Trying to do atmospheric planets is an utterly gargantuan task that is far greater than simply throwing together some basic air resistance a few templates for life.
A basic start is that they need to look at the current chemical composition, temperature and lighting/radiation conditions of the planet. After applying a healthy dose of chemistry to the whole thing, then they can figure out what the actual end result of the chemical nature of the planet and atmosphere is and whether it has any liquid oceans, any ongoing precipitation as well as any volcanic activity. This alone is quite a task; it's a fair amount of work to figure out what a single planet would be but to script a fully generalised planetary chemical simulator is staggeringly difficult and would probably take years of collaboration between chemists, astrophysicists and coders.
After that, there's the even bigger task of determining which of those chemistries are able to sustain life. We all know that carbon, hydrogen and oxygen mix together to create life, but what about silicon/silicone based life forms? What about replacing the water as a solvent with ammonia, hydrogen sulphide or even hydrocarbons? Can phosphorous or nitrogen polymerise to form organic molecules? How might metals interact with these other chemical compositions? Which of these compositions would remain stable yet workable at the temperatures, magnetic fields and radiation levels for a given planet?
And that's all before we even get to where the life on the planet would actually be or what form it would take. Even before we worry about whether it would be more plant-like and photosynthesise for energy, or whether they would remain lithovorous and subsist on unstable minerals in the planetary crust or around vents, we would need to get the basics of their chemistry down. Depending on their chemistry, they would then alter the planetary atmosphere and chemical composition further (such as how Earth "naturally" shouldn't have an oxygen atmosphere but instead a nitrogen/carbon dioxide atmosphere but life came along and ruined it), which may then trigger further alterations.
In all, it would be several years work for a 2 dozen strong team of specialists to have a basic atmospheric planet that you can land on and admire a funny coloured bacteria-like stain on a rock. Once you get into macroscopic life, it adds entirely new levels of difficulty.
![[PS4] Lorenzo Waringos](https://d2aefvhu2f0gi9.cloudfront.net/data/avatars/m/234/234580.jpg?1612617334){kind=avatar}
