Abstract: A cryogenic liquid storage system for a spacecraft comprising at least one liquid tank with an outer casing and an evacuated space arranged between the tank and the outer casing. The system further comprises a propellant management device made of material that is a good conductor of heat and that is cooled by a cryorefrigerator to localize the liquid inside the tank when in microgravity, a filler pipe situated in the portion of the tank that is at the bottom when the tank is on the ground, and that is surrounded by an evacuated insulating double wall and a purge pipe connecting the tank to the outer casing and presenting an internal length that is not less than half the diameter of the tank.

Abstract: The electrolytic ignitor comprises an injector constituting a first electrode, a second electrode that is electrically insulated from the injector and that extends downstream beyond the injector, and a distribution channel to deliver a first mono-propellant to a first mono-propellant injector device constituted by at least one injection hole opening out in the vicinity of the second electrode, and an electrical power supply circuit adapted to raise the second electrode to a potential lying in the range 50 V to 1000 V relative to the potential of the first electrode. The electrical power dissipated by ionic conduction in the free jet of the first mono-propellant is suitable for giving rise to spontaneous decomposition of the first mono-propellant and for producing combustion gas that ensures ignition of jets of a second mono-propellant coming from a main injector situated in the vicinity of the second electrode.

Abstract: The electrolytic ignitor comprises an injector constituting a first electrode and including a fuel injector device, an oxidizer injector device, and an electrolyte injector device. A second electrode electrically insulated from the injector extends downstream beyond the injector. An electrolyte distribution channel for delivering electrolyte in the form of free jets through the electrolyte injector device comprises at least one injection hole in the vicinity of the fuel injector device and the oxidizer injector device. An electrical power supply circuit is adapted to raise the second electrode to a potential in the range 50 V to 1000 V relative to the potential of the first electrode. The electrolyte injected through the injection hole is capable of causing ignition of a gaseous mixture in a combustion chamber of an ignitor torch suitable for incorporating in a main injector of a rocket engine.

Abstract: An emitter for an ion thruster. The emitter is a field-effect emitter for a field emission electric propulsion or colloid thruster. The field-effect emitter has a first and second portions defining an internal reservoir for supplying a liquid metal or a conducting ionic liquid and has a slit connecting the internal reservoir to an exit orifice.

Abstract: In a closed electron drift thruster, a magnetic circuit for creating a magnetic field in a main annular channel comprises at least one axial magnetic core surrounded by a first coil and an inner upstream pole piece forming a body of revolution, together with a plurality of outer magnetic cores surrounded by outer coils. The magnetic circuit further comprises an essentially radial outer first pole piece defining a concave inner peripheral surface and an essentially radial second pole piece defining a convex outer peripheral surface. The concave inner peripheral surface and the convex outer peripheral surface present respective adjusted profiles that are distinct from circular cylindrical surfaces so as to form between them a gap of varying width presenting zones of maximum value in register with the outer coils and zones of minimum value in between the outer coils so as to create a uniform radial magnetic field.

Abstract: In a closed electron drift thruster, a magnetic circuit for creating a magnetic field in a main annular channel comprises at least one axial magnetic core surrounded by a first coil and an inner upstream pole piece forming a body of revolution, together with a plurality of outer magnetic cores surrounded by outer coils. The magnetic circuit further comprises an essentially radial outer first pole piece defining a concave inner peripheral surface and an essentially radial second pole piece defining a convex outer peripheral surface. The concave inner peripheral surface and the convex outer peripheral surface present respective adjusted profiles that are distinct from circular cylindrical surfaces so as to form between them a gap of varying width presenting zones of maximum value in register with the outer coils and zones of minimum value in between the outer coils so as to create a uniform radial magnetic field.

Abstract: The electrolytic ignitor comprises an injector (2) constituting a first electrode and including a fuel injector device (26), an oxidizer injector device (27), and an electrolyte injector device (1), a second electrode (5) electrically insulated from the injector (2) by an insulator (4) and extending downstream beyond the injector (2), an electrolyte tank (12), a solenoid valve (11) interposed between the tank (12) and an electrolyte distribution channel (3) suitable for delivering electrolyte in the form of free jets through the electrolyte injector device constituted by at least one injection hole (1) situated in the vicinity of the fuel injector device (26) and the oxidizer injector device (27), and an electrical power supply circuit adapted to raise the second electrode (5) to a potential lying in the range 50 V to 1000 V relative to the potential of the first electrode.

