There has been a discussion on the "Space Elevator" Yahoo Group recently
about the use of water as a radiation shield for space habitats, and in
conjuction with transparent solids, used for window material.
;-)X
> There has been a discussion on the "Space Elevator" Yahoo Group
> recently about the use of water as a radiation shield for space
> habitats, and in conjuction with transparent solids, used for window
> material.
>
> Any thoughts here, or on shielding and windows in general?
up so that it provides for heat distribution as well as shielding.
Of course, this assumes a cheap and plentiful source of water at your
construction site; otherwise, you should use something cheaper and more
plentiful, like leftover slag from regolith processing. You need a LOT
of whatever you choose for shielding, and really any mass will do, so
whatever's cheapest is probably best.
In one colony design that's been evolving in my head, there is no
shielding outside the pressure vessel, since I want a couple meters of
soil inside anyway (for growing trees, planting flag poles, etc.), and
that serves as fine sheilding. Ponds would probably have to be lined
with some sort of shielding material on bottom, otherwise people might
get too many rads from diving. But I like to imagine one big lake,
perhaps around the equator, where the water is deep enough that this
isn't a major issue -- and the bottom of the lake is transparent,
allowing for a glimpse of the Earth, Moon, Sun, and stars through the
waves.
Probably wouldn't work in real life, as things growing in the lake will
quickly render its bottom no longer transparent. But it sure does make
for a pretty mental image.
Cheers,
- Joe
Joe Strout -- joe@...
Strout Custom Solutions, LLC
http://www.innertransit.org/ice.ppt
is a paper that I did for ISDC2007 on ice as a structural material. Use
it as a structural material and the shielding is free.
Mitchell James
> But I like to imagine one big lake, perhaps around the equator,
> where the water is deep enough that this isn't a major issue -- and
> the bottom of the lake is transparent, allowing for a glimpse of the
> Earth, Moon, Sun, and stars through the waves.
>
> Probably wouldn't work in real life, as things growing in the lake
> will quickly render its bottom no longer transparent. But it sure
> does make for a pretty mental image.
probably be an easier job than what the Roomba has to deal with.
And you know the traditional Island Three, with those humongous
windows? Put the lakes over those. Edge them with beaches, and you
can have sailing, surfing, and swimming. Maybe even fishing.
> > But I like to imagine one big lake, perhaps around the equator,
> > where the water is deep enough that this isn't a major issue -- and
> > the bottom of the lake is transparent, allowing for a glimpse of the
> > Earth, Moon, Sun, and stars through the waves.
>
> Don't know why you couldn't have robot window cleaners. It would
> probably be an easier job than what the Roomba has to deal with.
entire lake, but I guess it's not out of the question. And it sure
would be a great tourist attraction.
> And you know the traditional Island Three, with those humongous
> windows? Put the lakes over those. Edge them with beaches, and you
> can have sailing, surfing, and swimming. Maybe even fishing.
That's a cool idea. I wonder how that much water would affect the
spectrum and intensity of sunlight? It'd probably still be fine, not
as bright as a bright day on Earth, but then, that's fine with me (I'm
always losing or breaking my sunglasses...).
Cheers,
- Joe
Joe Strout -- joe@...
Strout Custom Solutions, LLC
>> And you know the traditional Island Three, with those humongous
>> windows? Put the lakes over those. Edge them with beaches, and
>> you can have sailing, surfing, and swimming. Maybe even fishing.
> spectrum and intensity of sunlight? It'd probably still be fine,
> not as bright as a bright day on Earth, but then, that's fine with
> me (I'm always losing or breaking my sunglasses...).
I don't really know the answer to that, but the idea has come up
before. Surely somebody's done the calculations? And if water soaks
up too much sunlight, I guess you could always concentrate it.
>
>> But I like to imagine one big lake, perhaps around the equator,
>> where the water is deep enough that this isn't a major issue -- and
>> the bottom of the lake is transparent, allowing for a glimpse of the
>> Earth, Moon, Sun, and stars through the waves.
>>
>> Probably wouldn't work in real life, as things growing in the lake
>> will quickly render its bottom no longer transparent. But it sure
>> does make for a pretty mental image.
>
> Don't know why you couldn't have robot window cleaners. It would
> probably be an easier job than what the Roomba has to deal with.
>
> And you know the traditional Island Three, with those humongous
> windows? Put the lakes over those. Edge them with beaches, and you
> can have sailing, surfing, and swimming. Maybe even fishing.
hobby) that thrive on algae and gunk. Put them in your window aquarium
and you're set.
Except for the radiation at the window where you need them to clean.
Brian Dunbar
System Administrator
Liftport - The Space Elevator Company
brian.dunbar@...
aim: bdunbar1967
GMT -6
this email is: [ ] bloggable [x] ask first [ ] private
Meaningful Work or Death.
