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National Aeronautics and Space Administration

EVA23Water Intrusion

The background and circumstances of the ground team’s response to the early CO2 sensor failure created a series of human factors issues that hindered the ability of the crew and ground to recognize that the water in the helmet could have been caused by a much more significant source than the DIDB. Identifying these issues involves assessing available evidence to understand how and why the ground team and the crew team struggled to diagnose systematically the source of the water leak and misjudged the potential severity of the overall situation. The ground team did not realize that there might be a problem with the suit itself, and therefore selected a course of action focused on mitigating leaks from the DIDB at the expense of investigating potential issues with the suit. The team maintained a narrow focus (channelized attention) on the problem without considering all the potential causes for an off-nominal amount of water in the helmet. The crew and the ground teams were both unaware of all potential causes of water leaks, especially water coming from the vent loop. The CO2 failure, water leaking into the helmet, and the potential anti-fog eye irritation all happened around the same time, contributing to cognitive oversaturation to particular individuals. Additionally, evidence shows that the ground team and the crewmembers were accustomed to seeing CO2 sensors fail, and experiencing limited and manageable amounts of water in the helmet. The following section addresses some of the most relevant human factors of this event in greater detail.


ISS EVA Suit Water Intrusion Mishap Investigation Report  

Report of the NASA Mishap Investigation Board examining the high visibility close call event of July 16, 2013 when ESA astronaut Luca Parmit...