Abstract: A solid propellant auxiliary booster intended to be attached to the main body of a launcher comprises a cylindrical body extending in a longitudinal direction between a rear face in communication with a nozzle and a front face formed by a conical structure connected to the cylindrical body of the booster. The cylindrical body delimits a first internal volume and the conical structure of the front face delimits a second internal volume. The auxiliary booster contains a solid propellant charge. The first internal volume of the cylindrical body communicates with the second internal volume of the conical structure. The solid propellant charge is present both in the first and second internal volumes.

Abstract: A modulation device for modulating a gas ejection section, the device being for placing in a nozzle upstream from the throat of the nozzle, the modulation device including a plug having a downstream end forming a member for partially obstructing the nozzle throat; and a plug guide having an internal housing in which the upstream end of the plug is present. The upstream end of the plug is suitable for sliding in the internal housing of the plug guide between a first position in which the upstream end of the plug is present in an upstream portion of the internal housing, and a second position in which the upstream end is present in a downstream portion of the internal housing. The upstream end of the plug is held in the first position by at least one retaining element for breaking under the effect of heat.

Abstract: A method of fabricating an opto-pyrotechnic initiator, includes a) forming a body having a cavity in which a pyrotechnic charge is to be received, the body also having an internal passage extending between the cavity containing the pyrotechnic charge and an inlet opening out in an outside face of the body; b) placing a first portion of an optical fiber in the internal passage of the body, with a second portion of the optical fiber extending beyond the inlet of the body, and a glass preform being interposed between the optical fiber and the inlet of the body; and c) applying heat treatment to the glass preform to raise the glass preform to a temperature higher than the melting point of the glass preform so as to form a hermetic sealing element made of glass between the optical fiber and the inlet of the body.

Abstract: A modulator device for modulating a gas ejection section, which device is for placing in a nozzle upstream from the throat of the nozzle and includes a plunger. The plunger has both a proximal portion connected to a control guide and also a distal portion in the form of a body of revolution, the plunger being movable between a retracted position and an extended position. The plunger presents, in its distal portion, a first section of concave shape and a second section of concave shape situated downstream from the first section.

Abstract: A method of fabricating an opto-pyrotechnic initiator, includes a) forming a body having a cavity in which a pyrotechnic charge is to be received, the body also having an internal passage extending between the cavity containing the pyrotechnic charge and an inlet opening out in an outside face of the body; b) placing a first portion of an optical fiber in the internal passage of the body, with a second portion of the optical fiber extending beyond the inlet of the body, and a glass preform being interposed between the optical fiber and the inlet of the body; and c) applying heat treatment to the glass preform to raise the glass preform to a temperature higher than the melting point of the glass preform so as to form a hermetic sealing element made of glass between the optical fiber and the inlet of the body.

Abstract: A nozzle having a movable diverging section, the nozzle including a stationary throat forming a ball joint and a diverging section having a top portion that is movably mounted around the throat; an annular lubrication chamber being interposed between the stationary throat and the top portion of the diverging section, the annular lubrication chamber containing a grease seal; an annular throttling element arranged between the stationary throat and the diverging section downstream from the annular lubrication chamber, the annular throttling element being made of refractory material; and an annular thermal protection element arranged between the stationary throat and the diverging section downstream from the annular lubrication chamber and upstream from the annular throttling element, the annular thermal protection element closing the lubrication chamber in its bottom portion.

Abstract: A modulator device for modulating a gas ejection section, which device is for placing in a nozzle upstream from the throat of the nozzle and includes a plunger. The plunger has both a proximal portion connected to a control guide and also a distal portion in the form of a body of revolution, the plunger being movable between a retracted position and an extended position. The plunger presents, in its distal portion, a first section of concave shape and a second section of concave shape situated downstream from the first section.

Abstract: A modulation device for modulating a gas ejection section, the device being for placing in a nozzle upstream from the throat of the nozzle, the modulation device including a plug having a downstream end forming a member for partially obstructing the nozzle throat; and a plug guide having an internal housing in which the upstream end of the plug is present. The upstream end of the plug is suitable for sliding in the internal housing of the plug guide between a first position in which the upstream end of the plug is present in an upstream portion of the internal housing, and a second position in which the upstream end is present in a downstream portion of the internal housing. The upstream end of the plug is held in the first position by at least one retaining element for breaking under the effect of heat.

Abstract: A modulator device for modulating a gas ejection section, includes a shutter member for partially shutting a nozzle throat, a control guide of the shutter member, a main piston, and a primer piston. The control guide is movable between a retraction position for retracting the partial shutter element relative to the nozzle throat and a shutting position in which the partial shutter element is in contact with the nozzle throat. The primer piston is movable between a rest position and a priming position for priming the main piston when the pressure in the modulator device reaches a first predetermined value. The main piston is movable between a first position for locking the control guide against movement in its retraction position, and a second position for locking the control guide when the pressure in the modulator device reaches a second predetermined value less than the first predetermined value.

