How to build a PressuVessel?

WTF? Radiation, maybe, but then a few meters of water is
an excellent radiation shield and doesn't need anything like
that much glass, and last time I checked water is:

a) common
b) transparent

In fact its even capable of taking compressive loads if you
freeze it.

What gives? Have I missed something here?

Mr J R wrote:

> Mike,
>
> Yes, 40 feet. I have been away for some time and have
> not seen all the postings yet. Since mid 1980, I have
> been in various groups that have been looking at
> developing structures and habitats on the Moon. It
> was common to find very large items like this.
>
> Joe Russo
> OuterSpaceDevelopment Community: Read our story to
> learn about a man that is helping to make fiction into
> reality at
>
> --- tomexe wrote:
>
>>--- In spacesettlers@y..., "Combs, Mike"
>> wrote:
>>
>>>From: tomexe [mailto:tomexe@a...]
>>>
>>>
>>>the original
>>>Island 3 design called for windows almost 40 feet
>>>
>>thick
>>
>>>Is this right? Four feet I could almost buy, but
>>>
>>40 feet? I ask
>>because it
>>
>>>seems like I once went back to O'Neill's original
>>>
>>Physics Today
>>article
>>
>>>trying to find the thickness of the glass, and
>>>
>>couldn't find it.
>>
>>>
>>>Regards,
>>>
>>>Mike Combs
>>>
>>I was suprised too, In fact the first time I saw the
>>figures I misred
>>them and thought the windows were only 3m thick. But
>>the glass panes
>>are built up from 3m cubes of vitreous sillica
>>glass. They way Dyffed
>>Dyar wrote his page I thought that he was refering
>>to O'Neal when he
>>was discussing this construction. I got it from here
>>
>>
>>
> http://www.dyarstraights.com/msgundam/frontier.html#OpenType
>
>>But yes, 4 LAYERS of 3m square prisms, actually not
>>perfectly square
>>but slightly trapezoidal so as to form the curve,
>>like the bricks in
>>a Roman arch. It doesnt need that much glass for
>>pressure, that mass
>>is just for radiation and durablity over centuries.
>>Possibly also to
>>handle the weight of water laying on it. Either as a
>>resevour or just
>>from the accumulation of precipitation. Its a
>>enormous amount of
>>glass, but when you consider the low cost of energy
>>and transport up
>>there, not impossible. It would require a fairly
>>substantial
>>infrastruction of glass factories and mining
>>operations on the lunar
>>surface or in low lunar orbit. There is pleanty of
>>silica and
>>sunlight up there. And Ti to make the frames, chosen
>>for strength,
>>availablity and corosion resitance, not weight. You
>>could use steel,
>>there is just as much of it on the moon, but that
>>corrodes badly from
>>the atomic oxygen in the solar wind.
>>
>>
>>
>>
>>
>>
>

--
- Ian Woollard (ian.woollard@...)

"Is a planetary surface the right place for an expanding
technological civilization?"
- Gerard O'Neill