Abstract: A satellite designed to be spin-stabilized in geostationary orbit which has, coaxial with a spin rotation axis, a satellite body surrounded with a cylindrical solar generator, an apogee maneuver system disposed along the axis and two axially disposed equipments. The apogee maneuver system has opposite one of the equipments at least two thrusters oriented parallel to the axis but offset relative thereto by the same distance. Equi-angularly spaced around the other of the two equipments, the thrusters are connected to a common liquid propellant feed system.

Abstract: A satellite designed to be spin-stabilized in geostationary orbit which has, coaxial with a spin rotation axis, a satellite body surrounded with a cylindrical solar generator, an apogee maneuver system disposed along the axis and two axially disposed equipments. The apogee maneuver system has opposite one of the equipments at least two thrusters oriented parallel to the axis but offset relative thereto by the same distance. Equi-angularly spaced around the other of the two equipments, the thrusters are connected to a common liquid propellant feed system.

Abstract: An attitude control device for a three-axis stabilized satellite in terrestrial orbit embodies an attitude sensing system adapted to deliver roll, yaw and pitch attitude signals, a set of at least three non-parallel axis momentum wheels and a set of at least two magnetic coils oriented at least approximately in two non-parallel directions in the roll/yaw plane. A primary control loop embodies a processor and controller connected between the attitude sensing system and the set of at least three momentum wheels. It is adapted to determine from attitude signals and attitude set point signals attitude correction signals for the momentum wheels so as to apply to the satellite primary attitude correction torques. A secondary control loop embodies a coil controller connected between the processor and controller, the set of at least three momentum wheels and the set of at least two magnetic coils.

Abstract: A satellite adapted to be spin-stabilized in geostationary orbit having, coaxial with a spin rotation axis, a satellite surrounded with a solar generator. At least two equipments including an apogee maneuver system are disposed along the rotation axis. A set of generally annular antennas including at least one picture transmission antenna is disposed on one of the NORTH and SOUTH faces of the satellite so as to leave at its center a cylindrical space along the spin rotation axis to house one of the equipments. The other of the equipments is disposed on the other of the NORTH and SOUTH faces.

Abstract: The attitude of a satellite carrying terrestrial and solar sensors and spin-stabilized about an axis V--V is determined and controlled prior to its transfer from an elliptical transfer orbit to a circular geostationary orbit by means of an apogee motor firing. The attitude is defined relative to an inertial X-Y-Z frame of reference the Z axis of which is directed towards geographical North, by a declination .alpha. between the axis V--V and the X-Y plane and by a right ascension .beta. between the projection of the axis V--V onto the X-Y plane and the X axis. After injection of the satellite by a launch vehicle into the transfer orbit at its perigee, with an initial attitude approximating the predetermined final attitude for the apogee motor firing, the right ascension .beta. of the satellite is modified to confer on it an intermediate attitude such that the earth is in the field of view of the terrestrial sensors for a position of the satellite in the transfer orbit offset at least 10.degree.

Abstract: A method and apparatus to perform the observation and imaging from a space vehicle by scanning of a celestial body with reference to a scanning axis, forming successively two signals corresponding to the scanning in a given directional series of a line or band including ground area, detecting in each of these signals a characteristic transition representative of a given characteristic point of this line or band of ground, reading the relative position of these transitions in these signals, and determining an angular velocity of the space vehicle from any divergence between these relative positions while taking into account the time interval separating the instants where each of these transitions appeared in the aforementioned formed signals.