July 18, 2013
Cause Of Leaky Spacesuit Still A Mystery For NASA Astronauts
Lawrence LeBlond for redOrbit.com - Your Universe Online
A spacewalk that ended prematurely due to a leaky helmet on Tuesday, July 16 is still under investigation, and NASA officials said they still do not have an answer as to what happened.
Mission Control ended the extra-vehicular activity (EVA) outside the International Space Station on Tuesday after Italian astronaut Luca Parmitano reported a buildup of water in the back of his helmet. The accumulation continued to a point where water began to collect around his face and after American astronaut Chris Cassidy, who was also on the external mission, confirmed the leak, the spacewalk was wrapped up.
The spacewalk was officially ended at one hour and 32 minutes, making it the second shortest spacewalk in ISS history. Tuesday's mission was scheduled to address a number of issues, but only two tasks were completed before Parmitano reported a CO2 sensor issue on his suit.
David Korth, lead flight director for the spacewalk, described the leak as a "gush" or "bubble" of water, according to the Washington Post.
Korth noted that the CO2 sensor issue was attributed to the water buildup. It was initially determined that Parmitano should continue his tasks, but after Cassidy reported that the water in the helmet was coming around Parmitano's ears and the side of his face, Korth made the call to terminate the spacewalk.
"It wasn't prudent to try to continue tasks," given Parmitano's discomfort, Korth said. "It was clear that he was having trouble."
From the time the call was made to end the spacewalk to the time the two astronauts entered the airlock, roughly 20 minutes had passed. By this time, it was ascertained that even more water was accumulating inside Parmitano's helmet. In all, roughly 1.5 quarts of water had accumulated in Parmitano's suit, mostly in the helmet.
"It's a good day today. The crew is inside and safe," said Karina Eversley, lead spacewalk officer, shortly after the crew returned to the comfort of the orbiting lab.
Initial thoughts were that Parmitano's drink bag, which holds 32 ounces, was the source of the leak. However, Parmitano reported a funny taste to the water, potentially ruling out his water supply as the culprit. Korth noted that sweat may have been a source, yet the volume of water inside the suit was too large for that to be the case. The other possibility was the suit's cooling and ventilation system, which holds about a gallon of water
Eversley said that this is a first. "We have not seen a problem like this before." She said anti-fog is sometimes an issue, and it can be painful if it gets in the eyes, but even that produces limited amounts of water.
The amount of water in Parmitano's cap made it impossible for him to hear. If there was enough water in there, it could have caused him to drown, explained Eversley to Emi Kolawole of the Washington Post.
Parmitano came out of it okay, however. He took to his Twitter account sometime later to let the world know he was doing okay. "Thanks for all the positive thoughts! Ringrazio tutti per avermi avuto nei loro pensieri!" he said on his feed.
Parmitano also conducted an exhaustive troubleshooting procedure on his spacesuit in the Quest airlock, according to a NASA statement. "He activated the suit on its rack in the Equipment Lock, began to recharge the suit with water and inspected every nook and cranny for signs of water leakage, but no leakage was immediately noticeable other than some inconclusive droplets."
Meanwhile, engineers in Houston conducted their own investigation into the leak. But more than a day after the harrowing incident, a clear answer has eluded the experts.
Parmitano had worn the same suit on a July 9 spacewalk without mishap.
"Back to normality on the ISS - Cupola is still a fantastic sight, even after a (very short) EVA," Parmitano tweeted Wednesday.
During Parmitano's investigation of his suit, nothing suspicious popped up, said Humphries. However, since there are only two sources of water on the suit, it has to be one of the two. Since NASA ruled out the drink bag, the cooling system must be the culprit. Humphries noted that specialists detected a higher than normal amount of water usage from the system's tanks, which is consistent with Tuesday's mishap.
"No real theory yet on exactly where this water came from or why, but they are doing a very deliberate step by step process of troubleshooting to try to identify what's going on," he said.
As long as no emergencies pop up, NASA said it has no plans for any EVA missions in the near future. The work left undone on Tuesday involved minor chores that had just piled up over the past few years. There is no rush to finish the job, noted officials.
But emergencies do happen. Just two months ago, astronauts had to perform an emergency spacewalk to repair an ammonia leak first spotted by ISS crew members on May 9, 2013. That walk, like most, went off without a hitch.
NASA praised Parmitano's calm, cool demeanor during Tuesday's crisis. A major in the Italian Air Force and former test pilot, Parmitano arrived at the orbiting lab at the end of May. He is scheduled to remain aboard the ISS until November.