True. However, we spent all our time playing with ultra expensive high efficiency hydrogen fueled engines and abandoned our kerosene (1st stage) engines. The Russians kept working hard on them knowing dense kerosene fuel engines are really important for 1st stage use. Their metallurgy and technology for this type jumped way ahead while we sat on our laurels, bragging about our RS-25 SSME and how our awesome F-1 was so yesterday, though we couldn't replicate its performance without a decade of development. And to think it was done in just a few years with a slide rule and a regular pencil...not even a mechanical one.

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I love sanding.