Last year's near-drowning of Italian spacewalker Luca Parmitano could have been avoided if earlier warning signs were heeded, investigators said in a NASA report issued Wednesday.
The crisis cropped up last July 16 while Parmitano and NASA astronaut Chris Cassidy were conducting a spacewalk to perform routine cable work at the International Space Station. About 45 minutes into the operation, Parmitano reported that water was quickly building up inside his helmet — and clinging to his face.
By the time the spacewalkers came back inside the station, water was getting into Parmitano's eyes, nose and mouth. If the situation had gone on much longer, he could have drowned in his suit, NASA officials said afterward.
The cause of the leak was traced to contamination that blocked a water separator inside Parmitano's spacesuit. Chris Hansen, NASA's chief engineer for the space station and head of the agency's Mishap Investigation Board, said Parmitano actually encountered a similar but less serious problem with the suit during a previous spacewalk.
'Not properly investigated'
"The event was not properly investigated, which could have prevented putting a crew member at risk a week later," Hansen told reporters. He said the station's crew members and ground controllers assumed that the earlier water problem was caused by a leaky drink bag, and that the July 16 problem was less serious than it turned out to be.
Hansen acknowledged that the water separator problem was subtle. "This kind of failure wasn't really expected," he said. It took the investigators weeks to determine conclusively that the two problems were caused by the same equipment failure, he said.
The report said another potential concern arose when the crew worked to dry out Parmitano's suit after the July 16 spacewalk. "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 O2," it said.
That mix could have sparked a fire. "Fortunately, no incident of this nature was detected," the report said.
The investigation board issued a set of 49 recommendations to address the concerns raised by last year's incident. The high-priority items include quicker and better dissemination of information about spacesuit problems, and better procedures for dealing with water in a spacesuit helmet as well as for terminating a spacewalk early.
"We've already resolved many of these items," said Bill Gerstenmaier, NASA's associate administrator for human exploration and operations. He pointed out that contingency NASA spacewalks were conducted successfully on the space station in December.
Mike Suffredini, NASA's manager for the space station program, said all of the high-priority recommendations are due to be implemented by June, and the rest will be addressed by the end of the year.
NASA is also continuing to investigate the root causes of the aluminum silicate contamination inside the spacesuit's filtration system, and whether similar problems could affect other suits.
Suffredini said he had "high confidence" that operations will be back to normal by late July or early August, when the next series of NASA spacewalks is scheduled.
Concern about safety culture
Gerstenmaier said the investigation underlined the need for constant review of space safety standards. "When you start getting comfortable with the system, you've got to really keep digging," he said.
In a statement, NASA Administrator Charles Bolden said he was "especially concerned about cultural factors" that may have contributed to last year's spacesuit problems.
"In our exuberance to get the job done, we may have allowed ourselves to accept the commonly accepted causes for small anomalies," Bolden said. "We have a responsibility not to move on from any abnormal situation until we understand it fully or have suitable mitigations to prevent it happening again."
"We talked about this incident throughout all levels of the agency. ... I think it's a tribute to the agency that we're not hiding this stuff," Gerstenmaier said. "We're actually out trying to describe these things, describe where we can get better. I think that's how we prevent Columbias and Challengers."