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.

Tail rotor failure represents a critical emergency in helicopter flight operations. Conventional recovery mandates an immediate engine shutdown and transition to autorotation, significantly compromising both mission survivability and operational flexibility. To achieve stable powered flight, this paper establishes a yaw stability strategy integrating vertical tail side-force control with active main rotor torque suppression. This strategy employs controlled sideslip to generate a yaw-restoring moment from the vertical tail and an increased descent rate to reduce rotor power requirement. These two effects act in concert to counteract the rotor torque. Trim analysis of a representative helicopter in a tail rotor failure condition validates the strategy. Two yaw control architectures are developed for the failure operation: (1) a cascade loop comprising yaw angle, yaw rate, lateral velocity, and roll angle, and (2) the latter omitting lateral velocity. Comparative simulations demonstrate that although Loop (1) yields slower yaw convergence than Loop (2), it delivers enhanced stability. Furthermore, an emergency control trajectory tailored for moderate forward velocity is proposed. The trajectory initiates with a controlled descent-rate increase to arrest yaw divergence. The forward velocity is then augmented to mitigate sideslip, and the descent rate is gradually reduced, ensuring adequate altitude clearance over the landing zone. This study provides a strategy for enabling powered flight under tail rotor failure conditions.