Putting a snorkel on a space suit seems about as daft as making water wings for a meerkat, but that’s exactly what NASA has done. It isn’t some bureaucratic error, but a serious piece of life-saving engineering inspired by an incident in July, when an astronaut on the International Space Station (ISS) almost drowned in his own helmet when water started leaking in. Now faced with urgent repairs due to a faulty cooling system, NASA has come up with a quick fix, so a team can venture outside the station in safety while the cause of the leak remains under investigation.
On July 16, during a spacewalk outside the ISS, Flight Engineer Luca Parmitano, an ESA astronaut from Italy, thought he was getting a bit sweaty. Suddenly, he felt something like a giant, sweaty amoeba crawling over his head and ears. Water was leaking into his helmet and clinging to his head in zero gravity, making it impossible to hear or be heard over his radio headset. American astronaut Christopher Cassidy realized what was happening and was able to lead Parmitano back to an airlock before the water could cover his nose and mouth.
The question is, where did the water come from? That turns out to be harder to answer than you might think. The Extravehicular Mobility Unit (EMU), as the NASA space suits used on the ISS are rather blandly called, isn’t just an inflatable set of coveralls and, Sandra Bullock notwithstanding, you can’t slip one on and off in 30 seconds.
The EMU is actually a miniature spaceship complete with rockets for moving about. It has a complete life support system to keep an astronaut alive and relatively comfortable for eight hours, but that means a lot of surprisingly sophisticated technology in a package more complicated than anything you’d get kitted out with in Bond Street.
A key component of the EMU is the Liquid Cooling and Ventilation Garment (LCVG), which is basically a set of long johns with plastic piping stitched into them. Through the tiny pipes run cold water, which keeps the astronaut cool. That’s because, for all the talk about how hot or cold space is, it’s really more like being stuck inside a thermos flask. Normally, the air around a person’s body draws away heat by convection, but in a vacuum there’s no where for it to go, so the wearer is slowly poached in his own sweat.
The LCVG transports cold water from the suit’s backpack to the astronaut and it provides ventilation to carry away the sweat. To keep the wearer from becoming dehydrated, the suit also has a water bag from which to drink. One possibility is that the water in Parmitano’s helmet came from the LCVG, and another is that it’s from the water bag.
The tricky bit is that it’s hard to get either to leak on cue, and since the LCVG uses a series of parallel pipes to prevent cold spots on the suit, there are a lot of potential leak points that haven’t been chased down yet. Back in August, NASA and the crew of the ISS managed to recreate the leak, but the cause still isn’t clear. One possibility is that the water in one or both suits may have been contaminated on filling due to a faulty filter, resulting in a blockage.
That’s where the snorkel comes in. Made from a length of spare plastic tubing with the end smoothed down and wrapped in Velcro to keep it in place, its purpose is to provide the astronaut with a clear breathing path if the fault reoccurs and water leaks in again. In addition, the astronauts have installed absorbent pads, a bit like those in a diaper, in the back of their helmets that will absorb any water that floats in. The astronauts have been trained to sense when the pad becomes “squishy” due to excess moisture.
The reason behind this lash up is a trio of spacewalks that NASA has scheduled for next week, when American astronauts Mike Hopkin and Rick Mastracchio will attempt to replace a faulty pump module in one of the station’s cooling systems.
The video below explains the spacewalk and the suit modifications.
Source: NASA
