This optional rules module covers planetary systems, movement of voidships within them (including to and from jump zones), and space battles. The rules are abstracted with little detail (borrowing from the original Mighty Empires seafaring rules), and you might consider to use a rules set such as the original Space Fleet (which would be my personal favourite) with its White Dwarf optionals, Battlefleet Gothic, or – still abstract but certainly more detailed – the second Rogue Trader (i.e., the Dark Heresy era Warhammer 40,000 Roleplay system) and its supplements in their stead to cover the space battles at least.
Ships
Unless also used as a base, ships typically do not have any detailed characteristics. Treat groups of small or otherwise weaker vessels (e.g., a squadron of escorts) as a single ship.
Especially powerful vessels may be assigned a simple modifier of +1 for space battles.
Particularly weak vessels may correspondingly be assigned a -1 modifier for space battles.
Especially fast or maneuverable vessels may be assigned a +1 modifier to Navigate (Stellar) tests for moving in-system and maneuvering in space battles.
Particularly slow or hard to maneuver vessel may correpondingly be assigned a -1 penalty to such Navigate (Stellar) tests.
Note if the ship is warp-capable.
Treat space stations as ships incapable of movement or maneuver.
It should be noted on a manifesto what cargo and passengers a ship carries, such as the retinue, armies, techarcana fragments, or supplies.
Fleets
Multiple ships that travel and fight together are considered a fleet (though squadron might often be a better term). A fleet’s speed and maneuverability are determined by its slowest and least maneuverable ship.
Systems
Note all points of interest within the system. Usually there are at least two: The jumpzone and a inhabited world. There may be more or less however. Others might include asteroid belts, gas giants, debris fields from ancient space battles, or deep-system space stations.
Record their distances from one another in a matrix. It is recommended to use Plasma Weeks as the unit of measurement, one Plasma Week being the distance covered by a typical ship with plasma drives in one week.
The greatest distance in a given system usually is the distance from the jumpzone (on the system’s edge) to the innermost point of interest. The distance from the jumpzone to inner planets, the most likely location of any inhabited world, is typically between 2 and 7 Plasma Weeks (1D6+1 when randomly creating systems).
The distance between some points of interest, e.g., a planet and a moon, may be 0.
Note if a point of interest is surrounding another, so that it is necessary to first move through/ past the one to reach the other (e.g., a dust cloud around a planet).
In-System Travel
As most points of interest tend to be in constant motion relative to one another, to go from one point of interest to another within system requires skillful plotting of courses and piloting to actually reach a destination and make optimal time.
Make one Navigate (Stellar) test per week. Success moves the ship or fleet one Plasma Week closer to its destination, i.e., it requires a number of successful tests equal to the distance noted in the system matrix to reach a destination point.
Encounters
Due to this, ships or fleets typically only encounter one another once they reach a common point of interest.
Deep space meetings or interceptions are very hard. They require the two (or more) ships or fleets to be the same distance from a given point of interest and then to each make an additional Navigate (Stellar) test – for a successful meeting, where all sides wish to make contact, everybody has to succeed at the test, whereas for a successful intercept, where only one side is trying to catch (up) with another whereas the other wants to avoid contact, the would-be interceptor has to succeed and the target has to fail the test for an encounter to occur.
Space Battles
Before a hostile encounter turns into a Space Battle, each side has one last chance to avoid combat by successfully testing Navigate (Stellar) with a penalty of 1 for every hostile fleet (or ship) encountered and an additional penalty of 1 if at least one hostile fleet is faster or more maneuverable.
If battle is joined, make two tests for each fleet – Command and Navigate (Stellar). Each success gives the fleet a +1 modifier, each failure a -1 penalty.
For each side add together the number of ships, potential battle modifiers of the individual ships, as well as the modifiers or penalties from the tests. Add an additional +1 for every ship that carries a substantial number of void- or ship-combat capable troops (e.g., a company or more of Space Marines) and the means to deploy them for boarding actions (e.g., Thunderhawk gunships, or a Teleportatorium). Finally, each side adds the score of a D6 to their total.
Consult the following chart.
