Crew Exploration Vehicle (CEV) Potable Water System Verification Coordination 2008-01-2083
The Crew Exploration Vehicle (CEV), also known as Orion, will ferry a crew of up to six astronauts to the International Space Station (ISS), or a crew of up to four astronauts to the moon. The first launch of CEV is scheduled for approximately 2014.
A stored water system on the CEV will supply the crew with potable water for various purposes: drinking and food rehydration, hygiene, medical needs, sublimation, and various contingency situations. The current baseline biocide for the stored water system is ionic silver, similar in composition to the biocide used to maintain quality of the water transferred from the Orbiter to the ISS and stored in Contingency Water Containers (CWCs). In the CEV water system, the ionic silver biocide is expected to be depleted from solution due to ionic silver plating onto the surfaces of the materials within the CEV water system, thus negating its effectiveness as a biocide. Since the biocide depletion is expected to occur within a short amount of time after loading the water into the CEV water tanks at the Kennedy Space Center (KSC), an additional microbial control is a 0.1 micron point of use filter that will be used at the outlet of the Potable Water Dispenser (PWD).
Because this may be the first time NASA is considering a stored water system for long-term missions that does not maintain a residual biocide, a team of experts in materials compatibility, biofilms and point of use filters, surface treatment and coatings, and biocides has been created to pinpoint concerns and perform testing to help alleviate those concerns related to the CEV water system. This paper will focus on the holistic integration of expert knowledge from each of these disciplines. This paper details present and future work that will be used to determine how to mitigate the risks associated with meeting water quality and microbial requirements levied on the CEV stored water system throughout each mission.