I’ve tried previously to create worlds in this setting with statistics compatible across multiple game systems – Traveller, Stars Without Number, Savage Worlds and 2300AD – and that rapidly became too much work for me. So, I’ll pick one and stick to it, namely Stars Without Number; because of all the games I know with world generation rules, that’s the one which gets you from dice rolls to playable adventures in the shortest time with the least effort.
The Dark Nebula map has 9 primary systems including the two capitals, 34 secondary and 9 tertiary. For purposes of fleshing them out, I’ll discard the tertiary systems, as they have no planets; that leaves me with 41 planets to work out.
The primary systems have naturally habitable worlds, which in Stars Without Number means they rolled 5-9 on 2d6 for atmosphere (breathable mix), 4-10 for temperature (cold, temperate or warm) and 6-8 for biosphere (miscible); the chance of getting all three right is about 25%, which is actually about right for the Nebula if we ignore the tertiary systems. (The optional rule to create a sector with mostly uninhabitable worlds, i.e. rerolling atmospheres or temperatures of 5-9, drops that chance to about 11%; neither option fits if we include tertiary systems, which gives us 17% habitable planets.)
Primary worlds must all have breathable atmospheres and miscible biospheres; that only leaves temperature as a variable, and statistically out of 9 of them I should expect there to be two cold, five temperate, and two warm; it seems sensible to me that the capital worlds (Kuzu and Maadin) and the campaign base world (Mizah) should be the most habitable, so they get temperate – you’ll see how the rest shape up in later posts.
On previous outings in the Nebula, I have tried numerous different ways of deriving the stats for secondary worlds from the map, but it never really worked; so this time they will be random, except that I will reroll as necessary to ensure that they are not naturally habitable, since the map has enough such worlds already .
My initial guess as to populations, now about 4-5 years old, still holds up statistically; out of 41 systems, we should have roughly two with billions of inhabitants (definitely Maadin and probably Kuzu), eight with millions (there are seven primary worlds if you don’t count capitals), and one alien civilisation (which might be Kuzu or Gazzain, depending which of my origin stories for the rakashans I decide to go with – but I don’t need to decide that just yet). That leaves the secondary worlds; there should be roughly one failed colony, two outposts, eight with tens of thousands of inhabitants, and 18 with hundreds of thousands. My usual approach here is to allocate populations based on the number of jump routes a system has; specifically, I look back to Classic Traveller and assign Capital worlds population level 9 (billions) to justify their status as Regional Hegemons, Tertiary worlds population zero, and Primary or Secondary worlds a population level of the number of charted jump routes plus one, with a +2 modifier for Primary systems. Thus, Hasara (a Secondary system with two routes) has population 3, and Mizah (a Primary system with five routes) has population level 8. I then convert that to SWN populations; levels 1-3 are either Outposts or Failed Colonies, 4 is tens of thousands, 5 is hundreds of thousands, 6-8 are millions, and 9 is billions. A bit statistically skewed, but it gives me a range and distribution of populations that I like. The implication of the SWN rules is that no population below 10,000 is self-sustaining, so each outpost is a base belonging to the nearest primary system.
Tech levels are easy to allocate at the top end, less so lower down; the two capitals get TL 5, a couple of the primary ones get 4+ and the rest 4 (because in the boardgame any of them might have starships); and I’ll dice for the rest, rerolling any results of 4+ or 5. I think anything down to TL 3 (20th century technology) should be able to perform frontier maintenance on a starship, but the starports on less-advanced planets have been set up for a reason, either by the local government or the nearest primary or capital world – that has implications for the political situation.
Planetary governments will each be a faction; the capitals are Regional Hegemons, outposts are Colony Worlds, and other primary and secondary planets have a Backwater Planet faction as their government. Most of these will never come into play, and are there just in case the PCs bump heads with them or ask awkward questions; every time one of Hegemons invades a planet, a Rebel Freedom Fighter faction will spring up there, and there will be a couple of other active interstellar factions, but more on those later as I develop their home worlds.
This leaves most of a world’s individuality coming from its tags; I have often considered dropping everything else and just using those, and I think that would work just fine.