面向木星卫星交会任务的探测器飞行路径规划

针对探测器在木星系统内多次借力的飞行路径和轨道优化设计问题,提出了一种基于三层优化思想的飞行路径规划方法,该方法可根据给定的任务约束和交会目标,自动搜索探测器在木星系统内的借力飞行序列,同时完成标称飞行轨道的优化设计。首先,文章在给定轨道动力学模型和木卫借力模型基础上,建立了面向木卫交会任务的两次借力飞行轨道优化设计模型和求解方法;然后,采用结合遗传算法、全局遍历和贪婪算法的三层优化设计思路,给出了一种环木飞行路径规划方法;最后,以木星四颗卫星的交会任务为例进行了仿真分析。仿真结果表明：针对木卫的交会任务,探测器速度增量需求随木卫借力次数的增多,呈现先显著减小后逐渐增大的现象;探测器采用多次木卫借力的策略,可显著降低探测器的速度增量需求;探测器速度增量达到最优之后,借力目标收敛于交会目标,且速度增量随借力次数的进一步增多而逐渐增大。     

Ground assisted rendezvous with geosynchronous satellites for the disposal of space debris by means of Earth-oriented tethers

Previous studies have shown that extended length Earth-oriented tethers in the geosynchronous (GEO) region can be used to re-orbit satellites to disposal orbits. One such approach involves the extension of a GEO based tether, collection of a debris object, and retraction of the tether, which transfers the retracted configuration to a higher energy orbit for debris disposal. The re-extension of the tether after debris disposal returns the configuration to the near-GEO altitude. The practical feasibility of such a system depends on the ability to collect GEO debris objects, attach them to a deployed tether system, and retract the tethers for transfer to the disposal orbits.This study addresses the collection and delivery of debris objects to the deployed tether system in GEO. The investigation considers the number, type and the characteristics of the debris objects as well as the collection tug that can be ground controlled to detect, rendezvous and dock with the debris objects for their delivery to the tethers system.A total of more than 400 objects are in drift orbits crossing all longitudes either below or above the geostationary radius. More than 130 objects are also known to librate around the stable points in GEO with periods of libration up to five or more years. A characterization of the position and velocity of the debris objects relative to the collection tug is investigated. Typical rendezvous performance requirements for uncooperative GEO satellites are examined, and the similarities with other approaches such as the ESA's CX-OLEV commercial mission proposal to extend the life of geostationary telecommunication satellites are noted.     

近地星座异面遍历交会轨道全局优化

根据J 2摄动对轨道面的长期影响规律,提出了一种在近地低轨道星座卫星之间进行异面轨道交会的解析近似方法,并用于建立多星多约束遍历交会的混合整数规划模型,能够快速获得多星交会次序、交会时刻的最优解。仿真算例表明提出的方法适用于在轨服务、构型重建等类型任务的快速优化,计算速度和燃料消耗优于以往类似算法。     

Orbital rendezvous mission planning using mixed integer nonlinear programming

The rendezvous and docking mission is usually divided into several phases, and the mission planning is performed phase by phase. A new planning method using mixed integer nonlinear programming, which investigates single phase parameters and phase connecting parameters simultaneously, is proposed to improve the rendezvous mission’s overall performance. The design variables are composed of integers and continuous-valued numbers. The integer part consists of the parameters for station-keeping and sensor-switching, the number of maneuvers in each rendezvous phase and the number of repeating periods to start the rendezvous mission. The continuous part consists of the orbital transfer time and the station-keeping duration. The objective function is a combination of the propellant consumed, the sun angle which represents the power available, and the terminal precision of each rendezvous phase. The operational requirements for the spacecraft–ground communication, sun illumination and the sensor transition are considered. The simple genetic algorithm, which is a combination of the integer-coded and real-coded genetic algorithm, is chosen to obtain the optimal solution. A practical rendezvous mission planning problem is solved by the proposed method. The results show that the method proposed can solve the integral rendezvous mission planning problem effectively, and the solution obtained can satisfy the operational constraints and has a good overall performance.     

Fast solar sail rendezvous mission to near Earth asteroids

The concept of fast solar sail rendezvous missions to near Earth asteroids is presented by considering the hyperbolic launch excess velocity as a design parameter. After introducing an initial constraint on the hyperbolic excess velocity, a time optimal control framework is derived and solved by using an indirect method. The coplanar circular orbit rendezvous scenario is investigated first to evaluate the variational trend of the transfer time with respect to different hyperbolic excess velocities and solar sail characteristic accelerations. The influence of the asteroid orbital inclination and eccentricity on the transfer time is studied in a parametric way. The optimal direction and magnitude of the hyperbolic excess velocity are identified via numerical simulations. The found results for coplanar circular scenarios are compared in terms of fuel consumption to the corresponding bi-impulsive transfer of the same flight time, but without using a solar sail. The fuel consumption tradeoff between the required hyperbolic excess velocity and the achievable flight time is discussed. The required total launch mass for a particular solar sail is derived in analytical form. A practical mission application is proposed to rendezvous with the asteroid 99942 Apophis by using a solar sail in combination with the provided hyperbolic excess velocity.     

