Re: Once again - trying to get this to work
A total of about 1366 watts/sq.meter of solar radiation (all wavelengths) reaches earth from the sun. Only a fraction (~0.18) penetrates the atmosphere to ground level in the midwest USA. This means that a sunlight collector orbiting earth only has to be ~0.18 times the size of the greenhouse acreage. The lack of atmosphere is very favorable for greenhouses as far out as Mars or even the asteroid belt. Beyond that we are looking at some seriously large collectors. As you can see below:
<image src="http://www.geocities.com/womplex_oo1/SpaceSolarCollector.jpg">;
A sunlight collector for a 10,000-person greenhouse orbiting Pluto would have to be 68.8 kilometers in diameter.