Now we’re getting to the really interesting bits: Populating all those worlds. In the standard Traveller system, Population size is simply rolled with 2d6-2. The “hard science” rules add the following modifiers:
- If Size is 0–2 (low gravity world) then the DM is –1.
- If Size is A (high gravity world) then the DM is –1.
- If Atmosphere is not 5, 6 or 8 then the DM is –1.
- If Atmosphere is 5, 6 or 8 then the DM is +1.
With either variation, the end result is that almost all systems will be populated (2d6-4 means 83.33% of at least population 1). The digit translates like so:
A tiny farmstead or a single family
Tens of thousands
Hundreds of thousands
Tens of millions
Hundreds of millions
Present day Earth
Tens of billions
Hundreds of billions
Incredibly crowded world
The Slightly Modified Version
In essence, there’s nothing wrong with this roll – it fits the Traveller assumptions of a Earl Dumarest-style universe of countless inhabited but more or less isolated systems.
The assumptions aren’t quite what I’d like; I’d prefer highly-populated Garden worlds surrounded by tons of smaller border colonies.
With that in mind, I’d probably go with 2d6-4, and add (in addition to the “hard science” DMs):
- +1 if the world has water (hydropgraphics 1+)
- +1 if it is Temperate
- -1 if it is frozen or boiling
- -2 if it is searing
- -2 if size is 11 or higher
This way the maximum positive DM is +3 (2d6-1), resulting in “hundreds of billions” of people, and habitable worlds. A garden world will always be inhabited though; the GM should probably omit population rolls for worlds he knows were never explored or add a “fudge factor”, a negative DM for “undeveloped subsectors”.
A searing super-earth with an unpleasant atmosphere is 2d6-9, so it will have at most “thousands” of people.
An Asteroid base with temperate “climate” will be at the default 2d6-4, the same as in the standard Traveller rules (the additional -2 is negated by the +2 for temperate climate).
Again, these numbers would have to be playtested, but I think they should work.