I've been diving back into reading Leviathan Wakes, book 1 of The Expanse series of novels. One of the major settings in that novel (less so in later novels) is the asteroid/dwarf planet Ceres, which at the beginning of the novel was described as having a (near) human population of around 6 million residents and another million or so in transitory population. The Wikipedia article for actual Ceres puts its rough volume at 434 million cubic-kilometers, or a mean diameter of approximately 940 km. Now the usable internal volume is likely MUCH smaller than that (maybe as little as 100 meters cubed, 1M cubic-meters per person, or 7 trillion m^3 / 7,000 km^3 for 7M humans), but even an artificial body (like a Stellaris Habitat or other station) would be a bit larger in terms of enclosed volume versus usable internal volume (maybe 20-25% larger, 8,400-8,800 km^3, 25.4 km diameter sphere).
When looking at the Habitats in Stellaris, I was curious as to how large they would realistically be (this is trying to get my head around their size, not to specifically ask for any change in their costs or construction times). I've often estimated that a single Pop would be somewhere on the order of 250 million human analogues (e.g., 100 Pops on a planet would be equal to 25 billion humans). A basic Habitat is indicated as housing 4 Pops, or 1 billion humans by my estimation - around 143x as many humans as The Expanse's Ceres. Assuming a linear relationship, my 1M m^3 estimate per person extrapolated out only comes out to 1.23M km^3 or a diameter of "just" 132.9 km - Death Star 1 was stated to have a diameter of 160 km, with crew and passengers of only around 1.2 million, so I might have errored quite a bit smaller. Changing the internal volume to 1 km cubed per person (or a little more than half of the ratio of the Death Star 1) puts the enclosed volume for the Habitat at 1.23 billion km^3 or a diameter of 1,328.8 km (our Moon has a diameter of 3,474.8 km in comparison).
Now looking at the Stellaris Wiki, it puts the cost of a 4-Pop Habitat at 150 Influence and 1,500 Alloys, while a Starbase at Star Fortress level is either 2,050 alloys (if the costs for the tiers below are added in) or 1,250 alloys (if not). I'm not thinking those are intended to be comparable costs, but does anyone have any thoughts on how big they are and how large of a Pop-fraction they contain? What about Mining or Research stations?
When looking at the Habitats in Stellaris, I was curious as to how large they would realistically be (this is trying to get my head around their size, not to specifically ask for any change in their costs or construction times). I've often estimated that a single Pop would be somewhere on the order of 250 million human analogues (e.g., 100 Pops on a planet would be equal to 25 billion humans). A basic Habitat is indicated as housing 4 Pops, or 1 billion humans by my estimation - around 143x as many humans as The Expanse's Ceres. Assuming a linear relationship, my 1M m^3 estimate per person extrapolated out only comes out to 1.23M km^3 or a diameter of "just" 132.9 km - Death Star 1 was stated to have a diameter of 160 km, with crew and passengers of only around 1.2 million, so I might have errored quite a bit smaller. Changing the internal volume to 1 km cubed per person (or a little more than half of the ratio of the Death Star 1) puts the enclosed volume for the Habitat at 1.23 billion km^3 or a diameter of 1,328.8 km (our Moon has a diameter of 3,474.8 km in comparison).
Now looking at the Stellaris Wiki, it puts the cost of a 4-Pop Habitat at 150 Influence and 1,500 Alloys, while a Starbase at Star Fortress level is either 2,050 alloys (if the costs for the tiers below are added in) or 1,250 alloys (if not). I'm not thinking those are intended to be comparable costs, but does anyone have any thoughts on how big they are and how large of a Pop-fraction they contain? What about Mining or Research stations?
