Terraforming the Moon - Your opinion, please

RobertDyck · 2007-07-06 18:14:16

I would say terraforming the Moon is not a good idea. Never mind whether it can be done, it shouldn't be done. This is an airless world very close to the Earth, a highly developed settled planet with a giant thriving economy and a diverse biosphere. The Moon is needed for industrial processes that require vacuum and partial gravity, as well as interferometry telescopes that can image Earth size planets around other stars.
But Earth is deep within a gravity well, and the vacuum and viewing conditions are better at L5. A terraformed moon would make a great base for exploiting the rest of the solar system.

Interferometry requires coordinating several telescopes, typically 4, so that each telescope has a precise distance from the others. It has to be so controlled the distance is within a fraction of a wavelength of light. We can't do that with orbital structures, the vibrations are many wavelengths in amplitude so they destroy any interferometry effect. Notice the key word: interferometry, meaning you measure the interference. The point is to get waves of light from one telescope to cancel the waves of light from another for a focussed object. Then you can cancel the light from a star so you can see light from near, faint objects like planets orbitting that star. We can do that on Earth with a multi-ton block of rock or concrete, but the atmosphere is like a thick soup that is constantly fluctuating with waves. You can't see anything as small and faint as a planet through our atmosphere. However, we can build an interferometry telescope on a big block of rock on the Moon. No air, no vibration, multi-ton foundation: everything we need. That will enable us to image Earth like planets around other stars. But if you put an atmosphere around the Moon, you create the same problem as Earth.

Second, the Moon has very low gravity (shallow gravity well) so you can launch objects into space. It also has vacuum that can be utilized for industrial processes. The bottom line is you need the vacuum, putting an atmosphere round it would destroy it.

Third thing: you can use the atmosphere of Earth to get out of the gavity well. An air-breathing hypersonic aircraft can get you most of the way to orbit. NASA just announced its latest research opportunity in aeronautics. It includes hypersonics, developing an air-breathing engine and integrated air frame to fly in the hyperspeed regime. They came up with a new name; previously subsonic meant less than the speed of sound, transonic means crossing the speed of sound, supersonic means faster than the speed of sound up to mach 5, and hypersonic meant faster than mach 5. Now they've subdivided hypersonic, the new definition is hypersonic goes form mach 5 to mach 10; hyperspeed is mach 10 to mach 18. This research opporunity is for hyperspeed. Note: the Space Shuttle enters the atmosphere at mach 25, so mach 18 is most of the speed required. If you only need a LOX/LH2 rocket for the final push from mach 18 to mach 25 then your fuel tank will be very small. They're on the way to a true spaceplane.

Assuming they succeed, getting out of the gravity well to LEO won't be hard. The spaceplane will not be optimized for space travel, all those wings and air control surfaces and air-breathing engines and heat shields and landing wheels are completely useless in space. That means the spaceplane will only get you to LEO, another spacecraft will transfer to higher orbit or the Moon. I envision space tourism to the Moon with a lay-over in LEO, probably the same altitude as ISS.

noosfractal · 2007-07-22 00:40:09

Thinking about maintaining a Lunar atmosphere, I wanted to work out loss rates - you're going to lose some, but how much, how fast?

From what I read, Jeans escape flux gives reasonable results. The main parameters are the exobase height and temperature. To simplify, I assumed an all-oxygen atmosphere (say, generated by heating lunar regolith), and an exobase height that basically scales from Earth's (e.g., 500 km * 100 mbars / 1000 mbars * 9.8 / 1.6 = 300 km for a 100 mbar atmosphere). Earth's exobase temperature varies from 1000 K (solar min) to 2500 K (solar max) mostly due to oxygen absorption of far UV[1]. I assumed the same for an atmosphered Luna, with an average value of 1500 K.

That gives the flux as a function of surface pressure, and the surface through which the flux flows is just the sphere with radius = radius_luna + exobase_height. The exobase height has a big influence because it increases the size of the sphere, but also decreases the gravitational attraction keeping the gas close to Luna ...

surface pressure (mbar) -- mass loss per year (million tonnes) -- GW

100 -- 53 -- 300
170 -- 81 -- 460
200 -- 95 -- 540
400 -- 230 -- 1300
700 -- 540 -- 3100
1000 -- 1000 -- 5800

The last figure (GW) is how much power is required to generate the mass of oxygen lost per year from lunar regolith at 50 kWh/kg (estimates range from 20-50 kWh/kg [2]). The 460 GW figure to maintain 170 mbar is about what the US generated in 2004[3].

