Teraforming Venus - again....


Why not put a layer of utility fog at 50km? It could rotate once every 24=
=20
hours and provide an environment that is nearly identical to Earth.

From http://en.wikipedia.org/wiki/Colonization_of_Venus

------ begin quote
Aerostat habitats and floating cities

Geoffrey A. Landis has summarized the perceived difficulties in colonizin=
g=20
Venus as being merely from the assumption that a colony would need to be=20
based on the surface of a planet:

"However, viewed in a different way, the problem with Venus is merely=
=20
that the ground level is too far below the one atmosphere level. At=20
cloud-top level, Venus is the paradise planet."

He has proposed aerostat habitats followed by floating cities, based on t=
he=20
concept that breathable air (21:79 Oxygen-Nitrogen mixture) is a lifting =
gas=20
in the dense Venusian atmosphere, with over 60% of the lifting power that=
=20
helium has on Earth.[2] In effect, a balloon full of human-breathable air=
=20
would sustain itself and extra weight (such as a colony) in midair. At an=
=20
altitude of 50 km above Venusian surface, the environment is the most=20
Earth-like in the solar system - a pressure of approximately 1 bar and=20
temperatures in the 0=B0C-50=B0C range. Because there is not a significan=
t=20
pressure difference between the inside and the outside of the breathable-=
air=20
balloon, any rips or tears would cause gases to diffuse at normal=20
atmospheric mixing rates, giving time to repair any such damages. In=20
addition, humans would not require pressurized suits when outside, merely=
=20
air to breathe and a protection from the acidic rain. Alternatively two-p=
art=20
domes could contain a lifting gas like hydrogen or helium (extractable fr=
om=20
the atmosphere) to allow a higher mass density.[3]

Cloud-top colonization also offers a way to avoid the issue of slow Venus=
ian=20
rotation. At the top of the clouds the wind speed on Venus reaches up to =
95=20
m/s, circling the planet approximately every four Earth days in a phenome=
non=20
known as "super-rotation".[4] Colonies floating in this region could=20
therefore have a much shorter day length by remaining untethered to the=20
ground and moving with the atmosphere. While a space elevator extending t=
o=20
the surface of Venus is impractical due to the slow rotation, constructin=
g a=20
skyhook that extended into the upper atmosphere and rotated at the wind=20
speed would not be difficult compared to constructing a space elevator on=
=20
Earth.

Since such colonies would be viable in current Venusian conditions, this=20
allows a dynamic approach to colonization instead of requiring extensive=20
terraforming measures in advance. The main challenge would be using a=20
substance resistant to sulfuric acid to serve as the structure's outer=20
layer; ceramics or metal sulfates could possibly serve in this role.

Landis has suggested that as more floating cities were built, they could=20
form a solar shield around the planet, and could simultaneously be used t=
o=20
process the atmosphere into a more desirable form. If made from carbon=20
nanotubes (recently fabricated into sheet form) or graphene (a sheet-like=
=20
carbon allotrope), the major structural materials can be produced using=20
carbon dioxide gathered in situ from the atmosphere. The recently=20
synthesised amorphous carbonia might prove a useful structural material i=
f=20
it can be quenched to STP conditions, perhaps in a mixture with regular=20
silica glass. According to Birch's analysis such colonies and materials=20
would provide an immediate economic return from colonizing Venus, funding=
=20
further terraforming efforts.

Landis' point about the ground level being too far below the one atmosphe=
re=20
level was also used by Larry Niven in his depiction of Plateau, a Venus-l=
ike=20
planet with a small section of its surface rising up to the habitable lev=
el=20
of the atmosphere. Similar setting is used in one of the early Poul Ander=
son=20
novels.
--- end quote
=20

.

Relevant Pages

  • Recreating Venus In The Lab
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  • Terraforming Venus - again
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  • The unexpected temperature profile of Venuss atmosphere (Forwarded)
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