originally posted by: Zaphod58
a reply to: Bedlam
I haven't heard everything they've done, but judging by the condition of some of the pilots after flying, they SHOULD have.
I'm not in those loops. If any of the guys in your extended contact group know, I'd be interested.
We had a few big issues with..um..self contained environment air, let's say, that caused non-stop problems. It's a different thing with an OBOGS setup
but still, I'm wondering if there's a similar fix, especially considering they're probably using bleed air as a feed stock.
Navy contrives to fix some of these on subs by essentially 'incinerating' the air and then filtering the residue, that SORT of works, but causes other
issues with the residue. For both space systems and the sub fleet, a lot of residual problems were solved by catalytically breaking VOCs, CO, and
higher order oxygen allotropes. There was another issue with nitrogen oxides of various types, another catalyst stage for that, the whole thing ended
up fairly compact although you need power and some heat sinking - one stage needs UV and another works better hot than room temperature. It was
contrived to use the waste heat from the UV generator to provide some of the heat for the other stage but you still have to keep the temperature
fairly stable for optimal function.
eta: the issues fixed included CO poisoning, you can spot that with a carboxyhemoglobin test, but oddly enough you need to do the draw RIGHT THEN or
it'll look normal after - if you're in an environment where they're keeping the pressure low but the O2 level high to reduce nitrogen saturation
issues, you'll see oxygen deprivation looking symptoms that resolve unusually quickly and don't leave a trace. Most medics think the CO will hang
around because at STP it does, but the carboxyhemoglobin in space systems can leave the bloodstream faster than you expect because the environment
ISN'T STP when you're breathing O2 mix and juggling the pressures up and down.
VOCs, nitrogen oxides and higher order oxygen allotropes can cause temporary alveolar changes that reduce gas exchange either by edema or by altering
membrane chemistry, and they, too, can resolve faster than you'd expect although they tend to last longer. It's also mission duration dependent.
Are they seeing problems with wound healing with people on OBOGS systems using bleed air yet? That'll be an issue. The longer the flight, the worse
etaa: did they change the mask or hose design just before the issues started?
edit on 5-4-2017 by Bedlam because: (no reason given)