AI 中文总结
针对近地小行星防御，本文提出向阳衍射帆H反转撞击方案，其一级策略比传统反射帆撞击速度提升21%、时长缩短35%，二级策略可额外提升9km/s撞击速度，建立了应急行星防御框架。
AI 中文摘要
近地小行星威胁日益增长，行星防御是抵御灾难性灾害的重要屏障。利用太阳帆的角动量反转（H反转）轨迹进行动能撞击是极具优势的防御方案，但传统反射帆（RS）在该机动中受姿态-推力耦合限制，且横向加速所需的高锥角会降低太阳辐射压力的利用率。为提升撞击性能并简化控制，本文提出采用向阳衍射帆（SFDS）的H反转撞击方案，分别基于一级衍射角θ_d策略和二级θ_d策略开展研究。利用速端图法绘制了两种策略的可行参数空间，基于可行性分析建立了对应的定制化轨迹设计方法。以Apophis小行星撞击场景为研究对象，构建了相应的轨迹。仿真结果显示，一级θ_d SFDS相比RS，撞击速度提升21%，任务时长缩短35%；二级θ_d策略可使撞击速度额外提升9km/s。本研究通过采用SFDS H反转轨迹，建立了具备快速响应和高动能特征的应急行星防御框架。
英文摘要
With the growing threat of near-Earth asteroid, planetary defense serves as a vital shield against catastrophic disasters. Kinetic impact utilizing an angular momentum reversal (H-reversal) trajectory of a solar sail is a highly advantageous defense approach. However, traditional reflective sails (RS) are constrained during these maneuvers by attitude-thrust coupling and a degradation of solar radiation pressure utilization at the high cone angles required for transverse acceleration. To enhance impact performance and simplify control, this paper proposes an H-reversal impact scheme utilizing a Sun-facing diffractive sail (SFDS) under a one-stage diffraction angle θd strategy and a two-stage θd strategy. The feasible parameter spaces for both strategies were mapped using the hodograph method. Tailored trajectory design methods were established for both strategies based on the feasibility analysis. Apophis impact scenario was considered, and the corresponding trajectories were constructed. Simulations demonstrate that the one-stage θd SFDS outperforms RS through a 21% increase in the impact velocity and a 35% decrease in the mission duration. Furthermore, the proposed two-stage θd strategy yields an additional 9km/s gain in impact velocity. By utilizing SFDS H-reversal trajectories, this research establishes an emergency planetary defense framework characterized by rapid response and high kinetic energy.
