CV: Planetary Systems

Planetary Characteristics:

Atmosphere (-10 to +10 range)
Gravity (-10 to +10 range)
Radiation Level (-10 to +10 range)
Water Level (-10 to +10 range)
Temperature Range (-10 to +10 range)
Minerals (-10 to +10 range)
Size (in kilometers or miles diameter or something)
Type (gas giant, rocky world, icy world)
Day (in GSDs or GSHs)
Year (in GSYs or GSDs)
Moons (number, sizes, orbital periods)
Axial Tilt (degrees; determines #, severity of seasons)

(Dale's Version:)
Text in italics indicates optional rules that add detail to the game. These rules can be totally ignored to maintain simplicity and fast pace, or included for flavor, but GMs and Players should discuss the use of optional rules before play.

Atmosphere (-10 to +10 range) This stat represents both the breathability of the gasses in a planet's atmosphere, and the air pressure relative to human tolerances. A rating of 0 indicates a perfectly breathable, Earth-like atmosphere. An atmosphere 1 point removed from this ideal is uncomfortable to breathe, either due to abnormally high or low pressure, or noxious fumes. Humans can generally function normally in an atmosphere as low as -2 or as high as +2, but find it uncomfortable. Optional Rule: Colonists living in a -1 or +1 Atmosphere environment suffer a penalty to morale, and colonists breathing an unfiltered -2 or +2 atmosphere may even suffer detrimental health effects from long-term exposure, up to and including shortened life expectancy. (Examples from Earth include the air at extremely high or low altitudes, heavily polluted air, etc.) An atmosphere 3 points or more away from zero indicates an unbreathable atmosphere. Terraforming equipment can be used to gradually alter the planet's atmosphere, but shifting it further than 1 point in either direction will wreak major ecological havoc to any indigenous species. An alternative to terraforming is the construction of domes or other self-contained airtight structures to host an artificial earth habitat.

Gravity (-10 to +10 range) This stat represents the force of the planet's gravity. This is based directly on the planet's mass, which in turn is usually based on the planet's size. A gravity of 0 represents exactly one Earth G force. -10 is near-weightlessness, and +10 is strong enough to crush a human to a pulp. Generally, humans can function well enough in a gravity with a rating of -1 to +1, and the only long-term side effects might be that successive generations get slightly taller and thinner or shorter and stockier, at GM's discretion of course. High Gravity: A gravity greater than +2 imposes a penalty on movement equal to the gravity rating, and at ratings +5 and above, gravity damages any units not specially reinforced to withstand their own increased weight at a rate, of the gravity's rating in HP per combat round. If a unit's bulwark meets or exceeds the planet's gravity, or it is specially designed to stand up to high gravity, it will not take this damage,! although its passengers still will unless the player has invested in some sort of antigravity tech. Optional Combat Rule: If combat is taking place in a high gravity environment, ranges for all ballistic and missile weapons are reduced by the planet's Gravity Rating x 10%. (I.E. a pistol fired on a planet with a gravity of +5 only has half its normal range; a pistol fired on a +10 world is essentially useless; the explosion of a standard round is not enough force to even propel the bullet out of the gun barrel!) Low Gravity: A gravity rating of less than -1 is generally not fatal to humans, although babies born and raised in a low-gravity or weightless environment will grow up to be very thin and frail, and will not be able to function in a normal, 1G gravity setting. For this reason, while manned bases can certainly be built on low-G worlds, settlements with permanent populations are not advised. Most technology can be manufactured more easily in a low-G or weightless environment, especially devices with very tiny parts, or that require very high levels of precision. Spaceships, for example, are almost always constructed outer in space, in a zero-G, airless environment, and some player inventions might, at GM's discretion, require a low-G environment to construct or even research! Optional Combat Rules: If combat is taking place in a low-G environment, ranges for all ballistic and missile weapons increase by the planet's gravity rating times -10% (I.E. a machine gun fired on a planet with a Gravity Rating of -5 has 150% its normal range.) Weapons that rely on volleys of indirect fire, such as mortars or grenade launchers, may not function correctly if the planet's gravity is extremely low, I.E. -8 or less, with lobbed shells flying off into space or at least into orbit instead of arcing to the ground. Gravity is based entirely on the planet's mass, and cannot be altered in any way, though a player might develop technology such as personal exoskeletons, reinforced robot drones, or antigravity generators, that would allow them to exploit resources on an otherwise too-heavy planet. Indigenous lifeforms on a high-G world tend to be stronger and tougher than their earthly counterparts, and indigenous lifeforms on a high-G world tend to be thinner and frailer. Optional Rule: Add 5% per Gravity Rating to a creature's hit points if it is native to a high-gravity world; subtract 5% per negative Gravity Rating if it is native to a low world.

