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10.2.1: Creating Worlds

Table of Contents [Hide/Show] Determine the planet's type and orbital position. Determine the planet's size, mass and gravity. Determine the planet's atmospheric density. Determine the planet's surface temperature range. Determine the planet's atmospheric composition. Determine the planet's hydrospheric composition. Determine the planet's lithospheric composition. Determine the planet's biodensity and mineralogical density. Determine the severity of the global weather. Determine the planet's value as a colonizable world. Determine the planetary geography (if necessary). Create lifeform lists for the planet (if necessary). Create a number of communities for the planet (if necessary).

The worlds of the Starflight Universe are very well defined, at least in terms of general information about each world. This information can be found in the Starflight I Survey and the Starflight II Survey. Because this information is readily available, there will be relatively few occasions wherein it will be absolutely necessary for a whole planet to pop into existence. Occasions that warrant the creation of a new world may include adventures wherein a GM is introducing a new Starfaring Age race or campaigns that take place in brand new Sectors, in which case the GM will likely need to generate world data as part of the creation of new Sectors and star systems (this process is outlined in the next Chapter). The procedure for creating a new planet 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 intraplanetary transits (see Chapter 8.2). The world creation procedure outlined here is designed to allow planets to be created as quickly and as easily as possible without skipping over any of the required data. For purposes of this discussion, all worlds will be called "planets", regardless of whether they are planets or moons. All planets will use the Planet Record Sheet (available in Appendix Two) in order to record their vital stats.

There procedure for creating a new 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 surface temperature range.
5. Determine the planet's atmospheric composition.
6. Determine the planet's hydrospheric composition.
7. Determine the planet's lithospheric composition.
8. Determine the planet's biodensity and mineralogical density.
9. Determine the severity of the global weather.
10. Determine the planet's value as a colonizable world.
11. Determine the planetary geography.
12. Create lifeform lists for the planet (if necessary).
13. Create a number of communities for the planet (if necessary).
    

EDITOR'S NOTE: Planets in the original games weren't exactly physically realistic. This is completely understandable; the designers of Starflight were creating a video game, not a working solar system model. While an attempt has been made to correct some of the more obvious errors with the old planet-building system, planet creators are advised that the planetary creation system outlined below is still largely based on this original system, as the editors of SFRPG are also attempting to create a game rather than a working solar system model. The system as outlined below will enable a creator to build a planet quickly, but will leave out a lot of the details of planetary physics. For those players out there who want to use a more realistic planet building model, there are free-ware programs on the Internet that can create planets with realistic physics. Players with a bent towards realism are more than welcome to use these models, though it will be necessary to redefine some aspects of those models into terms compatible with SFRPG.

Determine the planet's type and orbital position.¶

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

• Liquid planets are planets whose surface is at least half-covered by water or any other liquid compound. 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 are planets that, for whatever reason, have a surface that is at least half-covered with lava flows or molten material. These planets experience extreme vulcanism, usually either due to significant tidal forces upon the planet or close proximity to its primary. They are most commonly found in the orbital lanes immediately preceeding the system's ecosphere.
• Frozen planets are planets that are so cold that whatever water does exist on the planet's surface is most commonly in the form of ice. Frozen worlds are usually lifeless balls of ice usually found in the lanes following the system's ecosphere, though some can be found within the ecosphere and some are capable of supporting life.
• Gas Giants are typically large planets that are primarily composed of large amounts of gases, usually hydrogen and helium. They usually have poorly defined solid or liquid centers. These planets usually have a lot of mass and therefore a lot of gravity. This, combined with the fact that they have no clearly-defined surface, makes a gas giant impossible to land on. The attempt is inevitably lethal for any dumb enough to attempt it.
• Rock planets are any planet with a solid surface that otherwise fails to meet the definition of a liquid, molton or frozen planet. Because of their ambiguous definition, rock worlds have very highly variable conditions. Some may be completely lifeless, with cratered surfaces and no atmosphere. Others may be Earth-like planets in all repsects aside from water content.
  

The planet creator will need to select one of these five types for their world and record the type in the appropriate box on the Planet Record Sheet, as well as the planet's position within the system, if these selections haven't already been made during the star system creation process. The planet's orbital position refers to its place in the system, in this case 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 lanes preceeding the ecosphere (also known as the pre-ecosphere or the innerzone), or the cold orbital lanes following the ecosphere (the post-ecosphere or outerzone). The position of the ecosphere lanes within a star system varies depending upon the effective luminosity class of the system's primary (for more details, see the next Chapter). The planet's position within a star system will set many of its details, such as surface temperature classifications (ultimately determining planetary weather). Using a relative position instead of an absolute lane position allows a designer to simply change the lane of the planet should they wish to place the planet (or a carbon copy of it) around a star of a different luminosity class. Not every planet type can exist in every orbital lane; creators who are making their selections independent of an intended star system should refer to the guidelines in the next Chapter when selecting type and location.

To aid first-time planet designers, two examples will be included at the end of each step in the process. The first example will go through the process of creating an Earth-like planet, while the second one will be a Frozen world. The frozen world will utilize random dice rolls.

Basic Info on the sample frozen planet (note that its
planet number doesn't match its orbit; it can be in the
seventh orbital lane and still be the fourth world).

Let's say our Earth-like planet is exactly like Earth: it orbits in the third lane around a G-type star and its surface is roughly 80% covered with liquid water. Because it's got so much liquid water covering its surface, this world is obviously a Liquid-type planet. We know that it's in the third orbital lane, but position is relative to the system's ecosphere. The chart in Chapter 10.2.2 shows that the ecosphere for a G-type star is between the second and fifth orbital lanes. From this, we can see that for creation purposes the position of the planet is the second ecosphere lane. This knowledge will come in handy later on.

The type of the Frozen world has been set; obviously, we're dealing with a Frozen-type world. The chart in the next chapter shows that frozen worlds are possibilities in the ecosphere through the outer lane of the system. For the sake of this example, we'll put the planet in the second post-ecosphere lane. If both planets are orbiting the same G-type star, this would correspond to the seventh orbital lane. Of course, we could stick the planet around another star just as easily; if the world orbits an M-type star, this would be the fifth orbital lane. Around an O-type star, this would be the tenth orbital lane.

