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The International Space Station (ISS) Internal Active Thermal Control System (IATCS) uses a water based heat transport fluid with specific chemical parameters and additives for corrosion and microbial control. The fluid and hardware have experienced anomalies since activation of the United States Laboratory (USL), including chemical and possibly, microbial corrosion. The required sampling of the fluid has the crewmembers removing samples via an in-line sampling tool to perform real-time trace ammonia contamination tests using color change strips, and filling a 150 ml bag from each loop for the ground laboratory analyses. The former activity requires stable storage of the strips, and for the latter activity, it is highly desirable to return the ground sample as stable as possible. This paper describes the process for materials selection, test methods/set-up, results, and final recommendation for a replacement outer bag.

The potential for a catastrophic hazard occurring on the International Space Station United States on-orbit segment exists due to using a single barrier heat exchanger as the interface between external active thermal control systems and the internal active thermal control systems of the habitable elements and the incompatible maximum design pressures of the respective systems. Pressurized ammonium hydroxide may engulf crewmembers if proper controls are not designed into the integrated system. Engineering review and analyses were made to determine the failure mechanisms and recommend controls to mitigate the hazard and lower the risk to a program acceptable level.