Sci-Fi Planet Generator Running a tabletop RPG campaign in the vastness of space? Let me help you drum up a galaxy. by Alexander Vigna

Space... When creating a literal universe to play a role-playing-game in, one can find the work of creating the multitude of star systems and planets exhausting. This series of random tables is meant to speed up that process with every tabletop gamer's favorite tool: dice. Using a series of simple roll-tables you'll be able to come up with a virtually infinite number of unique solar systems for your players to venture through, even on the fly as they sail violently off your rails. I've only played 5th edition Dungeons & Dragons, but these pages are system-agnostic, so you'll find that they work for any tabletop RPG. Star Stuff First you must choose a number of solar systems for your players to have access to. You can't very well have planets without having stars now can you? Now, this part can be done manually, and frankly, should be. A nice simple number like 10 or 15 should hold your players over for a very long time. You can always add more as your players venture outside of the area. To give some scientific flavor to your fake corner of the cosmos, use a d8 and the table below to determine the sort of stars at center of these systems. For Binary Systems, roll two more dice, re-rolling 1s and 8s. Determining Star Type d8 Star Type 1 Binary System 2 Red Giant 3 White Dwarf 4 Red Dwarf 5 Medium Yellow 6 Medium Orange 7 Blue Giant 8 Supergiant Counting the Planets And now that you have the requisite amount of giant fusion balls and loose dust, let's make some planets. First the easy part: how many planets? Well again, this can be manual, but to relieve the pressure, I recommend a simple d10 roll, where you treat the "0" as an actual 0. Some stars might be quite lonely, but there can still be value in the asteroid fields, or adventure on a space station. Filling The Void I wish I could fill the void in my soul with a dice roll... Anywho, most star systems will have comets, or one or more systems of asteroids, even if they don't have planets. If a system has 3 or more planets roll a d4 twice, and add the features of the table below to the system to give it more character. For systems with 2 or less planets, only one extra feature should suffice. Star System Features d4 Feature 1 Asteroid Belt 2 Artificial Debris Field(s) 3 Frequent Comets 4 Space Station 23 Different Flavors Finally, the meat of this guide. The many, many, different kinds of planets. After you've figured out how many you have around a particular ball of hot gas, you must then determine what sort of environment is on those planets. Roll 2d12, and consult the table below. In the third column you'll find an example of the type of planet described from some popular sci-fi series, or a real one. Determining Planet Type 2d12 Planet Type Example 2 Mega City Coruscant (Star Wars) 3 Garden World Eden Prime (Mass Effect) 4 Overgrown Jungle Kashyyyk (Star Wars) 5 Ocean World Kamino (Star Wars) 6 Desert Tatooine, Jakku (Star Wars) 7 Frozen Wasteland Hoth (Star Wars) 8 Alien Jungle Pandora (Avatar) 9 Hot/Poison Atmosphere Venus 10 Radioactive Ruins Tuchanka (Mass Effect) 11 Lifeless Rock Mercury, Mars 12 Gas Giant Jupiter, Neptune 13 Lava Surface Mustafar (Star Wars) 14 Chemical Atmosphere Titan 15 Ice, Hiding Ocean Enceladus, Europa 16 Tidally Locked Rock Ryloth (Star Wars Legends) 17 Dangerous Swamp Dagobah (Star Wars) 18 Violent Storms Hagalaz (Mass Effect) 19 Crystal Planet Crait (Star Wars) 20 Savannah Dantooine (SW: KOTOR) 21 Ocean With Islands Ahch-To (Star Wars) 22 Abandoned Mega City Feros (Mass Effect) 23 Goldmine Planet 55 Cancri e 24 Profitable Gas Giant Bespin (Star Wars) 1

But What Do The Numbers Mean? What, 2-word descriptors ain't good enough for you? Fine, fine, here's a more detailed summary of each of type of planet. The majority of the finer points are still up to you as the one in charge of the universe, but I'll provide a short paragraph describing the basic conditions on each of the 23 kinds of planets. Mega City Coruscant, Ilium, Taris A planet that is entirely covered by a city will always have a population in the tens or hundreds of billions (at least). If this planet is in a space where travel is open and peaceful, then it is likely that the inhabitants of these worlds will be of various races. Planets like this need large, powerful governments, lest they fall into chaos. Markets on such worlds will have just