A Review of Applications of Radar-Detection Techniques in Lunar Explorations

Fruitful scientific results have been obtained in lunar explorations by using radar techniques. Usages of radars in lunar explorations include probing the lunar topography, inversely deriving data of lunar regolith thickness, probing lunar subsurface structures, and searching for lunar ice/water. In this paper we review some scientific results in domestic and foreign lunar explorations using radars. Our review covers studies of different detection methods and scientific purposes. Recently China successfully launched the 'Chang-E 3' lunar probe with the Lunar Penetrating Radar (LPR) as one of its important payloads. The scientific purposes of the LPR are to explore lunar subsurface structures and to measure thickness values and structures of lunar regolith. Our review particularly introduces the working principle and key-parameter values of the LPR.