The link communication from/to satellite, re-entry or space vehicles is often subject to degradation known as black-out. To assess this issue, radio frequency (RF) wave propagation through complex media (such ionosphere, plasmas and complex gas mixtures) must be considered. Asymptotic techniques such as ray or beam tracing can be used to predict EM propagation in these inhomogeneous media where the radiation can be refracted, reflected and/or absorbed compared to free-space propagation. Coupled with integral equations for the free-space part of the simulation domain, the model provides a powerful numerical tool to design antennas for critical applications and for calculating the Radar Cross Section (RCS) of objects surrounded by complex media such as hypersonic plasma.