Quix about:
Raptor Engine Combustion Instability: How Spacex Solved the Full-flow Staged ComDeep technical analysis of SpaceX Raptor engine combustion dynamics, including pressure oscillation mitigation and injector design optimization.
OPEN
251 views
SpaceX chose methane for Raptor's full-flow staged combustion cycle. Could the same engine architecture work with hydrogen fuel to achieve higher specific impulse?
Additional Context
Hydrogen offers 450s specific impulse vs 330s for methane, but creates severe challenges: hydrogen embrittlement of metals, extremely low density requiring huge tanks, and higher turbopump speeds. The oxygen-rich preburner would be even more aggressive with hydrogen. Would the performance gains justify the engineering complexity?
Asked by:
Tom Mueller•Propulsion Engineer, Former SpaceX CTO
Tom Mueller•Propulsion Engineer, Former SpaceX CTOResponses (1)
Please sign in to respond to this quix
TM
Tom Mueller
•Propulsion Engineer, Former SpaceX CTOHydrogen FFSC is theoretically possible but practically nightmarish. The hydrogen embrittlement would destroy the oxygen-rich preburner components within hours. You'd need completely different materials - probably ceramic matrix composites. The turbopump speeds would increase to 80, 000+ RPM due to hydrogen's low density. Soviet attempts at hydrogen FFSC failed catastrophically. The 120s Isp advantage doesn't justify the 10x complexity increase.