Initial space food crops will be “pick-and-eat”, requiring produce disinfection on board spacecraft. The state of the art disinfection method on the ISS is Pro-San® wipes developed by Microcide, Inc. This method is not regenerable, requiring resupply mass, creating solid waste, and requiring crew time to manually clean vegetables. Also, wipes cannot easily disinfect produce with a lot of crevices, such as leafy vegetables or radishes. Other disinfection methods investigated by researchers have included hydrogen peroxide and cold plasma, which both negatively impact food quality. Chemical methods that produce toxic by-products or residues on the produce are unacceptable solutions. UV for disinfection is also problematic, as light does not easily penetrate crevices in the produce surface. Space Lab Technologies, LLC proposes Produce Wash and Aeration for Space Habitats (Pro-WASH™), a hybrid ozonating and Pro-San® water wash system for on-board produce disinfection. Pro-Wash™ offers several innovative features relative to state-of-the-art. It is an autonomous and versatile. It not only disinfects, but also optionally rinses, steams, and dehydrates produce. A gently spinning, grated wash basket increases the contact of wash fluid with vegetable surfaces and crevices. An ozone generator diffuses safe levels of re-generable ozone into the wash-water stream for disinfection without noticeable reduction in food quality. Optionally, a Pro-San® wash water solution provides an alternate disinfection method. A self-cleaning mode reduces crew time needed for maintenance and increases long term reliability. Pro-WASH™ operates across gravity regimes (0-1 g). Finally, the design is extensible to disinfection of non-produce items, such as utensils, toothbrushes, laundry, etc. In Phase I, Space Lab will combine conceptual design and analysis with prototype development and testing to establish technical and economic feasibility for produce disinfection with Pro-WASH™.
ProWASH™ would be useful in several NASA human exploration programs including ISS operations, Deep Space Gateway missions, and future surface missions (to the moon or Mars). The resource use efficiency, reliable design, and versatility of the Pro-WASH™ system will make it an attractive addition to any spacecraft or surface habitat. The design might also be simplified to support science experiments needing to separate liquids from solids, and to make mass measurements in microgravity.