Terraforming Mercury.

[daniel l.]

Is it possible to Terraform the innermost planet? Here's my idea:

You build a massive transparent disk in space, tinted to control the amount of light getting through.

Now, here's my question. How do you keep the disk in between Mercury and the sun at all times? How do you prevent it from drifting?

Also, would it really work? Or would un-healthy radiation of other kinds get around the shade and hit the planet anyway.

[SargeRho]

You might be able to build such a thing at the Mercury-Sun L1 point, and it could double as magnetic shadow-shield, protecting Mercury from radiation. The station would also need some sort of stationkeeping, it can use the solar wind for that. The same has been proposed by NASA for Mars.

 You then still have the problem of 1/3 gravity, as with Mars, an atmosphere might not be doable at all, but you can build domes, I suppose. Bring anti-asteroid laser cannons.

[PB666]

Mercury-Sun L1 (la grange point). but disk has alot of pressure due to the proximity to the sun and instability at L1 due to solar wind.

The sun is 0.28 the distance from the sun relative to Earth at its periapsis. The amount of radiation hitting Mercury is more than 13 times higher. A piece of aluminum that reflects 80% of radiation would heat to an incredible

1/2j = 0.2x5.78x10-8 * T⁴   where incoming energy is 16800 w/(sec*m²)at periapsis.  T = 923^'K. Any film that would absorb the suns heat would melt in seconds, carbon-fiber would denature. Aluminums melting point is 933.47 K, and I think aluminum would not be stable. You could decrease temperature by increasing the radiative surface area on the back side but that would significantly increase mass. It would be easier to move mercury further away from the sun.  

You can't terraform mercury, the atmosphere is to thin and it does not have enough gravity to hold an atmosphere, it is, in essence a moon orbiting the sun.

You could however live in a depression near one of Mercury's poles, it has water (ice), minerals, CO2, etc. Mercury has alot of energy for colonization. The problem is however the structure would have to be entirely enclose.

 

[ARS]

Do you want to terraform or just build a colony? If you want to build a colony, then an underground base on the pole area is most likely the best choice, since a mercurial base could be sealed to shield it's inhabitants. A surface-based infrastructure is highly exposed to extreme heat during day and extreme cold during night, necessitating a material with high tolerance against thermal expansion with large margin of hot and cold limit since the difference of temperature in mercury is extremely large. A terraforming project is unlikely to be successful since the influence of solar wind, low gravity and extreme temperature difference would causing the newly formed atmosphere to vaporize away.

Also, why mercury? Colonization process is not a simple task. You want to make sure that there's a damn good reason to do it before you land on that planet. Terraforming is also a very time and resource-consuming. Most of the celestial body that has been proposed as potential space observation or colonization usually already have a pre-existing atmosphere (such as mars or titan) or a huge potential to support life (Europe's subterranean sea). So far what I knew about mercury is it's rich in iron (we got plenty here on earth), has extreme temperature difference, along with countless impact craters.

Basically, it's like our moon on steroid

Edited November 23, 2017 by ARS

[daniel l.]

12 minutes ago, ARS said:

 Also, why mercury? Colonization process is not a simple task. You want to make sure that there's a damn good reason to do it before you land on that planet. Terraforming is also a very time and resource-consuming. Most of the celestial body that has been proposed as potential space observation or colonization usually already have a pre-existing atmosphere (such as mars or titan) or a huge potential to support life (Europe's subterranean sea). So far what I knew about mercury is it's rich in iron (we got plenty here on earth), has extreme temperature difference, along with countless impact craters.

 

Consider that, in fifty years we could be a post-scarcity society. Our vast automation will allow us to do things sheerly for fun when we once required a resource-based reason to justify doing so. When everything's free, why not? I think Mercury, terraformed, would be a fun place to live. And we could easily maintain the environment with continual maintenance over the years.

BTW, how long would it take for the environment to decay if maintenance ceased?

Edited November 23, 2017 by daniel l.
removed 'exactly' as we tend to take it literally. :P

[electricpants]

31 minutes ago, PB666 said:

it does not have enough gravity to hold an atmosphere

Ok, hang on.

That's a huge misconception based on most moons and Mars having thin or no atmospheres.

Mars could easily have an Earth-like atmosphere if it had a magnetic field to block the solar wind from depleting it, same with Mercury, as they both have around the same gravity.

They both easily have enough gravity to hold onto an atmosphere thick enough to support surface water, it's just that they don't actually have substantial magnetic fields themselves.

In fact, Mars's atmosphere is only slightly under the lower limit (In terms of atmospheric pressure) where water could exist, so that's actually pretty substantial for our solar system.

