The emerging generation of personal communications satellites, built to communicate with handheld telephone units, will generate power flux on earth that is orders of magnitude higher than that of the present satellite service, and its potential interference with terrestrial-based systems is of concern. It is proposed here that the flux scattered from the ground surface into the antenna main beam and near sidelobes may cause higher interference than direct coupling into the antenna. This mechanism, previously observed in terrestrial systems, may not be mitigated by adaptive hulling techniques, and is less angle-dependent. A simple model is developed, to be used as a computational tool for assessing the interference and its functional dependence on governing parameters. In the absence of proper terrain scattering models, examples are evaluated by borrowing results from interference observed in terrestrial microwave links, which indicate the possible severity of the effect.