Determine the planet's size, mass and gravity.¶

With the planet's type and position located, the planet's size should be the next thing to be determined. The planet's size will help the designer determine the planet's mass and its gravity. While the planet's mass is largely cosmetic in SFRPG, gravity directly affects a planet's atmospheric density, as well as the severity of the planet's weather.

Planets are massive objects that use their own Size Class scale (though this scale is merely a continuation of the starship Size Class scale (see Chapter 7.2), with starship Size Class 50 corresponding exactly to planet Size Class 0). The range of possible sizes for a planet depends largely on the type of planet indicated 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 type of planet other than a Gas Giant (Liquid, Frozen, Molten or Rock). Of these classes, planets can either be terrestrial worlds (main planets within an orbital lane), dwarf planets (a planet that has not cleared its neighbouring 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 so long as it is at least as large as the minimum required size for the 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 its volume. Aside from affecting the planet's mass and gravity, its density will help to determine its overall mineralogical content, so it's still an important measure even though it's not one of the required statistics for a planet. Planetary densities are usually measured as a multiplier of "Earth Densities", which equals the density of the Earth (5,515 kg/m³ for the curious). As a general rule, objects are denser the closer they are located 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 can roll 1d10 and compare it to the orbital lane of the planet in question; if the result of the roll is less than the value of the orbital lane, the planet is a dwarf planet. Otherwise, it's a normal terrestrial world. A similar procedure can be used to determine moons versus moonlets; a roll result less than the value of the planetary orbital lane indicates a moon. Dwarf planets should be accompanied by a dust belt or 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.

3+1d10
(23-32)

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	2
0.05+(1d10*0.05) (0.05-0.5)

With a size and density value for their planet, the creator has the information they need in order to determine the planet's mass and gravity. All that's needed is to find the planet's size class on the table below. The creator simply needs to read across the row in order to find base values for the planet's mass and gravity, multiply those results by the planet's density value, and record the final result in the appropriate boxes on the Planet Record Sheet. Additionally, each size class has a "mineral bonus" associated with it, which may be used to help determine the planet's mineralogical density later in the procedure. This value 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 also includes a listing of objects in Earth's solar system that fall within various size classes.

.67x10²⁷

SFRPG Planet Size Class Conversion Chart

Size Class	Bounding Box Volume (m3)	Mass (kg) (Earth Density)	Gravity (gees) (Earth Density)	Mineral Bonus	Example
0	2.58x1015	1.42x1019	0.01	-20	Himalia
1	5.15x1015	2.84x1019	0.02	-19	Phoebe
2	1.03x1016	5.68x1019	0.02	-19
3	2.06x1016	1.14x1020	0.03	-19	Mimas
4	4.12x1016	2.27x1020	0.03	-19	Enceladus
5	8.25x1016	4.55x1020	0.04	-19
6	1.65x1017	9.10x1020	0.05	-18
7	3.30x1017	1.82x1021	0.07	-18	Tethys
8	6.60x1017	3.64x1021	0.08	-17	Dione
9	1.32x1018	7.28x1021	0.11	-17	Rhea
10	2.64x1018	1.46x1022	0.13	-16	Io
11	5.28x1018	2.91x1022	0.17	-15	Triton
12	1.06x1019	5.82x1022	0.21	-13	Europa
13	2.11x1019	1.16x1023	0.27	-11	Luna
14	4.22x1019	2.33x1023	0.34	-9	Mercury
15	8.44x1019	4.66x1023	0.43	-6	Mars
16	1.69x1020	9.31x1023	0.54	-3
17	3.38x1020	1.86x1024	0.68	2
18	6.76x1020	3.73x1024	0.86	7	Earth
19	1.35x1021	7.45x1024	1.08	14
20	2.70x1021	1.49x1025	1.36	23
21	5.40x1021	2.98x1025	1.71	34
22	1.08x1022	5.96x1025	2.16	49
23	2.16x1022	1.19x1026	2.72	N/A
24	4.32x1022	2.38x1026	3.42	N/A	Uranus
25	8.65x1022	4.77x1026	4.31	N/A
26	1.73x1023	9.54x1026	5.43	N/A
27	3.46x1023	1.91x1027	6.84	N/A
28	6.92x1023	3.82x1027	8.62	N/A	Saturn
29	1.38x1024	7.63x1027	10.87	N/A	Jupiter
30	2.77x1024	1.53x1028	13.69	N/A
31	5.53x1024	3.05x1028	17.25	N/A
32	1.11x1025	6.10x1028	21.73	N/A
33	2.21x1025	1.22x1029	27.38	N/A	Proxima Centauri
34	4.43x1025	2.44x1029	34.49	N/A
35	8.85x1025	4.88x1029	43.46	N/A
36	1.77x1026	9.77x1029	54.76	N/A
37	3.54x1026	1.95x1030	68.99	N/A
38	7.08x1026	3.91x1030	86.92	N/A	Sol
39	1.42x1027	7.81x1030	109.51	N/A
40	2.83x1027	1.56x1031	137.98	N/A
41	5
3.13x1031	173.84	N/A	Zeta Ophiuchi

Note that this procedure will produce a planet that has reasonable mass and gravity for the minimum volume for a planet of its Size Class. It may be that a creator wants to create a planet with a slightly larger volume within the Size Class, they may do so. The creator will need to use the following formulae (solving them in the order presented) to find the planet's gravity and mass in this case:




The mass formula should be rounded to two decimal places, while gravity should be rounded to one decimal place.

If the planet creator is attempting to build a colonizable planet (more on this below), their world must have a gravitational pull of no greater than two gees. For the world to make an optimal colony, the gravity should be between 0.8 and 1.2 gees.

Once again, we'll say that our Earth-like planet is similar to Earth. Checking the size class table above, we see that Earth is a planetary Size Class 18 (PSC 18) object, so we'll use that as the size of our Earth-like world. We'll also assume Earth's density, so we can just use the values straight from the table. Our planet has a mass of 3.73x10²⁴ kilograms, and a gravity of 0.9 gees (remember that this has to be rounded to one decimal place). That's a little lower than Earth's values, but still well acceptable for an Earth-like planet. Any fitness gurus that live there might like the fact that they'll weigh a little less...

