The Expanse in Fate: Ship-Building

On with our adaptation of The Expanse to Fate! Along with character creation and ship combat, spaceship construction is one of the most important pieces in this system conversion. Compared to character creation, however, we don’t have as good an internal blueprint for how ships should be modeled in a role-playing game.

As I explained in my interlude, how detailed the ship rules should be in a specific campaign depends on how interested your group is in directly controlling ships and how often this element will show up in the story. At the most basic, ships may be a backdrop, important but more of a scenery aspect the way space stations or planet-side locations may be. At the other end of the spectrum, ship-to-ship combat may be a your characters’ bread and butter.

I gave my players a mini-survey to see where their interest lie: Political intrigue, Action and suspense, Character drama, Spaceship combat, Mystery and investigation; Horror, Espionage, or Other. The two options that go no votes were horror, which didn’t surpris me, and spaceship combat, which did. I had my answer: keep the spaceship combat rules light for my players, don’t burden them with detailed mechanics they’re not interested in using. (Good thing I asked first!)

Therefore, I will use the lightest version possible in my own campaign; in essence, I will treat the AGE System ship profiles as narrative descriptions. Does it say the ship has a med bay? OK, your PC gets a bonus for recovering from appropriate conditions such as Injured or Wounded. Does it have an advanced sensor package? You’ll see other ships coming a little earlier in the fiction.

However, I promised you a more detailed version and here it is. I largely based it on Tachyon Squadron and its supplement, the Spaceship Construction Toolkit, but I do follow The Expanse RPG as closely as I can, especially in the technology lingo.

Dude, where’s my spaceship?


This step is specific to Fate. Ships in Fate are built as Extras, and they will get their own character sheets.

Our ships will an aspect or two, of course. The High Concept might be as simple as UNN Cruiser, or more flavourful like “Salvaged” MCRN Frigate With a Crew of Fugitives. One way or another, this aspect should reflect the ship’s size.


The Expanse RPG classifies ships by size, and a ship’s size category determines approximate length, hull quality, and crew complement. We have a similar tool in Fate, scale, and it is used in Tachyon Squadron so we have a relatively easy match. The Tachyon Squadron scale chart has been modified to encompass more categories since the range is greater in The Expanse.

Size (AGE) = Scale (Fate)LengthCrew Minimum (Standard)ExampleDescription
Tiny = Terrible (-2)5 m1 (2)Breaching podSo small they can accommodate a pilot and basically nothing else, not even a modular equipment bay.
Small = Poor (-1)10 m1 (2)Shuttle or skiff; RazorbackTypically have a pilot and possibly a co-pilot, no modular equipment bay. Grants a +1 bonus to Dexterity (Piloting) rolls made to defend against attacks.
Medium = Mediocre (+0)25 m2 (4)Ship’s boat, drop ship, patrol destroyer; Knight, MCRN Kittur ChennammaTypically have a pilot and a co-pilot, and don’t come with any adjustments. Have one equipment bay.
Large = Average (+1)50 m4 (16)Frigate, small freighter; Rocinante, XinglongHave two equipment bays, impose a -1 penalty to Pilot. They have a 1-shift Cosmetic Damage box on each damage track.
Huge = Fair (+2)100 m16 (64)Destroyer, freighter, large private yacht; Scopuli, GuanshiyinHave three equipment bays, impose a -1 penalty to Dexterity (Piloting). They have a 1-shift Cosmetic Damage box on each damage track.
Gigantic – Good (+3)250 m64 (512)Cruiser, medium freighter; MCRN Scirocco, MCRN Hammurabi, UNN Nathan HaleHave four equipment bays, impose a -2 penalty to Pilot, and have an aspect of Big Ship or something similar that reflects their increased bulk.. Have a 2-shift Cosmetic Damage box on each damage track.
Colossal = Great (+4)500 m256 (2,048)Battleship, large freighter; MCRN DonnagerHave five equipment bays or more, impose a -3 penalty to Dexterity (Piloting), and have an aspect of Big Ship or something similar that reflects their increased bulk.. Have a 2-shift Cosmetic Damage box on each damage track.
Titanic = Superb (+5)1 km+1,024 (8,192)Colony generation-ship; NauvooOne-of-a-kind.

Note that the Canterbury is a problem child using the profiles supplied in The Expanse RPG: its length (750 m) place it in the Colossal size category, but its complement is described as a crew of about fifty people and it’s not very well equipped, which would suggest treating it as in the Huge size category. My point is, those are rough outlines, and every ship will have to be treated as a distinct statting challenge, especially civilian ships which are likely to vary far more than military ones.

