Abstract: A method for acquiring images by a spacecraft is disclosed having an observation instrument and a laser transmission module, the method including a phase of acquiring an image of the surface of the Earth and a phase of transmitting images using the laser transmission module, and during each acquisition phase and each transmission phase, the attitude control includes: a pointing modification step during which the attitude of the spacecraft is modified so as to orient the satellite towards a predetermined setpoint, a pointing immobilization step during which the attitude of the spacecraft is controlled for a time interval referred to as an immobilization period so as to keep the spacecraft oriented towards the setpoint.

Abstract: A method (50) for image acquisition by a spacecraft (10) comprising an observation instrument (20) and a laser transmission module (30), the method includes: acquiring an image of a calibration area referred to as a calibration image, by the observation instrument (S50), obtaining reference data associated with the calibration area (S51), determining a pointing error of a laser line of sight by comparing the calibration image and the reference data (S52), controlling the pointing of the spacecraft by correcting the pointing error, in order to point the laser line of sight towards a laser reception module (S53), and transmitting data to the laser reception module by the laser transmission module (S54).

Abstract: A method (50) for image acquisition by a spacecraft (10) comprising an observation instrument (20) and a laser transmission module (30), the method includes: acquiring an image of a calibration area referred to as a calibration image, by the observation instrument (S50), obtaining reference data associated with the calibration area (S51), determining a pointing error of a laser line of sight by comparing the calibration image and the reference data (S52), controlling the pointing of the spacecraft by correcting the pointing error, in order to point the laser line of sight towards a laser reception module (S53), and transmitting data to the laser reception module by the laser transmission module (S54).

Abstract: A method (50) of acquiring images of a terrestrial region Z using a spacecraft (10) in non-geostationary orbit around the Earth (30), the spacecraft includes an observation instrument associated with a ground footprint of length L along the direction of travel, the method includes: a step (51) of observing a portion P1 of the terrestrial region Z, including a step of controlling the attitude of the spacecraft (10) during which the ground footprint is kept stationary during the entirety of the step of observing portion P1, and a step of acquiring an image of portion P1, a step (52) of modifying the pitch attitude of the spacecraft (10) so as to place the ground footprint over a portion P2 of the terrestrial region Z, and a step (53) of observing portion P2 of the terrestrial region.

Abstract: A method (50) of acquiring images of a terrestrial region Z using a spacecraft (10) in non-geostationary orbit around the Earth (30), the spacecraft includes an observation instrument associated with a ground footprint of length L along the direction of travel, the method includes: a step (51) of observing a portion P1 of the terrestrial region Z, including a step of controlling the attitude of the spacecraft (10) during which the ground footprint is kept stationary during the entirety of the step of observing portion P1, and a step of acquiring an image of portion P1, a step (52) of modifying the pitch attitude of the spacecraft (10) so as to place the ground footprint over a portion P2 of the terrestrial region Z, and a step (53) of observing portion P2 of the terrestrial region.

Abstract: A method of controlling the attitude of a satellite (1) including two gyrodynes (3,4) and a third main actuator (2) which delivers torques at least along the Z axis. The method includes: fixing the gimbal axes, A1 and A2, of the gyrodynes (3, 4) parallel to Z; setting a non-zero bias (?) between the angular momentum vectors (Formula I) of the gyrodynes; using the measurements provided by the sensors on board the satellite to estimate the kinematic and dynamic variables necessary in order to control the attitude of the satellite (1); calculating set variables in order to the objectives assigned to the satellite (1) attitude control system; and using the deviations between the estimated variables and the set variables to calculate control orders and to send same to the main actuators (2, 3, 4).

Abstract: The invention relates to a method of controlling the attitude of a satellite (1) comprising two gyrodynes (3,4) and a third main actuator (2) which delivers torques at least along the Z axis.