Frosted cones and other thoughts

--- In spacesettlers, "Ed Schonert" wrote:

> Even at 500 meter diameter with 30 psi design pressure a
> cylindrical vessel would need ~23" wall thickness for old aluminum
> alloy with 15000 psi working stress. Anyone know what allowable
> working stress we can use with that new aluminum-lithium alloy?

How about glass fibers? Glass made in the vacuum (anhydrous, but I
won't swear to the spelling) are supposed to be very strong, and
lunar regolith (and perhaps many NEO's) have a lot more silicon than
they do aluminum, iron, titanium, etc.

> Also noticed that going from sphere to cylinder shape DOUBLED
> wall thickness (for same diameter & internal design pressure).
> No wonder G.K.O'Neill mentioned staying with spherical shape for
> first colonies in his video tape.

What about tori?

> My big hope is to go with cylindrical shape/center light cone
> design using the Al-Li alloy with far higher than 15000 psi
> working stress.

I'm glad to hear you talking like this. We don't need to wait for
bucky nanotubes!

> Also consider circumferential cables

Perhaps made of glass fibers?

> in tension on outside of shell every few meters letting us half
> that required wall thickness.

> Hallelujah - Praise Spacesettlers ! ! ! Ed
S.

Xenophile (who is happy to use the bucky nanotubes once they become
available)