SPS vs LSP - Manufacturing

Greetings Mike, Here is my reply to the advantages/disadvantages of manufacturing by location/method. You are quite correct that HEO is very accessible and you could get a lot done there. The Space station has proven a lot of these details already. Where my concerns about this approach start is how similiar it is to traditional manufacturing especially in the larger scale and with very crude raw materials (ie moon dust). In the early stages at HEO I would imagine that all of the equipment would have to be premade and modular limiting expansion and maintenenceof themore complex parts. Contrast this with a gritty assembly line like turn of the century steel mills where the least cost and fastest production methods are being used. I hope to make a significant amount of the equipment and facilities from materialson the moon. Only the items like electronics, valves, guages, etcwhich are hard to make would be requested from Earth. The second advantage I can see on the moon is no issues with weightlessness or rotation. You can have a mimic setup in a warehouse on Earth down to the last detail.This allows elaborate analysis of virtures and troubleshooting.It would be a majoraccomplishment to make anything off the earth. To do it in orbit would be that much more of an accomplishment. Even if it is easy, I have a lot of trouble conceptualizing it. Toget big we are talking about the processing of tens tons of material on an hourly basis. If it turns out that the best way to refine silicon is to have an immense tank full of anothite and hydrogen gas at a thousand degrees then you can do this fairly easy on the moon. I'm hesitant to say that it is easy at all in orbit and you might have to spend a lot on building the enclosure. Everytime you move something big you have to rebalance the center of gravity and vibrations might be really hard to damp down. Lastly HEO only works well if you already have an established mass driver delivering material from the moon. You may turn out to be entirely correct that once the mass drive is in place on the moon that everything shifts to something in orbit at HEO, GSO (GEO), orany of the Lagrange orbits. Then we are back to O'Neills vision of manfacturing in space with a basis of support from the moon that costs about the same as landing a whole bunch of equipment in the origional vision. I tend to favor exchanging the up front cost for longer development times and more infrastructure. Cheers, Thor