How to render Venus semi-habitable?

Question

It must be very dark and hot on the surface of Venus, but my humans want to change that and make a Venusian colony. The problem? The extremely thick atmosphere would make it problematic to say the least. There would be a contest between heat and atmospheric pressure to see who can do the colonists in first. The colonists solution? Send atmospheric drainage ships into orbit around Venus and extend a giant robotic Proboscis into the Venusian atmosphere.

The gas from the atmosphere will be drained into massive "Drainage Ships" that will be sent to Mars to add some of the atmosphere to it. The rest will be sent away, out of the Solar System. Since Venus is in inner fringes of the habitable zone of our system we can now place a permanent colony on Venus.

Is this realistic? How could I make it more realistic?

Answer 1

Venus is a great place for a colony as long as you don't put it on the surface. About 50 km up the atmospheric pressure is the same as that at earth's at sea level. The temperature at that height there is like the south of France. As a bonus on Venus Air (the stuff we breath) is a lifting gas. Because of the surface albedo solar panels work as well on the bottom and top of your balloon.

There is also a fantastic amount of carbon for making plants and carbon-based tech. The water problem at least for a limited colony could be solved by acid harvesting H+ for the taking.

Answer 2

I proposed something like this in another question, but it might work better here.

Put something in orbit between the sun and Venus to cut down on the amount of sunlight. If you can block it completely, then the atmosphere would basically freeze, and you'd be able to scoop it up or seal it away.

The original suggestion was for some kind of soletta, kind of a giant solar umbrella made from solar sail material, but it would have to be very very big. Other ways that might work would be to ring the planet with a dust cloud, or possibly a cloud of small solar sail satellites, which would reflect the solar radiation and heat away. They could even collect the energy and beam it down to the planet to power the teraforming. When the work is done, you remove some of the satellites/cloud to bring the temperature up to the point you want it, while still keeping it cooler and cutting down on the radiation.

Answer 3

The atmosphere of Venus is a nasty place. The surface is 900 degrees Fahrenheit at 100 atmospheres of pressure. The upper atmosphere has constant winds exceeding 200 mph and sulfuric acid clouds. The major constituent is carbon dioxide, with trace amounts of noble gases, water vapor, and corrosive sulfur-containing compounds. Ingesting this stuff into your spaceship would probably be a bad idea, as would dumping it on Mars.

Note also that removing the thick clouds (again, make of friggin' acid) would expose the surface to intense solar radiation, as Venus's magnetic field is much weaker than Earth's; probably also a bad idea.

(Side note: there would be no contest between temperature and pressure. The later Soviet Venera probes were all done in by the high temperature. It is easy to build something that can withstand thousands of atmospheres of pressure [think of deep-diving submarines], but much harder to make something that can survive a bath in molten lead [and even higher temperatures].)

Answer 4

The Bosh Reaction

The Bosh Reaction lets you turn hydrogen and carbon dioxide into water and graphite. Just by adding hydrogen to Venus, you destroy the atmosphere and create a huge ocean and several meters of ash will cover the ground like snow. The huge amount of graphite might not be desirable, but Venus has basically no water on it, so the new ocean would be appreciated.

Why it is good

I think it's an excellent first step for terraforming Venus. You would have to take huge volumes of hydrogen to Venus, but that's much easier than transporting CO2 away. You'd need in the neighborhood of twice the volume of Venus's atmosphere, but only 1/40th the mass.

You're still looking at billions of trips by millions of ships over thousands of years, such is the nature of terraforming, but 40 times less than taking the atmosphere away in those same ships.

And you can mine hydrogen from lots of sources in the solar system. Low gravity sources. That's a big deal. Pulling ice off comets in the outer solar system to get your hydrogen is much easier than lifting all that atmosphere out of Venus's deep gravity well. Even though you've got to take it so much further.

How it works

The Bosh Reaction makes use of an iron (or nickle or cobolt or Ruthenium) catalyst, so you might be dropping canisters from orbit which vent hydrogen through a screen made of your catalyst material. The Bosh Reaction requires high temperatures, but guess what temperature Venus is? Reaction temperatures are in the range of 450-600°C, and the surface of Venus is right in that range.

