Agreed! It's also worth highlighting the bit where he asks Elon Musk: https://youtu.be/cIQ36Kt7UVg?t=382 https://youtu.be/cIQ36Kt7UVg?t=382 I've internally

Agreed! It's also worth highlighting the bit where he asks Elon Musk: https://youtu.be/cIQ36Kt7UVg?t=382 https://youtu.be/cIQ36Kt7UVg?t=382 I've internally asked this question so many times, like, guys, shouldn't we maybe do an aerospike? Musk focused on the high combustion efficiency of traditional combustion chambers, combined with the high efficiency of having two stages, as the reason why they won out. Jettisoning irrelevant fuel-containing mass as you go is great for efficiency and as a bonus it makes it easy to put sea-level-optimized nozzles on the bottom stage and vacuum-optimized nozzles on the top stage.