NASA issue sobering EMU water leak investigation update
The investigation report into Luca Parmitano’s eventful spacewalk last year provided some sobering reminders of the need to be vigilant in the face of any and all minor issues in space, before they escalate into an emergency. Findings released on Wednesday revealed the dangerous water leak in the Italian’s helmet could have been avoided, had the teams on the ground correctly diagnosed a problem with the suit during the previous EVA.
Parmitano is now safely back on Earth following his tour on the International Space Station. His expedition duties included his first two EVAs on the outside of the Station.
It was the second of his spacewalks that became the center of the EMU investigation, following the early termination of EVA-23 on July 16, 2013.
The problem related to water leaking and building up in his helmet, around one hour into the planned six hour spacewalk.
Despite the issue being extremely serious, Luca’s life was never in immediate danger – mainly thanks to his own, his EVA partner Chris Cassidy, the ISS and ground control team’s professionalism, as they put into work their extensive training by safely returning the Italian into the safe haven of the Quest Airlock.
Technically, the investigation into what went wrong with Luca’s suit began moments after he egressed the airlock and removed his helmet.
However, as per NASA’s tried and trusted methodology in solving problems in space, it was the task of experts on the ground to nail down the root cause.
That investigation was conducted by NASA’s Anomaly Resolution Team (ART) at the Johnson Space Center (JSC) in Houston, in tandem with hands on evaluations into the suit – known as EMU 3011 – by the ISS crewmembers.
The EMU is a highly complex life support apparatus that has proved to be highly reliable during its role of providing safety to astronauts working on the outside of spacecraft.
As such, pinpointing the problem with EMU 3011 was never going to be a speedy process.
Per the ART investigation (full coverage in L2), the initial theory pointed towards a vent loop water leak caused by either a blocked or clogged Water Separator Tube, a blocked condensate water relief valve, or a blocked condensate water line – causing the water separator loop to allow excessive amounts of water to enter the ventilation loop.
Testing the suit, involving the replacement of hardware elements along the root cause path, gained mixed results, while a plan to send additional hardware uphill and back to Earth was aided by the Station’s continually busy Visiting Vehicle schedule of both Agency and commercial resupply ships.
A breakthrough was found when the Fan Pump Separator was examined after returning to Earth on a Russian Soyuz.
Engineers found aluminum silicate contamination clogging a line in the system, a blockage that had caused water to back up into Luca’s helmet.
It is not currently known how the contamination found its way into the system, which in turn means the root cause is still being evaluated.
In revealing their results, the Mishap Investigation Board (MIB) also noted water had leaked into Luca’s helmet during his first EVA a week previous.
However, the team on the ground assumed the liquid originated from a fault in his water drink bag – a problem that was thought to be the cause of the more serious leak during conversations with the spacewalker, as the teams discussed the buildup of liquid around Luca’s head during the second EVA.
The MIB pulled no punches in criticizing the original misdiagnosis, not least because the teams could have avoided the more serious problem during the second EVA – by delaying the second spacewalk in order to further investigate Luca’s EMU suit problems.
Several choice words were used to portray the failure to correctly investigate the issue, including schedule pressure and complacency, words often associated with the major disasters suffered by NASA over its history.
“While I am concerned about ensuring this particular incident does not happen again, I am especially concerned about cultural factors that may have contributed to the event,” wrote NASA administrator Charlie Bolden in response to the investigation.
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“As the person ultimately responsible for all we do as the NASA family, I implore you to welcome risks, because that is how we push the boundaries of our achievement, but at the same time, I must emphasize in the strongest terms that we must not be complacent in our quest to ensure the safety of our crew members and teams on the ground.”
Thankfully, no disaster occurred during the professional termination of the EVA – as much as the MIB intimated there was a longer-than-required delay to ending the spacewalk.
Parmitano’s calm approach to the deteriorating situation, along with his work site being in close proximity to the Quest Airlock, avoided an emergency re-press scenario – as much as it was expedited – after he was aided back into the safety of the ISS by his fellow spacewalker Chris Cassidy.
The MIB – which also found issues with the ground testing of how a collection of water inside the system behaves when interacting with the fan/pump module – made numerous recommendations for implementation, some of which are already now in effect.
Once all the recommendations have been adhered to, a return to nominal EVA operation for US spacewalks outside of the ISS should be provided with a green light. Contingency EVAs – such as the EVAs over Christmas to replace a faulty Pump Module – will be discussed and approved if and when they are required.
Allowance for a full compliment of working EMUs on Station will be aided by a space relay of two suits – EMU 3003 up and EMU 3015 down – during SpaceX’s CRS-3/SpX-3 Dragon mission next month. Luca’s EMU 3011 had already returned to service, following the replacement of the affected hardware.
(Images via NASA and L2).