After most of the carbon dioxide is gone, the atmosphere of Venus will actually be bigger and hotter than ever before. You wont have an ocean yet, just an atmosphere made of steam. The Bosh Reaction gives a net gain of heat, and the resulting water vapor will be double the volume of the CO2 it was made from. It probably wont cool down on its own because water vapor is a better green house gas than CO2. You'll need a huge orbital sun-shade. You were getting one anyway, right?

Afterwards

It will take years for the planet to get cold enough for the rain to start falling. Then it'll rain for a few more years. Once the clouds have cleared, you'll hopefully have an atmosphere thin and cool enough that humans can walk around in space suits without being smashed or boiled. But, remember that was only the first step. The atmosphere will be made of nitrogen, residual CO2, Hydrogen, and Methane. As well as all those sulfur compounds which where there in the first place. You also need to figure out what to do with all that carbon on the ground. This is just the beginning.

Answer 5

CAPTURE AN ASTEROID

First we need an Asteroid: Something with a lot of mass, possibly Ceres or Vesta although we could use just about anything with enough mass, like one of the smaller moons of Jupiter, Saturn or Uranus. We place the orbit around Venus. We make the peri-venusian point REALLY close to Venus's atmosphere. Enough so it pulls off a small but significant amount each time it orbits. And if we did our math right, it's going to orbit around Venus for a very long time. This solves our atmosphere problem, albeit very slowly.

We need to strip off more atmosphere: But we probably don't want this to take millennia so let's do something more to speed up the process, plus we're eventually going to need to do station-keeping to make it STOP pulling atmosphere off of Venus. We build mirrors. Big mirrors. And we aim them at our planetoid and vaporize the rock. Near the surface (in fact, we could put them ON the surface) we place positively charged plates. These plates will cause the super-heated rock to vapor deposit onto our plates. If we place them right, with the right charge, we can even pull nearly pure iron off onto it's own plates. Other materials would require some other type of purification, perhaps something close to a refinery by placing plates near the fractionation points of different materials similar to an oil refinery. We do this for two reasons. First, we're greedy and want the raw materials. Second, because if we change the distribution of mass in our planetoid, it will change it's orbit without the need for reaction mass.

We need to reduce solar radiation: Now that we have a huge supply of raw materials for nearly free, we're going to build a series of solar panels and place them into the first Lagrange point between Venus and the Sun (and if that's too far away, as it most likely is, we'll put them into a Venus-synchronous orbit around Venus where they stand between Venus and the sun). We're going to put LOTS there. Enough to change the albedo of Venus and reduce it's surface temperature as well as block a significant amount of incoming radiation.

We need to remove the poison out of the atmosphere: Once the surface temperature cools, the active leeching of poisonous materials from pressure and heat on the surface will begin to lessen and then stop. This means the rocks will re-bind most of the poisons in the atmosphere back into the geology for us.

We can speed up the removal of the atmosphere: Also, by using our large laser array, we can ionize the atmosphere, further bleeding it off into space.

Answer 6

Exporting the carbon dioxide from the Venusian atmosphere is not the most effective way of terraforming the planet. It isn't realistic. This answer offers an alternative.

Fortunately, if you have this level of space technology there are better options. What you need to do is a three step process.

First, convert atmospheric CO2 into carbonate rocks. Most of Earth's CO2 is locked up in the form of carbonate rocks. To do this, just add water, Actually a ginormous amount of water. Fortunately, the solar system is chock-a-block with astronomical bodies full of water. Europa, Ganymede, Enceladus, and, possibly, even the dwarf planet Pluto. Instead of using Drainage ships to capture the Venusian atmosphere, use similar sized interplanetary vessels to import the equivalent of the Earth's oceans from Europa, Ganymede and etc. Dump the water in Venus' atmosphere and allow geochemistry to take its course. Thus, converting atmospheric CO2 into carbonate rocks.

