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The worlds of the Wing Commander Universe aren't very well defined in terms of general information. The positions of a few of them are known (worlds like Earth, Kilrah, Firekka, Warsaw, Locanda IV, Oxford, etc.), but few of their actual characteristics are to be found in any piece of Wing Commander canon. It thus may be quite often that a GM is faced with the need to generate data on a specific world for an adventure. The procedure for creating planetary data from scratch is fairly long. This is necessary, unfortunately, since planets require the generation of a good deal of data that's used for determining environmental effects as well as for setting several parameters used in intraplanetary transits (see Chapter 8.2). The world creation procedure as outlined in this sub-Chapter is designed to allow planets to be created as quickly and as easily as possible without skipping over any required data. For purposes of this discussion, all worlds will be called "planets" regardless of whether they are planets, moons, moonlets, asteroids, etc. Also, the terminology used in the discussion will assume that the planet to be created is a brand new world (as opposed to an existing world that simply needs data generated for it). All planets will use the Planet Record Sheet (available in Appendix Two) in order to record their vital statistics. The use of a calculator is recommended for certain steps in this procedure (as with the full system creation procedure), though it's not strictly necessary to use one.

The procedure for generating data for a specific planet is as follows:

  1. Determine the planet's type and orbital position.
  2. Determine the planet's size, mass and gravity.
  3. Determine the planet's atmospheric density.
  4. Determine the planet's axial tilt and surface temperature range.
  5. Determine the severity of the planet's tectonic activity.
  6. Determine the planet's atmospheric composition.
  7. Determine the planet's hydrospheric composition.
  8. Determine the planet's lithospheric composition.
  9. Determine the planet's biodensity and mineralogical density.
  10. Determine the severity of the global weather.
  11. Determine the length of the planet's day and year.
  12. Determine the planet's value as a colonizable world.
  13. Determine the planetary geography.
  14. Create lifeform lists for the planet (if necessary).
  15. Create a number of communities for the planet (if necessary).
  16. Locate the world's Lagrange Points (if necessary).

EDITOR'S NOTE: The system for generating planetary data used in WCRPG aims to be as physically realistic as possible. However, it should be noted that the game's editors are building a game, not a full-fledged working solar system model. The procedure as outlined below will enable a creator to generate data on planets quickly, but will leave out a lot of the details of planetary physics. For those creators out there who want to use a more realistic planet-building model, there are freeware programs available on the Internet that can create planets with more realistic physics. Creators are more than welcome to use these programs, though it will be necessary to convert the end results of their use into terms compatible with WCRPG.

Determine the planet's type and orbital position.

The first thing that needs to be determined about a planet is its type and orbital position. Type in this case refers to the planet's surface classification. There are five general planetary types:

  • Liquid planets have a surface that is at least half-covered by a liquid substance (including water). Liquid planets are commonly found in and around a star's ecosphere and are the most likely type of planet to house life.
  • Molten planets have a surface that is at least half-covered with lava flows or molten rock. These planets experience extreme vulcanism, usually due to significant tidal forces upon the planet's surface. They are most commonly found in the orbital lanes preceding the system's ecosphere.
  • Frozen planets are so cold that whatever water does exist on the planet's surface is most commonly in the form of ice. Frozen worlds are mainly lifeless balls of ice found in a system's outerzone, though a few can be found within the ecosphere. Some of these latter frozen worlds are even capable of supporting life.
  • Gas Giants are large worlds composed primarily of gases, usually a mixture of hydrogen, helium, and ammonia. They have poorly defined solid or liquid cores. As a rule, these planets are usually massive and therefore have a high gravitational pull at their "surface". Because Gas Giants have no clearly-defined surface, it is impossible to actually land on a Gas Giant; the attempt is inevitably lethal for any being dumb enough to attempt it. However, it is possible for a craft to remain in the upper atmosphere of such a world for an extended period of time.
  • Rock planets fail to meet the definition of a Liquid, Molten or Frozen planet but still have a solid surface. Because of their ambiguous definition, Rock worlds have highly variable conditions. Some may be completely lifeless, with cratered a surface and no atmosphere. Others may be Earth-like planets in all respects aside from surface water coverage.
Cy sysdata

Information on a star system on the Planet Record Sheet.

A planet creator will need to select one of these five types for their world and record it in the appropriate box on the Planet Record Sheet along with the planet's orbital position within the system, assuming these parameters haven't already been determined during the star system creation process. The planet's orbital position refers to its general location in the system relative to a region of space within the system where conditions are favorable for life as it may be found on Earth, known as the system's ecosphere. Planets may either be within the ecosphere, in the hot orbital region preceding it (also known as the pre-ecosphere or the innerzone), or the cold orbital region following it (the post-ecosphere or outerzone). The position of a system's ecosphere depends upon the effective luminosity class of its primary (for more details, see Chapter 10.2.3). The planet's position within a star system will set many of its details, such as surface temperature classifications (which ultimately helps to determine planetary weather). Not every planet type can exist in every zone; creators who are designing their planet independently of an intended star system should refer to the guidelines in Chapter 10.2.3 when selecting its type and location.

To aid first-time planet designers, two examples of planet creation will be included at the end of each step in this procedure. We'll use the system created in the previous Chapter to set the initial configuration for our examples. The first example will go through the process of creating an Earth-like planet (keeping with the examples from the previous chapters, this will be the agricultural world of Cyvuspe), while a Frozen world will be created in the second example (the single large moon of the outlying gas giant in the system, which we'll name "Lolydu"). The Frozen world will utilize random die rolls, while arbitrary selections will be made for Cyvuspe.

Cy basicdata

Basic Info for Cyvuspe.

Since we're using the full Cyvuspe system model, the types and positions of our worlds have already been set. Cyvuspe is a Liquid world located 1.009 AU from the barycenter of a G2/M0 binary star system. Lolydu is a moon orbiting the system's Gas Giant (which we'll name "Nycalca"), the only moon of significance orbiting it. It is a Frozen World in the second lunar orbital lane around Nycalca, which itself is located 15.265 AU from the system's barycenter. Note that the actual distance from the star is only of moderate importance; Cyvuspe could easily be set anywhere in a star system's ecosphere, while Lolydu could be set anywhere past the system's Frost Line. This would be the case regardless of the actual configuration of the system.

Determine the planet's size, mass and gravity.

With information on the planet's type and position in hand, size should be the next thing determined. The planet's size will help the designer determine its mass and gravity. Gravity directly affects a planet's atmospheric density as well as the severity of the planet's weather. Mass is a largely cosmetic parameter, though it is an essential piece of information if the exact positions of the world's Lagrange points are to be determined.

Planets are massive objects that use their own Size Class scale (though this scale is merely a continuation of the vehicle-scale Size Class scale (see Chapters 6.2 and 7.2), with Vehicle Size Class 50 corresponding exactly to Planet Size Class 0). The range of possible sizes for a planet depends largely on its type and where exactly it falls within a star system. Most planets fall into the general category of "non-gas giant", which (as it sounds) indicates any planet type other than a Gas Giant (i.e. a Liquid, Frozen, Molten or Rock world). Within these basic types, planets may be terrestrial worlds (main planets within an orbital lane), dwarf planets (a small planet that has not cleared its neighboring region of planetesimals), moons (a body that is a natural satellite of another body) or moonlets (a particularly small moon). As with vehicles and starships, Size Classes are dependent upon a specific bounding box volume. This volume is the minimum size a rectangular prism (a box) would have to be in order to fit the whole planet inside of it. A planet is said to be of a certain Size Class as long as it is at least as large as the minimum required volume for that Size Class.

Another factor that affects a planet's mass and gravity is its density, or the amount of mass contained by the planet over the entirety of its volume. Aside from affecting its mass and gravity, a planet's density will help to determine its overall mineralogical content, so it's an important measurement. Planetary densities are usually measured as a multiplier of "Earth Densities"; one Earth Density equals the density of the Earth (5,515 kg/m3 for the curious or for those keeping exact statistics). As a general rule, objects are denser the closer they are to their system's primary (though there are exceptions when it comes to moons). Gas Giants aren't very dense at all; some (such as Saturn) would theoretically be able to float in water.

A planet creator may use the following table in order to determine the size and density of a planet. The creator may select a size and density value that's appropriate for the type of world they are creating and record those values in the Planet Record Sheet. Alternatively, they may make the die rolls indicated in the table. If a creator is attempting to make a non-gas giant and cannot decide upon whether to make it a terrestrial world or a dwarf planet, the creator may roll 1d10 and compare the result to the number of the orbital lane of the planet in question. The planet is a dwarf planet if the result of the roll is less than the value of the orbital lane and a terrestrial world otherwise. For example, the planet creator is building a world in the system's fifth orbital lane. A d10 roll comes up as 4, so the planet will be a dwarf planet. A similar procedure can be used to determine moons versus moonlets in those cases where a creator has the option for either; a roll result less than the value of the lunar orbital lane indicates a moonlet. In those cases where the creator is building their planet independently of a star system, a roll of four or less indicates a dwarf planet. Dwarf planets should be accompanied by either a dust belt or an asteroid belt in the same orbital lane; roll 1d10 to determine which (a result of 0-3 indicates a diffuse dust belt, 4-6 indicates a dense dust belt, and 7-9 indicates an asteroid belt). If the creator is making a star system without hazards, they should use terrestrial worlds only (i.e. no dwarf planets).

Random Determination of Planetary Size and Density
Planet Type Size Class Range Roll Density Range Roll
Moonlet
(Non-Gas Giant)
1d5-1
(0-4)
0.30+(1d10*0.05)
(0.3-0.75)
Moon
(Non-Gas Giant)
1d10+5
(5-14)
0.30+(1d10*0.05)
(0.3-0.75)
Dwarf Planet
(Non-Gas Giant)
6+1d5
(7-11)
0.30+(1d10*0.05)
(0.3-0.75)
Terrestrial Planet
(Non-Gas Giant)
13+1d10
(13-22)
0.75+(1d10*0.05)
(0.75-1.2)
Gas Giant 23+1d10
(23-32)
0.05+(1d10*0.05)
(0.05-0.5)

The creator has the information they need in order to determine their planet's mass and gravity once they have its size and density values set. They will simply need to reference the table below and read across the row corresponding to their planet’s Size Class to find base values for the planet's mass and gravity, multiply those values by the planet's density value, and record the final results in the appropriate boxes on the Planet Record Sheet. Additionally, each Size Class has a Roche Limit, an Outer Lunar Limit (which may be used to determine the final position of any moons orbiting the world), and a "mineral bonus" associated with it (which will be used to determine the planet's mineralogical density later on in the procedure). These three values will also need to be multiplied by the planet's density, rounded to the nearest integer, and recorded for later use. For reference purposes, the table includes a listing of real life objects (mostly in Earth's solar system) that fall within the various Size Classes.

