Potable Water Treatment and Transfer from Shuttle to Mir

To satisfy a requirement to supply water to Mir station, a process for treating iodinated water on the Shuttle was developed and implemented. The treatment system consists of packed columns for removing iodine and a syringe-based injection system for adding ionic silver, the biocide used in Mir water. Technical and potable grade water is produced and transferred in batches using collapsible 44-liter contingency water containers (CWCs). Silver is added to the water via injection of a solution from preloaded syringes. Minerals are also added to water destined for drinking. During the previous four Shuttle-Mir docking missions a total of 2781 liters (735 gallons) of water produced by the Shuttle fuel cells was processed using this method and transferred to Mir.

To verify the quality of the processed water, samples were collected during flight and returned for chemical analysis. Results show that iodine and related species were removed effectively by the activated carbon and ion exchange treatment system. Target concentrations of silver, fluoride, calcium and magnesium were reproducibly obtained. A discussion of problems encountered during the first flight of the treatment system, and the changes made for subsequent flights, are presented. Potential future applications of this hardware for the International Space Station are also discussed.