System generator

Shamelessly pirated from the Rogue Trader (RPG) sourcebook Stars of Inequity, the tables for randomly generating a Star System a pioneering Exploratory Fleet might discover.

System Properties

System Features; make D6-3 rolls (min 1)

D10	Feature	Effects
1	Bountiful	Lots of mineral wealth. Choose one to all of: Add one extra Asteroid Belt/Cluster Increase minerals available on asteroid belts/clusters by 1d10-5 rolls Increase minerals available on planets by 1 roll Each planet has a 40% chance to have extra 'Exotic Resources' available
2	Gravity Tides	Treacherous skies. Choose one: Add 1d5 Gravity Riptides Maintaining a stable orbit around the planets in this system requires a skilled pilot. Interplanetary travel in this system is made at double speed, but is risky.
3	Haven	Peaceful system of garden worlds. Choose one: Add one Planet to each of the three Solar Zones Add +1 to Atmosphere Presence rolls and +2 on Atmosphere Composition rolls for Planets in the Biosphere zone Add +2 to Habitability rolls for Planets in all zones
4	Ill-Omened	Cursed, either in fact or in legend. Crew morale will suffer just by arriving and will stay fragile until you leave.
5	Pirate Den	A wretched hive of scum and villainy. You must be cautious. D6+4 ships are present, including a beefy flagship, and 50% chance of a space station base.
6	Ruined Empire	A Xenos or Dark Age civilization once lived here. Choose one: D6-2 Planets gain a Xenos Ruins Resource. Increase Abundance of each by D10+5 (out of 100) D6-2 Planets gain an Archaeotech Resource. Increase Abundance of each by D10+5 (out of 100) In either case, this affects a minimum of 1 Planet and if there are more Resource deposits than planets the remainder are Derelict Stations or Starship Graveyards.
7	Starfarers	There are several planets and a civilization (human or xeno) which spans them. Minimum 4 Planets in the system; add more wherever if it falls short. The native civilization inhabits D6+3 Features, planets first. Any planet with a native civilization has this one, with Development level Voidfarers, Colony, or Orbital Hab, with at least one Voidfarers in the system.
8	Stellar Anomaly	Some star systems don't fall into the neat "planets orbit star, stars orbit galactic center" bucket. This is one; there's some fuckhueg negative space wedgie affecting the local gravity. Remove any 2 Planets generated in the system as they or their orbits are destabilized. Navigating within and through this system is easier since these wedgies are used as Navigator's landmarks. Local Warpspace is also calmer, but sudden reversion to realspace is more dangerous with a high chance of Gravity Riptide, Solar Flare (even if not near a star), or Radiation Burst.
9	Warp Stasis	A calm Warp isn't always good; sometimes it becomes "becalmed in the Warp". Double the base time for any trip entering or leaving this system and the time to send or receive an Astropathic message. It may also be harder to use psychic powers of any kind in the system.
10	Warp Turbulence	This isn't a true Warp Storm, but that may not be much consolation. All Warp jumps into or out of this System are more difficult. Some of the following may also be true: One planet in the System is the center of a very small Warp Storm, making it inaccessible and the rest of the system even more difficult to navigate. Psychic powers have stronger effects than usual here Psychic powers are easier than usual to manifest here Perils of the Warp and the corruptive influence of the Warp are stronger here

Star And Solar Zones

Roll for star strength and size, which then determines how much stuff is in each of the three Solar Zones; Inner Cauldron, Main Biosphere, and Outer Reaches

Star Properties; D10

Roll	Meaning
1	Mighty: Blazing, overpowering blue or blue-white light. Strong Inner Cauldron, weak Main Biosphere.
2-4	Vigorous: Steady white light. All zones normal.
5-7	Luminous: Well past its peak brightness, but steady yellow or yellow-orange. Weak Inner Cauldron.
8	Dull: This star will live for millennia more, but it is unmistakably dying. It is large but dim, usually red. Strong Outer Reaches.
9	Anomalous: Dis's fuckin weird. It may be bilious green, nearly-invisible purple, or just about anything else. Make any one zone strong or weak.
10	Binary: Two stars. Roll D10; 1-7: the stars match; reroll once. 8-10: they're different; roll once for each. Reroll 9s and 10s, but if the stars match a 10 can mean it's a three-star system. Star characteristics are set by the appropriate roll; zone strength is set by the lowest roll, subtracting 1 for each extra star, min 1.

