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Iodine is the disinfectant used in U.S. spacecraft potable water systems. Recent long-term testing on human subjects has raised concerns about excessive iodine consumption. Efforts to reduce iodine consumption by Shuttle crews were initiated on STS-87, using hardware originally designed to deiodinate Shuttle water prior to transfer to the Mir Space Station. This hardware has several negative aspects when used for Shuttle galley operations, and efforts to develop a practical alternative were initiated under a compressed development schedule. The alternative Low Iodine Residual System (LIRS) was flown as a Detailed Test Objective on STS-95. On-orbit, the LIRS imparted an adverse taste to the water due to the presence of trialkylamines that had not been detected during development and certification testing. A post-flight investigation revealed that the trialkylamines were released during gamma sterilization of the LIRS resin materials.

Feasibility of the use of microwave heating to achieve fast and efficient thermal regeneration of sorbents for the removal of carbon dioxide, water vapor, and trace organics from contaminated air streams has been conclusively demonstrated. The use of microwave power offers several advantages, including: improved heat transfer, lower thermal losses, improved power utilization, and enhanced operational capabilities. During the initial research, the sorption and microwave-powered thermal desorption of acetone, trichloroethylene (TCE), carbon dioxide, and water vapor was studied at 2.45 GHz using a rectangular waveguide based test apparatus. Both activated carbon and Carbosieve S-III were identified as excellent microwave regenerable sorbents for use in the removal of airborne organics. Water loaded silica gel, Molecular Sieve 13X, and Molecular Sieve 5A were also effectively regenerated under microwave irradiation at this frequency.