Just to add a bit of clarification: When Mueller was making rocket engines in his garage, he wasn't some random nobody. He was definitely the most accomplished

Just to add a bit of clarification: When Mueller was making rocket engines in his garage, he wasn't some random nobody. He was definitely the most accomplished and successful rocket engine designer outside Russia, and could make real claims about being the best still working engine designer on the planet. The reason he was tinkering on small engines in his garage instead of designing big engines for his employer, TRW, was that after designing the best American first stage engines (the TR-106 and TR-107), it became clear that it didn't matter that his engines were better, for political reasons it was impossible to kill the RS-25 program (also known as SSME, or Space Shuttle Main Engine), and therefore any future vehicle would use them instead, despite them being strictly worse for any use other than for the Space Shuttle. This was immensely demoralizing to him, and he was considering just quitting the industry and doing rockets as his hobby. Then Musk managed to convince him to work at SpaceX, for a much lower wage (and stock options, but the rational early valuation for rocket company stock is $0), mostly on the promise that at SpaceX, his engines would actually fly. The NASA program of record heavy lifter, SLS, is still using the designed-in-70's RS-25 now, 25 years later, and plans to toss 4 of the $40M engines into the ocean on every flight. SpaceX is what happens when you build rockets with actually modern technology, instead of all the components NASA is forced to use because some senator needed to maintain employment in his home district.