Nice article.

I assume this has been submitted in response to the wikipedia article submitted here:

https://news.ycombinator.com/item?id=8577596

You'd probably like "The InterPlanetary Superhighway and the Origins Program" [1]. It goes into more depth.

The article "Next Exit 0.5 Kilometers" [2] is a nice general audience overview of this stuff.

[1] http://www.gg.caltech.edu/~mwl/publications/papers/IPSAndOri...

[2] http://resolver.caltech.edu/CaltechES:65.4.Exit