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Likewise, the global composition of the moon is irrelevant to this discussion. By that logic I have news for you: the Earth's crust has a poor abundance of precious and heavy metals! Too bad we can't extract the resources we need from it.
We're talking about locally concentrated ores and volatile deposits, and the mechanisms which might create and/or protect them on or near the lunar surface. Due to vast differences in geology, impactor speed, and weathering, those mechanisms will be different than on Earth.
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JonClarke wrote:Only in the metallic form. Not when it is locked up in silicates.
Mercury locked up in silicates? Cite? So as I know it occurs as a native metal or as HgS.
For accumulations of Hg this is correct. But where do you think those accumulations fome from? From tiny amounts(10s to 100s ppb) in silciates (and in some sulphides, if present. These can be stripped by hydrothermal fluids to form the concentrations we called deposits, generally requiring enrichment factors of at least a hundred. I suggest you consult any one of the standard references of the subjct - "Handbook of geochemistry", "Planetary scientist's companion", "Field Geologist's Manual" etc. for details of Hg distribution in rocks and minerals.
And lunar rocks have very low Hg - less than 0.3 parts per billion. That is less than 1% of the average abunance in terrestrial crust.
You heat cinnabar and the mercury vapor separates out. Given that the lower lunar latitudes get quite hot and it's vacuum, you'd expect the Mercury vapor to be baked out of the lunar crust.
Correct, but when the Hg does not occur as a separate phase, the temperagtures are much higher.
Lunar Hg in returned samples occurs in three ways (at least), a labile phase, which can be mobilised at temperatures of <140 degrees, a less labile phase, bolised at higher temperatures but still below 450 degrees, and a high temperature phase, liberated at temperatures above 450 degrees. The total about is low, a few ppb typically - occasionally a few 10s of ppb. The proportions vary markedly from sample to sample and location to location. the most labile phase is probably ultra thin metallic Hg that probably does move round with the diurnal cycle. The less labile phase is probably reacted on coatings, and the high temperature phase occurs in silicates and probably troilite (iron sulphide).
Some of the most labile phase does end up in the lunar atmosphere, but how far it travels is anybody's guess. Given the untrustworthiness of the LCROSS data in this regard it would be specious to say it all ended up at the poles. Some would certainly diffuse downwards and precipiate in the cooler zones only a few cm down.
So some transport certainly, bot not all of it. Given that the Moon is strongly depleted overal in Hg, there isn't that much (1/100th of the solar system average) to start with. This is part of the overal lunar depletion in volatile metals, used by some to argue the giant impact origin for the Moon.
You'd expect mercury to be scarce in the lunar crust, for the same reason you'd expect scarcity of other volatiles.
And those volatile vapors that don't escape to outer space move about the moon's surface. If their travels take them to a cold trap, there they will stay.
There are volatiles and volatiles. Gases are a very different issue to the volatile heavier elements. The Moon is depeleted in the whole range of heavier volatile elements, virtually the whole right hand side of the periodic table. These are crustal averages, not the result of some local process. There is no way that these these volatiles could re resupplied in any meaningful way.
Gases can be trapped at the poles from interplanetary space (both comet tails and the solar wind), as well as from tenporary unar atmospheres from impacts. This has been postulated for deaces, so recent discoveries are confirmation of theory, not some radical discover. The amounts are much smaller and the processes is different.
As far as we know Hg is not enriched in comets (I am not sure it has even been detected), so you would not expect any Hg accumulations to occur.
Your assertion that there's no mechanism to concentrate mercury in the cold traps is wrong.
I could have enunciated it better, but the basic asertion remains valid. There is no plausible mechanism to concentrate such large quantities of Hg at the lunar poles. The source amounts are extremely small, the most likely cold trap for the small amount that would be mobilised is only a few cm away from the mobilisation site, and there is no alternative Hg source (e.g. comets).
Is the same true of gold? I don't know. Off hand, I can't imagine a mechanism that would concentrate gold at the lunar poles. But just because I can't think of one, doesn't mean such a mechanism can't exist. We don't know the history of the minerals in the cold traps. While I'd agree the gold finding isn't conclusive, I reject the notion that it should be disregarded just because it doesn't meet our expectations.
