Increasing mars atmosphere by chemically splitting Phobos

[goran d]

Phobos is has low enough orbit that if we were to chemically split it to release gases such as oxygen and carbon dioxide most of them will be captured by Mars. And its mass is comparable to the Martian atmosphere. If we chemically split most of it it could increase Mars pressure by maybe 15-20%.
Two options -  10^12 m^2 mirror and 100000k 20mt nuclear bombs.
In both cases the launch cost will be roughly 5 - 10 trillion $, using current launch prices.

[ppnl]

Or you could just split materials on the surface of Mars...

[MATTBLAK]

And using so many nukes would just introduce a vast quantity of radioactives into the Martian environment.

[redliox]

Phobos could be useful as raw material in any large scale projects, terraforming being an obvious one.  Carl Sagan once suggested basically smearing Phobos across the Martian poles to heat them up - how that'd be done I don't know but that would be less intense than nuking the moon.

If you want to increase the atmosphere with less radiative material, a suggestion I'd make would be inducing a bombardment of comets into its southern (already cratered) hemisphere, so long as you ensure you don't cause any of the atmosphere to leak and past impacts may have caused.

[Lar]

Yeah I think gathering up a bunch of uninteresting comets from the Oort cloud and sending them inbound is a better way to add volatiles than sacrificing Phobos

[alexterrell]

Third option is to lower Phobos mass in a tether, until it reaches a Mars capture orbit. The rest of Phobos goes up, and can be used to make orbital mirrors to heat the planet.

[stefan r]

Phobos is has low enough orbit that if we were to chemically split it to release gases such as oxygen and carbon dioxide most of them will be captured by Mars. And its mass is comparable to the Martian atmosphere. If we chemically split most of it it could increase Mars pressure by maybe 15-20%.
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Who would benefit from increasing gas pressure from 0.006 atmosphere to 0.0072 atmosphere?

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the launch cost will be roughly 5 - 10 trillion $, using current launch prices.

If you have a $5 trillion budget you can build orbital rings and a significant economy in space. 

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Two options -  10^12 m^2 mirror and ...

Mirror will be confiscated and used for astronomy.  Maybe used for space based solar power.

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 100000k 20mt nuclear bombs.
In both cases the launch cost will be roughly 5 - 10 trillion $, using current launch prices.

Nuclear bombs are not really a good way to move objects. 

Current launch prices to low earth orbit is are around $10,000/kg.  Bombs with 20 megaton yields weigh more than 4 tons.  If "100000k" means 10⁸ nuclear physics packages then your launch costs might be in the right ballpark.  Humanity does not have 100 million plutonium trigger devices.  The department of defense currently spends several million dollars per nuclear warhead.  You would need drop the production cost a lot or your project price tag rises over $400 trillion.

You would have to add the security cost generated by dealing with anti-nuclear insurgents and the economic costs of an embargo.  It is probable that we would see an impeachment or coop long before an insurgency got rolling in the USA.  The embargo would be in place faster than industry could shift to start working on the project. Fortunately this idea could be disposed of without a coop, insurgency, or international embargo against the USA because the election cycle in the USA is shorter than the time it would take breeder reactors to make the plutonium. 

 

[Hominans Kosmos]

How many kilograms of Nitrogen can you lift from Earth to Mars for 5 trillion dollars?

How big a a solar powered rocket fuel factory and shipyard can you build for 5 trillion, on Mars? For building miners and tankers to skim the atmosphere of Venus and Titan. For importing back to Mars.

[Patchouli]

From a delta V stand point it would be easier to get the nitrogen from Titian and Kuiper belt objects.
Terraforming Mars would be such a long term project the travel times from the outer solar system would not be a big problem.

[Lampyridae]

Yeah, not really viable. Sending stuff inward from the outer planets is all pretty much the same delta V. Triton and Pluto have nitrogen ice just lying around on the surface; it's slushy and you can just scoop it up with a bulldozer, load it into a tank and sling it at Mars with your choice of mass driver, skyhook, or unfeasibly large rocket.

Atmosphere is heavy stuff. Just sitting at your desk on Earth, you have the mass of an adult African elephant over your head. Even the mass of Mars' atmosphere is 25 quadrillion tonnes or about 17 000 cubic kilometres of dry ice which makes a cube 25.5km on a side*. Alternatively, that's a bit over a hundred Halley's comets in mass. Just to double the atmosphere. Since comets are 80% water and 15% CO plus 5% CO2, methane and NH3, you'd need like two thousand Halley's comets for atmospheric thickening.

To get Mars' atmosphere anywhere near the Armstrong limit of 60mbar just by importing atmosphere, you would need a cube 54km on a side or 2 500 O'Neill colonies filled with CO2 ice. China's entire annual coal production burnt as CO2 would add 0.05% to Mars' atmospheric pressure.

The bottleneck is really how fast you can mine and load material. Titan atmosphere would still have to be scooped, compressed and liquified which requires large, complex moving parts. Digging up solid stuff is always quicker and easier, with higher mass throughputs. Someone might think of a clever solution, though.

For nitrogen ice which has roughly the same density as water ice, if you scooped up Sputnik Planitia on Pluto down to a depth of one kilometre, you would get 40 Mars atmospheres' worth of nitrogen which would raise atmospheric pressure to about 1/4 that of Earth. Add in O2 for 40% concentration, and you would have 620mbar at Hellas Planitia and mount Everest air pressure everywhere else.

Not bad for 16 000 O'Neill colony sized megafreighter trips. Or quadrillions of little liquid nitrogen tanks, but I think the economics favours megafreighters at these scales not to mention the navigational nightmare of billions of "small" nitrogen tanks pelting Mars every M-year, each of which has the kinetic energy of small nuclear weapons. 