about anything your adventurers need, but simple things like food must be imported and will be expensive. Mega cities make great capitals for large interplanetary empires. For added variety, consider rolling on the "crime level" table below. Mega City Crime Levels d4 Crime Level 1-2 Peaceful 3 Moderate 4 Chaotic Garden World Earth, Eden Prime, Naboo "Garden World" is a term used in science fiction to describe a hypothetical planet that has the conditions needed to create its own life. In real life, Earth is the only garden world we know of. When making a garden world for your game's setting, envision a young, idyllic, pre-humanity Earth. The sun shines brightly on a field of brightly-colored grass, and antelope-like aliens prance peacefully surrounded by butterflies. Ugh, gross. Odds are that such perfect places have been settled in some capacity by intelligent life, so consider rolling on the table below to see how much. In high amounts, they may begin to disturb the natural beauty. Garden World Settlers d6 Amount of Settlers 1 None 2 >1000 3 1000-10,000 4 10,000-100,000 5 100,000-1,000,000 6 1,000,000- 1,000,000,000 Overgrown Jungle The Forest Moon of Endor, Kashyyyk Similar to garden worlds, overgrown jungles are teeming with life. The primary difference is simply that they are more dangerous, and less beautiful. The climate may also not be a perfect Californian 70 °F, but a sweaty 90 °F. Some planets like this will have intelligent natives such as the Ewoks or Wookies of Star Wars. A simple coin flip should suffice to determine the presense of such creatures, if you must leave it up to chance. Ocean World Kamino, Mon Cala Scientists often like to say that if we look for a new home among the stars, we should look for water. Ocean Worlds are overkill, for us humans. We don't have gills, so we'd have a tough time settling down on a planet that is fully covered in liquid water. That said, Earth life began deep underwater, so it's highly likely that such a planet would be teeming with alien life. Modern sea life on Earth is also a common source of medicinal materials, so applying this same concept to your sci-fi setting can be a fun galaxy-building tidbit. For more randomness, I've created a small table of extra features below. Ocean World Extra Features d4 Feature 1 Floating Station(s) 2 Underwater Dome City 3 Huge Sea Monsters 4 Poisoned Water Desert Tatooine, Jakku, Arrakis I mean, you HAVE seen A New Hope, right? If not just stop reading this thing and go watch the single most-important science fiction film ever, please. That'll teach you everything you need to know about desert planets. A desert planet is either sparsely inhabited, like Tatooine or Jakku, or empty. That's about it. Oh, also, giant sand worms are a fun addition (read: Dune, 1965). If you happen to be playing the 5th edition of Dungeons & Dragons, then consider using the stats for the Purple Worm found in the Monster Manual for those. Below is a table with a few simple permutations of desert planets. Desert Planet Options d4 Features 1 Uninhabited 2 Small Settlement(s) 3 Uninhabited w/ Sand Worms 4 Settlements w/ Sand Worms 2

Frozen Wasteland Hoth, Noveria After you've watched A New Hope, I'm going to assume you watched The Empire Strikes Back, right? If not, please do yourself a huge favor. There's not too much to be said about frozen planets like Hoth, or Mass Effect's Noveria. There's two basic variables: Native life and outside settlers. I'd suggest just flipping a coin for each of those. No matter what both of those will be in small numbers. Alien Jungle Pandora, Felucia, Morrowind Now getting to the weird stuff: Alien jungles. There's really no need for a roll table on this one because such environments are by their very nature, weird. Any arrangement of giant mushrooms, killer plant tentacles, and colorful reptilian predators can make these planets both fun and dangerous to explore. If you happen to be playing Dungeons & Dragons, then consider using the creatures and descriptions of the Feywild for such worlds. Hot / Poison Atmosphere Venus Getting real for a moment, consider our neighbor Venus. About the same size, similar gravity, not too much closer to the sun... and covered in an atmosphere made almost entirely of acid, with an average surface temperature of 462 °C. Not a fun place, but great background for your planetary adventures. It could be an interesting challenge for your party to have to retrieve something from the surface of such