Evidence that the Moon is a rough scatterer at radio frequencies

Abstract

Radar echoes from the moon have been observed at 400 Mc/s for the purpose of determining the scattering properties of the moon. The results go beyond the investigations of other authors who claim that the moon is a quasi-smooth reflector having a range depth of less than 600 μsec. Results described in this report indicate that, although the moon behaves as a quasi-smooth reflector in the 0- to 600-μsec range depth, beyond this range the moon behaves as a uniformly rough scatterer, giving echoes out to 1 lunar radius or the limit of visibility of the moon's surface from the earth. An empirical fit to the integrated range versus time display provides an angular scattering law for each infinitesimal area of the surface given by: P(ϕ) ∝ [(sin θ)/θ]20±6+1/10 A procedure for mapping the details of the moon's surface by radar, using range and Doppler shift coordinates, is suggested. This technique does not require angular resolution.