Zubrin's calc's for a 10 billion tonne iceteroid calls for 20 GW and a 75 year transit time to collide with Mars[4]. If we assume 50 GW and 150 years, the same asteroid can be safely orbiting Luna. It would provide replenishment needs for ~120 years at the 170 mbar level.

None of this assumes an artificial magnetosphere (although exobase may be higher without a magnetosphere) or cooling of the exobase. However, anything that can be done to cool the exobase helps tremendously. For example dropping the exobase temperature to 1000 K drops the power requirements to 125 GW for the 170 mbar case.

[1] http://www.geosc.psu.edu/~kasting/Abiol … escape.ppt
[2] http://fti.neep.wisc.edu/neep602/LEC20/IMAGES/fig21.GIF
[3] https://www.cia.gov/library/publication … os/us.html
[4] http://www.users.globalnet.co.uk/~mfogg/zubrin.htm

*** EDIT

(Figures adjusted again, 3rd time lucky).

Note that the power requirements can be dropped an order of magnitude if you are just electrolyzing water (e.g., from an iceteroid), so that it would require 46 GW for the 170 mbar case.

noosfractal · 2007-07-22 01:32:06

Interferometry requires coordinating several telescopes, typically 4, so that each telescope has a precise distance from the others. It has to be so controlled the distance is within a fraction of a wavelength of light. We can't do that with orbital structures, the vibrations are many wavelengths in amplitude so they destroy any interferometry effect. Notice the key word: interferometry, meaning you measure the interference. The point is to get waves of light from one telescope to cancel the waves of light from another for a focussed object. Then you can cancel the light from a star so you can see light from near, faint objects like planets orbitting that star. We can do that on Earth with a multi-ton block of rock or concrete, but the atmosphere is like a thick soup that is constantly fluctuating with waves. You can't see anything as small and faint as a planet through our atmosphere. However, we can build an interferometry telescope on a big block of rock on the Moon. No air, no vibration, multi-ton foundation: everything we need.

I'm familiar with interferometry, and you are mistaken here. It is impossible for large structures to be placed with nanometer precision. Even if it were, heating and cooling of the foundation would change the distance over the course of 24 hours. In practice, each set of telescopes is either linked with optical fiber or does clever things with synchronized atomic clocks ( see http://en.wikipedia.org/wiki/Very_Long_ … rferometry ).

There are constant vibrations and even moonquakes ( http://science.nasa.gov/headlines/y2006 … quakes.htm ) on Luna generated by tidal forces. Any space structure would have less vibration, but even better, huge arrays of space telescopes can (and likely will) be built that are connected only with synchronizing lasers.

I've seen people claim that Luna astronomy could be much cheaper than L2-based systems, but they usually assume manned Luna bases which is hardly a given at this point.

RobertDyck · 2007-07-22 09:04:35

It's amazing what you can do with something as simple as a leaver and set-screw. One experiment in grade 11 physics was to shine a hand-held laser through a pair of glass microscope slides. One end of the slides touched, the other had a piece of paper between the slides, and an elastic band held them together. Room lights were turned off and curtains over the windows so the room was dim, but you could see. We shined the laser through the glass with a piece of white paper on the table beneath it. You could see interference bands. It worked because the laser produced exactly one frequency of light. For the experiment we counted the number of bands, the paper was that many wavelengths of light thick. Multiply by the wavelength of the laser to get paper thickness in micrometres. I noticed when I pushed on the glass with my finger I could see the interference bands move; that was due to the glass flexing, the light interference bands were that sensitive.

If I can adjust a light interference band with my finger using nothing but a glass slide, rubber band, and my finger, imagine what can be done with a titanium set screw.

noosfractal · 2007-07-28 23:07:54

Thinking about maintaining a Lunar atmosphere, I wanted to work out loss rates - you're going to lose some, but how much, how fast?

