Abstract: A deformable mirror comprises a deformable membrane extending at rest in a first plane and having a reflecting front face and a back face opposite the front face, a supporting structure, an actuator having a first and second end, the first end fixed to the supporting structure, the second end displaced relative to the first end on a first axis substantially at right angles to the first plane to exert, on the back face, an axial load on the first axis, to locally deform the deformable membrane. The mirror comprises a plate that is substantially flat in a second plane substantially parallel to the first plane, positioned between the actuator and deformable membrane, linked to the back face and deformed when the actuator exerts the axial load, and the plate is rigid in the second plane to take up loads applied to the mirror in the second plane.

Abstract: A method for producing a mirror comprising a plurality of optical surfaces, the method comprises: a step of producing elements, step of assembling the elements with each other from the rear, a step of fixing the elements from the rear onto a supporting structure of the mirror, and a step of polishing subsequent to the step of fixing the elements in order to obtain the optical surfaces of the mirror and correct the residual positioning defects of the optical surfaces and polish them.

Abstract: A nanometer-scale precision actuator comprises a base, an intermediate structure, an output interface, and two linear elements producing a controllable extension in the same longitudinal direction, each between a first and a second end. A first of the two elements has a first end fixed onto the intermediate structure and a second end fixed onto the base, a second of the two elements has a first end fixed onto the intermediate structure and a second end fixed to the output interface. The base and the intermediate structure are positioned in such a manner that the controllable extension of the second element produces a displacement of the actuator in a first direction and the controllable extension of the first element produces a displacement of the actuator in a second direction, opposite to the first direction, with respect to the base.

Abstract: A deformable mirror comprises a deformable membrane extending at rest in a first plane and having a reflecting front face and a back face opposite the front face, a supporting structure, an actuator having a first and second end, the first end fixed to the supporting structure, the second end displaced relative to the first end on a first axis substantially at right angles to the first plane to exert, on the back face, an axial load on the first axis, to locally deform the deformable membrane. The mirror comprises a plate that is substantially flat in a second plane substantially parallel to the first plane, positioned between the actuator and deformable membrane, linked to the back face and deformed when the actuator exerts the axial load, and the plate is rigid in the second plane to take up loads applied to the mirror in the second plane.

Abstract: A method for correcting the thermoelastic effects on performance parameters of a telescope on board a space satellite, comprises a first step prior to the flight of the satellite consisting in determining, a priori, a correction of the thermoelastic effects by using a prior model of variations of the thermoelastic effects on the orbital scale and an algorithm for determining correction fed by programming data of the space satellite, and a second step carried out in flight, based on the correction determined a priori, consisting in establishing control messages of correction means for correcting the performance parameters of said telescope.

Abstract: A honeycomb structure comprises a front part and a rear part. The front and rear parts are honeycomb structures composed of a skin and of stiffeners as a single component, the stiffeners being formed of intermeshing blades oriented substantially perpendicularly to said skin. The two parts comprise protuberances on the stiffeners on the face opposite to the skin and these protuberances are disposed on the front and rear parts in such a manner that each protuberance of the front part is located opposite a protuberance of the rear part when the two parts are superposed. The two parts are assembled by attachment devices into which two opposing protuberances are inserted.

Abstract: An optical monitoring device for an optical imaging system having a focal plane, an optical axis and an entry pupil, forming an image of a scene substantially at infinity on an image detector disposed substantially in the focal plane, comprises: a virtually point-like emission source at the periphery of the detector and substantially in the focal plane; a reflecting element with a plane surface upstream of the imaging system relative to the direction of light rays coming from the scene, and according to a position and inclination where a monitoring image of the source produced by the optical system and reflected by the reflecting element is substantially in the focal plane on a detection element connected to a monitoring image analyzer allowing potential optical defects to be identified; the reflecting element having an annular shape allowing passage of light rays coming from the scene and passing through the entry pupil.

Abstract: A method for producing a mirror comprising a plurality of optical surfaces, the method comprises: a step of producing elements, step of assembling the elements with each other from the rear, a step of fixing the elements from the rear onto a supporting structure of the mirror, and a step of polishing subsequent to the step of fixing the elements in order to obtain the optical surfaces of the mirror and correct the residual positioning defects of the optical surfaces and polish them.

