A method is provided for using high concentrations of hydrogen peroxide to drive a turbine (20′) in a turbopump fed rocket engine (12′). The method includes the steps of: (a) receiving fuel into a fuel rich pre-burner (50); (b) receiving high concentrations of hydrogen peroxide into the pre-burner (50); (c) converting the fuel and hydrogen peroxide into a fuel rich gas; and (d) passing the fuel rich gas through a turbine (20′), thereby using high concentrations of hydrogen peroxide to drive the turbine. Thus, by utilizing a fuel rich pre-burner (50) that operates at a very low mixture ratio, the drive gas for a turbine (20′) can be maintained at moderate temperature levels.