The indicated mineral bonus for the Earth-like world is seven according to the chart. Since the planet's density is the same as the earth, that value doesn't get modified. We'll record 7 for the planet's mineral bonus, which we'll use later on.

We've placed our Frozen world directly in the second post-ecosphere lane, which means we're making a planet instead of a moon or a moonlet. Further, it's not a Gas Giant, which leaves us with either a dwarf planet or a terrestrial planet. We'll say that this planet will be a terrestrial planet (even though it might be better as a dwarf planet considering it's a post-ecosphere world). Checking the chart, we need to roll 1d10 for the Size Class and another 1d10 for density. The size roll comes up as one; the size class is 14 (13+1 = 14). The density roll is a seven, so the density is 1.1 times Earth standard (7*0.05 = 0.35; 0.75 + 0.35 = 1.10). It's a small world, but it's pretty dense; the numbers are fairly close to Mercury's actual values. Checking for PSC 14, the base values are 2.33x10²³ kilograms for mass and 0.34G for gravity. We multiply both values by 1.1 and get the final values (after rounding): the planet's mass is 2.56x10²³ kilograms, and its gravity is 0.4 gees. The mineral bonus for PSC 14 is -9. Since the density is 1.1 times Earth standard, that value gets multiplied by 1.1 and then rounded to the closest integer, for a total of -10 in this case. We'll record this value for later use as well.

Determine the planet's atmospheric density.¶

Once the planet's gravity has been determined, it becomes possible to determine its atmospheric density. This is a measure of how thick the atmosphere of the planet is, and has an effect on the planet's temperature range as well as the severity of the planet's weather. It may also be used by a GM during the course of an adventure to determine such things as whether or not the planet is subjected to a great deal of stellar 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 gravity and make a d10 roll (except for gas giants; gas giants always use the ">2.0" column regardless of their surface gravity). The row whose intersection with the gravity column contains the result of the d10 roll indicates the planet's atmospheric density. The creator will need to record the indicated density with the planet's stats. Additionally, the far right column of the same row indicates a "weather factor", which will be needed when it comes time to determine the planet's weather. The creator will simply need to record this value for later use.

/A

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
N/A	N/A	N/A	N/A	0-4	10

Earth in the Starflight Universe is the third planet of the system at α215x86. According to the SF1 survey, that planet has a Very Thin atmosphere, which doesn't really seem terribly consistent with reality. We'll give our Earth-like planet a Moderate atmospheric density; that seems a little more bio-friendly, and it's the most likely outcome of the die roll for its gravity anyway. The weather factor for that kind of atmosphere is 3.

Our Frozen world has a gravity of 0.4 gees. We roll 1d10 and come up with a six. Checking the table, this corresponds to a Very Thin atmospheric density, and a weather factor of 1.

Determine the planet's surface temperature range.¶

Once the planet's atmospheric density has been determined, the planet's surface temperature range can be determined. The temperature on a planet's surface is dependent upon two main factors: the density of the atmosphere and the planet's position within a star system. Perhaps not surprisingly, temperature has a key role in determining global weather severity.

Temperatures in the Starflight Universe are given as a categorical set over specific temperature amounts. The categories are as follows:

• Subarctic: These are very cold temperatures below what can usually be found in arctic regions on Earth, ranging from absolute zero (-273C) all the way up to about -100 C. Subarctic temps are common on outerzone worlds.
• Arctic: These are cold temperatures that can be experienced in the arctic regions on Earth. They typically range from -100C 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 the middle latitudes on Earth. These temperatures usually range from zero degrees Celsius up to room temperature, around 25 Celsius. Temperate temperatures are common throughout a planet's ecosphere.
• Tropical: These are usually warmer but still tolerable temperatures usually found in the lower latitudes and desert regions on Earth. The typical temperature range for this category is from 25C up to around 50C. Tropical temps are common in the inner ecosphere lanes, but can be experienced anywhere in the ecosphere. Tropical temperatures may sometimes be found in the second pre-ecosphere lane.
• Searing: Searing temperatures are usually too hot to support most lifeforms but still below the boiling point of water, between 50C and 100C. Searing temperatures are common in the innerzone, though occasionally they may been seen within a system's ecosphere.
• Inferno: These are extremely hot temperatures greater than the boiling point of water 100C 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 first pre-ecosphere lane and within the radius of a star's Roche limit. Particularly high Inferno temperatures may pose a significant thermal damage hazard to space vehicles and starships.
  

To determine the temperature range, a creator may simply use the table below. The intersection that corresponds to the planet's position and atmospheric density indicates the temperature range for the planet. The creator simply needs to write down the indicated temperature range with the planet's stats.

ubarctic

Planetary Temperature Range based on Atmospheric Density and Planetary Position

Position	None	Very Thin	Thin	Moderate	Thick	Very Thick
First Pre-Ecosphere Lane	Subarctic to Inferno	Inferno	Inferno	Inferno	Inferno	Inferno
Second Pre-Ecosphere Lane	Subarctic to Inferno	Searing to Inferno	Searing to Inferno	Searing to Inferno	Inferno	Inferno
First Ecosphere Lane	Subarctic to Inferno	Tropical to Inferno	Tropical to Inferno	Tropical to Inferno	Searing to Inferno	Inferno
Second Ecosphere Lane	Subarctic to Searing	Temperate to Searing	Temperate to Searing	Temperate to Searing	Searing to Inferno	Inferno
Third Ecosphere Lane	Subarctic to Searing	Subarctic to Searing	Arctic to Searing	Arctic to Searing	Temperate to Searing	Tropical to Searing
Fourth Ecosphere Lane	Subarctic to Tropical	Subarctic to Tropical	Subarctic to Tropical	Arctic to Tropical	Temperate to Searing	Temperate to Tropical
First Post-Ecosphere Lane	Subarctic to Temperate	Subarctic to Temperate	Subarctic to Temperate	Subarctic to Temperate	Arctic to Tropical	Temperate to Tropical
Second Post-Ecosphere Lane	Subarctic to Arctic	Subarctic to Arctic	Subarctic to Arctic	Subarctic to Arctic	Arctic to Temperate	Arctic to Temperate
Later Post-Ecosphere Lanes	S
Subarctic	Subarctic	Subarctic	Subarctic to Arctic	Subarctic to Arctic

Planet creators that are looking to create colonizable planets for use in their campaigns should bear in mind that a planet need only contain the Temperate or Tropical categories. Those planets may have areas that are within the other categories, as long as a portion of the planet is either temperate or tropical.

