Scientists describe deployment of three-body chain-type tethered satellites in low-eccentricity orbits

Successful deployment is critical for TSAR tethered systems.

Several control methods, including length, length rate, tension, and thrust-aided control, have been proposed over the years. Among them, adjusting tension is a viable yet challenging approach due to the 's strong nonlinearity and underactuated traits.

Current tether deployment schemes focus on two-body TSS, with little emphasis on multi-TSSs. In a research article recently published in Space: Science & Technology, a research team led by Zhongjie Meng from Northwestern Polytechnical University has developed a new deployment strategy for a 3-body chain-type tethered satellite system in a low-eccentric elliptical orbit.

First, authors establish the motion model of a 3-body chain-type TSS in a low-eccentric elliptical orbit. Two assumptions are made: (a) the tethers are massless; (b) only the planar motion is considered. The proposed model consists of 3 point masses (m1, m2, and m3) and 2 massless tethers (L1 and L2).

The orbit of m1 is defined by its orbital geocentric distance r and true anomaly α; the position of m2 relative to m1 is determined by tether L1 and in-plane libration angle θ1; the position of m3 relative to m2 is determined by L2 and θ2.

Model of 3-body chain-type tethered satellite system. Credit: Space: Science & Technology

Schematic of the deployment control framework. Credit: Space: Science & Technology

Error and tension integral in Schemes 2 and 3. Credit: Space: Science & Technology