Radar reflections from the moon at 425 Mc/s

Abstract

The characteristics of the lunar surface dedu ced from radar-lunar measurements conducted at the U.S. Air Force Trinidad T est Site during 1960 a re discussed . Evidence is presente~ which te nds to con firm t hat, at 425 megacycles per second, thc fron t portion of the moon IS a co mparatIvely smooth reflector while t he back portion behaves as a rough scatterer. The pulse decay of t he average envelope of lunar echoes is found to follow t he slope of the Lomrncl-Seeli ger scatteri ng la w. From the cumulative probab ili t.v dist ribu tions of thc total cross section of t he moon meas ured on t ,,·o different d ay~, it is indi cated t hat 50 percent of t he total cross section measurcments were less t han 5.0 to 8.5 X IOll square meters 01' 117.0 to 119.3 decibels abovc one square meter. Sta t istical data, such as the probability densi ty fun ctions of t he total lunar echo amp litude a nd t he autocorrelation func tion, a re also prese nted. . Th e power density spectr um co mpu tcd from t he au toco rrelation function is co mpart'cl With t he t heoretICal Doppler spread resul t ing from the moon's libration .