Optimum design of freeform-enabled space optical instruments

Abstract

Nowadays space missions rely heavily on optical payloads to carry out a wide range of tasks including earth observation, weather monitoring, astrophysics research and communications. Until recently, the design of such systems was done according to design principles such as rotational symmetry as it simplifies the theory, reduces technological risks, manufacturing costs and cuts down assembly, integration and testing efforts.

Nevertheless, the ever-growing need to develop more compact and lightweight payloads with enhanced performance often forces designers to adopt tilted off-axis configurations which break the rotational symmetry of the system. In such circumstances, rotationally symmetric optical surfaces cannot compensate the
tilt-induced optical aberrations and thus no longer provide optimum performance over the complete field of view. The solution to this problem is to abandon the conventional approach and adopt a new design paradigmbased on the use of non-rotationally symmetric surfaces, also known as freeform optics.

Most of the state-of-the-art methods used for the design of conventional optical payloads are not entirely suitable for freeform optics because: first of all, they were developed on the basis of rotational symmetry (which is no longer applicable) and secondly, because they do not cope well with the large amount of additional degrees of freedom that freeform optics usually entails. Therefore, this Master Thesis was devoted to the development of a novel methodology for the design and optimization of payloads based on freeform optics.