Radiation Level (-10 to +10 range) This represents the amount of light, heat, and other solar radiation a planet receives from its sun, as well as background radiation from radioactive materials. Radiation Level is increased with a planet's proximity to its sun, and decreased by its Atmosphere Rating, although at GM's discretion, occasionally an unusually high concentration of radioactive materials in a planet's crust can cause higher-than-expected radiation levels- a valuable resource find, if only the player can figure out a way to let his miners survive the extraction process. (Note that radioactive space phenomena such as neutron stars irradiate entire solar systems, and thus planets near such a radiation source will most likely be skipped and not be explored.) Low radiation is generally not a problem for humans, as long as the temperature is warm enough for survival, and there is enough light to see. High radiation, however, can cause problems very quickly. In a +1 to environment, humans tend to tan and sunburn very easily if their skin is exposed to unfiltered solar light. Radiation Levels of +2 or higher will also cause markedly increased incidence of cancer, especially skin cancer, and possibly other mutations, as well. Radiation Levels of +5 or higher will cause, at worst, radiation poisoning, a gristly slow death, or at best cook a person alive. Standard terraforming techniques cannot directly decrease a planet's radiation level, although bombarding a planet with radiation beams or detonating a nuke or two could easily increase it, at least in the targeted areas. Radiation from such hotspots tends to spread gradually into surrounding matter over a long period of time, until equilibrium is reached. Players might eventually be able to develop radiation filtering techniques, or various large-scale ways of blocking solar radiation, but the simplest solution is to simply insulate both vehicles and personal suits against radiation with lead or other heavy metal plating, or better still, stay out of highly radioactive areas altogether. Note: since radiation is one major cause of mutation, planets with higher radiation levels tend to host more diverse lifeforms, assuming the radiation isn't so high that the landscape is sterilized.

Water Level (-10 to +10 range) This value represents how much of a planet's surface is covered with water. A value of -10 means the planet has little or no liquid water, and a value of +10 means the planet is one vast ocean, with all of its land masses underwater. Pretty much any other value will yield at least a little arable land, depending on the topography and local weather patterns. Earth's Water Level according to this system is +4, or about 70%. Standard terraforming equipment can gradually raise or lower a planet's water level by adjusting gasses in the atmosphere, seeding clouds, and manipulating terrain to influence weather patterns. And if enough freighters were used to ferry water, water could be introduced to a dry planet with an appropriate temperature and atmosphere, or a high ocean level could be slowly drained. Usually, however, it's not worth the effort. Likewise, undersea bases could be constructed on ocean worlds, and settlements with atmospheric condensers could be set up on arid worlds, but the player would need to develop this technology, so again, it's seldom worth the effort. Only the most mineral-rich worlds, or planets in the most barren and uninhabitable of campaign universes, would be merit such treatment.

Temperature Range (-10 to +10 range)
-10: Too cold. +10: Too hot. 0: Just right! -5 to +5 are survivable by humans, but range from annoying to brutal for off-worlders to endure. Temperature is linked to radiation level, and is controlled primarily by the planet's proximity to the sun. Self-contained settlements can be built in extremely hot or cold environments, and robot drones don't care about the temperature, but again, the player has to research and develop all this stuff. Terraforming tools can mildly influence a planet's temperature by adding gasses to the atmosphere to either block or trap solar heat. Planets themselves typically have hot and cold areas, hot and cold seasons (depending on the axis tilt), and are hotter during the day and colder at night. If a planet's rotation axis is roughly parallel with its revolutionary axis, it will tend to be warmer at the equator and cooler at the poles. As Earth's own extremely diverse life demonstrates, indigenous life forms may exist in environments too hot or cold for humans to handle.

