Ah neat, that looks like an extension of the book he wrote. I get a bit worried when he dismisses chemical rockets for lifting the initial spool into space, an

Ah neat, that looks like an extension of the book he wrote. I get a bit worried when he dismisses chemical rockets for lifting the initial spool into space, and starts going on about electric drive... it seems like he should limit the number of technical revolutions required to make this work, if he wants this to succeed on a reasonable time scale...