面向GEO目标的快速在线在轨服务任务规划

针对地球同步轨道多对多在轨服务任务规划问题,提出了一种基于拍卖算法和先验知识的改进启发式拍卖算法(IHAA)。首先,建立了基于Lambert变轨的任务规划问题表征,设计了给定变轨时长约束下的快速燃料最优估计策略。其次,针对考虑J 2摄动影响的航天器在轨服务规划问题,提出了一种基于拍卖算法的快速求解流程。其中,为确定每一轮拍卖算法任务列表,提出了基于变轨先验知识的目标优先级排序启发式策略,实现了快速的服务时序确定方法;此外,为减少因部分航天器服务能力低导致的分配失败情况,设计了一种基于失败任务再分配的重拍机制。最后,将所提算法与遗传算法、模拟退火算法进行了对比,结果表明IHAA可以快速给出相对适应度较高的规划结果,可用于突发事件星上在线自主规划,亦可提供优化算法初值以提升规划效率。     

基于脉冲初值的小推力转移轨道优化研究

针对小推力转移轨道优化过程往往忽略初值多样性的现状,研究了基于不同脉冲初值的小推力转移轨道优化问题。基于直接法的离散思想建立了小推力转移轨道优化模型,提出了基于粒子群和序列二次规划的组合优化算法,以地球1∶1共振近地小行星2016HO3交会任务为例,将3种典型的脉冲轨道作为初值设计了燃料最优小推力转移轨道。仿真结果表明:3种初值轨道优化得到了2个小推力转移发射窗口,两者燃料消耗差距不超过6%。不同的初值对小推力轨道的整体性能指标影响较小,但开关机时刻和推力方向的变化会产生较大差异,从而得到不同的最优控制曲线。     

伴随卫星的燃料-时间优化回收

伴随卫星回收是伴星应用中的一项主要技术。航天任务需求对伴星回收问题不仅提出了最省燃料要求，而且提出了最小时间要求。本文设计了一条稳定的燃料-时间优化回收轨道。从相对运动的Hill方程出发，给出伴星回收问题描述，阐述回收轨道设计思想及稳定回收条件，提出一种有效的螺旋式回收策略，探讨参数确定方法，并对回收轨道的特点和稳定性进行分析，最后研究了燃料消耗量与回收时间及初始相位的关系。仿真结果表明，利用螺旋回收策略，可以保证伴随卫星快速、稳定回收，且能在燃料消耗量与回收时间之间寻求最佳折衷。     

绳系卫星系统交会对接的应用与设计

文章介绍了绳系系统交会对接这项新技术在空间中的应用。主要包括:空间站利用系绳与航天器交会对接,实现为空间站提供各种供给;利用绳系系统与空间碎片对接,可回收或转移空间碎片,保护空间环境;利用一级或多级的绳系系统组成轨道转移系统,实现向地球同步轨道或火星轨道上转移和运送有效载荷。文章还介绍了绳系交会对接系统的设计,包括系统的一般控制方法和算法以及系统的结构设计。随着各项相关技术的发展,绳系卫星系统交会对接将发挥更大作用。     

Opportunity options for rendezvous,flyby and sample return mission to different spectral-type asteroids for the 2015–2025

The feasible rendezvous, flyby and sample return mission scenario to different spectral-type asteroids for the 2015–2025 are investigated. The emphasis is put on the potential target selection and the design of preliminary interplanetary transfer trajectory in this paper. First, according to different scientific motivations, some potential targets with different spectral-type and physical property are selected. Then, some optimal rendezvous and sample return opportunities for different spectral-type asteroids are presented by using pork-chop plots method and Sequential Quadratic-Programming (SQP) algorithm. In order to reduce the launch energy and total velocity increments for sample return mission, the Earth swingby strategy is used. In addition, the feasible trajectory profiles of flyby and rendezvous with two different spectral-type asteroids in one mission are discussed. A hybrid optimization method combing the Differential Evolution (DE) algorithm and SQP algorithm is introduced as a trajectory design method for the mission. Finally, some important parameters of transfer trajectory are analyzed, which would have a direct impact on the design of spacecraft subsystem, such as communication, power and thermal control subsystem.     

大范围轨道机动的燃料消耗优化方法

针对航天器大范围轨道交会提出了二冲量燃料最省机动方案的数值寻优算法及多冲量机动方案的啸声境遗传算法.利用共面圆\椭圆轨道间的转移实例对两种算法正确小生境遗传算法.利用共面圆\椭圆轨道间的转移实例对两种算法正确性进行了验证,通过仿真实验,比较了大范围交会轨道机动中不同冲量次数对总燃料消耗的影响,分析得出了非共面轨道交会机动时燃料最省的指导性方案.     

多脉冲C-W交会的优化方法

在航天器的近距离交会中,常采用C-W交会的方法.本文发展了多脉冲C-W交会.建立了一般情况下的优化模型,并进行了分析.为了减少优化变量,提出了三种速度脉冲施加模式：切向、径向、变径向.提出了一种简单的误差修正方法：通过修正计算的目标位置而减小仿真误差.在实际算例中采用了遗传算法.针对多个初始状态,不同的脉冲次数进行了仿真计算,并与文献中的算法进行了对比,精度有了进一步的提高,结果证明优化模型是可行的,可以应用于多种情况.     

