Terraforming Venus

[JoeP]

Hey, those floating cities of Venus is a neat idea.

Still, I don't get the advantages. OK, you get some radiation protection due to the atmosphere, and you can plenty of gas products to make O2 and maybe some other things.

But you are essentially immersed in a hostile place, and if you fall, you die.

Orbital cities around Earth sounds more friendly, IMO.

Smashing Mercury into Venus - waste of planets! It would never cool off in time. And the extra mass in our neighborhood might screw with our orbit here at Earth. Mercury probably is good mining. Lots of metals there due to the density. So you lose that. And how are you going to move it?

Probably the only good way of starting this project is with a solar shield and freeze out the atmosphere. That part is cheap, relatively speaking. But you still have to store or move all that frozen mass. Maybe blast it out into orbit and use the reaction to spin up the rotation. Still too hard!

I also wonder about the geologic history of Venus and what lessons it holds. Lets say you get the atmosphere the way you want it. And say you imported the needed water to get lakes and maybe seas. Hasn't Venus' surface been recently (geologic time) resurfaced with lava flows? Something like 90% of it? What process drives that massive volcanism? Maybe it is due to happen right when your terraforming project completes and all your hard work goes up in flames! Cities sunk in magma!

Mars is really the only planet worth the effort. Venus sucks!

[Betruger]

Floating cities sounds like a pretty good base for processing the atmosphere.

[nyar]

Quite a few of these steps could be done while in transit from Saturn to Venus, especially if you took a low energy transfer orbit inward. The biggest would be the protective/reflective layer for the ices being brought to the inner system.

True, some steps could be done in transit as long as the tidal stresses in the structures during momentum reducing swingbys of inner planets are considered. I see the L5 point as a nice stable industrial construction zone. After escaping from Saturns orbit Phoebe will still have an orbital velocity of approx 7.27 km/sec. A steep elliptical orbit MAY allow for a swingby of an inner planet. However I suspect we'll have to do a swingby of Jupiter to kill enough momentum. If the parasol can be collapsed during planetary encounters then we could get closer to the planet for greater momentum exchange. For the reflective layer I'm in favor of some type of electro vacuum deposition of lighter metals possibly using the constructed ion cannons. If the deposited layer is thick enough it may help to hold the moon together during the momentum killing flybys. Also the stresses may pull the reflective layer free of the surface regolith creating a vacuum space that reduces conductive heat transfer. A lot has to be considered in moving a 200 km moon.

I realize that this effort is for a fully mature, socially stable Type I civilization that is starting towards a Type II. The energy required to get Phoebe out of Saturn's orbit alone will be 1.2X10^25 Joules. That's over twice the energy that strikes the earth's surface in one year.

So we're not going to do it tomorrow. I'm trying to avoid the crash, bang, giant magic hand approach to my strategy and am interested in others who will present calculations to either support of refute my approach. Throwing comets or nukes at the problem just doesn't interest me.

[williatw]

Wikipedia

Venus has an extremely dense atmosphere, which consists mainly of carbon dioxide and a small amount of nitrogen. The atmospheric mass is 93 times that of Earth's atmosphere while the pressure at the planet's surface is about 92 times that at Earth's surface—a pressure equivalent to that at a depth of nearly 1 kilometer under Earth's oceans. The density at the surface is 65 kg/m³ (6.5% that of water).

We can make things that float under the ocean's surface, so can we make habitats that float in the Venusian atmosphere? The internal pressure of the habitat would necessarily be about one Earth atmosphere, same as a submarine. Of course the high temperature would be a problem except at high altitude.

The Surprisingly Strong Case for Colonizing Venus

Science fiction writers have come up with a plausible scenario for a floating city above the fiery planet.

Why worry about building a colony on Mars when instead you could float one high above the surface of Venus? Science fiction writer Charles Stross recently revived the idea of building a Venutian colony when he suggested, cheekily, that billionaires ought to be compelled to donate to massive humanity-improving projects. He suggested two: a Manhattan Project-like focus on developing commercial nuclear fusion, or the construction of a floating city on Venus.

The second planet from the Sun might seem like a nasty place to build a home, with a surface temperature hot enough to melt lead and an atmosphere so dense it would feel like being submerged beneath 3000 feet of water. But the air on Venus thins out as you rise above the surface and cools considerably; about 30 miles up you hit the sweet spot for human habitation: Mediterranean temperatures and sea-level barometric pressure. If ever there were a place to build a floating city, this would be it.

Believe it or not, a floating city might be a feasible project. Scientist and science fiction author Geoffrey Landis presented a paper called "Colonizing Venus" [PDF] at the Conference on Human Space Exploration, Space Technology & Applications International Forum in Albuquerque, New Mexico back in 2003. Breathable air floats in Venus's soupy carbon dioxide atmosphere, which means on Venus, a blimp could use air as its lifting gas, the way terrestrial blimps use helium to float in our much thinner atmosphere.

A sphere with titanium skin 0.04" thick would be able to survive reentry and float a couple of miles above the surface, he argued. Goff, who who describes himself as a space entrepreneur and space settlement advocate, suggests that rocket stages (the parts that drop off of a spaceship during liftoff) could also be engineered to float after use and be re-used, providing a way to and from the colony so that building materials could be mined from the surface. The well-informed space enthusiasts who frequent the Selenian Boondocks also helped Goff map out the chemical processes required to extract breathable air (a mixture of nitrogen and oxygen), water and various fuel and construction materials.

http://www.citylab.com/tech/2014/07/the ... us/373560/