Seepage is a common disease of earth and rock embankment dams, but due to the complex geological conditions, its location and seepage diameter are more difficult to be accurately detected. In order to accurately determine the seepage damage state of earth and rock dam materials during the evolution of seepage field, and to clarify the change rule of three-dimensional electric field of earth and rock embankment dams during the evolution of seepage field, this paper establishes a correlation model between seepage field and electric field based on porosity. Based on the model, the relationship between resistivity and critical hydraulic ratio drop during the infiltration damage of soil and rock dam is determined, focusing on the study of the three-dimensional electric field in the infiltration process of soil and rock dam body with the seepage field change characteristics and change rules, and obtaining the electric field response characteristics of the seepage field of the different hidden bodies, which provides a diagnostic basis for the realization of the subsequent leakage diagnostic technology of soil and rock dams.

Facing the challenges of in-situ utilization of lunar regolith resources, applying an external electric field to manipulate lunar particles has become a promising method for space particle control, which mainly depends on the particle charging properties in the applied electric field. Using the surficial lunar regolith samples brought back from the Moon by the Chang'e-5 mission (CE5 LS), this work successively studied their charging properties, particle dynamics, and their collision damages to aerospace materials under the action of an external electric field in high-vacuum conditions. The results indicated that the charging process and electrostatic projection of lunar regolith particles under high-vacuum conditions were different from those under atmosphere conditions. The particle diameter range of CE5 LS used in the experiment is 27.7-139.0 lm. For electric field strength of 3-12 kV cm-1, the charge obtained by CE5 LS is 4.8 x 10-15- 4.7 x 10-13 C and the charge-to-mass ratio is 1.2 x 10-5-6.8 x 10-4 C kg-1. The CE5 LS is easier to be negatively charged in an external electric field. Furthermore, significant damages were observed on the target impact surfaces, indicating severe influences of lunar regolith particles on aerospace materials. Our work contributes to a more comprehensive understanding of physical mechanisms controlling the lunar regolith shielding and utilization, and will inspire broad efforts to develop the lunar in-situ engineering solutions. (c) 2024 THE AUTHORS. Published by Elsevier LTD on behalf of Chinese Academy of Engineering and Higher Education Press Limited Company. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).

Lunar polar volatiles, such as water ice, are essential lunar exploration objects. The conceptual design for China's Chang'E-7 lunar exploration mission to the South Pole was proposed. The mission comprises an orbiter, a lander, a rover, a leaper, and a relay satellite. The orbiter can provide high-resolution images to select a suitable landing site. The rover and leaper will be deployed for in-situ exploration in sunlit areas and permanently shadowed regions, respectively. The relay satellite will transmit all data to the ground. We calculated the accumulated illumination, as an engineering condition, within a 15 kmx15 km area partially covering the Shackleton crater from January 1, 2024, to December 31, 2026. Two potential landing sites-areas SR1 and CR1-were analyzed in detail by comparing their average illumination rate, slope, and distance to the exploration target. Additionally, we simulated the electric field of the Shackleton crater within a 37 kmx27 km area, considering the effect of the plasma wake on the electric field in shadowed areas. The results show that the maximum surface potential near the rims is less than 2.1 V, while the minimum surface potential at the bottom of the crater can reach as low as -500 V due to the plasma wake effect. Therefore, a risk assessment is necessary, especially for the exploration of the leaper at the bottom of the Shackleton crater.

The existence of water (ice) has been discovered in the polar regions of the Moon, and it is expected to be used to support life for astronauts and to provide the raw material of hydrogen and oxygen. Because the exact location of ice, including the depth from the lunar surface, chemical and physical forms, and the amount of water, is unclear, the Japan Aerospace Exploration Agency (JAXA) is planning to search for ice directly by operating an uncrewed rover on the Moon. A long drill, approximately 1.5 m long, will be screwed in the regolith layer, and regolith mixed with ice will be captured and transported from the lower deep portion of the regolith layer to chemical and physical analyzers mounted on the rover. A long-range technology for vertical ice transport is indispensable for ice exploration. To this end an electrodynamic sampling system that can transport crushed ice particles vertically up to the 1.5-m height is developed. Parallel ring electrodes were attached to a collection tube, and four-phase rectangular wave high voltage was applied to the electrodes to form an electrodynamic traveling wave. Ice particles were transported upward synchronized to the traveling wave. It was demonstrated that this system could be used to capture and transport crushed ice particles, as well as regolith particles. Performance in the lunar environment (1/6-G and absence of air drag) was evaluated by the numerical calculation based on the modified discrete-element method.

NASA's two spacecraft ARTEMIS mission will address both heliospheric and planetary research questions, first while in orbit about the Earth with the Moon and subsequently while in orbit about the Moon. Heliospheric topics include the structure of the Earth's magnetotail; reconnection, particle acceleration, and turbulence in the Earth's magnetosphere, at the bow shock, and in the solar wind; and the formation and structure of the lunar wake. Planetary topics include the lunar exosphere and its relationship to the composition of the lunar surface, the effects of electric fields on dust in the exosphere, internal structure of the Moon, and the lunar crustal magnetic field. This paper describes the expected contributions of ARTEMIS to these baseline scientific objectives.