Frosted cones and other thoughts

Frosted cones and other thoughts

But 1st, -an ininteresting URL..

Nanotubes at 1/10 the cost
http://www.evworld.com/databases/shownews.cfm?pageid=news230702-01

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According to "High frontier" [ -P. 64 2nd Ed., -P. 37 3rd Ed.]

Island III was designed to be 4 Mi. in diameter and 20 Mi long. with a
'land' area of 500 sq. miles.

[He's including the windows and both of the cylinders.]
-The actual land area in each cylinder would be about 120 Sq. miles.

3 mirrors 20 miles long [actually they should be about 28.3 mi. long
to give a noonday sun along the full length] X 2 miles wide at a
45 degr. angle present an 'effective' solar capture surface of 60 Sq.
mi. [or 85 Sq. mi, if 28.3] spread over 120 Sq. mi. of land.
[equates to 0.5 [ 0.7]available solar intensity]

An end cap with a diam. of 4 mi has a capture surface of
(Pi x r square) = 12.56 Sq. Mi. [at 1.0 intensity would still be worth
only 25 [18] Sq. miles of mirror].

This would require an additional focusing disc reflector large enough
to make up the difference. [say, slightly over 10 mi. in Dia. with an
id. of somewhat more than 4 mi.]

But then you wouldn't want a cone base of much over 2 mi. else too
much interior volume is taken up; plus the effect on the weather is
imponderable at any substantial diameter.

If you are willing to increase the disk size sufficiently you may be
able to decrease the cone base diameter to something livable...

P.S.

Have you thought of making your non-rotating protective shield
large enough to enclose the mirrors at full [45 degr.]extension?

Of course for economy's sake you would want to rotate the cylinder
120 degr. at midlength so as to provide 6 mirrors only 10 [14] mi.
in length. thus allowing a non-rotating cylinder shield of about 15
[19] mi. [or so] in Diameter.

[The back half could be tapered at 45 degr. to reduce mass.]

More expensive than you had in mind, but it might be worth it in the
long run.

P.P.S.

I haven't thought this through, and considering the math, probably
never will, -but, if the mirrors were halved lengthwise, separated,
and set at an angle to each other, couldn't the windows be reduced
nearly by half in width, thus increasing both protection and land
area? [-or perhaps a concave mirror?]

-Or would this mean excessive heat where the beams cross thru the
window?

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