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.