Abstract: An autogenous system for controlling pressurization of a propellant tank in a pressure-fed propulsion system. The system includes at least one micropump that pumps a high vapor pressure liquid propellant or a propellant with low temperature critical point from the propellant tank into an engine in which a small portion of the propellant is evaporated and heated. The micropump controls a pressurization rate of a flow of the propellant. A method of controlling pressurization of a propellant tank in such a system includes pressurizing a propellant tank containing a high vapor pressure liquid propellant or a propellant with low temperature critical point; controlling a flow of a small amount of the propellant from the propellant tank to a combustion chamber using at least one micropump; heating and vaporizing the propellant in a heat exchanger; and using the micropump to control the amount of propellant vaporized and heated, thereby controlling the pressurization rate.