Once a creator has the temperature range for their planet, they'll need to determine how much that range will affect the planet's weather. As a general rule, the greater the range, the more of an effect that range plays out 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). To determine the effect of the temperature range on the planet's weather, the creator needs only to look up their planet's 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 won't have any weather. If the planet being created has no atmosphere, the weather factor for temperature may be ignored, though the planet will still have the temperature indicated by this step.


This is a straight-forward step for both planets. Our Earth-like world is in the second ecosphere lane and has a Moderate atmospheric density. Checking the tables above, we can see that its temperature range will be Temperate to Searing, which has a weather factor of two (this matches Earth's stats from SF1, though in reality the Earth's temperature range would probably be Arctic to Searing). The Frozen planet is in the second post-ecosphere lane and has a Very Thin atmosphere. From the tables, we see that its temperature range will be Subarctic to Arctic, which has a weather factor of three. We'll record those values for both worlds, along with the weather factors for later use.

Determine the planet's atmospheric composition.¶

The next step in the planet creation process is the determination of what mixture of gases make up the planet's atmosphere. In general, the gases in a planet's atmosphere can largely be predicted by the conditions on the planet's surface; 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 volcanism or a non-standard surface configuration) that may drastically affect a planet's atmospheric composition, resulting in a number of possible "exotic" atmospheres.

Again, determining a planet's atmospheric composition is fairly simple. Provided the planet has an atmosphere, a creator will simply need to make a d% roll and look up the results in the table below (obviously, the mix is "None" if no atmosphere exists for the planet). If a result of "Exotic" occurs, the creator will need to make a second d% roll and look up the results on the second table. 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 the mixture. Once the final atmospheric mix has been determined, the creator will need to record the indicated mixture with the planet's stats and will need to record the atmospheric constant for later use.

Planet creators that are looking to create colonizable planets for use in their campaigns 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; this is okay for any race that has adapted to the presence of an otherwise extremely poisonous gas).

itrogen, Oxygen (2)

Atmosphere Determination by Planetary Conditions and d% Roll

Planetary Conditions	0-50	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	N
Nitrogen, Oxygen (2)	Exotic	Exotic	Exotic

xygen, Hydrogen Cyanide

Exotic Atmosphere Determination by d% Roll

d% Result	Atmospheric Mix	Atmospheric Constant
0-12	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	O
2

The obvious atmospheric mix for the Earth-like world would be Nitrogen/Oxygen, but for the hell of it let's go ahead and roll it out. The Earth-like world is an Liquid World within the Ecosphere and has a Moderate Atmosphere. This corresponds to the second-to-last row of the chart. A roll of d% comes up as a nine, which indicates the Nitrogen/Oxygen atmosphere. Had it come up as an exotic atmosphere, we would have rolled again...that d% roll came up as a four, indicating a straight Nitrogen atmosphere (sans Oxygen). N₂O₂ is what we really want, so we'll just go with that.

Our Frozen world is in the post-ecosphere and has a very thin atmosphere. This corresponds to the fourth row of the table (post-ecosphere world, any density). We roll d% and come up with 96, an Exotic atmosphere. The second d% roll comes up as 73, so the planet's atmosphere consists of Oxygen and Carbon Dioxide. That might've indicated a remote chance that the planet would support some life, were it not for one tiny detail, which we'll discuss when it comes time to figure up the planet's biodensity.

Determine the planet's hydrospheric composition.¶

A planet's hydrospheric composition can be determined as soon as its atmospheric composition has been determined. This lists what compound(s) make up any liquid portion of the planet's surface. The term hydrosphere is a bit of a misnomer for a large number of planets, as its true definition is "the combined mass of water found on, under, and over the surface of a rocky planet". By definition, Gas Giants have no hydrosphere. A great many planets in the Starflight Universe don't have any kind of water on their surface or as part of their overall composition. However, since the term was used in the original games, the term will be continued here. A planet's hydrospheric composition is largely dependent upon its atmospheric composition. Planetary temperature and atmospheric density may also factor in, though there are many occasions where a planet's hydrosphere is solely dependent on the atmosphere. Planets that have no atmosphere have no hydrosphere.

To determine a planet's hydrosphere, a creator needs to find the atmospheric mix on the table below and look up the result 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 listed with a set of temperature requirements (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). If the requirements are met, the creator must roll d%; if the result is in the indicated range, then the planet's hydrosphere is set to the mix indicated by that possibility. A planet meets the requirements if the top of its temperature range is as cold or colder than the indicated temperature category. Should the top of the temperature range be colder than the indicated temperature category, the indicated mix automatically becomes the planet's hydrosphere, regardless of the result of the d% roll. Some temperature ranges indicate a level "or higher"; in these cases, the requirement is searching for that category as the bottom of the temperature range, with any higher categories automatically fulfilling the requirement. If the requirements are not met or if the d% roll does not come up in the indicated range, the creator will skip that possibility. If the creator comes to the last possibility given, that mix automatically becomes the planet's hydrosphere.


olspan=7>Water

Hydrosphere Determination 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 or Lower 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

Note that it is possible for a planet indicated as Liquid to wind up having no hydrosphere, either through having insufficient gravity to have an atmosphere or hydrosphere or through the hydrosphere selection process. In this case, the planet needs to be reclassified as a Rock world.

If the planet creator intends for their world to be habitable, their world must have a Water hydrosphere.

