NASA has a reputation for leaving no stone unturned to correct anything that goes wrong. True to form, it launched an exhaustive investigation after a leak sprung in a spacesuit during a spacewalk last summer, putting the astronaut in peril of drowning in his helmet. The report (pdf) was released on Wednesday; it includes 49 recommendations for changes to implement at NASA to make sure it never happens again.
Italian astronaut Luca Parmitano was 44 minutes into a spacewalk outside the International Space Station on July 16 when he reported that water was floating around in his helmet. The problem quickly worsened, and NASA called the spacewalk short, sending Parmitano and his partner Chris Cassidy of NASA scrambling to get back inside the station. While Parmitano was making his way, the water moved from the back of his head to the front, clogging his nose, blinding his vision and intermittently cutting his radio communications. By the time he removed his helmet inside the station, 1.5 liters of liquid had accumulated. "Of all the EVA [extravehicular activity] issues that we've encountered to date, this is probably the most serious," NASA International Space Station Program Manager Mike Suffredini told reporters during a teleconference on Wednesday.
NASA immediately launched an in-depth investigation into the accident, appointing a group of experts outside of the normal space station team to find out what went wrong, both in terms of the hardware and the space agency practices that let this happen. "We decided it would be in the best interests of NASA to have an independent group go look at this," said William Gerstenmaier, associate administrator for NASA's Human Exploration and Operations Mission Directorate. "This was a high-visibility enough event that I think it warrants a broader look, not only from an anomaly perspective but from an overall agency perspective."
One of the surprising findings of the report was that July 16 was not the first time this leak had appeared. During another spacewalk just a week earlier a small leak was noticed, but was attributed to a much more minor problem of a malfunctioning drink bag. "This event was not properly investigated, which could have prevented placing a crew member at risk a week later," the report stated.
In fact, both leaks were caused by a blockage in the spacesuit's water separator that allowed liquid to leak into a vent loop and into the helmet. That the spacesuit could fail in this way had never been anticipated, in part because the flow of water in microgravity caused these components to work differently than they did during ground tests. "When you combine the behavior of water and how it works in zero gravity, and when you combine that with a very complex system…it's impossible to test on the ground," said Chris Hansen, an ISS chief engineer and chair of the Mishap Investigation Board. "It's just a really difficult thing."
Still, the report concluded that mission controllers should have dug deeper into the earlier leak and should have recognized the seriousness of the problem sooner. Some of the report's recommendations are aimed at getting engineers to be more open-minded when analyzing failures. "What this tells us is that we need to always be vigilant," Suffredini said. "The suit has been around for 35 years, we have quite a bit of experience. But even in systems we think we know, there's always an opportunity for us to ask the next question and think twice about something that we think we understand."
The investigation team also recommended the agency should  make it easier for space station staffers to raise problems and request astronaut crew time to address them, even if that takes away from the crew's valuable hours devoted to science experiments. The report also requests improved communication channels between the Space Station Program Office and the  office responsible for EVAs at the NASA Johnson Space Center in Houston to enable quicker decision-making when problems arise.
NASA has already implemented many of the report's recommendations, and officials hope to have all of the critical ones done by June, to be ready to schedule the next EVAs in July or August. "I look at this as a chance that we can all improve and do better," Gerstenmaier said. "We're going to learn from this event and make sure we do better in the future."