Communication architecture evaluation for real-time tele-operated spacecraft

Real-time Tele-operation (RTTO) is a control concept for tasks in which in-situ manipulations by humans are not feasible (e.g. dangerous environmental conditions), and autonomous control is demanding due to complex tasks and unforeseeable problems arising during mission conduct. Possible applications of RTTO in space vary from debris removal, using robotic spacecraft to on-orbit servicing of existing satellites. One key challenge in the design of a RTTO spacecraft is the communication architecture that provides a high data rate, low-latency bi-directional information transfer between the satellite and the human operator. This paper proposes an extended definition of communication architectures. The proposed definition defines not only the orbital positions and main specifications of all elements of a communication link, but among other parameters includes also the required performance of data processing/transfer within the spacecraft and between all relay nodes. Possible orbital constellations of servicer, relay nodes and ground stations are analyzed and network topologies can be evaluated. Subsequently the link performance is investigated measuring achievable data rates, round trip delays and bit error rates in an end-to-end hardware-in-the-loop simulation including a real world space link.