Abstract: A method of regulating pressure within a first propellant tank of a rocket engine having a first propellant tank containing a first propellant and a second propellant tank containing a second propellant, and a regulator device for regulating pressure within the first tank, the regulator device comprising a gas generator and a heat exchanger co-operating with the gas generator so as to vaporize at least part of the first propellant prior to reintroducing it into the first tank (16), the gas generator and the heat exchanger both being fed with the first propellant by a single first motor-driven pump, while the gas generator is fed with the second propellant by a single second motor-driven pump, wherein the flow rate of the first motor-driven pump is controlled as a function of a first parameter, while the flow rate of the second motor-driven pump is controlled as a function of a second parameter.

Abstract: A method of designing a valve presenting an orifice of section that depends on the position of the valve member of the valve, which section can thus be controlled. The method includes determining a desired variation relationship for the flow section of the valve, which relationship defines a desired variation in the section as a function of time; setting a predetermined movement relationship for the valve member; and defining the shape of the fluid flow orifice in such a manner that, at each instant, if the valve member moves in compliance with the predetermined movement relationship, the flow section remains equal to the desired section. The method makes it possible to design a valve that is simple to control.

Abstract: A method of starting combustion of a space vehicle engine, the method comprising igniting a propellant tank heater (25); once the heater (25) has reached stable conditions, pressurizing a first tank (23) containing the first propellant and a second tank (24) containing a second propellant, and in parallel filling respectively a first igniter tank (13) with the first propellant in gaseous form and a second igniter tank (14) with the second propellant in gaseous form until ignition thresholds values of temperature (T13, T14) and of pressure (P13, P14) have been reached; and injecting the first and second propellants in gaseous form contained in the first and second igniter tanks (13 and 14) into an igniter (12) of the engine, so as to initiate combustion.

Abstract: A method of regulating pressure within a first propellant tank of a rocket engine having a first propellant tank containing a first propellant and a second propellant tank containing a second propellant, and a regulator device for regulating pressure within the first tank, the regulator device comprising a gas generator and a heat exchanger co-operating with the gas generator so as to vaporize at least part of the first propellant prior to reintroducing it into the first tank (16), the gas generator and the heat exchanger both being fed with the first propellant by a single first motor-driven pump, while the gas generator is fed with the second propellant by a single second motor-driven pump, wherein the flow rate of the first motor-driven pump is controlled as a function of a first parameter, while the flow rate of the second motor-driven pump is controlled as a function of a second parameter.

Abstract: A method of designing a valve presenting an orifice of section that depends on the position of the valve member of the valve, which section can thus be controlled. The method includes determining a desired variation relationship for the flow section of the valve, which relationship defines a desired variation in the section as a function of time; setting a predetermined movement relationship for the valve member; and defining the shape of the fluid flow orifice in such a manner that, at each instant, if the valve member moves in compliance with the predetermined movement relationship, the flow section remains equal to the desired section. The method makes it possible to design a valve that is simple to control.