Our Earth-like world 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 maximum of our planet's temperature range is Searing. This is well above Subarctic, so we skip the first possibility. Water is the last possibility for Nitrogen/Oxygen, so that becomes the planet's hydrosphere. Since we're making it Earth-like, that's a Good Thing.

The Frozen planet has a Oxygen/Carbon Dioxide atmosphere with a temperature range of Subarctic to Arctic. Checking the table, we see two possibilities: Carbonated Water and Water. The first possibility is Carbonated Water. The temperature requirement of "All Temps" means that our planet meets the requirement, so the dice are rolled and come up as 16. This is within the indicated range, so the planet's hydrosphere becomes Carbonated Water. This doesn't ruin the planet's chance of supporting life, but it doesn't help it very much either.

Determine the planet's lithospheric composition.¶

The planetary lithosphere must be determined at this point in the procedure. The lithosphere is defined as the solid outermost shell of a rocky planet, and determines which elemental materials are 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 lithosphere, a creator needs to select three mineral elements at random using the table in Chapter 5.8, either by selecting whatever minerals they wish or using the d% results listed on that table. The first indicated mineral becomes the primary mineral for the world, the second one becomes the secondary mineral, and the third becomes the tertiary mineral. A single mineral can appear once in a planetary lithosphere, though it's not recommended (particularly if the appearances aren't adjacent, i.e. if the same mineral winds up as both the primary and the tertiary mineral).

Planet creators who have some knowledge of chemistry (or who have players in their group who are) might realize that certain combinations of certain mineral elements in the lithosphere and mixtures in the atmosphere or hydrosphere are impossible. It is perfectly acceptable for a creator to deliberately select minerals to replace any randomly rolled minerals to avoid these kinds of situations. The vast majority of players probably won't care and won't know enough to notice.

Rain on chemistry; we'll go ahead and pick our minerals using d% rolls. For the Earth-like world, the d% rolls are 95, 01, and 74. This corresponds to a lithosphere of Zinc, Aluminum and Silicon. For the Frozen world, the results are 86, 17 and 88. This would correspond to Titanium, Cobalt, and Titanium. It's not a good idea to have Titanium twice, so we'll replace the second occurrence. For the heck of it, we'll say Endurium (it's on the table, after all), so the final lithosphere for the frozen world becomes Titanium, Cobalt and Endurium. Sounds like the frozen world would be a good place for a mining trip in an SF1-era expedition...

Determine the planet's biodensity and mineralogical density.¶

At this point, there are only a few more vital planetary stats that need to be determined. The first stat left to be determined is the planet's mineralogical density, which is simply a measure of how much of the planet's surface contains mineable materials. In SFRPG, this value is used to determine whether or not a vehicle encounters a mineral deposit during surface exploration (see Chapter 8.2). Since they have no lithosphere, the mineralogical density of Gas Giants is always 0%. A planet's mineralogical density is dependent upon its physical size as well as its density.

The next remaining stat is the planet's biodensity (also sometimes called biomass). This is a measure of how much of the planet's surface supports higher organisms (usually anything more complex than a "carpet lifeform" such as grass). Like mineralogical density, this value is used during surface exploration to determine whether or not a vehicle encounters a lifeform. A planet's type, its atmospheric mixture, and its hydrospheric mixture all serve to determine the planet's biodensity.

Mineralogical density and biodensity are both determined at this stage of a planet's development. Earlier in the planet creation process, the creator may have recorded a value for their planet's "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 0%. 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 die modifier won't be set until the planet's atmosphere and hydrosphere are known. To find the modifier, a creator needs to use the table below and find the row that most closely matches the planet's conditions. Planets may only contain life if they are a non-gas giant located in one of the star's ecosphere lanes. Some ecosphere lanes are better than others; a -25 penalty is applied to the final roll for all worlds in the first and fourth ecosphere lanes. Should the planet's hydrosphere consist of water, an additional +5 bonus will be added to the final roll. The planet's biodensity will equal the result of the die roll plus 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%.

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 7 for our Earth-like world. That now comes into play. The roll of d% comes up as 13, so the planet's final mineralogical density is 20% (13+7 = 20), which is not all that impressive. The planet is a Liquid-type World with a Nitrogen/Oxygen atmosphere. Checking the chart for the biodensity bonus, we see that this matches the very first row, so the bonus is 15. Further, since the planet's hydrosphere is made of Water, an additional five points are added to that value, so the total bonus is 20. Finally, we know the world is in the second ecosphere lane, so this world can have life on its surface and takes no penalties from its location. The d% roll is made and comes up as 52, so the final biodensity of the Earth-like world is 72% (20 + 52 = 72). The Earth-like world doesn't have a lot of mineral value, but it does have some fairly abundant life on its surface.

The recorded value of the Frozen world's mineral bonus was -11. The d% roll for that planet comes up as 41, so the final mineralogical density of the frozen world is 30% (41 - 11 = 30). Again, that's not all that great, but it's still better than the Earth-like world. The Frozen planet is in the second post-ecosphere lane; this is not in the ecosphere, so the planet cannot have life. For the sake of demonstration, we can go ahead and figure up what it might've had if it had been in an ecosphere lane. The Frozen world has an Oxygen/Carbon Dioxide atmosphere. This matches the Frozen/Oxygen with anything else row, so the bonus is -25. Since the planet's hydrosphere is Carbonated Water, there is no bonus there, so the final overall bonus is -25. The d% roll comes up as double zero, which would give a final result of -25% (0 - 25 = -25). However, since the biodensity can't be less than zero, this value gets reset to zero. The planet turns out to be completely lifeless (well, not if you count the Endurium...)

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 a 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 various factors (including incoming solar radiation, 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. The Starflight Universe (and SFRPG along with it) takes a bit of a shortcut when it comes to weather by listing weather categories instead of precise conditions.

For those who are curious: yes, the method for determining weather in SFRPG is based on some real meteorology (the key words there are based on). SFRPG 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 those winds can become (particularly surface winds), the more severe the weather. 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 forces is highly generalized in the game, and players and even planet creators shouldn't have to deal with the inner workings of the math (a good thing too, as it's a fairly complex differential equation).