However, I do think gravity has at least some factor, as it is highly unrealistic to have an asteroid have an atmosphere, mainly because if the gravity is too low to hold on to the constantly vibrating molecules that make up atmospheres then they won't have one, but Mars, the moon, and Mercury all have enough gravity (I'm only pretty sure for the moon though, because it's gravity is only 1/16 of Earth's)

Edited November 23, 2017 by electricpants

[ARS]

If what you mean the maintenance on the mercury base, then the only limit is the strength of the base itself. Once maintenance ceased, thermal expansion will work it's way on the structural integrity of the base before the base collapses (depends on what material you use) and for the orbital disk, it depends on how long they can maintain their orbit. Space is not as empty as you think, since even a small particle could induce a drag that makes slight change on the satellite orbit which makes a stationkeeping a necessity by providing satellites with limited propulsion to maintain orbit. Usually a satellite's life ends when the on-board fuel has been entirely expended. With a huge shield orbiting the mercury, the drag would be enormous (hell, you could say it is a solar sail instead of a shield). Once maintenance has ceased, it's only a matter of time before it crashed

As for maintenance of earth's environment, there's a saying that no matter how we destroy the environment, the nature will always come to take it back, but the human... not so much. Take a look at Chernobyl disaster, the area becomes uninhabitable for humans for several thousand years, yet vegetation and animals is already coming back. The best maintenance for nature is by not messing with it in the first place

[daniel l.]

32 minutes ago, ARS said:

As for maintenance of earth's environment, there's a saying that no matter how we destroy the environment, the nature will always come to take it back, but the human... not so much. Take a look at Chernobyl disaster, the area becomes uninhabitable for humans for several thousand years, yet vegetation and animals is already coming back. The best maintenance for nature is by not messing with it in the first place

I actually meant the environment of a terraformed Mercury.

[ARS]

28 minutes ago, daniel l. said:

I actually meant the environment of a terraformed Mercury.

Even with terraforming, mercury's magnetic field is still too weak to shield from solar radiation, and it's close proximity to the sun creates a temperature difference far more deadly than what happen on earth, even if there's an atmosphere. No plants can survive on it's surface. The best that you can do is building an underground habitat with "glass panels" on the roof (with filter of course) to facilitate plant's photosynthesis to generate oxygen. Assuming no maintenance being performed, then the base's structural integrity will start decaying due to the stress on metal parts caused by thermal shock of temperature difference. At that point, it's only a matter of time before there's a crack, the heat from the outside gets in and destroying inner sections of the base

[daniel l.]

3 minutes ago, ARS said:

Even with terraforming, mercury's magnetic field is still too weak to shield from solar radiation, and it's close proximity to the sun creates a temperature difference far more deadly than what happen on earth, even if there's an atmosphere. No plants can survive on it's surface. The best that you can do is building an underground habitat with "glass panels" on the roof (with filter of course) to facilitate plant's photosynthesis to generate oxygen. Assuming no maintenance being performed, then the base's structural integrity will start decaying due to the stress on metal parts caused by thermal shock of temperature difference. At that point, it's only a matter of time before there's a crack, the heat from the outside gets in and destroying inner sections of the base

5

Well, sounds like Mercury could make for a perfect barely-habitable desert planet. Searing days, frigid nights. Atmospheric oxygen generated through artificial-photosynthesis machines.

[ARS]

Mercury is a planet of massive extremes: The surface temperature of Mercury ranges from 700 K (the side facing the sun, it's incredibly hot), but the side facing away from the sun is incredibly cold, up to -200 degrees. Since the planet's atmosphere can't hold or convect any significant amount of heat, anything in shadow is very cold. How cold? There's ice in the nooks and crannies of the planet where the Sun doesn't shine. It's still not livable by any means, but it makes the planet far more interesting to astronomers. Currently, Mercury is not a priority on any space program worldwide. It’s farther away than Mars, hotter and less hospitable as well less likely to contain evidence of life. Still, this planet has a lot to teach us about the extremes of planetary science — which in turn has a lot to teach us about the search for life elsewhere in the universe. The only far more extreme planet is either Venus or Jupiter's moon, Io

Edited November 24, 2017 by ARS

[daniel l.]