Zone Crowdedness

Zone Strength	# of System Element rolls
Weak	1d6-3, min 1
Normal	1d6-1, min 1
Strong	1d6+1, min 3

System Elements

Zone Features; D100 each

Inner Cauldron		Main Biosphere		Outer Reaches
Roll	System Element	Roll	System Element	Roll	System Element
01-20	No Feature	01-20	No Feature	01-20	No Feature
21-29	Asteroid Cluster	21-30	Asteroid Belt	21-29	Asteroid Belt
30-41	Dust Cloud	31-41	Asteroid Cluster	30-40	Asteroid Cluster
42-45	Gas Giant	42-47	Derelict Station	41-46	Derelict Station
46-56	Gravity Riptide	48-58	Dust Cloud	47-55	Dust Cloud
57-76	Planet	59-64	Gravity Riptide	56-73	Gas Giant
77-88	Radiation Bursts	65-94	Planet	74-80	Gravity Riptide
89-100	Solar Flares	95-100	Starship Graveyard	81-93	Planet
				94-100	Starship Graveyard

Element Descriptions

Asteroid Belt: A thinly-spread ring of rocks which may have once been a rocky world. This poses a minor navigational hazard for all travel in its Solar Zone, and has D6-1 Mineral Resource deposits.

Asteroid Cluster: A denser, cohesive group of asteroids, usually the remains of a shattered planet or moon. It is confined to a small volume but is a serious navigational hazard within its extent. It also has D6-1 Mineral Deposits, either within the asteroids or in the remains of ships destroyed trying to navigate it. Pirates often use these as cover.

Derelict Station: An old, empty space station. If there is a space-capable civilization in the system, it was their creation. Otherwise, roll on the Station Origins table and give it D6-1 (min 0) Archaeotech or Xenos Ruins Resources.

Dust Cloud: The leftovers of an asteroid field or solar flare, these can be used as sensor cover but are basically irrelevant beyond that.

Gas Giant: Usually not a useful planet directly, but frequently home to rocky moons which could be much more promising. Use the Planet generation table below.

Gravity Riptide: A major navigation hazard and one that's very hard to detect from a distance.

Planet: A rocky world, potentially suitable for human habitation. Use the Planet generation table below.

Radiation Bursts: Not localized, but affecting the whole Inner Cauldron. Detecting an imminent burst is tricky but possible, and a skilled Enginseer's care for the augur arrays, or taking refuge behind a planet or moon, can protect the sensors; otherwise they will be damaged and difficult to even begin repair on for several hours. Even when there is no active burst, lower-level radiation makes all augurs and sensors noisy and unreliable in the area.

Solar Flares: Not localized, but affecting the whole Inner Cauldron. They are essentially unpredictable, and any journey through the Cauldron has a 10% chance per day of being hit by a solar flare, which is nearly as damaging as void combat weapons. Multiple instances of this each add 10% to the daily chance of being hit by a flare.

Spaceship Graveyard: A number of dead ships, floating in the void. Roll on the Graveyard Origins table to determine how they got here, and add D10+2 small Resource caches (Archaeotech or Xenos Ruins) spread across the dead fleet.

