The Western Lines

July 17, 2008

Crack pottery and Reality

Filed under: Ralph Buttigieg — ralphbuttigieg @ 10:24 am
Illustration: Courtesy of UA Steward Observatory

The big issue of our time is Global Warming. At least thats what politicians tell us. Now, I will not get into any debate between the skeptics and the warmist here. I call myself a GW cynic, I accept the Earth has gotten warmer, although it seems to have stabilized over the last few years, but I’m cynical about the motivations of some of the promoters, especially politicians. However lets put that aside for now, the question is what if anything, do we do about it.

Emission trading is what is usually proposed. This would put a cap on the CO2 produced with heavy taxes on any extra CO2. In Australia the government recently released the Garnaut report which told us we have to have an Emission Trading Scheme, ETS, but it will be costly. It will cost us an extra $3 billion in tax, cause electricity and fuel prices to increase, be disruptive to business and lots of general unpleasantness.

Other alternatives have been proposed. One proposed by Professor Roger Angel from the University of Arizona is to build a giant sunshade at the Earth-Sun L1 point.

“The earlier ideas were for bigger, heavier structures that would have needed manufacture and launch from the moon, which is pretty futuristic,” Angel said. “I wanted to make the sunshade from small ‘flyers,’ small, light and extremely thin spacecraft that could be completely assembled and launched from Earth, in stacks of a million at a time. When they reached L1, they would be dealt off the stack into a cloud. There’s nothing to assemble in space.”

The lightweight flyers designed by Angel would be made of a transparent film pierced with small holes. Each flyer would be two feet in diameter, 1/5000 of an inch thick and weigh about a gram, the same as a large butterfly. It would use “MEMS” technology mirrors as tiny sails that tilt to hold the flyers position in the orbiting constellation. The flyer’s transparency and steering mechanism prevent it from being blown away by radiation pressure. Radiation pressure is the pressure from the sun’s light itself.

The total mass of all the fliers making up the space sunshade structure would be 20 million tons. At $10,000 a pound, conventional chemical rocket launch is prohibitively expensive. Angel proposes using a cheaper way developed by Sandia National Laboratories for electromagnetic space launches, which could bring cost down to as little as $20 a pound. …

Originally it seemed like a completely crackpot idea to me. Still does in fact. The sunshade would cost billions, Angel estimates an annual expenditure of $100 billion for 50 years would be needed. However how much will emission trading cost over the same period? Already our politicians intend to water down tough emission control plans because of their cost. The Space Sunshade would at least have the secondary benefit of massively reducing costs to space. Holidays on the Moon would be a spin off. I’m beginning to think ETS is the real crackpot idea.


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