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ECLSS Sustaining Compatibility Testing on Urine Processor Assembly Nonmetallic Materials for Reformulation of Pretreated Urine SolutionOn International Space Station (ISS), the Urine Processor Assembly (UPA) converts human urine and flush water into potable water. The urine is acid-pretreated primarily to control microbial growth. In recent years, the sulfuric acid (H2SO4) pretreatment was believed to be largely responsible for producing salt crystals capable of plugging filters in UPA components and significantly reducing the percentage of water recovery from urine. In 2012, ISS management decided to change the acid pretreatment for urine from sulfuric to phosphoric with the goal of eliminating or minimizing formation of salt crystals. In 2013-2014, as part of the qualification of the phosphoric acid (H3PO4) formulation, samples of 12 nonmetallic materials used in UPA components were immersed for up to one year in pretreated urine and brine solutions made with the new H3PO4 formulation. Dynamic mechanical analysis (DMA) was used to measure modulus (stiffness) of the immersed samples compared to virgin control samples. Such compatibility data obtained by DMA for the H3PO4-based solutions were compared to DMA data obtained for the H2SO4-based solutions in 2002-2003.
Document ID
20150021400
Acquisition Source
Marshall Space Flight Center
Document Type
Technical Publication (TP)
Authors
Wingard, C. D.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
November 19, 2015
Publication Date
September 1, 2015
Subject Category
Nonmetallic Materials
Man/System Technology And Life Support
Report/Patent Number
NASA/TP-2015-218212
M15-4854
M-1401
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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