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+--- Thread: Windows without mirrors (/showthread.php?tid=56)
Windows without mirrors - JoeStrout - 08-04-2015
Yeah, it doesn't make a lot of sense in most cases, but players are certainly going to experiment with having windows without mirrors on their hab modules:
![[Image: 8krEh.jpg]](http://i.snag.gy/8krEh.jpg)
...and when they do, we have to decide what light level to simulate inside.
Now in design mode, we don't have the light direction quite what it should be; it should be coming straight in from the side, but the harsh shadows make it difficult to work that way, so we've angled the light a bit here.
But once you actually build your colony, it's oriented perpendicular to the plane of the ecliptic, which means that the light will be coming in straight. So if you've got a torus, or a cylinder with inverted endcaps, those windows are seeing nothing but starlight.
But if you have a sphere or a cylinder with outward endcaps, then the windows do see some sunlight. Much of it would bounce right off, of course, given the low angle to the sun, but some of it would get in and bounce around inside (especially if the windows are diffuse, as I assume they would probably be).
This is where it gets really hand-wavy, though... how well lit is that? Just in terms of area, if you look at one of these spheres from the end (as when using them with a mirror), the windows are about 50% of the presented area. But from the side, the area presented is much smaller, more like 25%. So that's a 50% reduction or so.
Or you could look at it this way: with a mirror, 100% of the windows are receiving sunlight, but without it, only 50% of the windows are lit (and much of that is at an extremely low angle), so that also means 50% or less light getting inside. Waving frantically, I say we peg the amount of light you can get this way at 40%.
For a cylinder, the situation is much the same, except that if your endcaps aren't hemispheres, you're going to get proportionally less light as you flatten them. And of course we also need to take into account the length of the cylinder... even when you're using mirrors, it makes sense that the longer the cylinder, the less light (per unit area) you're getting from the same windows.
Finally, there's barbells. These ones are really complex. Each bell obviously faces away from the sun half the time, but when its facing the sun, whether it's shadowed or not depends on whether the number of bells is even or odd, and (if odd) how big the hub is. And of course even if you have a tiny hub and 3 bells, the sunlight is going to be going on and off at the same rate as your spin (e.g. every 15-30 seconds). If that doesn't drive your residents up a tree, I don't know what will!
(And in the mirrorless cylinder or sphere, though the light would be a constant amount, the angle of the light would cycle at the same rate... less annoying than cycles of light/darkness, but still pretty annoying I bet.)
RE: Windows without mirrors - JoeStrout - 08-05-2015
(08-04-2015, 10:36 AM)JoeStrout Wrote: Finally, there's barbells. These ones are really complex. Each bell obviously faces away from the sun half the time, but when its facing the sun, whether it's shadowed or not depends on whether the number of bells is even or odd, and (if odd) how big the hub is. And of course even if you have a tiny hub and 3 bells, the sunlight is going to be going on and off at the same rate as your spin (e.g. every 15-30 seconds). If that doesn't drive your residents up a tree, I don't know what will!
Actually it's worse than that, because if you have windows in your barbells, you also have secondary mirrors. These will shadow the barbells when they would be facing the sun. You'd get a little bit of off-angle light, and then pass into the shadow of the mirrors (dark except for starlight), and then back onto some off-angle light, and then pass into your own shadow (dark again).
Sheesh. We'll certainly need to program the residents to complain if you actually build a colony like this!
RE: Windows without mirrors - antred - 09-22-2015
To make things even more complicated
, what about the O'Neill type cylinders that bring in light not via the endcaps but through mirrors that shine the light on the cylinder's window panes?
RE: Windows without mirrors - Pye-rate - 09-22-2015
None of these windows pay Bill Gates a penny, that could be a problem.
RE: Windows without mirrors - JoeStrout - 09-22-2015
(09-22-2015, 09:13 AM)antred Wrote: To make things even more complicated
Yeah. Those are really complex, and only work if you don't have multiple decks... and we'd rather have multiple decks (don't have 'em yet, but they're definitely something we're thinking about).
So, this O'Neill-style window arrangement might be something we leave out, unless users are really clamoring for it.
RE: Windows without mirrors - antred - 09-22-2015
Aww, too bad. If I could choose a habitat type to live in, I'd pick a giant Island Three type colony every time.
Don't know if this still up to date, but in his book The High Frontier, O'Neill wrote that it is conceivable that a cylindrical habitat vessel could be up to 4 times as large as his Island Three design. That would basically make it about 32 km in diameter and 120 km in length. Now I know that such a cylinder would have to be way shorter to remain stable, so let's make it only 16 km long (at which point it basically may as well be an oversized Torus with an inner diameter of 0 meters). Sorry, getting carried away here, but imagine living in such a thing!
EDIT: One serious problem I see with such designs (or any other designs that have windows at the bottom of the simulated gravity well) is, how would one keep the window panes from getting covered up by dust particles and other dirt? I seem to recall reading a blog post by someone who suggested filling the window panes with water, but IMO that would still leave them susceptible to sedimentary deposition over time. Or maybe you'd have to build a fleet of window cleaner drones to give the window panes a good scrubbing every now and then.
RE: Windows without mirrors - JoeStrout - 09-22-2015
Yep, I think a fleet of window cleaners would be necessary.
And note that in O'Neill's design, the cylinders always came in pairs, joined at the ends. That's how he worked around the stability problem. And this is indeed a sensible design, even if the game doesn't currently support it. My older son has been bugging me about this for some time, so we probably will fix that eventually; it's just that the physics is a little thorny!
RE: Windows without mirrors - hanelyp - 09-23-2015
Still water over windows does nothing to help with sediment. Flowing water could be part of a cleaning system.