NASA Investigating Another Water Intrusion into Spacesuit During EVA

NASA Investigating Another Water Intrusion into Spacesuit During EVA

NASA is investigating how water got into astronaut Tim Kopra’s spacesuit during a spacewalk on Friday.  The spacewalk was terminated early after Kopra reported that a small bubble of water was floating in his helmet and an absorbent pad behind his head was wet.

The incident is reminiscent of a more serious water incursion when European Space Agency (ESA) astronaut Luca Parmitano was performing a spacewalk in July 2013.  NASA at first assumed the water Parmitano reported in his helmet came from his drink bag, but the quantity continued to increase and eventually covered his ears, eyes and mouth as he worked his way back to the safety of the airlock.  He remained calm throughout the ordeal, but wrote about it afterward saying that he felt “like a goldfish in a fishbowl.”

NASA later determined that the water was from the spacesuit’s cooling system that regulates the astronaut’s temperature when on a spacewalk — or extravehicular activity (EVA).  The temperature changes dramatically as the International Space Station (ISS) circles the Earth every 90 minutes, moving from blistering sunlight to frigid cold.  NASA determined that a clogged filter in a fan separator unit allowed the cooling water to make its way into the spacesuit itself — something thought to be impossible until then.  A Mishap Investigation Board identified five organizational root causes, apart from technical problems, that contributed to that life threatening incident.

As a contingency, the astronauts now place a Helmet Absorption Pad (HAP) — similar to a diaper — in the back of their helmets to absorb any water that might get in.  They also have a type of snorkel that would allow them to breathe even if water covered their nose and mouth.   Without gravity, water attaches itself through surface tension and there is no way to get rid of it without wiping it off, which is impossible to do when inside a spacesuit.

Parmitano’s spacewalk partner that day was NASA astronaut Chris Cassidy, who is now head of the astronaut office at Johnson Space Center.   On Friday, Cassidy quickly directed that the spacewalk be terminated after Kopra reported on the size of the bubble and the fact that the water was cold.  That indicated the water was not from the drink bag, but the cooling system in the backpack.

Cassidy said the size of the bubble (a half-inch wide and 2-3 inches long) and the fact that the HAP was “squishy” were troubling, but “for me the big hook” was the temperature of the water: “as soon as you can tell it is cold water …. that’s coming from a source in your backpack and that’s a significant concern for us.” 

The two astronauts directly made their way back to the airlock.   NASA astronaut Scott Kelly, who was inside the ISS during the EVA, helped Kopra get out of his spacesuit and tried to capture any loose water bubbles and put the HAP into a bag for later analysis to help engineers determine the leak rate.  Cassidy said there should be no water in the HAP at all unless an astronaut is perspiring profusely.

Kopra and ESA astronaut Tim Peake were performing the spacewalk to replace a failure voltage regulator — a Sequential Shunt Unit or SSU — and that was accomplished successfully.  They were beginning to do some additional tasks when the spacewalk was terminated.   The total duration was 4 hours 43 minutes.

CBS News space correspondent BIll Harwood tweeted that the suit Kopra was wearing on Friday is the same one that Parmitano wore in July 2013, but that the fan separator unit thought to be at fault was replaced and the spacesuit cleaned and inspected.  It was used without incident on a spacewalk in December.

NASA made no official announcement about the problem, but said in its space station blog that “[t]eams will continue to look over data collected during the spacewalk and discuss forward plans in the days to come.” A link to an audio recording of Cassidy’s comments are in that blog post.

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