随着人类空间活动的日益频繁，地球轨道的人造空间目标数量迅速增加，70%的空间目标都集中于500 ~ 1000 km的低轨道空间，且碰撞级联效应将是进一步增加低轨空间目标的最主要原因。低轨高密度的空间目标很大程度上对在轨有效卫星、人类空间活动等构成威胁，如果仅靠任务后处理等减缓新空间目标产生的应对措施，很难遏制空间目标数量稳步不可控的增长趋势。因此，主动空间目标清除离轨才是解决现有问题的最有效措施。

       相较于轨道唯一、分布集中的地球中高轨道和同步轨道，低轨道的空间目标数量多、轨道高度和倾角分散，使得目标主动清除显得较为困难，现有提出的或较为成熟的主动捕获及主动目标离轨技术不能有效适用于所有低轨道区域，且在轨主动清除离轨过程需要消耗大量燃料工质，现有方法/技术不能有效兼顾技术可行性和经济性。面向低轨空间目标的无工质消耗推进/离轨，以空间电动绳系（安培力作用机理）、静电推进（洛伦兹力作用机理）、阻力帆、地基激光推移等为代表的主动清除方法得到了发展，方法理论可行但都存在各自的技术限制。

       本文针对低轨目标主动离轨，基于地磁场的磁力矩效应，提出了一种无工质消耗的地磁储能投送离轨新方法，方法具备作用机理明晰、控制策略与使用灵活、投送离轨能力对尺度依赖性小等特点。本文针对该方法主要在以下方面完成了相关研究。

       完成了低轨目标地磁储能离轨机理研究。首先，指出了储能的能量（角动量）来源为对地磁场作用下的旋动（磁力矩）效应的持续累积，明晰了目标储能投送离轨原理，为储能机理建立及定向储能策略构建奠定基础。其次，对比了现有通用的高精度国际地磁参考场（IGRF）模型及简化近似磁偶极子（dipole）模型的计算精度，以dipole模型为基础，研究了地磁场的磁力和磁力矩效应，建立了地磁定向储能机理，并构建了两种在轨飞行定向储能策略：轨道坐标系Y_o轴或Z_o轴定向储能。进行了IGRF和dipole二种地磁场模型下的磁力矩及磁力矩累积仿真实验，验证了在轨定向储能机理。最后，考虑地球扁率引起的摄动力、大气阻力摄动等外力，建立了相应的目标投送离轨轨道动力学方程。

       完成了地磁储能投送能力及适用范围研究。首先，基于简化的dipole地磁场模型，研究了两种定向储能策略的储能能力，给出了对应的单轨道周期储能计算式，大量储能仿真算例验证了地磁储能能力，并指出了其适用范围。其次，对比了地磁储能方法与现有典型空间储能设备的储能能力，发现地磁储能具有很强的优势。最后，建立了投送航天器-低轨目标离轨组合系统的简化刚性系统，给出了两种定向储能策略下的离轨能力计算式，大量仿真算例验证了投送离轨能力，比现有典型离轨方法具有明显的优势。

       设计研制了地磁储能地面原理性实验装置。首先，多方面分析了低轨飞行储能环境特点，对应等价分析了地面实验设计，分解了装置总体需求指标，提出了装置原理，设计了总体构架和总体方案。其次，重点设计了关键部件-磁线圈系统（包括加速投送机构），研制了地磁储能地面原理实验装置。最后，考虑磁力矩、气动阻力矩、干扰力矩等，基于系统动量矩定理，完成了地面装置系统建模，进行了相应的仿真控制。

       设计并完成了地面原理性验证实验。分析了地面原理性实验目的，设计了验证实验流程，进行了两大类实验：测试与标定实验、储能原理性实验，重点标定了装置系统干扰力矩，大量多工况储能原理性实验验证了地磁储能原理可行性、地磁储能能力，实现了地磁场能的获取、转换和储存，基本验证了低轨地磁场效应的空间利用。

       完成了在轨储能优化与控制方法研究。首先，针对两种定向储能策略，以无附加磁力矩累积为单轨道周期的储能优化目标，分别构建了较优的分段规划地磁储能控制策略，并仿真验证了策略的可行性。其次，设计了两种在轨地磁储能目标投送系统：单投送杆式和双投送杆对转式，并给出了对应的储能控制方法。最后，针对在轨储能启动加速旋动和减速消旋过程中存在的章动问题，设想了两种航天器结构，并探讨了相应的章动抑制控制方法。

       With the increasing frequency of human space activities, the number of man-made space objects in earth orbit increases rapidly. 70% of the space objects are concentrated in the 500-1000 km low Earth orbit (LEO), and the Kessler Syndrome (collisional cascading or ablation cascade effect) will be the main reason for the further increase of LEO space objects. The high-density space objects pose a threat to the functional satellites in orbit and human space activities to a large extent. It is difficult to curb the steady and uncontrollable growth trend of the number of space objects, if we only rely on the post mission disposal (PMD) measures to mitigate the generation of new space objects. Therefore, the most effective measure to solve the existing problems is the active space objects removal.

