Re: Solar concentration mirrors in the outer solar system

From: Alex Terrell (alexterrell_at_yahoo.com)
Date: 07/09/04 

Date: 9 Jul 2004 03:49:01 -0700

shermanlee1@hotmail.com (Johnny1A) wrote in message news:<b3030854.0406200919.592e74ca@posting.google.com>...
> Bryan Derksen <bryan.derksen@shaw-spamguard.ca> wrote in message news:<4rdad0hfr9k5blcnnfo8a7pf0524bctldp@4ax.com>...
> > On Sat, 19 Jun 2004 20:09:04 GMT, "Perplexed in Peoria"
> > <jimmenegay@sbcglobal.net> wrote:
> > >It takes a lot of energy to find and refine that aluminum and to form it
> > >into mirrors. Such an installation will have to pay for its own cost
> > >of construction in less than 10 years to be worth doing. So, if you
> > >can estimate the energy cost of construction, you can construct a
> > >graph showing how time to pay back construction energy increases with
> > >distance from the sun. The point where that line rises past 10 years
> > >or so represents the real economic "edge of sunlight". It may be farther
> > >out than 3AU, but I'll bet it is well inside the Oort cloud.
> >
> > Solar mirrors of this type would probably be extremely easy to move
> > around the solar system; they're basically giant solar sails. So how
> > about doing all the manufacturing deep in the inner solar system,
> > where the aluminium and energy are extremely abundant, and send the
> > finished mirrors sailing out to the Oort? They could be "paid for"
> > with Oort cloud resources such as long-baseline astronomical
> > observations, volatiles, living space, etc. - whatever it is that
> > habitats and/or ships are out there for in the first place. There's no
> > need for complete material self-sufficiency as long as they're
> > _economically_ self-sufficient.
>
> There's also the safety element, of course. It strikes me that a
> couple of compact, shieldable fission/fusion reactors might be a
> _safer_ source of energy than a fragile film of aluminum. OTOH, the
> fragile film of aluminum has fewer components and a very reliable
> ultimate source of energy.
>
> It's the sort of tradeoff that we'd need experience to make, since
> it's a judgement call.
>
> Shermanlee

If you have redundant cabling, it's difficult to see what could damage
your mirror. Meteorites would just pass through it, so after a few
centuries it might be degraded, but not destroyed.