Investigation of the Makeup, Source, and Removal Strategies for Total Organic Carbon in the Oxygen Generation System Recirculation Loop

摘要

Since 2007, the Oxygen Generation System (OGS) on board the International SpaceStation (ISS) has been producing oxygen for crew respiration via water electrolysis. As wateris consumed in the OGS recirculating water loop, make-up water is furnished by the ISSpotable water bus. A rise in Total Organic Carbon (TOC) was observed beginning inFebruary 2011, which continues through the present date. Increasing TOC is of concernbecause the organic constituents responsible for the TOC were unknown and had not beenidentified; hence their impacts on the operation of the electrolytic cell stack components andon microorganism growth rates and types are unknown. Identification of the compoundsresponsible for the TOC increase, their sources, and estimates of their loadings in the OGA aswell as possible mitigation strategies are presented.