Abstract: In order to control the attitude of a satellite having at least four gyroscopic actuators with respective spinners mounted on gimbals steerable about axes parallel to one or the other of only two different directions that are fixed relative to the satellite, the attitude of the satellite is measured using sensors on board the satellite, the control torque required to perform an attitude-changing maneuver is calculated, local linearization calculation is performed based on pseudo-inversion of the Jacobean matrix of the function associating the orientations of the actuator gimbals with the total angular momentum of the cluster in order to determine a new gimbal orientation, and precession speeds of at least one of the gimbals of the actuators are controlled to deliver the control torque for reaching the desired configuration.

Abstract: An optical splitting device is intended to receive at an input two beams of different wavelengths. The device includes a polarizing beam splitter designed to selectively transmit part of the beam having one of the wavelengths towards a first output or a second output depending on the polarization of said beam. The device further includes a polarization variation system placed upstream of the polarizing beam splitter. By combining the polarization variation device with the polarizing beam splitter it is possible to adjust the distribution of the energy of a beam between the two outputs of the device. Such a splitting device is advantageously incorporated into an optical communication terminal.

Abstract: The invention concerns a space craft, such as a telecommunication geostationary satellite, comprising a body, at least one main telecommunication antenna having a specific orientation relative to the body, at least a omnidirectional antenna having a field of view opposite to that of the main antennae and at least a radiator extensible by tilting about an axis linked to the craft body between a stowing position wherein it is pressed against the body and an extended position. The axis is positioned substantially in the plane of one surface of the body parallel to the orientation of the omnidirectional antenna and to the surfaces or the surface bearing the main antenna. The radiator tilts at an angle close to 180° from a position wherein it is pressed against one surface bearing a solar panel to a position wherein it extends substantially in the plane of the surface which bears it when it is stowed.