Numerical Simulations of the Lunar Penetrating Radar and Investigations of the Geological Structures of the Lunar Regolith Layer at the Chang’E 3 Landing Site

Chunyu Ding,Yuan Xiao,Shun Dai,Chunlai Li,Shuguo Xing,Yan Su,Danqing Liu,Jianqing Feng

doi:10.1155/2017/3013249

Abstract

In the process of lunar exploration, and specifically when studying lunar surface structure and thickness, the established lunar regolith model is usually a uniform and ideal structural model, which is not well-suited to describe the real structure of the lunar regolith layer. The present study aims to explain the geological structural information contained in the channel 2 LPR (lunar penetrating radar) data. In this paper, the random medium theory and Apollo drilling core data are used to construct a modeling method based on discrete heterogeneous random media, and the simulation data are processed and collected by the electromagnetic numerical method FDTD (finite-difference time domain). When comparing the LPR data with the simulated data, the heterogeneous random medium model is more consistent with the actual distribution of the media in the lunar regolith layer. It is indicated that the interior structure of the lunar regolith layer at the landing site is not a pure lunar regolith medium but rather a regolith-rock mixture, with rocks of different sizes and shapes. Finally, several reasons are given to explain the formation of the geological structures of the lunar regolith layer at the Chang’E 3 landing site, as well as the possible geological stratification structure.

Highlights

The exploration of the internal structure of moon has been ongoing since the first time a human being landed on the surface of the moon in the 1960s
An accurate depth of the lunar regolith is difficult to determine by Lunar Penetrating Radar (LPR)
Comparing the LPR data and the simulated data, the following conclusions are obtained: (1) The lunar model of a heterogeneous random medium is more consistent with the real structure of the lunar regolith than other theoretical models of the lunar regolith layer used in the preceding literature

Summary

Introduction

The exploration of the internal structure of moon has been ongoing since the first time a human being landed on the surface of the moon in the 1960s. The second channel is centered at a 500 MHz frequency, with a resolution of less than 30 cm in the simulated lunar regolith, and it is used to detect the internal structure of the lunar regolith and its thickness. LPR is a surface penetrating radar with a carrier frequency in the nanosecond pulse time domain whose working principle [8] is as follows: the transmitter antenna emits an electromagnetic wave into the lunar subsurface; when the propagating electromagnetic wave meets a heterogeneous medium, layered interface, or other buried object, phenomena such as reflection, diffraction, and scattering occur; the receiving antenna receives echo signals, such as reflections and scatterings; by analyzing and processing the received echo signals, we will obtain information about the geological structure of the lunar regolith along the road of Yutu rover.

The Heterogeneous Random Medium Model of the Lunar Regolith Layer

The Numerical Simulation of LPR Channel 2

Comparison between the LPR Data and Simulated Data

The Interior Structure of the Lunar Regolith at the Chang’E 3 Landing Site

Conclusion and Discussion