Visual inspection of ATV

ATV's particulate control team follows common ‘Space Station Programme’ requirements detailing the acceptable conditions of habitable internal ISS surfaces as well as air quality. Checking surfaces comes down to close-up visual inspection to a set distance and angle, backed up by bright lighting, to ensure they are contamination-free to a set ‘visibly clean – sensitive’ level. Crucial outside surfaces are checked to an equivalent level, including all optical instruments – such as laser range finders as well as star trackers – onboard thrusters and the docking system with ISS: any layer of dust might prevent a solid seal from forming. This image shows the visual inspection of the ATV-4 interior.