Enhancing carbon emission mitigation and carbon utilization have become necessary for the world to respond to climate change caused by the increase of greenhouse gas concentrations. As a result, carbon capture, utilization, and storage (CCUS) technologies have attracted considerable attention worldwide, especially in China, which plans to achieve a carbon peak before 2030 and carbon neutrality before 2060. This paper proposed six priorities for China, the current world’s largest carbon emitter, to achieve its dual carbon strategy in the green energy transition process. We analyzed and summarized the challenges and potentialities of conventional carbon utilization (CU), carbon capture utilization (CCU), and CCUS. Based on the current development trend, carbon dioxide capture, circular utilization, and storage (CCCUS) technology that integrates carbon circular utilization and partial sequestration, with large-scale underground energy storage were proposed, namely biomethanation. Technically and economically, biomethanation was believed to have an essential contribution to China’s renewable energy utilization and storage, as well as the carbon circular economy. The preliminary investigation reveals significant potential, with a corresponding carbon storage capacity of 5.94 × 10⁸ t~7.98 × 10⁸ t and energy storage of 3.29 × 10¹² kWh~4.42 × 10¹² kWh. Therefore, we believe that in addition to vigorously developing classical CCUS technology, technical research and pilot projects of CCCUS technology that combined large-scale underground energy storage also need to be carried out to complete the technical reserve and the dual-carbon target.

This study explored underground biomethanation as a means to achieve carbon neutrality and promote carbon circular utilization by methanating CO₂ and hydrogen-rich industrial waste gas in depleted natural gas reservoirs (MECHIG). This approach not only aids the development of carbon capture, utilization, and storage (CCUS) technologies, but also effectively processes industrial waste gas, thereby reducing pollutant emissions. In order to verify the feasibility of the MECHIG concept, this study builds upon the analysis of the MECHIG process overview and employs the net present value (NPV) analysis method to investigate its economic viability. Additionally, the study conducts a sensitivity analysis on six factors, namely methanation efficiency, facility site investment, hydrogen content in waste gas, natural gas prices, operation and maintenance (O&M) investment, and CO₂ capture and injection prices. The results indicate the following: (1) Under the baseline scenario, the NPV of the MECHIG concept is approximately CNY 5,035,100, which suggests that the concept may be economically viable. (2) The fluctuation in natural gas prices has the most significant impact on NPV, followed by facility site investment and methanation efficiency. In contrast, the variations in hydrogen content in waste gas, O&M investment, and CO₂ capture and injection prices have relatively smaller effects on NPV. (3) To ensure the economic feasibility of the concept, the acceptable fluctuation ranges for the factors of methanation efficiency, facility site investment, hydrogen content in waste gas, natural gas prices, O&M investment, and CO₂ capture and injection prices are −16.78%, 5.44%, −32.14%, −4.70%, 14.86%, and 18.56%, respectively.

Initial excavation-induced damage may alter water-driven weakening and failure in bedded shale, yet direct experimental evidence from comparable loading–hydration routes remains limited. In this study, uniaxial compression tests with acoustic emission (AE) monitoring were conducted on bedded shale from the Longmaxi Formation in the Sichuan Basin, China, under two routes, i.e., direct saturation (DS) and pre-damage followed by saturation (PDRS), across seven bedding orientations from 0° to 90°. Pre-damage was introduced by loading–unloading to 0.6 of the orientation-dependent peak strength, producing measurable defects and reducing P-wave velocity by an average of 1.23% while preserving the overall anisotropic pattern of wave propagation. Compared with DS, PDRS caused clear mechanical deterioration, with mean reductions of 37.63% in peak strength and 31.14% in elastic modulus. Both routes retained pronounced bedding-angle dependence, although the locations of minimum strength and stiffness differed between them. AE activity in the PDRS group generally initiated earlier and accumulated more persistently before peak stress. RA–AF analysis showed that tensile-like cracking dominated across all bedding orientations in PDRS, whereas the DS group exhibited stronger orientation-dependent variation in cracking mode. The b-value range was also narrower in PDRS than in DS, indicating reduced dispersion of event-size statistics among orientations. Macroscopically, failure evolved from more distributed multi-crack and mixed-mode patterns in DS to more localized dominant-fracture failure with reduced branching in PDRS. Overall, the results suggest that pre-damage before saturation changes the subsequent weakening and fracture development of bedded shale during reloading.

Deep‐space exploration requires reliable mechanical constraints for lunar materials; however, the scarcity of samples limits destructive macroscale testing. Here, we combine automated mineralogical analysis and nanoindentation to investigate the mineral‐scale mechanical behavior of two Chang'e‐5 regolith particles and a Laâyoune 002 feldspathic breccia comparison sample. Rather than treating these materials as bulk proxies for all mare and highland regolith regions, we compare analogous mineral domains using an identical testing protocol. Minerals in the Chang'e‐5 particles generally show lower elastic modulus and hardness, greater indentation depth and creep displacement, and higher plastic work ratios than analogous minerals measured in the interior polished section of Laâyoune 002. The strongest contrast occurs in ilmenite, where more plastic, energy‐dissipative deformation is observed. These measured contrasts document micromechanical differences among analogous minerals in the analyzed lunar samples. Their interpretation considers lithology, mineral chemistry, local microstructure, and impact history, with regolith processes and space‐weathering overprint as plausible contributors to the Chang'e‐5 response. First‐order homogenization of the analyzed particle‐scale assemblages yields equivalent elastic moduli of about 54 GPa for the Chang'e‐5 assemblage and about 78 GPa for the Laâyoune 002 assemblage. These results provide mineral‐resolved mechanical constraints for interpreting lunar material evolution and for designing better simulants, experiments, and multiscale engineering assessments.

The present study investigates possible evidence for an underground cavity on the western flank of Elysium Mons, initially identified in the Mars Cave Catalog, which is interpreted as a potential subsurface lava tube skylight. Using a multi-sensing approach, we analyze a Potential Cave Candidate (PCC) that emerges as a promising target for future missions, offering insights into Martian subsurface processes, resource potential, and astrobiological prospects. In particular, CTX and HiRISE imagery from the Mars Reconnaissance Orbiter, captured under varying solar illumination angles, reveal an elliptical morphology with persistent shadowed regions and roof collapse features, indicating depth and potential subterranean connectivity. HiRISE imagery further identifies a possible cave entrance suitable for future robotic exploration. Thermal data from the Mars Odyssey's THEMIS instrument indicate nocturnal thermal anomalies, supporting subsurface continuity. Topographic profiles derived from the Mars Global Surveyor’s MOLA data provide precise elevation measurements, reinforcing the hypothesis of an underground cavity.Additionally, TES mineralogical analysis identifies K-feldspar, plagioclase, amphibole, sulfates, carbonates, sheet silicates, high-silicon glass, and surface dust, indicative of volcanic processes and past water activity. These findings inform the proposed location of a landing site and an optimized robotic exploration path, emphasizing the potential use of AI-driven robotic dogs. These advanced systems combine AI-driven mobility, LiDAR-based mapping, and autonomous decision-making to navigate challenging terrains, including crater walls and potential cave entrances. Integrating such technology into planetary in situ exploration could overcome the limitations of traditional rovers, enhancing in situ analysis and advancing the search for habitable environments and biosignatures on Mars. This research has critical implications for the first extraterrestrial cave exploration, China's first Mars cave mission, and the broader quest for liquid water and potential extraterrestrial life, representing a transformative milestone in planetary exploration.