Abstract: The electrolytic ignitor comprises an injector (2) constituting a first electrode, a second electrode (5) that is electrically insulated from the injector (2) by an insulator (4) and that extends downstream beyond the injector (2), a tank (12) for the first mono-propellant, a solenoid valve (11) interposed between the tank (12) and a distribution channel (3) serving to deliver the first mono-propellant to the first mono-propellant injector device constituted by at least one injection hole (1) opening out in the vicinity of the second electrode (5), and an electrical power supply circuit adapted to raise the second electrode (5) to a potential lying in the range 50 V to 1000 V relative to the potential of the first electrode (2).

Abstract: The invention relates to a field effect emitter for a field emission thruster or colloid thrusters, that comprises first and second revolution parts (110, 120) defining an inner tank (160) for supplying a conductive liquid metal or ionic liquid, and a circular slot (170) for communication between the inner tank (160) and an outlet opening (171). The first part (110) includes a polished outer face (111) and an inner face (112) made by precision-machining and having conical portions with a predetermined single slope of between 5 and 8°. The second part (120) includes an inner face (121) and an outer face (122) made by precision-machining and having conical portions with a predetermined single slope of between 5 and 8°.

Abstract: A cryogenic liquid storage system for a spacecraft comprising at least one liquid tank with an outer casing and an evacuated space arranged between the tank and the outer casing. The system further comprises a propellant management device made of material that is a good conductor of heat and that is cooled by a cryorefrigerator to localize the liquid inside the tank when in microgravity, a filler pipe situated in the portion of the tank that is at the bottom when the tank is on the ground, and that is surrounded by an evacuated insulating double wall and a purge pipe connecting the tank to the outer casing and presenting an internal length that is not less than half the diameter of the tank.

Abstract: The compressor-evaporator system for liquefied gas contained in a tank comprises, in addition to a deice for evaporation by heat exchange with a liquid and devices for conditioning and transferring gas to a pipeline, a motor-driven turbopump comprising a rotary assembly of high bending stiffness on a common shaft line, with at least one high pressure pump, a turbine, and a central electrical machine capable of being used in motor mode or in generator mode. The rotary assembly of the motor-driven turbopump is adapted to present a high speed of rotation, greater than 12,000 rpm, while remaining outside ranges for exciting critical speeds in rotation. All of the internal portions of the motor-driven turbopump are immersed in a cryogenic fluid that is the same as the liquefied gas contained in the tank. The internal cavities of the motor-driven turbopump that are under different thermodynamic conditions are separated by contactless dynamic seals.

Abstract: The compressor-evaporator system for liquefied gas contained in a tank comprises, in addition to a deice for evaporation by heat exchange with a liquid and devices for conditioning and transferring gas to a pipeline, a motor-driven turbopump comprising a rotary assembly of high bending stiffness on a common shaft line, with at least one high pressure pump, a turbine, and a central electrical machine capable of being used in motor mode or in generator mode. The rotary assembly of the motor-driven turbopump is adapted to present a high speed of rotation, greater than 12,000 rpm, while remaining outside ranges for exciting critical speeds in rotation. All of the internal portions of the motor-driven turbopump are immersed in a cryogenic fluid that is the same as the liquefied gas contained in the tank. The internal cavities of the motor-driven turbopump that are under different thermodynamic conditions are separated by contactless dynamic seals.

Abstract: The cryogenic rotary coupling comprises segments of a cryogenic line that are capable of turning relative to each other about a pivot axis of the rotary coupling. Radial retaining elements and axial retaining elements define the pivot axis of the rotary coupling. One of the segments comprises a vacuum-insulated double-walled female portion and the other segment comprises a vacuum-insulated double-walled male portion engaged at least in part in the female portion. A first sealing gasket is interposed between a free end of the male portion engaged in the female portion and one of the retaining means. A second sealing gasket is interposed between a free end of the female portion surrounding the male portion and the other one of the retaining elements. A heater device is disposed in the vicinity of the second gasket.

Abstract: The cryogenic rotary coupling comprises segments of a cryogenic line that are capable of turning relative to each other about a pivot axis of the rotary coupling. Radial retaining elements and axial retaining elements define the pivot axis of the rotary coupling. One of the segments comprises a vacuum-insulated double-walled female portion and the other segment comprises a vacuum-insulated double-walled male portion engaged at least in part in the female portion. A first sealing gasket is interposed between a free end of the male portion engaged in the female portion and one of the retaining means. A second sealing gasket is interposed between a free end of the female portion surrounding the male portion and the other one of the retaining elements. A heater device is disposed in the vicinity of the second gasket.

