Compensation of general asymmetric static loads for a complete optical system of freeform mirrors

Optical systems consisting of freeform metal mirrors are state of the art in optical engineering. Thefreeform shapes allow for more compact designs and offer more degrees of freedom for aberration correction.Themetal components allow to relocate effort from the integration to the fabrication stage. Metalmirrors for spaceborne optical systems experience several loads during orbital commissioning or operation.The present article focuses on describing general static loads within the optical design to close theiteration loop between optical and mechanical design using this knowledge to investigate how to compensateload induced surface shape errors within the optical design. First, this analysis is performed fora two mirror system with an asymmetric force load step. Second, the compensation of this load is discussedby performing another optical design step or a direct mechanical compensation step at mechanicaldesign level. Since thermal loads usually introduce expansion effects, a third point of the article is thediscussion of thermal loads with some general results, to embed them into the shown formalism. Thearticle concludes by showing residual optical errors of the compensated optical system and comparingthem with the nominal design.