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#201 2008-04-19 10:53:57

Spaniard
Member
From: Spain
Registered: 2008-04-18
Posts: 59

Re: Terraforming the Moon - Your opinion, please

Some calculations

We desire a atmosphere pressure like Earth.

Source of units: Wikipedia

Pressure (p) = 101,325 Pascals
Moon surface (s)= 3.793E7 km² = 3.793E13 m²
Moon gravity (a) = 1.622 m/s²

Using gravity as reference of force (is not totally correct as atmosphere has height and not all gases is at the same force)

p=m*a/s
m=p*s/a= 101,325*3.793E13/1.622~=2,37E18 Kg

Wow... It is a lot of mass

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#202 2008-04-19 10:54:51

Midoshi
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From: Colorado
Registered: 2007-07-14
Posts: 155

Re: Terraforming the Moon - Your opinion, please

Intriguing idea, Spaniard. I'd like to run some numbers.

First let's assume we have a 1 gigawatt (thermal power) reactor, the size of a typical large powerplant. Since D-D fusion produces 12.5 MeV and 2 neutrons per reaction on average, our reactor produces 1e21 neutrons/second.

Now let's say that we shield the reactor entirely with I-127, the only bulk available form of iodine. We'll assume that all neutrons are absorbed and turn I-127 into I-128. This isn't a terrible assumption, and it provides us with optimistic results.

I-128 is unstable with a half-life of 25 minutes. It can decay into either Xe-128 or Te-128 (both stable isotopes), but prefers Xe-128 about 93% of the time. So, approximating that every neutron produces one Xe-128 atom, we are producing 1e21 xenon atoms a second.

Every millibar of xenon on the Moon requires about 1e40 atoms. That means it would take 1e19 seconds or 300 billion years for a 1 gigawatt D-D fusion reactor to produce a 1 mbar lunar atmosphere. Of course, we'd probably have more reactors than that. As an upper estimate, let's say we have one reactor per square kilometer; that's a power density comparable to the light received from the sun at Earth's orbit (!!!) and a total of about 40 million reactors. With that it would take about 8000 years to produce 1 millibar of lunar atmosphere.

Let's look at this from another angle. For 1 millibar of xenon we would need 2e15 kg of iodine. That's about 10% of all the iodine in Earth's crust. I don't know how much iodine the Moon has, but I'm guessing less than Earth.


"Everything should be made as simple as possible, but no simpler." - Albert Einstein

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#203 2008-04-19 11:53:36

Spaniard
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From: Spain
Registered: 2008-04-18
Posts: 59

Re: Terraforming the Moon - Your opinion, please

Yeah... You are right.
It's too much Iodine. I think that the fusion was not the problem in the future with a little more advancement using other fuels that generates little energy per neutron produced.

But iodine is the big problem. Altought it is more abundant that xenon, create this atmosphere requires a large amount of mass.

Ok... which alternatives we have?

Requisites:
- Heavy molecule, enough to be retained on Moon and reach 1 atmosphere of pressure
- Very stable. It must tolerate great temperature without break (at high altitude, the temperature could change a lot)
- Not a powerful greenhouse gas. We don't want another Venus
- Chemically neutral (we don't want a corrosive atmosphere)
- Enough abundance in Solar System
- As little toxic as possible

Heavy noble gases are ideal except in the abundance. sad

Another alternatives?

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#204 2008-04-19 14:14:49

Terraformer
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From: Lancashire
Registered: 2007-08-27
Posts: 2,890
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Re: Terraforming the Moon - Your opinion, please

I'd say Helium, but that's too light.

Argon? It's naturally present on the Moon, but in what quantities I don't know.


"I guarantee you that at some point, everything's going to go south on you, and you're going to say, 'This is it, this is how I end.' Now you can either accept that, or you can get to work." - Mark Watney

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#205 2008-04-20 11:50:01

Spaniard
Member
From: Spain
Registered: 2008-04-18
Posts: 59

Re: Terraforming the Moon - Your opinion, please

Perhaps the idea of iodine could be changed by bromine (more abundant that iodine) to transmute into krypton.
Is Krypton enough heavy? I'm not sure.

