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Imperial Interstellar Scout Service Details of the worlds of the Imperium (and beyond).

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Old March 29th, 2006, 05:00 PM
Chaos Chaos is offline
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For me, the rules for star system generation as presented in the T20 THB (the only Traveller ruleset with world generation rules that I own) are, to put it bluntly, unsatisfactory. The rules for generating the star and any other worlds, planetoid belts and gas giants are more or less an afterthought to the creation of the mainworld; that is probably intentional, since the "action" in a star system is probably centered around the mainworld, but in a universe were space travel is so commonplace, I would expect the other bodies of a solar system to be settled, or at least exploited, to a significant degree.

For that reason, I have thought up alternative rules for generating star systems, taking a different approach.

(for ease of reference I am splitting this up into three posts; system generation, world generation, and colony generation)

Since IMHO the focus of interstellar colonization will be on systems which may contain habitable planets, my star generation rule generates only such stars:

Roll 1d6 for spectral class;
1 class F
2-3 class G
4-5 class K
6 class M
Then roll 1d10-1 for subclass (0-9); for class M stars, roll 1d6-1 only

The orbital radii given in the THB are for a G2 star; for less luminous stars, subtract 3% per subclass (i.e. -3% for G3, -6% for G4 etc., to -69% for M5); for more luminous stars, add 3% per subclass.

The innermost orbit occupied is determined by rolling 1d6/3, i.e.
1-2 orbit 0
3-5 orbit 1
6 orbit 2
The outermost orbit occupied is determined by rolling 2d6. Every orbit from the innermost to the outermost orbit is occupied by *something*.

For each such orbit, roll 1d6.
1-3 solid planet
4 planetoid belt
5 small gas giant
6 large gas giant
Sort the results, with the solid planets occupying the inner orbits, gas giants in the outer orbits, and asteroid belts in between.

The habitable zone in centered on a distance of 25 million kilometers plus 5 million km per spectral subclass above M5 (i.e. 30 million km for M4, 35 million km for M3 etc, giving us 140 million km for a G2 star such as Sol. The habitable zone extends 25% of that distance inward and outward, i.e. from 105 to 175 million km for a G2 star.
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