To determine the planet's weather, a creator must begin 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 must then take the planet's gravity, rounding it down to the nearest whole number, and add that to the previous result. The planet's temperature weather factor (which the creator should have recorded earlier) is then added to that amount. The final result is the planet's weather intensity index.

At this point, the creator should make a roll of 2d10 for unusual conditions. If the result of the roll is zero, then the creator should add five points to the intensity index. Additionally, they should lower the planet's biodensity by 5% (if possible). If the roll comes up as eighteen, then five points should be subtracted from the intensity index. On any other roll, nothing is added or subtracted from the index. Once the final intensity index has been calculated, the creator need only look up the result in the table below to determine the proper weather category.

ery Violent

Planetary Weather Categorical Index Values

Weather Index Value	Planetary Weather Category
<5	None
5-9	Calm
10-14	Moderate
15-19	Violent
>19	V

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


Gas Giants have incredibly turbulent atmospheres, regardless of all other conditions. If the planet is a Gas Giant and the resultant weather index comes up as 14 or less, the final weather category should be Violent regardless. All other values should be treated as normal for Gas Giants.

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

Our Earth-like world had a Moderate atmospheric density (with a weather factor of three), a Nitrogen/Oxygen atmosphere (which has an atmospheric constant of 2), gravity of 0.9 gees, and a temperature range of Temperate to Searing (which has a weather factor of 2). We begin by multiplying the atmospheric constant by the density weather factor; we have six so far (2*3 = 6). We then add to that the 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 is eleven, so nothing is added or subtracted from the index. The final intensity index value is eight. Checking the table, we see that this corresponds to a category of Calm.

The Frozen-world has a Very Thin atmospheric density (factor of one), an Oxygen/Carbon Dioxide atmosphere (constant of 3), a gravity of 0.4 G, and a temperature range of Subarctic to Arctic (factor 3). The final intensity index value is six. (3*1 = 3; 0.4 rounds down to zero; 3+0 = 3; 3+3 = 6). This also corresponds to Calm weather.

Determine the planet's value as a colonizable world.¶

Finding suitable colony worlds was part of the backstory of both of the original Starflight games; it was a means by which Arth's High Council would preserve Arth culture, should the situation at hand result in the annihilation of all life on Arth. Interstel crews were charged with exploring star systems in an effort to find suitable worlds; to make it worth their while, substantial rewards were offered to any crew that found a good candidate planet. Colony recommendations were therefore a major source of revenue for the player in the original games, and the same can be true of player groups in SFRPG. The next step in the planet creation process is to determine how valuable the planet will be should a starship crew submits a colony recommendation for the planet.

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 technically does meet this criterion). Similarly, the atmospheric density does not matter.
• The planet must have a hydrosphere and that hydrosphere must contain Water.
• The planet's temperature range must contain either the Temperate category, Tropical category, or both. Note that the planet can contain other temperature categories; it only matters that one of the two indicated categories are present.
• The planet's weather may not be Violent or Very Violent; all other categories are acceptable.
• The planet's 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 value.
  Any planet that does not meet all of these criteria cannot be colonized, and has a value of zero. Note that this does not remove the world from consideration for other purposes, such as becoming a homeworld (the homeworld of the Tandelou Eshvara is a good example of this kind of planet; its gravity is too high and its weather is too rough).
  

Should a planet meet all of the criteria necessary to be considered a colony world, and the planet's designer does not intend to make it an inhabited world, then the planet must be assigned a monetary value. To do this, roll 1d10. 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. If the planet's biodensity is 75% or higher, add 5000 to the base value. 5000 should also be added to the base value if the planet is an optimal gravity world. After making adjustments for abundant life and gravity, the final amount indicated is the planet's overall value. This value should be placed somewhere in the planet's notes (it's alright to place it in the "Community Notes" section of the Planet Record Sheet, as the world shouldn't have any communities on its surface).

If a planet does not meet all of the criteria for being a colony world, but is recommended anyway, the crew that recommended the planet will face a fine. To calculate the fine, 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 planet fails to match. The final result is the total fine levied against the crew. GMs may choose to be merciful and only issue a warning rather than a fine the first time a crew botches it up, if they're feeling merciful. If not...

The Earth-like world has a Nitrogen, Oxygen atmosphere, Water hydrosphere, Temperate to Searing temperature range (which contains both the Temperate and Tropical categories), and Calm Weather, all of which match colonization criteria. With a gravity of 0.9 gees, this planet is not only a habitable world, it is an optimal one. The d10 roll comes up as an eight; the base value is going to be 40,000 for this world. 5000 is added due to it being an optimal world. The 72% biodensity puts the world just out of range for an additional bonus, so the final value of the world is 45,000, a pretty good catch.

The Frozen world is obviously not a colonizable planet. However, the base value of a fine can be readily determined for this world, if someone out there is dumb enough to recommend it. It does have an Oxygen, Carbon Dioxide atmosphere, so that criteria is met. Carbonated Water does not meet the criteria, so that would add 5000 to the fine. The Subarctic to Arctic temperature range is another strike against the world; the fine is now up to 10,000. Its weather is calm and its gravity is below two gees; those criteria match. So, 10,000 is the base value of a fine for this world.

Determine the planetary geography (if necessary).¶

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

All planets in the original games used Mercator projections (more commonly just called Mercators) to map out their surface features. A Mercator projection is a cylindrical map projection, 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 to use than most other cartographic methods (more importantly, they allow surface navigation on a two-dimensional grid). Mercators are also used in SFRPG, though whether or not they are entirely necessary is another matter when it comes to the planet creation process. If there's a chance that a player group will visit a world, it behooves the planet's 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 layout of their world more logical. Planetary type is perhaps the best predictor what's appropriate for its surface geography, but other stats may come into play as well (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 as necessary for gas giants as they are for rocky worlds (anything other than a gas giant). Since a gas giant has no solid surface, there isn't a surface to map out, and its atmosphere consists of turbulent gases flowing at significant speeds. This creates an ever changing "landscape" that's almost impossible to map out. That's not to say that a creator can't make a Mercator for their gas giant, but since it's obsolete almost the moment it's finished (and since surface navigation on a gas giant is impossible), there's almost no point in making one. For those that insist on making Mercators for these worlds, creators should consider mapping the locations of any significant, long-lasting storm systems on the surface (such as Jupiter's Great Red Spot or Saturn's north polar hexagon).

