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National Aeronautics and Space Administration


EVA23Water Intrusion

SI003 Local Training Issues/Programs

Local Training Issues/Programs are a factor when one-time or recurrent training programs, upgrade programs, transition programs or any other local training is inadequate or unavailable and this creates an unsafe situation. Local Training was investigated and found contributory to the HVCC. Evidence:

Transcripts from Audio Logs, Post EVA 23 Crew Debrief, Expedition 35/36 Post Flight Debrief, Post HVCC interview data from MOD EVA personnel

The approximate spare volume inside a space helmet is 12 liters empty, 8 liters when filled with a head and com cap. With so much empty space, it may not seem intuitive that by adding as little as one liter of water, an astronaut could aspirate water and drown. • Originally, engineers thought that water leaking into the helmet in zero gravity would stream down the front of the visor, like rain drops on a windshield. From there, the drops would follow the flow of air, eventually working their way into the body of the suit. • What was learned by this accident was that water from the vent loop tends to collect around the T2 port, which is near the back of the astronaut’s head. • Another lesson learned was that surface tension causes that water to remain in that area, sticking to the astronaut’s head. As more water accumulates, it gradually works its way forward, covering the ears, then the nose, and eventually the mouth, until the airway risks being compromised. • There is a purge valve on the side of the helmet, but water does not readily migrate to the valve when open. Water must be moved there by the Astronaut for it to be evacuated from the helmet. Finding: •

The manner in which water in the helmet would behave in zero gravity was neither intuitive, nor understood by the team members.


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...