ETT is a pinwheel design that is grouped into branches of related engineering disciplines. Premise Do the Kerbals discover rocketry before winged flight? You decide. Both winged flight and rockets first options.  ETT also has an "End Game" so you can play the campaign game with a built in goal. I love to hear new ideas and don't be afraid to let me know if I have a part or two out of place. Listed on CKAN or Download at SpaceDock - May break saved games. (May 5, 202