In article <6af10a2c-6fda-4cac-ba39-138a050f8...@i4g2000prm.googlegroups.com>,
BradGuth <bradg...@gmail.com> wrote:
On Sep 20, 10:16 am, Morten Reistad <fi...@last.name> wrote:
In article <h946hk$mf...@news.eternal-september.org>,
Nightcrawler <Dirtyde...@dirtcheap.net> wrote:
The only way to work under that kind of pressure is saturation, or containment, as in a
submarine type vehicle.
Prolonged saturation is out.
Humans seem evolutionarily locked into a habitat of ppO2 between 0.15 and 0.45,
with brief excursions to 0.12 .. 1.6 possible. We also need a ppN2 of around 0.4 to
2.0 for longer term exposures. We can tolerate absolute pressures from around 0.3
to 10 bar with the balance being Helium, or possibly Hydrogen. Hydrogen may, or
may not, substitute for Nitrogen. We still don't know. You see, none of the pioneers
survived, so they closed the reserach down.
All excustions to higher pressures depend on balancing HPNS with Nitrogen, and
in extreme cases Hydrogen. That is a thin edge, and you need to compensate
for bursts of activity almost before they happen. CO2 ventilation becomes a
huge problem.
As LAB animals we can be pressurised to close to 70 athmospheres, but that
requires detailed plans of physical activity and a closed laboratory environment.
The process became so complex and the He-N and O2-CO2 balances so brittle that
they called it a day.
<snip>
Maximum record depth is 2000 feet in an "ADS" suit.
They have been deeper, but the suit depends on steel with
copper o-rings.
Maximum recorded depth with SCUBA is 1083 feet.
for a bottom time of around 10 minutes.
I have read the accounts and seen the videos from 4 of the
survivors of such dives. And seen the videos and read the
inquests from three of the non-survivors. Most of these are
well worth the trouble. We, mortals, can actually learn something
from them.
ADS suits are practical (on Earth), SCUBA is not.
The deepest saturation dive done was a simulated one to
almost 2000 ft, 600 meters. It was not repeated because
of staggering cost. 2 months of decompression.
However, nothing will work on Venus. The ADS suit is
rugged but is not designed for chemical or heat resistance.
The denaturing of the proteins in the human body is an extreme
risk. There is no practical way to support the suit (currently
operates like a tethered submersible).
SCUBA will be fatal instantly.
Now that there are occupational hazard rules for saturation
diving we can use those as a reference. Maximum tolerance for
permanent habitat pressures is 10 atm, with brief excursions
to 18 atm. (90, 170 meters). Max partial pressure for oxygen
is 0.4, max partial pressure for Nitrogen and Argon combined
is 3.2, 2.0 when performing work. So, the remaining 7.5
athmospheres is Helium. Which has a whoe ballpark of problems.
We only have three materials we have knowledge of for such
high pressure use. Steel, Aluminium 6xxx series and kevlar
epoxies. All of these corrode within seconds on Venus.
In fact, anything sent there dies. Machine or biological.
The subject is a stupid "what if", anyway. Sort of like the crap you
would hear from a 6 year old.
Indeed. The closest to realism observer craft would be
a dirigible, not exposed to 90 bar, but only to 3-4.
But it would be "plankton", unmanouverable for all
practical purposes. But it could tell us a lot about
Venus by remote sensing.
-- mrr
Your continued inability to research is noted, as is your inability to
deductively think inside or much less outside of that cozy mainstream
box of yours.
So you come bringing only insults. Prehaps you could make some
suggestions to materials we could use, with some actual factual
basis? The Oil, Aerospace, Mining and Shipping industries would
shower you with money if they could have something that did not
explosively corrode in oxygen fires and can withstand 600 bar or
more. They need this right now, to build stuff that can bring in
trillions. Like Shtockman.
http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identi...
“Abstract : Simulated dives were made with dogs to a depth equivalent
to 1000 feet of Sea water (305 meters). Sixteen of these animals
breathed a non-explosive hydrogen-oxygen mixture (hydrox) containing
no more than 3% oxygen, while 12 breathed gas mixtures containing
helium in place of hydrogen.
Let us see, that is less than half of the Comex record. 1/3rd vs
2/3rds of the way to Venus surface. 620msw. Venus is 930msw.
3% oxygen at 31 athmospheres is a ppO2 of around 1.0. This is
not sustainable for more than one day. You see, we have very good
numbers for this, from countless patients and divers. At above
0.45 bar in ppO2 you must count OTUs. ppO2 of 1.0 give you 1440
minutes.
This is a death zone, just like on Everest.
You only need to breathe every 3 minutes at these 600msw, but that
task is a large strain. A sheet of paper takes more than a minute
to get from hand to floor, even in hydrogen. At around 820 msw Helium
has the same viscosity as water at the surface. OK, Hydrogen is still
lighter, but not very much.
And CO2 can come out and hit you, any time. We have a body that
makes unpredictable CO2 spikes. How many CO2 hits have YOU
experienced? Did you lose conciousness in any of them?
In a number of dives, animals were
exposed to hydrogen continuously for between 96-100 hours, 48 of which
was spent at 1000 FSW. Extensive pre- and post-dive blood enzyme and
hematological studies were carried out. In addition lung, brain and
liver biopsies were carried out on selected animals. all such studies
showed no significant abnormalities. One dive employing helium and one
dive employing hydrogen proved fatal. In both instances, these
fatalities were due to volatile hydrocarbons present in a cylinder of
contaminated oxygen.
Yes, even the navy makes oxygen fires, even on multiple digit billion
dollar projects. apollo-1, Apollo-13 and the first space shuttle
blowup were oxygen fires. They are an intrinsic hazard, made
exponentially bigger by using/mixing Hydrox.
All other animals survived the exposures. Indeed,
some animals made more than one dive. Three of these animals still
appear normal after 3 to 5 years post-dive. EEG studies showed no
residual post-dive abnormalities and no evidence of High Pressure
Nervous Syndrome while at 1000 FSW, although transient EEG
abnormalities were noted during hypoxia. Techniques were developed for
mixing hydrogen and oxygen in a non-explosive manner. The techniques
developed for the use of hydrox appear to be reasonably safe. For the
past eleven years, this laboratory has carried out over 645O hours of
hydrox exposure on animals including mice, rats, dogs, and man, and
has mixed approximately 200 cylinders of hydrox without an accident
related to the use of hydrogen.”
Perhaps you can relay some facts of how many hours (continous) of
Hydrox exposure with a ppH of above 10.0, (in the death zone) has
been logged?
That is where the problem lies.
-- mrr
Who haven't visited that death zone, but have been reasonably close
to it. Close enough to feel the CO2 overwhelm the body.