WCRPG Planet Size Class Conversion Chart
Size Class Bounding Box Volume (m3) Mass (Earth Masses)
(Earth Density)
Gravity (gees)
(Earth Density)
Roche Limit (km) Outer Lunar Limit (km) Mineral Bonus Example
0 2.58E+15 0.000002 0.01 850.83 6,806.65 -20 Himalia
1 5.15E+15 0.000005 0.02 1,071.29 8,570.30 -19 Phoebe
2 1.03E+16 0.000010 0.02 1,349.74 10,797.91 -19
3 2.06E+16 0.000019 0.03 1,700.56 13,604.51 -19 Mimas
4 4.12E+16 0.000038 0.03 2,142.58 17,140.61 -19 Enceladus
5 8.25E+16 0.000076 0.04 2,700.57 21,604.54 -19
6 1.65E+17 0.00015 0.05 3,402.50 27,220.02 -18
7 3.30E+17 0.00031 0.07 4,286.88 34,295.08 -18 Tethys
8 6.60E+17 0.00061 0.08 5,401.14 43,209.09 -17 Dione
9 1.32E+18 0.0012 0.11 6,805.00 54,440.04 -17 Rhea
10 2.64E+18 0.0024 0.13 8,573.77 68,590.15 -16
11 5.28E+18 0.0049 0.17 10,802.27 86,418.18 -15 Triton
12 1.06E+19 0.0097 0.21 13,627.17 109,017.38 -13 Europa
13 2.11E+19 0.019 0.27 17,142.12 137,136.99 -11 Luna
14 4.22E+19 0.039 0.34 21,597.72 172,781.78 -9 Mercury
15 8.44E+19 0.078 0.43 27,211.42 217,691.40 -6 Mars
16 1.69E+20 0.156 0.54 34,297.78 274,382.25 -3
17 3.38E+20 0.312 0.68 43,212.50 345,699.98 2
18 6.76E+20 0.624 0.86 54,444.33 435,554.68 7 Earth
19 1.35E+21 1.250 1.08 68,561.72 548,493.78 14
20 2.70E+21 2.496 1.36 86,382.36 691,058.86 23
21 5.40E+21 4.992 1.71 108,834.95 870,679.60 34
22 1.08E+22 9.983 2.16 137,123.44 1,096,987.56 49
23 2.16E+22 19.933 2.72 172,764.71 1,382,117.72 N/A
24 4.32E+22 39.866 3.42 217,669.90 1,741,359.21 N/A Uranus
25 8.65E+22 79.899 4.31 274,352.65 2,194,821.23 N/A
26 1.73E+23 159.799 5.43 345,662.68 2,765,301.47 N/A
27 3.46E+23 319.933 6.84 435,507.69 3,484,061.53 N/A
28 6.92E+23 639.866 8.62 548,705.31 4,389,642.47 N/A Saturn
29 1.38E+24 1,278.057 10.87 690,658.71 5,525,269.67 N/A Jupiter
30 2.77E+24 2,652.814 13.69 871,225.12 6,969,800.92 N/A
31 5.53E+24 5,108.878 17.25 1,097,014.01 8,776,112.08 N/A
32 1.11E+25 10,217.755 21.73 1,383,815.28 11,070,522.28 N/A
33 2.21E+25 20,435.512 27.38 1,740,876.20 13,927,009.61 N/A Proxima Centauri
34 4.43E+25 40,871.022 34.49 2,195,019.45 17,560,155.58 N/A
35 8.85E+25 81,742.044 43.46 2,764,510.35 22,116,082.81 N/A
36 1.77E+26 163,651.591 54.76 3,483,064.78 27,864,518.28 N/A
37 3.54E+26 32,663.166 68.99 4,388,386.64 35,107,093.12 N/A
38 7.08E+26 654,941.374 86.92 5,529,020.70 44,232,165.62 N/A Sol
39 1.42E+27 1,308,207.705 109.51 6,972,682.85 55,781,462.77 N/A
40 2.83E+27 2,613,065.327 137.98 8,774,706.70 70,197,653.59 N/A
41 5.67E+27 524,881.072 173.84 11,061,944.70 88,495,557.63 N/A Zeta Ophiuchi

Note that this procedure will produce a planet that has a reasonable mass and gravity for the minimum volume of a planet of the same Size Class. It may be that a creator wants to create a planet with a slightly larger volume. In that case, the creator will need to use the following formulas to find the planet's gravity and mass, solving them in the order presented:

planetary radius = ((3 * planetary volume) / (4π))(1/3)
absolute mass = (((density * 5515) * 4π * (planetary radius)3) / 3)
mass = absolute mass / 5.97*1024
gravity = (6.67x10-11 * absolute mass / (planetary radius)2) / 9.803
Roche Limit = 10 * planetary radius
Outer Lunar Limit = 80 * planetary radius

The respective results of these formulae should all be rounded to two decimal places. If the creator ascertained their final mass off of the table and would like to determine the absolute mass of their planet in kilograms, they may simply multiply their mass value by 5.97*1024. If the planet creator is attempting to build a colonizable planet, their world must have a surface gravity of no greater than two gees. For the world to be optimal, gravity should be somewhere between 0.8 and 1.2 gees.

We've stated that Cyvuspe is going to be similar to Earth. Checking the Size Class table above, we see that Earth is a PSC 18 object. We'll assume Cyvuspe has the same density as Earth, so we can just use the minimum given values straight from the table. Cyvuspe has a mass of 0.624 Earth Masses (roughly 3.73*1024 kilograms) and a gravity of 0.9 gees (the table actually says 0.86, but we'll go ahead and round that value to one decimal place for the hell of it). Those are a little lower than Earth's values, but still acceptable for our purposes. Any fitness gurus that live there might like the fact that they'll weigh a little less...

The indicated mineral bonus for Cyvuspe will be +7 according to the chart. Since the planet's density is the same as Earth, that value doesn't get modified. We'll record +7 for the planet's mineral bonus, which we'll use later on. Finally, we know that Cyvuspe has a Roche Limit of 54,444 kilometers and an Outer Lunar Limit of 435,555 kilometers, though that isn't helpful information in this case as it has already been established that the world has no moons.

We've placed the Frozen world of Lolydu in a lunar orbital lane and have already established that it's a moon. Checking the chart, we'll need to roll 1d10 for its Size Class and another 1d10 its density. The size roll comes up as one; its Size Class will be PSC 6 (5+1 = 6). The density roll comes up as a seven, so Lolydu's density is 0.65 Earth Densities (7*0.05 = 0.35; 0.30 + 0.35 = 0.65). It's a relatively small moon and not particularly dense; the density is close to that of Io, though it's about a third of Io's overall size. That could lend itself to some planetary vulcanism later down the road.

Checking for PSC 6, the base values are 0.00015 Earth Masses and 0.05 gees. We'll multiply both values by 0.65 to get the final values (after rounding): Lolydu's mass is 0.0000975 Earth Masses (or 5.82x1020 kilograms) and its surface gravity is 0.03 gees. The mineral bonus for PSC 6 is -18; this value also gets multiplied by 0.65 and then rounded to the closest integer (-12 in this case). We'll record this value for later use. Finally we can figure up Lolydu's Roche Limit and Outer Lunar Limit (though once again we will ultimately need neither value); the Roche Limit is 2,212 kilometers and the Outer Lunar Limit is 17,693 kilometers.

Determine the planet's atmospheric density.

Once a planet's surface gravity has been determined, it becomes possible to determine its categorical atmospheric density. This is a measure of how thick a planet's atmosphere is and has an effect on both the planet's temperature range and the severity of its weather. The categorical atmospheric density may also be used by a GM during the course of an adventure to determine things such as whether or not the planet's surface is subjected to a great deal of cosmic radiation.

The following table is used to determine a planet's atmospheric density. The creator will need to find the column that corresponds to the planet's surface gravity and make a 1d10 roll (except in the case of Gas Giants; those worlds always use the ">2.0" column regardless of their actual surface gravity). The row that intersects the gravity column at the cell that contains the result of the d10 roll will indicate the planet's categorical atmospheric density. The creator will need to record the indicated atmospheric density with the planet's stats. Additionally, the far right column of the same row indicates a "weather factor", which will be needed when the time comes to determine the severity of the planet's weather. The creator will simply need to record this value for later use.

Atmospheric Density based on Surface Gravity and d10 Roll
Density Class <0.2 0.2-0.5 0.5-0.8 0.8-1.3 1.3-2.0 >2.0 Weather Factor
None 0-9 7-9 9 N/A N/A N/A N/A
Very Thin N/A 3-6 8 N/A N/A N/A 1
Thin N/A 0-2 3-7 8-9 9 N/A 2
Moderate N/A N/A 0-2 2-7 7-8 N/A 3
Thick N/A N/A N/A 0-1 0-7 5-9 5
Very Thick N/A N/A N/A N/A N/A 0-4 10

We'll give Cyvuspe a Moderate atmospheric density; that seems bio-friendly, and it's the most likely outcome of the die roll for its gravity anyway. The weather factor for that atmospheric density category is 3.

Lolydu has a gravity of 0.03 gees. This is less than 0.2 gees, so we know what the outcome is going to be, but we'll roll the 1d10 anyway; we come up with a six. Checking the table, this corresponds to an atmospheric density of None and no weather factor at all.

Determine the planet's axial tilt and surface temperature range.

Once the planet's atmospheric density has been determined, its categorical surface temperature range may also be determined. A planet's surface temperature range is dependent upon two main factors: the planet's atmospheric density and its relative position within a star system. Perhaps not surprisingly, temperature has a key role to play in determining global weather severity.

Cy indices

A decent looking planet...

Temperatures in the Wing Commander Universe are given as a categorical set (as opposed to a specific range of temperatures). The categories are as follows:

  • Subarctic: These are very cold temperatures that are below what can usually be found in Earth's polar regions, ranging from absolute zero (-273°C) up to -100°C. Subarctic temperatures are common on outerzone worlds.
  • Arctic: These are cold temperatures that are common in Earth's arctic regions. They range from -100°C up to the freezing point of water (0°C). Arctic temperatures are common in the outer ecosphere lanes, but can be experienced anywhere in the ecosphere or post-ecosphere.
  • Temperate: These are generally mild temperatures favored by most lifeforms, usually found in Earth's middle latitudes. These temperatures range from 0° C up to room temperature (25° C). Temperate temperatures are common throughout a star system's ecosphere.
  • Tropical: These are usually warmer but still tolerable temperatures usually found in Earth's lower latitudes and desert regions. The temperature range for this category is from 25°C up to 50°C. Tropical temperatures are common in the inner ecosphere lanes, but can be experienced anywhere in the ecosphere.
  • Searing: Searing temperatures are too hot to support most lifeforms but still below the boiling point of water, between 50°C and 100°C. Searing temperatures are common in the outer innerzone, though occasionally they may be seen within a system's ecosphere.
  • Inferno: These are extremely hot temperatures greater than the boiling point of water (100°C) all the way up to around 2000°C (though technically there is no upper bound to this category). Inferno temperatures are common in the pre-ecosphere, particularly in the inner ecosphere and near the radius of a star's Roche Limit. Particularly high Inferno-level temperatures may pose a significant thermal damage hazard to spacecraft.

To determine the surface temperature range, a creator will use the table below. Each row of the table corresponds to a potential planetary position within the system relative to the system's critical radii in AU and contains a formula. The formulas use the following set of shorthand notation: "O" is the planet's orbital distance from the primary in AU, "RL" is the system's Roche Limit, "IER" is the Inner Ecosphere Radius, "OER" is the Outer Ecosphere Radius, and "FL" is the Frost Line Radius. The creator needs to determine the row for which the solution is true, and find the intersection of that row with the column that corresponds to their planet's atmospheric density; the intersection will indicate the planet's surface temperature range. Once the intersection has been located, the creator simply needs to write down the indicated temperature range with the planet's stats. Note that some information about the system's configuration needs to be known in order to perform this step; creators may select their world's location arbitrarily if necessary.