The basic fact remains we have aboslutely no good reason at this stage to believe there is percent level gold at the lunar poles. It is just wishful thinking without further data.
We have further data. I would expect percent level Au, Zn, Hg and the rest to show up in the other remote sensing techniques - Gamma Ray and X-Ray spectrometry for example. As far as I know they don't.
The onus is really on people who say these elements are present at percent level to come up with good evidence. So far there isn't any. One measurement by an unreliable (for these elements) instrument, wih negative confirmation by other instruments means that we have no reason to think that there are Hg and Au deposits at the lunar poles.
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duplicate
Last edited by JonClarke (2012-01-05 02:19:01)
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Jon I would like to thank you for providing a strong critical viewpoint. If someone where to say 'we should do this' and everyone just said 'yup, tha'd be cool' we would quickly go back to scratching our rears stop thinking about it.
Secondly, as I said before, UV spectoscopy is not a reliable tool for measuring heavy elements. To draw far reaching conclusions, as is happening here, based on one quite possibly spurious reading from an unreliable instrument, completely unwarranted.
There are only a few things that could cause bad results from an experiment like LCROSS. There could have been interment malfunction in which case the data from those interments should be discarded. It could be noise in the instrumentation and a margin of error should be determined and hopefully published. Or the analysis of the data was flawed, in which case the error should be found and corrected. You assert that Ultraviolet Spectroscopy cant accurately classify heavy elements that there was only one set of data collected and the interment itself is unreliable; I have a hard time beliving all of your assertions. You may have forgotten that LCROSS took spectra data from infrared trough ultraviolet and spectra data at various wavelengths including infrared was collected from many different observatories around the world and good corroborating results where collected. I think we can at least rule out interment failure and I believe the LCROSS team is as competent as anyone to analyse and interpret the data.
Sorry I was unable to locate my source on the static gold concentration. Its something I read a few months back probably on nasaspaceflight.com It was just something I was throwing out as a possible explanation for the concentration.
As for the mercury the rate of decomposition and sublimation from compounds can be extremely slow and still have a profound effect simply due to the time scale we are dealing with.
I completely agree with you about governance, the best thing we could do for the commercial development of space would be to create strong property laws. Businesses need to be assured there investments in an area will be protected and should be granted exclusive access to areas they are actively developing and mining.
...For the cost of a single large lunar orbiter like LRO you can find, prove up and bring to production a world class orebody in just about any commodity you like. It does not matter if Musk is a miracle worker and can reduce costs to a 10th of what they are at present, it will take a lot more than an orbiter to prove up an orebody. Hundreds of drill holes, ground geophysics, thousands of assays, months of test work, getechnical surveys. It will always be easier to do this on Earth.
The cost of space hardware will decrease like everything. They build this stuff extremely inefficiently, each spacecraft is designed from the ground up and manufactured one at a time. Imagine how many hundreds of millions of dollars there is in designing your cell phone and necessary components, how much would it cost if they just built one. I hope access to LEO get down to $100/kg and have reusable solar powered ion tugs pull you to lunar orbit for $15/kg
so the transportation cost of freight on the lunar surface might be around $300/kg. It wont take too many billions to start a mine.
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JonClarke wrote:Hop wrote:Cite?
Lunar meteorite impacts can be as slow as 2.4 km/s.
Some perhaps, but very few.
This paper http://arxiv.org/abs/0907.3010 calls imapctors below 11 km/s "slow", Figure 3a shows that there are effectively none below 10 km/s,
No, figure 3a on page 7 does not show there are effectively no lunar impacts below 10 km/s. A significant portion of the the lunar bell curve lies to the left of 10 km/s. What you say is true of the dotted line (earth's impactors).
Furthermore, on page 12 the authors note their models don't match the lunar impact record. "One possible explanation is related to the impact velocity distributions. The leading/trailing asymmetry becomes more prominent when the average relative velocity between the Moon and the projectiles is low. The NEA-like particles are, by their dynamical definition, the “slowest” (relative to Earth) among all the known small body populations in the solar system. That even these slow particles may not fully account for the observed asymmetric distribution in the lunar crater record suggests that there may exist a presently-unobserved population of small objects near the Earth’s orbit that have even lower average relative velocity than the currently known near-Earth asteroids do."
