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As next-generation precision space-based telescopes require larger and lighter weight mirrors, replicated composite optics are gaining increased attention as a route to decrease weight, cost, and manufacturing time over conventional glass mirrors. Despite numerous advantages of the replication technique, optical stability remains an issue since the optical layer is organic and susceptible to environmentally induced dimensional distortions that can cause deviations greater than SFE λ/20 (~32nm) allowed for these applications. Therefore, studies must be performed to investigate optical stability, specifically as a function of time due to long mission lifetimes. In this study, we manufactured replicated composite mirror coupons using a UV-cured epoxy at RT as a function of photoinitiator (PI) concentration. Subsequently, we monitored the optical changes of these mirrors as a function of time by laser interferometry. Residual stress was shown to be the primary driver in predicting optical performance since the magnitude of the stress was shown to be inversely related to replication quality. Changes occurring due to stress relaxation were also shown to negatively impact optical quality over time. A model was developed to optimize the final quality of the replication by controlling key processing parameters, including resin cure state, CFRP laminate thickness, and CFRP fiber stiffness. This understanding led to the development of a high-humidity cycling protocol used to eliminate all processing stress-induced distortions. This method has permitted the stabilization of replications for long-term storage by accelerating the stress relaxation phenomena and removing the driving force for optical change; the non-zero residual stress.
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