Planetary Temperature Range based on Atmospheric Density and Planetary Position
Position None Very Thin Thin Moderate Thick Very Thick
Pre-Ecosphere
(IER-O)/(IER-RL) > 0.5
Subarctic to Inferno Inferno Inferno Inferno Inferno Inferno
Pre-Ecosphere
(IER-O)/(IER-RL) ≤ 0.5
Subarctic to Inferno Searing to Inferno Searing to Inferno Searing to Inferno Inferno Inferno
Ecosphere
(OER-O)/(OER-IER) > 0.75
Subarctic to Inferno Tropical to Inferno Tropical to Inferno Tropical to Inferno Searing to Inferno Inferno
Ecosphere
(OER-O)/(OER-IER) > 0.5 and ≤ 0.75
Subarctic to Searing Temperate to Searing Temperate to Searing Temperate to Searing Searing to Inferno Inferno
Ecosphere
(OER-O)/(OER-IER) > 0.25 and ≤ 0.5
Subarctic to Searing Subarctic to Searing Arctic to Searing Arctic to Searing Temperate to Searing Tropical to Searing
Ecosphere
(OER-O)/(OER-IER) ≤ 0.25
Subarctic to Tropical Subarctic to Tropical Subarctic to Tropical Arctic to Tropical Temperate to Searing Temperate to Tropical
Post-Ecosphere
(FL-O)/(FL-OER) > 0.5 and ≤ 1.0
Subarctic to Temperate Subarctic to Temperate Subarctic to Temperate Subarctic to Temperate Arctic to Tropical Temperate to Tropical
Post-Ecosphere
(FL-O)/(FL-OER) > 0 and ≤ 0.5
Subarctic to Arctic Subarctic to Arctic Subarctic to Arctic Subarctic to Arctic Arctic to Temperate Arctic to Temperate
Post-Ecosphere
(FL-O)/(FL-OER) ≤ 0
Subarctic Subarctic Subarctic Subarctic Subarctic to Arctic Subarctic to Arctic

Planet creators that wish to build colonizable worlds for use in their adventures should bear in mind that a planet's surface temperature range need only contain the Temperate or Tropical categories (i.e. their planet may have a temperature range hotter or colder than either category, as long as least one of the two is present). T

As a general rule, the greater the surface temperature range, the more of an effect it will have on the planet's weather (this is based on actual meteorological principles; sharper contrasts in temperature lead to stronger weather systems, which lead to more intense weather). Once a creator has determined the surface temperature range for their planet, they'll need to determine how much it will affect the planet's weather. To determine the effect, a creator need only to look up their planet's surface temperature range in the table below and record the indicated weather factor value for later use.

Weather Factors for Planetary Temperature Range
Temperature Range Weather Factor
Arctic to Searing 4
Arctic to Temperate 2
Arctic to Tropical 3
Inferno 0
Searing to Inferno 3
Subarctic 0
Subarctic to Arctic 3
Subarctic to Inferno 10
Subarctic to Searing 8
Subarctic to Temperate 6
Subarctic to Tropical 6
Temperate to Searing 2
Temperate to Tropical 1
Tropical to Inferno 4
Tropical to Searing 1

Planets with no atmospheric density have no atmosphere and therefore no weather. If the planet being created has no atmosphere, the weather factor for temperature may be ignored (though the planet will still have the surface temperature range generated in this step of the procedure).

The planet's degree of axial tilt (the angle between the world's axis of rotation and plane of revolution) should be determined after the surface temperature range has been set. Axial tilt is a largely cosmetic stat, but it can be used by a GM to track the severity of global seasonal surface temperature variations. To determine a world's axial tilt, the creator merely needs to roll 2d5. If the result is 10, the creator will roll d% next; they will perform a second 2d5 roll in all other cases. In either case, the second roll is added to the result of the first roll, and the final sum sets the world's axial tilt (in degrees).

We know that Cyvuspe is located in the ecosphere and Lolydu is in the post-ecosphere beyond the Frost Line. The system's Inner Ecosphere Radius (determined in the example from the previous Chapter) is at 0.839 AU and the OER is at 1.292 AU, with Cyvuspe itself orbiting at 1.009 AU; it has a Moderate atmospheric density as established earlier in the procedure. We perform the necessary calculation for an ecosphere world and arrive at a check value of 0.625 ((1.292-1.009)/(1.292-0.839) = 0.283/0.453 = 0.625). Checking the tables for the ecosphere solutions, we can see that this corresponds to the second ecosphere row; with a Moderate atmospheric density level, we can see that its temperature range will be Temperate to Searing, which has a weather factor of two (overall, this is a reasonably close match for Earth, though Earth would probably be considered Arctic to Searing). We'll go ahead and set the world's axial tilt to be about the same as the Earth, 19 degrees. Lolydu (at 15.265 AU) is well past the Frost Line (located at 2.001 AU). The check value will obviously be negative as a result, so we know this will be the bottom row without doing much in terms of calculation. With an atmosphere density of None, a Subarctic temperature range is assured (which has a weather factor of zero). We'll record the temperature ranges for both worlds along with their respective weather factors for later use. Finally, we'll roll 2d5 for Lolydu's axial tilt; a nine comes up, so we roll 2d5 again and get another nine. Lolydu will have an 18 degree axial tilt (9+9 = 18).

Determine the severity of the planet's tectonic activity.

The next step in a planet's creation is to determine its level of tectonic activity, or the severity and frequency of volcanic eruptions and earthquakes on its surface. Vulcanism in particular is a driving force that shapes a planet's evolution. Volcanoes play a big part in shaping a planet's surface by smoothing over areas that have been impacted in cosmic collisions (asteroids, comets and the like) with lava flows and/or volcanic ash. Many of the same forces that cause vulcanism also give rise to earthquakes, which aid in mountain building and as a result affect a world's overall climate. While both volcanic eruptions and earthquakes are commonly considered extreme natural disasters, their presence actually enhances the habitability of a world (though only if they don't occur too frequently). In WCRPG, both earthquakes and volcanoes are forms of tectonic activity, though they are considered separate elements (vulcanism and seismicity) and a high degree of one phenomenon does not necessarily imply a high degree of the other. This step of the planet building procedure only applies to non-Gas Giants; if the world being designed is a Gas Giant, it automatically has categorical values of None for both vulcanism and seismicity.

A world's categorical vulcanism level is determined by a simple 2d10 roll, the result of which is heavily modified depending upon the world's general type, gravity and location. To determine the modifier to the roll, begin by checking to see if the primary is exotic or not (i.e. if it is one of the possible outcomes listed in the "Exotic Results" table in the previous sub-Chapter). If it is, divide 400 by the result of a d10 roll and multiply the result by the planet's gravity, rounding that result to the nearest integer. If the primary is not exotic, divide 400 by a d% roll instead. (NOTE: If more than one world in the same system is being designed, this result should be recorded and re-used for all worlds in the system). The 2d10 roll may be further modifier as follows:

  • Add 5 to the result if the world has one full-sized moon, or if it is the moon of a Gas Giant.
  • Add 10 to the result if the world has more than one full-sized moon.
  • Add 50 if the planet is a Molten World.

After any modifiers have been added to the result of the 2d10 roll, the final result may be referenced on the following chart in order to determine the severity of the planet's vulcanism:

Categorical Vulcanism Severity by Modified 2d10 Roll
Modified 2d10 Result Categorical Severity Mineral Bonus Biodensity Bonus
≤16 None -20 -5
17-20 Light -10 +0
21-26 Moderate +0 +5
27-70 Heavy +10 -10
71+ Extreme +20 -20

More explicitly, the formula for determining vulcanism is as follows:

vulcanism index = round((400/(d10 -or- d%))*gravity) + 2d10 + other modifiers

Once the severity of the planet's vulcanism has been determined, it's possible to determine the severity of the planet's seismicity. To determine seismicity, another 2d10 roll is made, with the result of the roll modified depending on the severity of the world's vulcanism as follows:

  • Subtract 8 from the result if the world's categorical vulcanism is None.
  • Subtract 4 from the result if the world's categorical vulcanism is Light.
  • Add 4 to the result if the world's categorical vulcanism is Heavy.
  • Add 8 to the result if the world's categorical vulcanism is Extreme.
  • Subtract 4 if the world is a Frozen World.
  • Subtract 2 if the world is a Rock World.
  • Add 2 if the world has one full-sized moon.
  • Add 4 if the world has more than one full-sized moon.

Once the final result has been determined, it may be compared to the table below in order to determine the world's categorical seismicity level. Worlds that are PSC 15 or smaller automatically have a categorical seismicity level of None.

Categorical Seismicity Severity by Modified 2d10 Roll
Modified 2d10 Result Categorical Severity Mineral/Biodensity Bonus
<7 None -10
7-10 Light -5
11-14 Moderate +0
15-18 Heavy -5
19+ Extreme -10

Both the categorical vulcanism and seismicity severity levels have mineral and biodensity bonuses associated with them. The mineral bonuses should be tallied and added to any previous mineral bonuses from the planet's size and density. The biodensity bonuses should likewise be tallied and recorded for later use.

If the planet creator intends for their world to be colonizable, neither of its tectonic components may be Heavy or Extreme.

This will be one step in the creation of Cyvuspe for which we'll go ahead and do the die rolls. Neither star in the Cyvuspe system is exotic. We make our first 2d10 roll and follow it up with the d% roll we'll need for the modifier. The 2d10 roll comes up as 7 and the d% result is 27. The planet has 0.9 gees of surface gravity. It doesn't match any of the criteria for any of the other modifiers. Plugging in all that information into the vulcanism formula gives us a result of twenty (400/27 = 14.81, 14.81 * 0.9 = 13.3, rounds to 13, 13 + 7 = 20), so the world has Light vulcanism. We then make the second 2d10 roll for seismicity (we know that Cyvuspe is large enough that it can have earthquakes). Since the world has Light vulcanism, we know that we'll be subtracting four from the result; it meets none of the other modifier criteria. The die is cast and comes up as 11, so our final result is seven (11-4 = 7). Cyvuspe has both Light vulcanism and seismicity; this is somewhat different from Earth, but shouldn't make too much of a difference. The planet's seismicity categories add a total of -15 to its mineral bonus (which becomes -8 owing to the previous value of +7 given for its size and density) and a total of -5 to its biodensity.

Lolydu is a PSC 6 world with 0.03 gees of surface gravity, again located in a system with a non-exotic primary. We also know that it is a moon of a Gas Giant. The 2d10 roll comes up as 6. We'll recycle the 27 for the d% roll from Cyvuspe. The final result of the vulcanism roll once all the modifiers are accounted for is twelve (400/27 = 14.81, 14.81 * 0.03 = 0.57, rounds to 1, +5 for being the moon of a Gas Giant = 6, 6 + 6 = 12), so the world has no active vulcanism. Finally, since it is a PSC 6 world, it's too small to have any seismicity. Lolydu has both vulcanism and seismicity levels of None; it receives a -30 mineral bonus (now -48) and -15 biodensity bonus as a result.

Determine the planet's atmospheric composition.

Cy spheres

Gravity, Atmospheric Density, and the Three 'Spheres.