The figures in the above quoted post assume an exobase temperature of 1500 K, but as I mentioned in another thread it seems that having a percentage of CO2 in your atmosphere yields a low exobase temperature (see Mars, Venus). You'd still need a mask to breath the atmosphere, but pressure and temperature could be earth normal. Dropping the exobase temperature even moderately has a substantial effect ...

exobase temp. (K) --- oxygen loss rate (megatonnes/yr) --- Replace Power

1500 --- 81 --- 460 GW
1300 --- 54 --- 310 GW
1100 --- 31 --- 180 GW
900 --- 14 --- 80 GW
700 --- 4 --- 23 GW
500 --- 0.4 --- 2.2 GW
300 --- 0.001 --- 9.4 MW

An exobase temperature of 300 K would probably require > 90% CO2, but 500 K may be achievable with just 50% CO2. 1100 K can probably be achieved with < 1% CO2.

CO2 production is exothermic once you have the oxygen. Lunar oxygen production would still have you in deficit, but it could still be used to offset some of the atmosphere maintenance power requirements.

There are known methods to cut the power requirements in half, and you can divide by 10 if you can just use electrolysis of water (e.g., from an iceteroid). You'll need a C-type asteroid for the carbon.

Antius · 2007-07-31 07:21:40

The alternative to natural terraforming is paraterraforming, ie, covering the surface in giant greenhouses. The biosphere would consist of thousands of small glass cells, interlinked by sub-lunar tunnels. In the event that a meteorite strike takes out an individual cell, the tunnels connecting to the cell will be sealed until it can be repaired and repressurised.

Paraterraforming the moon offers a number of advantages:

1) The amount of gas needed is smaller and altogether more achievable;
2) The process can take place incrementally - small investments gradually building up to a fully terraformed world, but habitable from day one;
3) The glass needed can be produced from abundant lunar anorthite and the oxygen making up 90% of the atmosphere and mass of water, can be produced from lunar ilmenite.
4) Paraterraforming would leave unterraformed areas of the moon in vacuum, which allows mass drivers to continue operating. This is likley to be the moon's primary source of export revenue.

atitarev · 2007-09-10 19:08:29

I am a rare visitor here but I support the idea of paraterraforming.

I also think that Luna with a non-breathable but sustainable atmosphere is better than no atmosphere for a number of reasons:

Landing and working on the Moon would be much easier and safer. Perhaps some plants could be adjusted to the atmosphere, so the new world is not that boring.

sonjz · 2007-10-17 02:44:57

I enjoyed the discussion on this board. I'm also interested in the idea of terraforming the moon... more as a common goal for humans to focus on that we can all equally share seeing the progress in... it is after all visible most nights. Much better than building newer stealth bombers..

sonjz · 2007-10-17 02:45:23

If you're interested in raising the numbers of a facebook group I started feel free to join, I think letting more people believe it's plausible will bring more awareness and support, like the Google Lunar X project:

http://www.facebook.com/group.php?gid=5235549707

Regards,
Jay.

Tom Kalbfus · 2007-10-17 22:39:40

I enjoyed the discussion on this board. I'm also interested in the idea of terraforming the moon... more as a common goal for humans to focus on that we can all equally share seeing the progress in... it is after all visible most nights. Much better than building newer stealth bombers..

In leiu of terrafroming a Moon, you might want to consider building these size O'Neill colonies:

O’Neill Colonies
Island Three Dimensions Acceleration = 9.81 m/sec
Radius = 3.218688 km Length = 32.18688 km rVelocity = 177.604 m/sec T = 113.869 sec
Radius = 6.437376 km Length = 64.37376 km rVelocity = 251.170 m/sec T = 161.035 sec
Radius = 12.87475 km Length = 128.7475 km rVelocity = 355.208 m/sec T = 227.738 sec
Radius = 25.74950 km Length = 257.4950 km rVelocity = 502.340 m/sec T = 322.071 sec
Radius = 51.49901 km Length = 514.9901 km rVelocity = 710.416 m/sec T = 455.477 sec
Radius = 102.9980 km Length = 1,029.980 km rVelocity = 1,004.68 m/sec T = 644.141 sec
Radius = 205.9960 km Length = 2,059.960 km rVelocity = 1,420.83 m/sec T = 910.954 sec
Radius = 411.9921 km Length = 4,119.921 km rVelocity = 2,009.36 m/sec T = 1,288.28 sec
Radius = 823.9841 km Length = 8,239.841 km rVelocity = 2,841.66 m/sec T = 1,821.91 sec
Radius = 1,647.968 km Length = 16,479.68 km rVelocity = 4,018.71 m/sec T = 2576.57 sec

With carbon nanotubes, or carbon composites, you can build the largest of these colonies which approach the size of a moon, they also have the advantage of an Earth-normal gravity and less air leakage.

akkakappa · 2007-10-24 04:29:41

hello everybody,

I would appreciate to know your opinion about creating a lunar atmosphere bombarding the moon with regolith rocks launched at high speed by a robotic catapult or mass driver from the lunar surface to another far dark cold point on the moon surface (probably the dark sides or better the poles).