There are a indeed a few below 10/s, but bulk of the are all above that km/s, only the tail of the histogram is below it. Page 7:
Overall, the average impact velocities of the clones on the lunar surface, ( 22.4 km/s) is almost the same as the average encounter velocity of the original particles at the Earth’s activity sphere. This means that lunar gravity plays only a minor role in accelerating particles to the lunar surface in our numerical model. Not only lunar gravity but the Earth’s gravity also plays only a small role: average impact velocity of the clones at the Earth’s surface is 23.1 km/s, not being very different from the average impact velocity with the lunar surface, in spite of the large difference of the escape velocities from the two bodies ( 11.2 km/s on the Earth and 2.4 km/s on the Moon)
JonClarke wrote:The text of this paper has slightly different numbers - average of 17 km/s and a lower limit of 12 km/s www.sciencemag.org/content/309/5742/1847.full.pdf .
Behind a pay wall. I'll note a 17 km/s average doesn't mean there aren't slower impacts. I am skeptical of the 12 km/s lower limit. I suspect you're misinterpreting this paper as you did the paper by Ito and Malhotra.
Go to a library. Not all knowledge is on the internet. It's a basic part of research. Misinterpreted the paper, no, I have not.
JonClarke wrote:Yet another paper http://128.97.36.172/Warren%20et%20al-s … aradox.pdf suggests 16 km/s as the average and suggests that this number has not changed much throughout the history of the Moon.
Again, an 16 km/s average doesn't demonstrate the nonexistence of slower impacts.
You can draw all the cartoons you like but it won't alter the fact that while they do exist (I have never denied this) but are extremely rare (which all the evidence points to).
Are you saying that low veolcity impacts are the norm? If so, what's your evidence?
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Likewise, the global composition of the moon is irrelevant to this discussion. By that logic I have news for you: the Earth's crust has a poor abundance of precious and heavy metals! Too bad we can't extract the resources we need from it.
Quite the opposite. Go to this web site http://www.chemicool.com/ and check the solar system vs terrestrial crustal abundances for elements of economic interest. Almost all are strongly enriched in the Earth's crusts. PGEs are among the few that are depleted. Which is why there are very rare. Other previous metals like Au and Au are enriched.
From this we can conclude, even without knowing about deposits, that the Earth's crust is well endowed. Comparing the crustal values with those of the Moon (or Mars for that matter) we see that these bodies are much less endowed.
We're talking about locally concentrated ores and volatile deposits, and the mechanisms which might create and/or protect them on or near the lunar surface. Due to vast differences in geology, impactor speed, and weathering, those mechanisms will be different than on Earth.
Unless less you talk about specific processes the above is too general to be useful. Magmatism and impact processes are very similar on the Earth and the Moon. Impact velocities on the Moon are not that different to those on Earth. Weathering is different for the earth and Moon, agreed, but what is the relevance of the difference to ore genesis?
Volatiles are a different story, they are there is large amounts, although the quantities are still rubbery by any ore reserve standard.
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Jon I would like to thank you for providing a strong critical viewpoint. If someone where to say 'we should do this' and everyone just said 'yup, tha'd be cool' we would quickly go back to scratching our rears stop thinking about it.
Glad you like it! :-)
JonClarke wrote:Secondly, as I said before, UV spectoscopy is not a reliable tool for measuring heavy elements. To draw far reaching conclusions, as is happening here, based on one quite possibly spurious reading from an unreliable instrument, completely unwarranted.
There are only a few things that could cause bad results from an experiment like LCROSS. There could have been interment malfunction in which case the data from those interments should be discarded. It could be noise in the instrumentation and a margin of error should be determined and hopefully published. Or the analysis of the data was flawed, in which case the error should be found and corrected. You assert that Ultraviolet Spectroscopy cant accurately classify heavy elements that there was only one set of data collected and the interment itself is unreliable; I have a hard time beliving all of your assertions. You may have forgotten that LCROSS took spectra data from infrared trough ultraviolet and spectra data at various wavelengths including infrared was collected from many different observatories around the world and good corroborating results where collected. I think we can at least rule out interment failure and I believe the LCROSS team is as competent as anyone to analyse and interpret the data.
