Tom Mueller, the founding propulsion engineer of SpaceX who designed the Merlin engine that powers the Falcon 9, once described his first meeting with Elon Musk. It was at a backyard barbecue in 2001. Mueller was building rocket engines in his garage as a hobby. Elon heard about the garage rockets through a mutual friend and showed up at the barbecue specifically to meet him. Mueller expected small talk. He expected a rich guy who thought rockets were cool and wanted to fund a hobby project. What he got was a 30 year old who started asking technical questions about turbopump design within the first 5 minutes of conversation. Not surface questions. Specific questions about injector patterns, combustion chamber pressure ratios, and propellant grain geometry that Mueller had never heard a non engineer ask. Mueller said later that the conversation lasted 3 hours. They stood in a backyard in Los Angeles while a barbecue went cold and a party continued without them. By the end of the conversation Elon had convinced Mueller to leave his job at TRW, one of the most prestigious aerospace companies in the world, to join a rocket company that had zero employees, zero rockets, and a founder who had made his money from the internet. The Merlin engine that Mueller went on to design in that partnership is the most reliable rocket engine in the world. It has launched over 300 times with a success rate that exceeds any engine in aerospace history. The Falcon 9, powered by 9 Merlin engines, is the most launched rocket on earth. The most successful rocket engine in history was conceived in a conversation between two men at a backyard barbecue. One had the physics. The other had the audacity. The barbecue went cold. The partnership changed aerospace. And the party that continued without them has no idea what it missed.