Ultrahigh precision ultrahigh stability ultra-agile multi-stage satellites are implemented by introducing a two-stage control ultra-Agile ultra-Stable and ultra-Pointing platform （ASP） to the spacecraft platform. The ASP isolates the vibration and enables rapid maneuver ability of payloads. Additional connection may degrade the pointing accuracy and capability of vibration isolation； therefore， numerical simulation and an experiment examining the control performance of the ASP system with cable and heat pipe additional connection are conducted. The Newton-Euler method is used to establish a multi-stage dynamic system. A mechanical model laying the foundation for effect analysis of the cable and heat pipe additional connection on the system is established. Numerical simulation is implemented to analyze the effect of additional connection on vibration isolation and stability of the system， providing theoretical support for satellite design and test. To gain more precise understanding of the effect of the additional connection， a full physical experiment is designed and conducted on the ASP control system. The result shows that the assembly layout of the cable and heat pipe additional connection has little effect on stability， pointing accuracy and setting time of the ASP control system. The assembly layout of the cable and heat pipe in the experiment provides a significant reference value and practical meaning for satellite design. An adaptive nonlinear control law with prescribed performance is proposed for dynamic coupling between the payload and platform. The simulation result shows that the controller considerably reduces the dynamic coupling and further improves the ability of fast maneuver， stable tracking and high precision pointing.