Leonard Erickson wrote:
> On Mon, 14 Apr 2008 07:45:07 GMT, Bryan Derksen
> <bryan.derksen@[EMAIL PROTECTED]
> wrote:
>> If you use pure oxygen to fill the habitat you'll have much less than a
>> full atmosphere of pressure, so that'll help ease the stress on your
>> door too.
>
> No thanks. I'm old enough to remember the Apollo 1 fire.
The Apollo 1 fire happened not just because of a pure oxygen atmosphere,
but because they used a _16 psi_ pure oxygen atmosphere. They needed to
test the spacecraft's ability to hold pressure in a vacuum, but since
they were testing it at sea level they had to pump it up with
higher-than-sea-level pressure inside to do that. In space, pure oxygen
atmospheres are only around 3 psi. The lack of nitrogen as a buffer gas
would make fires a bit hotter but you wouldn't get an instant
all-consuming infero like Apollo 1 did.
> Besides,
> plants will do an okay job of air renewal once they've got reliable
> power.
It's actually a lot trickier than it seems to get this to work. Google
for "CELSS" (Controlled Ecological Life Sup****t System) to find work
that's been done on this area. Plants will certainly be nice to have
around, for psychological reasons if nothing else, but you're still
going to need to worry about CO2 scrubbers and bringing more oxygen up
from Earth over the long haul. When your ecosphere is only the size of a
small house it's got too little inertia to strike a balance easily.
> You want higher pressure for that as well as well as avoiding
> decompression problems.
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.
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?
Alternately, since mass is so cheap in this scenario, you can just
over-engineer everything to such a degree that holding a full atmosphere
of pressure isn't a major concern. :)
>> An airlock will probably be needed; if the super isn't super-strong he
>> won't be able to open the hatch against atmospheric pressure, and the
>> super needs to be able to get in and out without blowing all the air
and
>> killing the visitor in the process. This should be just a matter of
>> installing a second hatch and putting valves in them to allow pressures
>> to be equalized.
>
> Well, depending on difficulty of making the hatches, the multiple
> hatch solution might be good.
>
> And once it's airtight and has decent supply of air and is at a
> reasonable temp, the tele****ter can help with some things.
If the tele****ter is able to take the super as a passenger and is always
available when the super will need to get inside the base, it might be
best to not bother with hatches at all. Dig the cave in a vacuum, bring
in the tele****ter to familiarize her with the location, then seal the
entrance completely. If you want solar power make sure to leave a cable
running through the plug.
> Either way, hauling up enough pressure tanks for "just in case" will
> be a chore, but doable.
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.
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