# Sentence-Level Insights from the Martian Literature: A Natural Language Processing Approach
## 3 Results
### Sentiment Analysis  
Figure 6 highlights the positive emotions in Mars research across multiple domains, including geological evolution, atmospheric dynamics, water resource distribution, and meteorite genesis analysis. These advances reflect the significant contributions of recent exploration missions and modeling studies in uncovering Mars' evolutionary processes, reconstructing ancient environments, and assessing its potential habitability. Collectively, these findings not only enhance our understanding of multi-layer interactions on Mars but also establish a scientific foundation for future high-precision exploration missions. In contrast, Figure 6b highlights the core scientific challenges that remain unresolved in Mars research, reflecting the limitations and uncertainties within the current understanding framework. These negative sentiment expressions reveal persistent difficulties faced by researchers in reconstructing early Martian climate conditions, explaining variations in atmospheric trace gases, evaluating the stability of liquid water, and predicting the effects of space radiation. Such challenges not only constrain a systematic understanding of Martian geological and climatic history but also pose significant obstacles to future crewed exploration and sample return missions. In the study of Martian solid crust, remote sensing data and in situ geochemical analyses have significantly advanced our understanding of the planet's internal structure and geological evolution. High-resolution terrain and spectral datasets have supported modeling efforts related to crust-mantle differentiation, volcanic activity, and localized thermal anomalies. In particular, Martian meteorites, as ground truth samples, provide critical evidence for constraining mantle composition and volcanic processes. However, substantial gaps remain. Some early plate tectonic models are inconsistent with observed crustal thickness and surface geochemical characteristics, and the correlation between Martian surface compositions and meteorite types remains unclear. These issues reflect dual challenges: limited representativeness of available samples and an incomplete under  
Figure 5: In-depth thematic simulation of the top ten clusters identified in Figure 3. Panel (**a**) presents the simulation of ten sub-themes within Cluster 1, including corresponding word clouds and GPT-4o-generated summaries. Similarly, Panels (**b–j**) represent Clusters 2 to 10. Each theme is accompanied by a word cloud and a concise summary generated using GPT-4o. standing of crustal differentiation mechanisms. Addressing these challenges will require the advancement of integrated modeling approaches. In the study of the Martian surface, exploration of the Martian surface has revealed abundant evidence of ancient water activity, including river valley networks, sedimentary bedding, and water-altered minerals, supporting the view that early Mars once possessed a habitable environment. The combined observations from orbital platforms and rovers have enabled the reconstruction of ancient hydrological processes, significantly enriching our understanding of early surface topography and sedimentary systems. However, the modern Martian surface presents several challenges. Under current low-pressure and low-temperature conditions, the stable existence of liquid water is highly unlikely, creating a marked inconsistency with geographic evidence. Moreover, the presence of surface oxidants, intense ultraviolet radiation, and frequent dust storms not only inhibits the preservation of organic matter but also poses significant risks to lander systems and future human exploration. This contrast between positive findings and ongoing challenges highlights the dramatic transition of the Martian surface from a potentially habitable early environment to its current harsh and inhospitable state.