a world. Radioactive Ruins Tuchanka, Earth in the Fallout series Imagine if the cold war had actually kicked off. Hundreds, if not thousands, of nuclear detonations in the space of hours. Needless to say, humanity would not have fared very well. In the Mass Effect series this happened to a hardy species called the Krogan, and it left their planet forever scarred. Plant life became unheard of for generations, and whole sections of the planet were rendered uninhabitable. Such worlds might actually be quite common. The only real variable to consider with these planets is whether or not anything still lives there, which you might decide with a coin flip. If your game prefers magic to science then consider re-flavoring the radiation as lingering dark magic. Lifeless Rock Mercury, Mars, Pluto, The Moon I shouldn't have to explain this one too much. Just a big 'ol rock orbiting a star with little-to-no atmosphere and no water. There might be valuable minerals or chemicals on such a planet however, so mining operations might be common, depending on the technology levels of your universe. For a fun plot twist, maybe have one of these planets have a ton of life living underground, sheltered from the elements. Gas Giant Jupiter, Saturn, Neptune, Uranus, Yavin Another simple one. These huge planets are quite common, cosmically speaking. How the players interact with these planets, if it all, is up to the technology level of your game, but odds are the crushing pressure and powerful gravity will make even getting near them a dangerous prospect. Flip a coin for pretty rings. Lava Surface Mustafar Now what good is a game without the token lava-based level? Not too much to say here. The whole surface of these planets will be either black stone or running lava. Generally the lava comes in slow, constant flows, rather than rare, powerful eruptions. The heat will generally be survivable in short bursts, but an atmosphere is likely to be smokey with sulfur. Or you could go the Star Wars route and have it be perfectly safe to breathe next to an active lava river. For Dungeons & Dragons, consult readings on the Elemental Plane of Fire for inspiration. Chemical Atmosphere Titan Consulting our own solar system again, we come to Titan, the largest moon of Saturn. The weird thing about Titan is that it is so cold that methane there behaves like water does for us. It exists in all three states of matter, and makes up lakes as well as clouds and rain. Such a planet is completely hostile to life as we know it, but imagining life that bases itself on a liquid other than water is a fun thought. Whatever RPG gaming system you use, remember that if you put life on one of these planets that you should use the most absurd and alien creatures your game offers. Ice, Hiding Ocean Enceladus, Europa And if you look to your left, you'll see two more objects from our solar system. Both Saturn's moon Enceladus and Jupiter's moon Europa are just big balls of ice at a glance, but popular theory states that they might contain a layer of liquid water deep below the icy surface, heated either by being bent by their gas giant's gravity, or radioactive minerals further down. Could such an ocean contain life? Well in your crazy sci-fi setting, why not? Most RPG systems offer plenty of aquatic creatures to discover in the depths. Maybe even a whole civilitazion down there. Flip a coin for intellegent life. Tidally Locked Rock Ryloth For a planet to experience "tidal lock" its orbital period must be exactly as long as its day. In other words, one side of the planet always faces its sun. This means that one half of the planet will be boiling hot, while the other will be completely frozen. Such a planet might have a thin ring (about 50-100 miles wide) of constant twilight that is actually quite pleasant, with plains or even jungles. You can roll on the following table to determine the condition of a locked planet's habitable zone. 3

