Abstract: Since 1989 Hughes has been investigating ion cleaning of contaminant films from spacecraft optics while on-orbit. Two of the most successful methods of ion cleaning without damage have been developed on the Advanced Removal Techniques by Ion Cleaning (ARTIC) Program. The first method utilizes energetic electron sputtering, and the second method utilizes low-energy oxygen ion (LEOI) reactive etching. We have successfully removed water, ammonia and carbon dioxide cryofilms with electron sputtering. The mirror materials being cleaned include bare beryllium and protected aluminum coated optics. No damage to these ultra-low-scatter mirror materials has been observed even when the mirrors are purposely over-cleaned with electrons by many orders of magnitude. Current electron cleaning rates are on the order of 200 angstroms per minute over approximately a 50 cm diameter area. A broad- beam of electrons from a flight-qualified Penning discharge source is being used for the electron cleaning, so no rastering is necessary. Low-energy oxygen-ion cleaning is being used to reactively clean organic films. Since the energy of the ions is much lower than the sputter threshold of the mirror materials, the mirror materials cannot be damaged using this technique. The current cleaning rates are on the order of 20 angstroms per minute over approximately a 10 cm diameter area. A broad-beam flight-prototype ion source is being used that has been developed by the Hughes Research Laboratories for extremely long life, low power applications.!3
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