Modeling and stability analysis of a tethered asteroid probe system based on multi flexible body dynamics

The tethered asteroid probe system refers to a method of connecting a probe to an asteroid using a tether. This system allows the probe to hover near the asteroid's surface without consuming fuel, making it valuable for conducting high-precision exploration, sampling, and other exploration tasks. However, various physical characteristics, such as the tether length, flexibility, gravity, internal tension, and the initial velocity state of the probe, affect the probe's hovering position and stability. In this article, the dynamic model and stability of tether probes near irregular asteroids are investigated. By considering the mass and elasticity of the tether, a multi-flexible body dynamic equation is established to describe the behavior of the probe and tether under the influence of the gravitational field of the asteroid. Dynamic equations can describe the dynamical response of the probe when switching between the tensed and relaxed states. Moreover, the changes in the position and stability of the stable range caused by the tether are analyzed. The findings suggest that connecting the probe to the asteroid through tethers significantly expands the stable operation range of the probe. The length of the tether and the amplitude of the tension significantly impact the dynamic characteristics of the probe and the stable range. Additionally, compared with the assumption that the tether is assumed to be massless and rigid, the initial range in which the tethered system can be stable is significantly reduced. Hence, the influence of the tether mass, elasticity, and damping should not be overlooked. The research presented in this article holds great significance for asteroid proximity exploration and sampling tasks that utilize tether systems. By understanding the dynamics and stability of tethered probes near irregular asteroids, human capabilities in exploring and studying these celestial bodies can be enhanced.