Re: SETI and The Fermi Paradox

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.

<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.

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.

http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA956126
 �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. 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. 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.�

 ~ BG