Obviously I did not make myself clear - my fault. LCROSS was a great mission and the UV spectrometer a great instrument that delivered what it was design for - the composition of the gas plume. The team were doubtless very good people.
However it was not designed for heavy elements. I have never even heard of people using UV spectroscopy to detect heavy elements, and I am familar with most geological and spectral analytical techniques. If I am wrong, then somebody should to link to a site that shows this. UV spectroscopy is used to determine compositions of gases in space. It can't be trusted to give heavy elements. The UV spectometer paper on the LCROSS missions did not discuss the percent values of heavy elements - if the authors had thought they were significant, I would thought they would have discussed them. Percent Au in that quantity is unprecedented. But they didn't, until I have evidence to the contray I must assume that the instrument team did not believe them.
Sorry I was unable to locate my source on the static gold concentration. Its something I read a few months back probably on nasaspaceflight.com It was just something I was throwing out as a possible explanation for the concentration.
I saw that there too. I only lurk so did not object.....
As for the mercury the rate of decomposition and sublimation from compounds can be extremely slow and still have a profound effect simply due to the time scale we are dealing with.
Agreed. But first we need to establish that it is there.
I completely agree with you about governance, the best thing we could do for the commercial development of space would be to create strong property laws. Businesses need to be assured there investments in an area will be protected and should be granted exclusive access to areas they are actively developing and mining.
I have seen what lawless places are like. Not nice.
JonClarke wrote:...For the cost of a single large lunar orbiter like LRO you can find, prove up and bring to production a world class orebody in just about any commodity you like. It does not matter if Musk is a miracle worker and can reduce costs to a 10th of what they are at present, it will take a lot more than an orbiter to prove up an orebody. Hundreds of drill holes, ground geophysics, thousands of assays, months of test work, getechnical surveys. It will always be easier to do this on Earth.
The cost of space hardware will decrease like everything. They build this stuff extremely inefficiently, each spacecraft is designed from the ground up and manufactured one at a time. Imagine how many hundreds of millions of dollars there is in designing your cell phone and necessary components, how much would it cost if they just built one. I hope access to LEO get down to $100/kg and have reusable solar powered ion tugs pull you to lunar orbit for $15/kg so the transportation cost of freight on the lunar surface might be around $300/kg. It wont take too many billions to start a mine.
One would hope so. But a two orders of mgntitude decrease isn't going to happen soon. Even when it does to prove up a large lunar ore body would be a bigger effort than all missions to the Moon combined. It won't be cheap, and still more costly than finding such a deposit on Earth. Even if you increase the cost of the commoidty by ten that just makes lower grade terrestrial deposits economic. Remember that terrestrial mining costs are decreasing all the too.
Space mining makes sense in two areas - a commodity that is essentially nonexistent on Earth (He3 would be an example) - or for local use where it is cheaper than bringing it from Earth.
Other than volatiles, the most obvious lunar raw materials are Ti and Al, which exist at high grades (even my terrestrial standards), and are useful even for basic manufacturing. And some Fe of course. Forget about Au and PGEs.
Anyway I am off on by 30th wedding anniversary for the next four days, so this is my last post here.
Last edited by JonClarke (2012-01-05 03:28:01)
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It is a pity Jon Clarke is away as I was hoping he could answer this question of mine. The question is with the Moons history not that we have not found evidence of PGMs and Iron but why we cannot.
We know that the Moon is constantly being hit by meteorites etc we see the transient light and we estimate that meteorites of a mass of 1kg+ impacts the Moon at least 260 times a year. The nature of asteroids is that the majority are C class chondrites but a good minority are structurally stronger M class asteroids.
With all these impacts why is that we cannot find more evidence of the M class asteroidal impacts.
From Apollo we have the idea that the Moons regolith is a very impacted surface, loose regolith is on top of compacted regolith but that a real layer of solid rock may well be very deep under the surface.
The strong structure of M class asteroids may well be strong enough that without atmospheric heating that they will survive relatively intact hitting the Moon. Could this be why we are not seeing them. If they are such concentrated and buried then our sensors would struggle to see them. What would it take to actually test this idea.
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Hop wrote:JonClarke wrote:Some perhaps, but very few.