4 hours ago, ARS said:

Mercury is a planet of massive extremes: The surface temperature of Mercury ranges from 700 K (the side facing the sun, it's incredibly hot), but the side facing away from the sun is incredibly cold, up to -200 degrees. Since the planet's atmosphere can't hold or convect any significant amount of heat, anything in shadow is very cold. How cold? There's ice in the nooks and crannies of the planet where the Sun doesn't shine. It's still not livable by any means, but it makes the planet far more interesting to astronomers. Currently, Mercury is not a priority on any space program worldwide. It’s farther away than Mars, hotter and less hospitable as well less likely to contain evidence of life. Still, this planet has a lot to teach us about the extremes of planetary science — which in turn has a lot to teach us about the search for life elsewhere in the universe. The only far more extreme planet is either Venus or Jupiter's moon, Io

Still, if a shade was built that could block most of the sunlight, reducing intensity to the levels we get on Earth. They daylit-side would be much cooler. I'm also suggesting thickening the atmosphere to 1 Bar, like Earth's, an atmosphere would allow that heat to convect far enough into the night-side to keep it pseudo-habitable, though not pleasant -- like Antarctica.

[ARS]

9 minutes ago, daniel l. said:

Still, if a shade was built that could block most of the sunlight, reducing intensity to the levels we get on Earth. They daylit-side would be much cooler. I'm also suggesting thickening the atmosphere to 1 Bar, like Earth's, an atmosphere would allow that heat to convect far enough into the night-side to keep it pseudo-habitable, though not pleasant -- like Antarctica.

Thickening the atmosphere requires stronger magnetic field of the planet itself in order to maintain it. With current mercury's magnetic field, it's far too weak to prevent atmospheric gases to vaporized away by the sun (mercury is the smallest planet in our solar system anyway, so it's not a surprise that it has a fairly weak magnetic field). What needs to be done first is by finding a way to prevent that (or you could just dig underground base, which is far more easier than terraform a whole planet). We also haven't deal with radiation problem. On earth, harmful radiation from the sun is filtered by ozone layer, but on mercury... With no ozone layer or atmosphere, not to mention being the closest to the sun, you can imagine how insane the solar radiation that the colony takes per day

Judging from current condition of mercury, here's what we had to do (somehow) to terrarform it:

1-fix magnetic field so it can hold atmosphere

2-make an atmosphere (thick enough to shield from direct exposure, radiation and heat, but without greenhouse effect like venus) or just make an orbital shield like you suggest

3-somehow find a way to make power from non-solar source (thick atmosphere prevents it)

4-build a habitat

If you just want a base there, skip part 1,2,3 and just go straight to part 4

[NSEP]

I think a dome on a crater with everything in the crater, maybe with a gaint mirror to regulate sunlight is a way to terraform a little bit of Mercury. I don't know about full on terraforming though.

[MatterBeam]

Oh it's certainly possible. You'd need tremendous amounts of energy.

The first thing to do is unlock the nitrogen and oxygen locked in the planet's minerals. Earth's crust should not be terribly different from that of Mercury, so you can expect nearly half of every kg of rock to be oxygen. You'd then import nitrogen from other sources in the Solar System, such as Titan. You'd need  a 2.6 times thicker atmosphere to create 1atm on the ground. You will have to do this continuously too. Earth loses about 90 tons of atmosphere every day. At the same temperature but with a 0.38g gravity, you'd lose 236 tons per day. 

To protect Mercury, you'd need a strong magnetic field. Mercury is a 17.8 times smaller volume to cover with a magnetic field than Earth, but it is 13 times closer to the Sun. So, you need to generate a magnetic field about 38% stronger than that of Earth. 

Then, you'd need to handle the sunlight. 

On one side, you need to reflect away 92% of the incoming sunlight. The hard way to do it is to create a very transparent filter with a high refractive index, that you stack until 92% of the sunlight bounces away and 8% goes through, while nearly nothing is absorbed by the filter itself. It might look like a Bragg (dielectric) reflector and made of quartz. The easy way is to create billions of small rotating shutters that open up 8% of the time. It'll look terrible and give you a headache though. 

That should be enough. 

A barren, dry world where you slowly die of microgravity sickness while the light blinks like a badly tuned fluorescent line above, but hey, at least you can take your helmet off!

[PB666]

1 minute ago, MatterBeam said:

Oh it's certainly possible. You'd need tremendous amounts of energy.

The first thing to do is unlock the nitrogen and oxygen locked in the planet's minerals. Earth's crust should not be terribly different from that of Mercury, so you can expect nearly half of every kg of rock to be oxygen. You'd then import nitrogen from other sources in the Solar System, such as Titan. You'd need  a 2.6 times thicker atmosphere to create 1atm on the ground. You will have to do this continuously too. Earth loses about 90 tons of atmosphere every day. At the same temperature but with a 0.38g gravity, you'd lose 236 tons per day. 

To protect Mercury, you'd need a strong magnetic field. Mercury is a 17.8 times smaller volume to cover with a magnetic field than Earth, but it is 13 times closer to the Sun. So, you need to generate a magnetic field about 38% stronger than that of Earth. 

Then, you'd need to handle the sunlight. 

