Traveller ATU: Early Colonization: Game Rules

Early Colonization: Game Rules

Changes and Modifications for this ATU


Space Travel

Early space exploration shouldn’t feel too trivial, smaller ships, lower jump ranges and an “edge” which hasn’t been explored yet. At the same time want it to be as compatible as possible with the old ships and the original “feel”.


Drive Table

Tech level based drive tables can limit ship size and jump range while maintaining compatibility i.e. the table is from an earlier time and tech level.

Limiting the jump ranges early on limits the already explored range.


TL09 A

100   1


TL10 A B C D

100    2 2 2 2

200    1 2 2 2

300    # 1 2 2

400    # # 1 2

600    # # # 1


TL11 A B C D # E F G H

100    2 3 3 3  #

200    1 2 3 3  #

300    # 1 2 3  # 3 3 3 3

400    # # 1 2  # 3 3 3 3

600    # # # 1  # 1 2 2 2

800    # # # #  # 1 1 1 2

1000  # # # #  # # 1 1 1

1200  # # # #  # # # # 1


Navigation (optional)

Handwavium – jump requires large gravitational forces at both ends to work and needs at least one system to be fully surveyed to generate a jump path meaning:

  • ships can’t jump to empty space or from empty space (random jumps go to nearest system along same direction)
  • after jumping to an unexplored system need to survey it before jumping to another unexplored system

This handwavium creates a bit of geography making systems J2 and above harder to colonize early on.

Compatible with standard rules and OTU by simply saying they figured out how to do it later.

Requires the campaign sub-sector to have a lot of J1 connections to the home system – if not then ignore.


Classic Malfunctions

These can be used to construct an early exploration limit which fits the classic feel.


There are two malfunctions in the standard rules: drive failure and misjump.

  • drive failure 13+ with DMs for unrefined fuel, missing engineers and missing annual maintenance
  • misjump 13+ with DMs for unrefined fuel, inside gravity well, some unexplained advantage of scout/naval ships
  • unrefined 100cr and refined fuel 500cr
  • refined only available at A and B star ports

A 1:36 chance of either a drive failure or misjump using unrefined fuel seems too much of a risk for any commercial venture imo which would limit them to A or B star ports and travel between A and B star ports almost always involves stops at lower level ports. Travel away from refined fuel is viable for naval/scout ships because they have special DMs for no extra cost.

If special engines made scouts able to use unrefined fuel and they don’t cost extra then at a cost differential of 400cr per dton of fuel per jump you’d think commercial ships would simply buy them too.

So aim is to re-arrange all this to something which contains the same elements while feeling more consistent.


Jump Warping Level (JWL)

Rationale – going in and out of jump space puts gravitational pressures on the ship that can warp it slightly and over time the warping can lead to catastrophic failure.

A JWL of 24 is considered the limit of safety which is 24 jumps (a year’s worth) with refined fuel. This creates an exploration limit of 12 jumps (12 jumps out and 12 jumps back).

The maintenance procedure involves a gravitational dry dock large enough to hold the ship which uses gravity fields to push the ship back to its original shape taking roughly between half a day to a day per JWL – average two weeks.

  • refined fuel: JWL +1 per jump
  • unrefined fuel: JWL + mass category per jump

so a 100 dton scout or 400 dton mother ship both add JWL+1 per jump if using refined fuel – using unrefined the cout still adds JWL+1 but hte 400 dton adds JWL+3 – so the scout ship’s exploration advantage is it’s size rather than special engines


Mass Category

The list of ship size categories on the side of the drive table

  • 100 dtons, MC = 1
  • 200 dtons, MC = 2
  • 400 dtons, MC = 3
  • 600 dtons, MC = 4
  • 800 dtons, MC = 5
  • etc


Drive Malfunction

Roll 2D6 if attempting a jump with either a missing engineer or a JWL over 24 – drive malfunction on a 13+

  • +1 per missing engineer
  • +1 per JWL over 24


A jump drive malfunction displays as gravitational distortion which warps the ship – if a malfunction occurs roll 2D6 for when it occurs

  • 2-5: on entry to jump space: 1-6 hits
  • 6-8: within jump space: 1-6 hits
  • 9-12: exiting jump space: 1-6 hits
  • if occurs on entry then take hits in jump space and on exit as well
  • if occurs within jump space then take hits on exit as well

ships may be destroyed depending on where the damage is


Random Jump

If the jump-drive, power plant or computer are wrecked on entry into jump space or during jump a random jump occurs.

(see book misjump).



The book version of misjump is the random jump described above which is caused by a drive malfunction.

