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日益增长的太空碎片为载人空间站和卫星带来严重的安全挑战。2011年,NASA提出使用地面连续激光照射空间碎片,利用其微弱的光压力效应,通过长期积累,改变其轨道,从而预防其与航天器可能的碰撞。这一碰撞避免方法并不把太空碎片拉回大气层内,而是防止碰撞,由于不需要航天器机动,且光压的温和作用也对激光器发射功率没有太高要求,因此这种避碰方法受到广泛关注。然而,该方法的提出者采用的迎面照射控制律尽管简单但非最优,故需要设计最优控制律。通过建立两点边值问题模型,以两物体之间距离的最大化为控制目标,求解了最优性条件。仿真显示,经优化后控制律的避碰效果提高程度非常显著,提高幅度与初轨有关,通常为25%~125%。
The growing space debris pose serious security challenges for manned space stations and satellites. In 2011, NASA proposed to use ground continuous laser to irradiate space debris and use its weak light pressure effect to change its orbit by long-term accumulation and thereby prevent possible collision with spacecraft. This method of collision avoidance does not pull space debris back into the atmosphere but rather prevents collisions. This method of collision avoidance is limited by the fact that the spacecraft maneuver is not required and the mild effects of light pressure do not place too much on the laser launch power extensive attention. However, the oncoming exposure control law adopted by the proponents of this method, though simple but not optimal, requires the design of an optimal control law. By establishing a two-point boundary value problem model and taking the maximization of the distance between two objects as the control objective, the optimality condition is solved. The simulation results show that the improved anti-collision effect of the control law is very significant, and the improvement is related to the initial track, usually from 25% to 125%.