From: Nick_Janow@mindlink.bc.ca (Nick Janow)
Newsgroups: sci.space
Subject: Re: Deep-sea Diving on Europa
Date: 18 Aug 92 02:02:30 GMT
Organization: MIND LINK! - British Columbia, Canada
Distribution: world

barrett@iastate.edu (Marc N Barrett) writes:
>  My question is: do we have any deep-sea diving equipment that could survive
> the great pressures that exploration of the bottoms of the Europan oceans
> would entail?

I've been helping develop a new science fiction role-playing game, and both
Europa and Ganymede are the sites of colonies, so I've been looking into the
possibilities for both worlds.  The figures I have for their ice and water
layers are:

Europa: 70km ice, 100km of water or slushy ice, then a silicate core of 1400km
radius, heated by radioactive decay and tidal friction (10% of Io's).

Ganymede: 100km ice, 400-800km water or slushy ice, then a silicate core of
1800-2200km radius.

Assuming that pressure is directly proportional to gravity, the bottom of
Europa's ice layer should have a pressure equivalent to Earth's ocean at around
10km.  We have vehicles that operate that deep in our ocean.  The bottom of
Europa's ocean might be equivalent to 25km of Earth's ocean.  Whether we can
manage to send a manned vehicle that deep is up to some creative engineers.  :)
Maybe a combination of scaling up present technology (thick-walled spheres) and
providing concentric layers of gradually decreasing pressure towards the
central manned chamber would manage it.  Then too, remote vehicles are easier
to design and have a longer possible duration, so they could handle much of the
exploration.

I was wondering how deep humans could feasibly handle free-swimming, with
artificial blood oxygenation.  I came across a comment about high pressures
distorting the shape of molecules, interfering with biochemical activity (the
proteins don't match up anymore), so there does appear to be a limit.

Europa (and many aspects also apply to Ganymede) should have had a deep ocean
for quite a while in its past, heated by radioactive decay, accretion heat,
tidal friction and heat radiated from Jupiter (I assume Jupiter radiated a lot
more in its earlier stages).  There would probably have been a greenhouse
effect due to evaporated water, methane and ammonia.  A nice warm, wet moon
with lots of geological activity might be suitable for starting life.

Life could have started there at underwater vents.  Photosynthesis might not
have developed, due to the low light levels.  Then again, maybe it was
efficient enough to compete with sulfide-reduction life, or whatever else there
might have been.

Another possibility is that Europa's life could have been based on radiation
from Jupiter's belt.  The radiation levels might have been high enough to
provide a significant energy resource, ripe for exploitation.  Perhaps the
radiation produces significant quantities of free radicals, without the help of
photosynthesis.  Unfortunately, this form of life would probably have died when
the thick ice layer formed.

Is there any way to exploit the other radiation from Jupiter (decimetric,
decametric, thermal)?  Maybe impurities along edges of ice formed antennas,
creating a weak electrical current, which powered a chemical reaction among the
organic impurities.  If the resulting chemicals improved the ability to extract
energy...evolution?  :)

Europa has lots of potential for speculation.  Was there life on Europa at one
time?  Is there life down there?  Are there physical processes in the core,
ocean and ice that fractionate elements to commercially-valuable levels?  Are
there "veins" of mineral-rich ice, formed by upwellings and slow freezing in
relatively low gravity?

...and of course the most important question of all: is Elvis there?  :-)

--

Nick_Janow@mindlink.bc.ca
Newsgroups: sci.space