Abstract: A nanometer-scale precision actuator comprises a base, an intermediate structure, an output interface, and two linear elements producing a controllable extension in the same longitudinal direction, each between a first and a second end. A first of the two elements has a first end fixed onto the intermediate structure and a second end fixed onto the base, a second of the two elements has a first end fixed onto the intermediate structure and a second end fixed to the output interface. The base and the intermediate structure are positioned in such a manner that the controllable extension of the second element produces a displacement of the actuator in a first direction and the controllable extension of the first element produces a displacement of the actuator in a second direction, opposite to the first direction, with respect to the base.

Abstract: A honeycomb structure comprises a front part and a rear part. The front and rear parts are honeycomb structures composed of a skin and of stiffeners as a single component, the stiffeners being formed of intermeshing blades oriented substantially perpendicularly to said skin. The two parts comprise protuberances on the stiffeners on the face opposite to the skin and these protuberances are disposed on the front and rear parts in such a manner that each protuberance of the front part is located opposite a protuberance of the rear part when the two parts are superposed. The two parts are assembled by attachment devices into which two opposing protuberances are inserted.

Abstract: A device for correcting optical defects of a telescope mirror, compatible with use in a space environment, is provided, where the criteria of weight, reliability, service life, cost and resistance to extreme temperatures are fundamental. The device comprises at least one controllable-length element, means for controlling the length of this element, this element being connected to the mirror by its ends in zones that are diametrically or diagonally opposed and close to the periphery of this mirror, the connection between the controllable-length element and the mirror comprising attachments that are rigid on the axis joining these two attachment zones and flexible in the other degrees of freedom.

Abstract: An optical monitoring device for an optical imaging system having a focal plane, an optical axis and an entry pupil, forming an image of a scene substantially at infinity on an image detector disposed substantially in the focal plane, comprises: a virtually point-like emission source at the periphery of the detector and substantially in the focal plane; a reflecting element with a plane surface upstream of the imaging system relative to the direction of light rays coming from the scene, and according to a position and inclination where a monitoring image of the source produced by the optical system and reflected by the reflecting element is substantially in the focal plane on a detection element connected to a monitoring image analyzer allowing potential optical defects to be identified; the reflecting element having an annular shape allowing passage of light rays coming from the scene and passing through the entry pupil.

Abstract: A method for correcting the thermoelastic effects on performance parameters of a telescope on board a space satellite, comprises a first step prior to the flight of the satellite consisting in determining, a priori, a correction of the thermoelastic effects by using a prior model of variations of the thermoelastic effects on the orbital scale and an algorithm for determining correction fed by programming data of the space satellite, and a second step carried out in flight, based on the correction determined a priori, consisting in establishing control messages of correction means for correcting the performance parameters of said telescope.

Abstract: The invention relates to an optical instrument (1) comprising at least one mirror called the primary mirror (3), placed in a cavity (2) and comprising an active face capable of being subjected to instantaneous variations of the incident radiative flux. According to the invention, the cavity (2) comprises a rigid internal casing (20) around the mirror consisting of a material having a thermal inertia so as to damp the instantaneous variations of the incident radiative flux thereby making it possible to limit the temperature fluctuations of this cavity and, consequently, the temperature fluctuations of the mirror. The invention applies to the space field.

Abstract: A device for correcting optical defects of a telescope mirror, compatible with use in a space environment, is provided, where the criteria of weight, reliability, service life, cost and resistance to extreme temperatures are fundamental. The device comprises at least one controllable-length element, means for controlling the length of this element, this element being connected to the mirror by its ends in zones that are diametrically or diagonally opposed and close to the periphery of this mirror, the connection between the controllable-length element and the mirror comprising attachments that are rigid on the axis joining these two attachment zones and flexible in the other degrees of freedom.

Abstract: The invention relates to an optical instrument (1) comprising at least one mirror called the primary mirror (3), placed in a cavity (2) and comprising an active face capable of being subjected to instantaneous variations of the incident radiative flux. According to the invention, the cavity (2) comprises a rigid internal casing (20) around the mirror consisting of a material having a thermal inertia so as to damp the instantaneous variations of the incident radiative flux thereby making it possible to limit the temperature fluctuations of this cavity and, consequently, the temperature fluctuations of the mirror. The invention applies to the space field.