actual impact of atmosphere

[kingcarrot]

(totally new player here, awesome game so far )

So I simply cannot find detailed information regarding the impact of the atmosphere.
I rolled a lot of unclassified planets (with forced alien life), and no matter what, it ended up with insidious atmosphere.
What is the actual impact of the different levels of atmosphere?
I can see from the manual that the following exists:
0 Perfect atmosphere for humans.
1 Imperfect. Filters needed to breathe.
2 Insufficient. Envirosuit advised. Filters probably won’t cut it.
3 Toxic. Envirosuit necessary.
4 Insidious. Instant death without Envirosuit.

What is the actual impact? Is it simply a cost modifier? I can see that I start with Envirosuits if it is insidious. Do they simply make things more expensive?
(I ended up rolling a Siwa planet instead, simply to avoid the extra complexity for my initial game).

What about Atmosphere thickness?
I cannot see the actual heaviness, but during generation it says at least:
Heavy
earthlike
thin

What is the gameplay impact? The manual tells about the basics regarding the weather.
But what about game impact?
At what level will it impact breathability?
Will thin give a minus to the breathability? Will Heavy?
It seems like it says something regarding impact on airforce. Heavier atmosphere gives wider range I guess?

Anything else gameplay-wise?

[Twotribes]

cant answer most of that but the thickness effect aircraft if you use them and hot heavy atmosphere results in LOTS of rainfall.

[zgrssd]

Environmental Suits (basically Space Suits), Combat Armor, Battledress and Vehicles all provide a complete Environmental protection. Basically you walk around in a mini-spaceship.
For the time being, E-Suits are simply the earliest form of armor with no specific downside. You want to use them as armor anyway, as the infantry needs every extra HP they can get. The cost is negligible.
You generally start with the tech for E-Suits, but the initial designs usually omit it. Unless the atmosphere demands it, like this. So mostly a bonus, but you have to expect enemy militias to also have E-suits.

Breathability:
If you got 500 mBar atmosphere, you need ~twice earths Oxygen content to have it humanly breathable.
If lack of Oxygen is the only bad part in the Atmosphre, Filters will do. But there might be dangerous chemicals, agressive alien pollen and whatnot in the atmosphere too. So even if you got decent Oxygen content and pressure, you can be.
For aircraft, a figure of thumb is comparing gravity and airpressure. Earth is defining 1 G and 1000 mBar, so if they are out of proportion this can make Aircraft really good or Mars-level bad.

[ObeseMonkey]

The content of the atmosphere also affects the ability to open fame or not. It’s possible to have a planet where one can open farm, but still need enviro-suits to breath for example. I want to say it might effect how large the pop generated during colonisation is too, but I have no evidence for this.

As a side note, cause it took me a little time to work this out. When you pick the size of the planet it does literally mean that and not the map size. So a larger planet will have more gravity and probably a less insidious atmosphere.

[zgrssd]

ORIGINAL: ObeseMonkey

As a side note, cause it took me a little time to work this out. When you pick the size of the planet it does literally mean that and not the map size. So a larger planet will have more gravity and probably a less insidious atmosphere.

Not just the map size.
Picking a planet does affect the mapsize.

You are right however that it also affects the mass of the planet, thus gravity, thus ability to maintain atmosphere-.

Prior to the history classes, we had to look for very specific properties on every step to get life on a Siwa Planet:
- high gravity (~0.4g for small)
- decent age (~5 billion years)
- decent temperature (~15 °C)

However, history classes will overwrite any "realism" constraints that might exist.
If I tell it a moon should have alien life, it will generate a atmosphere and life not mater what realism says.
Indeed we rarely to never had non-carbon/oxygen/water life prior to the calsses. Now it is common - because it is the only way for the engine to make alien life happening.

[Mina]

Check page 160 and 161 of the manual for the information you want. Generally:

- Any level of non-terran atmosphere, biological hazard, inclement temperature, or background radiation, will mean that your population will suffer morale penalties or casualties. A Single Asset with its required upkeep will protect ALL population in that hex from ANY Atmospheric, Biological, or temperature based environmental hazard. A fair amount of radiation hazard protection is provided too, but in some circumstances this can go beyond the base generic asset protection, and can require the Radiation Treatment Asset, Anti-Radiation infrastructure, or both. Insufficient environmental protection can also cause population migration, and greater ease of military/colonial recruitment from an affected population. Free folk settlements are assumed to be adapted to environmental hazards either from their own infrastructure or genetic modification, but IF they are suffering environmental hazards somehow, they are more likely to migrate to your cities, assuming those cities have adequate environmental protection.

- Non-Terran atmosphere, biological hazards, or inclement temperature, will reduce the output of Open farming assets, depending on the severity of the environmental hazard. In these circumstances you will be required to use either Xeno Farming (If the planet's native life has any nutritional value), domed farming, or Hydroponic food factories (once researched). A late game tech can mitigate some of this hazard for open terran farming but it's not worth it.

- Your soldiers are also affected by Atmospheric/Biological hazard and will suffer morale penalties and attrition as well. This can be mitigated or cancelled entirely by issuing them with Filters (For minor atmospheric/biological hazards), thermosuits (For moderate temperature hazards), both, or Envirosuits for greater protection and also radiation mitigation. This increases the cost of infantry in the early game, however the first infantry armor upgrade includes an envirosuit, and higher levels of troop armor also include environmental protection. Vehicles also provide environmental protection by default.

As far as atmospheric thickness, that mainly affects the Air forces module. Heavier atmosphere will increase the lift generated by aircraft wings, and the force generated by propeller engines, but also the effect of atmospheric drag. Thinner atmospheres have less atmospheric resistance, but will also require more wing area to give the necessary lift for flight, and reduce the efficiency of propellers. The combination of atmospheric thickness and gravitational force will affect how you design your aircraft and how effective they can be. Planets with insufficient atmosphere for propeller-driven or aspirating (oxygen-using, Jets+Turbojets) aircraft engines can only use rocket engines for propulsion.

Atmospheric composition also might mean certain industrial technologies are not available to you. Atmospheres without significant CO2 content cannot use Methane Synthesis plants, and Water Atmospheric recomposition will require a specific combination of certain gasses to be present.