Abstract: A device for controlling the attitude of a satellite exploiting solar pressure, includes at least two solar generators destined to be arranged on either side of a central body of the satellite and each having one face to be exposed to the Sun, referred to as “front face”, the device also including at least three surfaces whose optical properties can be commanded. The surfaces whose optical properties can be commanded are arranged on flaps connected to solar generators, each flap being fixed with respect to the solar generator to which it is connected, and such that, in the operating position, at least two of the surfaces are not parallel when the front faces of the solar generators are optimally oriented with respect to the Sun. The device further includes a module for commanding the optical properties of each surface whose optical properties can be commanded.

Abstract: A method for calibrating a threshold for selecting a transmission format, from a plurality of transmission formats, in order to exchange data packets over a radio-frequency propagation channel, referred to as the “channel” (L1, L2, L3) between a transmitting device and a receiving device of a satellite telecommunications system, includes: calculating a calibration table for the threshold, which associates transmission statistics, representative of an amount of estimated errors for a plurality of data packets received by the receiving device, with a plurality of values of the instantaneous channel quality; and updating the threshold, which, according to the calibration table, is a value of the instantaneous channel quality enabling a predefined value of the transmission statistics to be provided. A threshold calibration module, which can be included in a terrestrial terminal (2), and/or a satellite (3), and/or, more generally, in a satellite telecommunications system, is also described.

Abstract: The subject of the invention is a device for starting a turbopump of a rocket motor of an aircraft including a turbine engine for propelling the aircraft and a rocket motor, which includes a pneumatic supply of compressed air to a turbine of the turbopump, this compressed air being tapped from a tapping on a compressor stage of the aircraft propulsion turbine engine upstream of the combustion chamber of the turbine engine. It applies notably to an aircraft of the space airplane type.

Abstract: A method and system for estimating a direction of arrival of a target signal relative to a measuring antenna array of an earth-orbiting satellite. The direction of arrival of the target signal being estimated on the basis of measurement signals corresponding to the target signal received respectively by at least a first measuring antenna and a second measuring antenna of the measuring antenna array. Each of the measurement signals are combined with a reference signal corresponding to the target signal received by a receiving antenna of the satellite. The receiving antenna has a maximum gain greater than the respective maximum gains of the first measuring antenna and of the second measuring antenna. The direction of arrival of the target signal is estimated from the signals obtained by combining the measurement signals with the reference signal.

Abstract: An optical system has a rotary scanning mirror, an optical instrument and an optical image rotation device. The rotary scanning mirror receives an incident beam of rays and returns an input beam along a first axis. The optical instrument receives the input beam from the scanning mirror and returns an output beam parallel to the input beam along a second axis in a direction opposite to the input beam towards the optical rotation device. The optical image rotation device is positioned on the second axis and receives the output beam. The scanning mirror has an axis of rotation aligned on the first axis. The optical image rotation device has an axis of rotation aligned on the second axis. The optical system comprises a common driving device for rotationally driving the optical image rotation device and the scanning mirror about their respective rotation axes.

Abstract: According to the invention, said space aircraft comprises, at the front of each of the air inlets of the turbo engines, a mobile flap that can move, in both directions, between a first position for which said flap opens said air inlet and a second position for which said flap prevents air from entering said air inlet.

Abstract: Method for estimating shifts of line images obtained by an airborne or spaceborne scanning sensor. The invention relates to a method for estimating shifts in line images of an image, referred to as a “composite image”, made up of the juxtaposition of J line images. The line images show portions of a scene on the surface (S) of a celestial body that are different and successively acquired by a row of sensitive cells of a sensor (10) on board a vehicle flying over the celestial body. The shifts in the line images are induced by sighting errors of the sensor (10) during the acquisition of the line image Lj. The lateral and/or longitudinal shift of a line image Lj relative to a line image Li, where j is different from i, is estimated according to a local model of lateral and/or longitudinal variation of the similarity between different line images.

Abstract: A multi-beam telecommunications satellite, intended to be placed in orbit around the earth, and adapted to relay data between terrestrial terminals and at least one ground station and to form beams on a user link between the satellite and terrestrial terminals, includes a module for forming beams on board in the satellite, a module for processing beams in the ground station, and a module for routing signals received from the ground station and/or from terrestrial terminals, signals of beams formed on board being routed towards the on-board beam forming module, and signals of ground-formed beams being routed towards the ground-formed beam processing module. A telecommunications system including the multi-beam satellite, a ground station and a beam management center adapted to divide the beams into one group of ground-formed beams and one group of beams formed on board, as well as a method for forming beams are disclosed.