The next step in the planet creation process is to determine what gas mixture comprises the planet's atmosphere. In general, a planet's atmospheric mix can largely be predicted by surface conditions; this involves knowledge of the planet's atmospheric density as well as its position within a solar system. However, there may be other random factors (such as vulcanism or a non-standard surface configuration) that may drastically affect a planet's atmospheric composition, resulting in a number of possible "exotic" atmospheres.

Determining a planet's atmospheric composition is fairly simple. Provided the planet has an atmosphere, the creator will need to make a 1d% roll and look up the results in the tables provided (obviously, the mix is "None" if the planet's atmospheric density is None). If a result of "Exotic" occurs, the creator will need to make a second d% roll and refer to the second table for the final result. A planet's atmospheric mix does have an effect on the overall global weather. To reflect this, each gas mixture has an "atmospheric constant" listed in parentheses along with it. Once the final atmospheric mix has been determined, the creator will need to record that mix in the planet's stats and will need to record the atmospheric constant for later use.

Vulcanism has a chance of altering the resultant atmospheric composition. If the planet has a categorical vulcanism severity level of Heavy, roll d%; on a roll of 50 or higher, the level of vulcanism is sufficient to taint the atmosphere. Atmospheric tainting occurs automatically if the planet's vulcanism severity is Extreme. If the atmosphere is tainted, the creator must tack Sulfur Dioxide onto the atmospheric composition as the least common gas and add 2 to the planet's atmospheric constant. There are a few special cases: if the planet's main atmospheric component is Carbon Dioxide, change it to "Carbon Dioxide, Sulfur Dioxide (4)". Change it to "Chlorine, Sulfur Dichloride (6)" if Chlorine is the most common component, and "Fluorine, Sulfur Tetrachloride (7)" if Fluorine is most common.

Planet creators that wish to create colonizable planets for use in their adventures should bear in mind that a planet's atmosphere must contain Oxygen. Any gas combination that contains Oxygen is suitable for this purpose (though as a rule planet creators should avoid the "Oxygen, Hydrogen Cyanide" selection if they truly want to make the world habitable to any species; it is okay to use that mix for any race that has adapted to the presence of an otherwise extremely poisonous gas).

Atmospheric Composition Determination by Planetary Conditions and d% Roll
Planetary Conditions 00-50 51-70 71-80 81-94 95-99
Gas Giant Methane, Ammonia, Hydrogen (1) Methane, Ammonia, Hydrogen (1) Hydrogen, Helium (0) Hydrogen, Helium (0) Exotic
Pre-ecosphere World, or Ecosphere Frozen/Molten World
Very Thin Atmosphere
Hydrogen, Helium (0) Hydrogen, Helium (0) Hydrogen, Helium (0) Hydrogen, Helium (0) Exotic
Pre-ecosphere World, or Ecosphere Frozen/Molten World
Thin Atmosphere
Carbon Dioxide (1) Carbon Dioxide (1) Carbon Dioxide (1) Carbon Dioxide (1) Exotic
Post-ecosphere World
Any Density
Ammonia (1) Methane (1) Methane (1) Methane (1) Exotic
Pre-ecosphere World
Moderate Atmosphere or Denser
Carbon Dioxide (1) Carbon Dioxide (1) Carbon Dioxide (1) Carbon Dioxide (1) Exotic
Frozen World in Ecosphere
Moderate Atmosphere or Denser
Methane, Ammonia, Hydrogen (1) Methane, Ammonia, Hydrogen (1) Nitrogen, Oxygen (2) Nitrogen, Oxygen (2) Exotic
Molten World in Ecosphere
Moderate Atmosphere or Denser
Carbon Dioxide (1) Carbon Dioxide (1) Carbon Dioxide (1) Carbon Dioxide (1) Exotic
Liquid/Rock World in Ecosphere
Moderate Atmosphere or Less Dense
Nitrogen, Oxygen (2) Nitrogen, Oxygen (2) Nitrogen, Oxygen (2) Exotic Exotic
Liquid/Rock World in Ecosphere
Thick or Very Thick Atmosphere
Nitrogen, Oxygen (2) Nitrogen, Oxygen (2) Exotic Exotic Exotic
Exotic Atmosphere Mixture Determination by d% Roll
d% Result Atmospheric Mix Atmospheric Constant
00-12 Nitrogen 1
13-17 Carbon Monoxide 1
18-19 Fluorine, Carbon Dioxide 3
20-22 Nitrogen, Carbon Dioxide 2
23-24 Chlorine, Carbon Dioxide 4
25-29 Chlorine 2
30-34 Fluorine 1
35-39 Helium, Sodium 1
40-42 Nitrogen, Chlorine 3
43-47 Methane, Ammonia 1
48-49 Fluorine, Nitrogen 2
50-52 Ammonia, Hydrogen 1
53-54 Fluorine, Chlorine 3
55-59 Cyanoacetylene 2
60-62 Methane, Ammonia, Argon 3
63-64 Methane, Hydrogen Cyanide 2
65-67 Methanol, Ethanol 3
68-72 Oxygen 1
73-74 Oxygen, Carbon Dioxide 3
75-77 Oxygen, Hydrogen 1
78-82 Sulfane, Sulfur Dioxide, Sulfur Trioxide 6
83-87 Water Vapor 1
88-94 Oxygen, Water Vapor 2
95-97 Carbon Dioxide, Water Vapor 2
98-99 Oxygen, Hydrogen Cyanide 2

The obvious atmospheric mix for Cyvuspe would be Nitrogen/Oxygen, but for the hell of it let's go ahead and roll it out. Cyvuspe is a Liquid World within the Ecosphere and has a Moderate atmospheric density. This corresponds to the second-to-last row of the chart. A roll of d% comes up as 09, which indicates a Nitrogen/Oxygen atmosphere. Had it come up as an Exotic atmosphere, we would have rolled again...that d% roll came up as 04, indicating a Nitrogen atmosphere sans Oxygen. In either case, the planet's vulcanism severity level is not sufficient to taint the atmosphere. N2O2 is what we really want, so we'll just go with that.

Lolydu has no atmospheric density; because it has no atmospheric density, it has no atmosphere whatsoever, and so we can simply set its atmospheric mix to None.

Determine the planet's hydrospheric composition.

A planet's hydrospheric composition can be determined as soon as its atmospheric composition has been set. The term hydrosphere as it is used in WCRPG is a bit of a misnomer; in WCRPG, it refers to the compound(s) that make up any liquid portion of a planet's surface (the true definition of the term is "the combined mass of water found on, under, and over the surface of a rocky planet"; a great many planets don't have any kind of water on their surface or as part of their overall composition whatsoever). A planet's hydrospheric composition is largely dependent upon its atmospheric composition. Planetary temperature, vulcanism and atmospheric density may also factor in, though in most cases a planet's hydrosphere is solely dependent on its atmospheric mix. Planets that have no atmosphere have no hydrosphere. By definition, Gas Giants have no hydrosphere.

To determine the composition of a planet's hydrosphere, a creator needs to find its atmospheric mix on the table below and look up the results in the corresponding row. There can be up to three possible hydrospheric mixes for any given atmospheric mix. In the cases where there are multiple possibilities, the creator should check each possibility in turn. Each possibility is generally listed as a mix, a set of temperature requirements for that mix (sometimes there is an atmospheric density requirement as well; any density requirement must be met regardless of whether or not a temperature requirement is fulfilled), and a d% die roll result range. If the temperature and density requirements are met, the creator must make the d% roll. If the result of the roll is in the indicated range, the planet's hydrosphere mix is set to the composition indicated by that possibility. A planet meets the temperature requirements if the top of its temperature range is as cold as or colder than the indicated temperature category. Should the top of its temperature range be colder than the indicated temperature category, the indicated mix automatically becomes the mixture used for the planet's hydrosphere, regardless of the result of the d% roll. Some temperature ranges indicate a categorical level "or higher"; in these cases, the temperature requirement is for the indicated category as the bottom of the planet's temperature range, with any higher categories at the bottom automatically fulfilling the requirement (opposite of the way it normally works). If the temperature and/or density requirements are not met or if the d% roll does not come up in the indicated range, the creator will skip that possibility and go to the next one listed. If the creator comes to the last possibility given for a particular atmospheric mix, the mix listed automatically becomes the mixture used for the planet's hydrosphere. Finally, if the planet's atmosphere was tainted due to vulcanism, "Sulfur Compounds" should be tacked on to the planet's hydrospheric composition except in the case where that is already the main hydrospheric component.

Determination of Hydrospheric Mixture using Atmospheric Mix and d% Roll
Atmospheric Mix First Possibility Second Possibility Third Possibility
Requirements d% Result Hydrosphere Requirements d% Result Hydrosphere
Ammonia Arctic 00-66 Liquid Ammonia Ammonia Compounds
Ammonia, Hydrogen Ammonium Hydroxide
Carbon Dioxide Arctic
Thick Atmosphere or Denser
00-21 Carbonic Acid Water
Carbon Dioxide, Water Vapor Carbonated Water
Carbon Monoxide Subarctic 00-46 Liquid Carbon Monoxide None
Chlorine Chlorine Compounds
Chlorine, Carbon Dioxide Arctic
Thick Atmosphere or Denser
00-21 Carbonic Acid Carbon Tetrachloride
Cyanoacetylene Water
Fluorine Subarctic 00-49 Liquid Fluorine None
Fluorine, Carbon Dioxide Subarctic 00-49 Liquid Fluorine None
Fluorine, Chlorine Subarctic 00-49 Liquid Fluorine Arctic 00-65 Liquid Chlorine None
Fluorine, Nitrogen Subarctic 00-44 Liquid Nitrogen Subarctic 45-49 Liquid Fluorine Hydrofluoric Acid
Helium, Sodium Subarctic 00-02 Liquid Helium Searing or Higher 00-06 Liquid Sodium Sodium Compounds
Hydrogen, Helium Subarctic 00-02 Liquid Helium Subarctic 03-11 Liquid Hydrogen None
Methane Subarctic 00-64 Liquid Methane None
Methane, Ammonia Subarctic 00-64 Natural Gas None
Methane, Ammonia, Argon Subarctic 00-64 Natural Gas None
Methane, Ammonia, Hydrogen Subarctic 00-64 Natural Gas None
Methane, Hydrogen Cyanide Subarctic 00-64 Liquid Methane Tropical 00 Hydrocyanic Acid None
Methanol, Ethanol Searing 00-28 Methyl Alcohol Searing 29-55 Ethyl Alcohol Water
Nitrogen Subarctic 00-44 Liquid Nitrogen None
Nitrogen, Carbon Dioxide Subarctic 00-44 Liquid Nitrogen Arctic
Thick Atmosphere or Denser
00-21 Carbonic Acid Water
Nitrogen, Chlorine Arctic or Higher 00-66 Chloramine Hydrochloric Acid
Nitrogen, Oxygen Subarctic 00-44 Liquid Nitrogen Water
Oxygen Subarctic 00-52 Liquid Oxygen None
Oxygen, Carbon Dioxide All Temps 00-49 Carbonated Water Water
Oxygen, Hydrogen Water
Oxygen, Hydrogen Cyanide Tropical 00 Hydrocyanic Acid Water
Oxygen, Water Vapor Water
Sulfane, Sulfur Dioxide, Sulfur Trioxide Arctic 00-39 Liquid Sulfane Sulfur Compounds
Water Vapor Water

Note that it is possible for a planet indicated as a Liquid World to wind up having no hydrosphere (either because it has insufficient gravity to have an atmosphere or as a result of the hydrosphere mixture selection process). When this occurs, the planet needs to be reclassified as a Rock World.

