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Sampling return in Chang'E-5 (CE-5) mission is the third phase of three strategic steps of China's lunar program. The three strategic steps are orbiting, landing, and returning. The sampling and drilling device is mounted on the Lander. One task of the CE-5 Lunar Regolith Penetrating Radar (LRPR) is to provide information support for the drilling and sampling device. This article introduces the scientific objectives of CE-5 LRPR and the difference with Chang'E-3 lunar penetrating radar. The system design, working principle, imaging, and calibration methods of LRPR are the highlight. Considering that the Lander is stationary, and its bottom is about 90 cm from the lunar surface, an antenna array is adopted to probe the subsurface structure and the regolith thickness for supporting the drilling. The design uses a pre-amplifier circuit to increase the dynamic range of the whole system, which enhances the detection effect of shallow lunar soil structure. For verifying the probing ability of LRPR, the marble slabs, metal balls, and stones are buried in the volcanic ash pool in advance for detection and verification. The pre-stack Kirchhoff depth migration imaging method is adopted to identify the burial depth and thickness of the target. The verification results meet the task requirements.

Lunar Regolith Penetrating Array Radar (LRPR) is one main payload of the Lander for Chinese Chang’E-5 (CE-5) mission. It is used to support the drilling and sampling device and to detect lunar regolith thickness and structure of the landing site. LRPR will only work in situ under static status, so the antenna array is employed. Since the antenna array is about 90 cm high from the ground, the layout is irregular, and the metal structure of the lander seriously interferes with LRPR, these factors make it very difficult to reconstruct the image of the drilling area, so the performance verification must be carried out. We propose a set of methods to process LRPR’s data and reconstruct image. The verification experiments demonstrate that these methods are suitable for LRPR, the thickness and structure of the lunar regolith from zero to two meters can be clearly mapped, the vertical resolution is a few centimeters, and the electromagnetic properties of the subsurface can be estimated. Therefore, the performance of LRPR meets the requirements, and LRPR can successfully support drilling and sampling.

The Tianwen-1 of China is expected to land and explore on the planet Mars in May 2021, carrying a Mars Rover-mounted Subsurface Penetrating Radar (RoSPR) system. A VHF band ultra-wideband (UWB) monopole antenna integrated on the Mars Rover, and described in this paper, has been designed for the subsurface exploration of Mars tens of meters deep. Conventional antenna design methods usually prove difficult in taking into account several key parameters such as miniaturization, broadband characteristics and radiation efficiency. Moreover, there is almost no special research on the reliability of antennas. For this purpose, a miniaturized air-coupled monopole antenna integrated with the Mars Rover has been designed. The overall length of the antenna is 0.13 λ at the lowest operating frequency. In addition, the classical Wu–King profile is improved, which not only satisfies the operating bandwidth of the antenna, but also increases the gain by 3–4 dB. In the design, the innovative application of planar embedded resistance greatly enhances the reliability of the antenna and thereby ensures that the antenna can work on Mars for a long term. This is the first application of this antenna design method in the aerospace field. Because it is difficult to test the low-frequency antenna accurately, a 1:4 scale model of the antenna and Rover is fabricated to equivalently measure the radiation characteristics of the antenna. Furthermore, the performance and practicability of the antenna and radar system are verified on the glacier.

The unequal distribution of volcanic products between the Earth-facing lunar side and the farside is the result of a complex thermal history. To help unravel the dichotomy, for the first time a lunar landing mission (Chang’e-4, CE-4) has targeted the Moon’s farside landing on the floor of Von Kármán crater (VK) inside the South Pole-Aitken (SPA). We present the first deep subsurface stratigraphic structure based on data collected by the ground-penetrating radar (GPR) onboard the Yutu-2 rover during the initial nine months exploration phase. The radargram reveals several strata interfaces beneath the surveying path: buried ejecta is overlaid by at least four layers of distinct lava flows that probably occurred during the Imbrium Epoch, with thicknesses ranging from 12 m up to about 100 m, providing direct evidence of multiple lava-infilling events that occurred within the VK crater. The average loss tangent of mare basalts is estimated at 0.0040-0.0061., The authors here report results from the ground-penetrating radar onboard the Yutu-2 rover from the Chagn’E 4 mission. The study presents up to 330 m deep subsurface structure of the Von Karman Crater inside the South Pole Aitken Basin.

As a main payload of the lander of Chang’E-5, lunar regolith penetrating array radar (LRPR) is a multi-input and multioutput ground penetrating array radar system. The following are the main characteristics of LRPR: it works at a fixed location, the layout of the antennas is irregular, and the amount of data for imaging is very rare. A prestack depth migration imaging method based on Kirchhoff integral is presented, which overcomes the problems of irregular antenna layout and the layered medium. The issue of sparse matrix imaging for LRPR is solved successfully by the method. The laboratory experiment demonstrates that the proposed method is very suitable for LRPR imaging, in which the targets are clearly distinguished and their depths are also consistent with the reality.