Abstract: Method for estimating the movement of an observation instrument on-board a vehicle flying over a celestial body, the instrument including at least two strips with different lines of sight, each strip realizing the acquisition of successive image lines making up a composite image, parts of the composite images representing substantially a same scene of the celestial body. The estimated movement is determined by optimization of an image similarity function that associates, to a given movement hypothesis, a similarity between values of matched pixels of at least a pair of composite images. The method includes, for each movement hypothesis considered during the optimization: determining, for the at least one pair of composite images, at least one spatio-temporal transformation using the considered movement hypothesis and a geometric model of the observation instrument, and matching the pixels of the at least one pair of composite images using the at least one spatio-temporal transformation.

Abstract: A method of command of magneto-torquers of an attitude control system of a space vehicle subjected to an external magnetic field of variable direction. The magneto-torquers are configured to desaturate an angular momentum storage device by transferring angular momentum and configured to form, in cooperation with the local external magnetic field, magnetic couples in a plane orthogonal to the direction of the local external magnetic field or a local control plane. The magnetic couple to be formed in the local control plane is determined as a function of the component of a desired attitude control couple which is orthogonal to the local control plane or a locally uncontrollable component. The contribution of the locally uncontrollable component to the magnetic couple to be formed is non-zero when the locally uncontrollable component is non-zero.

Abstract: The remote communications system, intended for low-throughput data transfer between at least two users located substantially on the surface of a celestial body, includes: a plurality of transmitting/receiving surface terminals, each associated to a user, one or more geostationary element installed on board satellites placed in geostationary orbit around the celestial body, these geostationary elements being able to transmit data from and to a predefined coverage area on the surface of the celestial body with a line of sight to the geostationary satellite, and one or more signal repetition element for the signals transmitted and/or received from the geostationary elements to the surface terminals these traveling repetition elements being on board satellites moving in a traveling orbit; the same frequency band is used for communications between the surface terminals and the traveling elements and for communications between the traveling elements and the geostationary elements.

Abstract: A method and system for estimating a path difference between two paths followed by a target signal transmitted by a spacecraft or aircraft to a first receiving antenna and a second receiving antenna of a receiving base, respectively. A useful-phase difference is measured between signals corresponding to the target signal received on the first receiving antenna and second receiving antenna. The path difference is estimated on the basis of the measurements of the useful-phase difference. A calibration signal is transmitted to the receiving base and a calibration phase difference between signals corresponding to the calibration signal received on the first receiving antenna and second receiving antenna is measured. Variations are compensated in the measurements of the calibration-phase difference relative to the measurements of the useful-phase difference.

Abstract: A rolling bearing device, of the type including a central shaft and a hub (10) mobile in rotation relative to each other, the bearing including at least two rolling bearings (12, 13), one designated “lower” and the other designated “upper”, arranged between the central shaft (11) and the hub (10) in two positions spaced in the axial direction Z, these rolling bearings being fitted with inner (14, 16) and outer (15, 17) rings and with balls (18, 19), the rolling bearings being assembled back-to-back or face-to-face, a rigid preload being applied to these bearings along the axial direction Z, internal (22) and external (23) spacers being arranged between these rolling bearings, the inner (22) and outer (23) spacers have lengths adjusted to limit variations in rigid preload caused by temperature gradients from one point of the bearing to another to less than 30%, particularly thermal gradients in the radial direction.

Abstract: A device for thermal monitoring a piece of equipment, which is integrated on a craft placed in a forced vacuum environment, an outside part of the equipment projecting outside of a wall of the craft and being subjected to a solar radiation flux, includes an absorbent screen that is suitable for being placed between the outside part of the equipment and the wall of the craft, whereby this absorbent screen has—on at least one portion of its front face, designed to be placed on the side removed from the wall of the craft—an absorptivity ?SOLAR that is the largest possible in the field of solar radiation, coupled to a low emissivity ?IR in the infrared spectrum. The absorbent screen is made of a very heat-conductive material and has—on at least a portion of its rear face, suitable for being oriented toward the wall of the craft—a high emissivity ?IR in the infrared spectrum, typically greater than or equal to 0.7.

Abstract: A wing or blade in at least two sections facing each other. Each section has a longitudinal bearing structure provided with at least one sole of which the link between the sections includes at least one first link plate linking the end of the soles of the sections facing each other. A method of producing such wing or blade.

Abstract: A method for calibrating spatial errors induced by phase biases having a detrimental effect on the measurements of phase differences of radio signals received by three unaligned receiving antennas of a vehicle. An inter-satellite angular deviation of a pair of satellites is estimated in two different ways: on the basis of the respective positions of the vehicle and of the satellites to obtain a theoretical inter-satellite angular deviation; and on the basis of the respective directions of incidence of the satellites relative to the vehicle, which are determined from phase measurements, to obtain an estimated inter-satellite angular deviation. The space errors are estimated on the basis of said theoretical and estimated inter-satellite angular deviations. Also, a method and system for estimating the attitude of a vehicle, in particular a spacecraft.