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Does anyone know what the dry mass and mass ratio of the Falcon 9v1.1 Full Thrust Stage 1 is? The best info I've been able to find was by taking the specified burn time and multiplying it by the mass flow (which in turn was obtained by combining thrust specific fuel consumption and known thrust), but since I'm assuming there is first stage downthrottling at some point before MECO, that's not a sure thing.

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  • $\begingroup$ SpaceX used to turn off 2 engines later during ascent versus throttling, though they could throttle, giving them fine grained control. There is a 85% to 100% change in thrust with no appreciable mass change, per everything I have read. Question is what 85% means. $\endgroup$
    – geoffc
    Jan 29 '16 at 20:18
  • $\begingroup$ Yeah, we can speculate about how much thrust changes, but that's nonlinear. This page gives the specs for 9v1.1 before the FT upgrade (spaceflight101.com/spacerockets/falcon-9-v1-1-f9r), and the FT upgrade is supposedly "33% better performance" but who knows what that means. $\endgroup$ Jan 29 '16 at 20:20

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