In situ resource utilization of lunar regolith provides a cost-effective way to construct the lunar base. The melting and solidifying of lunar soil, especially under the vacuum environment on the Moon, are the fundamentals to achieve this. In this paper, lunar regolith simulant was melted and solidified at different temperatures under a vacuum, and the solidified samples' morphology, structure, and mechanical properties were studied. The results indicated that the density, compressive strength, and Vickers hardness of the solidified samples increased with increasing melting temperature. Notably, the sample solidified at 1400 degrees C showed excellent nanohardness and thermal conductivity originating from the denser atomic structure. It was also observed that the melt migrated upward along the container wall under the vacuum and formed a coating layer on the substrate caused by the Marangoni effect. The above results proved the feasibility of employing the solidified lunar regolith as a primary building material for lunar base construction.

The development and utilization of lunar resources are entering a critical stage. Immediate focus is needed on key technologies for in-situ resource utilization (ISRU) and lunar base construction. This paper comparatively analyzes the basic characteristics of lunar regolith samples returned from Chang'e-5 (CE- 5), Apollo, and Luna missions, focusing on their physical, mechanical, mineral, chemical, and morphological parameters. Given the limited availability of lunar regolith, more than 50 lunar regolith simulants are summarized. The differences between lunar regolith and simulants concerning these parameters are discussed. To facilitate the construction of lunar bases, this article summarizes the advancements in research on construction materials derived from lunar regolith simulants. Based on statistical results, lunar regolith simulant-based composites are classified into 5 types by their strengthening and toughening mechanisms, and a comprehensive analysis of molding methods, preparation conditions, and mechanical properties is conducted. Furthermore, the potential lunar base construction forms are reviewed, and the adaptability of lunar regolith simulant-based composites and lunar base construction methods are proposed. The key demands of lunar bases constructed with lunar regolith-based composites are discussed, including energy demand, in-situ buildability, service performance, and structural availability. This progress contributes to providing essential material and methodological support for future lunar construction. (c) 2024 Published by Elsevier B.V. on behalf of China University of Mining & Technology. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).