小天体动能撞击防御中动量传递因子敏感参数分析

动量传递因子β是评估动能撞击效果的重要参量。根据动能撞击过程中动量传递因子的理论模型，分析了撞击器特性参数和小天体结构特性参数对动量传递因子取值的影响，并对不同动能撞击方案以及不同材料特性小天体的成坑效应和动量传递因子进行分析。研究表明：标度律参数μ对β影响较大，μ是地面实验拟合得到的系数，与材料强度特性相关；当小天体为单体岩石结构时，撞击器速度及密度、小天体密度及表面强度对β影响较大，而撞击器半径和小天体引力对β影响较小；当小天体为碎石堆结构时，β对撞击器特性参数和小天体特性参数不敏感，且数值较小。对三种不同动能撞击方案的成坑效应与动量传递因子形成规律进行研究，发现撞击器初始动能对β影响较大。当小天体为单体岩石结构时，其对应的动量传递因子取值较大，而当小天体为碎石堆结构时，其对应的β取值较小且基本不变。对相同动能撞击方案下不同材料特性小天体（C型、S型和X型小行星）产生的撞击效应进行分析，发现在引力主导时，βC>βS>βX，而在强度主导时β取值较小且基本相同。

Analysis of Sensitive Parameters of Momentum Transfer Factor in Kinetic Impact Defending Small Bodies

Momentum transfer factor β is the key factor to evaluate effect of kinetic impact. In this paper, theoretical model of momentum transfer factor in kinetic impact is investigated, as well as the influence of impactor properties and small body structure properties on the factor. Meanwhile, the crater effect and momentum transfer factor of small bodies with different kinetic impact schemes and structural characteristics are studied. Results show that scaling law parameter μ, a coefficient related to strength properties of target material which is obtained by ground experiment fitting, has a great effect on the factor. The velocity/density of impactor and density/surface strength of small body have a great effect on the factor for small body with a single rock structure, while radius of impactor and gravity of small body have a small effect. In the meantime, the value of β is significant. The factor is insensitive to parameters of impactor properties and small body structure properties for small body with a rubble-pile structure, and its value is close to 1. The formation of crater and momentum transfer factor in three different kinetic impact schemes indicates that the initial kinetic energy of impactor has a great influence on the factor. In the same kinetic impact scheme where gravity dominates the crater formation, the momentum transfer factor of a C-complex asteroid is largest followed by S-complex and X-complex. However, when strength dominates crater formation, the factors of all complexes are smaller and basically the same.