Re: cheap lunar gear & base (spin-off of superhero flight)

Bryan Derksen <bryan.derksen@[EMAIL PROTECTED]
> wrote:
> You're unlikely to get the bends from a 0.8-atmosphere drop in pressure.

> That's the equivalent of coming up from a dive of 26 feet depth. Digging

> around a bit, I found a website suggesting that divers don't need to 
> bother with decompression unless they go under 130 feet down.

It is not uncommon for pilots to go to pretty extreme altitudes with 
nothing but an oxygen mask. The only limit is when the air pressure is no 
longer enough to push sufficient oxygen into the blood when breathing 100%

O2. (The limit is actually slightly higher than this, because there are 
systems which give you a bit higher pressure in the lungs than outside, 
but it's not a big difference in the end.) These altitudes are attained 
pretty quickly and unless you've recently gone diving there are no 
problems with decompression.

> There'll be unpleasant ear-popping, perhaps, if your tele****ter is 
> switching air pressures instantaneously. Perhaps she should tele****t to 
> a mountaintop first in order to give her ears and sinuses a few seconds 
> to drain of excess air. Can she tele****t into mid-air higher than that?

From what I've read about explosive decompressions it sounds as though 
an immediate change is doable. Air leaves these cativies relatively 
easily, although making it a gradual change would be better.

Coming back could be worse. Air escapes a lot more easily than it returns.

When you have low pressure outside and high pressure inside, the excess 
just forces its way out. But when you have high pressure outside and low 
pressure inside, the outside pressure forces the channels closed.

Digressing slightly here... this can mean that you may have mild 
congestion that you don't discover until you return to the high pressure 
environment. I had this happen to me a couple of months ago. I had the 
beginnings of a cold but didn't think it would be a problem. Going up was 
fine. Coming back down I discovered that my ear no longer wanted to accept

incoming air, even with lots of encouragement. It was extremely painful 
although not quite debilitating, and it finally cleared overnight. This 
was with a pressure differential of only about 0.3 atmospheres.

It would be interesting to see Our Hero come urgently back from his secret

moonbase only to be taken down by a mild upper respiratory infection he 
didn't even realize he had yet.

> What would worry me most is carbon dioxide and monoxide buildup. Just 
> adding more O2 to the air doesn't get rid of that, and plants are very 
> slow. Make sure to bring some monitoring equipment with you to keep an 
> eye on that.

If your structure leaks then repleni****ng it with O2 will result in your 
CO2 level reaching some sort of equilibrium, with faster leaks leaving you

with less CO2. I don't know if this will be a reasonable way to deal with 
the situation, but if you can easily bring up air from Earth then it may 
well be the simplest solution. Getting too stuffy in your secret moonbase?

Just open the door a bit....

-- 
Michael Ash
Rogue Amoeba Software