2015-10-212015-10-212015-07-12ICES-2015-036http://hdl.handle.net/2346/64306Bellevue, WashingtonJohn Steele, UTC Aerospace Systems, USACarol Metselaar, UTC Aerospace Systems, USABarbara Peyton, UTC Aerospace Systems, USATony Rector, UTC Aerospace Systems, USARobert Rossato, UTC Aerospace Systems, USABrian Macias, NASA Johnson Space Center, USADana Weigel, NASA Johnson Space Center, USADon Holder, NASA/Marshall Space Flight Center, USAThe 45th International Conference on Environmental Systems was held in Bellevue, Washington, USA on 12 July 2015 through 16 July 2015.Water entered the Extravehicular Mobility Unit (EMU) helmet during extravehicular activity (EVA) #23 aboard the International Space Station on July 16, 2013, resulting in the termination of the EVA approximately 1-hour after it began. It was estimated that 1.5 liters of water had migrated up the ventilation loop into the helmet, adversely impacting the astronaut’s hearing, vision, and verbal communication. Subsequent on-board testing and ground-based test, tear-down, and evaluation of the affected EMU hardware components determined that the proximate cause of the mishap was blockage of all water separator drum holes with a mixture of silica and silicates. The blockages caused a failure of the water separator degassing function, which resulted in EMU cooling water spilling into the ventilation loop, migrating around the circulating fan, and ultimately pushing into the helmet. The root cause of the failure was determined to be ground-processing shortcomings of the Airlock Cooling Loop Recovery (ALCLR) Ion Filter Beds, which led to various levels of contaminants being introduced into the filters before they left the ground. Those contaminants were thereafter introduced into the EMU hardware on-orbit during ALCLR scrubbing operations. This paper summarizes the failure analysis results along with identified process, hardware, and operational corrective actions that were implemented as a result of findings from this investigation.application/pdfengPresentation