Symposium on Radar and Radiometric Observations of Venus during the 1962 Conjunction: Venus characteristics by earth-based radar

This paper describes three types of radar experiments which were performed upon Venus during the inferior conjunction of November 1962. In the first, only the total echo power was measured, while in the second, this power was analyzed into its frequency components. The third type divided the echo power into range zones and then subdivided these into frequency components. The resulting data indicate the following characteristics: an average radar cross section for Venus of 10%; the cross section fluctuates from day to day; a roughness characteristic, or scattering law, which also fluctu- ates; and the surprising result that Venus rotates retrograde with a period of about 250 days and with its axis nearly perpendicular to its orbit.