Chang'E-3 was launched on December 2, 2013, and successfully landed on the moon on December 14, 2013. It carried a 140-kg lunar rover named Yutu, which is designed to explore an area of 3 km2. Chang'E-3 mission is to achieve China's first soft landing and roving on the moon [1]. Lunar penetrating radar (LPR) is a key payload of the Yutu lunar rover in the Chang'E-3 mission. The scientific target of LPR is to explore the thickness distribution of the lunar regolith and the geological structure of rock under the lunar surface. To fulfill the target, LPR is equipped with two ultrawideband antennas, channel 1 (CH1) and channel 2 (CH2). The CH1's center frequency is 60 MHz, and the CH2�s center frequency is 500 MHz. LPR, which is mounted on the Yutu rover, can sound the structure of the lunar surface in a large range and over a long distance while the rover is moving.

Lunar Regolith Penetrating Radar (LRPR) is a high resolution penetrating and imaging radar, which is a main payload of Chang'E-5. The primary aim of LRPR is to survey the lunar regolith thickness and the subsurface structure of landing area. The aim is achieved by transmitting pulse and receiving echo signal. As the width of the transmitting pulse is picosecond level, it is difficult to achieve real-times sampling of echo signal on the circuit. Equivalent sampling is adopted. The commonly used methods of equivalent sampling are implemented by the delay chip or hardware circuit. This article points out the disadvantages of the two methods, then designs a method based on the principle of Vernier Caliper. The method with strong adaptability is implemented by PLL based on FPGA, which has high reliability and high precision. There is no extra expense in hardware circuit with this method, and the delay accuracy can be adjusted.

China's first Mars probe including an orbiter and a landing rover will be launched by 2020. A subsurface penetrating radar instrument has been selected to be a part of payload on the rover. The main scientific objective of the SPR is to characterize the thickness and sub-layer distribution of the Martian soil. The SPR consists of two channels. The low frequency channel of the SPR will provide a penetrating depth of 10 to 100 meters with a resolution of a few meters within the Martian soil. The higher frequency channel will penetrate to a depth of 3 to 10 meters with a resolution of a few centimeters within the Martian soil. The engineering model of the SPR was designed and manufactured. In order to illustrate and validate the equipment's performance, some laboratory field tests have been performed. The objectives of these tests were to evaluate the interaction between the radar and the rover and detect the internal objects buried in the pool filled with artificial volcanic ash.

Lunar Regolith Penetrating Radar (LRPR) is one payload of Lander for Chang'E-5. LRPR's scientific missions are: (1) providing information support for drill and sampling device; (2) sounding lunar regolith thickness and structure below the Lander area, which is covered by radar's antenna. In order to obtain detection data effectively, it is necessary to overcome the problem that the Lander cannot move. The LRPR uses an electric scanning method to traverse 12 antennas instead of the traditional detection mode. With the method, LRPR requires only one receiver and transmitter, thereby can effectively reduce weight and power consumption. LRPR is a time domain carrier-free pulse radar, which is compose of antenna array, electronic box and RF cable. It is shown that task requirements are met by confirmatory test of simulation Lunar Regolith on the round.

Onsite radar shows what lies beneath In more active periods of the Moon's history, volcanic eruptions created lava plains that formed layers of dark basalt. Without subsurface probing, we can only examine the most recent flows. After the soft landing of the Chang'E-3 spacecraft, Xiao et al. made penetrating radar measurements of the lunar crust with the Yutu rover. Several subsurface layers suggest multiple geologic processes at play throughout the crustal history, including multiple lava flows and the weathering-induced creation of dust and rocky debris. Science , this issue p. 1226

Lunar Penetrating Radar (LPR) is one of the important scientific instruments onboard the Chang'e-3 spacecraft. Its scientific goals are the mapping of lunar regolith and detection of subsurface geologic structures. This paper describes the goals of the mission, as well as the basic principles, design, composition and achievements of the LPR. Finally, experiments on a glacier and the lunar surface are analyzed.

Lunar Regolith Penetrating Radar (LRPR) is a high resolution penetrating and imaging radar, which is a main payload onboard the detector of Chang'E-5. It is mounted on the bottom of the detector of Chang'E-5 and its main task is to survey the lunar regolith thickness and subsurface structure of landing domain. Because the detector is static, LRPR has to work only in stationary condition and is designed as a multi-input and multi-output ground penetrating radar system, employing an antenna array including 12 off-ground Vivaldi antennas as transmitters or receivers. When one serves as the transmitter antenna, the others are as the receiver antennas, in turn, to complete all scan probe task. During the development of the equipment, the detection capability and the imaging method of processing the dataset must be verified on the ground. A multi-offset diffraction stack migration algorithm to process LRPR dataset for obtaining a high resolution image of detect domain is developed on this paper. The results of ground verification demonstrate that the multi-offset diffraction stack migration algorithm can be applied to process LRPR dataset, and LRPR meets the design specifications: detecting depth over 2m, and detecting resolution better than 5 cm in lunar regolith.

China's Mars probe including an orbiter and a landing rover will be launched by 2020. A subsurface penetrating radar (SPR) instrument has been selected to be a part of the payload on the rover. The main scientific objective of the SPR is to characterize the thickness and sub-layer distribution of the Martian soil. The SPR consists of two channels. The low frequency channel of the SPR will provide a penetration depth of 10 to 100 meters with a resolution of a few meters within the Martian soil. The higher frequency channel will penetrate to a depth of 3 to 10 meters with a resolution of a few centimeters within the Martian soil. The SPR first version prototype was designed and some field tests have been conducted with it.