Locked Planet Habitable Zone Type d4 Feature 1 Oceans and Lakes 2 Alien Jungle 3 Cities 4 Garden World Dangerous Swamp Dagobah A dark cousin of the Garden World archetype, the swamp planet is most famously seen in The Empire Strikes Back as the home of Yoda. There is generally little solid ground that isn't heavily saturated mud, and lakes and rivers are everywhere. Fog affects visibility frequently, and reptilian creatures make traveling there very dangerous. For Dungeons & Dragons, swamp planets make great homes for bullywugs, kuo-toa, and yuan-ti, among others. Violent Storms Hagalaz In Mass Effect 2, there was a planet with a day equal to 98 Earth days. This meant that one side would get very hot, and the other would be cold, much like a tidally locked planet. However, thanks to the slow rotation the hot and cold zones were constantly mixing at sunset/sunrise, meaning that instead of having a ring of pleasant, calm twilight, this planet had a ring of constant killer storms. Animal life is pretty much impossible on such a planet, but it may still have a breathable atmosphere and hardy plant species. Much like lifeless rock planets there may be valuable materials to be found here, and the storms make great hiding places for strong enough ships. Crystal Planet Crait Instead of a lifeless rock, imagine a lifeless crystal. A whole planet made mostly of quartz, malachite, or opal, instead of granite or sandstone. Such planets would be hostile to most conceivable forms of plant life, but The Last Jedi's Crait is home to some animals. A planet like this might be a good source of wealth for some creative miners, but typically the stones aren't especially valuable. Instead, such planets make great tourist spots thanks to the excellent views and stunning caves. Savannah Dantooine Another type of near-garden world, savannah planets are home to a great deal of life. Trees are sparse, and grasses dominate the landscape. The climate could be described as "a dry heat" year-round. On Earth, the African savannah is home to lions, elephants, rhinos and other desert-adjacent creatures. Such planets would actually be decent places to settle down, so I reccomend using the same population table as the one given for garden worlds, but re-roll 6s since these planets are a step down. Make sure water is present, but not abundant. Ocean With Islands Ach-To Imagine an ocean world that is 99% water instead of 100%, and this is the sort of planet you get. The islands here are usually the result of volcanic eruptions, or tectonic pressure that pushes up rock spires. The best example of this in recent sci-fi is Luke's planet from The Force Awakens and The Last Jedi, Ach-To. The island are typically of a tall, rocky makeup, with only simple plant life. Animal life on such planets would be interesting. Birds would do well by flying from island to island and hunting fish, but non-flying land life might be completely unique to each island, or at least each group (See: the Galapagos Islands). Settlements from off-worlders would be unlikely, just because of the lack of space. Abandoned Mega City Feros Here's an interesting question for you: what happens when a planet like Coruscant is abandoned? The answer: a huge amount of money and resources is left behind. But, in order for such a large population to be killed or forced out, some great catastrophe must have occured. Roll on the table below to determine exactly what brand of apocalypse ended life on your planet. What happened will determine the state your players find it in, and how dangerous it is for them to loot it. Cause of Abandonment d6 Apocalypse Type 1 Zombie Plague 2 War 3 War (interplanetary) 4 Sun Got Hotter 5 Sun Got Colder 6 Meteor Impact Goldmine Planet 55 Cancri e Goldmine planets are typically not too different from lifeless rocks. The key difference is that they are made almost entirely out of some sort of valuable material. Consider the implications of such materials on your universe's economy, and consider choosing this material yourself. If you still want to leave it up to chance, I have presented a few options below. Valuable Materials d4 Material 1 Diamond 2 Gold 3 Special Metal (ex: mithril) 4 Fuel 4

Profitable Gas Giant Bespin The last, and least common type of planet will appear to be a standard gas giant at a glance, but is actually more like a goldmine planet. Every space-based setting needs a fuel source, and a common one in science fiction is helium-3, a gas. Perhaps the fuel in your universe has a more exotic sounding name, but nonetheless a gas giant with a thick layer of it will be highly sought after. The only variable to consider is whether the gas is mined by small ships, or large installations like The Empire Strikes Back's Cloud City. Flip a coin if you'd like to leave it to chance. Moons, Moons, Moons! We've got stars, we've got planets, let's get even smaller now. Every good science fiction universe has moons almost as well fleshed out as its planets. Moons follow different rules depending on whether