space stations vs terresterial colonies

> From: dsw_s
> Don't forget that you have to dissipate that heat too: a heat enginer
> always has a source and a sink. How much do the cooling vanes mass?

I think we might be talking at cross purposes. In a space furnace, there is
no 'heat engine' as such that converts sunlight into electricity to heat the
furnace. The sunlight is directly focused upon a lump of slowly spinning
metal which then heats up to whatever tempreature desired. The mirror itself
never rises about a few hundred C any material reaches in direct sunlight;
and hence doesn't need cooling. When the process is finished you adjust the
focus and allow the refined metal to cool. A cooling system (and hence heavy
vanes) would only be required if you wanted to rapidly cool the material for
some reason.

Besides mass is largely irrelevent. It doesn't really matter if a refinery
ends up weighing a million tons - as long as it's in a stable orbit, doesn't
need to go anywhere, and has plenty of customers.

John

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