Chemical Analysis of ISS Potable Water From Expeditions 8 and 9

With the Shuttle fleet grounded, limited capability exists to resupply in-flight water quality monitoring hardware onboard the International Space Station (ISS). As such, verification of the chemical quality of the potable water supplies on ISS has depended entirely upon the collection, return, and ground-analysis of archival water samples. Despite the loss of Shuttle-transferred water as a water source, the two-man crews during Expedition 8 and Expedition 9 maintained station operations for nearly a year relying solely on the two remaining sources of potable water; reclaimed humidity condensate and Russian-launched ground water. Archival potable water samples were only collected every 3 to 4 months from the systems that regenerate water from condensate (SRV-K) and distribute stored potable water (SVO-ZV). Because of the severely limited down mass on the Russian Soyuz vehicle, only a few potable water samples of less than 250 milliliters were actually returned to the ground with each crew. The chemical analyses that were performed on the returned samples were limited by the small sample volumes. Analytical results for the archival potable water samples returned from Expeditions 8 and 9 are reported in this paper and compared with ISS water quality specifications. Results from analyses of samples collected from the Service Module galley's hot and warm ports during Expeditions 8 and 9 indicated that the ISS system for regeneration of condensate water (SRV-K) produced acceptable quality potable water.