A research team at the Duke University Hyperbaric Centre, (North Carolina, USA) has won a Johnson Space Center (JSC) Group Achievement Award from NASA. The Durham based team comprising Dr Neal Pollock, Dr. Richard Vann, Mike Natoli and Dr Richard Moon. Dr Neal W. Pollock and Dr Richard D. Vann developed an in-suit light exercise pre-breathe regime to prevent decompression sickness developing in astronauts.
Although it might not seem immediately obvious, there is a strong link between astronauts, rebreathers, diving physiology and physics. A space suit is effectively an oxygen rebreather with the contents of the suit recirculated through a CO2 scubber. However the helmet doesn’t suffer the same CO2 retention problems that some diving helmets can, mainly because the gas is far less dense, therefore it circulates easily around the system.
“When an astronaut transitions from Space Station pressure (1 bar) and dons a space suit (0.29 bar), the pressure on them drops by 0.71 bar”, stated Neal Pollock. “It’s the same effect as instantly going from ground level to a thousand feet above Everest. Consequently one of the dangers of space walking is that decompression sickness will result if there is no intervention or treatment. Although the astronaut hasn’t been diving, he does have nitrogen in his tissues - in equilibrium with the content at ground level pressure. With an immediate drop in pressure the gas comes out of solution forming bubbles and possibly symptoms of decompression sickness, just like diver experience. We needed to wash out nitrogen from the astronauts’ tissues by having them breathe pure oxygen; an old trick used since World War II by bomber and fighter crew."
The full story can be found here, see page 6 of X-Ray Magazine, May Issue, # 48
Dr Neal W Pollock and Dr Richard V Vann also work at DAN Headquarters in Durham, respectively as Research Director and Consultant. They are two members of the team behind Rebreather Forum 3.