Terraforming Mars and Venus

[Da Blob]

This is a question which I can't even begin to answer. In order to make Mars and Venus habitable for human life the surface temperature of
Venus has to be lowered dramatically, while the surface temperature of Mars would have to be raised dramatically.
One way to accomplish this would be the construction of a deflector/lens in close solar orbit(?) that would deflect solar energy from Venus onto Mars.
So how big would such a device have to be to be effective?
What would be the optimum orbit? How fast a change in surface temperatures could be elicited?
The moon could be mined for basic raw materials for the device(s) etc.
Are there really any technological hurdles involved in the implementation of such devices or is simply a matter of scaling up existing technology?

EDIT -BTW has anyone calculated candlelight per square kilometer in terms of A.U.s?

 

[Latro]

That wouldn't really be practical, because of the way the orbits of Mars and Venus work. There are times when Mars and Venus are on opposite sides of the Sun, times when they're on the same sides of the Sun, etc. Doing what you're describing on Mars would require you to simply deflect the Sun's rays from Mars' orbit down onto Mars; the mirror in question, if I remember correctly, would be on the order of square miles in area (this has in fact been proposed, however, and is theoretically feasible). This is because Mars' average surface temperature is about 210 K; we'd need to raise that to about 290 K to be comfortable. (I'm using Kelvin so that my temperature comparisons actually make sense).

Doing what you're describing on Venus just isn't practical; you're talking about deflecting far too large a proportion of the rays that hit it to create the necessary effect, because Venus' average surface temperature exceeds 700 K. This doesn't even take into account other issues, like rain which comprises concentrated sulfuric acid and surface atmospheric pressures around 90 atm.

By the way, putting an object into close solar orbit (as opposed to Venus' or Mars' orbit) would be very hard. The kinds of mass that would be necessary to keep an object directly orbiting the Sun (as opposed to simply falling into it) are very, very high, higher than we could likely produce.

 

[Coelacanth]

Even once you've got the temperature right, there's still the question of atmospheric composition -- one has 100 times too much pressure, the other 100 times too little, and neither has any signficant amount of oxygen (and I suspect in the case of Venus, thinning out the 90 atmospheres of carbon dioxide could materially help with the temperature situation -- it is a greenhouse gas, after all).

Also, rather than trying to fling solar raditation in an ever-changing direction across an ever-changing distance of 70-200 million miles, mightn't it be easier to simply block the radition to Venus (send it out perpindicular to the ecliptic or something) and collect additional raditation with mirrors orbiting Mars? That way you don't have to cope with the problem of aiming the beam quite as much -- hardly at all in the case of Venus and probably just from geosynchronous (martiansynchrounous?) orbit around Mars. Or, for that matter, just paint Mars black.

 

[Da Blob]

Good points. It would be unrealistic (although effective) to think that a single device could serve a dual purpose. There would have to be a series of mirrors employed. However, the problem would not occur with the devices falling into the sun because of gravitational pull. Supposing that the surface of the deflector would be perhaps 2 ml thick, perhaps created from the plastic byproduct of algae grown in space, the problem would be to keep the devices close to the sun because of the solar wind pushing them away... They would in structure resemble solar sails...

 

[Latro]

Good points. It would be unrealistic (although effective) to think that a single device could serve a dual purpose. There would have to be a series of mirrors employed. However, the problem would not occur with the devices falling into the sun because of gravitational pull. Supposing that the surface of the deflector would be perhaps 2 ml thick, perhaps created from the plastic byproduct of algae grown in space, the problem would be to keep the devices close to the sun because of the solar wind pushing them away... They would in structure resemble solar sails...

I'm fairly certain that unless you have propulsion, you will fall into the sun if you don't have sufficient mass and try to enter direct solar orbit. I'd like a little more than a bit of handwaving about solar wind pushing them away before I'm gonna change my mind...and google didn't help much. All I got was a few papers about "strepulsion", which, while ostensibly by PhDs, also have no references, which is uncommon even in works by PhDs. They also, while admittedly claiming to be Indian, write in a very clunky manner (grammatical errors etc. are rampant). They also make certain claims (e.g., if gravity was the sole force involved the inverse square law for newtonian gravitation would not hold) without support or references.

Link:
http://strepulsion.org/partiv.htm

 

[Da Blob]

Yeah ditto on google. I can't even come close to finding out what the intensity of sunlight is on Mars. The info I have on solar sails is outdated as well. I will try wiki. I just remember that solar sails were once suggested as a means of interstellar propulsion and the numbers presented at that time made a feasible option.

 

[Latro]

Yeah ditto on google. I can't even come close to finding out what the intensity of sunlight is on Mars. The info I have on solar sails is outdated as well. I will try wiki. I just remember that solar sails were once suggested as a means of interstellar propulsion and the numbers presented at that time made a feasible option.

By what I recall about solar sails, they didn't work the way you're describing. They worked by soaking up solar radiation in what essentially amounted to a large solar cell and then using that to generate thrust (via an engine). This would then allow for a lightweight propulsion system, largely because the source of the thrust would not have to be carried onboard; this would in turn dramatically lessen the required weight of the vessel. I do not think it has anything to do with direct propulsion by solar wind.

 

[Da Blob]

By what I recall about solar sails, they didn't work the way you're describing. They worked by soaking up solar radiation in what essentially amounted to a large solar cell and then using that to generate thrust (via an engine). This would then allow for a lightweight propulsion system, largely because the source of the thrust would not have to be carried onboard; this would in turn dramatically lessen the required weight of the vessel. I do not think it has anything to do with direct propulsion by solar wind.

Wiki does have a good article on solar sails, apparently it's a hot area for research. You are right and wrong. One type of solar sail is pushed by the mass of protons, just as a conventional sailboat is pushed by the mass of air molecules. the other type converts magnetic waves into propulsion energy.

