近地小行星探测转移轨道方案设计与优化

探测小行星转移轨道的设计不同于传统的飞行器轨道设计,由于需要更多的能量,仅依靠冲量轨道转移难于实现,针对此问题,以近地小行星3288 Seleucus为例,采用了先将飞行器递推至以2 a为周期的日心大椭圆轨道的远日点,加深空机动使之再次与地球相遇,进行借力飞行的轨道转移技术,设计了其转移轨道.为了进一步减少此探测任务在轨道转移方面所需的总的能量,采用了变分与主矢量原理推导出了总的速度增量对自由变量的偏导数,把复杂的多维非线性轨道优化问题归结为一个多维参数优化问题,并利用梯度下降法,对所设计的探测3288 Seleucus小行星的转移轨道方案进行了优化.数学仿真结果表明:这种地球借力飞行的轨道转移技术可有效的降低完成任务所需的总能量,特别是发射时所需的能量.

Design and optimize scheme of transfer trajectory for near Earth asteroid exploration mission

Designing transfer trajectory for exploration asteroid mission is different from conventional orbit design due to requiring more energy.So it is difficult to realize exploring mission only using impulse direct transfer trajectory.For this problem,taking the 3288 Seleucus asteroid as an example,the transfer trajectory technology of the Earth gravity assist with deep space maneuver is used to design transfer trajectory for exploring near Earth asteroid mission.In order to design Earth gravity assist transfer trajectory,spacecraft is propagated to aphelion of elliptical orbits with 2-years period and then spacecraft return to Earth for swing-by by means of putting on deep space maneuver.To reduce the total velocity increments further,analytic first derivatives are derived using the variation and primer vector theory,then the complicated multi-dimensions nonlinear optimal problem is transformed into parameter optimal problem.The transfer trajectory profiles for exploring Seleucus asteroid is optimized using qusi-Newton algorithm.The numerical calculation indicates that the design method of the Earth gravity assist with deep space maneuver can effectively reduce total velocity increments requirements,especially launch energy requirements.