Ruin Origins

Derelict Station Origins; D100

Roll	Origin
01-10	Eldar Orrery: Wraithbone station with many cloistered cells, and psychic signatures of long-gone power
11-15	Eldar Gate: Wraithbone contraption in the shape of an enormous door. What could it possibly be?
16-30	Ork Rok: From a distance, this looks like an asteroid, but it's hollow and full of Ork 'technology',
31-45	STC Defense Station: A commonplace core pattern found across the Imperium, customized to defend a human colony.
46-65	STC Monitor Station: A commonplace core pattern found across the Imperium, customized with extensive augurs and communications tools.
66-75	Unknown Xenos Defense Station: A heavily armed station of unrecognizable origin, clearly not built for human occupants.
76-90	Unknown Xenos Monitor Station: A station of unrecognizable origin, with many sensor arrays and clearly not built for human occupants.
91-95	Necron Station: Station made of the Living Metal characteristic to the Necron xenos. Purpose unclear, probably defended by Canoptek robots.
96-100	Unusual Human Station: Structure and markings indicate this was built for humanity, but it is unlike usual patterns of station.

Spaceship Graveyard Origins; D100

Roll	Origin
01-15	Wrecked Battlefleet: Whichever side fielded these, they lost badly, and all hulks belong to the same force. 2D6 ships, most or all shattered beyond any value.
16-20	Fleet Engagement: Massive conflict raged here, with many hulks from both sides. 1d10+6 hulks, plus possible unexploded mines, torpedoes, or attack craft. A few might be worth salvaging.
21-35	Lost Explorers: Ships lost to overextended supply vaults, or failure of vital systems. D3 ships but most or all are salvageable.
36-65	Plundered Convoy: Plundered transports and cargo ships drift here, from an ancient shipping lane. D6+1 ships are here, all boardable but dsifficult to salvage and probably thoroughly picked-over.
66-90	Skirmish: Wrecks from a small battle, from two different sides, drift here. D6+2 hulks, all heavily damaged but possibly sturdy enough to salvage.
91-100	Unknown Provenance: Bizarre assortment of different vessels drifting past defies easy explanation. Dozens of utterly ruined ships, D6 hulks with some integrity remaining. No shared origin is plausible.

Planet Properties

Gross Properties

Gravity and Surface Composition

Planet Size and Mass; D10

Roll	Meaning: Rocky Planet
1	Small, Light: The already-small world is low in metals, and so has even lower mass than it appears.
2-3	Small: Too small for strong gravity or abundant resources. Subtract 5 from the result of its Gravity roll.
4	Small, Dense: As Small but with higher gravity and more mineral resources available.
5-7	Large: Worlds of this size can range across a vast spectrum of possible types.
8	Large, Dense: As Large but with higher gravity and more mineral resources available.
9-10	Vast: Huge and voluminous, worlds of this type strain the upper edges of the possible size for a single world. Such planets tend to be of middling density, as they are already more massive than is common. Add 5 to the result of its Gravity roll.
Roll	Meaning: Gas Giant
1-2	Gas Dwarf: Considerably more massive than most rocky planets, but small for its kind. Subtract 5 from the result of its Gravity roll.
3-8	Gas Giant: Vastly more massive than any rocky world, with accordingly powerful gravity.
9-10	Gas Titan: The titans among gas giants are larger than some small stars, and may even be 'Brown Dwarfs', arguably closer to being stars than planets. Roll another D10; on an 8+ this is a Brown Dwarf; its Gravity roll is an automatic 10 and its moons are generated as if they were one Solar Zone closer to their star. On a 1-7 it is an 'ordinary' titan and merely adds 3 to its Gravity roll.

Dense: A Dense planet adds 5 to the result of its Gravity roll. Increase the Abundance of any Mineral Resources it holds by 10.

Light: Subtract 2 from the result of its Gravity roll, and halve the Abundance of any Mineral Resources it holds.