I think that transmutation of elements will became a valuable tool in a medium future where fusion energy will be used at a great scale.

Midoshi was right that with deuterium-deuterium we had to much energy per neutron but I sure that we will make another designs of reactors specially used for massive transmutation of elements.

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#206 2008-04-20 12:18:15

Spaniard
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From: Spain
Registered: 2008-04-18
Posts: 59

Re: Terraforming the Moon - Your opinion, please

Argon? It's naturally present on the Moon, but in what quantities I don't know.

Probably too little, but Argon is far more abundant that Xenon or Krypton (Argon could be generated by fusion while heavier elements that Iron are not).
I suppose that with argon, if is enough heavy for moon, we could recolect it in different places of the Solar System.

With viable and economic transmutation, argon abundance would be guarranteed because chlorine is abundant.

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#207 2008-04-21 07:30:21

Terraformer
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From: Lancashire
Registered: 2007-08-27
Posts: 2,890
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Re: Terraforming the Moon - Your opinion, please

Wait. *gets periodic table out and looks at it* Here are the Noble gases atomic masses.

Helium: 4 (way to light)
Neon: 20 (an oxygen molecule is heavier)
Argon: 40 (maybe, CO2 is heavier)
Krypton: 84 (no we're talking)
Xenon: 131 (if only we actually had enough)
Radon: 222 (radioactive though)
Ununoctium: N/A (should call it Unobtainium, it's that rare. Hasn't even been observed)
Though we'd have to have pretty powerful Fusion reactors to make Argon. Iron is Atomic weight 56 and only the really big stars can fuse up to it.

Different Isotopes have different properties. I we only knew what properties we needed we could find which Isotope fits.


"I guarantee you that at some point, everything's going to go south on you, and you're going to say, 'This is it, this is how I end.' Now you can either accept that, or you can get to work." - Mark Watney

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#208 2008-04-22 07:06:04

Spaniard
Member
From: Spain
Registered: 2008-04-18
Posts: 59

Re: Terraforming the Moon - Your opinion, please

Though we'd have to have pretty powerful Fusion reactors to make Argon. Iron is Atomic weight 56 and only the really big stars can fuse up to it.

Fusions over iron are endothermic. But if we use a mixture of light and heavy atoms, it could be work (for example, use multiple D+D and have some heavy atoms in the same plasma which absorbs some energy to fuse in a endothermic reaction).

But I proposed before something more easy. Transmutate using neutron radiation. Some fusions reactions generate a neutron radiation that could be used to transmutate near elements in the periodic table.
I was talking about to use fusion as neutron radiation, but other options could be feasible. Fision, use natural neutron radiation at very close position to the sun (using a great surface), etc.

We are at the infancy of nuclear energy and technology. It is like talking about big plane engines in the times of the first steam machine.
We don't have net fusion energy yet.

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#209 2008-04-22 18:45:00

Gregori
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From: Baile Atha Cliath, Eireann
Registered: 2008-01-13
Posts: 297

Re: Terraforming the Moon - Your opinion, please

Paraterraforming the Moon would be so much easier than nuclear alchemy. Its weak gravity would allow for structures much bigger than Earth. A pressurized atmosphere could be held inside geodesic domes. A lot of imports would be required for water, volatiles etc

The great thing about this approach is that it can be gradual and modular, which is much cheaper to do.

This won't happen for a very long time, so for the time being I reckon we should bore some holes using a TBM and use huge underground installations.  That should protect us from most things the solar system can throw at us up there.

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#210 2008-04-25 08:29:55

Antius
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From: Cumbria, UK
Registered: 2007-05-22
Posts: 1,003

Re: Terraforming the Moon - Your opinion, please

Maybe just a pure oxygen atmosphere and a good sized global magnetic field to contain the ions that would otherwise escape from the upper atmosphere?

Giving the moon a xenon atmosphere would take a lot more xenon that is practically available in the solar system.  I know that this thread is speculative, but I wish that people would try to think with just an ounce of practicality.

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#211 2008-04-26 05:49:54

Terraformer
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From: Lancashire
Registered: 2007-08-27
Posts: 2,890
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Re: Terraforming the Moon - Your opinion, please

Slam comets into it?


