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Columbus has been delivered to Kennedy Space Center (KSC) in summer 2006 for final integration, test and mission preparation. In the frame of these “last” phase activities also the Active Thermal Control System (ATCS) had to be finalized and prepared for the launch resp. mission. Due to unexpected late failures resp. malfunctions detected on component/unit level of the ATCS, refurbishment, integration / exchange of the relevant components and re-testing of their system level functions had to be done. Moreover, the still outstanding system level fluid leakage test of the ATCS had to be revised and completed. In addition to the required late refurbishment, integration and test activities, in certain cases also operational workarounds had to be evaluated. They should help to cope with similar contingency situations during operation of the ATCS on-orbit.

To identify the most significant parameters influencing the cosmetic corrosion of cold-rolled and coated steel sheets, stretch deformed panels were phosphated, painted and exposed in real time on an experimental car for 5 years. Based on advanced microanalysis techniques, the morphologies and the chemical composition of the corrosion salts are characterized. Comparisons between accelerated tests and natural exposures are made and corrosion mechanisms are identified. On that basis, a 3-step cyclic model of cosmetic corrosion is presented. Combined with the experimental results, this model outlines the importance of the coating characteristics, the compositions of the corrosion products, the humidity and temperature cycles during the exposure tests (natural or accelerated) and the environmental conditions (salts and polluting gases) on the corrosion mechanisms and the resistance of painted coated steels.