Abstract: The cryogenic propulsion module comprises a main cryogenic thruster (10), two attitude-controlling secondary thrusters (21, 22), tanks (31, 32, 33, 34) for feeding cryogenic propellants, a device for intermittently pressurizing the tanks (31, 32, 33, 34), and a device for initiating firing of the main cryogenic thruster (10) in intermittent manner while the tanks (31, 32, 33, 34) are intermittently pressurized. The device for intermittently pressurizing a tank (31, 32, 33, 34) comprises a heat exchange circuit associated with a heat accumulator (61, 62) and a device (71, 72) for putting a predetermined quantity of a propellant into circulation in the heat exchanger circuit. The module also comprises a device for heating the heat accumulator (61, 62) in the periods between two consecutive firings.

Abstract: The cryogenic propulsion module comprises a main cryogenic thruster (10), two attitude-controlling secondary thrusters (21, 22), tanks (31, 32, 33, 34) for feeding cryogenic propellants, a device for intermittently pressurizing the tanks (31, 32, 33, 34), and a device for initiating firing of the main cryogenic thruster (10) in intermittent manner while the tanks (31, 32, 33, 34) are intermittently pressurized. The device for intermittently pressurizing a tank (31, 32, 33, 34) comprises a heat exchange circuit associated with a heat accumulator (61, 62) and a device (71, 72) for putting a predetermined quantity of a propellant into circulation in the heat exchanger circuit. The module also comprises a device for heating the heat accumulator (61, 62) in the periods between two consecutive firings.

Abstract: The closed electron drift plasma thruster uses a magnetic circuit to create a magnetic field in a main annular channel for ionization and acceleration, said magnetic circuit comprises: an essentially radial first outer pole piece; a conical second outer pole piece; an essentially radial first inner pole piece; a conical second inner pole piece; a plurality of outer magnetic cores surrounded by outer coils to interconnect the first and second outer pole pieces; an axial magnetic core surrounded by a first inner coil and connected to the first inner pole piece; and a second inner coil placed upstream from the outer coils. The thruster also comprises a plurality of radial arms included in the magnetic circuit, and a structural base which is separate from the magnetic circuit and which serves, amongst other things, to cool the coils.

Abstract: The thruster comprises, on a common plate, a plurality of main annular ionization and acceleration channels having axes that are not parallel and that converge in the outlet direction of the channels. A magnetic circuit sets up a magnetic field in the annular channels. The thruster also has a hollow cathode, a device for regulating the ionizable gas feed rate to each annular channel, and a device for controlling the ion discharge acceleration current in the channels. The direction of the thrust vector of the thruster can be controlled without significantly increasing the mass of the thruster.

Abstract: The ion beam concentration apparatus for a plasma thruster having closed electron drift comprises:a) an essentially frustoconical flared magnetic pole piece (63) open at both ends and designed to be situated downstream from the outlet plane of a plasma thruster having an annular ionization and acceleration channel (1) and peripheral and central pole pieces (3, 4) disposed on either side of the annular channel (1) to produce an essentially radial magnetic field in an outlet plane (14) perpendicularly to the axis of the annular channel (1); andb) an additional peripheral magnetic circuit (60; 80) connecting the downstream end of the flared magnetic pole piece (63) to said peripheral pole piece (3), the flared magnetic pole piece (63) co-operating with the additional peripheral magnetic circuit (60; 80) and with the peripheral and central pole pieces (3, 4) to define the shape of the magnetic field downstream from the annular channel (1) in such a manner as to constrain the ion beam emitted by the annular channe

Abstract: A first satellite is placed practically directly by a launcher on a first final orbit. A second satellite is placed on the same launcher is initially transferred to a highly elliptical waiting orbit whose semi-major axis points to intercept the torus formed by the sphere of influence of the moon on its orbit, and then during a maneuver at the perigee of the highly elliptical orbit, the second satellite is transferred to lunar transfer orbit. Changes in the perigee altitude and the inclination of an intermediate orbit on which the second satellite is to be found are obtained mainly by gravitational reaction in the sphere of influence of the moon, and during a last maneuver, the second satellite is placed on a final orbit having orbital parameter values that are quite different from those of the orbital parameters of the first final orbit.