基于不变流形的登月轨道设计

研究了基于三体问题的不变流形设计低成本登月轨道的问题．考虑了黄道面和白道面之间夹角不为零的三维情况,将太阳-地球-月亮-卫星组成的四体问题分解成由太阳-地球-卫星和地球-月亮-卫星组成的非共面的两个限制三体问题．给出了这两个三体系统Halo轨道不变流形与两轨道面相交处进行小的变轨来设计低成本探月轨道的一般方法．比较结果表明用该方法设计的轨道比传统的Hohmann变轨节省约20%的燃料．从轨道能量的角度分析了用流形设计轨道比Hohmann变轨节省燃料的原因,并给出了理论表达式．该方法对于深空探测轨道设计的能量分析具有普遍的适用性,可为设计提供一个选择参数的标准．     

Formation around planetary displaced orbit

The paper investigates the relative motion around the planetary displaced orbit. Several kinds of displaced orbits for geocentric and martian cases were discussed. First, the relative motion was linearized around the displaced orbits. Then, two semi-natural control laws were investigated for each kind of orbit and the stable regions were obtained for each case. One of the two control laws is the passive control law that is very attractive for engineering practice. However, the two control laws are not very suitable for the Martian mission. Another special semi-natural control law is designed based on the requirement of the Martian mission. The results show that large stable regions exist for the control law.     

太阳帆日心悬浮轨道附近的相对运动

研究悬浮轨道附近的编队飞行问题，推导了悬浮轨道附近的相 对运动方程. 由于编队太阳帆之间的距离与帆到太阳的距离的比值为小量，将相对运动方程 在悬浮轨道附近线性化，得到了线性化方程. 基于该线性化方程，考虑了悬浮轨道附近的几 种编队控制方法，只需通过调节太阳帆的姿态来进行简单的控制. 其中包括一种被动编队控 制策略，该控制策略具有实现简单、稳定区域大的特点，具有很好的工程应用前景. 最后基 于非线性方程对每种编队策略进行了数值仿真验证，数值结果表明该控制方法能实现编 队.     

利用太阳光压力进行Halo轨道编队控制

利用太阳光压力可以实现地日限制性三体问题中L2点附近编队控制.该编队需要的控制力量级小,常规的推进方式难以实现.太阳帆能产生微小的连续光压力,可以用于Halo轨道附近的编队控制.由于太阳光压力的方向受到限制,只有部分编队构型可以利用太阳光压力实现.该文主要讨论了两种常见的编队构型--直线编队和圆编队,给出了太阳帆能实现的编队构型需要满足的条件.最后,对每种构型的编队进行了数值仿真,仿真结果表明太阳帆能有效的进行编队控制.     

Lunar landing trajectory design based on invariant manifold

The low-energy lunar landing trajectory design using the invariant manifolds of restricted three-body problem is studied.Considering angle between the ecliptic plane and lunar orbit plate the four-body problem of sun-earth-moon-spacecraft is divided into two three-body problems,the sun-earth-spacecraft in the ecliptic plane and the earth- moon-spacecraft in the lunar orbit plane.Using the orbit maneuver at the place where the two planes and the invariant manifolds intersect,a general method to design low energy lunar landing trajectory is given.It is found that this method can save the energy about 20% compared to the traditional Hohmann transfer trajectory,The mechanism that the method can save energy is investigated in the point of view of energy and the expression of the amount of energy saved is given.In addition,some rules of selecting parameters with respect to orbit design are provided.The method of energy analysis in the paper can be extended to energy analysis in deep space orbit design.     

Solar radiation pressure used for formation flying control around the Sun-Earth libration point

Solar radiation pressure is used to control the formation flying around the L2 libration point in the Sun-Earth system. Formation flying control around a halo orbit requires a very small thrust that cannot be satisfied by the latest thrusters. The key contribution of this paper is that the continuous low thrust is produced by solar radiation pressure to achieve the tight formation flying around the libration point. However, only certain families of formation types can be controlled by solar radiation pressure since the direction of solar radiation pressure is restricted to a certain range. Two types of feasible formations using solar radiation pressure control are designed. The conditions of feasible formations are given analytically. Simulations are presented for each case, and the results show that the formations are well controlled by solar radiation pressure.     

行星悬浮轨道附近的编队

研究了不同类型的地球和火星悬浮轨道附近的相对运动．首先,推导了悬浮轨道附近的相对运动方程并将相对运动方程在悬浮轨道附近线性化．利用两种半自然编队控制率进行编队控制,其中一种为被动控制,对工程应用有很大的价值．在两种控制率下,讨论了每种悬浮轨道的稳定区域．由于两种控制率都不能满足特殊的火星悬浮轨道任务要求,于是,根据该任务的要求设计了一种特殊的半自然控制率．该控制率既能满足编队任务的要求也能使相对运动稳定．