In my jump-drive handwavium the fuel is used to create the jump bubble

roll 2D6 if trying to jump with unrefined fuel or within the gravity well (100D) of a world

  • unrefined fuel DM+1
  • within 10D DM+4 per mass category
  • within 100D DM+2 per mass category
  • 13+ bubble doesn’t form, jump fuel lost, no damage
  • 16+ gravitational warping – as drive malfunction except definitely occurring on entry

similar if trying to jump in too close to a world (e.g. blockade running)

roll 2D6

  • unrefined fuel DM+1
  • within 10D DM+4 per mass category
  • within 100D DM+2 per mass category
  • 13+ bubble doesn’t deform properly, D6 hits
  • 16+ bubble doesn’t deform properly, major gravitational warping, 2D6 hits


World Stats



I’m treating the atmosphere types as harder, more distinct categories based on the sequence of life stages of an earth-like planet.

  • Trace (1): planet cooled, continents and seas formed, microbial mats underwater, heavy radiation
  • Very Thin (2,3): continents dead, life in the seas, some oxygen and ozone, medium radiation
  • Thin (4,5): land life along coasts, life in the seas, more oxygen and ozone, light radiation
  • Standard (6,7): life, plenty of oxygen and ozone, protected from radiation
  • Dense (8,9): optionally treat as unbalanced gases, too hot or too cold, ice age or global warming


  • if atmos 2-5 and size 3- can be standard but only at low altitude
  • if atmos 8-9 and size 9+ can be standard but only at high altitude





I’m treating psionics as initially triggered by jump travel so it’s relatively recent – no institutes

Eventually enough people get it that psionics can be born as well – start of Zhodani faction as a faction within the culture (and maybe Solomani faction as a resction?)


Tech Levels


  • TL9: fusion, grav, M-drive
  • TL10: J-drive a,b,c,d
  • TL11: J-drive e,f,g,h

TL10 is the default in this ATU, maybe TL11


Weapons & Armor
  • TL6: rifle
  • TL7: auto-rifle, flak jacket
  • TL8: advanced rifle, cloth, mesh
  • TL9: laser weapons, combat armor
  • TL10: advanced combat armor, reflec
  • TL11:
  • TL12: plasma weapons, battle dress


  • flak jacket: partial ballistic cloth – heavy armor
  • cloth: full body ballistic cloth – bulky heavy armor
  • mesh: light version of cloth reinforced with internal mesh – light armor
  • combat armor: improved cloth – heavy armor
  • advanced combat armor: combat armor with improved laser resistance – heavy armor
  • reflec: mesh with improved laser resistance – light armor


  • standard civilian: flak or mesh, kinetic weapons
  • colonial service: mesh, kinetic weapons
  • navy: mesh, kinetic weapons
  • standard military: combat armor, kinetics
  • marines: advanced combat armor, lasers
  • scouts: mesh or reflec, kinetics or lasers


Ship Design
  • fuel refining: 10 dton blocks
  • medibay: small/standard/large 4/8/16 dtons
  • workshop: small/standard/large 4/8/16 dtons
  • laboratory: small/standard/large 4/8/16 dtons
  • survey module: small/standard/large medibay 4/8/16 dtons
  • #
  • turrets 1 dton fire control + 1 per weapon (capacitors, reloads etc)
  • single turret 2 dton, double 3 dton, triple 4dton
  • torpedo 4 dton
  • torpedo magazine 4 dton
  • #
  • life pods 1 dton
  • human low berth 1 dton
  • livestock low berth 0.5
  • #
  • naval crews are often double the minimum needed
  • computer dton is subsumed within the bridge


  • ships legally need life boats or life pods for all crew – some will have both, some have life boats and a few extra life pods
  • human low berths are combined low berth / life pod – generally for colonists
  • standard low berths are for livestock but can be used for humans at some risk
  • medibays have 1, 2 or 4 medical low berths

survey modules:

  • small -> basic astrogation survey – planetary objects
  • standard: full astrogation survey – as above plus space anomalies
  • large: orbital planetary survey

fuel refining:

  • variable sized blocks – minimum 8 dtons
  • each block is half holding fuel tank and half purification plant
  • can purify a full tank in 6 hours
  • 8 dton block can purify 4 dton per 6 hours
  • 80 dton block can purify 40 dtons per 6 hours


Ship Combat

Unlikely to happen but weapon types may be used in other ways

  • book missiles are now torpedos – large, c. cruise missile size
  • torpedo bay has three torpedos, torpedo magazine has 2 reloads
  • turret missiles are small flare/chaff type missiles to confuse enemy sensors
  • missiles and sand have 3 shots and a reload of 3
  • missile fired gives DM-2 to be hit that turn
  • beam energy weapons do 1-6 hits
  • sand is fired to counter energy weapons
  • sand disperses energy – reduces hits by 1-6
  • 4 x weapon points can be combined into a medium laser (power 4 at close range, 1 at medium range)
  • 16 x weapon points can be combined into a heavy laser (power 16 at close, 4 at medium, 1 at long range)



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