Gravity; D10

Roll	Meaning: Rocky Planet	Orbital Feature Rolls
-6-2	Low Gravity: Subtract 10 from its rolls for Orbital Features and subtract 2 from its roll for Atmospheric Presence. Maneuvering on this world may be difficult for those not accustomed to it.	D2
3-8	Normal Gravity: Approximately the same gravity as Terra's standard 1 G. No effects.	2D3-1
9+	High Gravity: Add 10 to this planet's rolls for Orbital Features and add 1 to its roll for Atmospheric Presence.	D6+1
Roll	Meaning: Gas Giant
-4-2	Weak: Weak gravity for a gas giant, though still stronger than almost all rocky planets. Subtract 5 from its rolls for Orbital Features.	D6
3-6	Strong: Enormous gravity field, normal for its type. No effects.	D6+D3
7-9	Powerful: Objects well beyond its immediate surroundings feel its pull. Add 5 to its rolls for Orbital Features.	2D6
10+	Titanic: Even the system's star is affected by this world's gravity. Add 15 to this planet's rolls for Orbital Features.	3D6

Air and Orbit

Orbital Objects; D100

Roll (Rocky)	Roll (Gas)	Feature
-9-30	-4-15	No Feature: Nothing interesting added to the planet's orbit.
31-45		Large Asteroid: An asteroid large enough to be detectable by sensors, but not visible except as a fast-moving star to the naked eye, occupies a stable orbit around this planet.
46-60	16-40	Planetary Rings(Dust): A wide ring of fine particles circles the planet. This isn't a hazard to navigation, but does make sensor readings noisier. If this is rolled multiple times, enlarge the rings rather than adding more sets of rings. Sensor readings get progressively harder as the rings get larger.
61-90	41-70	Lesser Moon: Large enough to have a noticeable gravity well, but smaller than even a small rocky planet and often not massive enough to be a proper hydrostatic spheroid. Roll D10; on a 6+ it is rich enough in minerals to count as a Mineral Resource, generated normally but with Abundance reduced by 5.
	71-85	Planetary Rings(Debris): A narrow band of asteroids or chunks of ice extends out around the Gas Giant. The spread is limited enough that they can be avoided with a short detour, but if the detour is skipped, navigating them is like navigating an Asteroid Field system feature. If this is rolled multiple times, increase the size and density of the rings, making the needed detour longer and the navigation through them harder.
91-100+	86-100+	Moon: A true moon, massive enough to form a proper hydrostatic spheroid. Generate this as a new Rocky Planet, but its mass must be less than its primary. If the primary is a rocky world, the moon's Body must be less than the primary's Body. If the primary is a gas giant, the satellite's Body must be less than (the primary's Body+4).

For a gas giant, you're done here. For rocky planets, continue to generating its atmosphere and biosphere.

Atmosphere Density; D10

Roll	Meaning
-4-1	None: No atmosphere,or almost none. Operating on its surface requires the usual tools and protection for working in vacuum.
2-4	Thin: The atmosphere is very thin, making any dangers from toxic gases reduced but also making it very difficult to breathe.
5-9	Moderate: The density of the air is normal or nearly so, and imposes no extra strain.
10+	Heavy: Air so thick it is crushing. Any dangers from toxic gases are more severe, and breathing the dense, heavy air is stressful, preventing unaugmented humans from getting proper rest.

If no atmosphere, you're done here. If there is one, continue:

Atmosphere Composition; D10

Roll	Meaning
1	Deadly: You're basically swimming in an acid ocean. Even with total environmental seals, you're probably living on borrowed time. If the atmosphere is Heavy, you're definitely living on borrowed time.
2	Corrosive: Poisonous to breathe and deadly on contact. If you're a SPEHSS MARINE you can probably make it a minute or two without a total environmental seal, but without it you're probably living on borrowed time.
3-5	Toxic: Poisonous to breathe, but only mildly harmful to walk through. You'll need a rebreather but not a full isolation suit.
6-7	Tainted: Trace elements will be harmful to breathe with long-term exposure, though spending a week or so breathing it shouldn't have much effect. Not great for colonization but fine for short-term exploration.
8-10	Pure: Rejoice! The air is clean and breathable by even the frailest of constitutions.

