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A Microwave Enhanced Solid Waste Freeze Drying Prototype system has been developed for the treatment of solid waste materials generated during extended manned space missions. The system recovers water initially contained within wastes and stabilizes the residue with respect to microbial growth. Dry waste may then be safely stored or passed on to the next waste treatment process. Operating under vacuum, microwave power provides the energy necessary for sublimation of ice contained within the waste. This water vapor is subsequently collected as relatively pure ice on a Peltier thermoelectric condenser as it travels en route to the vacuum pump. In addition to stabilization via dehydration, microwave enhanced Freeze Drying reduces the microbial population (∼90%) in the waste.

The on-demand production of Medical Grade Water (MGW) is a critical biomedical requirement for future long-duration exploration missions. Potentially, large volumes of MGW may be needed to treat burn victims, with lesser amounts required to reconstitute pharmacological agents for medical preparations and biological experiments, and to formulate parenteral fluids during medical treatment. Storage of MGW is an untenable means to meet this requirement, as are nominal MGW production methods, which use a complex set of processes to remove chemical contaminants, inactivate all microorganisms, and eliminate endotoxins, a toxin originating from gram-negative bacteria cell walls. An innovative microgravity compatible alternative, using a microwave-based MGW generator, is described in this paper. The MGW generator efficiently couples microwaves to a single-phase flowing stream, resulting in super-autoclave temperatures.

A Microwave Powered Solid Waste Stabilization and Water Recovery Prototype system has been developed for the treatment of solid waste materials generated during extended manned space missions. The system recovers water initially contained within wastes and stabilizes the residue with respect to microbial growth. Dry waste may then be safely stored or passed on to the next waste treatment process. Using microwave power, water present in the solid waste is selectively and rapidly heated. Liquid phase water flashes to steam and superheats. Hot water and steam formed in the interior of waste particles create an environment that is lethal to bacteria, yeasts, molds, and viruses. Steam contacts exposed surfaces and provides an effective thermal kill of microbes, in a manner similar to that of an autoclave. Volatilized water vapor is recovered by condensation.

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.

The ability to aseptically remove samples and products, and the capability for addition of materials to sterile or otherwise microbially susceptible systems have always been compromised by the lack of a reliable means of sterilizing the mating fixtures. Cultures of mammalian cells are particularly vulnerable to microbial contamination due to the complexity of nutrient media and the lengthy periods required for cell growth. The Microwave Sterilizable Access Port has been developed to overcome this limitation. The system consists of three primary components: a microwave power source, a combined sterilization chamber/in-line valve port assembly, and a specimen transfer interface. Microwave energy is transmitted via coaxial cable to a small pressurized chamber that serves as a sterile transition between the surrounding environment and the system during transfer of materials.

Solid wastes can be separated from aqueous streams and concentrated by filtration in a magnetically assisted fluidized bed. In this work the filtration of solid waste materials using filter beds consisting of granular ferromagnetic media is demonstrated. The degree of bed consolidation (or conversely fluidization) is controlled by the application of magnetic forces. In the Magnetically Assisted Gasification (MAG) process, solids are first entrapped by filtration, and then fluidized and transferred to a high temperature reactor where they are thermally decomposed. The maximum particle loading for the filter bed is determined by the intergranular void space. Using magnetic methods, it is possible to manipulate the degree of compaction as the filtration progresses to increase the void space and thereby maximize the loading capacity and efficiency of the filter. This process is completely compatible with operation in microgravity and hypogravity.