Superconductors and mass drivers (and other electric guns)

For example, a bunch of stuff about how mass drivers
cannot propel complicated payloads, they are too "delicate". The author does not seem to understand that the primary reason for the mass driver is to get raw materials to L-4/5. It seems to be true that many more space advocates are aware of the general principle of mass drivers than are aware of the specific details of the High Frontier plan. I just got through spending a couple of weeks arguing with somebody on a newsgroup about lunar industrialization. To this person, it was obvious that all ore refining and manufacturing would be done on the moon. I told him some of the details of the NASA Summer study, where it was recommended that all refining/manufacturing take place in HEO, and that manufacturing on the moon be deferred until it was time to expand lunar facilities (in other words, lunar manufacturing only makes sense for products whose end use is on the lunar surface). To this person, this was utter nonsense, since, as everyone knows, it will be much more expensive to refine or manufacture in space than on the lunar surface. He was dismissive of the problem of limited solar power access on the lunar surface, and was certain that rotating for gravity would make everything more difficult and expensive. He kept repeating that if the refineries/manufacturing facilities were in HEO, then they would be separated from their ore supply by a 3 km/sec delta-V (it's actually a bit less than that). I had to keep repeating that unless the end use of the finished products was on the lunar surface, one would have to pay that lift cost in either case. Then he and another person started arguing with me about paying to lift the slag instead of finished products only. They seemed dismissive of the usefulness of slag in HEO for shielding and soil substrate for crop growing. I'm still convinced it was simply an example of that planetary chauvinism Asimov warned us about. It basically boiled down to the fact that refineries and factories on the moon fit inside of their imaginations easily, but same in HEO seemed somehow wrong or nonsensical. Like in the article being discussed above, there seemed to be a perception than mass drivers much longer and bigger in diameter for the launching of finished products somehow made more sense than the much shorter and smaller-diameter one O'Neill proposed for the launching of ore only, since it enables one to do all the ore reduction and manufacturing on a planetary surface, which everybody knows will be easier than trying to do it in space. I'm convinced that the kind of mass driver O'Neill proposed would be so much more economical to build and operate than one sized for finished products that it could lift the ore (slag included) for less cost than the latter could lift manufactured products. A limiteless supply of cheap oxygen (oxidizer) at L-4/5
would completely change the economics of space travel. An excellent and highly significant point.