Once the hydrospheric composition has been determined, the planet's hydrospheric coverage (how much of the planet's surface is dominated by its hydrosphere) should also be determined. This is based on a die roll, which itself is determined by the planet's type. For Molten and Frozen Worlds, a d10 roll is made; the result is the planet's hydrospheric coverage. For Rock and Liquid Worlds, a d% roll is made, the result of which is divided by two and rounded down. For Liquid Worlds, fifty is added to this result; no additional amount is added for Rock Worlds. The final result of this calculation is the planet's hydrospheric coverage.

If the planet creator intends for their world to be colonizable, their world's hydrosphere must consist of Water.

Cyvuspe has a Nitrogen, Oxygen Atmosphere with a temperature range of Temperate to Searing. Checking the table for Nitrogen, Oxygen, we see that there are two possible hydrospheric mixes, Liquid Nitrogen or Water. Liquid Nitrogen is the first possibility, so we'll check it first. Its temperature requirement is Subarctic; the high end of Cyvuspe's surface temperature range is Searing. This is well above Subarctic, so we have to skip that first possibility. Water is the next and last possibility for Nitrogen, Oxygen, so that becomes the planet's hydrosphere. Since we're making Cyvuspe an Earth-like world, this is a Good Thing. For hydrospheric coverage, we'll just pick a value similar to Earth's and set it at 80%.

Lolydu has no atmosphere and will therefore have no hydrosphere; we can note this in the planet's stats.

Determine the planet's lithospheric composition.

The composition of the minerals in the planet's lithosphere (the solid outermost shell of a rocky planet) must be determined at this point in the procedure. Its composition determines what elemental materials will be most commonly encountered during exploration on that planet's surface (see Chapter 8.2). Gas Giants have no lithosphere by definition.

To determine a planet's lithospheric composition, a creator needs to select three elements by making three d% rolls and referencing the results on the following table; alternatively, the creator may simply select whatever minerals they wish. The first mineral indicated becomes the primary mineral for the world (i.e. the most common mineral to be found on the planet), the second one becomes the secondary mineral, and the third becomes the tertiary mineral. A single mineral can appear more than once in the listing of a planet's lithospheric composition, though it's not recommended (particularly if the same mineral winds up as both the primary and the tertiary mineral, skipping over the secondary listing).

Minerals
Name of Element d% Roll
Aluminum 00-04
Antimony 05-07
Bismuth 08-10
Borax 11-13
Calcium 14-16
Carbon 17-19
Chromium 20-24
Cobalt 25-27
Copper 28-33
Gold 34-36
Halite 37-42
Iron 43-45
Lead 46-48
Magnesium 49-51
Mercury 52-54
Molybdenum 55-59
Nickel 60-62
Platinum 63-65
Silicon 66-68
Silver 69-73
Strontium 74-76
Sulfur 77-79
Tin 80-82
Titanium 83-85
Tungsten 86-90
Unobtanium 91-93
Uranium 94-96
Zinc 97-99

Planet creators who have some knowledge of chemistry (or who play with other players who do) might realize that certain combinations of lithospheric mineral elements and mixtures in the atmosphere or hydrosphere would simply never occur in real life. It is perfectly acceptable for a creator to make deliberate selections in order to replace any randomly rolled minerals and avoid these situations. The vast majority of players probably won't know enough to notice any problems. Planet creators are welcome to change the "Unobtanium" result into any elemental ore of their liking.

Rain on chemistry; we'll go ahead and pick our minerals for both worlds using d% rolls. For Cyvuspe, the d% results are 98, 01, and 74. This corresponds to a lithosphere of Zinc, Aluminum and Strontium. For Lolydu, the d% results are 86, 17 and 88. This would correspond to Tungsten, Carbon, and Tungsten, but it's not a good idea to have Tungsten twice (particularly since it skips over the secondary mineral spot), so we'll replace the second occurrence. For the heck of it, we'll just pick something on the table rather than re-roll it, and say Uranium. So Lolydu's final lithosphere becomes Titanium, Cobalt and Uranium. It sounds like Lolydu might make a good candidate for a Mining Base; too bad such a base was not generated in the system creation procedure. That could, however, easily be the basis for an adventure or two...

Determine the planet's biodensity and mineralogical density.

At this point in the procedure, there are two vital planetary stats that need to be determined. The first is the planet's mineralogical density, which is simply a measure of how much of the planet's crust contains mineable materials expressed as a percentage. In WCRPG, this value is used to determine whether or not a mineral deposit will be discovered during surface exploration (see Chapter 8.2). A planet's mineralogical density is dependent upon its physical size, its density, and its level of tectonic activity. Gas Giants always have a mineralogical density of 0%, due to the fact that they have no lithosphere.

Cy massdata

Mass, Biodensity and Mineralogical Density.

The second stat is the planet's biodensity (also sometimes called biomass). This is a measure of how much of the planet's non-liquid surface supports higher organisms (anything more complex than a "carpet lifeform" such as grass). Like the mineralogical density stat, this value is expressed as a percentage, and is used during surface exploration to determine whether or not lifeforms will be encountered. A planet's type, tectonic activity level, atmospheric composition, and hydrospheric mixture all serve to help determine its biodensity.

Earlier in the planet creation process, the creator recorded a value for their planet's composite "mineral bonus". To determine the planet's mineralogical density, all that the creator needs to do at this point is to roll d% and add that mineral bonus to the result of the roll. The final result is the planet's mineralogical density. A planet's mineralogical density cannot be less than zero percent; if a lower value results, set the mineralogical density to 1%. Similarly, a planet's mineralogical density cannot be greater than 100%; if a higher value results, set the mineralogical density to 100%.

Biodensity is determined similarly to mineralogical density, though the final die modifier cannot be set until the planet's atmospheric and hydrospheric mixtures are known. To find the modifier, a creator needs to use the table below and reference the row that most closely matches the planet's surface and atmospheric mixture conditions, adding the indicated bonus to any prior bonuses for tectonic activity. Some ecosphere lanes are better than others; a -25 penalty is applied to the final roll for any world in the ecosphere closer than the Tidal Lock Radius. Should the planet's hydrosphere consist of Water, an additional +5 bonus modifier will be added to the final roll. The planet's biodensity will equal the result of a d% roll plus all of the modifiers. A planet's biodensity cannot be less than zero percent; if a lower value results, set the biodensity to 0%. Similarly, a planet's biodensity cannot be greater than 100%; if a higher value results, set the biodensity to 100%. Finally, planets may only contain life if they are a non-Gas Giant located in one of the star's ecosphere lanes; if the planet is a Gas Giant, or if it is not in the system's ecosphere, its biodensity is automatically 0%.

Biodensity Modifier from Planet Type and Atmospheric Composition
Surface Atmosphere Bonus to d% roll
Liquid Nitrogen, Oxygen 15
Liquid Oxygen with Anything Else 10
Liquid No Oxygen -10
Rock Nitrogen, Oxygen -5
Rock Oxygen with Anything Else -10
Rock No Oxygen -30
Frozen Nitrogen, Oxygen -20
Frozen Oxygen with Anything Else -25
Frozen No Oxygen -45
Molten Nitrogen, Oxygen -35
Molten Oxygen with Anything Else -40
Molten No Oxygen -60
Gas Giant Any Atmosphere -200

Earlier in the creation process we recorded a mineral bonus value of -8 for Cyvuspe. That now comes into play. The roll of d% comes up as 13, so the planet's final mineralogical density is 5% (13-8 = 5), which is not all that impressive. Cyvuspe is a Liquid World with a Nitrogen, Oxygen atmosphere. Checking the chart for the biodensity modifiers, we see that this matches the very first row, so the type and atmosphere contribution to the modifier is +15; this is added to the -5 modifier established by the planet's tectonic activity level, for a composite value of +10. Further, since the planet's hydrosphere is made of Water, an additional five points are added to that value, so the total modifier is +15. Finally, we know the world is in the ecosphere beyond the system's Tidal Lock Radius, so this world can have life on its surface and takes no penalties based on its location. The d% roll is made and comes up as 52, so the final biodensity of Cyvuspe is 67% (15 + 52 = 67). Cyvuspe doesn't have a lot of mineralogical value, but it does have some fairly abundant life on its surface (a Good Thing for an Agricultural World).

The recorded value of Lolydu's total mineral bonus was -48. The d% roll for that planet comes up as 41; this would ordinarily indicate a final result of -7%, but since this result is less than zero, the final mineralogical density of Lolydu will be 1% instead. Lolydu is past the Frost Line; this is not in the ecosphere, so the planet cannot have life. For the sake of demonstration, we'll go ahead and figure up what it might've been if it had been in an ecosphere lane. Lolydu has no atmosphere. Its type and atmospheric composition match the "Frozen/No Oxygen row", so their modifier to the biodensity roll will be -45. Since the planet has no hydrosphere, there is no bonus there and the final overall modifier is -60 (counting the -15 previously recorded from tectonics). The d% roll comes up as double zero, which gives a final result of -60% (0 - 60 = -60). Since the biodensity can't be less than zero, this value gets set at zero percent. The planet turns out to be completely lifeless (no surprise there) and it's almost completely worthless as a source of minerals (though someone might still try to get at the minerals it does contain; better still, these conditions make it a nearly perfect choice for an Industrial World).

Determine the severity of the global weather.

The final major planetary stat that needs to be determined is the severity of the global weather. Weather is defined as the set of all the phenomena occurring in a given atmosphere at a given time (by this definition, a planet that has no atmosphere has no weather either). A planet's weather is a very highly complex system, dependent upon a slew of factors (including the amount of incoming solar radiation, surface gravity, rate of rotation, axial tilt, atmospheric mix, hydrospheric mix, geology, and so forth). The mathematics involved in a simple meteorological forecast are well beyond most gamers, to say nothing of what would be required to produce an accurate global weather model. WCRPG takes a bit of a shortcut when it comes to weather by using general weather severity categories instead of trying to generate a precise set of conditions.

For those who are curious: yes, the method for determining weather in WCRPG is based on some real meteorology (the key words there are based on). WCRPG does at least try to emulate the actual severity of the weather based on the planet's conditions. Weather severity in the game is based on the principle of hydrostatic balance, which is a balance between pressure gradient force and other forces within the atmosphere (gravitational force, Coriolis force, centrifugal force, and friction). Pressure gradient force is what produces winds in a planet's atmosphere. As a general rule, the stronger a planet's winds (particularly at its surface), the more severe its weather is. The important terms in the equation for hydrostatic balance are gravity, temperature, a gas constant based on the atmospheric mix, and atmospheric density. The method of accounting for these factors is highly generalized in the game, so planet creators shouldn't have to deal with the inner workings of the math (a Good Thing, as it's a fairly complex differential equation).

To determine the severity of a planet's weather, the creator begins by taking the planet's atmospheric constant (which was determined at the same time as the planet's atmospheric mix) and multiplying it by the atmospheric density weather factor. The creator then takes the planet's gravity, rounds it down to the next whole number, and adds that to the previous result. The planet's temperature weather factor is then added to that result; the final sum of this calculation is the planet's weather intensity index.

