An artificial satellite comprising: - a plurality of thrusters; - an angular momentum detection apparatus configured to detect an angular momentum that is generated in the artificial satellite; - a satellite controller configured to select, from the plurality of thrusters, a target thruster whose thrust is to be adjusted, based on the detected angular momentum, and to adjust the thrust of the target thruster; - a receiver configured to receive a type instruction from an earth station to instruct one of a current change and a voltage change; - a plurality of power supply apparatuses, associated with the plurality of thrusters, configured to supply a discharge voltage to each of the plurality of thrusters, supply adjustment electric power to adjust a flow rate of a propellant that flows through each of the plurality of thrusters, and detect a discharge current that flows through each of the plurality of thrusters; and - a plurality of flow rate adjustment apparatuses configured to adjust the flow rate of the propellant that flows through each of the plurality of thrusters by the adjustment electric power that is supplied, wherein the satellite controller is configured to output a current change instruction to instruct a change in the discharge current that flows through the target thruster when the type instruction instructs the current change, and to output a voltage change instruction to instruct a change in the discharge voltage that is supplied to the target thruster when the type instruction instructs the voltage change, wherein when the current change instruction is output, the power supply apparatus is configured to change the adjustment electric power, the flow rate adjustment apparatus is configured to flow the propellant through the target thruster at a flow rate corresponding to the adjustment electric power after the change, the power supply apparatus is configured to change the adjustment electric power for the target thruster when the detected discharge current does not become a target current, and wherein when the voltage change instruction is output, the power supply apparatus is configured to change the discharge voltage that is supplied to the target thruster to a target voltage. - a plurality of thrusters; - an angular momentum detection apparatus configured to detect an angular momentum that is generated in the artificial satellite; - a satellite controller configured to select, from the plurality of thrusters, a target thruster whose thrust is to be adjusted, based on the detected angular momentum, and to adjust the thrust of the target thruster; - a receiver configured to receive a type instruction from an earth station to instruct one of a current change and a voltage change; - a plurality of power supply apparatuses, associated with the plurality of thrusters, configured to supply a discharge voltage to each of the plurality of thrusters, supply adjustment electric power to adjust a flow rate of a propellant that flows through each of the plurality of thrusters, and detect a discharge current that flows through each of the plurality of thrusters; and - a plurality of flow rate adjustment apparatuses configured to adjust the flow rate of the propellant that flows through each of the plurality of thrusters by the adjustment electric power that is supplied, wherein the satellite controller is configured to output a current change instruction to instruct a change in the discharge current that flows through the target thruster when the type instruction instructs the current change, and to output a voltage change instruction to instruct a change in the discharge voltage that is supplied to the target thruster when the type instruction instructs the voltage change, wherein when the current change instruction is output, the power supply apparatus is configured to change the adjustment electric power, the flow rate adjustment apparatus is configured to flow the propellant through the target thruster at a flow rate corresponding to the adjustment electric power after the change, the power supply apparatus is configured to change the adjustment electric power for the target thruster when the detected discharge current does not become a target current, and wherein when the voltage change instruction is output, the power supply apparatus is configured to change the discharge voltage that is supplied to the target thruster to a target voltage.