The scrap-hull vs. the ET-salvage dream (was The scrap-hull vs. the

> It makes so much sense to get a second use out of [a
> pressure vessel] that is already going to orbit anyhow.

If we were building a space station, or a mass driver engine, I would agree
with you. But how do we transform the shipyard steel hull of a BDB into
lightweight SPS girders?

It wouldn't be useful without putting a very large steel mill and rysk
facility into orbit. That will not be cheap to launch or run. Yes a lunar
mine will also require similar elements, but on the moon we can take
advantage of local materials for radiation protection and thermal
insulation, and of our masive experience in operating such facilities in the
presense of gravity, and the nature of the (pre ground) material we will be
processsing. For those reasons I do not believe BDBs will be competative
against lunar mining costs or RLVs in SPS construction.