Already before the discovery of pulsed radio sources, the possibility had been discussed1,2 of rotating neutron stars providing an energy source in supernova remnants. A large number of models have been proposed to explain the pulsed radio sources and some of these invoke a central neutron star, some kind of rotation and some kind of in-homogeneity. In the preceding article Gold has proposed a model in which the neutron star, surrounded only by a tenuous plasma, rotates itself with the inhomogeneity residing merely in the star’s magnetic field. Another model3 considers the possibility that the rotation and inhomogeneity both reside in the orbital motion of a satellite around a neutron star. We discuss here some difficulties associated with models for pulsed radio sources which invoke the orbiting of material satellites around any central object.