Abstract: A system for cooling a portion of a rocket engine with an inert compound and transferring the thermal energy from the inert compound to the propellants. The energy absorbed by the coolant is used also to power the turbines which powers the pumps that pump the fuel, the oxidizer, and the coolant. Additionally, the coolant, which is an inert compound, is used to separate the oxidizer and the fuel before the oxidizer and the fuel enter the combustion chamber eliminating the need for a complex inert turbo pump seal package. The systems which pump or comprise the coolant physically separate the propellants before the propellants enter the rocket engine. The coolant remains substantially unconsumed in this cycle.