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:
Star-Type

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)

Debris

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...

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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.