At this point, the creator will make a roll of 2d10 for random factors. If the result of the roll is zero, then the creator will add five points to the intensity index and lower the planet's biodensity by 5% (if possible). If the result of the roll is eighteen, the creator will subtract five points from the intensity index. On any other roll, nothing happens. Once any final adjustments to the intensity index have been made, the creator needs only to look up the final value in the table below to determine the proper global weather category.

Categorical Planetary Weather based on Weather Intensity Index Value
Weather Intensity Index Value Planetary Weather Category
<5 None
5-9 Calm
10-14 Moderate
15-19 Violent
>19 Very Violent

Explicitly, the formula for determining the weather severity index is as follows:

(atmospheric constant * atmospheric density weather factor) + gravity (rounded down) + temperature weather factor + unusual conditions modifier = weather intensity index.

Gas Giants have incredibly turbulent atmospheres. If the planet is a Gas Giant and the resultant weather intensity index is 14 or less, the planet's categorical weather severity should be set to Violent; if it is 15 or higher, it should be set to Very Violent instead.

If a planet creator intends for their world to be colonizable the planet's categorical weather severity may not be any higher than the Moderate Category (i.e. the planet's weather may not be Violent or Very Violent).

Cyvuspe has a Moderate atmospheric density (with a weather factor of three), a Nitrogen/Oxygen atmosphere (which has an atmospheric constant of 2), surface gravity of 0.9 gees, and a global temperature range of Temperate to Searing (which has a weather factor of 2). We begin by multiplying the atmospheric constant by the atmospheric density weather factor; we have six so far (2*3 = 6). We then add to that the surface gravity rounded down to the next whole gee; this is zero in this case (0.9 rounds down to zero), so the index remains six. We then add in the temperature weather factor of two; the index is now eight (6+2 = 8). Finally, we roll 2d10; the result of the roll is an eleven, so nothing is added or subtracted from the index value. The final weather intensity index value is eight. Checking the table, we see that this corresponds to a category of Calm; Cyvuspe will therefore have Calm global weather.

Lolydu has no atmosphere (a factor of zero), a gravity of 0.03 G, and a temperature range of Subarctic (factor zero). The final weather intensity index value is obviously going to be zero, which corresponds to no weather (what one would expect for a world with no atmosphere).

Determine the length of the planet's day and year.

The next step in the procedure is to determine the planet's period of rotation and revolution, or the length of its day and its year. These are mainly flavor statistics, though they could potentially be critical pieces of information in an adventure set on the world.

Cy otherdata

Some supplementary "flavor" info.

Calculating the length of a planet's year is somewhat easy, though using a calculator is recommended. All that's needed is the planet's orbital radius and the mass of its primary (or the combined masses of the stars in a multi-star system). The length of the world's year is the square root of the quantity equal to the cube of the orbital radius divided by the primary's mass:

Year (in earth years) = (R3/M)(1/2), where R is the orbital radius (in AU) and M is the primary's mass (in solar masses).

The formula is slightly adjusted for moons:

Lunar orbital period (in earth days) = .0588*((R/12,742)3/M)(1/2), where R is the orbital radius (in kilometers) and M is the mass of the primary world (in Earth masses).

Determining the length of a world's day is more complicated, though it may be based on the length of the world's year. If a world is in tidal lock around its primary, then the period of its day equals that of its year (by definition). A planet in resonance (whether by design or as indicated as a result of the procedure in Chapter 10.2.3) will have a simple mathematical relationship between its day and its year. To determine the length of day for a world in resonance, the creator will roll 1d10 and find the corresponding result on the table below.

Length of Day for Worlds in Spin-Orbit Resonance by d10 Roll.
d10 Result The Length of the World's Day is...
0 ...two-thirds the length of its year.
1 ...60% the length of its year.
2 ...one-third the length of its year.
3 ...half the length of its year.
4 ...40% the length of its year.
5 ...1.5 times the length of its year.
6 ...one and one-third times the length of its year.
7 ...three times the length of its year.
8 ...2.5 times the length of its year.
9 ...twice the length of its year.

For all other planets, the length of the day may either be selected arbitrarily or determined by the result of a 2d10 roll. A value equal to thirty-three minus the planet's Size Class will be added to the result; the final result is the base number of Earth hours in the planet's day. If the result is 36 hours or later, or if the unmodified result of the die roll was sixteen or higher, a 1d10 roll must follow to determine if unusual circumstances exist. If the result of the 1d10 roll is five or less, the initial result stands without further modification. Otherwise, a final 1d5 roll is made, the result of which is multiplied by a factor that is dependent upon the result of the previous 1d10 roll; the resultant value is added to the previously determined length of day as a number of additional hours. The multiplier to be used in a given situation may be found on the following table:

Length of Day Multiplier based on a Higher-End Result of a d10 roll.
d10 Result 1d5 Multiplier
6 48 hours
7 240 hours
8 480 hours
9 2400 hours

If the final number of hours indicated in the planet's day is greater than or equal to its period of revolution, it will be in tidal lock regardless of any other factor.

Finally, there is the possibility that a planet will have a retrograde rotation about its axis (which simply means that its direction of rotation is opposite that of the world's primary). Retrograde rotations will have no in-game effect; they are simply another piece of "flavor" information a creator may wish to add to their planet. To determine if retrograde rotation exists for a planet, the creator will roll d%. If the world in question is not a moon, a result of 74 or higher indicates a retrograde rotation. If it is a moon, a natural 99 is required.

Cyvuspe is orbiting its system's barycenter at a distance of 1.009 AU. The mass of the system's primary is 1.02 Solar Masses and its companion's mass is .48 Solar Masses; this gives a combined mass of 1.5 Solar Masses. We simply plug this data into the equation for the planet's year: Cyvuspe has an orbital period of .828 Earth Years ((1.0093/1.5)(1/2) = (1.027/1.5)(1/2) = 0.684(1/2) = 0.828), about 302 Earth Days or so. We could easily set the length of Cyvuspe's day equal to that of the Earth, but let's have some fun and let the dice decide for us this time around. Cyvuspe is a PSC18 planet, so we'll tack on fifteen (33-18 = 15) to the end of a 2d10 roll. The dice are cast and total five; Cyvuspe has a rotational period of twenty Hours (5+15 = 20). So both the planet's day and year are shorter than that of Earth.

We haven't got any data on Nycalca, the Gas Giant around which Lolydu orbits, so we're in a position where we have to make up a few values arbitrarily if we're going to determine Lolydu's year. We'll just pick a few values: Nycalca will be a PSC 27 Gas Giant with a density of 0.15 Earth Densities; this will give it a mass of 47.99 Earth Masses. Lolydu orbits the planet at a distance of 218,257.78 kilometers. That's enough information to proceed. Since we're dealing with a planet-moon system here, we'll use the formula for lunar orbital period and just plug in our values. Lolydu completes an orbit around Nycalca once every 14.4 Earth Hours (.0588*((218,257.78/12,742)3/47.99)(1/2) = 0.6017, 0.6017 * 24 = 14.4). We know that the moon is in tidal lock, so its day will equal its year; its rotational period will also be 14.4 Earth Hours.

Determine the planet's value as a colonizable world.

While finding and colonizing colony worlds was never the focus of any piece of Wing Commander canon, there can be no doubt that both of the major powers (the Terran Confederation and the Kilrathi Empire) established colonies throughout their territory, some of which are mentioned explicitly throughout the series. It was even established in Privateer that the Confederation had an Exploratory Service, part of whose job no doubt entailed finding suitable sites to put down new Confederation colonies. Colony recommendations may therefore serve as a source of revenue for characters who go exploring frequently. The next step in the planet creation process is to determine how valuable the planet will be should a character group ever submit a colony recommendation for it.

In order for a planet to be eligible to become a potential colony world, it must meet the following criteria:

  • The planet must have an atmosphere and that atmosphere must contain Oxygen. It doesn't matter what other gases are in the mix (so a planet with an atmosphere of Oxygen, Hydrogen Cyanide does meet this criterion). The atmospheric density also does not matter (though colonists will probably be hesitant to head to a world where the atmosphere is not dense enough to breathe).
  • The planet must have a hydrosphere and that hydrosphere must contain Water.
  • The planet's categorical surface temperature range must contain the Temperate category and/or the Tropical category. Note that the other temperature categories may be present; it only matters that at least one of these two are present.
  • The planet's categorical vulcanism or seismicity may not be Heavy or Extreme, and its global weather severity may not be Violent or Very Violent; all other categories for these phenomena are acceptable.
  • The planet's surface gravity must not be higher than two gees. Planets with gravitational pulls of 0.8 to 1.2 gees are considered optimal worlds, which potentially have a higher monetary value.
  • The planet may not already be inhabited or have already been recommended for colonization by the character group making the recommendation.

Any planet that does not meet all of these criteria cannot be colonized and has a recommendation value of zero. Note that this does not automatically remove the planet from consideration for other purposes, such as becoming a homeworld (Kilrah is a good example; it obviously has Extreme vulcanism from what you see of it in Wing Commander III, and its seismicity was high enough that a Temblor bomb could shake the whole planet apart).

Should a planet meet all of the criteria necessary to be considered as a colony world and its designer does not intend to make it already inhabited by anyone, it must be assigned a monetary value. To do this, the creator will roll 1d10 to set a base monetary value. On a roll of four or less, the planet's base value is ¤30,000; five to seven indicate a base value of ¤35,000, while eight or nine indicate a base value of ¤40,000. ¤5000 should also be added to the base value if the planet has optimal surface gravity. After making any adjustments for abundant life and/or optimal surface gravity, the final amount indicated is the planet's value. This value should be placed somewhere in its notes (it's alright to place the value in the "Community Notes" section of the Planet Record Sheet, as the planet should not have any communities on its surface at this point).

If a planet does not meet all of the criteria but is recommended anyway, the recommending crew will face a fine. To calculate the fine, the GM will need to multiply the number of times the crew has botched a recommendation times ¤1000, and add to that ¤5000 times the number of criteria that the recommended planet fails to match. The final result is the total fine levied. GMs may elect to only issue a warning rather than a fine the first time a crew botches it, if they're feeling merciful. If not...

Cyvuspe is already inhabited (otherwise it couldn't be an Agricultural World), but for the sake of example let's go ahead and figure up its value as though it were uninhabited. It has a Nitrogen/Oxygen atmosphere, Water hydrosphere, Temperate to Searing temperature range (it contains both the Temperate and Tropical categories), and Calm Vulcanism, Seismicity and Weather, all of which match colonization criteria. With a gravity of 0.9 gees, Cyvuspe is not only a habitable world, it is optimal. The d10 roll comes up as an eight; the base value is going to be ¤40,000. ¤5000 is added due to it being an optimal world. The 72% biodensity is just slightly too low for it to gain an additional bonus, so Cyvuspe's final value is ¤45,000, a pretty good catch. Too bad the world is already inhabited. At least the fine for recommending it would be a minimal ¤5000.

Lolydu is obviously not a colonizable planet. However, the base value of a fine can readily be determined for it in the event that someone out there is dumb enough to recommend it. It has no atmosphere, so that adds ¤5000 to the fine. It also has no hydrosphere; another ¤5000 is added to the fine. Since it contains neither the Temperate nor the Tropical temperature categories, another ¤5000 will be added. Lolydu has no weather or tectonic activity and its surface gravity is below two gees; those criteria match. So, ¤15,000 would be the base value of the fine in the event that somebody ever recommends Lolydu as a colony site (which is not too bad, all things considered).

