Resource Aggregated Reconfigurable Control and Risk-Allocative Path Planning for On-orbit Assembly and Servicing of Satellites

Future spaceflight missions will require the use of distributed satellite systems, where multiple spacecraft must work in concert to manipulate, assemble, service, or function as a cohesive unit. Such spacecraft architectures must be able to capitalize on the resources of the system as a whole. Resource Aggregated Reconfigurable Control (RARC) techniques will enable satellites to control flexible, multi-body assemblies autonomously by adapting controllers in real time to changing mass, inertia, sensor, and actuator properties of the combined systems. As these systems maneuver throughout assembly or servicing processes, an algorithm called p-Sulu, or probabilistic Sulu, can plan risk-optimal paths around obstacles to rendezvous locations. RARC and p-Sulu are implemented using the Space Systems Laboratory’s Synchronized Position Hold Engage and Reorient Experimental Satellites (SPHERES) facilities at the Massachusetts Institute of Technology. SPHERES provides a platform for developing new controllers with the ability to rapidly modify and test control architectures while maintaining traceability to International Space Station testing and future spaceflight missions. Data captured from this testing shows that p-Sulu can successfully and robustly plan paths assuming a fixed horizon and specified risk bound. Furthermore, initial RARC algorithms show significant advancements in the ability to control the position and attitude of aggregate satellite systems when additional modules constitute a large percentage of system mass. Such abilities have clear traceability to future space missions in which satellites will cooperate autonomously to assemble and service onorbit spacecraft and structures.