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rcgldr
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True, but the total energy includes the acceleration of the fuel from within the rocket to out of the exhaust nozzle of the rocket engine. If you take the energy change of the spent fuel into account, then the total rate of increase in energy of rocket and fuel (both spent and expelled) are constant with a constant amount of power.K^2 said:No, the power that pushes the rocket traveling at considerable velocity may greatly exceed the power of the engine.
The point is that in the beginning, the engine works to accelerate both the rocket and the propellant it is carrying. Only the energy used to accelerate the rocket is useful at this point. The rest is stored in the propellant. Once the rocket builds up to considerable speed, that energy stored in the propellant helps you push the rocket.
As mentioned before the power is related to Force x (Vrocket - Vexhaust), and (Vrocket - Vexhaust) will be a constant regardless of the rockets speed, for any given throttle (and power output) setting.