chimericoncogene wrote:My phrasing was unclear, but the Rosinante-type mirror is a smart mirror with thousands of independently motorized units, identical to the louvered system used on Island Three but non-rotating. Since it can have the same overall mirror area as Island Three, just over a bigger, non-rotating and hence maybe lighter support structure, I suspect it might end up lighter overall.
Your suspicions don't add up to me. Like, literally, have you done the math? Gerrard O'Neill was an engineer, and designed these things with an eye towards materials strengths and mass, and given that his smaller designs do in fact have mirror arrays that wrap around the entire structure, I would expect that the Island 3 and Model One use three mobile structures rather than a single static one for good reason. If the structure is an array of independently moving mirrors, then the structure gets heavier due to the required machinery for independent tracking. That's the trade-off for using independent tracking.
Plus you have to consider the effects of micro-meteor impacts over time on the structure. A lighter structure is also more fragile. So you could make a mirror array that is as light as a solar sail, but it will be easily punctured and torn. That means it isn't a practical method for lightening the structure. Meanwhile
Also, the Rosinante design would call for the mirrors to move far more than the O'Neill design in order to keep light going into the habitat rather than
on the opaique walls of the cylinder, especially given the RPMs the cylinder makes. That would seem like a lot more wasted energy and call for a higher maintenance cost overall than a set of three mirrors would (or any other subset of rotating mirror arrays).
As to whether adequate light dispersion can be achieved without "checkerboarding" the habitat if you fill in the basal end less, I think mirrors can be shaped (convex?) to spread the light a little - easier to do in microgravity.
Checkerboarding is a non-issue due to diffraction. The distance between the individual mirrors in the array and the colonists mean that the light will naturally spread out over a distance and make it all appear like one mirror rather than thousands of individual mirrors. So no checkerboarding will be apparent to the human eye.
Plus, you can take the window sections and replace them with a smaller width
lens instead, allowing you to upscale the size of the land strips while keeping the same amount of light coming in. The mirrors would have to focus the light onto a smaller area which in turn gets spread out again by the lens. The spread would further mask the appearance of checkerboarding. On the other hand, I don't know how feasible it is to do this once you consider the need to cool the lenses.
Eh. Some people like the city center, some people like the countryside. Why else are housing prices in city centers so high? Some people want to be close to where the action is. And given the high cost of habitat, and "historical" city centers being small, I suspect that colonies will be jam-packed more often than not (not in the late phases of course).
HA! Ha ha. Hahahahahahahahahaha.
That isn't how the real estate market works at all, dude. If you look at the actual economic status or income levels of people living in inner cities, you quickly find that rent prices can actually be a predictor of poverty, as counter-intuitive as it sounds. No, at least in the US the rich don't live in the inner city. They get as far as fucking possible from it as they can, as often as they can, while balancing that against the need to visit the city for business reasons.
There is an entire sub-field of sociology called Urban sociology that deals with this kind of thing. If you go back in time to the Medieval period, the rich and poor actually lived pretty close together in cities. Cities were structured around other things, like types of profession practiced in any given quarter, and the need for military defensiveness. However, there are two constants in city planning. First is the presence of a city center where trade and business are done. The other is that the richest and most powerful members of society often have multiple homes while the poor and middle class can afford only one. The rich didn't mind having homes close to the middle and lower classes in these cities because they wouldn't spend all year there anyway. Often, their real home was a manor, estate, or villa far away from the city (or even an actual castle depending on the time period) that was remote and rural. These enclaves of the rich persist into the present day, as does the pattern of rich people having a second home in the city for business reasons. We call these enclaves "
exurbs," to indicate that they are even farther away from the city center than a suburb, and every major city in the modern day has them if you know how to look for them. If you are in the United States, you can look at census data to find out how rich a given area is (the geographic data is organized by zip code, which you can then reference back to a map). The exurbs are often surprisingly far from major city centers and can be immediately identified by a very high average income. Double check these exurbs against Google Maps, and you find that they
look rich. Even if there aren't actual mansions among them, they are always clean, well kept, full of nature, big houses, big lots, lots of trees and other cultivated natural landscaping, and often when the people are visible you find they are white as slate (something census data will also tell you). I've driven through a few of them. I can't imagine how someone can afford to have a lake in their back yard, and yet that's a thing I have actually seen. And this isn't even the richest of the rich. You can't even get close to the mansions of the super rich. They won't let you.
