C-System Bodies

System Bodys

Colony Cost

The colony cost algorithm has been updated for C# Aurora to include hydrosphere extent, low gravity and tide-locked worlds and to change the rules for dangerous gases and max pressure. The new calculation is as follows:

Gas Giants, Super Jovians and worlds with a gravity higher than species tolerance cannot be colonised and therefore have no colony cost. Every other body has a colony cost that is equal to the highest colony cost factor from the following list:

Temperature: If the temperature is outside of the species tolerance, the colony cost factor for temperature is equal to the number of degrees above or below the species tolerance divided by half the total species range. For example, if the species range is from 0C to 30C and the temperature is 75C, the colony cost factor would be 45 / 15 = 3.00. The colony cost factor for tide-locked planets is 20% of normal, so in the example given the colony cost factor would be reduced to 0.60.

Atmospheric Pressure: If the atmospheric pressure is above species tolerance, the colony cost factor for pressure is equal to pressure / species max pressure; with a minimum of 2.00. For example, if a species has a pressure tolerance of 4 atm and the pressure is 10 atm, the colony cost factor would be 2.50. If the pressure was 6 atm, the colony cost factor would be 2.00, as that is the minimum.

Breathable Gas: If the atmosphere does not have a sufficient amount of breathable gas, the colony cost factor for breathable gas is 2.00. If the gas is available in sufficient quantities but exceeds 30% of atmospheric pressure, the colony cost factor is also 2.00.

Dangerous Gas: If a dangerous gas is present in the atmosphere and the concentration is above the danger level, the colony cost factor for dangerous gases will either be 2.00 or 3.00, depending on the gas. Different gases require different concentrations before becoming 'dangerous'. Halogens such as Chlorine, Bromine or Flourine are the most dangerous at 1 ppm, followed by Nitrogen Dioxide and Sulphur Dioxide at 5 ppm. Hydrogen Sulphide is 20 ppm, Carbon Monoxide and Ammonia are 50 ppm, Hydrogen, Methane (if an oxygen breather) and Oxygen (if a Methane breather) are at 500 ppm and Carbon Dioxide is at 5000 ppm (0.5% of atmosphere). Note that Carbon Dioxide was not classed as a dangerous gas in VB6 Aurora. These gases are not lethal at those concentrations but are dangerous enough that infrastructure would be required to avoid sustained exposure.

Hydrosphere Extent: If less than twenty percent of a body is covered with water (less than 20% Hydro Extent), the colony cost factor for hydro extent is (20 - Hydro Extent) / 10, which is a range from zero to 2.00.

Low Gravity: If the gravity of the body is lower than the species tolerance, the colony cost factor for gravity is 1.00. In addition, the overall colony cost for the body will be suffixed by 'LG', for example 2.00 LG, which indicates that low gravity infrastructure is required for any population on that body. Normal infrastructure will not count toward the supported population. Date 03.03.2018

Low Gravity Bodys

Any low gravity bodies (below the minimum gravity of the colonising species) will now have a normal colony cost calculation (based on atmosphere, temperature, pressure, etc.) and an 'LG' suffix will be added. For any bodies with an LG suffix, the maximum supported population will be based on the available LG-Infrastructure.

For example, for a colony cost 2.00 world you need 200 infrastructure per 1m pop. For a colony cost 2.00(LG) world, you will need 200 LG-Infrastructure per 1m pop and normal infrastructure will have no effect.

Both normal infrastructure and LG-Infrastructure can be used on a world with gravity in the tolerable range. Worlds with gravity above max species gravity will not be colonizable.

Civilian infrastructure production on a low gravity world will be LG Infrastructure, produced at one third of the normal rate (same overall cost). Trade in infrastructure will be low gravity to low gravity or acceptable gravity to acceptable gravity. Date 06.12.2018

If the gravity of the body is lower than the species tolerance, the colony cost factor for gravity is 1.00. In addition, the overall colony cost for the body will be suffixed by 'LG', for example 2.00 LG, which indicates that low gravity infrastructure is required for any population on that body. Normal infrastructure will not count toward the supported population. Date 03.03.2018

Population Capacity

A new concept, Population Capacity, has been added to C# Aurora. This represents the maximum population that can be maintained on a single body and is primarily determined by surface area. This is the total of all populations on the same body, not per population.

The Earth's population is currently seven billion. However, the rate of population growth peaked at 2.1% at four billion, has been dropping since then (now 1.2%) and is projected to reach close to zero around eleven billion

https://ourworldindata.org/world-population-growth/

Therefore, I am going to use twelve billion as the baseline max capacity for an Earth-sized planet and four billion as the point at which growth rates are affected. Growth will follow the normal rules for up to 1/3rd of max capacity and then will fall off at a linear rate, hitting zero growth at max capacity (replicating the situation on Earth). The max capacity of a body will be equal to: (Surface Area / Earth Surface Area) * twelve billion. I will add some tech options to improve that capacity, particularly for smaller bodies. A planet can physically hold more people than the max capacity but this will result in unrest due to overcrowding.

While 70% of the Earth's surface is water, that plentiful water also improves living conditions (the majority of the world's population is less than 100 km from the nearest coastline). However, there does come a point when too much water will reduce the available living space. Therefore, once water covers more than 75% of the planet, capacity will drop at a linear rate, falling to 1% of normal capacity at 100% water. The 1% assumes a few, small, scattered islands or some form of colony floating on the surface.

Tide-locked worlds (one side always facing the star) have only 20% of normal capacity (after taking into account surface area and water). This is to simulate that the population will be living in a narrow band between the light and dark hemispheres of the planet. To compensate, these worlds also have an 80% reduction in the colony cost factor for temperature (as they are living in the temperate band).

Regardless of the result of the above calculations, a body with gravity at or below the species maximum that is not a gas giant or super-Jovian will always have a capacity of at least 50,000.

The above rules result in the following population capacities

http://www.pentarch.org/steve/Screenshots/PopCapacity.PNG

EDIT Jan 21st 2017: Each Species has a population density modifier. This is normally set to 1 but there a small chance it can be higher or lower for random species. Player-created species can specify this density. Date 21.91.2017