G.F. Adams W.E. Brown Jr. R. E. Eggleton P. Jackson R. Jordan W.I. Linlor W.J. Peeples L.J. Porcello J. Ryu G. Schaber W.R. Sill T.W. Thompson S.H. Ward J.S. Zelenka R.J. Phillips 1973 The scientific objectives of the Apollo lunar sounder experiment (ALSE) are (1) mapping of subsurface electrical conductivity structure to infer geological structure, (2) surface profiling to determine lunar topographic variations, (3) surface imaging, and (4) measuring galactic electromagnetic radiation in the lunar environment. The ALSE was a three-frequency, wide-band, coherent radar system operated from lunar orbit during the Apollo 17 mission. application/pdf en National Aeronautics and Space Administration Apollo lunar sounder experiment chapter