A payload for a satellite comprising: a plurality of beamforming networks; a communication means arranged to receive data in a data sequence from a ground station of a communications network and to transmit the received data via a respective plurality of satellite beams created by the plurality of beamforming networks; storage means arranged to store a beam hopping sequence; a controller arranged to control transmission of data by the communication means according to the stored beam hopping sequence in a manner synchronised with the data sequence from the ground station; and a synchronisation pulse generator arranged to generate a synchronisation pulse at counter reset times separated by a predetermined period of time, measured by a counter, derived from a master clock signal common to the satellite payload and the ground station; wherein the controller is arranged to: (i) receive an update to the beam hopping sequence from the ground station; (ii) determine one or more of the plurality of satellite beams for which the beam hopping sequence is to be updated and configure a respective one or more beamforming networks associated with the determined one or more satellite beams to be responsive to receipt of a synchronisation pulse; (iii) issue a control command to the synchronisation pulse generator to release a generated synchronisation pulse to each of the plurality of beamforming networks at a counter reset time, and to cause the one or more beamforming networks configured to be responsive to receipt of a synchronisation pulse to implement the updated beam hopping scheme at a time synchronised with the counter reset time to enable the counter reset time to be observable at the ground station; and (iv) update the stored beam hopping sequence. a plurality of beamforming networks; a communication means arranged to receive data in a data sequence from a ground station of a communications network and to transmit the received data via a respective plurality of satellite beams created by the plurality of beamforming networks; storage means arranged to store a beam hopping sequence; a controller arranged to control transmission of data by the communication means according to the stored beam hopping sequence in a manner synchronised with the data sequence from the ground station; and a synchronisation pulse generator arranged to generate a synchronisation pulse at counter reset times separated by a predetermined period of time, measured by a counter, derived from a master clock signal common to the satellite payload and the ground station; wherein the controller is arranged to: (i) receive an update to the beam hopping sequence from the ground station; (ii) determine one or more of the plurality of satellite beams for which the beam hopping sequence is to be updated and configure a respective one or more beamforming networks associated with the determined one or more satellite beams to be responsive to receipt of a synchronisation pulse; (iii) issue a control command to the synchronisation pulse generator to release a generated synchronisation pulse to each of the plurality of beamforming networks at a counter reset time, and to cause the one or more beamforming networks configured to be responsive to receipt of a synchronisation pulse to implement the updated beam hopping scheme at a time synchronised with the counter reset time to enable the counter reset time to be observable at the ground station; and (iv) update the stored beam hopping sequence. (i) receive an update to the beam hopping sequence from the ground station; (ii) determine one or more of the plurality of satellite beams for which the beam hopping sequence is to be updated and configure a respective one or more beamforming networks associated with the determined one or more satellite beams to be responsive to receipt of a synchronisation pulse; (iii) issue a control command to the synchronisation pulse generator to release a generated synchronisation pulse to each of the plurality of beamforming networks at a counter reset time, and to cause the one or more beamforming networks configured to be responsive to receipt of a synchronisation pulse to implement the updated beam hopping scheme at a time synchronised with the counter reset time to enable the counter reset time to be observable at the ground station; and (iv) update the stored beam hopping sequence.