纳秒多脉冲激光驱动近地轨道小尺度空间碎片的动力学机制研究

The purpose of this project is to investigate the dynamic mechanisms including impulse transmission efficiency, kinetic response behavior and active orbit maneuver performance of multi-pulse nanosecond laser driving small-sized space debris in low earth orbit (LEO), and it has very important theoretical significance and practical value for ensuring the safe operation of spacecraft in orbit greatly. In the project, aluminum alloy debris materials of 10cm level in LEO is used as research targets, an impulse coupling model of multi-pulse nanosecond laser driving the aluminum target will be effectively established in atmospheric or vacuum environment. The change laws of the recoil impulse and the transforming rules between the macroscopic mechanics effect and the transient flow field of plasma plume will be mastered, and the optimized laser parameters and impulse coupling coefficients are subsequently to be discussed (the optimized parameters). On this basis, a dynamic response model of multi-pulse nanosecond laser driving the aluminum target will be obtained by combining nonlinear finite element method (FEM) and boundary element method (BEM), and the influence rules of optimized laser parameters and impulse coupling coefficients on the dynamic response behavior of driving different debris will be investigated based on different laser irradiations. As a result, the active orbit maneuver model of multi-pulse nanosecond laser driving the aluminum target will be proposed based on ground-based or space-based platform, and the evolution laws of active deorbit of optimized laser parameters and impulse coupling coefficients driving different debris in coplanar/non-coplanar conditions will be achieved based on different laser irradiations. By breaking through some of key problems in the research contents, such as the establishment of the dynamic response model and the active orbit maneuver mode of multi-pulse nanosecond laser driving the aluminum target, the prospective achievements of the project can provide a necessary theoretical foundation and key technical support for the application of multi-pulse nanosecond laser active removing small-sized space debris in LEO.

本项目围绕纳秒多脉冲激光驱动近地轨道(LEO)小尺度空间碎片的冲量传递效能、动态响应行为以及主动变轨特性等动力学机制问题展开研究，对于最大限度地保证在轨航天器的安全运行具有重要的理论意义和实用价值。以10cm量级LEO铝合金碎片为对象，基于大气/真空环境建立纳秒脉冲激光驱动下的冲量耦合模型，掌握宏观力学效应与等离子体羽流瞬态流场之间的转化及反喷冲量形成规律，探究最优激光参数和冲量耦合系数(最优参量)；基于非线性有限元/边界元构建纳秒脉冲激光驱动下的动态响应模型，获得不同辐照方式下最优参量驱动不同碎片动态响应的影响规律；基于地基/天基平台建立纳秒脉冲激光驱动下的主动变轨模型，寻求不同辐照方式的最优参量驱动不同碎片在共面/异面下的降轨演化规律。通过突破纳秒脉冲激光驱动下的动态响应模型与主动变轨模型建立等问题，预期成果为纳秒脉冲激光清除LEO小尺度碎片技术的应用提供必要的理论基础和关键技术支持。

近地轨道空间碎片数量的不断增长使得近地空间环境日益恶化，尤其是对于近地轨道区域具有较大动能的10cm左右量级的厘米级小尺度空间碎片，目前既难以跟踪编目和监测预警又难以有效防护，被国际社会公认为是对航天器威胁最大的碎片，现有的碎片减缓与防护方法已不能有效限制这类危险碎片数量的继续增长。由于大部分航天器工作在近地轨道，为了最大限度地保障近地空间环境安全，主动移除该区域的小尺度空间碎片势在必行。高能脉冲激光辐照技术目前被认为是最具备应用潜力的主动移除方法，该技术主要是通过高能脉冲激光辐照产生等离子体形成的冲量耦合效应驱动碎片主动变轨来实现。本项目以10cm量级的铝靶空间碎片为研究对象，围绕纳秒多脉冲激光驱动近地轨道小尺度空间碎片的冲量传递效能、动态响应行为以及主动变轨特性等动力学机制问题展开了深入研究。项目的开展对于最大限度地保证在轨航天器的安全运行具有重要的理论意义和实用价值，同时也为促进纳秒脉冲激光主动移除近地轨道小尺度空间碎片技术的进一步发展提供了重要的理论和技术支持。取得的研究成果包括：给出了大气/真空环境下包含不同物理机制的纳秒脉冲激光驱动小尺度空间碎片的冲量耦合模型，掌握了宏观力学效应与等离子体羽流瞬态流场之间的转化与反喷冲量的形成规律；提出了基于非线性有限元的纳秒脉冲激光驱动小尺度空间碎片的动态响应模型，获得了不同辐照方式下最优激光参数与冲量耦合系数驱动不同特性碎片动态响应行为的影响规律；构建了基于地基/天基平台的纳秒脉冲激光驱动小尺度空间碎片的主动变轨模型，揭示了不同辐照方式的最优激光参数与冲量耦合系数驱动不同特性碎片在共面/异面条件下主动降轨的演化规律。本课题成果不仅为纳秒脉冲激光驱动近地轨道小尺度空间碎片的系统研究提供了有价值的指导和重要参考，而且也为纳秒脉冲激光驱动近地轨道小尺度空间碎片主动变轨的方案设计及效果评估提供了可靠地理论依据和高效地基础仿真平台。