Determine the planetary geography (if necessary).

With the completion of the planet's monetary value calculation, its basic statistics are complete. If the planet is just being used as a backdrop for an adventure, the creator need not do anything else at this point. However, if the planet is to be the centerpiece of an adventure, the creator probably should take the time to complete the final few optional steps of the procedure. Creators may complete these steps even if the information isn't critical for an adventure if they so desire.

All planets in WCRPG use Mercator projections (more commonly just called Mercators) to illustrate their surface features. A Mercator is a cylindrical map projection commonly used because of its ability to represent lines of constant course as straight segments. There is some distortion with Mercator projections (particularly around the poles), but they are far easier to create and use than most other cartographic methods (more importantly, they allow surface navigation to take place on an orthogonal grid). Creation of a Mercator may or not be required when it comes to the planet creation process. If there's a chance that a character group will visit a given world, it behooves its creator to go ahead and map out its surface. If the creator wants to leave the geography up to an adventure's GM, they are certainly welcome to do so.

While there is no "correct" way to build a planetary Mercator, there are some things that a creator may do that will make the overall layout of their planet more logical and natural-looking. Planetary type is perhaps the best predictor of what's appropriate for a planet’s surface geography, but other stats may come into play as well (the global surface temperature range, for instance, may help determine whether it's more appropriate for an icepack or a desert to be located at the poles). What follows are some general recommendations that will suit most situations. Creators are welcome to follow these recommendations or ignore them at their own discretion.

Mercators are generally not necessary for Gas Giants. Since a Gas Giant has no solid surface, there isn't much of a surface to plot. Their atmosphere consists of turbulent gases flowing at significant speeds, creating an ever-changing "landscape" that's almost impossible to map. That's not to say that a creator can't make a Mercator for a Gas Giant, but since it's obsolete the instant it's finished (and since surface navigation is impossible anyway), there's very little point in making one. For those that insist on making Mercators for these worlds, creators should consider mapping the location of any significant, long-lasting atmospheric storm systems, such as Jupiter's Great Red Spot or Saturn's north polar hexagon.

A creator should definitely consider their planet's level of tectonic activity, and vulcanism in particular. Volcanoes play a big part of shaping a planet's surface by smoothing over areas that have been impacted by cosmic collisions (asteroids, comets and the like) with lava flows and/or volcanic ash. Rocky planets that have no vulcanism will acquire over time what's known as an "old" surface, which simply means that it's pockmarked with craters. Planets with old surfaces tend to have large shifts in elevation; their terrain is not very smooth. When active volcanoes are present, a planet will have a smoother surface (what's known as a "young" surface; shifts in elevation won't be as drastic). Earthquakes also play a part in shaping a planet's surface; the more prevalent earthquakes are, the more mountainous the terrain will tend to be on a global scale. Planets with significant weather also tend to have younger surfaces than those with little to no weather. Interactions between vulcanism, seismicity and weather severity have a lot of bearing on a planet's landscape. For instance, a combination of severe planetary weather, weak global seismicity and no vulcanism will lend itself to a barren landscape, where the wind and rain have scoured the land clean of any features.

For the sake of simplicity, planetary surface features in WCRPG are indicated through changes in the elevation of the planet's terrain. Each planet type in the game has its own color scale with anywhere from six to eight "levels", which can be viewed alongside the planet's Mercator. The highest planetary elevations correspond to the color at the physical top of the scale, while the lowest elevations (corresponding to oceans, inland seas, icepack, lava seas, or just lower-lying terrain) are always at the bottom. Images of these color scales are available in the table below.

Elevation Color Scales by World Type
Frozen Gas Molten Rock life Rock non
Frozen Gas Giant Molten Liquid / Rock
(Life Bearing)
Liquid / Rock
(Non-Life Bearing)

To create their planet's overall terrain, creators should begin by drawing out the lowest elevation. This has the effect of denoting which areas are "continental" and which ones are "maritime" (creators are reminded that habitable Rock Worlds can have seas of water, it's just that they will take up less than half of the planet's surface). On the "land" areas, the creator can then add the next highest level of elevation and continue to add higher levels until they either reach the top of their scale or are satisfied with the overall terrain. By using this "bottom up" technique, creators can easily define the locations of major bodies of water as well as significant mountain ranges. From those features, the locations of glaciers, forests, jungles and deserts can be determined, which helps to set the planetary ecology. Alternatively, a creator can start at the top and work their way down; this "top down" technique works well for Frozen and Molten worlds. Creators should be careful if going "top down" if they are making a Liquid or Rock World, since they might accidentally create the wrong type (i.e. have too much water for a Rock World or too little for a Liquid World).

All planet types will tend to be shaped by the placement of continents (particularly the placement of mountain ranges) and the planet's surface temperature range. Any oceanic regions will tend to be frozen into icepacks if the local temperature is in the Arctic category or colder; these areas will generally be near the planet's poles. Land regions in the same areas may be covered in glaciers or fjords. Temperate and Tropical regions may play host to all kinds of forested areas, though usually these will be more common on the "windward" side of any mountain ranges that lay perpendicular to the direction of the prevailing winds (which is usually the direction of the planet's rotation along its axis; winds in the middle latitudes blow in the same direction, while those in the higher and lower latitudes tend to blow in the opposite direction). Open plains and plateaus may also be found in these same areas. Desert regions may be found on the leeward side of mountain ranges or in areas where the local temperature is in the Searing category or hotter. Desert regions are also common within the 28-32° latitude regions (this has to do with the mechanics of atmospheric transport; on Earth, it explains the presence of major deserts such as the Mojave, the Sahara and the Australian Outback). Other features such as inland rivers, plains, plateaus, canyons, and cave systems may be added after these major features have been set. Planets built using these general guidelines will have a number of terrain types that mimic realistic planetary geological and meteorological interactions.

Since the design of a Mercator is something that happens based on the whims of a planet's creator, the examples in this section are going to illustrate some different design philosophies rather than specific examples. We won't be indicating specific features (deserts, forests, etc.) for these two worlds to keep things simple.

For Cyvuspe, we're going to use the planet's grid-lines to set areal limits on the terrain (which is a perfectly valid way of creating a Mercator map though the final result is going to look heavily "pixelated"). We're gunning for a Liquid world with 80% hydrospheric coverage, which means most of the terrain is going to need to be ocean. We'll set one large island-like continent in the northern/eastern hemisphere, with a long, narrow, low-lying land mass in the western hemisphere. We'll go ahead and use the Liquid life-bearing elevation scale for the terrain, using a digital version of the Planet Reference Sheet and MS Paint to fill in the Mercator. The final result looks something like this:

Cy mercator

This map uses the planet's grid-lines to delineate the terrain.

For Lolydu, we're going to ignore the grid lines and just let the terrain flow from one block to the next. We'll make the terrain mostly steppe plateau, with some mountainous terrain in the northern/western hemispheres and a southern continental "sea" of smooth low-level terrain. We'll use the Frozen elevation scale as it appeared earlier for this world (at least, as close as we can get to it using colored pencils...).

Lolydu mercator

For this Mercator, the designer elected to use a more "natural approach".


Create lifeform lists for the planet (if necessary).

The presence of life on a planet's surface adds another level of complexity, as life indicates the presence of a biosphere, a global ecological system integrating all living beings and their relationships, including their interaction with the elements of the lithosphere, hydrosphere, and atmosphere. Given everything that goes into them, it goes without saying that ecospheres are fabulously complex systems.

To try and keep things relatively simple, WCRPG bases planetary biospheres only on the presence of significant lifeforms, which are lifeforms that are generally important enough to have monetary value or dangerous enough to be noteworthy. Though there may be a number of lesser lifeforms on a planet's surface, they are ignored in favor of the largest and most valuable lifeforms on the planet; these are known as megaflora (large producers) and megafauna (large consumers). Planets may or may not have an explicit listing of which significant lifeforms are present on their system, what's known as a lifeform list in WCRPG.

If a planet has a biodensity rating greater than 0%, its creator will need to decide whether or not they wish to make an explicit lifeform list for it. It is acceptable for a creator to not create a lifeform list; this will transfer the responsibility for generating the list to the GM of any adventure in which the planet is featured. It gives the GM more latitude to be flexible and opens the world up for them to create their own lifeforms. Creating an explicit list, on the other hand, saves the GM from having to do all of the work involved in creating a lifeform list on their own (which can be considerable, particularly since no matter who does the work it is possible that some of the lifeforms will have to be made from scratch).

Cy lifeforms

A sample lifeform list.

Creating a lifeform list is not difficult. First, a creator must decide how many significant species exist on the surface of their planet. The planetary exploration rules listed in Chapter 8.2 set a maximum limit of nine significant lifeforms on a planet's surface, so the creator may choose anywhere from one to nine different species. If they would like to select a number at random, they may make a 1d10 roll, with the result indicating the number of species present (roll again if a zero is the result).

With the number of significant species selected, the creator must decide which ones will be on the planet's surface. This boils down to one of three options: they may select a list made up of the lifeforms present in the Bestiary, they may use the creature creation rules outlined in Chapter 10.2.7 to create their own custom lifeforms, or they may use some combination of the two. Creators are welcome to select whatever lifeforms they desire for their world without consideration of the lifeform's niche; it's assumed that there are sufficient numbers of "insignificant lifeforms" to sustain the selected species, which players will not (necessarily) encounter in their adventures.

Lolydu has a 0% biodensity. Thus, it has no lifeforms of any significance and does not need a lifeform list. Cyvuspe has a 72% biodensity, so we can go ahead and create a list for it. To save time, we'll just use the "other worlds" lifeform list from the Bestiary and we'll let the dice determine how many significant lifeforms will be present in the planet's biosphere. We begin by rolling 1d10; the result is zero, so we'll roll again. A four is the result of the second attempt, so we'll place four significant lifeforms on the planet. We simply select four lifeforms off the list: the megafauna on Cyvuspe will consist of Bugbears, Centaurian Mud Pigs, Dioscurian Ovizards, and Gnuflies.

Create a number of communities for the planet (if necessary).

Once a planet’s geography is determined, a number of communities may be created on its surface using the procedure outlined in Chapter 10.2.5. Communities on a planet's surface are always optional and a perfectly inhabitable planet may be left completely empty if that is the creator's desire. A creator who wishes to put down communities should consider the planet's level of habitability when answering the question of how many communities to establish on the surface of their world.

A planet doesn't need any communities if it is uninhabitable (if it has no Oxygen in the atmosphere and/or no Water in the hydrosphere). If a creator does decide to set a few on that world, they should be limited to no larger than Village size and the number of communities should be severely limited (perhaps no more than half a dozen or so for the entire planet). Since the planet itself cannot sustain life on its own, communities on its surface must either produce or be supplied with what they need for their continued existence. Part of the makeup of these communities must therefore include objects and items necessary for the continued survival of the inhabitants (such as pressure domes, humidity windtraps and collectors, large oxygen or water tanks, and so forth). GMs may decide to make critical supply shortages or equipment malfunctions in these communities the focus of an adventure.

Cy towns l-points

Community data for a habitable world.