Any other form of existence doesn't interest me.
Hugh Macleod
> We stock our pond with fish (species name escapes me - it's my wife's
> hobby) that thrive on algae and gunk. Put them in your window
> aquarium and you're set.
> Except for the radiation at the window where you need them to clean.
Well, I thought about that with regard to whatever fish you put in such
a lake. Their radiation exposure would certainly be unacceptably high
by human standards, but I'm not sure it matters that much for fish --
their lifespans are (in general) much shorter, so they don't have as
much time to accumulate the rads; and we tend to be less concerned
about their general happiness anyway (witness the popularity of yanking
them out of their water by a sharp hook through the lip, and leaving
them to suffocate to death on the deck of a boat). As long as
three-eyed-fish don't wash up on the shore to scare the tourists, I
think we're OK.
In fact I wonder if such an environment would fairly quickly evolve
radiation-hardened fish.
Best,
- Joe
Joe Strout -- joe@...
Strout Custom Solutions, LLC
Depends on the water depth. Long wavelengths are
absorbed first, red disappears in a few inches of H2O.
With increasing depth, the spectrum propagated shifts
toward the UV range. In the oceans, 90% of photo
synthetic life is in the top 100 feet of water.
> Depends on the water depth. Long wavelengths are absorbed first,
> red disappears in a few inches of H2O.
> With increasing depth, the spectrum propagated shifts toward the
> UV range. In the oceans, 90% of photo synthetic life is in the
> top 100 feet of water.
blue light, and you could still get a sunburn.
OK maybe this isn't such a good idea.
Well, UV is readily absorbed by glass, so sunburn may
not be a problem. With 3 to 5 meter depth, the yellow
thru blue end of the spectrum would still propagate.
aluminum(oxide). We call it sapphire. With no other
elemental inclusions, you should get a very nice
spectrum transfer and LOTS of strength however,I have
no idea what the ionizing radiation resistance would
be. I expect major industrial manufacturing of clear
sapphire is possible, even to large, thick sheets.
Gary 7
Sapphire! I've speculated that it may be possible to vacuum vapor
deposit the stuff. Why not make the whole habitat out of it, and then
add a millimetre layer of plain old opaque aluminum to those parts you
don't want to see through?
It will probably be more cost effective to look at available sources of
raw materials and then pick structural elements based on what you have
instead of what you don't have. If as predicted half of the NEOs are
burnt out comet cores containing large amounts of dirty water then
structural elements become ice with embedded fibers spun from the dirty
part. I am sure that sometime in the distant future somebody will spend
money creating an all sapphire structure for the same reasons that some
people spend money on glitz now.
brought up on this list.
Mitchell James
The Wikipedia article on AL2O3 says it has been used
in hip replacement and has a melting point of 2054
degrees C. I haven't found the tensile strength yet,
but I vaguely recall it is quite high. I note one
reference that states it is five times stronger than
glass. Pretty tough stuff.
If we finally determine how to prevent bones and
muscles from deteriorating in free fall, we can then
make space colonies as non-rotating structures and
that opens up a whole new environment, such as hollow,
rocky asteroids with low tensile strength. Cheap
enough that small groups could settle such bodies,
since they wouldn't have to add structural strength,
etc. Just remove some material, air seal the rock and
set up house keeping. Then we'd have some really cool,
cheap alternatives to the space cities, that your
average malcontent could colonize. With several
million asteroids in the asteroid belt, we could have
every imaginable society, as well as space pirates.
How many stories could be written with this option?
--- Mitchell James
I don't want to build it out of sapphire for the sake of glitz or
bling, I want to build it out of sapphire because of sapphire's
wonderful properties and because of the fact that aluminum and oxygen
are fairly common. For instance, it has been suggested to build a
Stanford Torus out of one million tons of aluminum derived from lunar
regolith. Well, the regolith contains more oxygen than it does
aluminum, so if you could use both, you wouldn't have to mine as much,
which would save money. And that's even assuming you wanted to use a
million tons. If sapphire is so strong, tough, etc., you might want
to use 750,000 Kg or even 500,000 Kg.
> I don't want to build it out of sapphire for the sake of glitz or
> bling, I want to build it out of sapphire because of sapphire's
> wonderful properties and because of the fact that aluminum and oxygen
> are fairly common. For instance, it has been suggested to build a
> Stanford Torus out of one million tons of aluminum derived from lunar
> regolith. Well, the regolith contains more oxygen than it does
> aluminum, so if you could use both, you wouldn't have to mine as much,
> which would save money. And that's even assuming you wanted to use a
> million tons. If sapphire is so strong, tough, etc., you might want
> to use 750,000 Kg or even 500,000 Kg.
No, wait; it wasn't me, it was that Xenophile dumbutt, whoever he is.
Yeah. He's not nearly as smart as I am. ^_~