National Aeronautics and Space Administration
EVA 23 Suit Water Intrusion
1.4 Executive Summary On July 16, 2013, two US crew members (referred to here as EV1 and EV2) exited the International Space Station (ISS) US Airlock to begin U.S. Extravehicular Activity (EVA) 23. Roughly 44 minutes (Phase Elapsed Time) into EVA 23, EV2 reported water inside his helmet on the back of his head. The EVA ground team and EV2 were unable to identify the water’s source. As EV2 continued to work, the amount of water in the helmet increased and eventually migrated from the back of his head onto his face. EVA 23 was terminated early and the crew safely ingressed the airlock. The nominal rate was used to repressurize the airlock followed by an expedited suit doffing. The water quantity introduced into the helmet was estimated at 1 to 1.5 liters. During the post-EVA debrief, EV2 reported impaired visibility and breathing with water covering his eyes, nose, and ears. In addition, EV2 had audio communication issues because of the water. When returning to the airlock, EV2 had to rely on manual feel of his safety tether’s cable for pathway directions. The event was classified as a High Visibility Close Call and entered into the NASA Incident Reporting Information System (IRIS) as record number S-2013-199-00005. A related concern occurred during a post-EVA 23 suit dry-out procedure. A vacuum cleaner was used and unexpectedly suctioned O2 from the suit’s secondary high pressure oxygen tank, causing a potentially hazardous mix of electricity and pure O2, which could have ignited flammable materials in and around the vacuum cleaner. Fortunately, no incident of this nature was detected.
Figure 1-1. Extravehicular Mobility Unit (EMU) With Water in Helmet During Post-EVA 23 Screening Test The International Space Station (ISS) Extravehicular Activity (EVA) 23 Suit Water Intrusion High Visibility Close Call (HVCC) Mishap Investigation Board (MIB) was appointed on July 22, 2013 to gather information, analyze facts, identify the proximate cause(s), intermediate cause(s), and root causes that resulted in the mishap. In addition, the MIB was asked to comment on observations and contributing factors related to the mishap, and make recommendations that could be implemented within NASA to prevent a similar mishap from occurring in the future. It was not the intent of the MIB to place blame or
Published on Feb 27, 2014
Published on Feb 27, 2014
Report of the NASA Mishap Investigation Board examining the high visibility close call event of July 16, 2013 when ESA astronaut Luca Parmit...