, its own function, its own armor class, etc.
-Modules tend to be interdependant. A crew module does not make a spaceship, so if the crew module is all that is left, there may be a problem.
-Ships don't have to be modular.
-Ship parts are immune to psychic damage, obviously.

Ships have initiative.
-Ships have no initiative bonus. All crew, passengers, and modules act on the ship's initiative.

Modules can break when damaged
-Below half of its max HP:
--Engines reduce to 1/10 thrust
--Fuel tanks, Crew Modules, and other pressure vessels leak by 10% every round until repaired.
--Power generators reduce to 1/10 power.
--Crew within Crew Modules that are not wearing space suits are vulnerable to poison attacks.

Modules have Armor Class
-Tinfoil Ships, designed with a minimal structural budget and NOT for combat, have an armor class of 5. (eg, Apollo Moon Lander)
-Ships with a reasonable structural budget (eg Apollo Spacecraft) but not designed for combat have an armor class of 10.
-Ships designed for occasional combat, or for atmospheric re-entry, have an AC of 13. (eg Space Shuttle)
-True war ships have an AC of 16-18.

Ship Armor has Hitpoints.
-When Armor is depleted to zero, the Armor Class
-Default HP for Armor is equal to the Armor Class.
-If the armor represents non-ablative atmospheric re-entry shielding, it is immune to fire damage.

Ships fire Ranged Weapons.
-Each Round, a ship may fire any weapons that have crew.
-If the ship has two guns, but is a one-man ship, only one gun can be fired.
-Ranged Weapons have an unbounded range (on a combat scale) but finite speed.
--It is possible to retreat faster than the enemy's weapons can catch you.
-Weapons have a practical range beyond which they are inaccurate (1 extra roll of hit disadvantage per unit of range)
-Weapon Stats at the end of this document.

Ship Combat is at Province Scale.
-Province scale, according to 5e DMG, is a scale of 1 mile per grid unit.
-The reference frame is the position when the ship started combat.

Ships have a Speed.
-A speed of 1 is equivalent to a speed of 600 miles per hour.

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Optional Rules:

Ships have an acceleration and a Speed.
-A speed of 1 is equivalent to a speed of 600 miles per hour.
-An acceleration of 5 is equivalent to a change of speed of 600 miles per hour per six seconds, or 4.5 G, or a change of 1 mile/turn/turn. At 1G, this corresponds to either 0.2 miles per turn per turn, or 1 mile per turn per five turns.
-This mechanic is optional, as it gets very complicated very quickly, especially when accounting for delta-V losses.

Unguided Missiles can be Pre-Programmed.
-It takes 1d4 Turns to set up.
-The player operating the missile can add a guidance chip or guidance engine that will make it follow a predetermined non-straight-line trajectory.
-Success roll is required. (d20)

Crew Actions.
--Each player rolls for initiative. Within the turn of the player ship's initiative, they can perform a ship action.
--Captain: Choose an enemy to attack, add intelligence bonus to
--Pilot: Direct the acceleration and direction of the ship.
--Engineer: Repair any broken systems within a habitable section of the ship. (EVAs to perform repairs outside shouldn't be done in combat)
--Gunner: Direct weapons fire to specific parts of the enemy ship.

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Weapon Stats:

Low Tech (DnD Seige Equipment)

-Ballista
--AC: 15
--HP: 2
--A massive crossbow that fires heavy bolts. Hit 1d4 piercing.
--Speed: 0.5
--Range: 1

-Cannon
--AC: 19
--HP: 6
--A long tube filled with gunpowder which fires cast iron balls at destructive speeds. Hit 1d6 bludgeoning.
--Speed: 1
--Range: 2

Mid Tech (1800s-1920s)

-Artillery Gun
--AC: 18
--HP: 7
--A rather large gun. Hit 2d8 piercing.
--Speed: 3
--Range: 5

-Unguided Missile
--AC: 14
--HP: 5
--A rocket engine with an explosive on top. Spin stabilized to fly straight. Hit 2d10 fire. If roll = 2, then hit 1d4 bludgeoning.
--Speed: 6
--Range: 10

-Giant Gun
--AC: 19
--HP: 10
--A really very large gun. It can not be turreted unless mounted on a giant spaceship, so the ship must spend one turn pointing towards the target before it can fire. Hit 4d8.
--Speed: 5
--Range: 4

High Tech (Modern)

-Railgun
--AC: 18
--HP: 7
--A powerful electrically driven gun which drives particles to high velocity. Hit 2d8 for 2 rounds.
--Speed: 10
--Range: 200

-Flak Missile
--AC: 16
--HP: 5
--A guided missile which can track a moving target for 4 turns. Hit 2d10+2 fire.
--Speed: 13
--Range: Unbounded for 4 turns, then 10.

-Nuclear Missile
--AC: 16
--HP: 5
--A guided missile which can track a moving target for 4 turns, and then detonate a nuclear bomb. Hit 6d10 radiant for everything within 2x2 miles.
--Speed: 11
--Range: Unbounded for 3 turns, then 10.

-Laser
--AC: 15
--HP: 7
--A beam of light, coming in two kinds: Infrared (fire damage), Visible (radiant damage). Deals 1d8 damage per turn for 1d8 turns.
--Speed: 31047 (light speed)
--Range: 300

Futuristic Tech (Fantasy)

-Phaser
--AC: 16
--HP: 8
--An energy weapon. Deals 2d10 radiant damage + 1d8 necrotic damage.
--Speed: 31047 (light speed)
--Range: 300

-Disruptor
--AC: 21
--HP: 8
--An energy weapon. Deals 2d10 necrotic damage.
--Speed: 31047 (light speed)
--Range: 300

-Magic Ship-To-Ship Missile
--A burst of energy dealing 1d20 damage.
--Speed: 20
--Range: 300