Traveller ATU: Early Colonization: World Generation

Early Colonization: World Generation (wip)

generating a sub-sector that fits the early colonization theme


Campaign Sector

My baseline is  the standard rule that ship needs major maintenance annually and if it goes beyond that limit it starts to take increasingly difficult drive failure rolls every month (or every jump) and at the start of colonization (and for some time after) only the home world has the facilities to do this. This gives an exploration limit of 6 months out and 6 months back (or 12 jumps) or 12-72 hexes depending on drives and as a lot of the early ships involved will have J1 and J2 drives the limit is more like 12-24 hexes.

There will be various ways round this in individual cases but let’s say 24 hexes is a reasonable approximation for the extent of colonizable space available for early colonization before bases / colonies capable of large ship overhauls are built.


A close approximation to this amount of space would be a 6×6 grid of subsectors with the home world in the center – actually in one of the corner hexes of one of the four sub-sectors that makes up the core – which creates three rings of sub-sectors around the home world: the central core and an inner and outer ring of sub-sectors around the core.

outer outer outer outer outer outer

outer inner inner inner inner outer

outer inner corre corre inner outer

outer inner corre corre inner outer

outer inner inner inner inner outer

outer outer outer outer outer outer


Pick one subsector for the campaign start, this could be one of the core subsectors or one of the inner or outer subsectors depending on preference – note direction to home world.


Subsector Generation

  • blank subsector
  • if the chosen subsector is th eone with the home world then add home world system in the inner corner of the sub-sector
  • use standard UWP for the home world with class A star port, prime physical stats e.g. 767, TL10 or TL11, pop 9 and whatever govt type and law level you want
  • roll for presence of star systems in other hexes as usual
  • initially mark all systems as X
  • roll physical stats for each system

colony UWP form: name-system code – physical stats – native sentient code – colony code

name is initially just the hex number

system code is first letter of colony code

e.g. 1415-B-666-0-B2


System Code
  • A home world
  • B settlement colony
  • C refueling colony
  • D secondary colony
  • E refueling outpost
  • X nothing


Subsector Population DM

applies to all rolls for settlement colonies and colony population in the subsector

  • core subsector DM+1
  • outer subsector DM-1
  • early DM-1


  • early: core DM+0, inner DM-1, outer DM-2
  • late: core DM+1, inner DM+0, outer DM-1


Native Sentient Species

roll 2D6 for native sentient species

  • atmosphere 6-9: 2-5 none, 6-9 sentient, 10-11 hunter gatherers, 12 special
  • atmosphere 4-5: 2-7 none, 8-10 sentient, 11-12 hunter gatherers
  • atmosphere 2-3: 2-9 none, 10-12 sentient
  • size 0-3 DM-2
  • hydro 0 DM-2
  • hydro A DM-2
  • else 12+ sentient

sentient species on world with atmosphere 0-3 or A-C are either underwater (if possible) or weird science natives

  • sentient: ape-like
  • special: could be basic farming or herding or something exotic


Native Sentient Reaction
  • 2-5 hostile
  • 6-8 neutral
  • 9-12 friendly


UWP Code
  • none 0
  • hostile sentient 1
  • neutral sentient 2
  • friendly sentient 3
  • hostile hunter gatherers 4
  • neutral hunter gatherers 5
  • friendly hunter gatherers 6
  • hostile special 7
  • neutral special 8
  • friendly special 9
  • hostile weird A
  • neutral weird B
  • friendly weird C


  • hostile: 1, 4, 7, A
  • friendly: 3, 6, 9, C
Settlement Colony (B)

select prime systems (where size 4+ / atmosphere 6-9 / hydro 4-8)

roll for settlement colonies 8+

  • atmos 6: DM+4
  • atmos 7: DM+2
  • atmos 8: DM+2
  • atmos 9: DM+1
  • hostile natives: DM-2
  • friendly natives: DM+2


  • D6-1 population
  • 0: marked for colony
  • 1: advance team
  • 2: colonial service base
  • 3: first colonists
  • 4: stable colony
  • 5: self-governing


UWP Code
  • settlement colony B + population code
  • rejected prime colony site BF

rejected colony sites are still classified as B as BF colonies have special rules



  • settlement colonies that form a chain you may want to re-arrange population numbers so population decreases as you move further from out


Refueling Colony (C)

Once the settlement colonies are identified select the systems that make up the most logical route between the colony system and the home world that would be needed for refueling stops.



roll D6 for population code

  • 1-3: 1
  • 4-5: 2 (small alternate colony also)
  • 6: 3 (large alternate colony also)


UWP code
  • C + pop code


Secondary Colony (D)

other types of colonies mostly not intended to develop into a self-sufficient world

for example

  • research colony
  • resource extraction colony
  • terraforming colony
  • military base
  • penal colony
  • reclusive colony

select the systems that aren’t already marked as A, B or C

roll 8+ on 2D6

  • n = number of hexes away from A, B or C system -1
  • (adjacent hexes DM-0, 2 hexes away = DM-1, 3 hexes away DM-2 etc)
  • DM+2 native sentient
  • DM+2 adjacent to home world
  • DM+1 exotic atmosphere



roll D6 for population code

  • 1-4: 1
  • 5: 2
  • 6 3


UWP Code
  • D + pop code


Refueling Outposts (E)

In the same way that colonization service refueling colonies are used to link the settlement colonies; the scout service is used to provide refueling services to alternate colonies – at least the official ones.

Make a chain of refueling outposts to D colonies.



roll D6

  • 1-3: 0
  • 4-6: 1

pop 0 outposts are are automated


UWP code
  • E + pop code


Amber/Red Zones (wip)

option 1: Space Survey Level:

  • base astrogation data – needed for jump, short survey – pathfinders
  • full astrogation data –  needed for safe in-system travel, longer survey, main astrogation anomalies marked
  • complete survey: all astrogation related anomalies investigated and/or marked – rangers

so red could represent the first level and amber the second maybe

option 2:

  • red: systems with a hostile native lifeform, BF systems with hostile sentients are likely to be active combat zones
  • amber: any system with an exotic atmosphere or any BF system without hostile sentients – rejected prime settlement site implies some kind of unusually hostile environment

Red zones don’t imply travel to the system is restricted although if there are active military operations underway specific planets or regions might be restricted.


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