they're orbiting a rocky planet or a huge gas giant. Rocky Planet Moons First of all, we have to figure out how many moons orbit each of your planets. For small planets I recommend 1d4 - 1 moons. This leaves the possibility of having no moons, which both saves you work as the DM, and is scientifically plausible. The second thing to consider is what planet type each moon's environment is most like. Consult the table below, and remember that moons of this size have about 10-20% of Earth's gravity. Also remeber that goldmine moons are smaller than planets, and therefore contain less total value. Small Planet Moon Type d8 Moon Type 1-4 Lifeless Rock 5 Lava Surface 6 Ice, Hiding Ocean 7 Crystal Planet 8 Goldmine Planet Gas Giant Moons Gas giants have more moons on average, and with more variation. A good realistic number is 2d10, but to keep things reasonable as DM, perhaps just do 2d6 or 2d4. Another note to remember is that these moons are the same size as normal planets, and will act just like planets in every way. Gas Giant Moon Type d20 Moon Type 1-4 Lifeless Rock 5 Lava Surface 6 Ice, Hiding Ocean 7 Crystal Planet Gas Giant Moon Type (cont.) d20 Moon Type 8 Goldmine Planet 9 Overgrown Jungle 10 Alien Jungle 11 Frozen Wasteland 12 Desert 13 Ocean World 14 Hot/Poison Atmosphere 15 Radioactive Ruins 16 Chemical Atmosphere 17 Dangerous Swamp 18 Violent Storms 19 Ocean With Islands 20 Mega City Enter Your Name And now for everyone's favorite part of RPGs: naming things! If we're being frank I think that this works way better when you just make them up yourself. That said, I totally get that writer's block happens, so I've created a system of tables to help you name stars, planets, and moons. You could choose to just name each star system, and refer to the planets with names like Tarmoz I, Tarmoz II and Tarmoz III, or you could roll up names for each planet individually. Personally I prefer the second system in most cases, but the first is good for star systems that are newly discovered or sparsely inhabited. Moons could be individually named, or just referred to with names like “the third moon of Simik V”, if they're not particualarly interesting. The tables below present two sets of 100 single-syllable sounds. First, roll a d4 or d6 to determine how many syllables your planet or star's name has, then roll d100s for each, stringing together your results. You can go back and forth between the tables randomly for even more variety. If you happen to roll up a planet with a name too similar to something that exists in established sci-fi, consider using syllables from the other table to get rid of the ripoff names. Let's run a quick example. Say you rolled a 3 for the number of syllables. Roll 3 d100s. If you rolled a 24, 65, and 39, your planet or would be named "Gorrenla", once you get rid of the capital letters. If you use the second table instead, then this planet would be named "Gerrukleph". You could also then mix and match the two tables, getting something like "Gorrukla" or "Gerrenleph". You could even reverse the order of the syllables for a completely different name like "Larengor". Either way, there's no way you'll ever have to struggle to name a celestial body ever again. 5

Syllables Table I d100 Syllable 000 Aa 01 Ac 02 Ach 03 Ad 04 Ae 05 Ag 06 Ar 07 Arn 08 Ap 09 At 10 Az 11 Ba 12 Bo 13 Bun 14 Cer 15 Cot 16 Cyt 17 Do 18 Dut 19 El 20 Er 21 Eum 22 Fo 23 Gha 24 Gor 25 Hon 26 Him 27 Ik 28 In 29 Ip 30 Ir 31 Iz 32 Jak 33 Jot 34 Jun 35 Kah 36 Ker 37 Kun 38 Kul 39 La 40 Le Syllables Table I (cont.) d100 Syllable 41 Lor 42 Maa 43 Mar 44 Min 45 Moth 46 Mok 47 Must 48 Na 49 Nok 50 Niif 51 Nus 52 Oo 53 Ok 54 Or 55 Oz 56 Par 57 Pat 58 Pol 59 Puz 60 Qun 61 Quo 62 Qur 63 Raa 64 Rann 65 Ren 66 Ryg 67 Sal 68 Sim 69 Sin 70 Sol 71 Sor 72 Sur 73 Sym 74 Tat 75 Tol 76 Tu 77 Tun 78 Tyr 79 Ub 80 Uk 81 Un 6

Syllables Table I (cont.) d100 Syllable 82 Ur 83 Vaa 84 Val 85 Vex 86 Ver 87 Vu 88 Wa 89 Wan 90 Wii 91 Wik 92 Wun 93 Xo 94 Xur 95 Yar 96 Yul 97 Za 98 Zil 99 Zun Syllables Table II d100 Syllable 000 Ab 01 Aff 02 Ak 03 Al 04 Ao 05 Arg 06 Ash 07 Ath 08 Att 09 Ay 10 Bann 11 Bit 12 Borr 13 Bu 14 Cir 15 Cop 16 Cu 17 Da 18 Dit 19 Eeth Syllables Table II (cont.) d100 Syllable 20 Eph 21 Ez 22 Fa 23 Fin 24 Ger 25 Gi 26 Gol 27 Haa 28 Heg 29 Ip 30 Ium 31 Ix 32 Jaal 33 Jok 34 Jut 35 Kap 36 Kel 37 Laath 38 Lar 39 Leph 40 Ler 41 Luo 42 Mas 43 Mak 44 Mith 45 Mor 46 Moz 47 Nar 48 Nak 49 No 50 Nul 51 Nuk 52 Oa 53 Ob 54 Og 55 Ov 56 Paal 57 Pak 58 Pod 59 Put 7