[Jan 24, 2020] The Engineering Tech Tree is officially back under work.  Thank you @linuxgurugamer for fixing the YongeTech software I was using.  Also, shout out to @GrubbyZebra and all those who helped keep ETTR alive while I was away.   -----------------------------------------------------------------   ETT is a pinwheel design that is grouped into branches of related engineering disciplines. Premise Do the Kerbals discover rocketry before winged flight? You