# Sentence-Level Insights from the Martian Literature: A Natural Language Processing Approach
## 3 Results
### Unsupervised Clustering
Research on the Martian atmosphere has focused on its structural characteristics, compositional evolution, and escape mechanisms, highlighting its critical role in the planet's climate history and assessments of past habitability. Since 2001, atmospheric studies have been steadily expanded, consistently occupying major research directions across multiple periods. From 2001 to 2005, investigations based on orbital missions such as MGS and Mars Odyssey established a preliminary understanding of temperature distribution, vertical dust structure, and high-tide phenomena, laying the foundation for characterizing Martian atmospheric circulation. Between 2006 and 2010, the research focus shifted to the coupling processes between the atmosphere and dust storms, utilizing climate models and multi-mission observations to explore circulation disturbances, thermal structure evolution, and their feedback on seasonal climate cycles. From 2011 to 2015, the Mars Atmosphere and Volatile Evolution (MAVEN) mission enabled detailed investigations of middle and upper atmosphere escape mechanisms, systematically measuring ion composition and escape fluxes, and clarifying the role of solar wind and electromagnetic interactions in atmospheric loss. Between 2016 and 2020, attention turned to modeling the long-term evolution and escape history of the Martian atmosphere, exploring the impacts of CO\({}_{2}\) and H\({}_{2}\)O loss on paleoclimate conditions and atmospheric thinning, and proposing a transition pathway from a dense, warm climate to the current thin, cold state. From 2021 to 2024, research focused on the spatiotemporal evolution of atmospheric structural disturbances and escape responses induced by global dust storms. By integrating multi-source data from MAVEN and the Exobiology on Mars (ExoMars) program, studies achieved high-resolution characterizations of thermospheric dynamics, ionospheric disturbances, and energy input processes. Overall, research on the Martian atmosphere has evolved from static structural mapping to dynamic process analysis, advancing a comprehensive understanding of the multi-layer interactions that govern the evolution of Martian climate and atmospheric escape history. Research on the Martian space focuses on the interactions between the solar wind, interplanetary magnetic field, and the Martian ionosphere-magnetosphere system, revealing the planet's atypical magnetospheric structure and atmospheric escape processes in the absence of a global intrinsic magnetic field. Since 2006, studies in this area have shown a continuous trend of deepening. From 2006 to 2010, research preliminarily identified the basic configuration of the induced magnetosphere, emphasizing the regulatory role of crustal magnetic fields on ionospheric structure and plasma boundaries. Between 2011 and 2015, advancements in theoretical modeling and the accumulation of orbital observations shifted the focus to the influence of solar wind dynamic pressure variations on the topology of the Martian magnetosphere, clarifying the shielding and guiding functions of crustal magnetic fields in plasma transport. From 2016 to 2020, data from the MAVEN mission supported in-depth analysis of energy-mass coupling mechanisms between magnetic fields and escaping ions, revealing that changes in solar activity cycles modulate atmospheric escape rates by influencing external energy inputs and magnetic field configurations. Between 2021 and 2024, research focused on high-resolution analyses of plasma disturbances and energy deposition, elucidating the regulatory pathways through which solar wind-magnetosphere interactions drive neutral atmospheric escape and emphasizing the overall coupling mechanisms across the ionosphere, magnetosphere, and escape processes. Overall, research on the Martian space environment has progressively transitioned from early structural identification to dynamic modeling of multi-scale, multi-layer coupling processes, reflecting a shift from descriptive studies to mechanistic understanding.