It is of great interest to compare the results of the chemical analysis of the lunar surface material made by ‘Surveyor’ with that based on the data of the radio astronomical investigations of the electromagnetic properties of the lunar material. The method of determining the chemical composition by the equipment brought onto the moon by Surveyor 7 has been described by Turkevich et al. [1968].

From ground-based optical observations of the moon, attempts to estimate the chemical composition of the lunar surface material have been made, for example, by comparing the polarization properties with those observed for terrestrial rocks. Yet, optical methods are not very effective, as their results depend chiefly on the geometrical properties of the surface (i.e. the roughness). Radar measurements provide the reflection coefficient and some limited data on the nature of the lunar material. They allow, for example, one to distinguish between a metallic and a dielectric reflector.