Low-Profile Breathing Device for Improved Pre-breathe Procedures

Jesse performing a fit checkNitrogen and oxygen are the two primary components of the air we breathe. Oxygen is readily used by the body, whereas we don't use much nitrogen.  Some nitrogen is absorbed into our tissues and blood with most of it being simply expelled from the body when we exhale.

Another view of fit checkUnder increased pressure, such as that experienced by divers, more air is forced into the body, including more nitrogen. Then, as the pressure decreases, that additional nitrogen must be exhaled. But if the pressure decreases rapidly, rather than being released from the blood in the lungs as a gas that can be exhaled, the nitrogen forms bubbles in the bloodstream.  These bubbles cannot be exhaled but rather travel through the body/bloodstream, where they can block blood vessels, press on nerves and expand in muscle tissue creating serious problems.

Michelle taking notesThis scenario has been referred to as Decompression Sickness or "The Bends."  The symptoms of the bends, so-called because of the body's response to the severe pain the bubbles can cause, vary from itching and swelling to difficulty breathing and muscle weakness to total paralysis, coma and even death.

In the space shuttle, the pressure in a space suit is lower than the pressure in the cabin and the pressure outside the craft is almost non-existent. Hence, an astronaut faces the same risk of decompression illness that a deep-sea diver does.

CAD drawing of snorkelThe solution for astronauts is to exercise vigorously for about three hours, breathing pure oxygen, to eliminate as much nitrogen as possible from the body prior to getting into the space suit. But the space suit is a tight fit, and the astronauts can't keep the oxygen mask on and get into the suit. They have to hold their breath while they finish putting on the suit and switch to the suit's oxygen.  If they forget and breathe in cabin air, they have to sit in the suit and breathe from the oxygen mask for one-half hour before they can work outside the shuttle or they risk getting the bends.

Early SLA model - Manufactured courtesy of Hamilton SundstrandThe solution, as envisioned by Dr. John Graf of NASA's Johnson Space Center, is a smaller oxygen mask, a snorkel, one that the astronaut can keep using until the helmet to the suit is sealed, at which point the mask can simply be dropped away into the suit. Students in the College of Technology have developed such a snorkel and are testing it in conjunction with NASA personnel.

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