If the atmosphere is Toxic or worse, you're done here. If it's at worst Tainted, continue to the biosphere.

Biosphere

Climate; D10

Roll (Zone)			Meaning
IC	PB	OR
1-6			Burning World: The most moderate climate on the planet at night is still hotter than a nuke in the Sahara
7-9	1-3		Hot World: Most of the planet is incredibly hot, but some sheltered patches are merely as hot as the Sahara.
10	4-7	1	Temperate World: Praise the God-Emperor, this world is mostly habitable.
	8-10	2-4	Cold World: Most of the planet is incredibly cold, but some sheltered patches are merely as cold as Siberia.
		5-10	Ice World: Blizzards in Antartica got nothing on this planet.

If the planet has no atmosphere, its climate is instead extreme, based on the Zone it inhabits. Inner Cauldron airless planets are Burning Worlds, Outer Reaches Ice Worlds. Airless worlds in the Primary Biosphere can be either, either decided at random (use 1d2) or based on which other Zone their orbit is nearer to. Roll on the Water and Life table next, using the column corresponding to the planet's type. If the world is Burning or Ice-bound and a result indicates it bears extremophile life forms, the world bears 'Trapped Water' as described in that result, and additionally you may choose to ignore the life rolled and treat it as a pure Trapped Water result. You may optionally roll even if the world has no atmosphere or a toxic atmosphere, in which case it may bear extremophile organisms which do not make use of water in their biology.

Life and Water; D10

World Type:Roll				Water and Life
Temp.	Hot Cold	Burning Ice	Toxic Airless
<0	<2	<5	<6	Hostile: Not only is there no water, it would be difficult or impossible to introduce any.
0-1	2-3	6	7-8	Inhospitable: There is no water or life to be found on this world.
2-3	4-5	7		Trapped Water: Whether vapor, ice, or mixed with severe contaminants, water exists here but is very hard to come by.
4-5	6-7			Lifeless Oceans: Liquid water is readily available, but no native life exists. (Yet?)
6-7	8-9			Minimal Ecosystem: Native life exists, but it is limited in form or distribution and without much variation.
		8-9	9-11	Minimal Extremophiles: Native life exists in the extreme conditions, in isolated pockets.
8-11	10+			Thriving Ecosystem: Native life is diverse, plentiful, and wide-ranging; most or all parts of the planet have native species.
		10+	12+	Thriving Extremophiles: Despite the harsh conditions, native life is plentiful and wide-ranging
12+				Abundant Ecosystem: Native life is so rich that it has numerous properties uniquely useful to the galaxy, if you can find them

Regardless of whether the world bears life or water, next roll for the distribution of its land.

Table Name; D10

World Type: Roll			Meaning
Hostile Inhospitable	Trapped Water Extremophiles	Lifeless Oceans Standard Ecosystem
1-9	1-7		Unbroken Surface: The planet's crust is uniform without substantial cracks or segments
		1-3	Supercontinent: All dry land is one contiguous cluster, with only a few small islands set apart
10	8-9	4-6	Few Continents: D3+1 landmasses make up the land surface, divided by oceans or something more exotic
	10	7-10	Many Continents: 2D3 landmasses make up the land surface, with many islands and archipelagos besides.

Environment and Riches

Territories

Base Terrains

Territory Number Modifiers

Planetary Details	Territories
Base rolls
Hostile	N/A
Inhospitable	0
Trapped Water	D2
Lifeless Oceans	D3
Extremophiles	D3
Standard Life	D6
Size-based modifiers
Body: Small	-3
Body: Large	-1
Body: Vast	+2
(n+1) Landmasses	+Dn
Ecosystem modifiers
Ecosystem: Minimal	+0
Ecosystem: Thriving	+2
Ecosystem: Abundant	+3

A world which is Hostile never has territories. One which is Inhospitable does not usually have territories, but may have them if modifiers add some.

