Celestial Bodies

This page discusses the game mechanics for celestial bodies. For a list of all space bodies in Terra Invicta, as well as their stats, see Space Body List instead.

Celestial Bodies are bundles or rock, gas and minerals of different sizes and composition found throughout the Solar System. They are the primary targets of the industrialization of space and the locations where the vast majority of human and alien infrastructure is constructed around (Lagrange points being the exception). The number of bodies depends on the System setup at the beginning of the campaign, but objects are always present in the game up to a distance of 50 Astronomical Units from the Sun (up to the Kuiper Belts)

Saturn and his satellite bodies, as seen at the beginning of the campaign.

Body types and Composition

There are four categories of Celestial Bodies (discounting the Sun): Planets, Dwarf Planets, Natural Satellites and Asteroids. There are 1 to 25 locations on almost each body where ground Habs can be built. Some satellites are considered asteroids while others, such as large moons, are more similar to dwarf planets and indicated as planetary satellites in the game.

Asteroid bodies can have varying composition in the game, while the particular resources one can extract from them are unique to each individual body and can differ drastically between playthroughs based on resource rolls.

Determining the exact resources available requires either a probe to be sent, or a ship with a Mobile Space Science Lab to perform a survey operation.

Tip: If you want to send many probes there is a one-click option in the Intel -> Solar System tab.

Ground sites and Orbits

Excluding the Gas Giants and Venus, most space bodies have at least 1 site that allows ground habitation. Small asteroids and moons typically only have 1 site, while larger moons and planets can have up to 25 sites. Smaller space bodies also restrict the maximum tier of hab that can be constructed on them.

In term of orbits, the situation is more varied. Low and High orbits are found on most bodies (some asteroids have "parking orbits" instead), but larger planets and even the gas giants support additional orbits of their own, some of the other common nomenclatures are: Inclined, Medium, Intermediate, Extreme and Synchronous; but the altitude, graviational pull, and the number of possible stations in the orbit are unique to each and every one of them for every body (though station number caps are typically 1 for asteroids and inclined orbits, 4 for dwarf planets and some moons, and 8 for the rest).

Most (if not all) low orbits have the interface option with the respective body, which allows several interactions through the use of specific hab and ship modules, especially when the body is Earth. Finally, two exclusive orbits are found in the game, corresponding to those of the International Space Station and Tiangong Station around Earth. Only 1 station can orbit those configurations at a time, and they are also considered interface orbits: they effectively correspond to inclined low orbits.

Resources and Body utility

The five basic space resources ( Water, Volatiles, Metals, Nobles, and Fissiles) can be found in these bodies. Their abundance and distribution depend on dice rolls cast during world generation.

Regardless, some celestial bodies can be always far more valuable than others in terms of resource placements and utility. Early resources in the Moon for instance, are far lower than Mars (which is typically the main expansion point in the early game). Space bodies in the outer solar system are also generally richer to encourage further expansion. Different bodies and orbits do, at the end of the day, carry material or strategic value depending on the player's needs in a given campaign.

Resource Formulas

This section discusses how the output values for each hab site are calculated. For a list of hab sites and mining profiles, as well as their stats, see Hab Site List and Mining Profile List instead.

The game assigns every hab site a mining profile, which is essentially a set of values used by the randomizer to determine the resource outputs of the hab site. Specifically, for each of the five basic space resource types X, the mining profile contains:

• X_mean: The median output value for resource type X.
• X_min: The minimum output value for resource type X.
• X_jump: The chance to jump the output value away from the median for resource type X. (An unlimited number of jumps are possible.)
• X_width: The distance moved by each jump.

The mining profile also contains the special true or false value:

• modifyBySize: Whether the above values should be modified by the space body's mass and density.

The mass and density modifiers are calculated as follows:

 Mass Modifier = Min(1, Space Body Mass (kg) / 50000000000000000 kg) 

 Density Modifier = Min(1, Space Body Density (g/cm³) / 1.25 g/cm³) × Max(1, Space Body Density (g/cm³) / 3 g/cm³) 

If modifyBySize is true, then the Mean and Min values are modified as follows:

• For Water and Volatiles:

 Actual Value = Base Value × Clamp(Mass Modifier, 0.75, 1.25) 

• For Metals, Nobles, and Fissiles:

 Actual Value = Base Value × Clamp(Mass Modifier × Density Modifier, 0.75, 1.25) 

Regardless of whether modifyBySize is true, these numbers are also multiplied by the Mining Productivity Rate. This is a slider you can adjust in Custom Campaign Settings. When playing with a Full Solar System, it is 100% on Long Campaign mode and 200% on Accelerated Campaign mode. Smaller Solar System sizes increase this setting to compensate for the fact that they have significantly fewer hab sites.

The Width values are also modified by the Mining Productivity Rate as follows:

• If Mining Productivity Rate < 200%, then:

 Actual Width = Base Width × Mining Productivity Rate 

• Otherwise:

 Actual Width = Base Width × (2 + Mining Productivity Rate ^ (1 - Jump) ) 

Finally, if the Min values are greater than 0, then they are also randomized as follows:

 Actual Min = Base Min × (0.8 to 1.2) 

After all these modifiers are applied, the game now calculates the hab site's monthly output value V for each resource type X as follows:

1. Repeatedly flip a weighted coin with X_jump chance of landing on heads, until it lands on tails.
2. Set V to the number of heads.
3. 50% chance: Multiply V by -1.
4. Multiply V by X_width.
5. Add X_mean to V.
6. Add a random value between -(X_width / 2) to (X_width / 2) to V.
7. If V is less than X_min, then set V to X_min.
8. If V is less than 0.01, then set V to 0.

In the case of Nobles, there is one final modification:

1. Let M be the Metals output value, and N be the Nobles output value.
2. Divide M by either 2 or 3 (50% chance for each).
3. If N > M, then set the Nobles output value to M.