Wind disturbances in the thin Martian are highly stochastic and spatially correlated, posing significant challenges to rotorcraft flight safety. Meanwhile, limited onboard computational resources make real-time safe trajectory planning difficult. This paper proposes a trajectory planning and analysis framework based on composite wind modeling and differential flatness theory. The proposed method decouples deterministic trajectory generation from stochastic robustness evaluation, enabling efficient trajectory planning in uncertain wind environments with planning-stage robustness evaluation. First, a composite wind model is constructed by combining multi-scale decomposition with Gaussian process regression, where a local kernel strategy is introduced to improve computational efficiency. Second, based on differential flatness theory and the MinCo method, a high-order polynomial trajectory is formulated. A multi-dimensional cost function is designed under wind field constraints to generate a nominal trajectory, incorporating trajectory smoothness, flight time, energy consumption, risk avoidance, and state feasibility. Finally, wind uncertainty is propagated via Monte Carlo sampling, and trajectory performance is quantitatively evaluated. Simulation results show the proposed method can generate safe, feasible, and risk-aware trajectories under the uncertain Martian wind conditions. Across all test scenarios, the mean terminal deviation, average deviation, and maximum deviation remain within 2.1%, 1.6%, and 3.6% of the trajectory length, respectively, indicating strong robustness in the evaluated scenarios.

Due to the distinct atmospheric conditions, there are notable differences in the rotor aerodynamic characteristics between the Mars helicopters and conventional Earth helicopters. Determining the flight dynamics characteristics of the Mars helicopter presents considerable challenges. This study focuses on a coaxial helicopter as the research subject, specifically analyzing the flapping characteristics of rotor blades in the unique Martian atmospheric environment. The unsteady aerodynamic loads and wake effects on the rotor are calculated utilizing the viscous vortex particle method. Furthermore, the aerodynamic interference of the coaxial dual-rotor system is analyzed across a range of forward flight speeds. Subsequently, a novel and efficient trimming method based on a combination of the viscous vortex particle method and dynamic inflow model for Mars helicopters is proposed to enhance the calculation accuracy and computational efficiency. Moreover, a relaxation factor is introduced to modify the induced velocities at various positions on the rotor disk. Finally, a comprehensive flight dynamics analysis is carried out for the Mars coaxial helicopter. And the results indicate that during the forward flight of the Mars helicopter, the rotors generate noticeable aerodynamic disturbances and there is evident coupling among control channels, with Dutch roll mode and velocity-attitude stability exhibiting dynamic instability as flight speed increases, posing challenges for the design of the flight control system.