"I guarantee you that at some point, everything's going to go south on you, and you're going to say, 'This is it, this is how I end.' Now you can either accept that, or you can get to work." - Mark Watney

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#212 2008-04-26 06:07:13

JoshNH4H
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From: Pullman, WA
Registered: 2007-07-15
Posts: 2,377
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Re: Terraforming the Moon - Your opinion, please

To get what?


-Josh

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#213 2008-04-26 13:21:15

Terraformer
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From: Lancashire
Registered: 2007-08-27
Posts: 2,890
Website

Re: Terraforming the Moon - Your opinion, please

A faster spin rate. An atmosphere. The other benefits you'd get from comets.


"I guarantee you that at some point, everything's going to go south on you, and you're going to say, 'This is it, this is how I end.' Now you can either accept that, or you can get to work." - Mark Watney

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#214 2008-04-28 04:22:33

Gregori
Member
From: Baile Atha Cliath, Eireann
Registered: 2008-01-13
Posts: 297

Re: Terraforming the Moon - Your opinion, please

A faster spin rate. An atmosphere. The other benefits you'd get from comets.

That would be a really stupid waste of good comets, endangering the lives of people on Earth etc etc

I say we mine the material on the comets to provide basic supplies for colonies, like on the moon.

Humans don't actually need an entire atmosphere to survive, just enough air to breathe, produce fuel and food etc etc

Same thing with water, we don't need oceans of water - just enough to drink, for food and for industry.

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#215 2018-08-21 17:45:29

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 13,056

Re: Terraforming the Moon - Your opinion, please

Another old topic with the meantion of lunar or moon bricks time to fix the intail pages for artifact of conversions....

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#216 2018-08-21 17:56:24

louis
Member
From: UK
Registered: 2008-03-24
Posts: 3,939

Re: Terraforming the Moon - Your opinion, please

Terraforming the Moon would be an act of cultural vandalism in my view, akin to concreting over the Amazon forest, draining the Great Lakes or filling in the Colorado Valley. The silvery Moon has huge cultural significance in all nations on Earth. Let that remain the case.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#217 2018-08-22 03:45:02

Terraformer
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From: Lancashire
Registered: 2007-08-27
Posts: 2,890
Website

Re: Terraforming the Moon - Your opinion, please

More like greening the Sahara.


"I guarantee you that at some point, everything's going to go south on you, and you're going to say, 'This is it, this is how I end.' Now you can either accept that, or you can get to work." - Mark Watney

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#218 2018-08-22 14:50:22

louis
Member
From: UK
Registered: 2008-03-24
Posts: 3,939

Re: Terraforming the Moon - Your opinion, please

How about greening the dark side of the Moon? smile

Terraformer wrote:

More like greening the Sahara.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#219 2018-08-22 17:20:43

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 13,056

Re: Terraforming the Moon - Your opinion, please

While I do agree that we should not deface the look and appearance of the moon, that there must be away to do some surface dwellings as well as underground for the espansion of man.
The dark side of the moon would be the perfect place for a telescope and more..

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#220 2018-08-22 19:07:31

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 13,056

Re: Terraforming the Moon - Your opinion, please

Something else that we might remember as we look toinhabit the moon is that it will not always be there.
aHR0cDovL3d3dy5saXZlc2NpZW5jZS5jb20vaW1hZ2VzL2kvMDAwLzA4NC84Nzcvb3JpZ2luYWwvbW9vbi1mcm9tLXNwYWNlLXN0YXRpb24uanBn

https://www.seeker.com/what-if-we-lost- … 56318.html
https://www.livescience.com/55477-what- … eared.html
https://www.spaceanswers.com/solar-syst … -the-moon/

This is a good reason to go and do science to study how to not lose the moon....

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#221 2018-08-22 20:28:12

knightdepaix
Member
Registered: 2014-07-07
Posts: 130

Re: Terraforming the Moon - Your opinion, please

SpaceNut wrote:

Something else that we might remember as we look to inhabit the moon is that it will not always be there.
This is a good reason to go and do science to study how to not lose the moon....

Would that revelation be applicable to Mars?

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