Assembly of large lenses for space systems via solder jet bumping technology

The qualification and robustness of optomechanical systems for large lenses in space environments are increasingly challenging, especially for next-generation Earth observation missions with strict performance requirements, such as precise lens positioning and long-term stability. Soldering offers a promising alternative to adhesives. and technologies like Solderjet Bumping (SJB) are being explored to meet these demands. To evaluate SJB's performance, three optic-mount material sets (SQ1-INVAR. LaK9-Titaniiun. and CaF2-Stainless Steel 1.4571) were tested using SAC305 solder alloy. The optical performance and alignment were assessed through CAD simulations and experimental characterization, including interferometiy and polarimetiy. Results show that component geometry and design significantly affect performance, and soldering has minimal impact on optical quality, even in high-impact environments. However, materials with different crystal orientations, like CaF2. play a crucial role in their performance, as different orientations react differently to stress, leading to localized damage during soldering.