Contamination control program results from three years of ground operations on the Extreme Ultraviolet Explorer instruments

A stringent contamination-control plan has been developed for the optical components of the Extreme Ultraviolet Explorer instruments, whose performance in the 80-900 A wavelength range is highly sensitive to particulate and molecular contamination. The contamination-control program has been implemented over the last three years during assembly, test and calibration phases of the instrument. These phases have now been completed and the optics cavities of the instruments have been sealed until deployment in space. Various approaches are discussed which have been used during ground operations to meet optics' contamination goals within the project schedule and budget. The measured optical properties of EUV witness mirrors are also presented which remained with the flight mirrors during ground operations. These were used to track optical degradation due to contamination from the cleanroom and high-vacuum test-chamber environments.