ESO-based saturated deployment control of tethered satellite system with finite-time tracking performance guarantees⁎This work was supported in part of the Major Program of National Natural Science Foundation of China (Grant No. 61690211), Open Fund of National Key Laboratory of Aerospace Flight Dynamics (Grant No. 6142210200303), Open Fund of Key Laboratory of Space Intelligent Control Technology, and Natural Science Foundation of Hunan Province. Issue 2 (2020)