A planet that has Oxygen in the atmosphere and Water in the hydrosphere, but has something else out of whack (temperature too hot or too cold, gravity higher than two gees, violent weather or tectonic activity, etc.) may have more communities on them than uninhabitable worlds, but these communities will still likely be small and relatively dispersed. Communities on these worlds may or may not have some kind of system in place to combat the adverse conditions (such as covered heated or air-conditioned passages with airlock-style entrance points, extra strong construction, full-on pressure domes, etc.). They are liable to not be as restricted as communities on uninhabitable worlds, though they still won't offer the total freedom of planets on more habitable spheres. It is recommended that this kind of planet have no more than 1d5 communities of Village or Small Town size at maximum, with a progressive double or triple the number of smaller communities (for example, this kind of planet might have 2 Small Towns, 4-6 Villages, 8-18 Rural Villages, and 16-54 Settlements).

Planets that are completely habitable have no restrictions on the number of communities that may exist on their surfaces. These are your run of the mill communities; usually any external coverings or supplies they have in them are strictly for emergency and/or defensive purposes (and the vast majority of these communities will forgo having defensive supplies altogether, particularly in more advanced societies). For these planets, 3d5 communities of Small Town or Large Town size is recommended, with a progressive double or triple the number of smaller communities and a progressive half or third (round down) the number of larger communities. For planets with optimal gravity, this can be changed to a base of 3d5 communities of Large Town or Small City size. The community types and die rolls recommended are for fully inhabited planets and a creator should feel free to create fewer or smaller communities for it if it would better fit the campaign for which the world is intended. Creators may also simply not feel like creating that many communities for their world; this is perfectly acceptable.

When the number of communities on a world has been determined, they should be placed on the planet's Mercator map (provided one has been created). Ideally, communities should be placed close to sources of food, water, and natural resources if possible. If a community is particularly ancient, it may be built on or near a feature such as a hill or plateau (which would have helped to defend the original settlement). Communities can be anywhere, but a creator would do well to remember that there is a reason why communities originate in the first place and give them some logical placement.

If the creator is a glutton for punishment or simply wants to be really thorough, they can proceed with filling in the details of any communities they create. The information in Chapter 10.2.5 can get a creator started with filling in those details, but they by no means have to stop there. Such information as the planetary gross domestic product, total population and predominant power structures on the planet's surface may also be filled in. It’s recommended that the creator have a campaign in mind if they go to this amount of trouble for their world.

Once any communities have been created, the planet itself is ready to be used. If the creator desires, additional details may be added to its description (such as locations of archaeological dig sites or ruins, the names of the major oceans, the color of the sky, and so forth). These details may be used to help "flesh out" a world and serve to make it a more vibrant, living place.

Cyvuspe is an inhabited Agricultural World, so let's muck up its fertile plains a bit by throwing down some communities on its surface. The roll of 3d5 comes up as an eleven; we'll need to put 11 Large Towns on the planet's surface. From that number, we know we'll need anywhere from 22-33 Small Towns, 44-99 Villages, 88-297 Rural Villages, and 176-891 Settlements. As far as larger communities go, there could be anywhere from three to five Small Cities, one or two Large Cities, and maybe a Metropolis. Even going with the minimum numbers, the planet will need at least 345 communities, meaning we've got a lot more work ahead. Perhaps we'll leave that work up to a GM. Better still, we could just change our minds entirely and make the planet uninhabited instead...

Lolydu qualifies as an uninhabitable planet since it has neither an atmosphere nor a hydrosphere. We don't need any communities on its surface, but for the heck of it let's put down a Rural Village (it would make sense if someone was out there trying to set up shop for heavy industry, especially since there's no environment to destroy). It would probably have to have a pressure dome to trap an atmosphere as well as a waste and water treatment facility to keep the place supplied with potable water. Hydroponic facilities could be used to grow food; it's conceivable that this community would become self-sufficient, provided a sufficient store of backup parts for all the necessary equipment was kept on site. Better yet, if the citizens of Cyvuspe could be convinced to set up a trade route, food and water from Cyvuspe could be traded to the residents of the Lolydu settlement in exchange for finished products. Now, how to set up such a trade route, and how to keep it safe from anyone who might want to disrupt it, such as a local pirate clan...

Locate the world's Lagrange Points (if necessary).

If a planet creator has built their world as a continuation of the star system creation process, a final step they may wish to perform is the determination of the exact positions of the Lagrange points associated their world. Usually this will be done as a means of determining the distance to any jump points located in relation to their world, but it may also be done in those cases where some kind of permanent orbital station - a Mining Base, for example - is to be placed at or nearby one of the planet's Lagrange points. Determining the positions of Lagrange points is not all that tricky, though it does require knowledge of the masses of the bodies involved (hence the position of this step at the end of the world creation procedure).

WCRPG makes the general assumption of the "two-body problem" when determining the position of Lagrange points; this is the most basic form of the Lagrangian point formulation. Star systems will contain more than two bodies in most cases, which would ordinarily vastly complicate the problem of determining exactly where the necessary force balances exist (on account of the gravitational attraction of all the other gravitationally significant bodies within the system. The assumption of the two-body problem simplifies calculation, but once again it is not entirely physically realistic. Those system creators with a bent towards realism are welcome to do the necessary math and determine positions and/or the existence of Lagrange Points as they'd actually be. Those who have the necessary data to complete the formulas for Lagrange Point positions but who don't want to do the actual math will find an excellent calculation routine online at http://orbitsimulator.com/formulas/LagrangePointFinder.html.

The only pieces of information needed to solve the Lagrange Point formulas are the mass of the primary body (the combined masses of the stellar objects in a solar system or the mass of the planet around which a moon is orbiting), the mass of the companion body (said planet or moon being created), and the distance between the primary and the companion. Most of this data should've been determined during the star system and planet creation procedures; if not, the planet creator should generate whatever pieces of data they are missing either by going through the procedures or just setting arbitrary values.

To find the position of the Lagrange Points associated with a planet, its designer should first divide the mass of their world by the sum of the masses of their world and its primary. Should the primary body be a star or solar barycenter, the mass of their world should first be multiplied by a factor of 0.000003; otherwise it should be left alone. The resultant value should then be divided by three, and the cubed root of the resulting value should be determined. This value is subtracted from one and then multiplied by the distance between the primary body and the companion body. The resultant value is the distance (in AUs) of the L1 Lagrange Point from the primary.  Simply subtract this value from the total distance between the primary and its companion in order to determine its distance from the companion (i.e. the planet). World creators may multiply the resultant value by 150,000,000 to convert the distance into kilometers.

More explicitly, the formulas for determining the position of the L1 Lagrange Point are as follows:

α = M2 / (M1 + M2), where M2 is the companion's mass and M1 is the primary's mass.
0.000003 Earth Masses = 1 Solar Mass
L1 = R (1-((α/3)(1/3))), where R is the distance between the primary and the companion.

The L1 Lagrange Point is located along a straight line between the primary and the companion.

Once this distance has been determined, the locations of the L2 and L3 Lagrange Points can be determined easily. They are both located along the same straight line as that used for the determination of L1; L2 is located on the opposite side of the companion at the same distance to L1, while L3 is located at the same distance on the other side of the primary at the same distance as L1 from the primary.

L4 and L5 are the trickiest points to locate mathematically; WCRPG uses a simplified system to locate them. They are the same distance away from the primary as the companion, sixty degrees ahead (for L4) and behind (for L5) the companion along its orbit. This forms a pair of equilateral triangles with the apexes at the primary, the companion, and the two Lagrange Points. Due to the properties associated with equilateral triangles, the distance from either the primary or the companion to either of these Lagrange Points is the same as the distance between the primary and the companion. For navigational purposes in WCRPG, both Lagrange Points are one quadrant ahead and behind of the companion's quadrant along the same orbital lane (for more on quadrants, see Chapter 8.4).

For those who actually want to calculate them, the explicit formulas for determining the positions of the remaining Lagrange Points (L2 through L5) are as follows. Bear in mind that these formulas are on a Cartesian coordinate system with the origin point (0, 0) set at the system's barycenter (i.e. the position of the primary).

L2 = R (1+((α/3)(1/3))), 0
L3 = -R (1+((5/12)*α)), 0
L4 = (R/2)*((M1-M2)/(M1+M2)), ((sqrt3)/2)*R
L5 = (R/2)*((M1-M2)/(M1+M2)), ((sqrt3)/2)*-R

Let's go ahead and determine the position of the Lagrange Points associated with Cyvuspe, since we know there are jump points at the world's L1, L2 and L5 Lagrange points. We know from our earlier calculations that Cyvuspe's mass is 0.624 Earth Masses, that it is located 1.009 AU from the system's barycenter, and that the combined masses of the twin stars of the system add up to 1.64 solar masses. We'll begin by determining the alpha value; we have to convert the planet's mass into Solar Masses, since we're dealing with stellar primaries. The final alpha is 1.141*10-6 ((0.000003*0.624) / (1.64 + (0.000003*0.624)) = (0.000001872 / (1.64 + (0.000003*0.624)) = (0.000001872 / (1.640001872)) = 1.141*10-6). We get a final position of the L1 Lagrange Point at a distance of .007 AU from Cyvuspe, or roughly 1,096,720 kilometers away (1.009 (1-((1.141*10-6/3)(1/3))) = (1.009 * .9927) = 1.002, 1.009 - 1.002 = .007 AU, * 150,000,000 = 1,096,720.19 km). So, we know that L1 is 1,096,720 kilometers away from Cyvuspe directly towards the system's barycenter. We also now know that L2 is the same distance away from Cyvuspe directly away from the system's barycenter. Finally, we know that L3 is 1.002 AU away (1.009-0.007 = 1.002 AU) from the system's barycenter on the opposite side of the barycenter from Cyvuspe (a total distance of 2.011 AU from Cyvuspe along a straight line through the barycenter). L4 is ahead of Cyvuspe in its orbit at a distance of 1.009 AU, and L5 is at the same distance but behind Cyvuspe in its orbit.

For Lolydu, we'll recycle the same values we had to generate for Nycalca when we determined the moon's day and year. Nycalca is a PSC 27 Gas Giant weighing in at 47.99 Earth Masses, and Lolydu orbits it at a distance of 218,257.78 kilometers. We also already know Lolydu's mass is 0.0000975 Earth Masses, so we have all the information we need to proceed with finding Lolydu's Lagrange Points (though there is no real reason to do so, since none of the moon's Lagrange points correspond to any jump points). The alpha value for the Nycalca-Lolydu system will be 2.032*10-6 (0.0000975 / (47.99 + 0.0000975) = 0.0000975/ 47.9900975 = 2.032*10-6). This puts the L1 Lagrange Point at a distance of 1,916.67 kilometers from Lolydu (218,257.78 (1-((2.032*10-6/3)(1/3))) = (218,257.78 * 0.9912) = 216,341.11, 218,257.78 - 216,341.11 = 1,916.67). We know that the Nycalca-Lolydu L1 is 1,916.67 km from Lolydu towards Nycalca, L2 is 1,916.67 km from Lolydu away from Nycala, L3 is 216,339.92 km on the opposite side of Nycalca, L4 is 218,257.78 kilometers ahead of Lolydu in its orbit, and L5 is 218,257.78 kilometers behind Lolydu in its orbit.


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