On Apr 30, 11:09 am, Williamknowsbest wrote:
Atmosphere of Earth has a density of 1.26 kg per cubic meter. The
atmosphere of Venus, at an altitude of 55 km above the surface, is
mostly CO2 at Earth normal pressure and temperature, and its density
is around 3.75 kg per cubic meter. So, a plant that was genetically
engineered to form bubbles of oxygen inside them, would have a
bouyancy of about 2.49 kg per cubic meter. That is, if a plant formed
a ball say 1 meter in diameter and absorbed CO2 and sunlight on its
outer surface, and exhaled oxygen and water to its interior, it could
mass 1.3 kg spread across 3.1 sq meters of tissue area. That's 413
grams of tissue per cubic meter. With a density of 0.6 grams per ml,
that/s 690 ml per square meter. 0.69 mm tissue thickness.

To close the cycle, approximately 1/5th the mass should be animal
tissue. So, the plant tissue would be reduced to 0.85 mm and tiny
creatures ranging from mites to mice could be bred to inhabit the
interior and nibble only so far into the tissue layer, perhaps running
like rates in a exercise wheel, to bring fresh material to the bottom
of the sphere to eat it, and circulating the water and waste products
through the 'lawn' of the interior.

The plant - has a capacity to process sulfuric acid into sulfates
which are dropped from the balloon. Reproduction would an interesting
process - with perhaps tiny balloons fissioning off like dandelion
seeds. This favors mites rather than mice - which can ride on the
tiny balloons when the spawn. Mice sized infections of the interior
of offspring would require larger sized fissioning balloons.

The whole life process takes sulfur out of the air and turns it into a
solid - the same way certain life forms take calcium out of the ocean
and make solids out of it. The life forms also take carbon dioxide
out of the atmosphere and turn it into solids - plant material, and
animal tissue, and waste products which is mixed with sulfur and
dropped out of the system as more is added. Free oxygen also leaks
out of the system - so over time the atmosphere changes to Oxygen and
Water vapor -

While this is going on Fuller style cloud nine floating cities would
be possible. A 1 km diameter sphere carrying an oxygen argon
atmosphere would be 1 billion times as massive as a 1 m diameter
sphere so 1.3 million tons of material spread over 3.14 sq km of area
would allow 413 kg per sq meter. A sheet of glass 16.3 cm thick would
be possible with this system. A sheet of PET film (impervious to
sulfuric acid) could be 25 cm thick (10 inches!)

Clearly a multi-layer system of aluminum reinforced triangles imbedded
in PET film with a glassy interior layer would easily be made to
withstand the rigors of Venus, especially if deployed near the poles.
Since oxygen is lighter than carbon dioxide, a set of doosr at the
bottom of the sphere, form an airlock to admit aircraft and space
craft - just as a door in an underwater habitat remain open once the
pressures are equalized.

VTOL style propulsive skin aircraft/spacecraft similar to those used
on Earth, powered by lasers from space - which also power the spheres
- from an orbiting industrial ring - would easily navigate to these
cities and back. The cities themselves are made from asteroidal
feedstock on orbit and deorbited collapsed and then opened after
they've slowed to subsonic speeds. At 50 tons per person, each
sphere carries up to 65,000 people and nominally carries 50,000 people

The city, like the plant systems, drop sulfur and carbon solids from
them, while releasing oxygen and water vapor into the atmosphere.

Molecular sieves and pumps maintain oxygen atmosphere. A simple
system of electrolysis driven by laser is used to take sulfuric acide
and reduce it to hydrogen and oxygen and sulfur dioxide. Another
laser driven system involves iron catalysts and carbon to break oxygen
from CO2 using laser power from space.

H2SO4 --- SO2 + H2O + 1/2O2
CO2 --- C + O2

Carbon and sulfur can be combined into a wide range of compounds that
when dropped to the lower atmosphere would cycle up more CO2 and more
H2SO4 to convert into water and oxygen.

http://en.wikipedia.org/wiki/Organosulfur_compounds

Some of this could be engineered into the mice and plants mentioned
earlier.

Given the mass of the Venusian atmosphere, the mass of materials
needed to be processed, the efficiency of the processes used, and the
energy available to process them - we can estimate the time frame for
full conversion of the Venusian atmosphere to water and oxygen.

Given the amount of argon in the atmosphere, I wonder what happened to
the nitrogen? It likely reacted with the rocks below and released
the sulfur that we see. If the temperature drops - and chemistry
changes - enforcing a planetary cooling on Venus by lowering CO2
levels - we may find that when the surface conditions start to change,
nitrogen levels rise, and sulfur gets sucked up leaving carbon and
water on the surface. At that point the plants and animals and cities
have descended to the surface and operate freely there.

Not that your plan of action as based upon working from the cozy and
buoyant 50 km altitude on down isn't technically doable, because it
most certainly is.

However, since equalized pressure is not a negative/insurmountable
biological issue, and If technologically situated upon that
geothermally forced surface as is (though obviously not in the buff),
and were given unlimited local energy (fully renewable none the less),
what couldn't be resolved on behalf of human habitats?
.. - Brad Guth