This paper http://arxiv.org/abs/0907.3010 calls imapctors below 11 km/s "slow", Figure 3a shows that there are effectively none below 10 km/s,
No, figure 3a on page 7 does not show there are effectively no lunar impacts below 10 km/s. A significant portion of the the lunar bell curve lies to the left of 10 km/s. What you say is true of the dotted line (earth's impactors).
There are a indeed a few below 10/s, but bulk of the are all above that km/s,
Using Photoshop to count pixels...
9%. 9% of impacts is effectively no impacts?
Hop wrote:JonClarke wrote:The text of this paper has slightly different numbers - average of 17 km/s and a lower limit of 12 km/s www.sciencemag.org/content/309/5742/1847.full.pdf .
Behind a pay wall. I'll note a 17 km/s average doesn't mean there aren't slower impacts. I am skeptical of the 12 km/s lower limit. I suspect you're misinterpreting this paper as you did the paper by Ito and Malhotra.
Go to a library. Not all knowledge is on the internet. It's a basic part of research. Misinterpreted the paper, no, I have not.
From a histogram showing 9% of impacts are below 10 km/s you conclude there are effectively no such impacts. I would call that a misinterpretation.
Furthermore, the Ito and Malhotra said that the evidence may indicate they're under estimating the slow impacts.
You can draw all the cartoons you like but it won't alter the fact that while they do exist (I have never denied this)
If you're saying 12 km/s is a lower limit, you are denying they do exist.
Are you saying that low veolcity impacts are the norm?
Absolutely not.
Velocity of a hyperbola is sqrt(Vesc^2 + Vinf^2). For most asteroids, Vinf is quite high and this is the quantity that dominates. But there are are number of asteroids with low Vinf, some have a Vinf of nearly zero. Hence I said lunar impacts can be as slow as 2.4 km/s. Which is entirely correct.
Somehow you have morphed this into slow impacts are the norm, a position I've never taken.
Hop's [url=http://www.amazon.com/Conic-Sections-Celestial-Mechanics-Coloring/dp/1936037106]Orbital Mechanics Coloring Book[/url] - For kids from kindergarten to college.
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It is a pity Jon Clarke is away as I was hoping he could answer this question of mine. The question is with the Moons history not that we have not found evidence of PGMs and Iron but why we cannot.
We know that the Moon is constantly being hit by meteorites etc we see the transient light and we estimate that meteorites of a mass of 1kg+ impacts the Moon at least 260 times a year. The nature of asteroids is that the majority are C class chondrites but a good minority are structurally stronger M class asteroids.
With all these impacts why is that we cannot find more evidence of the M class asteroidal impacts.
From Apollo we have the idea that the Moons regolith is a very impacted surface, loose regolith is on top of compacted regolith but that a real layer of solid rock may well be very deep under the surface.
The strong structure of M class asteroids may well be strong enough that without atmospheric heating that they will survive relatively intact hitting the Moon. Could this be why we are not seeing them. If they are such concentrated and buried then our sensors would struggle to see them. What would it take to actually test this idea.
I am back, it is a good question. There is certainly dispersed meteoritic iron globules throughout the lunar regolith (about 1.5%, I think). Iron metorites are be strong, but they are not strong enough to survive hypervelocity impacts.
I can't find an overall PGE content of the regolith offhand, but Ir appears to be at the ppb level.
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The abundance of Pt groups in normal regolith means little. What interests me are foreign objects like chunks of asteroid. Even if only one in a million large impacts leave big enough chunks behind to mine there is still that one in a million.
Before you could mine you'd have to locate your resources. Knowing the 3d structure of craters should help you determine the size speed and angle of the impactor. Ground penetrating radar may be able to identify the location depth and size of any remnants as well as its dielectric constant which will give clues to its composition. When a promising site is located you send a small lander (perhaps a dragon) to preform a test drill and more accurately analyse its composition.
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The abundance of Pt groups in normal regolith means little. What interests me are foreign objects like chunks of asteroid. Even if only one in a million large impacts leave big enough chunks behind to mine there is still that one in a million.
