Effects of space radiation and molecular contamination on optics

Abstract

Molecular contamination and space radiation are known to degrade spacecraft performance, but the synergistic effects of the two are less understood. Optical systems are particularly vulnerable to degradation from exposure to contamination and/or space radiation. While traditional contamination assessments throughout the industry generally neglect radiation effects, our study demonstrate the importance of accounting for the space radiation environment when implementing contamination control. In this study, we investigate the impact of these complex degradation mechanisms on optical coatings. Our methodology consists of exposing optical coating coupons to flight-representative contamination and simulated space radiation environments, and we quantify the level of degradation by measuring the transmittance loss after each exposure. Our results show that the cumulative effects of molecular contamination and space radiation degrades optical performance more than either effect alone. In this report, we also discuss the effects of substrate and radiation exposure on the vacuum stability and morphology of the contaminant films.