Terraforming Mars

[Albert VDS]

Cost and fallout and hugely overpowered for traveling around the corner..

[Rondon]

Cost and fallout and hugely overpowered for traveling around the corner..

Not overpowered when you're trying to move a celestial body however. The fallout would be political nightmare, putting it in orbit removes the fallout risk, but adds to the already gigantic cost, but that's the thing, chemical propulsion and nuclear engines are just hundreds of times less efficient, so they'd cost hundreds of times the already titanic cost of the Nuclear approach.

[m4rt14n]

Well it would probably cause a lot of energy exchange, partly in the form of heat, but the most important thing to note is that it would destroy Mars.

Would there be an optimum size asteroid(s) to pummel mars with that would not cause it to be destroyed?

[Motokid600]

Every city would need a gigantic dynamo to produce an artificial magnetic field. Doesn't matter if you can breathe the atmosphere. That's what terraforming Mars comes down too. I said it once ill say it again the notion of completely, 100 percent terraforming a planet is ridiculous. There are far better, cheaper ways of sustaining a mass populace on another world. Biodomes.. biodomes everywhere.

[m4rt14n]

But.. but.. I want another blue and green globe in the Solar System...

(Taken from wikipedia)

[SargeRho]

No, that's actually not true at all. You do NOT need a magnetic field once the atmosphere is at breathable levels. The Atmosphere is what shields us against radiation, not the magnetic field. Right now the radiation on the surface of Mars is equivalent to low earth orbit, according to Curiosity.

[Idobox]

Also, in some situations, terraforming could actually be the cheap and easy solution, but it's not the case for any known planets.

For example, if Venus was just too a little too hot with a pressure only a few times higher than Earth, terraforming it by capturing CO2 would probably be a viable option.

[SargeRho]

Well, we can Terraform Mars with relative ease. It would be very ressource-intensive though, as we'd have to build thousands of production facilities that produce super-greenhouse gasses. But those could be built from materials on Mars. If we colonise Mars, it would be the colonists who'd have the highest stakes in Terraforming it.

[RuBisCO]

First: Raise mars temperature

One could either use gigantic orbital mirrors out at Mars-Sun L2, or produce a supergreenhouse gas on mars, I would prefer sulfur hexfloride, its extremely stable, very dense and the most powerful greenhose gas known to man. besides that Zubrin covers the rest: http://www.users.globalnet.co.uk/~mfogg/zubrin.htm

[Roastduck]

Are any of these super greenhouse gases being mentioned safe to breathe? If not, how do we get them out of the atmosphere once the temperature raises, and how do we maintain the temperature without them?

[RuBisCO]

Sulfur Hexfluride is safe to breath (as long as you also bring in your requirement of oxygen, no inert gas is safe to breath pure of course), it also hilarious gas to breath:

[peadar1987]

The atmosphere of the earth has a mass of 5E18kg, as a simplification, let's say that Mars would need half this mass for a surface pressure of 1 bar (its surface area is 1/3 that of earth's, but the lower gravity means you need more gas for the same pressure). That's 2.5E18kg.

Most comets are suspected to be composed of water ice, frozen CO2, ammonia, CO and other volatiles.

To me, it seems like the best solution is to piggyback small nuclear-powered ion thrusters (ideally ones that can mine fuel from comets) onto asteroids and comets of suitable composition, and nudge their orbits so they will at some point impact Mars, in such a way that maximum heat is generated without blowing too much of the existing atmosphere into space. Learning how to redirect comets and asteroids is a useful exercise anyway, and best we learn how to do it before one is heading for earth!

Halley's Comet has a mass of 3E14kg, so you'd need 8,000 of them to impact Mars before you had enough mass. However, many comets are estimated to be bigger (for example, Hale-Bopp was estimated to have a diameter 4 times that of Halley, meaning a mass 16x, so you'd only need 500 of those impacts).

Harvesting Neptune Trojans might be another idea. I doubt you'd need much delta-V if you had enough time to engineer a gravity assist in the Neptune system. In a couple of hundred years, you'd comfortably have enough volatiles to constitute a nice, thick atmosphere. There are estimated to be 800-1000 trojans of Neptune of the order of 40km in diameter and above, which implies a mass of at least 20-25 times that of Halley's comet, so you'd have enough to give Mars an atmosphere twice over, and still have enough trojans left to set up a high-velocity impact with Venus to blow away some of its atmosphere if you wanted.

