Monday, November 28, 2011

Every Young Space Lord's Guide to Building Solar Systems

Here follows an incomplete rough-draft of a proposed system for generating Pulp-style Solar Systems for Space Fantasy/Sword & Raygun style RPGs like Humanspace Empires. It is still raw, and needs some play-testing/feedback. And editing. And serious expansion. The types of Stars and Planets available definitely needs to be expanded.

Pulp-Style Solar System Generation (Version .05)

Table One:
  1. O
  2. B
  3. A
  4. F
  5. G
  6. K
  7. M
  8. N (Neutron)
  9. E (Exotic)
  10. Special
(We'll need to define the star-types & include Exotic Stars like Black Holes, White Dwarfs, Green Stars, etc.)

Table Two:
Possible Companion Stars
  1. Solitary Star
  2. Binary System: Secondary
  3. Solitary Star
  4. Binary Star: Primary
  5. Trinary System: Secondary
  6. Exotic System
  7. Binary System: Secondary
  8. Trinary System: Primary
  9. Part of Cluster: roll 2d6 for close-stars
  10. Binary System: Primary
  11. Special
  12. Trinary System: Tertiary

Star Size-Category
Once you have determined the Type of Star, roll 1d10 to determine the Size-Category. Each Type will have a size of 0-9 (or 1-10 if you prefer). The number you roll for the Size-Category will be used as a modifer through-out the rest of the process.
  • Primaries gain +1d4 to Size Category. (Never go above 10, unless Exotic.)
  • Secondaries take -1d2 to Size Category. (Never go below 1, unless Exotic.)
  • Tertiaries take -1d4 from Size Category. (Never go below 1 unless Exotic.)
Available Planetary Orbits
Roll 1d4
  • Add 1d6 for Solitary Stars
  • Add 2d6 for Binary Stars
  • Add 3d6 for Trinary Stars
  • Add 4d4 for Clusters

Determine Zone-Type for each Orbit

  1. One Zone across system: (70%) Debris, (20%) Outer Planets, (5%) Inner Planets, (5%) Exotic.
  2. Two Zones: (50%) Debris, (20%) Inner Planets, (10%) Outer Planets, (10%) Habitable, (10%) Exotic.
  3. Two Zones: (70%) Debris, (5%) Inner Planets, (5%) Habitable, (10%) Outer Planets, (10%) Exotic.
  4. Three Zones: (60%) Debris, (10%) Inner Planets, (10%) Habitable Planets, (10%) Outer Planets, (10%) Exotic.
  5. Four Zones: (30%) Debris, (10%) Inner Planets, (20%) Habitable Planets, (30%) Outer Planets, (10%) Exotic.
  6. Five Zones: (70%) Debris, (5%) Inner Planet, (5%) Habitable, (10%) Outer Planet, (10%) Exotic.
  7. Five Zones: (20%) Debris, (20%) Inner Planets, (30%) Habitable Planets, (20%) Outer Planets, (10%) Exotic.
  8. Five Zones: (30%) Debris, (5%) Inner Planets, (45%) Habitable Planets, (15%) Outer Planets, (5%) Exotic.
  9. Special: More than Six Zones.
  10. Zero Zones: No planets present. (Possibly Artificial Habitats)

  1. Dust
  2. Small rocks, mostly grit
  3. Ice and dust, nothing very substantial
  4. Mostly pebbles with the occasional larger chunk
  5. Boulders mixed with fine particulate dust
  6. Huge masses like tumbling mountains, lots of impacts, very active
  7. Planetismals floating in mostly clear channels plowed through ice, dust and smaller bodies
  8. Remains of one or more former planetary bodies
  9. Mostly gas and dust, with some helpfully obscured fragments like cloaked icebergs
  10. Dense rings of dust
  11. Clumped-up pockets of rubble caught-up in the Trojan Points of nearby planets
  12. Exotic

Inner Planets
Inner planets have a base (5%) chance to have a moonlet and a (20%) chance of some sort of Outpost or Installation/Ruin.
  1. Hot, molten slag-world
  2. Burnt cinder
  3. Mesoplanet
  4. Totally unstable body ready to explode
  5. Oblong captured asteroid
  6. Rogue moon from outer planet
  7. Hyper-Hot-House World
  8. Exotic