On one side, you need to reflect away 92% of the incoming sunlight. The hard way to do it is to create a very transparent filter with a high refractive index, that you stack until 92% of the sunlight bounces away and 8% goes through, while nearly nothing is absorbed by the filter itself. It might look like a Bragg (dielectric) reflector and made of quartz. The easy way is to create billions of small rotating shutters that open up 8% of the time. It'll look terrible and give you a headache though. 

That should be enough. 

A barren, dry world where you slowly die of microgravity sickness while the light blinks like a badly tuned fluorescent line above, but hey, at least you can take your helmet off!

There is less nitrogen and oxygen locked in Mercurial rock than on Mars and the outer planets. The albedo of Mercury and its proximity to the sun has forced the conversion of metal oxides into metals and oxygen free radicals that boil off and leave the atmosphere. The water you see on mercury's dark crater is the reaction of these oxides with the suns proton plasma (in solar flares) as the hydrogen streams around the light termination of the planet. Don't expect to find much oxygen until you did 100s of meters deep.

It is not possible to terraform mercury . . . .life is not Spore, there is no god-mode terraforming tool.

" Mercury is much smaller and its inner regions are not as compressed. Therefore, for it to have such a high density, its core must be large and rich in iron." wikipedia.

Earths mantle-crust is thicker because it is loaded with oxides, sulfates and carbonates.

"Mercury's surface composition is very different from that of other planets in the solar system. It is dominated by minerals high in magnesium and enriched in sulfur. This composition is similar to that expected from partial melts of enstatite chondrites, a rare type of meteorite that formed at high temperatures in highly reducing (low oxygen) conditions in the inner solar system." -https://phys.org/news/2012-09-characterizing-surface-composition-mercury.html#jCp

MgCO3 --(heat)---> MgO + CO2(gas) ----(heat)---> Mg + O*(reactive free radical)
You might, if you are very lucky, find calcium oxide on the surface.

MgSO4 -(heat)--->MgS + 4O*

Free magnesium is great for you ION drives, but its going to strip oxygen and carbonate off of anything that bears them in mercury's soil.

[MatterBeam]

24 minutes ago, PB666 said:

There is less nitrogen and oxygen locked in Mercurial rock than on Mars and the outer planets. The albedo of Mercury and its proximity to the sun has forced the conversion of metal oxides into metals and oxygen free radicals that boil off and leave the atmosphere. The water you see on mercury's dark crater is the reaction of these oxides with the suns proton plasma (in solar flares) as the hydrogen streams around the light termination of the planet. Don't expect to find much oxygen until you did 100s of meters deep.

It is not possible to terraform mercury . . . .life is not Spore, there is no god-mode terraforming tool.

" Mercury is much smaller and its inner regions are not as compressed. Therefore, for it to have such a high density, its core must be large and rich in iron." wikipedia.

Earths mantle-crust is thicker because it is loaded with oxides, sulfates and carbonates.

"Mercury's surface composition is very different from that of other planets in the solar system. It is dominated by minerals high in magnesium and enriched in sulfur. This composition is similar to that expected from partial melts of enstatite chondrites, a rare type of meteorite that formed at high temperatures in highly reducing (low oxygen) conditions in the inner solar system." -https://phys.org/news/2012-09-characterizing-surface-composition-mercury.html#jCp

MgCO3 --(heat)---> MgO + CO2(gas) ----(heat)---> Mg + O*(reactive free radical)
You might, if you are very lucky, find calcium oxide on the surface.

MgSO4 -(heat)--->MgS + 4O*

Free magnesium is great for you ION drives, but its going to strip oxygen and carbonate off of anything that bears them in mercury's soil.

I mentioned importing Nitrogen from elsewhere. 
It costs less in terms of kJ/kg to extract oxygen from Mercury's crust than to ship it in from other planets. 
If you've got a plan to create a magnetic field stronger than Earth, and move thousands of tons of material and equipment from other planets to Mars, then digging  a bit deeper to get oxidizer metals is trivial.How does sunlight ionize metals underneath the surface anyway, let alone 100m deep anyway?
It is possible to terraform Mercury. You just need a lot of energy.
There is vastly more oxygen than necessary, locked up in metal oxides on Mercury, than is needed to create a thick atmosphere on Mercury. 
A rough estimate puts 300km/2440km:~12% of Mercury's mass in the crust. That's 4e22kg of crust. Earth's atmosphere is contains 1.2e18kg. We need 2.6 times more for Mercury's atmosphere, so 3.12e18kg. 
Therefore, you only need the crust to contain 0.078% oxygen by mass to fulfil your needs. You'll find the actual fraction to be closer to 40%+.