The space harpoon is a rigid-flexible, coupled debris capture method with a simple, reliable structure and a high adaptability to the target. For the process of impacting and embedding the harpoon into the target plate, the effect of friction at a low-velocity impact is studied, and the criteria for effective embedding of the harpoon and the corresponding launch velocity are determined. A simulation model of the dynamics of the harpoon and the target plate considering tangential friction is established, and the reliability of the numerical simulation model is verified by comparing the impact test, focusing on the kinetic energy change and embedding length during the impact of the harpoon. The results show that the frictional effect in the low-velocity impact is more obvious for the kinetic energy consumption of the harpoon itself, and the effective embedding of the harpoon into the anchored target ranges from 50~90 mm, corresponding to a theoretical launch initial velocity between 88.4~92.5 m/s.

Tether-net is a promising active debris removal technique, and a closing mechanism can ensure the reliable wrapping of space debris by using tether-net. This study focuses on the dynamics model of the split closing mechanism and the sliding joint between thread and ring. First, a new kind of closing mechanism is proposed, which drives the closing thread to close the net mouth through the split masses, and the mass-spring-damper method is used to model tether-net. Thereafter, for the first time, the model of thread-ring sliding joint is proposed based on the mass-spring-damper method, which can be used to simulate the closing process of tether-net. Finally, one-edge closure experiment of the net is carried out and the experimental results are compared with the simulation results, and the closing process of the tether-net is simulated by using the thread-ring sliding joint. Results reveal that the thread-ring sliding joint can be used to simulate the relative slip between the thread and the ring, and the tether-net can wrap the target reliably in a short time by using the split closing system. The split closing mechanism can make it possible for the tether-net to close successfully, whether it starts to work before or after the net contacts with the target.

Power-form nonlinear contact force models are widely adopted in relatively moving parts of macro (e.g., rolling bearings considering Hertzian contact restoring force between rolling elements and bearing raceways) or micro (e.g., the micro cantilever probe system of atomic force microscopy) scale mechanical systems, and contact resonance could cause serious problems of wear, contact fatigue, vibration, and noise, which has attracted widespread attention. In the present paper, the softening/hardening stiffness characteristics of continuous and one-sided contact power-form nonlinear spring models are addressed, respectively, by the analysis of the monotone features of resonant frequency-response skeleton lines. Herein, the period-n solution branch and its stability characteristics are obtained by the harmonic balance and alternating frequency/time domain (HB–AFT) method and Floquet theory. Compared with previous studies, this paper will furtherly clarify the influences of externally normal load, the power form exponent term, and excitation amplitude on the softening/hardening stiffness characteristics of general power-form spring systems. In addition, for a power-form system with a one-sided contact, the phenomena of primary and super/sub-harmonic hysteretic resonances inducing period-doubling, folding bifurcation, the coexistence of multiple solutions are demonstrated. Besides, it gives the evolution mechanism of two types of intermittency chaos in a one-sided contact system. The overall results may have certain basic theoretical significance and engineering values for the control of vibration and noise in contact mechanical systems.