So if the rich are actually averse to the inner city, why are housing prices so high? It has to do with economic activity and exploitation. Back to the topic of city structure, when the Americas were settled by the British, the cities took on a specific socioeconomic structure that is still somewhat visible in old cities like Boston and New York, and the patterns are reflected all over the country in different ways. The basic pattern looks like a bullseye. In the middle you still have the marketplace and place of business just like in European cities, and if there is any housing its often where the rich stay while on business. Think of Trump's "apartment" in the Trump Tower that literally has as much floor space as a mansion. But as soon as you move away from the city center, the next ring of the bullseye is full of the destitute, the poorest people in the city. As you go away from the city center, the people living there get progressively better and better off economically. Unlike in Europe, the colonists tended to self segregate along economic lines. The middle class didn't want to live next door to the poor, the poor didn't want to live near the outright homeless, and the rich didn't want to live near any of them (hence plantations in the old days and exurbs in the modern era). But everyone middle class and lower still needed jobs, and those jobs were concentrated in the city center. Now if you were destitute or poor, your only way of getting to your job was to walk, and the chances were your employer had little tolerance for lateness. So being close to your job was essential. Middle class residents could afford other forms of transportation, though, so they could afford to live farther out. Alternatively, some of the upper middle class actually did business out in the country side with the true upper class, so living at the edge of the city made sense. It also allowed you easier access to parks, recreation, and nature, so overall it was more desirable.
Fast forward to today and the same trends remain. A few innovations happened: industrial and transportation hubs appeared that few people want to live around, cars happened, and modern cities will have multiple specialized city centers rather than just one. But there is still one "main" city center often identified as "downtown" or the Inner City and is visually distinct because of the presence of skyscrapers. That's what most people are talking about when they think of the city, but that's not the whole city, and the vast majority of people don't live downtown. Poverty often clusters around the areas just outside of downtown or at the edge of downtown, as well as in industrial zones (though redlining and ghettos can't be forgotten in this discussion either). The middle class tends to gravitate to the suburbs because cars enable such sprawl; you can easily get to the city center for work and education, or away from the city for recreation. Plus there is less of a smog issue. Suburbs also tend to have parks, but in some cities the car also enables day trips outside the sprawl entirely to nature reserves (national parks and the like). Poor people also have cars, but the cost of maintenance encourages the use of public transportation, which is another reason why the city centers still have clusters of poverty around them. If your car breaks down, you have a backup plan that keeps you employed. But lastly, lets talk about rent.
Just because a house or apartment has a high price doesn't mean the people living in it are rich or even middle class. It means the land owner, who often lives in a fancy suburb or even an exurb, can charge a huge amount of rent from whoever
does live there. This is where the issue of economic exploitation rears its ugly head. Whenever you hear about people living from paycheck to paycheck, keep in mind that those people don't necessarily have shitty salaries. What matters is the costs of living. Some cities are famously expensive to live in for various reasons-- be it the price of goods or the price of rent and utilities, a person's economic status is relative not only to their income but also their expenses. A really expensive city like San Fransisco might have poor people making surprisingly high income, yet they are still poor because everything costs so much. And the price of living can have a knock on effect where you might think the solution is to move out of town to some place more affordable, but many people get trapped because they lack the ability to save up the money needed to move. You have to somehow save up money while paying for your basic needs, and not everyone living in the inner city can do both. So while some people might live in the inner city by choice, that's not everyone. It may not even be the majority of people. Some people might live there because that's where their family has always lived, and they never think to move even if it would have
mental health benefits.