The low gravity of the moon supports the high speed launch of the regolith and the very high-speed impact with the surface would melt the rocks and free oxygen and other gases from the surface.

The low temperature of the target point would eventually help to slow the gas molecules escaping.

This process would not involve use of heavy atomic bombs or asteroid, instead would be a continous bombardment with a simple robotic system.

your opinion would be very appreciated,

thank you,

akkakappa

cIclops · 2007-10-24 06:00:37

hello everybody,
I would appreciate to know your opinion about creating a lunar atmosphere bombarding the moon with regolith rocks launched at high speed by a robotic catapult or mass driver from the lunar surface to another far dark cold point on the moon surface (probably the dark sides or better the poles).

Ciao akkakappa!

As the catapult process requires the conversion of electrical energy into mechanical energy and then into kinetic energy and that the corresponding impact process is highly wasteful of that energy, it would be more efficient to use the electrical power directly to melt the rocks.

akkakappa · 2007-10-24 06:16:41

In terms of Efficiency you are right.

But don't you think that direct electrical melting would produce much less gas so that you need a huge industrial facility to sustain a continous gas production?

I think there are a lot of good methods (example solar forge), but we must consider the escape speed of the produced gases.

thank you, good analysis

akkakappa

Antius · 2007-10-30 02:48:57

In terms of Efficiency you are right.
But don't you think that direct electrical melting would produce much less gas so that you need a huge industrial facility to sustain a continous gas production?
I think there are a lot of good methods (example solar forge), but we must consider the escape speed of the produced gases.
thank you, good analysis
akkakappa

Some sort of magma electrolysis may turn out to be easier. At the sort of impact speeds neccesary for mass driver derived oxygen production, much of the gas would have a free-path speed that exceeded escape velocity. As soon as a significant atmosphere began to accumulate, the operation of the mass driver would be impeded.

Magma electrolysis would occur on a large scale anyway, as soon as large scale manufcature of metals were carried out by lunar colonists on the surfcae of the moon. Because the molten magma contains metals and is itself conductive, there is potential to avoid the need for expensive electrodes.

Orionite · 2008-01-01 18:55:48

Much discussion has already taken place on the problem of gas retention in an artificial lunar atmosphere. But has anyone else brought up the possibility of departing substantially from earth's atmosphere to develop a breathable mix from oxygen and noble gases?

Nitrogen has a molecular mass of approximately 28 AMU. Some of the work discussed earlier in this thread points out that an atmosphere of oxygen and nitrogen might last only a few hundred years. The noble gas Xenon has an atomic mass of 131. Mixtures of noble gases and oxygen are used in SCUBA equipment for deeper dives, where nitrogen gas can cause narcolepsy and the "bends".

noosfractal · 2008-01-02 01:43:14

Hi Orionite, welcome to newmars.

Xenon?

Good thought, but where are you going to get enough Xenon?

qraal · 2008-01-18 05:13:04

Hi All

Since there's negligible xenon around for making atmospheres let's use sulphur dioxide since we know there's both elements on the Moon, and it would be a "natural" pollutant from using Brimstone+LOX rockets. Its molecular mass is 64, which is better than oxygen, and it freezes at 200 K so it might be effectively "cold trapped" at night.

Terraformer · 2008-01-18 14:06:59

Sulpher Dioxide?!?! I thought we were talking atmospheres for breahing, not just braking. You really want to be breathing that in?

Argon? It makes up most of the present atmosphere and is being constantly replenished by the internal workings of the moon.

qraal · 2008-01-18 18:21:25

Hi Terraformer

I don't want to breathe SO2 but it's available, and it'll be a pollutant from rockets using indigenous fuels - the other options being powdered aluminium or iron in LOX. It might be useful for an initial atmosphere until we work out an easier way of cracking oxygen out of the rocks.

Sulpher Dioxide?!?! I thought we were talking atmospheres for breahing, not just braking. You really want to be breathing that in?

