Hi Nick

You're absolutely right, of course, but to build the SE, Brad Edwards style, you need non-counterweighted climbers. To have an equal counterweight for cargo-carrying climbers you need to be importing something of equal weight back down to Earth - suggestions?

I'm all for importing from space and we sure need noble metals right now and in the decades ahead if fuel-cells are going to take off as predicted - unless the newer non-precious metal catalysts pull through.

Off the top of my head how about magnesium from the Moon? Hassle is that carbon will be the new wonder material rather than light metals...

Adam

BTW light metals and processed silicon make great lunar exports to haul on the Lunar SEs - the more the merrier to feed SSP construction. But first SSPs need to be shown to make money and that'll take more than just private bucks on something so speculative.