An important phase in On-Orbit servicing missions is robotic docking. Successful docking is subject to a number of parameters and conditions. In this work, the robotic impact docking between two space systems is considered. The docking of a robotic Chaser to a Target spacecraft is modeled using a multibody approach. The impedance properties required for an impedance controller that will ensure adequate probe-drogue contact time for docking are computed and are related with their mechanical counterparts. This time is derived analytically employing a mechanical equivalent system, and validated experimentally on a planar zero gravity emulator facility, allowing the selection of impedance parameters for successful docking.