Abstract: A nozzle of variable throat section for an aerospace vehicle thruster, the nozzle including a cylindrical housing presenting a throat of aperture diameter less than the diameter of the housing, and a needle suitable for sliding inside the housing between a high discharge rate front position in which the nose is set back from the throat of the housing, and a low discharge rate rear position in which the nose is in abutment against the throat, the needle including a rod for sliding inside the housing of the nozzle, the rod terminating in a nose of decreasing diameter. The nose of the rod is suitable for coming into abutment against the throat of the nozzle housing forming a seat and includes at least two axial grooves formed in its outer periphery to allow gas to pass when the nose is axially in abutment against the throat of the housing of the nozzle.

Abstract: A combined steering and drag reduction device for a missile is disclosed. The device includes a base and an upper part which are arranged in succession along a main axis of navigation of the missile. Advantageously, the device also includes a pressurized-gas generator and at least one lateral thruster having at least one nozzle configured to deliver a thrust, by expanding gas transmitted by the generator and oriented along an axis substantially perpendicular to the main axis. The at least one lateral thruster also has at least one stabilizing chamber configured to expand the gas transmitted by the generator and expel it through an outlet section of the base substantially perpendicular to the main axis.

Abstract: A modulator device for modulating a gas ejection section, includes a shutter member for partially shutting a nozzle throat, a control guide of the shutter member, a main piston, and a primer piston. The control guide is movable between a retraction position for retracting the partial shutter element relative to the nozzle throat and a shutting position in which the partial shutter element is in contact with the nozzle throat. The primer piston is movable between a rest position and a priming position for priming the main piston when the pressure in the modulator device reaches a first predetermined value. The main piston is movable between a first position for locking the control guide against movement in its retraction position, and a second position for locking the control guide when the pressure in the modulator device reaches a second predetermined value less than the first predetermined value.

Abstract: A nozzle of variable throat section for an aerospace vehicle thruster, the nozzle including a cylindrical housing presenting a throat of aperture diameter less than the diameter of the housing, and a needle suitable for sliding inside the housing between a high discharge rate front position in which the nose is set back from the throat of the housing, and a low discharge rate rear position in which the nose is in abutment against the throat, the needle including a rod for sliding inside the housing of the nozzle, the rod terminating in a nose of decreasing diameter. The nose of the rod is suitable for coming into abutment against the throat of the nozzle housing forming a seat and includes at least two axial grooves formed in its outer periphery to allow gas to pass when the nose is axially in abutment against the throat of the housing of the nozzle.

Abstract: A nozzle having a movable diverging section, the nozzle including a stationary throat forming a ball joint and a diverging section having a top portion that is movably mounted around the throat; an annular lubrication chamber being interposed between the stationary throat and the top portion of the diverging section, the annular lubrication chamber containing a grease seal; an annular throttling element arranged between the stationary throat and the diverging section downstream from the annular lubrication chamber, the annular throttling element being made of refractory material; and an annular thermal protection element arranged between the stationary throat and the diverging section downstream from the annular lubrication chamber and upstream from the annular throttling element, the annular thermal protection element closing the lubrication chamber in its bottom portion.

Abstract: A combined steering and drag reduction device for a missile is disclosed. The device includes a base and an upper part which are arranged in succession along a main axis of navigation of the missile. Advantageously, the device also includes a pressurized-gas generator and at least one lateral thruster having at least one nozzle configured to deliver a thrust, by expanding gas transmitted by the generator and oriented along an axis substantially perpendicular to the main axis. The at least one lateral thruster also has at least one stabilizing chamber configured to expand the gas transmitted by the generator and expel it through an outlet section of the base substantially perpendicular to the main axis.

Abstract: A metal coating is formed on the inside face of a first thermostructural composite material part presenting indentations forming channels, and also on the inside face of a second thermostructural composite material part for being applied against the inside face of the first part, and the first and second parts are assembled together by bonding said inside faces together by hot compression, in particular by hot isostatic pressing, thereby obtaining a thermostructural composite material cooling panel having integrated fluid flow channels. The invention is applicable to making heat exchanger walls such as the walls of combustion chambers in aircraft engines, or the diverging portions of rocket engines, or plasma confinement chambers in nuclear fusion reactors.

Abstract: The active cooling panel comprises a first part and a second part of thermostructural composite material, each having an inside face and an opposite outside face, the parts being assembled together by bonding their inside faces together, and channels being formed by indentations formed in the inside face of at least one of the first and second parts. The panel further includes a sealing layer bonded to at least one of the first and second parts and situated at a distance from the assembled-together inside faces thereof. The invention is applicable to making heat exchanger walls such as the walls for the combustion chambers of aircraft engines, or the diverging portions of rocket engines, or plasma confinement chambers in nuclear fusion reactors.

Abstract: The heat exchanger comprises an intermediate portion (14) of refractory composite material, e.g. of C/C composite material, in which fluid circulation channels (16) are formed, and which is interposed between a portion of refractory composite material, e.g. having a ceramic matrix, such as C/SiC composite material, forming a heat shield (12) and a portion of thermostructural composite material, e.g. C/C composite material, forming a heat exchanger support structure (18), the component portions of the heat exchanger being assembled together by brazing. The heat exchanger can be used as a wall element exposed to an intense heat flux, in particular in a nuclear fusion reactor or in a ram jet combustion chamber.