REVERSE-OSMOSIS MODULE FOR SPACECRAFT WASHWATER RECYCLE

EXTENDED SPACE MISSIONS REQUIRE EXTENSIVE RECYCLING OF WATERTO PERMIT FREQUENT WASHING AND BATHING OF THE CREW. REVERSEOSMOSIS (RO), OFTEN CALLED HYPERFILTRATION, PROMISES TO BE A UNIQUELY SUITED TECHNOLOGY FOR WATER RECYCLING IN SPACECRAFT. HOWEVER, CURRENT MEMBRANE MODULE DESIGNS HAVE TWO MAJOR SHORTCOMINGS FOR THIS APPLICATION: (1) THEY ARE EASILY FOULED BY BACTERIA AND SUSPENDED MATTER FOUND IN WASHWATER, AND (2) THEY ARE RELATIVELY HEAVY. THIS EFFORT INVESTIGATES A NEW TYPE OF RO MEMBRAME MODULE BASED ON A TUBE-SIDE-FEED HOLLOW-FIBER MEMBRANE CONFIGURATION THAT OVERCOMES BOTH SHORTCOMINGS. POSITIVE FEED FLOW WITHIN THE HOLLOW-FIBER LUMENS IS EXPECTED TO MINIMIZE FOULING. BECAUSE THE FIBERS THEMSELVES SERVE AS PRESSURE VESSELS, NO HEAVY EXTERNAL PRESSURE VESSEL IS REQUIRED. IT IS ESTIMATED THAT A MODULE OF THIS DESIGN WOULD BE ABOUT 1/16 THE WEIGHT OF A CONVENTIONAL MODULE AND WOULD REQUIRE ABOUT 1/2 THE SPACE. THE PHASE I PROGRAM DEMONSTRATES THE FOULINGRESISTANCE OF THIS MODULE CONFIGURATION DURING PROLONGED TREATMENT OF ACTUAL WASHWATER USING WATER-DESALTING MODULES ALREADY UNDER DEVELOPMENT. A PROTOTYPE LIGHT-WEIGHT , HIGH PRODUCTIVITY MODULE SPECIFICALLY DESIGNED FOR WASHWATER RECYCLING IS CONSTRUCTED AND TESTED. BASED ON THE TECHNICALRESULTS, A DESIGN ANALYSIS OF RO FOR SPACE VEHICLE WASHWATERRECYCLING IS CONDUCTED.