Recent years have witnessed the rapid development of satellite internet constellation via low-orbit communication satellites in the main aerospace industries of various countries. For efficient construction of the satellite internet constellation, researchers from the main aerospace industries focus on the technologies of multi-satellite launch of stacked satellite system, as well as autonomous separation and reconfiguration on orbit. Therefore, this paper reviews the application requirements and launch merits of stacked satellites, and introduces the development of the launched stacked satellites all over the world. For the challenges of on orbit separation, this paper also presents the configuration design of the stacked satellites and the optimization design of separation mechanisms. For the separation dynamics of the stacked satellites, the paper outlines the dynamic modeling and simulation methods for the system before separation, the rigid multibody system during separation, and most importantly, the contact detection algorithms during separation. For the ground experiment validations, the paper briefly exhibits the experiment platform and results for separations of two satellites between layers and in the same layer. Finally, the key technologies of stacked satellites separation dynamics are summarized, and several frontier directions for further study are highlighed.

The quantity of space debris on Earth orbit has escalated tremendously in recent years, presenting a significant hazard to human space operations. It is urgent to develop effective measures to capture and remove various space debris. For this purpose, this paper presents a tendon-actuated flexible deployable manipulator. The flexible manipulator consists of several deployable units connected by Cardan joints and actuated by tendons. Compared with the present technologies for capturing space debris such as rigid robotic arm or flying net, this flexible manipulator is deployable, reusable, lightweight and applicable to the capture of large space debris. In order to investigate its deployment dynamics, an accurate dynamic model of the flexible manipulator is established based on the natural coordinate formulation (NCF) and the absolute nodal coordinate formulation (ANCF). Subsequently, numerical simulations are carried out to study the effects of system parameters and the base satellite on its deployment dynamics. Finally, ground experiments for both deployment and bending of the flexible manipulator are conducted to verify its effectiveness and feasibility.