Just posting a couple of links I found about spaceflight history, Kerbal Space Program, and 3D printing…
First, here is a YouTube series that reimplements the early days of human spaceflight using Kerbal Space Program. https://www.youtube.com/watch?v=-mGUlv_dn-g&index=2&list=PLBhKowDYZ822XxTabtoYup81ZLsrgA4be
I have only watched the first few episodes so far, but I think they are great and the rest of the series in on my watch list.
Second, here is a blog post talking about how to export your Kerbal Space Program creations into the real world using a 3D printer (and some software of course) – https://www.matterhackers.com/articles/print-your-ships-from-kerbal-space-program