Testing and evaluation of an automated tether management system for microgravity extravehicular activities

To ensure safety during extravehicular activity (EVA), crewmembers must use tethers that constrain them and their tools to the spacecraft. A prototype automated tether system has been designed to increase the efficiency of such tether use. The system consists of a remotely releasable robotic gripper that serves to anchor the system, and a retractor that contains and controls the length of the tether in the workspace. In this paper, dynamic simulations of the system are derived and analyzed to predict retraction behavior in an orbital environment. The system was also tested using air bearing facilities to simulate a microgravity environment. Functional tests of the system are also discussed in order to characterize and quantify its performance.