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Missile Defense

Technology has always found its greatest consumer in a nation's war and defense efforts. Since the last attempts at a "Star Wars" defense system, has technology changed considerably enough to make the latest Missile Defense initiatives more successful? Can such an application of science be successful? Is a militarized space inevitable, necessary or impossible?

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rshow55 - 02:01pm Jun 30, 2003 EST (# 12765 of 12770)
Can we do a better job of finding truth? YES. Click "rshow55" for some things Lchic and I have done and worked for on this thread.

fredmoore's 12758 http://forums.nytimes.com/webin/WebX?8@13.lAIobW4Almp.1317985@.f28e622/14429 includes this:

There are many problems with the solar collection array but why go past the one about the salt and dust continually reducing the efficiency? The cleaning schedule would require most of your output.

Support is a major fraction of the cost of solar arrays - and cleanliness and durability are major issues. I think that the cost per area would be lower on the equatorial seas, after a little development, than anywhere else on earth, and that cleanliness and durability could be the highest practically available on earth as well.

The basic points could be checked quickly - which would be another reason, in addition to assessment of ecological concerns, to make and float a 1 km/10 km prototype - even if it didn't have working photocells - and see what happened.

Most active duty naval officers could get that job done efficiently.

For flotation, I'd suggest using commercially available polyethylene bubble wrap - it comes in big 2 meter rolls, with about 1 cm bubbles, and could be made to any other specification. I'd choose fairly heavy duty bubble wrap - and use it with the bubbles down. Sections of bubble wrap material could be taped together for assembly.

On the flat polytheylene surface opposite the bubbles I'd glue glass plates - if this was just a first prototype - or photocells in glass plate form. Scaling isn't critical, but I'd choose a hexagonal array of 1 mm thick glass plates, each cut into regular hexagon shape - about 10 cm on a side (20 cm across - 33 plates/square meter), with just enough space between the plates for assembly flexibility to accomodate wave motion. There should be enough perforations of the polyethylene surface between the plates to permit rainwater drainage at the maximum downpour rate to be expected (about 7 cm/hour ).

If I was just using glass plates, as a prototype - it would make sense to paint or treat the bottom surface of the plates so it had light absorbtion and reflection properties similar to what would be expected with photocells.

Such a prototype array. using only glass plates rather than photocells, might cost about 1$/square meter - 10 million dollars for a 1 km/10 km array - but floating it, watching it, and learning to handle it would answer a lot of questions about array feasibility.

In large scale production, costs below $1/square meter would be expected for this basic support geometry. The photocell units - on plates of the geometry described - would be mass produced in very large numbers (to supply the whole world's energy needs, more than 10^12 would be needed) - and manufacturing engineering could be expected to get efficient photocells from both a cost and an electrical conversion point of view - and costs of photocells, with electrical connections - of the order of 2$/meter squared seem reasonable.

My guess is that the plates would stay clean - and stable. Dust on the equatorial seas is very sparse - and so is salt spray. It rains- and rain would clean the plates.

A typhoon would break up such an assembly. But the assembly would tolerate waves with radii of curvature of two meters or greater indefinitely, I believe - and equatorial seas are generally far, far smoother than that.

I believe that a mean life of decades for collectors on equatorial seas would be achievable for units of the order of simplicity described here.

rshow55 - 04:42pm Jun 30, 2003 EST (# 12766 of 12770)
Can we do a better job of finding truth? YES. Click "rshow55" for some things Lchic and I have done and worked for on this thread.

gisterme 2136-7 http://forums.nytimes.com/webin/WebX?8@13.lAIobW4Almp.1317985@.f28e622/2652 includes great questions about the equatorial solar energy proposal I've made. I responded to some of those points in 12763-12764 http://forums.nytimes.com/webin/WebX?8@13.lAIobW4Almp.1317985@.f28e622/14434 and respond to the rest of them below.

gisterme: " What would happen to an array when a typhoon hit a collector?

If a collector was hit directly by a typhoon it would be destroyed. That's another good reason for having many collectors (thousands) rather than just one. My impression is that even moderately heavy weather at the equator is a rare event - but somebody could estimate the actuarial risks well, and should in due course. I do know that tropical storms tend to start in the tropics - around 20 degrees latitude, north and south of the equator. Because the earth tilts with respect to the plane of its orbit around the sun, the point of maximum illumination, and longest days, varies from plus or minus 20 degrees latitude between summer and winter. If collectors could be towed so that they were near the point of maximum illumination - the convective center of the earth - they'd be in very calm sea - "doldrums" all the time. In sailing days, it used to be a big deal to cross the equator - because it was hard to do. There is very little wind - and often not much rain. There are waves, but the big ones have generally travelled thousands of miles - and the collector assembly can be designed (and tested) for very long or effectively infinite life at the wave loadings to be expected.

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