@bonzoesc Reminds me of a time when I half-jokingly critiqued the phrase āitās not rocket scienceā to mean āitās not complexā. I argued rocket science was really pretty simple (TL;DR version: āconservation of momentumā) and the really hard part was rocket engineering (finding ways to use that concept that didnāt explode, incinerate the crew, or poison half the planet on the way up). Someone brought up Tsiolkovskiās rocket equation as a counterexample; itās a first principle thatās not immediately visible from conservation of momentum (though of course itās part of the derivation of the equation). Ok, fair, but as KSP enthusiasts can attest to: getting a usable spacecraft within the constraints of the rocket equation takes a lot of rocket engineering as well.