The OSIRIS camera system on board the ESA Rosetta mission to comet 46P/Wirtanen will carry interference filters with glass substrates. During the long cruise phase the probe will be immersed into an environment of energetic particles, especially when the trajectories of solar coronal mass ejections will be traversed. We have studied the effects on the transmission curves of clear and colored glasses of such MeV proton bombardment, using laboratory simulations covering the expected range of fluence. As a result, while Quartz Suprasil glass was radiation hard for all considered does, Schott OG590 and KG3 glasses showed reductions in transmission up to 5-10 percent though only for doses exceeding the expectance for Rosetta. Furthermore, about half the effect was annealed away at room temperature with a time constant of the order of one day.
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