Minerals (1% to 20% range)
This is a rating of how rich a planet is in metals, valuable minerals, and other natural resources. Not all planets contain the same kinds of minerals, of course, but for simplicity's sake, the game assumes that a player's mining colonies together target and extract roughly the ratio of minerals that the player's industries need. This figure represents how much of the planet's crust contains minerals in deposits significant enough that mining them will produce a profitable ore. Mineral Rating steadily decreases as a player successfully mines a given planet. The Mineral Rating is a percentage; the actual amount of ore depends on a planet's mass, and the rate of extraction depends on the number of mining colonies the player Builds there. The maximum number of mines a planet can support depends on its surface area (size) and on whether or not the player has built any other settlements on it.

Size (in kilometers or miles diameter or something; affects minable area and arable land)

Mass (distinct from size; affects gravity and Mineral Rating)

Type (gas giant, rocky world, icy world)

Day (in GSDs or GSHs)

Year (in GSYs or GSDs)

Moons (number, sizes, orbital periods) Moons also have a mineral rating of 1-20. However, since they are by definition less massive and smaller than the planets that they orbit, they are usually less worthwhile to mine. Since they have low masses, they usually also have low gravity and few have a strong atmosphere. However, lunar settlements are often cheaper and more convenient for some purposes than building an artificial satellite.

Axial Tilt (degrees; determines #, severity of seasons)

Biodiversity: This is a measure of the variety and complexity of indigenous life forms on a habitable planet. (rating of 0 (no life), 1 (fossilized bacterial remains), 2 (primordial soup), 3 (active microorganisms), 5 (prevalent aquatic plant life), 10 (fish and insect species), 15 (first evolutionary path beyond sea life; I.E. amphibian and reptilian life on Earth), 20 (A more advanced species; I.E. birds on Earth), 25 (A third major evolutionary path diverges; I.E. mammals on Earth), 30 (present-day Earth), and beyond?

To determine biodiversity: Water must be greater than 1; Radiation must be greater than -10 and less than +5. Temperature Range must be between -5 and +5 somewhere on the planet's surface throughout the entire year. Atmosphere must be greater than -9 and less than 9. If your planet meets these criteria, Roll a D20. If you roll a 20, roll again ONCE and add the two rolls together. Do not roll a third time even if the second roll comes up 20.) Now add the planet's Radiation Level, and then subtract the difference between your Atmosphere rating and 0. (I.E. if your Atmosphere Rating is 5 or -5, subtract 5.) If it fails one or more of these criteria, the planet is either completely sterile, or has a rating of 1.

1D20 (explodes ONCE on 20) + Rad - | Atm |

Optional Biodiversity Rule: Life on all these alien planets doesn't necessarily have to develop the same way as Earthly life, even if it is based on DNA. For simplicity's sake, first assume that oceanic, plant, and insect life develops similar to Earthly life. For every 5 points after a Biodiversity of 10, a new evolutionary path develops, based on one of the older patterns with one or more fundamental changes. If a planet has a biodiversity 15 or higher, but no dry land, then assume a remarkably different type of sea life evolves. Each new type of animal should have some distinct feature that gives it an advantage over other life forms, I.E. a more complex heart, a different way of circulating blood, a new way of living in a vastly different habitat, a way of processing new types of food, etc. Each time a new phylum evolves in this manner (every 5 points beyond 10,) roll a D20. If the result is a 20, one species of that new type of creature that just evolved has also developed the capacity for abstract thought. If 5 more points of evolutionary growth pass while this species is alive, it becomes as intelligent as humans, although it may process information differently than humans and may not be able to communicate or use tools. Introducing other humanoid races, and especially other space faring races, can be an enormous amount of work for the GM, and so the decision to add one to your game should be a carefully considered one, and should not be based on a die roll.

Possibly add up Atmos, Grav, Rad, Water, Temp, Minerals to determine)

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