       Compared with the space objects in medium Earth orbit (MEO), high Earth orbit (HEO) and geosynchronous orbit (GEO), the number of space objects in LEO is large, and the orbital height and inclination are scattered, which makes the active object removal much more difficult. The existing or mature active space object capturing and active object deorbiting technology cannot be effectively applied to all LEO regions, and the space operation for the active object capturing and deorbiting consumes a lot of energy (propellant working mass). So the existing capturing and deorbiting methods / technologies cannot effectively balance the feasibility and economy of the object removal. For the LEO space object propulsion or deorbiting without working mass consumption, the active removal methods such as space electrodynamic tether (EDT, its mechanism is Ampere force), electrostatic propulsion (its mechanism is Lorentz force), drag sail and ground-based laser propulsion have been developed. The theory of these methods is feasible, but they all have their own technical limitations.

       In this paper, a new geomagnetic energy approach to LEO space object deorbiting without the working mass consumption is proposed based on the magnetic torque effect of a magnet in the geomagnetic field. The method is characterized by the clear mechanism, flexible control strategy and application, and low dependence on the scale. In this paper, the research on this method is mainly completed in the following aspects.

       The mechanism of LEO geomagnetic energy storage and space object deorbiting is studied. Firstly, it is pointed out that the energy (angular momentum) source of the energy storage is the continuous accumulation of the rotation (magnetic torque) effect under the geomagnetic field, and the principle of LEO object deorbiting on the basis of the energy accumulation is clarified, which lays the foundation for the establishment of the energy storage mechanism and the construction of the directional energy storage strategy. Secondly, the calculation accuracy of the existing high-precision international geomagnetic reference field (IGRF) model and the simplified approximate magnetic dipole (dipole) model are compared. Based on the dipole model, the magnetic force and magnetic torque effects of the geomagnetic field are studied, and the mechanism of geomagnetic directional energy storage is built. Two kinds of on orbit flight directional energy storage strategies are constructed: directional energy storage in Y_o axis or Z_o axis of the orbital coordinate system. The simulation experiments of magnetic torque and magnetic torque accumulation under IGRF and dipole geomagnetic field models are carried out, and the mechanism of on orbit directional energy storage is verified. Finally, considering the external forces such as the perturbation force caused by the earth oblateness and the atmospheric drag perturbation, the corresponding dynamic equation of the LEO object deorbiting is established.

       The research on the capability of geomagnetic energy storage and its application scope has been completed. Firstly, based on the simplified dipole geomagnetic field model, the energy storage capacity of two kinds of directional energy storage strategies is studied, and the corresponding formula for the single orbit periodic energy storage is given. A large number of energy storage simulation examples verify the geomagnetic energy storage capacity, and point out its application scope. Secondly, compared with the existing typical space energy storage equipment, and it is found that the energy storage capacity of the proposed method has a strong advantage. Finally, the simplified rigid system of the combined object of spacecraft and LEO object is established, and the calculation formulas of the deorbiting capability under two kinds of directional energy storage strategies are given. A large number of simulation examples verify the deorbiting capability, which has obvious advantages over the existing typical methods.

       The ground-based experimental systems for the proof-of-principle experiments of the geomagnetic energy effect is designed and developed. Firstly, the characteristics of LEO flight energy storage environment are analyzed in many aspects, and then the ground experiment design is analyzed, and the overall specifications of the systems are decomposed. The energy storage principle of the ground-based systems is proposed, and the overall framework and scheme are designed. Secondly, the key magnetic coil subsystem (including accelerating delivery mechanism) is designed, and the ground-based experimental systems for the principle verification is developed. Finally, considering the magnetic torque, aerodynamic resistance torque and disturbance torque, the ground-based system modeling is completed based on the system momentum theorem, and the corresponding simulation control is carried out.

       The proof-of-principle ground-based experiments is designed and completed. This paper analyzes the purpose of proof-of-principle experiments, designs the experimental procedure, and carries out two kinds of experiments: the testing and calibration experiment and the geomagnetic energy effect verification experiment. Experiments focusing on the disturbance torque calibration of the ground-based systems are carried out. A large number of principle verification experiments under multiple conditions verify the feasibility of the principle of geomagnetic energy storage and the storage ability of geomagnetic energy effect. The LEO geomagnetic energy harvesting, exchange and storage are experimentally achieved, and LEO geomagnetic energy utilization in space is elementarily verified.

        The optimization and control method of on orbit energy storage is completed. Firstly, taking no additional magnetic torque accumulation as the energy storage optimization objective of single orbit period, the optimal piecewise planning control strategies of geomagnetic energy storage are constructed respectively for the two kinds of directional energy storage strategies. The feasibility of the planning strategy is verified by simulations. Secondly, two kinds of systems for the on-orbit geomagnetic energy storage and object delivery are designed: single delivery rod type and double delivery rod counter rotating type, and the corresponding energy storage control methods are given. Finally, aiming at the nutation problem in the process of accelerating spinning and decelerating spinning, two kinds of spacecraft structures are proposed, and the corresponding nutation suppression control methods are discussed.