The electromagnetic propagation characteristics of venus and mars

The information available about Mars and Venus and their atmospheres has been examined to determine the electro-magnetic propagation characteristics of each planet. Consideration of some preliminary model atmospheres [6] indicates that the electro-magnetic propagation effective radius of Venus is between 7400 and 13 900 km. Other models are discussed which give even larger effective radii and lead to the limit of a plane surface. The troposphere of Mars, because of its low density, was shown to have essentially no effect on the propagation loss between points on the surface or near the surface. An examination of the knowledge of the dielectric constants and conductivities of the surface revealed considerable uncertainties, Measured values of the dielectric constant are between 2.2 and 7.1 for the Venusian surface. The conductivity probably is 10^-3mhos/meter or less for both the Venusian and Martian surfaces if they have compositions similar to dry terrestrial soil. No measurement of the dielectric constant of the surface of Mars has been published. Mars and Venus are strongly believed to have ionospheres in their atmospheres, but only crude estimations are available for the electron densities and the altitudes of these ionospheres.