Then you can get the atmosphere processors and genetically-engineered microorganisms to start converting that CO2, ammonia, and water vapour into something breathable, with a hefty greenhouse effect.

Edited February 21, 2014 by peadar1987

[MBobrik]

The first thing ( or the second if you decide to smash some comets into it first ) to be solved is to build a ring of nuclear power plants around the equator and a big superconducting power line to restore the planet's magnetic field. Because mars has weaker gravity, and no volcanism to replenish its atmosphere naturally, the magnetic field has to be much stronger than earth's to keep atmosphere loss close to zero. It would be a pointless waste of resources to increase atmospheric pressure just to see it being eroded away again by solar radiation.

[peadar1987]

The first thing ( or the second if you decide to smash some comets into it first ) to be solved is to build a ring of nuclear power plants around the equator and a big superconducting power line to restore the planet's magnetic field. Because mars has weaker gravity, and no volcanism to replenish its atmosphere naturally, the magnetic field has to be much stronger than earth's to keep atmosphere loss close to zero. It would be a pointless waste of resources to increase atmospheric pressure just to see it being eroded away again by solar radiation.

That would take hundreds of millions of years though. Look at Venus: Far closer to the sun, no magnetic field to speak of, but wow, that atmosphere!!

[MBobrik]

That would take hundreds of millions of years though. Look at Venus: Far closer to the sun, no magnetic field to speak of, but wow, that atmosphere!!

Big and bone dry because the hydrogen is the first to go. And this process is much faster on a lighter world where the outer atmosphere reaches further out into space.

[Nuke]

what i would do is grab a couple large asteroids and slam them into the ice caps. that should increase the heat of the surface and add some density to the atmosphere.

but i have a feeling without a magnetosphere the atmosphere would get blasted away in time, so any terraforming would be temporary, but would give you enough time to build up infrastructure for a post atmospheric mars. you might be able to set up an artificial magnetosphere with a sufficiently large power source.

the other option is to do a longer terraforming process (on the order of millennia), where larger asteroids, as well as deimos and phobos (they would spiral in eventually anyway), are slammed into mars until a dynamo effect is established. these would all be glancing blows to induce rotation of the core and possibly form a new moon. then you must wait for the crust to cool off sufficiently and begin bacterial (obviously genetically engineered mutant super germs) modification of the planet. slow but i figure its the best chance for a long term habitable mars. once the atmosphere is breathable then you begin engineering an artificial ecosystem and colonize.

Edited February 21, 2014 by Nuke

[peadar1987]

Big and bone dry because the hydrogen is the first to go. And this process is much faster on a lighter world where the outer atmosphere reaches further out into space.

I still find it hard to believe that this will be particularly significant over any sort of timescale, although I'm open to correction on this. I would have though that if we have the technology to capture comets or icy asteroids, it would be far simpler just to capture one every couple of centuries, rather than using what I assume is several Terawatts of power to produce a constant, planet-sized, magnetic field.

[Motokid600]

What Mars needs is for Olympus Mons to erupt again.

[AngelLestat]

First we would need to know more about the greenhouse effect, there is still some doubts how this process work. For example at Venus there are some things that does not seems to match with the earth models about greenhouse effect.

And if we go wrong about this, then we can throw away all our efforts to terraform.

But if our theories are right, then yes. Try to search a way to activate a chain reaction would be the way to go.

[SargeRho]

Venus has very little nitrogen, very little water vapor, and a pure CO2 atmosphere. It also has sulphuric acid clouds which as far as I know, reduce the greenhouse effect. And Venus does seem to roughly match our models of the greenhouse effect.

[Rondon]

MBobrik , from what I've heard mars could hold onto an earth like atmosphere for about a million years.

Peadar1987 in terms of ion engines using quick calculations: for an idea of how much a earth like martian atmosphere would weigh well use your figure of 2.5x10^18, presuming we could find a perfect comet (100% of material would create atmospheric gas), using what looks like the highest figures for energy per kg of exhaust from a design, currently under development the "dual-stage 4-grid" which produces 22500 MegaJoules per Kg, (for comparison VASIMR has 1400 MJ/Kg) using this figure and presuming you need to give the comet 1000m/s for it to collide, it would take 100 billion Kilograms of propellant, and that's for the rarish material that Argon is, getting the infrastructure set up, to mine that much uncommon material might take an impossible amount of work.

You would also need 3x10^21 joules of energy to move it in the first place and that's just about the amount of energy the entire human civilization uses in six years! the energy required is just so massive, that you'd have to wait for or split the cost over centuries before it could be undertaken.

