Watch SpaceX launch 40 OneWeb internet satellites on Thursday

I invented 3D printed rocket engines.
I also invented entirely re-usable rockets not just the booster. How they work is the booster contains extra liquid fuel and oxidizer plus small solid fuel landing motors. After the second stage separates, the booster continues on to a parking Low Earth Orbit and waits. When the mission is done the upper stages dock back with the booster and all of it lands back on earth making the entire rocket re-usable. Elon does not have either of these. The solid fuel motors are throttled using waste gates that release combustion chamber pressures.