Aerostat habitats
Aerostat habitats are human settlements situated exclusively within the atmosphere of a planetary object. On the world of Sophia, they are located in its upper atmosphere, approximately fifty to sixty kilometers above its surface. Such an altitude is chosen because the temperatures and pressures present are relatively Earth-like, averting the extreme conditions found on the surface. The design of these habitats utilize large, balloon-like structures filled with oxygen. Since such a gas is less dense than Sophia's carbon dioxide-rich atmosphere, these habitats naturally float, and as a result drift throughout Sophia's atmospheric currents. They are modular, with interconnected units for living quarters, hydroponics, laboratories, and industrial facilities. The outer layer of these modules are made of durable-heat resistant materials that protect against the world's acidic clouds and solar radiation, most often sporting coatings of polyimide foams and aerogels with skeletal structures of titanium alloys or carbon fiber composites.
In terms of energy, most aerostat habitats exploit solar power as their primary source of energy due to being mostly situated above the dense, toxic atmosphere, thus exposed to sunlight. However, larger habitats that demand more power can also utilize compact nuclear reactors or other fuel sources as necessary. Due to the nature of Sophia's atmosphere, these settlements rely chiefly closed-loop life support systems that maximize water recycling and rationing of food from hydroponic (or import) stores. Navigation between aerostats across Sophia is done through special vehicles that transit within such a habitable layer, deliberately avoiding the sea of noxious clouds that lie below. However, for surface mining operations, tethers can be used that drop from this layer downward which can assist in the delivery of hardened drones and ground vehicles.
Industrially, aerostat habitats primarily concern themselves with the large-scale collection of sulfuric acids, alongside the mining of large deposits of desired surface metals such as iron, nickel, and other precious metals in addition to the filtration of trace gases such as nitrogen and argon. Power generation is a growing habitat industry as the efficiency of collecting solar power increases, especially through the use of photovoltaic materials. However, the collective industrial capacity of these aerostat habitats pale in comparison to greater mining ventures in areas with less risk such as Plateia, Vasati, or asteroid fields.