Tethered systems in ADR: Satleash microgravity experiment and future developments

Tethered space systems are becoming a very appealing research field in the last years. The main reason is that they offer a wide range of applications. Several different kind of missions, such as Active Debris Removal and LEO satellites disposal could exploit this technology. However, a tether is an highly flexible element that undergoes many instability phenomena. This is particularly true in mission scenarios in which an active chaser excites the stack dynamics. This paper presents the results of the SatLeash experiment that was selected to fly in microgravity conditions by the ESA FlyYourThesis! 2016 programme. The main goals of the experiment were to validate the dynamical simulator and to verify the implemented control law to stabilize the tethered space system. A reduced-scale tethered floating test bed was developed for the parabolic flight campaign. Different tether stiffness have been tested as well as control schemes. A wave-based control, using tension feedback, resulted to be an effective method to stabilize the system during tensioning and release phases. This paper presents the results of the experimental validation along with an overview of the future technology development road-map.