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The technology selected for waste processing has a major effect on system closure and mission equivalent system mass (ESM). In particular, recovery of the water content of solid waste can make the difference between a mission being water poor and water rich. Potential alternative sources of water that need to be considered would include recovery of water from carbon dioxide reduction, and in situ resources. This paper looks at a range of waste-processing scenarios and calculated system ESM impacts related to these options. The lowest ESM approach is generally storage or dumping. However, other issues also need to be considered. Processing may be driven by requirements such as the need to recover commodities like water, prevent release of toxic gases into the spacecraft environment, planetary protection requirements, and interface loads.

Increased nickel concentrations in the IATCS coolant prompted a study of the corrosion rates of nickel-brazed heat exchangers in the system. The testing has shown that corrosion is occurring in a silicon-rich intermetallic phase in the braze filler of coldplates and heat exchangers as the result of a decrease in the coolant pH brought about by cabin carbon dioxide permeation through polymeric flexhoses. Similar corrosion is occurring in the EMU de-ionized water loop. Certain heat exchangers and coldplates have more silicon-rich phase because of their manufacturing method, and those units produce more nickel corrosion product. Silver biocide additions did not induce pitting corrosion at silver precipitate sites.