Territory Type Modifiers

Planetary Details	Roll Modifier
Base roll	D6
Modifiers
Inhospitable	-2
Minimal/Thriving Extremophiles	-2
Trapped Water	-1
Lifeless Oceans	+0
Minimal/Thriving Ecosystem	+1
Abundant Ecosystem	+2

Base Terrain Type; D6 + modifiers

Roll	Base Terrain
less	Hybrid Terrain
0	Wasteland
1	Mountain
2	Wasteland
3	Mountain
4	Plains
5	Swamp
6	Waterways
7	Forest
more	Hybrid Terrain

Hybrid Terrain: Roll twice; the territory is a mix of the two types rolled. (Reroll results of Hybrid Terrain.) If  you roll two of the same terrain, the terrain is that single type, but has the Unusual Location trait and rolls for twice as many further traits as normal.

Wasteland: Frozen tundra, scorching sands, or many other things in between. Defined by being inimical to life, even native life. Wastelands are frequently found in regions of extreme heat or cold. You may add an additional copy of the Extreme Temperature trait after generating traits randomly.

Mountain Range: a chain of mountains, stretching across the landscape. Usually frost-capped peaks, but sometimes volcanic fissures. Useful for navigation.

Plains: grasslands, savannahs, stony plateaus, or other wide, flat expanses of land. Usually support some life, and sometimes a great deal of it.

Swamp: Abundance of water, not dangerous in itself but often hosting deadly disease and toxic creatures

Waterways: Whether large river, inland sea, or particularly interesting patch of ocean, this territory is all water.

Forest: an abundance of large-scale flora, and usually many other species, especially when tropical. Usually, but not always, trees.

Terrain Traits

For each territory, roll 2D3-1 to determine number of traits, then roll D100 on the table for the territory's base terrain type to select a trait. Reroll traits incompatible with previously-rolled traits. If the terrain is a hybrid, either divide the rolls evenly between its two base types, or make each roll normally but pick which table's result to use based on whatever criteria you wish. (Most traits can be applied more than once, intensifying the effect.)

Territory Traits

Wastelands		Mountains		Plains		Forests		Swamps		Waterways
1d100	Roll Territory Trait	1d100	Roll Territory Trait	1d100	Roll Territory Trait	1d100	Roll Territory Trait	1d100	Roll Territory Trait	1d100	Roll Territory Trait
01–20	Desolate	01–25	Boundary	01–10	Broken Ground	01–05	Exotic Nature	01–10	Expansive	01–05	Extreme Temp.(Hot)
21–40	Expansive	26–50	Expansive	11–30	Expansive	06–25	Expansive	11–30	Extreme Temperature	06–20	Expansive
41–70	Extreme Temperature	51–65	Extreme Temperature	31–45	Extreme Temperature	26–40	Extreme Temperature	31–45	Notable Species	21–40	Fertile
71–75	Notable Species	66–75	Foothills	46–70	Fertile	41–65	Notable Species	46–65	Stagnant	41–60	Notable Species
76–80	Ruined	76–85	Notable Species	71–85	Notable Species	66–80	Unique Compound	66–75	Unusual Location	61–70	Shoreline
81–95	Unusual Location	86–95	Unusual Location	86–95	Unusual Location	81–95	Unusual Location	76–95	Virulent	71–80	Stagnant
96–00	Roll again twice and apply both results	96–00	Roll again twice and apply both results	96–00	Roll again twice and apply both results	96–00	Roll again twice and apply both results	96–00	Roll again twice and apply both results	81–95	Unique Compound
										96–00	Roll again twice and apply both results

Territory Traits

TBD

• Landmarks: smaller, localized memorable things
• Resources: Valuable stuff, of different types and size of deposit, also used for non-Planet resources

Life

• Native Species, subsapient
• Inhabitants, sapient
  • Race
  • Tech Level