Here's a website where you can download my GURPS Handbook of the Planets
. This is an Excel workbook with no macros that implements the basic and advanced star system generation sequences from GURPS Space (4th edition)
, and is substantially faithful. (The few deviations from the algorithms given are documented on the website.) Only astronomical and planetological details are covered, though the Handbook
will generate population carrying capaicty if given a tech level, and GDP if the population and tech level are supplied by the user.
The star system and planet generation sequences from GURPS Space
4e are detailed and fairly realistic, and their output appears in real units etc. rather than anything game-specific. That means that this generator is as useful in other games as it is in GURPS
The GURPS star system generator has a really clever backwards-or-forwards that allows you either to generate the whole system from the top down, starting with the star and generating planets at random, or to start by specifying the planet you want and then generating a plausible astronomical context for it. Both sequences are implement in the Handbook of the Planets
. This system generator also allows you to generate stars at random, or to enter the characteristics of a desired star and work with those in either planet-generating mode.
This star system generator works from an explicit, user-supplied seed for its pseudorandom number generator. This allows systems to be recorded very compactly: the generator can be used as a catalogue, and the seed as a catalogue number. Supplied with the same seed, the generator will reproduce the same system.
I have provided a link to this before, in Board index » OTHER RPGs » General World and System Building
. But this is where people looking for such resources will more likely find it.