Simulation model for the operation of space freighters

This paper makes the attempt to illustrate the need for a detailed operational analysis of future space transportation systems with the help of computer-based simulation models. The basic approach deemed suitable for such a systems simulation is explained in some detail. A reference program (100,000 Mg payload per year during 25 years) for a reference mission (heavy cargo transport to GEO for SPS construction) has been selected. A base-line launch vehicle (fully reusable ballistic all chemical three stage vehicle) has been defined, which is considered a serious applicant for such a mission. It was found that the take-off mass of this type of vehicle should be as large as practical from the viewpoint of cost-effectiveness. The example chosen has a GLOW of 10,000 Mg and lifts more than 100 Mg to GEO.With consideration of the operational parameters the simulation model evaluates the annual production rates, inventory of stages, utilization of facilities and operational cost, which amount within this frame of reference to about 96 $/kg net payload delivered to GEO in terms of 1980 dollars and contribute the main share to the total transportation cost.     

基于改进伪谱反馈控制的远程变轨闭环制导

利用最优反馈控制和轨迹快速重构技术,设计一种有限推力空间远程变轨自适应闭环制导方法。首先给出了最优反馈控制的求解原理和必要条件。将空间变轨动力学模型特点和伪谱法相结合,设计基于状态量缩减的计算效率改进策略以提高轨迹优化的实时性。基于改进伪谱法进行逐次轨迹快速重构,利用开环最优解形成闭环反馈,从而保证制导指令的实时更新,并通过引入控制逻辑改进制导算法。远程交会仿真表明,该闭环制导方法在保证任务指标具有一定最优性的同时,可以有效抑制多种参数不确定性和外界干扰的影响,具有较高的制导精度、自适应性和鲁棒性。     

有限推力航天器双主动交会的最优控制

研究了两异面椭圆轨道的有限推力航天器在协同轨道机动以完成交会任务(双主动交会)时的最优控制问题.构造了有限推力航天器双主动交会的数学模型,讨论了其实现最优控制的必要条件.针对推进剂总消耗最少和有限推进剂约束下的最短时间交会2种不同情况,采用直接配置法和序列二次规划法求解了反平方力场中的最优控制数值解.考察了不同初始参数对双主动交会最优控制历程的影响,并将双主动交会形式与主被动交会形式进行了对比.结果表明,当两航天器质量接近时,双主动交会在减少燃料消耗或缩短交会所需时间方面具有明显优势.     

一种用于远程交会的末段制导优化方法

研究了E制导方法实现空间飞行器远程交会末制导的问题.在能量最省指标约束下,采用函数极值方法求解出最优交会时间.针对E制导方法对发动机推力可变的要求,采用PWPF调节器对具有常推力轨道发动机的空间飞行器推力加速度进行调制,得到E制导方法要求的"变推力".仿真结果表明该方法可以实现远程交会末制导且精度较高.     

多约束交会对接发射窗口的分析和规划

针对交会对接任务对发射窗口的轨道日照角、光学导航测量设备阳光抑制角和轨道共面等多项约束,建立了交会对接发射窗口计算数学模型,给出了交会对接发射窗口计算方法与流程,分析了各种约束对交会对接发射窗口的影响。计算并构建了交会对接任务目标飞行器和追踪飞行器的年度日照发射窗口集合。按照2种任务规划思路分别给出了确定目标飞行器和追踪飞行器年度共面窗口集合的方法,为多约束交会对接年度发射窗口的日窗口和时刻窗口的分析和规划提供了清晰的结果。仿真结果验证了交会对接年度发射窗口集合的正确性和有效性,模型、方法和结果可作为交会对接任务发射窗口分析和规划的依据。
     

考虑轨道摄动影响的多冲量交会规划方法研究

当交会时间较长时需要在轨道规划中考虑摄动的影响,本文基于虚拟瞄准点的思想,研究了考虑轨道摄动情况下的固定时间拦截问题求解方法,并提出了考虑轨道摄动影响的多冲量交会规划方法.通过仿真算例验证了算法的有效性,并对基于二体模型和考虑摄动的规划结果进行了对比.     

天基空间监视交会计算和可观测时段预报的误差分析

将卫星和目标的轨道预报误差引入天基空间目标监视的任务规划中,研究了交会计算和可观测时段预报的误差分析方法。在协方差转换基本方法和交会信息计算公式的基础上,推导了从RSW轨道坐标系到RAE参数（距离、方位角、俯仰角）的协方差转换方法。对LEO和GEO目标观测分别引入相对速度和角距变化率,给出了可观测时段误差的分析方法。算例表明本文的计算结果与Monte-Carlo仿真结果相对误差不大于4%,典型轨道误差下LEO和GEO目标的可观测时段误差分别为0.2秒和3秒量级。该方法对任务规划和姿态及相机导引具有指导意义,还可用于分析成功观测对轨道预报精度的需求。