Methods for attitude control of a satellite in survival mode without a priori knowledge of the local time of the satellite's orbit

A method for attitude control of a satellite in inclined low orbit in survival mode, the satellite comprising at least one solar generator, at least one solar sensor, magnetic torquers capable of forming internal magnetic moments in a satellite reference frame comprising three orthogonal axes X, Y, and Z, and inertial actuators capable of forming internal angular momentums in said satellite reference frame, wherein the at least one solar sensor has a field of view at least 180° wide in a XZ plane around the Z axis, the at least one solar generator is stationary in the satellite reference frame during survival mode and directed so as to generate electrical energy when the sun (S) is located along the Z axis within a field of view of the at least one solar sensor, wherein the method comprises:

• a step of attitude control using a first control law according to which the magnetic torquers are controlled to form torques along the X, Y, and Z axes in order to limit the variations of the Earth's magnetic field in the satellite reference frame, and the inertial actuators are controlled to form an internal angular momentum along the X axis,
• a step of searching for the sun by means of the at least one solar sensor configured to detect whether the satellite is in a phase of visibility of the sun,
• responsive to a detection of a first phase of visibility of the sun:
• a step of attitude control using a second control law according to which the magnetic torquers are controlled to limit variations of the Earth's magnetic field in the satellite reference frame by forming attitude control torques along the Z axis, and the inertial actuators are controlled to form torques along the X and Y axes to place and maintain the satellite in an attitude in an inertial reference frame in which the at least one solar generator is directed towards the sun.