Dynamic behaviour of a tethered system with multi-sub-satellites in elliptic orbits

Dynamic behaviors of a tethered system in elliptic orbits are investigated. The tethered system is modeled as a combination of rigid body satellites and lumped tether masses, and the effects of tether elasticity and atmospheric drag are included. The libration of the tethered system and the attitude motion of the sub-satellite are focused especially, and their fundamental characteristics are clarified through various numerical simulations. It is shown that the amplitude of libration of the total system diverges due to the effect of atmospheric drag. And the larger eccentricity, and the lower height of perigee enhance the instability of libration. The lateral vibration of the tether also arises duc to atmospheric drag, and it excites the amplitude of attitude motion of sub-satellites. In the case of multi-sub-satellites, the lateral vibration diminishes because of the presence of middle-attached satellites. and consequently amptitude of attitude motion of sub-satellites also diminish.