Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!mcsun!ukc!slxsys!ibmpcug!demon!news
From: printf@cix.compulink.co.uk (Ian Stirling)
Newsgroups: sci.space
Subject: Solar sails and Belt mining
Message-ID: <1991Jun16.125917.7326@demon.co.uk>
Date: 16 Jun 91 12:59:17 GMT
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Reply-To: Ian Stirling <printf@cix.compulink.co.uk>
Organization: Gated to News by demon.co.uk
Lines: 23

If you can make a workable solar sail how much more difficult is it
to make a large parabolic mirror for melting large boulder size
chunks of rock? Could you mine a asteroid my melting it and allowing
the vapour that comes off to condense on nearby cooled surfaces,using
a sort of fractional distilation to seperate the metals.Also could
you get higher temperatures than the surface of the sun by filtering
the incoming light at the mirror(diffraction grating ?)to leave only the
higher energy photons,this does not seem to violate any laws as you
are only able to use a small fraction of the incoming light to heat
the object but most of the light goes past at lower overall energy.

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