Re: Re : Lunar Solar Power Stations vs. The Glaser Proposal

Hop David wrote:
Henry Spencer wrote:
Consider a narrow belt around the equator, of width `w': its surface area
is `2 pi r w', but its projected area perpendicular to the Sun axis -- its
useful area for intercepting sunlight -- is `2 r w'. The same applies to
an interrupted belt (although if the interruptions get big, e.g. you just
have a few isolated patches of array, you have to think in terms of the
average over a full rotation). So yes, a factor of pi.

Landis had already cut the figure in half for the night side, so he was
talking about that half of the narrow belt lying on the day side.

That surface area is 'pi r w'. It's useful surface area remains '2 r w'
so the factor is pi/2, not pi.

Oops, was I accounting for the same factor twice? Hop David is
correct. Where I wrote "an additional factor of pi," it should
correctly have said:

The average power is less than the facte-on-to-sun power by a factor
of pi, which accounts for both the night and also the cosine loss.

--
Geoffrey A. Landis
http://www.sff.net/people/geoffrey.landis

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