The Use of a Passive Spherical Satellite for Communication and Propagation Experiments

The use of a passive satellite for over-the-horizon communication links has been proposed by Pierce and Kompfner. To confirm the theoretical work which has been done to date, NASA is planning to launch an aluminum coated, 100-foot-diameter plastic sphere for such a communication relay. In addition to confirming the feasibility of a communication link, the NASA sphere can be instrumental in confirming theoretical work in UHF propagation characteristics. With regard to conducting propagation studies, an essential requirement is that the sphere´s scattering properties be described in advance of the experiment. The scattering properties of a metallic sphere (whose radius is very large with respect to the wavelength of the incident radiation) are described in this article. It is shown that the sphere´s scattered field pattern is a function of the incident radiation´s polarization scheme, and that the choice of any particular polarization scheme depends upon the experiment to be performed.