Dynamic behavior of a tethered system with multiple subsatellites in elliptic orbits

Dynamic behavior of a tethered system with multiple subsatellites subjected to both atmospheric drag and changes of gravity gradient in elliptic orbits is investigated. The tethered system is modeled as a combination of rigid-body subsatellites and lumped tether masses, and flexibility of the tether is considered. The results of the numerical experiments show that the libration of the total system can diverge due to the atmospheric drag, and the total system begins tumbling motion later. The physical interpretation is clearly presented by focusing on the deviation from the periodic motion. Effects of the atmospheric drag on the attitude motions of the subsatellites and the tension states of the tether are also investigated. It is shown that the large perturbations can cause partial slack states of the tether, which causes unstable attitude motions of some of the subsatellites.