[TML] Environmental domes

[shadow at shadowgard.com]

On 4 Sep 2007 at 14:35, Hans Henrik Rancke-Madsen wrote:

> An old problem of mine has cropped up again. The TU is littered with 
> crummy worlds that nevertheless have sizable populations. Some of them I 
> put into sealed caves, some of them I put into arcologies, but some of 
> them I like to put under environmental domes, preferrably domes that are 
> large enough to have agricultural fields and sculptured landscapes -- maybe
> even national parks -- beneath them. I'd like them to be a mile high and 
> cover an area the size of a... what's the American equivalent of a shire?

County? And even that is iffy as there are some counties in the less 
populous states that are bigger than some of the smaller states!

> My problem is that I have no idea what the maximum plausible size of such 
> a dome is at various tech levels. I've thought about finding out the size 
> of the domes we can build on Earth today and then increase the diameter by 
> some factor (2? 3? 5? 10?) per tech level, but googling 'environmental 
> dome' gives me about 2 million hits, the first score of which are camera 
> mounts and hothouses...
> 
> Anyone know what we can achieve today and have any opinions about what 
> should be possible at higher TLs?

Unless there's an atmosphere at the same pressure (or close) outside, 
large domes get unworkable due to pressure problems. It's not as bad 
as underwater domes, but it's still a problem.

You see, the pressure differential will be different at different 
altitudes. And the mass of the dome gets weird too.

Oddly, there have been discussions of enclosing an entire planet in a 
"shell" which while it requires tech we don't have is actually 
*easier* as far as stresses go, because all of the "dome" is at the 
same altitude.

--
Leonard Erickson (aka shadow)
shadow at shadowgard dot com