eliminate the LOX pump, "oxygen rich, closed cycle"
No it does not eliminate the LO2 pump it shares the turbine with the fuel pump. In effect you eliminate the separate gas generator, but put the fast spinning, highly loaded turbines in a much more hostile environment.
In the Russian nomenclature it's the main chamber / Afterburner system.
But the real clever one was tapping some of the gases off the main chamber and driving the turbines with those.
That's called "gas tapoff" but was too easy for the US to pursue until Blue Origin came along.
Biting the hand that feeds IT
