Controllability of orbiting solar reflectors under structural failures

With global demand for clean energy growing, the concept of utilising space-based assets to deliver energy services is gaining attention. Orbiting solar reflectors present one possible solution, where sun-light can be re-directed onto terrestrial solar power farms allowing their operational hours to be extended. Given the large size of these structures, they are vulnerable to impacts of micro-meteorites, or indeed space debris. Additionally, should some part of the structure fail, there can be an increase in their flexibility, leading to questions over their controllability. This paper will investigate two types of structural failure: membrane degradation due to impacts which damage the reflective surface and joint failures in the structure. In the case of membrane degradation, a study is conducted into the resulting effect on desaturation schedules when the resulting asymmetry of the reflective structure leads to increased disturbance torques from solar radiation pressure. It will be shown that the highest rates of angular momentum accumulation occur when 50% of the membrane has been degraded, or damaged. A series of joint failures will then be studied. The increased flexibility of the structure, as a consequence of these failures, will lead to loss of controllability in all cases where actuation is limited by the capability of the overall structure to withstand control torques of up to 1750 Nm on each axis. If this constraint is removed, it will be shown that some cases of joint failures are still controllable by allowing higher control torques to meet the demands of the additional forces that increased flexibility of the structure brings to the system. • Orbiting solar reflectors. • Robustness to structural failure. • Effects of membrane degradation.