The overall launch mass of a communications satellite has a major influence on its economic performance. If this mass can be reduced substantially, the launch cost will be lower, or more revenue can be generated by carrying a larger payload or extending the operational lifetime. Since an ion propulsion system provides an exhaust velocity at least an order of magnitude higher than that of chemical thrusters, the propellant mass required for north–south station-keeping can be reduced by hundreds of kilogrammes, thereby gaining these benefits. This application of ion propulsion is discussed and quantified in the paper, for the Intelsat VII spacecraft and the UK-10 ion propulsion system.