Active In-Situ Contamination Control

In-situ CO2 jet spray cleaning technology will be advanced for application to cleaning of Space Based Laser (SBL) optics in space. The program will provide a database on performance when cleaning in a confined volume under vacuum conditions. Experimentswill be performed cleaning aluminum and silicate dust particles from silicon and sapphire substrates having top layer coatings of ZnSe, an oxide and a fluoride. These contaminant and surface types are of high interest to SBL and other high energy laserprograms. The experiments will collect particle count, absorption and scatter data before and after in-situ cleaning of the parts. Some parts will be cleaned multiple times to detect any potential change in optical performance due to multiple cleanings.The goal is to demonstrate consistent cleaning to below level 200 (50 PPM area obscuration) and explore the limits of cleaning when the starting surface cleanliness is around level 500. Phase 1 indicates this limit may be below level 100 (10 PPM areaobscuration). Additionally, in-vacuum cleaning of an 8 inch diameter optic will be demonstrated and special studies will be performed to assess particle migration and the actual cleaning footprint from a single jet spray nozzle.