Scale Effects

When two entities enter into a conflict with one another, the differences in their scale come into play. For every step that separates them, apply one or both of the following effects to the larger of the two:

  • +1 to the attack roll OR +1 to the defense roll
  • Deal +2 shifts of harm on a successful attack OR reduce incoming harm by 2

How to apply these effects depends on what makes sense in context. Of course, if the conflict is between two entities of roughly equivalent size or scale, then none of these effects applies. They only come into play when the scale is unequal.

Crew Competence

Again, The Expanse RPG uses a scale for crew competence which is easily matched to the Fate ladder:

Competence (AGE)Skill Bonus (Fate)
IncompetentPoor (-1)
PoorMediocre (+0)
AverageAverage (+1)
CapableFair (+2)
SkilledGood (+3)
EliteGreat (+4)

The four spacefaring skills are Dexterity (Piloting), Accuracy (Gunnery), Intelligence (Tactics) and Intelligence (Technology).


Each ship has a quality rating on the adjective ladder, from Poor (-1) to Great (+4). The higher the rating, the better the ship’s frame and performance capabilities. There’s no mitigating factor to this—that is, a Poor (-1) ship has no meta-mechanical advantage over a Good (+3) one. These rules are for making the ship that you want, not balancing the scales.

A ship’s quality dictates its baseline shield and Weapon ratings, modifiers to spacefaring skills (if any), the number of upgrades it gets right out of the gate, and in some cases its capacity to withstand damage. Each ship also has one aspect that should be a reflection of its quality. For example, the Knight might have Old But Serviceable reflecting its Poor (-1) quality, and the MCRN Tachi might have Modern High-Performance Corvette to reflect its Good (+3) quality.

Poor (-1)A Poor (-1) ship has 1 shield, Weapon:0, and a -1 to all spacefaring skills. It also has shortened system damage tracks—combine the first two conditions (not counting cosmetic damage boxes) for each system, but the condition still only reduces the hit by 2 shifts. (For example, for Propulsion System Damage, the first condition would be “Minimize 1 die on Intelligence (Tactics) actions and Dexterity (Piloting) actions,” and the second would minimize a second die for both of those actions in addition to giving the ship an aspect of Drives Ready to Give Out.) If you’re using simple damage instead, it has three 1-shift boxes.
Mediocre (+0)A Mediocre (+0) ship has 2 boxes of hull stress track, Weapon:0, a -1 to two spacefaring skills, and standard system damage tracks for that ship type or four 1-shift boxes, if you’re using simple damage.
Average (+1)An Average (+1) ship has 2 boxes of hull stress track, no modifiers to spacefaring skills, standard system damage tracks for that ship type, and two upgrades.
Fair (+2)A Fair (+2) ship is the same as an Average (+1) ship, but with three upgrades instead of two.
Good (+3)A Good (+3) ship is the same as a Average (+1) ship, but with four upgrades. This is an exceptionally well-built ship.
Great (+4)A Great (+4) ship is the same as an Average (+1) ship, but with five upgrades. This is a cutting-edge and/or tricked-out spacecraft that most pilots will never even see, let alone fly.


If your ship is of Average (+1) quality or better, you’re entitled to some upgrades:

  • Increase the Weapon rating by 1, to a maximum of Weapon:3. A ship’s scale must be at least 2 to mount a weapon of rating Weapon:3.
  • Increase the Armor rating by 1, to a maximum of Armor:2. Costs two upgrades. A ship’s scale must be at least 1 to mount armor of rating Armor:2.
  • +1 Hull stress, to a maximum of 5 boxes of hull stress track.
  • +1 to one spacefaring skill, but no more than +1 to any given skill.
  • Add one 2-point cosmetic damage box to the top of one system damage track, to a maximum of one box added per track. This box carries no aspects or skill penalties. If you’re building an NPC ship and using simple damage, this upgrade instead adds two 1-shift stress boxes.

Modular Equipment

ADVANCED SENSOR PACKAGE: Maximize two dice in detection actions at the start of the encounter. This module occupies one modular equipment bay.

CARGO MODULE: The larger the ship, the more a single cargo module can hold. A scale 0 ship can accommodate a few crates of trade goods or carefully packed missiles in a single cargo module, while a ship of scale 3 can hold a scale 0 ship in a module configured as a hangar bay. Don’t get too lost in the details with volume capacity—this is mostly a narrative conceit, but an extremely handy one under the right circumstances. Cargo modules can also double as workspaces or labs.