One thing a creator should consider is whether or not their world has active vulcanism. For Molten planets, this one's obvious. Other planets may or may not have volcanoes. 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 or volcanic ash. Rocky planets that have no vulcanism acquire what's known as an "old" surface, which simply means that it's pockmarked with craters. These planets tend to have large shifts in elevation, and as a result the terran is smoother. With volcanoes, planets have a relatively smoother surface (what's known as a "young" surface). Planets with significant weather also tend to have younger surfaces than those with no weather (or no atmosphere, for that matter).

In the original games, planetary surface features were usually indicated by changes in the elevation of the planet's terrain. Each planet had a color scale (usually with anywhere from six to eight "levels") based on the planet's type that could be viewed alongside the planet's Mercator. The highest planetary elevations corresponded to the color at the physical top of the scale, while the lowest elevations (corresponding to oceans, inland seas, icepack or lava seas) were always at the bottom of the scale. Images of these original color scales are available in the table below.

Elevation Color Scales by World Type from SF1/SF2

Frozen	Gas Giant	Molten	Liquid / Rock (Life Bearing)	Liquid / Rock (Non-Life Bearing)

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

All world types will tend to be shaped by the placement of continents, as well as the placement of mountains and the planet's temperature range. Any oceanic regions will tend to be frozen into icepacks if the temperature is Arctic 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 regions, though usually these will be more common on the "windward" side of any mountain ranges that lay perpendicular to the planet's prevailing winds (which can be set at the creator's discretion). Open plains and plateaus may also be found in these areas. Desert regions may be found on the leeward side of mountains, or areas where the temperature is Searing or hotter. Desert regions are also common within the 28-32 degree latitude regions (this has to do with the mechanics of atmosphere transport; on Earth, it explains the presence of deserts such as the Mojave, the Sahara and the Australian Outback). Other terrains such as inland rivers, plains, plateaus, canyons, and caves can be added after these major features have been added. Worlds built with these features in these places will have a number of terrain types that mimic real planetary geological and meteorological interactions.

Since the design of a Mercator is basically something that happens on the whim of the planet's creator, the examples in this section are going to show a couple of 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 our Earth-like world, we're going to use the planet's grid-lines as delimiters for the terrain, which is a perfectly valid way of creating a Mercator map. We're gunning for a Liquid world, 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 long, low-lying land masses spread throughout the west. We'll go ahead and use the Liquid life-bearing elevation scale for the terrain, using colored pencils to fill out the Mercator. The final result looks like this:

This map uses the planet's grid-lines to mark out the terrain, resulting in a "classic" style Starflight Mercator.

For our Frozen world, 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 a steppe plateau, with some mountainous terrain in the northern/western hemispheres and a southern continental sea. We'll use the Frozen elevation scale as it appears above for this world (at least, as close as we can get to it using colored pencils...

For this Mercator, the designer elected to use a more "natural approach", rather than base features strictly off the coordinate grid.

Create lifeform lists for the planet (if necessary).¶

The presence of life on a planet's surface adds another level of complexity to a planet, as life indicates the presence of an ecosphere, a global ecological system integrating all living beings and their relationships, including their interaction with the elements of the lithosphere, hydrosphere, and atmosphere. Ecospheres are fabulously complex systems, given everything that goes into them. If taken in whole, they complex enough to utterly defy any attempt to make a simple system out of them.

The original games (Starflight I in particular) made a valiant attempt to create a realistic ecosphere. The system in the original games was based on the presence of significant lifeforms, ones that were big enough to be worth money when those lifeforms were captured and sold. SFRPG follows this basic idea; though there may be a number of lesser lifeforms on a planet's surface, those lifeforms are ignored in favor of the largest and most valuable lifeforms on the planet. These large lifeforms are known as megaflora (large producers) and megafauna (large consumers), or collectively as significant lifeforms, and correspond to the same lifeforms listed in Chapter 5.7 (the forty-two lifeforms that appeared in Starflight II). Planets may or may not have an explicit listing of which of these lifeforms are present, what's known as a lifeform list in SFRPG.

If a planet has any biodensity rating greater than 0%, the planet's creator will need to decide whether or not they wish to make an explicit lifeform list for their planet. It is acceptable for a creator to not create a lifeform list. Not creating a list transfers the responsibility of generating the list to the GM of any adventure or campaign in which the planet is featured. It gives the GM more latitude to be flexible in their decisions and opens the world up for the GM 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 if the GM would've wanted to make lifeforms from scratch). All lifebearing worlds in the Delta Sector have lifeform lists, which are included with the remaining planetary stats in the Starflight II Survey. While there is some evidence that would suggest the worlds of the Alpha Sector have explicit lifeform lists, those lists (if they even exist) have never been released publicly. This means there is no way for any independent survey team to know when they'd managed to view every possible lifeform on a planet's surface. In effect, all of the lifebearing Alpha Sector worlds are worlds without lists.

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

With the number of lifeforms selected, the creator must decide which lifeforms will be on the planet. This boils down to one of three options: they may select a list made up of SF2 lifeforms, they may use the creature creation rules outlined in Chapter 10.2.5 to create custom lifeforms on their own, or they may use a combination of the two. Creators are welcome to select whatever lifeforms they desire for their world without consideration of their lifeform's niche; it's assumed that there are sufficient numbers of "insignificant lifeforms" which players will not encounter but will be able to sustain significant lifeforms. If the creator would like to select their creatures at random, they may roll d% for each random lifeform desired and use the table below. The creator always has the right to ignore the result of a randomly indicated lifeform, or to generate custom lifeforms on their own volition. Lifeforms cannot appear on a list twice; if a lifeform would occur twice as the result of a random selection, a new roll must be made.

