Towards Robotic On-Orbit Assembly of Large Space Telescopes: Mission Architectures, Concepts, and Analyses

Over the next two decades, unprecedented astronomy missions could be enabled by space telescopes larger than the James Webb Space Telescope. Commercially, large aperture space-based imaging systems will enable a new generation of Earth Observation missions for both science and surveillance programs. However, launching and operating such large telescopes in the extreme space environment poses practical challenges. One of the key design challenges is that very large mirrors (i.e. apertures larger than 3m) cannot be monolithically manufactured and, instead, a segmented design must be utilized to achieve primary mirror sizes of up to 100m. Even if such large primary mirrors could be made, it is impossible to stow them in the fairings of current and planned launch vehicles, e.g., SpaceX’s Starship reportedly has a 9m fairing diameter. Though deployment of a segmented telescope via a folded-wing design (as done with the James Webb Space Telescope) is one approach to overcoming this volumetric challenge, it is considered unfeasible for large apertures such as the 25m telescope considered in this study. Parallel studies conducted by NASA indicate that robotic on-orbit assembly (OOA) of these observatories offers the possibility, surprisingly, of reduced cost and risk for smaller telescopes rather than deploying them from single launch vehicles but this is not proven. Thus, OOA of large aperture astronomical and Earth Observation telescopes is of particular interest to various space agencies and commercial entities. In a new partnership with Surrey Satellite Technology Limited and Airbus Defence and Space, the Surrey Space Centre is developing the capability for autonomous robotic OOA of large aperture segmented telescopes. This paper presents the concept of operation and mission analysis for OOA of a 25m aperture telescope operating in the visible waveband of the electromagnetic spectrum; telescopes of this size will be of much value as it would permit 1m spatial resolution of a location on Earth from geostationary orbit. Further, the conceptual evaluation of robotically assembling 2m and 5m telescopes will be addressed; these missions are envisaged as essential technology demonstration precursors to the 25m imaging system.