GOOD JUICE: The ship’s supply of acceleration tolerance drugs (the juice) is especially high-quality, providing better performance in high-acceleration maneuvers: maximize one die in defend actions to avoid weapon attacks in engagements. This module occupies one modular equipment bay.

PLASMA TORPEDOES: The ship must have a Torpedo Launcher module. The ship is equipped with plasma torpedoes, designed to burn through hulls and inflict focused damage. Plasma warhead attacks a single target within its maneuver slot or one lower. Consumable. Action Skill: Intelligence (Technology), maximize one die. Special: Weapon:4 on successful attack. Special: Armor is only half as effective against this weapon’s attacks. This weapon occupies one modular equipment bay.

POINT-DEFENSE CANNON (PDC): One selection of this module provides PDCs to cover the ship’s forward arc, roughly 180° from the amidships forward. Two modules set up a PDC network that covers all angles around the ship. Can attack all targets within its maneuver slot. Action Skill: Intelligence (Technology), maximize one die.

RAIL GUN: Axial weapon; large, powerful mass driver cannon that uses electroconductive rails and the Lorentz Effect to accelerate a dense metal slug at very high speeds, relying on mass and sheer speed to punch clean through ships rather than warheads like with torpedoes. Requires significant power to fire and must charge briefly before firing. Add 1 to your ship’s Weapon rating for attacks made with Accuracy (Gunnery). This module occupies two modular equipment bays.

RESCUE MODULE: This module is designed to provide life support for ejected pilots scooped up in space. A single rescue module can sustain a number of people equal to (ship’s scale+1).

STEALTH: ∂∂This system temporarily redirects most electromagnetic emissions from the ship, casting an illusory image several dozen meters to one side, which fools an attacker’s targeting computer. ∂∂ Once per game session, declare that a successful attack against you in fact missed—it hit your illusory decoy instead. ∂∂This module occupies one modular equipment bay.

TORPEDO LAUNCHER: The ship must be at least Mediocre scale (+0) to mount a single torpedo launcher. Each additional scale category adds capacity for one launcher. Multi-warhead, attacks up to four ships on the same slot of the maneuver chart, or one ship on a different slot. Consumable. Action Skill: Intelligence (Technology), maximize one die. Special: Weapon:2 on successful attack. This weapon occupies one modular equipment bay.

TURRET: A turret is a dorsal or ventral gun affixed to a powered cupola capable of 360-degree rotation, manned by a gunner, that can fire in any direction. A ship must be scale 1 or larger to mount a turret. To mount two turrets, a ship must be scale 2 or larger. In story terms, a turret is interesting (1) if a player character is going to to be posted there, or (2) as a high-value target on an enemy ship. If there’s no gunner available, a turret can be fixed in place and fired by the pilot, in which case it works like any other gun. If manned, the turret can only target ships within one maneuver slot of its position, but that ship can be higher, lower, or in the same slot. Turret guns start with Weapon:0, regardless of the Weapon rating of the ship’s rail gun or PDC. This can be improved with ship upgrades. If the gunner’s ship is on an enemy ship’s tail, either the pilot or the gunner can benefit from that positioning each turn, but not both. Turrets have their own system damage track and can be specifically targeted by enemies. If targeted, the pilot defends using Dexterity (Piloting) with a +1 bonus. Turret gunners don’t participate in the detection or maneuver phases of an engagement and have a limited range of actions they can take once the engagement begins.

Hull Rating and Stress Tracks

Spaceships hit by weapons fire and space hazards take hits (computed in the usual Fate method, equal to the difference between attack vs. defense rolls plus the attacker’s Weapon rating). Hits must be absorbed, which you can do in two ways: your hull can be weakened and you can accept damage.


A ship’s hull is given an armor strength rating, typically 0 through 3 but some are stronger. The rating of the hull armor is how many shifts of hits, in total, it can absorb before it disintegrates. So if you start with strength 3 hull, get hit by a 2-shift blast, then take 1 more shift in the next round, you have no more armor and hits will go directly to ship damage.

Freighters and other civilian ships rarely have armor, so they usually have a hull rating of Armor:0. Military ships typically have a hull rating of 1 to 3.

Ship Damage

If your armor rating is reached (in damage value) and you either have hits remaining from the attack or a new attack, your ship sustains damage. Each instance of damage mitigates up to two shifts. For each instance of damage, roll a single fate die and check off the next box in the appropriate column ([-], [0] or [+]). Penalties listed are cumulative. Some slots also hit you with an aspect that your opponents can invoke (and get one free invoke).

