In article .com,
wrote:
I know plastic at exremely low temperatures is extremely brittle.

Only if you use the wrong plastic. Some plastics behave very well at
cryogenic temperatures...

Besides, this is irrelevant. Any structure meant for human habitation
will *not* reach cryogenic temperatures anywhere. There'll be insulation
on the outside -- you want the insulation external, because that lets you
use MLI, which is superb insulation but works only in vacuum -- and the
structural shell will never be much colder than room temperature.

Space is *not* cold. It has no temperature. The average temperature of
an object in Earth orbit, assuming no special measures are taken, is
rather Earth-like. After all, a nice warm Earth fills half the sky.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |