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A new technology for controlling the partial pressure of CO2 (pCO2) in a plant growth chamber (PGC) has been demonstrated. CO2 is gathered from the source atmosphere across a membrane gas exchanger and stored in an alkanolamine solution. The CO2 loading of the alkanolamine reservoir is monitored using specific conductance and controlled by the exposure time and temperature. The PGC pCO2 is maintained using a second membrane exchanger through which the alkanolamine circulates, absorbing or releasing CO2 to maintain equilibrium. The equilibrium pCO2 is determined by the CO2 loading and the temperature. Constant PGC feed pCO2 levels of roughly 1000 ppm have been maintained using sources with pCO2 both above and below this value.

Unibeds®* are multimedia layered sorption beds baselined for use in the Space Station Freedom (SSF) water reclamation system. Unibeds® must be sterilized prior to use to avoid the introduction of bacteria into the water reclamation system when the Unibeds® are routinely changed out. In the past, Unibeds® were autoclaved in an attempt to achieve sterility. Some sorbent media used in the Unibeds® decompose when exposed to high temperatures for extended periods. Although no significant sorbent decomposition occurs during the routine autoclave time of 30 minutes, it is uncertain whether sufficient sterilization temperatures are achieved at the Unibed® core. Gamma irradiation has been evaluated as a practical alternative method to achieve sterility and eliminate possible sorbent thermal degradation. Sorbent media were inoculated with irradiation resistant spores (106 CFU/ML) of bacterium Bacillus pumilus and subsequently exposed to radiation doses of 1.5, 2.0, and 2.5 megarads (Mrad).

The Microbial Check Valve (MCV) is a reloadable flow-through canister containing iodinated ion exchange resin, which is used aboard the Shuttle Orbiter as a disinfectant to maintain water potability. The MCV exhibits a significant contact kill and imparts a biocidal residual I2 concentration to the effluent. MCVs in current use have nominal 30 day lives. MCVs baselined for Space Station Freedom will have 90 day lives, and will require replacement 120 times over 30 years. Means to extend MCV life are desirable to minimize resupply penalties. New technology has been developed for fully autonomous in situ regeneration of an expended MCV canister. The Regenerative Microbial Check Valve (RMCV) consists of an MCV, a packed bed of crystalline I2, a flow diverter valve, an in-line iodine monitor and a microcontroller. During regeneration, flow is directed first through the packed I2 bed and then into the MCV where the resin is replenished.

This paper describes a newly designed, 2.7 Kg (6 pound) capacity, laundry machine called the Single Phase Space Laundry (SPSL). The machine was designed to wash and dry crew clothing in a micro-gravity environment. A prototype unit was fabricated for NASA-JSC under a Small Business Innovative Research (SBIR) contract extending from September 1990 to January 1993. The unit employs liquid jet agitation, microwave vacuum drying, and air jet tumbling, which was perfected by KC-135 zero-g flight testing. Operation is completely automated except for loading and unloading clothes. The unit uses about 20 percent less power than a conventional household appliance.

The Microbial Check Valve (MCV) is a canister containing an iodinated ion exchange resin and is used on the Shuttle Orbiter to provide microbial control of potable water. The MCV provides a significant contact kill, and imparts a biocidal iodine residual to the water. The Orbiter MCV has a design life of 30 days. For longer duration applications, such as Space Station Freedom, an extended life is desirable to avoid resupply penalties. A method of in situ MCV regeneration with elemental iodine is being developed. During regeneration water en route to the MCV first passes through a crystalline iodine bed where a concentration between 200 - 300 mg/L I2 is attained. When introduced into the MCV, this high concentration causes an equilibrium shift towards iodine loading, effecting regeneration of the resin. After regeneration normal flow is re-established. Life cycle regeneration testing is currently in progress.