Before you could mine you'd have to locate your resources. Knowing the 3d structure of craters should help you determine the size speed and angle of the impactor. Ground penetrating radar may be able to identify the location depth and size of any remnants as well as its dielectric constant which will give clues to its composition. When a promising site is located you send a small lander (perhaps a dragon) to preform a test drill and more accurately analyse its composition.
What sort of goodies might be available? Carbon? Iron? Anything else?
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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Nope I'm looking for platinum and the like.
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Velocity of a hyperbola is sqrt(Vesc^2 + Vinf^2). For most asteroids, Vinf is quite high and this is the quantity that dominates. But there are are number of asteroids with low Vinf, some have a Vinf of nearly zero. Hence I said lunar impacts can be as slow as 2.4 km/s. Which is entirely correct.
Somehow you have morphed this into slow impacts are the norm, a position I've never taken.
In that case we agree.
However the majority are much faster than this, with most about 17 km/s.
Even 2.4 km/s is still substantial, meteorites with masses of less than a few hundred tonnes hit the Earth at less than 100 m/s.
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The abundance of Pt groups in normal regolith means little. What interests me are foreign objects like chunks of asteroid. Even if only one in a million large impacts leave big enough chunks behind to mine there is still that one in a million.
It means a great deal. The bulk of the impactor even in the base of small bodies is melted and dispersed. We know this from theoretical studies of impact processes, from observations from terrestrial impacts, and direct observations on the Moon. We have data from more than 130 km of lunar traverses on foot, by robot, and in vehicles. Not one meteorite was found. Compare with the number found on Mars over much shorter distances. That is the difference an atmosphere makes to meteorite preservation.
The regolith PGE concentration is of the order of 10 ppb, this is consistent with about 1% meteroitic iron at about 1 ppm.
I am not saying there are no larger meteoric fragments, but they are going to be extrenely rare. Why bother?
Before you could mine you'd have to locate your resources. Knowing the 3d structure of craters should help you determine the size speed and angle of the impactor. Ground penetrating radar may be able to identify the location depth and size of any remnants as well as its dielectric constant which will give clues to its composition. When a promising site is located you send a small lander (perhaps a dragon) to preform a test drill and more accurately analyse its composition.
What makes you think there will be enough fragments to be worth collecting?
What makes you think that fragments will be located inside craters when we know from Earth that they don't occur there?
What's the point of large fragments anyway?
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Nope I'm looking for platinum and the like.
Why PGEs?
What price would PGEs have to be to make mining the Moon feasible?
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Hop wrote:Velocity of a hyperbola is sqrt(Vesc^2 + Vinf^2). For most asteroids, Vinf is quite high and this is the quantity that dominates. But there are are number of asteroids with low Vinf, some have a Vinf of nearly zero. Hence I said lunar impacts can be as slow as 2.4 km/s. Which is entirely correct.
Somehow you have morphed this into slow impacts are the norm, a position I've never taken.
In that case we agree.
No, we don't.
I don't agree 9% = virtually no impacts.
Hop's [url=http://www.amazon.com/Conic-Sections-Celestial-Mechanics-Coloring/dp/1936037106]Orbital Mechanics Coloring Book[/url] - For kids from kindergarten to college.
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We have data from more than 130 km of lunar traverses on foot, by robot, and in vehicles. Not one meteorite was found. Compare with the number found on Mars over much shorter distances. That is the difference an atmosphere makes to meteorite preservation.
Given a small meteorite with a big ballistic coefficient, terminal velocity can be quite low. A very slow impact can leave an intact meteorite sitting on the surface.
I believe any intact meteorites on the moon would be buried beneath a crater basin.
That we haven't found any intact meteorites sitting on the ground certainly does not demonstrate there aren't any intact meteorites.
Hop's [url=http://www.amazon.com/Conic-Sections-Celestial-Mechanics-Coloring/dp/1936037106]Orbital Mechanics Coloring Book[/url] - For kids from kindergarten to college.
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Okay, so we need to add in communications satellites to the list of needed infrastructure - unless we can use pre-existing networks?
Could you keep discussions of economic viability to the appropriate thread, or perhaps even create a new thread, please? I intended this one to be for hashing out the basics of what we need, both mass and development wise, to make a sustainable Lunar architecture - once we've got a price tage we can figure out how to pay for it.
