Pure O2 effects in spaceflight

[Noboundaries]

Gilldiver, thanks for that input. I flew Navy jets for over ten years, sucking 100% O2 the entire time, and body gas composition was never discussed, not once. We were basically told you'd pass out from oxygen starvation if you went off O2 for very long at altitude. I can't remember a single time anyone discussing decompression sickness, but it makes complete sense.

I personally had several incidents when I lost cabin pressure at altitude (35 to 40,000 feet). When that happens in Navy jets, a positive pressure system kicks in forcing the O2 into your lungs. Made communications very interesting and strained, but decompression sickness wasn't part of the equation.

Thanks for the missing piece of that puzzle.

 

[D_B]

One main reason for low pressure in the EVA suits is suit joint mobility
... interesting thread , thanks

 

[Gilldiver]

One main reason for low pressure in the EVA suits is suit joint mobility
... interesting thread , thanks

That is a very big problem. The other is suit inflation - think of the guy in a dry suit that blows it up to look like the Michelin Man and you get the idea.

What I have been told is that the most difficult things is the gloves which have to be hand tailored to each individual.

It is also why I think that Oceanengineering was awarded the contract for the design of the next generation suits. I think NASA wanted a more universal suit that could be run at a higher ATM. The hard diving suits might make a good model for that.

I know my buddies at Hamilton Sundstrand were just about as pissed loosing that contract as my company, Sikorsky, was loosing the contract for the Presidential helicopter to the Italians.

But, I read that the suit contract had been pulled back, so Hamilton may get another shot at it.

 

[Thalassamania]

New suit designs may be "hardsuits" like a lightweight version of the Newt Suit.

 

[Dr Deco]

Hello Readers:

There is considerable interest in this subject. From the ORBITER CABIN to the EMU is equivalent to going to the top of Mt Everest starting from sea level. [The original posting of September 17th was filled with typos. Ouch! It had more errors than an early Mets game. ]


Altitude DCS

Decompression to altitude is indeed an old question. In 1917, Yandell Henderson wrote, “In the present state of the art of flying, it is scarcely possible for an aviator to rise to the height of 20,000 feet….in a period sufficient brief to allow bubbles..to form.” (1) The performance of aircraft quickly improved and it did present itself as a serious problem.

During WW II, considerable work was performed by several research groups to alleviate the consequences reduced pressure during high altitude bombing missions. It never developed into an operation problem, though. Ferris and Engle wrote, “…the altitudes attained in sustained combat flights …were below the critical attitudes at which severe decompression sickness is common.” (2)

NASA Studies

My research at NASA was primarily directed towards to objectives.

[a] Why was the incidence of DCS much lower in space than in similar depressurizations conducted at ground level, and
how do you maximize the effectiveness of oxygen prebreathe with respect to time and consumption of oxygen?

Dr Deco :doctor:

The next class in Decompression Physiology for 2008 is November 15 - 16.
This class is at the USC campus in Los Angeles.
link: Advanced Decompression Physiology Seminar Information


References

1. Henderson, Y. Effects of altitude on the aviator. Aviation, 1917.

2. Ferris and Engle, Chapter II in: Decompression Sickness, 1951. J.F. Fulton, ed.