Edit:Okay I got some numbers. According to the figures I got it would only take a deflector 25 squared km in size sharing an orbit with Mercury to boost the sunlight received on Mars to equal that received on Earth. However large of a shadow this size of deflector might cast on Venus seems to be insufficient to change the temperature of Venus... It would seem that one might have to have a deflector close to the diameter of Venus to put enough of the planet into permanent eclipse to cause a significant change in temperature...
Edit: at a maximum of a 1mm thickness that deflector would occupy a ridiculously small volume...

 

[Ermine]

I don't know about current proposed plans and what is or isn't practical but I just wanted to run this idea by you all.

What about somehow containing and transporting our excess greenhouse gases to Mars?
And what about engineering plants to survive the harsh and cold conditions of Mars so they can soak up the CO2 and create an oxygen supply there? Or would it be more practical to just bring our own oxygen supplies?

 

[Latro]

I don't know about current proposed plans and what is or isn't practical but I just wanted to run this idea by you all.

What about somehow containing and transporting our excess greenhouse gases to Mars?
And what about engineering plants to survive the harsh and cold conditions of Mars so they can soak up the CO2 and create an oxygen supply there? Or would it be more practical to just bring our own oxygen supplies?

Trying to do fractional distillation of air on the scale that you're talking about would be a huge, huge project, using ridiculous amounts of energy. Probably a more efficient way to transfer CO2 to Mars would be to bring methane and oxygen; that way you'd get CO2 and also get energy. Really, though, even if you brought all our greenhouse gases to Mars, you probably wouldn't get up to 290 K there. (You'd also lose it eventually to solar/cosmic radiation (Mars lacks a magnetic field) and lower gravity). In the end you probably would wind up needing to get an energy source to heat up a colony, whether by a mirror technique or something else.

Plants probably wouldn't be the way to soak up CO2, at least not initially, by the way; you'd be better off with photosynthetic extremophilic bacteria, which would require fairly little bioengineering, if any, to sustain on Mars, as far as I know. But then of course you have the scientific/ethical issue of them potentially killing what little tiny bit of life there might be there.

Da Blob: are you sure the deflector wouldn't have issues with spreading out in all directions, or with delay, or things like that? (I can't see your math, so I can't tell).

 

[Anthile]

You should also consider that transporting costs are ridiculously high and even if there was pure gold on the moon it would barely refinance itself. Not to mention the high risk for extremely expensive machines and workers. With our current technology absolutely unthinkable.

Also, considering that just a Mars exploration would cost about 400-500 billion dollar, it is no project that one nation alone could finance.

 

[Da Blob]

You should also consider that transporting costs are ridiculously high and even if there was pure gold on the moon it would barely refinance itself. Not to mention the high risk for extremely expensive machines and workers. With our current technology absolutely unthinkable.

Also, considering that just a Mars exploration would cost about 400-500 billion dollar, it is no project that one nation alone could finance.

Oh! I don't know about that the US Government throws away chucks of money that size all the time. They gave that amount to an obscure organization called ACORN recently. Some type of political payback if I understand it... One of those things that makes it impossible to have faith in the American government...

One would hope that at some point in time a propulsion system would be developed that would drive transportation costs way down. My bet is that a type of magnetic drive will be developed...

 

[Seducer of the Homeless]

much more interestingly, tying all this science in to metaphorically describe the Male/Female mysteries

 

[Inappropriate Behavior]

They gave that amount to an obscure organization called ACORN recently. Some type of political payback if I understand it...

Dude, seriously. 400-500 billion to ACORN? You have got to stop watching FOX news and/or listening to am radio.

 

[Inappropriate Behavior]

As to the topic of the thread:

I don't believe it is feasable to terraform Venus so I'm not going to get into that.

Mars as I see it needs 3 things to happen:

1. A viable human friendly atmosphere
2. Increase in temperature
3. Water (I know it is suspected to exist there but is it proven?)

Because of Mars size, it's gravitational field isn't enough to trap gasses or hold gasses we put there ourselves. It will be like a ballon with a very small leak. So question: Could we increase Mars' mass? Using the nearby asteroid field? It would probably take forever but so will this project anyway. As to the lack of a magnetic field, I have no idea what to do about that.

The use of orbital mirrors could help raise the temperature but what about geothermal energy? Is there a hot enough core to tap into? It would involve a very big drill of course.

Water, if it isn't already there, can possibly be obtained elsewhere in the solor system. I haven't looked it up for this post but isn't one of Jupiter's moons covered in ice? What about the debris that makes up the rings surrounding the gas giants?

As you can tell, I'm in over my head on this so I'm just throwing ideas out there.

PS: Da Blob, if you haven't read them already, Kim Stanley Robinson did a trilogy about Mars (Red Mars, Green Mars, Blue Mars) that was very techy in it's descriptions on efforts to terraform Mars (and other parts of the solor system). You might find them interesting.

 

[Da Blob]

Dude, seriously. 400-500 billion to ACORN? You have got to stop watching FOX news and/or listening to am radio.

LOL I neither watch TV or listen to the radio - too much propaganda. My source for that figure was a comment on a friend's post on facebook concerning TARP funds. However, I guess I could have pointed to the fact the government spends trillions of dollars prolonging the death experience of those on medicare... Most of the money spent is during the last four weeks of a person's life...

EDIT: I just now got notification of the previous post.
I have Read all Of Robinson's work, my favorite is the one about the planet that is a preserve for a protected species whose wings produce a great drug...
One of Jupiter's moons is composed completely of H2O there are even water volcanoes, where 'superheated' i.e. liquid H2O erupts onto the surface...
The question of generating a large scale magnetic field is a major obstacle though...