Secondly, build a system of solettes as discussed in AndyD273's answer, to block out excess insolation (basically, sunlight) and allow the planet to cool down to acceptable temperatures. Once human settlers are living on an eventually habitable Venus this can be modulated down to Earthlike levels of solar radiation.

Thirdly, introduce photosynthetic organisms into the Venusian oceans and seas. These will convert the remaining CO2 into an oxygenated atmosphere. The original proposal by Carl Sagan, using algae, is now regarded as dubious science. However, a technological civilization capable of terraforming Venus will have more advanced biotechnology and will be capable of producing suitable organisms to do the job.

While the three-step process of terraforming is scientifically plausible, it should come with the following product warning.

Terraforming planets to human levels of habitability will usually geologically long periods of time.

This does mean millions of years. It's really a problem of scale. Easy to overlook the amount of change required on a planetary scale to terraform a planet. Don't be in a hurry to pack your bags for a move to Venus in the near future.

Answer 7

The mass of the atmosphere of Venus is round-about 4.8E20 kg. The largest ship ever built is the Seawise Giant at 657,019,000 kg. It would require just 700 billion trips, assuming it could be made to get from here-to-there with cargo at the density of oil. And completely neglecting what it will use for fuel and reaction mass. I would say that's not feasible unless you invent some crackling new forms of space travel.

If you just want to get the gas off of Venus and don't mind ejecting it into space, you could build structures that ionized the atmosphere and jetted into interstellar space. You could make these things solar powered. Escape velocity from the neighborhood of Venus to interstellar is something-like 50 km/s, plus the 10 km/s to get away from Venus's gravity, so a total of 60 km/s. That's probably do-able.

You would need some HONKING big accelerators. Venus has an area of 460 million sq km. So if you could build 1000 accelerators that were each 1 sq km in area, and pumped a full column of air out in 100 seconds, it would require 540 years of operation to get rid of the required atmosphere. You might need to use most of the area of Venus to get enough energy from solar collectors.

So, no, I would not call that feasible either.

Answer 8

The only realistic way of making Venus more habitable is to add some microbes that can transform carbon dioxide to carbon and oxygen in solid or liquid form and to gaseous oxygen, in a process similar to photosynthesis. The microbes will have to live approximately 5 km up in the atmosphere, where temperature and pressure is similar to what it is on the Earth's surface. The produced oxygen has to combine with hydrogen, from the solar wind, to form water, maybe catalyzed in the microbes. Organic compounds will snow or rain down on the surface. The atmosphere will thus decrease in volume and the surface temperature will drop due to lower pressure at the surface. At some point the temperature will drop enough to make the water vapor condense and liquid water on the surface will be present for life.

The biggest problems seems initially to be shortage of water and shortage of hydrogen. This will make the process take long time.

A similar process once took place on Earth and it lasted hundreds of millions of years.

The Outer Space Treaty from 1967 is an international agreements against migrating life to other planets. This agreement first needs to be abandoned, or the space vessel could be sent up from a non participatory state.

Sending a capsule with such bacteria to Venus is not a demanding task. A small group of people can do it.

Answer 9

Laser Death Ray Terraforming

• build huge solar powered lasers close to the sun

• tune them to a UV-wavelength (for laser range), which CO2 absorbs almost completely

• blast Venus for a few years until the atmospere looks acceptable

This means that you attempt to get rid of as much CO2 as you can without loosing too much N2. If the rate of N2 loss is only ten percent of that of CO2 loss, only 0.3 atm N2 are lost while the CO2 has been removed almost completely. It might be possible to ionise the escaping CO2 in order to capture it with an electromagnetic tether megastructure around Venus.

• import hydrogen gas from the outer solar system to produce water

• cover everything but the poles in reflective foil

• colonise the poles with buildings on stalks

• wait until the planet cools

Not really the most economic way to terraform Venus, but one of the quickest. This could probably be done within a decade with some lunar or mercurian industry. Also, the 3 bar nitrogen atmosphere and the resulting light nitrogen narcosis is a feature, not a bug.

Answer 10

How about using funnel in the atmosphere leaked to outer space. Wouldn't that drain the poisonous atmosphere? Space is the ultimate vacuum ya?