The Everyday Astronaut, Tim Dodd, interviews Elon Musk about the Merlin engine used in SpaceX's Falcon 9 rocket. They discuss the engine's design and development, including its simplicity, reliability, and reusability. Elon Musk explains the challenges they faced with the initial ablative design and how they moved to a regeneratively cooled design. They also discuss the pintle injector, which is a key component of the engine, and how it provides good mixing of fuel and oxygen despite its coarse interaction.
The conversation also touches on the history of the Merlin engine, including its early versions and the improvements made over time. Elon Musk notes that the Merlin 1D is a significant improvement over the initial design, with a higher thrust, efficiency, and ease of manufacture.
The interview concludes with a teaser for the next video, which will feature an in-depth look at the Raptor engine used in SpaceX's Starship.
Here are the key facts extracted from the text:
1. The Merlin engine is one of the most reliable rocket engines to date and is at the heart of SpaceX's current workhorse, the Falcon 9.
2. Elon Musk and his team were trying to minimize the probability of going bankrupt when they started out, so they aimed for the simplest possible pump-fed engine.
3. The first Merlin engine, Merlin 1A, had an ablative chamber, which was a mistake according to Elon Musk.
4. Ablative chambers are fundamentally against the concept of reusability and can lead to erosion issues at high pressures.
5. The Merlin 1C engine had a mold copper liner in the chamber with a plated, high-strength nickel cobalt jacket.
6. The nozzle of the Merlin 1C engine was made of spiral-wound steel tubes.
7. The spiral-wound design was expensive and painful to manufacture and had issues with the hot gas seal.
8. The Merlin 1D engine was a significant improvement, with a regenerative approach and a simpler design.
9. The Merlin 1D engine had a phase shut-off for the pintle injector, which served as the oxygen and fuel main valves.
10. The pintle injector is a single-element injector that uses a coaxial sheet of liquid oxygen and fuel to mix and combust.
11. The pintle injector is naturally stable and does not have issues with combustion instability.
12. The Merlin engine does not use deep throttling, but instead turns down the power given to the turbo pump.
13. The Raptor engine is much more complicated than the Merlin engine and has a more complex design.
14. Elon Musk and his team have made significant progress in engine design and development over the past 12 years.
15. The Everyday Astronaut has created a 1:100 scale metal model of the Falcon 9 rocket, which is available for purchase on their website.