I didn't think there was much potassium in the Moon for argon to be belched by lunar vulcanism.

Argon? It makes up most of the present atmosphere and is being constantly replenished by the internal workings of the moon.

Of course Stephen Baxter (and Poul Anderson before him) could be right and there's lots of water-of-hydration in the deep mantle. Perhaps we can get the Moon to belch it up, along with assorted gases like SO2, N2 perhaps. Current "Big Splat" simulations don't have enough resolution to say whether the Moon formed purely out of rock vapour or out of intact mantle chunks, so there's a chance there's water down there.

Midoshi · 2008-01-18 21:43:36

Hmm, it's true that sulfur dioxide is both a heavy molecule and a "cold trap" candidate. Unfortunately it's extremely toxic: breathing it at concentrations as low as a few hundred ppm will kill you in a few minutes.

But it's a bit more serious than that (if you can believe it). Sulfur dioxide + sunlight + water = sulfuric acid. You know how your eyes feel when you cut onions? That's sulfuric acid in your eye from the breakdown of sulfurous vapors drifting off the onion...I'd hate to be in an atmosphere with large amounts of that in it. You'd have acid rain eating through your house, your clothes, your skin...ouch!

However, I will give you kudos for thinking outside the box, qraal. Just keep thinking "crazy" thoughts and eventually one of them will work! (:

At least, that what I keep telling myself...

qraal · 2008-01-18 22:23:56

Hi midoshi

Of course the stuff is toxic, but my main idea was for rocket exhausts to add atmosphere to the Moon. Eventually we'd learn how to make oxygen out of the rocks and/or wring water out of the deep mantle, but for a temporary atmosphere that would stick around SO2 seemed a good idea.

Terraformer · 2008-01-19 04:54:06

But if it freezes, what's the point? You'd keep getting your base covered in frozen gasses which would then thaw out, Rinse, and repeat.

atitarev · 2008-01-29 18:55:33

Much discussion has already taken place on the problem of gas retention in an artificial lunar atmosphere. But has anyone else brought up the possibility of departing substantially from earth's atmosphere to develop a breathable mix from oxygen and noble gases?
Nitrogen has a molecular mass of approximately 28 AMU. Some of the work discussed earlier in this thread points out that an atmosphere of oxygen and nitrogen might last only a few hundred years. The noble gas Xenon has an atomic mass of 131. Mixtures of noble gases and oxygen are used in SCUBA equipment for deeper dives, where nitrogen gas can cause narcolepsy and the "bends".

Excellent idea!

Let's worry about where to get it from later, I am sure there will be a method (just ask Karov ). Doesn't that prove the Moon can theoretically be terraformed? Well, it has been proved many times by optimists but this time it seems far more realistic even from a skepticist's point of view.

(I am the topic starter but I seldom post now).

qraal · 2008-02-01 05:30:05

Where are you going to get enough Xenon from?

I'm really dubious about the claim that the Moon's atmosphere would escape in just a few centuries - that just doesn't seem right. How? One atmosphere pressure on the Moon would need an air column mass of ~ 62,500 kg/sq.metre - if all the sunlight hitting the Moon went into launch the air into space some 16 years worth would be needed at 100% efficiency - which wouldn't happen. To happen in just 200 years would need 8% efficiency of energy-into-atmosphere - which also seems a tall ask. Earth's mesosphere doesn't absorb that much energy, no way, so I very much doubt the Moon's would.

Another issue is water loss. Dehydrating the Moon takes energy - lots of energy. Busting apart hydrogen from water (H2O -> H + OH) takes 15.63 MJ/kg - a 1,000 metres of water on the surface would need 1,450 years of all the Sun's energy that hits the Moon to just dissociate. But since the high energy end of the solar spectrum is needed (just 6% of the total) that time extends to >24,000 years at 100% efficiency. The stratospheric cold trap would work as well on the Moon as on Earth - if not better - so the actual loss time would be much higher.

samy · 2008-02-16 15:43:43

Also, if the buffer gas atomic mass is much higher than oxygen, then won't it displace the oxygen, like a heavier liquid sinks to the bottom of the glass? Thus completely depriving the surface of oxygen.

Nitrogen is roughly the same as oxygen, so it doesn't displace the oxygen and the two mix at the surface. But if we had some really heavy buffer gas, it would create pressure, sure, but it would also separate all the oxygen away from the surface.

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