Use what is abundant and build to last
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I'm replying here to try to get both threads back on track.
http://www.newmars.com/forums/viewtopic … 89#p111189
I thought a single pole could be covered continously with just 2 satellites? Mind, we'll need to have a continuous link to EML1... could we get away with a direct link from the Lunar surface, and do away with satellites?
Say we need 3 Lunar sats... how many are we looking at for the Terran side of the operations? A dedicated GEO satellite, or more (we ought to be able to cope with the slight downtime from the eclipse...)? From what I've gathered so far, we're looking at maybe 1 to 6 satellites being required. We're looking at perhaps a billion dollars being required for this, yes, with a lifetime of 10 years?
Use what is abundant and build to last
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For near-side operations very early on, direct Moon-to-ground communication is very easy to do. Comm sats can be phased in as needed.
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I'm replying here to try to get both threads back on track.
http://www.newmars.com/forums/viewtopic … 89#p111189
I thought a single pole could be covered continuously with just 2 satellites? Mind, we'll need to have a continuous link to EML1... could we get away with a direct link from the Lunar surface, and do away with satellites?
Say we need 3 Lunar sats... how many are we looking at for the Terran side of the operations? A dedicated GEO satellite, or more (we ought to be able to cope with the slight downtime from the eclipse...)? From what I've gathered so far, we're looking at maybe 1 to 6 satellites being required. We're looking at perhaps a billion dollars being required for this, yes, with a lifetime of 10 years?
But surely NASA has Earth covered from all directions with satellite coms, and do we need constant communication with the lunar base? We didn't have that with Apollo did we? There are already satellites in lunar orbit aren't there? eg. the Indian satellite. I am sure the space agencies involved would be pleased to receive retainers amounting to tens of millions per annum?
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For near-side operations very early on, direct Moon-to-ground communication is very easy to do. Comm sats can be phased in as needed.
Only if you plan to use solar power half the time, or have a longest stay of under 14 days, all at a moderate latitude. I though we were talking constant, teleoperated robotic mining work at the poles here. Same to louis, BTW.
I thought a single pole could be covered continously with just 2 satellites? Mind, we'll need to have a continuous link to EML1... could we get away with a direct link from the Lunar surface, and do away with satellites?
Say we need 3 Lunar sats... how many are we looking at for the Terran side of the operations? A dedicated GEO satellite, or more (we ought to be able to cope with the slight downtime from the eclipse...)? From what I've gathered so far, we're looking at maybe 1 to 6 satellites being required. We're looking at perhaps a billion dollars being required for this, yes, with a lifetime of 10 years?
Pretty much like you said. Repeaters may be fine to control robots locally (they are indeed preferable, so robots don't have to carry long-range radios), but the base must have a satellite overhead all the time to pipe all those feeds to earth and vice-versa, unless it is at the near-side. And it has to be cheaper to put a telecommunications package in orbit than landing and installing it on a very long stick over the pole, so Molniya constellations it is (minimum 3 birds, at least one to have spares?). A single GEO bird would allow you to route all this to any given third of the earth 99% of the time (a bit less than a third, but you ain't putting your control station in Antartica), two would bridge that gap and provide redundancy. You might be able to buy bandwidth on existing satellites, but the largest user, the US military, is having big problems with that right now (too many drones out there), so much so we could see a resurgence of airships to cover the gap. The lunar comsats need a hefty launcher or a lot of internal fuel, or both, but that can be done with large GEO launchers. Note this only opens a single pole to communications, but the rest is adding more lunar satellites to the network covering more and more ground with each one, and you can make do with either periodic communication or two-week stays for exploration and prospecting. Global lunar telecommunications don't fit with the "developing" theme, right? This is how I would start.
Rune. You could probably push the birds to 15 years of operation, too, it is becoming common to do so.
Last edited by Rune (2012-01-12 23:03:51)
In the beginning the universe was created. This has made a lot of people very angry and been widely regarded as a "bad move"
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I wonder how hard it would be to drape a light fiber optic cable across the surface of the moon as your land or take off. The from the deepest dark side base it would still take less than 2000 miles of fiber to reach the near side and setup a direct surface station.
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Probably easier to put repeating communications satellite at Earth-Moon L2, which would be a stable point in the sky on the far side fo the moon.
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