A review of radar studies of planetary surfaces

In recent years, radar has been used to study the surfaces of the planets Mercury, Venus, Mars, and Jupiter. In the case of Venus, attenuation in the planetary atmosphere at short wavelengths has also been reported. For Mercury and Venus , where the diurnal rotation is difficult to establis h by other mea ns, radar has provided a clear-cut determination of the sidereal periods as 59 and 247 days, re spec tively.