Habitable Planets
Habitable planets range from size 0 Mesoplanet-sized asteroids to size 10 Super-Earths. They have a (30%) Chance to have 1d4 moons, per size category. Gravity and other environmental factors are modified on all Habitable Planets by the terraforming technologies of the Lords of Humanspace. There are no Uninhabitable Planets according to the Planetary Engineers of the Autocrator. No world will be allowed to defy the mandate of the Engineers nor the implacable will of the Autocrator.
  1. Water World
  2. Ice World
  3. Verdant World
  4. Desert World
  5. Airless Surface, Underground Ecology
  6. Hollow World
  7. Mesoplanet
  8. Overgrown: Jungle/Moldy/Fungal World
  9. Ruins
  10. Many islands, no continents
  11. One mega-continent (Pan-Gaea)
  12. One Face World
  13. Paired Contra-Worlds (Orbit exactly opposite one another)
  14. Wilderness
  15. Nature Preserve
  16. Restricted World
  17. Reservation World
  18. Enclave World
  19. Abandoned
  20. Exotic

Outer Planets
  1. Cold Gas Giant
  2. Ice Giant
  3. Hot Gas Giant
  4. Super-Massive rocky world
  5. Planetesimal
  6. Dwarf Planet
  7. Kuiper Belt
  8. Oort Cloud
  9. 2d4 Mesoplanets
  10. Exotic

Exotic Planets
  1. Remnant of Protoplanetary Disk
  2. Protoplanet (remnant)
  3. Debris Disk
  4. Strange Mesoplanet
  5. Antimatter asteroid
  6. Rogue Planet
  7. System is actually still emerging from a Nebula
  8. Entire system is still a Protoplanetary Disk, all planets indicated are inside the dust/debris of the Accretion Disk
  9. All planets indicated have been shattered in a cosmic cataclysm. Their orbits are now filled with debris. Have a nice day.
  10. Mega-Planet. All planets indicated have been compressed into one Mega-Planet...
  11. Mega-Structure. 1d6 orbits are taken up with a solar-system-scale structure.
  12. Even more exotic...
So that is a start...
We'll keep adding things to this until it becomes more workable or it collapses under its own weight and becomes a black hole, whichever comes first.


  1. Wow...that's looking pretty awesome. Happy to see green suns in there too,

  2. There goes more ink. Thanks my printer is going to kill me for printing out this awesome table, plus those articles,another copy of Human Space Empires,etc.

  3. @The Drune: Glad you like it--we're still sorting through notes for some additional things to add. Color-ranges for the various star-types. More sub-tables for Planetart rotation, orientation, extreme orbits, rogue moons, Hollow Moons, Giant Space Crystals, Quasars, etc.

    @ Needles: Once we ahve this nailed-down a bit more, we will offer it as a freebie PDF, if that makes you feel any better. It might also make it into one of the books for Humanspace Empires.

  4. I've made a post on the Menslagan system, generated using this method. One thing though - what are the percentage chances for Special orbits?

  5. @C'nor: We'll be very interested to see what you have come up with. It's a pretty bare-bones kind of system right now--needs a good bit more detail--like adding Special Orbits. We'll try to get something posted in the next day or so. Thanks for the help in testing this out!

  6. Awesome!

    It needs Cthonic Planets though!

    And carbon monoxide planets!

  7. @Blair: You bet. Planetoid-sized masses of crystals, and ammonia-based ecologies are on the way as well. We're going to add a sub-table for Background/native ecology that'll cover ammonia, sulfur, fluorine, methane and other forms of indigenous life--most of which will have been expunged or exterminated and replaced on Habitable Worlds, as was done with Tekumel...but those weird ecosystems will persist in parks, preserves, and so forth.

    Cthonic planets will be a sub-type of Underground ecologies.

    Atmosphere types will be another table.

    Just need to finish a few other things right now though.

    The Expanded system for Terminal Space goes in a whole other direction...but they will be complementary...hopefully.


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