[peadar1987]

MBobrik , from what I've heard mars could hold onto an earth like atmosphere for about a million years.

Peadar1987 in terms of ion engines using quick calculations: for an idea of how much a earth like martian atmosphere would weigh well use your figure of 2.5x10^18, presuming we could find a perfect comet (100% of material would create atmospheric gas), using what looks like the highest figures for energy per kg of exhaust from a design, currently under development the "dual-stage 4-grid" which produces 22500 MegaJoules per Kg, (for comparison VASIMR has 1400 MJ/Kg) using this figure and presuming you need to give the comet 1000m/s for it to collide, it would take 100 billion Kilograms of propellant, and that's for the rarish material that Argon is, getting the infrastructure set up, to mine that much uncommon material might take an impossible amount of work.

You would also need 3x10^21 joules of energy to move it in the first place and that's just about the amount of energy the entire human civilization uses in six years! the energy required is just so massive, that you'd have to wait for or split the cost over centuries before it could be undertaken.

Well I was proposing using an ion engine that used the comet itself as reaction mass. It wouldn't be as efficient, but theoretically, ion engines can run on anything that can be ionised. You'd need a special design, but hey, we're talking about terraforming Mars here, nobody said it was going to be easy!

As for delta-V requirements, I honestly have no idea how much you'd need, but I'd hope with clever gravity assists, you could get it down to well below 1km/s (time isn't really an issue, I'm working on the theory that we have hundreds, or even thousands of years). It only takes 270m/s to get from Neptune to Uranus orbit, for example. To give a comet of the mass of Halley's comet (3E14kg) a delta-V of this much, you'd need 1.35E19 J of energy. That's still a lot (an awful lot). By my calculations, even if you could allow for 10 years of total burn time, you'd need to have 42GW of power available. Comets and other bodies that already cross Mars' orbit might need less delta-V, halving the requirement will obviously quarter the energy demand.

So now I look more closely at the numbers, you're right, it would be in no way easy or quick. On the other hand, would it be any easier or quicker than genetically engineering bacteria to make the atmosphere for us? I have no idea. Just a suggestion.

[Nuke]

just use a mass driver.

how to power it? we will have fusion long before we have terraforming.

Edited February 22, 2014 by Nuke

[Tex_NL]

Call me skeptical but I see a lot of problems with what is proposed thus far.

- Dropping nukes to raise the temperature? OK, it might work but you'll irradiate the surface rendering it inhabitable for millennia.

- Dropping asteroids to supplement the atmosphere? It will kick up megatons of dust, blocking the already spares sunlight and reducing the temperature. (And it is extremely risky. One minor miscalculation and you'll wipe out all life on earth.)

- Moving an entire moon? I don't know what you guys have been smoking but it has seriously messed with your sense or reality.

- Biodomes. Finally a suggestion that makes sense. They are relatively easy to build and maintain. And they won't 'waste' resources on area's (continents) you don't use.

And now for the final nail to the coffin:

There is not nearly enough water on mars to transform it into another blue planet.

Both the northern and southern icecaps are between 2 and 3 kilometer thick and contain a combined volume of roughly 3.2 million cubic km of ice. Lets assume we can indeed melt it all. A significant portion of this will evaporate into the atmosphere while another large part will be soaked up by the bone dry soil. Spreading the remaining water over the planet surface will result in .... a muddy puddle and possible a hand full of minor lakes.

There simply is not enough water to cover the planet with vast lakes and oceans!

[Dispatcher]

This IS a discussion about possibilities, as opposed to probabilities. Any real Martian terraforming would require enormous amounts of effort, energy and time.

As for turning Mars into an ocean paradise; I don't think anyone here really expects that, artwork notwithstanding. However, melting the polar ice (of which much of it is CO2) would increase the air pressure. I also don't expect that we'd see the surface of Mars attain one BAR of pressure. I think we'd be lucky to attain half that. The remaining water melt will not form oceans or seas. However what water is there would add moisture to the ground, humidity to the air (which would not be breathable) and some seasonal streams, rivers and possibly lakes. There would really be some crater lakes there.

If there is no native flora (algae-like or bacterial) which can generate oxygen, we'd need to introduce it and seed it there. According to Phoenix lander data, the "soil" contains chemical nutrients. Even then, it would take a long time before anyone could breath the air in situ.

In the meantime, we should take care of planet Earth.