Re: Zero Gee Entry Seat
- From: Craig Fink <WeBeGood@xxxxxxxxx>
- Date: Wed, 11 Jan 2006 13:00:27 GMT
On Sun, 08 Jan 2006 20:17:00 -0500, John Perry wrote:
> William Mook wrote:
>>
>> Once of the problems with very high gee forces too is that you've got
>> to build your spacecraft really well to withstand them. So, weight is
>> a factor in the structure to carry out these high gee maneuvers. Also,
>> what are the operational advantages of high gee maneuvers? You can get
>> where you're going quickly. But, by clever design you can use lots
>> less energy and operate at far lower gees... and that pays dividends
>> in crew comfort, structure loads, and hence weights, and no need for
>> things like big tanks of neutrally bouyant liquid
>
> All quite true, but...
>
> (it won't be water
>> since water is too dense!)
>>
>>
> Actually, water is a bit less dense than the human body. The only
> reason we float is that we have lungs and stomach that are filled with
> air, which overcomes the body's tendency to sink, especially in fresh
> water.
>
> The real problem stems from these air-filled cavities -- in very high g
> situations, the surrounding fluid pressure will crush the rib cage and
> lungs. This is discussed in, e. g.,
>
> http://www.luf.org/wiki/view/TMP/BifrostBridge?rev=1.2.
>
> The solution to that is the same as for all high-pressure environments:
> fill the lungs with an oxygenated fluid. As far as I've been able to
> find, this is still a research project, even for high-pressure
> environments, and is still little more than speculation for high-g
> regimes.
>
> I'm sure some of the more knowledgable can amplify and correct my
> comments.
>
Reading the article two problems still seem to be present, chest pain and
optic problems. Not really a crushing of the rib cage, but the heart is
still essentially in air. Also, it sounds like the optic nerve is getting
stretched as the brain settles into the back of the skull. Supporting the
brain with the optic nerves.
Yeah, I agree, filling the lungs with a fluid, like that used in extremely
deep diving might fix the cardiac problems. So the the heart, arteries and
veins are supported by the fluid filled lungs.
The problem with the optic nerve could be fixed with a change in
orientation. Face down in the fluid instead of face up. I would think this
would compress the optic nerve instead of stretching it.
Lets see, the more knowledgeable people would have been in their prime in
the 1940's, 50's and early 60's. That makes them pretty old right now.
That is, unless there are unpublished studies that were performed in the
interim. Any more recent studies out there?
http://www.luf.org/wiki/view/TMP/BifrostBridge?rev=1.2.
<begin quote>
The increase in tolerable Gs in humans by total liquid immersion gave only
an experimentally determined increase of a factor of 2 at G magnitudes
below 10 Gs
<end quote>
I still think at low to moderate gee's, fluid immersion would
significantly reduce stress on sick, injured or elderly astronauts. Even
without supporting the heart in fluid, it reduces the hydrostatic pressure
problems throughout the rest of the body. From the article, sounds like
the stress reduction might be around 50%.
--
Craig Fink
Courtesy E-Mail Welcome @ WeBeGood@xxxxxxxxx
.
- References:
- Zero Gee Entry Seat
- From: Craig Fink
- Re: Zero Gee Entry Seat
- From: William Mook
- Re: Zero Gee Entry Seat
- From: John Perry
- Zero Gee Entry Seat
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