Mars is increasingly considered for colonization by virtue of its Earth-like conditions and potential to harbor life. Responding to challenges of the Martian environment and the complexity of transporting resources from Earth, this study develops a novel geopolymer-based high-performance Martian concrete (HPMC) using Martian soil simulant. The optimal simulant addition, ranging from 30% to 70% of the total mass of the binders, was explored to optimize both the performance of HPMC and its cost-effectiveness. Additionally, the effects of temperature (-20 degrees C-40 degrees C) and atmospheric (ambient and carbonated) curing conditions, as well as steel fibre addition, were investigated on its long-term compressive and microstructural performance. Optimal results showed that HPMC with 50% regolith simulant achieved the best 7-day compressive strength (62.8 MPa) and the remarkable efficiency improvement, a result of ideal chemical ratios and effective geopolymerization reaction. Under various temperature conditions, sub-zero temperatures (-20 degrees C and 0 degrees C) diminished strength due to reduced aluminosilicate dissolution and gel formation. In contrast, specimens cured at 40 degrees C and 20 degrees C, respectively, showed superior early and long-term strengths, with the 40 degrees C potential for moisture loss related shrinkage cracking and reduced geopolymerization. Regarding the atmospheric environment, carbonation curing and steel fibre addition both improved the matrix compactness and compressive strength, with carbon-cured fibre-reinforced HPMC achieving 98.3 MPa after 60 days. However, long-term exposure to high levels of CO2 eventually reduced the fibres' toughening effect and caused visible damages on steel fibres.

The ultimate goal of Mars exploration is to construct a Mars base. In particular, it is necessary to prepare fibres by using Martian soil as a raw material. High-strength Martian glass fibres can be used to reinforce composite materials to meet the requirements of high-strength functional materials in base construction. Owing to the wide variation in MgO content in Martian soil, in this study, the effects of MgO on the structure, strength and acid resistance of Martian glass and glass fibres were investigated. The preparation conditions and mechanical properties of simulated Martian soil fibre (SMSF) were studied via DSC, XRD, Raman, NMR, FT-IR and hightemperature rotational viscometry. The corrosion behaviour of MgO-SMSF in H2SO4 solution was subsequently studied via SEM/EDS. The results showed that MgO reduces the spinnability window and prevents the fibres from stretching continuously, and a threshold appears to exist at 10.89 % MgO. The viscosity of the melt decreased significantly, and the crystallization trend increased with MgO above the threshold. The fibre tensile strength showed a nonlinear relationship with a 22.85 % increase in the fibre tensile strength at 9.24 % MgO. SEM/EDS revealed that the surface of the SMSF formed a gel layer, and the mass retention of the MgO-SMSF in the H2SO4 solution reached 90.17 %. The corrosion of SMSF under acidic conditions was controlled by ion diffusion, with Mg+ and Ca+ diffusing to the fibre surface, resulting in nonuniform corrosion. Raman-based statistical structure-property modelling further explains the impact of MgO-induced structural changes on the tensile strength and elastic modulus, with good agreement between the model predictions and measured values.

In the actively evolving research of Mars in recent decades, a special place is occupied by landers and rovers. The diversity of landscapes and soils on Mars, characteristic of terrestrial planets with an atmosphere, makes the development of soil simulators relevant for each new type of terrain in the area of a potential landing site. In the article, based on a comprehensive analysis of the physical and mechanical properties of soils at previous landing sites and a geomorphological analysis of the Oxia Planum plain, the main requirements for the properties of Martian soil analog at the landing site of the ExoMars Rosalind Franklin Mission (RFM) were determined. Readily available technogenic and natural materials have been selected and experimentally justified as components for creating a Martian soil analogue. A methodology for creating the soil analog is presented, and its physical and mechanical properties are measured. The developed Martian soil analog VI-M1 is actively used for large-scale natural experiments, including drop tests of spacecraft in the ExoMars series.

After landing in the Utopia Planitia, Tianwen-1 formed the deepest landing crater on Mars, approximately 40 cm deep, exposing precious information about the mechanical properties of Martian soil. We established numerical models for the plume-surface interaction (PSI) and the crater formation based on Computational Fluid Dynamics (CFD) methods and the erosion model modified from Roberts' Theory. Comparative studies of cases were conducted with different nozzle heights and soil mechanical properties. The increase in cohesion and internal friction angle leads to a decrease in erosion rate and maximum crater depth, with the cohesion having a greater impact. The influence of the nozzle height is not clear, as it interacts with the position of the Shock Diamond to jointly control the erosion process. Furthermore, we categorized the evolution of landing craters into the dispersive and the concentrated erosion modes based on the morphological characteristics. Finally, we estimated the upper limits of the Martian soil's mechanical properties near Tianwen-1 landing site, with the cohesion ranging from 2612 to 2042 Pa and internal friction angle from 25 degrees to 41 degrees. (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/).