Note that splitting up a fleet into multiple smaller fleets, e.g., to perform a pincer attack, can massively increase a side’s combat power – at the risk of actually reducing it, if tests are failed.
| Difference in score | Result |
| 0 | Draw – no losses sustained on either side |
| 1 | Inconclusive – 1 ship on each side lost |
| 2 | Hard-fought – 1D3+1 ships on the lower scoring lost versus 1D3 ships on the higher scoring side, the remaining ships of the lower scoring side are forced to retreat |
| 3 | Decisive – 1D6 ships on the lower scoring side lost versus 1D3-1 ships on the higher scoring side, the remaining ships of the lower scoring side are forced to retreat |
| 4+ | Overwhelming – all ships on the lower scoring side lost |
At the end of the battle roll a D6 for each ship that was lost. Apply +1 for ships whose side forced the enemy to retreat.
| D6 | Ship’s Fate |
| 1-2 | Destroyed – the ship is obliterated, any characters on board need to roll immediately on the casualty recovery table with a -1 penalty on the roll, survivors will be drifting in space in a spacesuit, lifeboat or trapped within a small section of the ship that was hurled away upon the vessel’s demise |
| 3 | Salvage – the ship is little more than a wreck, crew and passangers dead or dying, any characters on board need to roll immediately on the casualty recovery table, the ship itself is unable to move or fight, any facilities on-board are destroyed (leaving behind a fragment if a tech-arcanum), if it can be somehow brought into a spacedock, repairs will take 1D6 years |
| 4 | Crippled – the ship sustained critical damage but is able to limp away under its own power, if its side was forced to retreat and there are remaining undamaged enemy ships, it will be taken over as a prize, it is no longer warp-capable, and at -1 both to combat and speed (even if it used to have +1 in one or both), 1D6 facilities on-board are destroyed (leaving behind a fragment if a tech-arcanum) repairs will take 2D6 months in a spacedock |
| 5 | Damaged – the ship sustained heavy damage, roll a D6, on a 1-2 it is no longer warp-capable, on 3-4 it is at -1 to combat (even if previously at +1), and on a 5-6 it is a -1 to speed (even if previously at +1), in addition, one random facility on-board is destroyed (leaving behind a fragment if a tech-arcanum), repairs will take 1D6 months (1D6 weeks in a spacedock), the ship is able to rejoing any other surviving elements of its fleet |
| 6+ | Lucky escape – while put out of the fight during the battle, damage control parties and repair crews manage to revive the vessel quickly enough for it to make a successful break and escape, rejoining any other surviving elements of its fleet |
Planetary Defenses
A point of interest, most often a planet, might have defenses going beyond the capabilities of armed voidships – defence laser emplacements protected by planetary shields, anti-space missile silos sunk deep into mountain ranges, orbital minefields, and swarms of transatmospheric attackcraft are just a few examples. Defence lasers and shields are powered by giant plasma reactors or geothermal powerplants, providing them with practically unlimited endurance. Othe defenses, collectively called orbital munitions (be those attackcraft, missiles, or mines), are in more limited supply, with a planet having only a specified number of points of munitions stockpiled (although big arsenal and industrial worlds might be able to manufacture replacements and some rate).
Whenever a ship or fleet descends within the planetary defense envelope, as it must to perform orbital bombardment or to conduct landing operations, roll a D6 if the planet has defence lasers and roll an additional D6 if the defenders choose to expend one point of orbital munitions, on each roll of a 5, 1 descending ship is lost, and on each 6, D3 ships are lost.
Disabling planetary defenses may turn out to be just the mission for a well equipped retinue and warband spearheading a planetary assault.
Planetary Landings
Embarking or disembarking troops or cargo at a friendly spaceport is easily done. A lack of facilities, however, necessitates a roll on the below table. If the operation is aborted, a new attempt can be made after one week. If the landing is opposed by an enemy, planetary defenses may wreak additional havoc – for every point of orbital munitions the enemy expends, the roll is modified by +1.
| D6 | Ship’s Fate |
| 1-2 | Landing successfully carried out without losses |
| 3 | Landing aborted before any troops deployed |
| 4 | 1D3x10 % of landing troops lost upon approach, landing may be aborted at this stage, if not aborted an additional 1D3x10 % of troops are lost, the remainder successfully carrying out the landing |
| 5 | 1D6x10 % of landing troops lost upon approach, landing may be aborted at this stage, if not aborted an additional 1D6x10 % of troops are lost, the remainder successfully carrying out the landing, if the retinue was amongst the landing troops and all troops are lost, roll for Casualty Recovery |
| 6+ | All landing troops lost, if retinue was amongst landing troops, roll for Casualty Recovery with a -1 penalty |
New sample ship facility:
Planetary Assault Ship
When a ship with this facility conducts an opposed planetary landing, test Morale, if successful, reduce the effect on the landing of any planetary munitions employed by the defender by half.
Fleet Logistics
For long running, detailed campaigns, especially in reaches of space with little to no Imperial presence, tracking the supplies available to a ship might be of interest.
A ship’s stores are measured in years worth of supplies.
At the end of a year of operations without resupply, reduce stores by one. When stores reach 0 and each month thereafter until resupplied, roll on the table for combat losses above, applying a +4 modifier for the first roll and reducing the modifier by 1 on every subsequent roll (down to 0 but no further).