A standard ship damage track might look like:

Simple Damage

To make the GM’s life easier, some enemy ships have two ways to track damage: regular damage and simple damage. Regular damage is what we were just talking about. It’s recommended to use that system to track damage for elite or veteran enemies, recurring bad guys, important battles, and the like.

Simple damage simply tracks how many shifts of damage the ship has absorbed. It’s listed like this: ( [1][1][1] ) [1][1][1][1] That means that the ship can absorb a total of 7 shifts of damage. Mark off a box, starting on the left, for each shift of damage the ship suffers. When the last box is marked off, the ship is destroyed. The stress track set off by parentheses like this ( [1][1][1]) represents hull armor—when that’s gone, the ship’s ablative armor plating is gone.

Spaceship Engagements

By and large we’ll be using the engagement rules from Tachyon Squadron, but placing less emphasis on dogfighting and more on ship-to-ship engagements. I’m only providing the outline; for detailed descriptions and example, see Tachyon Squadron.

An engagement is a highly structured form of Fate conflict used to resolve space battles involving spaceships. The heart of it is in the maneuver and action phases, where every vessel in the combat works to gain advantage—an abstract concept representing optimal position, velocity, and several other factors—and may attack targets with advantage equal to or less than they have. Engagements make use of a Maneuver Chart:


The engagement consists of four phases.

1 Detection: Determine whether any ships are undetected going into combat.

2 Maneuver: Establish which pilots have advantage over others, enabling them to attack. If you want to concede or attempt to disengage, this is the time.

3 Action: Make attacks, create advantages, and perform all sorts of other actions.

4 End of Round: Degrade your maneuver chart position (slide your ship down one slot). Return to the maneuver phase. Repeat the cycle of maneuver-action-end until one side is destroyed or disengages.

Detection Phase

Every pilot and the GM make overcome actions with Intelligence (Technology). Look at where the GM’s result falls in the range of player results:

  • GM beats highest player: One GM ship (or flight) is undetected (w/ style = all GM’s ships)
  • GM between highest and lowest player (including ties): Nobody undetected
  • Lowest player beats GM: One PC-piloted ship is undetected (w/ style = all PC-piloted ships)

Some stunts and ship equipment change this—the text of the stunt or equipment gives you those details.

Maneuver Phase

In the engagement’s first maneuver phase, make an overcome action with the Intelligence (Tactics) skill for each spaceship. Place your ship marker on that value on the maneuver chart. Some stunts and actions change this—the text of the stunt or action gives you those details.

Action Phase

The pilot of the ship highest on the maneuver chart who hasn’t yet gone this round goes next. On your turn, take two actions from the list of available actions: Step 1 and Step 2. Play then passes to the next highest ship on the maneuver chart who hasn’t yet gone this round. Once all ships take a turn in the action phase, the phase is complete.

Pilots get two different actions—Step 1 and Step 2—in the action phase of engagements. A wide variety of actions are available.

Actions in The Action Phase (and the Steps They Can Be Taken On)

  • Desperate attack (full phase)
  • Large target strike (full phase)
  • On their tail (full phase)
  • Snap shot (Step 1)
  • Create an advantage (Step 1 or Step 2)
  • Overcome (Step 1 or Step 2)
  • Push (Step 2)
  • Repair (Step 1 or Step 2)
  • Rescue (full phase)
  • Shake off a tail (full phase)
  • Switch zones (Step 2)
  • Tactical refocus (Step 2)
  • Thin out the swarm (Step 1 or Step 2)

Turret gunners don’t participate in the detection or maneuver phases of an engagement and have a limited range of actions they can take once the engagement begins:

  • Large target strike (full phase)
  • Snap shot (Step 1)
  • Create an advantage or overcome (Step 1 or Step 2): Limited to Accuracy (Gunnery)
  • Repair (Step 2): Limited to clearing damage to the turret itself, unless the gunner uses a full-phase action to leave the turret and effect repairs elsewhere
  • Shake off a tail (full phase): Using Accuracy (Gunnery) instead of Dexterity (Piloting)
  • Thin out the swarm (Step 1 or Step 2)

End of Round

Every ship’s position on the maneuver chart degrades (moves down one slot) unless an action, stunt, etc. says they should not. Return to the maneuver phase.

In a next instalment, I will give you some ship profiles all statted up and my reasoning for the design choices.

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