ellow Hugger

Lifeform Selection by d% Roll

d% Result	Lifeform
0-2	Black Acid Squirter
3-4	Brass Harpooner
5-7	Breathing Cactus
8-9	Crystal Sponge Plant
10-10	Dark Lightning
11-13	Eight-Legged Rhino
14-16	Electric Balloon
17-18	Expanding Hippo
19-20	Funnel Tree
21-22	Fur Tree
23-24	Glowing Spinner
25-26	Green Balloon
27-28	Green Blob
29-31	Grey Anemone
32-33	Hill Rat
34-35	Hive Plant
36-38	Hot Fungus
39-40	Humanoid Hopper
41-41	Humming Rock
42-43	Nid Berry Bush
44-46	Oily Spore Bush
47-49	Parachute Spider
50-52	Peacock Tree
53-54	Plant Bird
55-57	Poison Glider
58-59	Pop Berry Plant
60-62	Psychic Blaster
63-64	Pulsating Gummy
65-67	Purple Screecher
68-70	Red Puff-Wart
71-72	Rocket Melons
73-74	Running Fungus
75-77	Sandpit Stalk
78-79	Scaly Blue Hopper
80-81	Single Leaf
82-84	Spinning Crab
85-86	Sticky Fruit
87-89	Stinging Cone
90-91	Vacuum Slug
92-93	Wandering Chandelier
94-96	Wheel Snake
97-99	Y

Our Frozen world had a 0% biodensity. Thus, it has no lifeforms of any significance and does not need a lifeform list. Our Earth-like world, however, had a 72% biodensity, so we can go ahead and create a list for it. To save time, we'll say that the world will use the lifeform list from SF2 and we'll let the dice determine the planet's biosphere. We begin by rolling 1d10 to see how many lifeforms there are. The roll comes up as zero, so we roll again. This time a five comes up, so we'll place five lifeforms on the planet. We roll d% five times, and come up with 48, 53, 48, 9, and 27. From the table above, we can see that this (respectively) corresponds to Parachute Spider, Plant Bird, Parachute Spider, Crystal Sponge Plant and Green Blob. The Parachute Spider gets duplicated, so we must re-roll for the second occurance. The re-roll comes up as 44, indicating Oily Spore Bushes. So, our planet's lifeform list final lifeform list is Crystal Sponge Plant, Green Blob, Oily Spore Bush, Parachute Spider, and Plant Bird.

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

Once the planet’s geography is determined, a number of communities may be created on a planet’s surface using the procedure outlined in Chapter 10.2.3. 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 communities on a planet's surface should, however, consider the planet's level of habitability when answering the question of how many communities to put on the surface of their world.

The planet doesn't need any communities if it is uninhabitable (no Oxygen in the atmosphere and/or no Water in the hydrosphere); if a creator does decide to put communities there, they should be limited to single, relatively small communities. Part of the community's makeup should include such objects as pressure domes, humidity windtraps and collectors, large oxygen or water tanks, and so forth. In other words, since the planet itself cannot sustain life on its own, the community must either produce or be supplied with what it needs for its own continued existence. GMs may ultimately decide to make shortages of these supplies the focus of an adventure.

A planet that has a Nitrogen/Oxygen atmosphere and Water hydrosphere but has something else out of whack (temperature too hot or too cold, gravity higher than 2 gees, or violent weather) may have more communities on them than uninhabitable worlds, but again these communities will likely be small and relatively dispersed. The homeworld of the Tandelou Eshvara (δ35x69, p4) is a prime example of such a world; its gravity is 4.15 Gs and the weather is Violent. 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, or even full-on pressure domes. They are liable to not be as restricted as communities on uninhabitable worlds, though they won't offer the total freedom of planets on more habitable spheres. A recommended number of communities for this kind of world is 1d5 communities of Village or Small Town size, 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 can exist on their surfaces. These are your run of the mill towns; usually any external covering or emergency supplies they have are strictly for defensive purposes (and the vast majority of these communities will forgo the bulk of these, particularly in more advanced societies). The recommended number of communities for these worlds is 3d5 communities of Small Town or Large Town size, with a progressive double or triple the number of smaller communities and a progressive half or third (round down) number of larger communities. For optimally inhabitable planets (planets with gravity of 0.7 to 1.3 gees), this can be changed to 3d5 communities of Large Town or Small City size.

The numbers and die rolls recommended above are for fully inhabited planets and a creator should feel free to create fewer or smaller communities for their worlds 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. Again, those numbers above are simply recommendations.

When the number of communities on a world has been determined, they should be placed on the planet's mercator map. Ideally, communities should be placed close to sources of food, water, and natural resources if possible. If the community is ancient, it may be built on 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 to fill in the details of those communities that have been created. The information in Chapter 10.2.3 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 product, total population, and predominant power structures on the planet can be filled in, though its recommended the creator have a campaign in mind if they go to this amount of trouble.

Once any communities have been created, the planet is ready to be used. If the creator desires, additional details may be added to the planet, such as locations of archaeological dig sites or ruins, the length of day, color of the sky, and so forth. These details may be used to help "flesh out" the world, and may serve to make it a more vibrant, living place. For a working example of a fleshed out habitable planet, planet creators should check out the playtesting version of Koann III in Chapter 12.4.1.

Our Earth-like will is an optimally habitable world, so let's muck it up a bit by throwing some communities on the surface. A roll of 3d5 comes up as 11. We'll 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 would be anywhere from three to five Small Cities, one or two Large Cities, and maybe a Metropolis. Going with the minimum numbers there, the planet will need a grand total of 345 communities, meaning we've got a lot more work ahead. Perhaps we'll leave that work up to a GM. Better yet, we could just change our minds entirely and leave the planet in its previous pristine state...

The Frozen world qualifies as uninhabitable, since its hydrosphere is made of carbonated water. We don't need any communities on its surface, but for the heck of it let's put a Rural Village on its surface. There are some valuable minerals on the surface after all; it'd make sense if someone was out there braving the cold in order to collect and process them. It might have a water treatment station to take the fizz out of the water and a pressure dome for heating purposes, as well as to replace the atmosphere with something less caustic. The community might actually be a good place for a brewery; the planet's a natural refrigerator and the water's carbonated. Put the community in the "tropics" (where the water might still be liquid-phase) and it'd be fairly well set. Now, how to grow the hops on a frozen world...

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