So when you look at the housing prices for major city centers, or even the average income, keep in mind that those numbers have to be put in context. The average income has to be put into perspective of rent prices and other cost of living expenses, as well as the presense of outliers (i.e. the super wealthy assholes who spend half the year or more in a summer home far away from the city). The price of land in the inner city is a natural byproduct of being nearer to commerce. It also reflects patterns of economic exploitation such as white flight, redlining, and gentrification. This shit is complicated, and you can't simplify the high prices of housing in inner cities to demand alone.
Meanwhile, while we don't fully understand the connection between access to natural environments and good mental health, we
know the correlation exists. So why, then, is it desirable to have our space habitats emulate the unhealthy environment of the inner city-- to literally pack people into little boxes, as you cutely put it-- when its not that hard or much more expensive to instead emulate the more naturalistic environment of the suburb? You know that's what habitats of the rich are going to look like anyway.
I tend not to subscribe to the "air is expensive" idea. The life support and recycling system is expensive. But oxygen is literally everywhere (Ceres is icy, and it's got brine with ammonium compounds on the surface, and the moon is drowning in oxidized compounds), nitrogen should be uber-cheap in the Kuiper (or anywhere outside the snow line - antifreeze in the moons, remember), and you barely need millions of tonnes of the stuff (O2, N2, etc) to fill in an Island Three. My guess is that Island Three weighs billions of metric tonnes. Worry about shipping in enough industrial base to build Island Three before you start worrying about the air (which is way under 1% of total mass).
I said its not
free, not that its expensive. You still have to move it from place to place in the solar system, which isn't free. Oxidized compounds aren't the same thing as oxygen, you first have to chemically change them to be breathable atmosphere, and that isn't free. And once a habitat has filled its atmosphere to capacity, it needs to balance that atmosphere constantly with some sort of recycling system (like, say, actual plants recycling the CO2). You have to remember that it isn't free in the sense that you have to balance the production of CO2 and other unwanted gasses because you don't want to cause ecological problems in miniature, because you don't have the support systems of an entire planet to fall back on. Its for that reason that a space colony would likely do well to consider controls on industrial activity and possibly even population cap (well, it has to cap the population at some point anyway because of the limited room inside the ship). That's what I mean.
And regarding smells - heavy industry - and even light industries handling malodourous compounds will have to have their own basic life support circuits. It's not like Earth, where the atmosphere can dilute everything to relative harmlessness. It should not be particularly hard to duplicate the basics - since you've got a bigger life support circuit backing you up, you just import O2 and export scrubbed CO2 as needed.
You just admitted yourself that life support isn't cheap. Why add to the costs during the construction phase when proper economic planning can limit the problem to begin with? Why, for instance, should we be treating plastic as a disposable resource? Tell me one good thing that has come about because of that short-sighted attitude towards petrochemicals.
Sticking new cylinders on the end of old ones always seemed to me harder than building a space frame and then attaching new cylinders on the side, but I'm a layman and that's just me. Stability issues will exist with both approaches, and I think an argument can be made for needing some way to remove cylinders "stuck in the middle" too.
I'm not an expert, but wouldn't your approach cause problems with the habitat tumbling if you screw up the balance of rotating forces? I think your approach is generally better applied to large diameter toroid stations like the Stanford design than cylinders. In fact, expanding a Torus by attaching additional toroids is the classic way of enlarging such a colony, with limits.
I think the solution isn't to physically connect more than two cylinders at any one time, but simply to have them orbit within close enough distance to each other (whether in the Earth-Moon system or in the Earth-Sun Lagrange points) that if you need to visit your grandma on the Old Town habitat, you can just take a ride to the spaceport and fly out to meet her. It also satisfies the desire to have space travel play a role in your science fiction, too.
Regarding cultural differences, Formless, my first thought back when I first laid my eyes on a Bernal sphere illustration was "Suburbs? Seriously? What a waste of space. You could fit a hundred thousand people in there easy.".
You know, the funny thing is that O'Neil proposed that with some speculative advances in materials technology the Island III design could be scaled up to allow millions of people to live in one, perhaps hundreds of millions. Which would require quite a packed cityscape no matter how you design it. There is a reason he envisioned colonies as an opportunity to experiment in new forms of governance, we're talking literal nation states in space here. Zeon from Mobile Suit Gundam is right out of his playbook.
