Abstract: An orbit transfer method for a spacecraft using a continuous or quasi-continuous thrust propulsion, the method comprises: the acquisition, at least once in each half-revolution of the spacecraft, of measurements of its position and of its velocity; the computation of a thrust control function as a function of the measurements; and the driving of the thrust in accordance with the control law; wherein the control law is obtained from a Control-Lyapunov function using orbital parameters, preferably equinoctial, of the spacecraft, averaged over at least one half-revolution. An embedded driving system for a spacecraft for implementing such a method and a spacecraft equipped with the driving system are provided.

Abstract: A thrust nozzle system is provided for a satellite designed to be stabilized in autorotation over a geostationary orbit, the satellite comprising three reference axes X, Y and Z, the Y axis representing the North/South axis and the Z axis corresponding to an Earth pointing direction. The thrust nozzle system comprises a first set of thrust nozzles configured for maintaining the satellite in station, the first set comprising an even number of thrust nozzles using electrical propulsion, with a pre-adjusted orientation, the even number being equal to at least 4, the thrust nozzles being oriented along three spatial components, and having, taken in pairs, different signs of X and Y components.

Abstract: A method of guidance for placing a satellite on station comprises the following steps carried out during a predefined current cycle: A) determining on the ground a law of orientation of the thrust vector, and a history of state variables and of adjoint state variables of the satellite for the transfer from a starting orbit to a target orbit using optimal control theory, B) determining on the ground a law of evolution of the rotation of the satellite about the thrust vector, on the basis of the orientation law and of the history, C) representing according to a predetermined format the evolution of the state variables and adjoint state variables so as to obtain first parameters, D) representing according to a predetermined format a law of evolution of the rotation so as to obtain second parameters, E) concatenating the first and second parameters so as to obtain a guidance plan for the satellite, F) downloading onboard the guidance plan, G) periodically repeating according to a predefined period which is smalle

Abstract: An orbit transfer method for a spacecraft using a continuous or quasi-continuous thrust propulsion, the method comprises: the acquisition, at least once in each half-revolution of the spacecraft, of measurements of its position and of its velocity; the computation of a thrust control function as a function of the measurements; and the driving of the thrust in accordance with the control law; wherein the control law is obtained from a Control-Lyapunov function using orbital parameters, preferably equinoctial, of the spacecraft, averaged over at least one half-revolution. An embedded driving system for a spacecraft for implementing such a method and a spacecraft equipped with the driving system are provided.

Abstract: A method of guidance for placing a satellite on station comprises the following steps carried out during a predefined current cycle: A) determining on the ground a law of orientation of the thrust vector, and a history of state variables and of adjoint state variables of the satellite for the transfer from a starting orbit to a target orbit using optimal control theory, B) determining on the ground a law of evolution of the rotation of the satellite about the thrust vector, on the basis of the orientation law and of the history, C) representing according to a predetermined format the evolution of the state variables and adjoint state variables so as to obtain first parameters, D) representing according to a predetermined format a law of evolution of the rotation so as to obtain second parameters, E) concatenating the first and second parameters so as to obtain a guidance plan for the satellite, F) downloading onboard the guidance plan, G) periodically repeating according to a predefined period which is smalle

Abstract: A thrust nozzle system is provided for a satellite designed to be stabilized in autorotation over a geostationary orbit, the satellite comprising three reference axes X, Y and Z, the Y axis representing the North/South axis and the Z axis corresponding to an Earth pointing direction. The thrust nozzle system comprises a first set of thrust nozzles configured for maintaining the satellite in station, the first set comprising an even number of thrust nozzles using electrical propulsion, with a pre-adjusted orientation, the even number being equal to at least 4, the thrust nozzles being oriented along three spatial components, and having, taken in pairs, different signs of X and Y components.

Abstract: A method is provided for controlling a set of at least two satellites, designed to provide a service on a geostationary orbit, rendering said service on a non-geostationary orbit, in which means involved in the performance of said service, installed on board a satellite, are deactivated when the sun can damage it, and means involved in the performance of said service installed on board another satellite of the set are activated, when this is necessary to the continuity of the service.

Abstract: A method is provided for controlling a set of at least two satellites adapted to provide a service used by at least one portion of the set of the said satellites at a given moment, in which, continuously or pseudo-continuously, a mean value of the longitudes of the respective ascending nodes of each satellite is computed, and, for each satellite, a correction of trajectory of the satellite is applied by regulating the longitude of the ascending node on a setpoint equal to said current mean value.