Pluto only has an escape velocity of 1.2km/s so a fusion-powered megafreighter using water ice as reaction mass would only need a mass ratio less than one. And as a bonus the structural components could be made of water ice, and be delivered with the nitrogen ice. Windows open up roughly every Martian year.

Or, you could just build tens of thousands of O'Neill colonies and live in them. Or make very big domes on Mars, or even just roof it over like Battle Angel Alita.

*based on a density of 1.5g/cc but under Martian conditions CO2 ice is in fact around 1.7g/cc

[ppnl]

Again use the elements already on Mars first. It just takes energy to free oxygen. The big problem is nitrogen. Nobody knows if there is enough locked in on the surface but look for it there first. If it isn't there then you have a problem.

[Patchouli]

Again use the elements already on Mars first. It just takes energy to free oxygen. The big problem is nitrogen. Nobody knows if there is enough locked in on the surface but look for it there first. If it isn't there then you have a problem.

True making use of locally a available materials would make things a lot easier some good Mars has nitrates so you can probably find enough for large domed habitats it's unknown if it's enough to contribute a large part of a planet wide atmosphere.
Of course making Mars completely Earth like where you don't need any kind of pressurized habitat would be a very long term project that will take centuries even millennia which is why I think raiding the Kuipler belt for volatiles would be worth the effort as it doesn't matter if it takes decades for a comet to be bought to Mars.

[jensfridthjof]

Mars would need a magnetic field to retain these gases? Somebody has a big magnet somewhere?  Or is it possible to build one?

[Lar]

Mars would need a magnetic field to retain these gases? Somebody has a big magnet somewhere?  Or is it possible to build one?

At geologic timescales, yes. At human? No. If we have the tech to bring atmosphere to Mars, bring more.

As I said before, I think destroying Phobos for this purpose is a bad idea.

[acsawdey]

Mars would need a magnetic field to retain these gases? Somebody has a big magnet somewhere?  Or is it possible to build one?

At geologic timescales, yes. At human? No. If we have the tech to bring atmosphere to Mars, bring more.

Well since we are talking mega-projects, why not add one more? Just run 13,263 miles of high-Tc superconductor around Mars and make your own magnetosphere for it. Bonus feature: add extra current capacity and use it to provide constant power for settlements from 3 or more solar arrays (one will always be illuminated) (at least until the first planetary dust storm).

[Lampyridae]

Getting the resources in situ is far, far simpler. Delta V from Pluto, which is the "cheapest" source of nitrogen in dV, is 10kps to Mars.

A substantial amount of CO2 is present in the ice caps, soil and bedrock of Mars much the way groundwater is present on Earth. If all of it was liberated by baking with solar mirrors, we'd get about a 400 millibar atmosphere. Now we only need 300 millibar to walk around without a pressure suit. That could be done with solettas. But carbon dioxide's not a great breathing gas to put it mildly. All garbage. Zubrin seems to have been hopelessly optimistic as to the amount of CO2 present. We now know that there has never been a thick Martian CO2 atmosphere.

Mars' atmosphere is thickening from the release of polar CO2 as it enters a warming phase over the next few aeons. This will almost double the atmospheric pressure but still leave it far short of the magic 60 millibars Armstrong Limit.

Liberating oxygen from iron oxides: Zubrin and McKay estimate 2200 terrawatt-YEARS for each millibar of oxygen generated this way. Or, 200 years of the Earth's current energy output to add a millibar. Cracking the soil would take 24 000 years to add sufficient breathable oxygen. It would be much simpler to use photosynthesis from the released CO2.

To get photosynthesis going, you would need a millibar or two of oxygen to kick things off. That's going to have to be brute-forced somehow. Running a Sabatier reaction, reacting CO2 with H2 then cracking the water to get the H2 back is going to take at least 60 terrawatt-years of energy.

All BOTE stuff, so be warned - but it's clearly a millennia-scale project.

[ppnl]

The proposed concept is to utilize Phobos for its chemical resources and to somehow relocate them to the surface of mars.

Actually, what I’ve been thinking is to simply detonate the planet Jupiter, then use statistical mechanics to time when to detonate it so the ‘right’ resources would arrive at mars at some point.

Although Lar suggests using the Oort Cloud, this to me as too risky and time consuming.  Nobody knows if the Oort Cloud exists or what the composition as well as abundance of materials really is.

The Oort cloud is too dangerous so instead we "detonate" Jupiter...

Improbable and dangerous do not even begin to cover it.

And as for Phobos I just don't think it has any chemical resources that cannot be more easily obtained from the surface of mars. If Mars does not have it then Phobos isn't going to help.

[Lar]

(mod) There are some people who post some very wildly improbable stuff. Sometimes, but far less often, it survives. That's usually because someone replied. Far better to just report to mod.

(fan) It is extremely likely that the Oort cloud exists.

[Lampyridae]

Phoebe is quite accesible, delta V wise. The surface is composed of large amount of amorphous carbon, CO2, cyanides, tholins and other volatiles. Escape velocity from it and Saturn are negligible, and the Saturn system offers plenty of opportunity fo gravity boosts / oberth burns.

Reading the literature, it's apparent that we simply don't know how much there is on Mars in the way of volatiles, especially CO2. It could be sequestered deep in the crust, or there may never have been a high surface pressure atmosphere in the first place. To find out for sure, we would probably need actual deep coring drill rigs on Mars and that's only going to happen with a permanent manned base or colony.

[apollolanding]

Mel had it all figured out...