Hugh Pickens DOT Com writes "About 44 minutes into a 6.5-hour spacewalk last July, Italian astronaut Luca Parmitano noted that water was building up inside his helmet – the second consecutive spacewalk during which he reported the problem. As Parmitano worked his way back to the air lock, water covered his eyes, filled his ears, disrupted communications, and eventually began to enter his nose, making it difficult for him to breathe. 'I know that if the water does overwhelm me I can always open the helmet,' wrote Parmitano about making it to the airlock. 'I'll probably lose consciousness, but in any case that would be better than drowning inside the helmet.' Later, when crew mates removed his helmet, they found that it contained at least 1.5 quarts of water. In a 122-page report released Wednesday, a mishap investigation board identified a range of causes for the near-tragedy, including organizational causes that carried echoes of accident reports that followed the loss of the shuttles Challenger and Columbia and their crews in 1986 and 2003. Engineers traced the leak to a fan-and-pump assembly that is part of a system that extracts moisture from the air inside the suit and returns it to the suit's water-based cooling system. Contaminants clogged holes that would have carried the water to the cooling system after it was extracted from the air. The water backed up and flowed into the suit's air-circulation system, which sent it into Parmitano's helmet (PDF).
The specific cause of the contamination is still under investigation but investigators also identified deeper causes, one of which involved what some accident-investigation specialists have dubbed the 'normalization of deviance' – small malfunctions that appear so often that eventually they are accepted as normal. In this case, small water leaks had been observed in space-suit helmets for years, despite the knowledge that the water could form a film on the inside of a helmet, fogging the visor or reacting with antifogging chemicals on the visor in ways that irritate eyes. NASA officials are not planning on resuming non-urgent spacewalks before addressing all 16 of the highest priority suggestions from the Mishap Investigation Board. 'I think it's a tribute to the agency that we're not hiding this stuff, that we're actually out trying to describe these things, and to describe where we can get better,' says William Gerstenmaier, associate administrator for NASA's Human Exploration and Operations Mission Directorate. 'I think that's how we prevent Columbias and Challengers.'"