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I see a lot of enthusiasm about the possibility of mining the Moon. But worryingly, I don't see much said about the potential horrific effects of this.

I mean, guys: the Moon is actually pretty damn small, as you know. Removing its mass could slightly alter its wobble and, eventually, orbit.

We could end up with a situation as shown in the film Time Machine, where the moon was destroyed by lunar colonists, making the Earth uninhabitable. I have to say; I have a vaguely ominous feeling about this idea.

I suppose my question is: are they genuinely serious about mining the Moon heavily?

Thank you.

Uhoh asked who I mean by 'they'. I'm referring to prospector organisations and various nations.

Others have pointed out that the Moon is far from, as I put it, 'pretty damn small'. And that it can easily handle decades - even centuries - of mining with no adverse effects. Well, firstly, I meant the Moon is relatively small. Secondly, I just cannot shake the feeling that it's a bad idea to physically undermine (no pun intended) a celestial body that's so close to us.

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    $\begingroup$ In the solar system, only a handful of gas giant moons are of comparable size to Luna. Earth and the moon are very nearly a binary planet rather than a planet and moon. The moon is not "pretty damn small": upload.wikimedia.org/wikipedia/commons/4/4f/… $\endgroup$ Jul 30 at 22:43
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    $\begingroup$ Some numbers: TOTAL mining of EVERYTHING on Earth is less than 14 billion tons pr year. The sum total of everything that has been mined throughout all of history, PLUS every mineral reserve for future mining of any kind, is on order of 2 trillion tons. The moon weights 37 billion times as much as all past and future mining on Earth summed together $\endgroup$
    – PcMan
    Jul 31 at 3:14
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    $\begingroup$ Orbits aren't knife-edge balances of distance and velocity, where a tiny nudge results in disaster. If an ultra-tech sci-fi civilization decided to take 99.999% of the Moon using whatever Viking space magic they have at their disposal, the remaining 0.001% of the Moon remains pretty much in the same orbit it is now, as does the Earth. $\endgroup$
    – notovny
    Jul 31 at 12:23
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    $\begingroup$ Not the moon, but space mining: Sabine Hossenfelder talks about it on YouTube. She observed that a number of companies were formed about a decade ago, but they've had trouble sustaining investor interest and have been bought by other companies who are more interested in their assets than in their mining missions. So there's that. I think some people have gotten way ahead of the curve when they predicted a space revolution. youtube.com/watch?v=SYheVZQQHXk $\endgroup$
    – Greg
    Jul 31 at 17:44
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    $\begingroup$ "the Moon is relatively small": you keep saying this, but the moon is the 9th most massive solid object in the solar system and the 14th most massive object overall. We're not going to disturb it or its orbit or do anything else to cause problems on Earth by mining it. $\endgroup$ Aug 1 at 21:38
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the Moon is actually pretty damn small

The Moon is actually pretty damn enormous.

The mass of the Moon is about $7.34 \times 10^{22}$ kilograms.

As a point of comparison, all the copper ever mined on Earth comes to 700 million tons - that is, $7 \times 10^{11}$ kilograms, or $\frac 1 {100000000000}$ of the total mass of the moon.

Removing that much mass won't change the Moon's rotation or orbit detectably.

Even a small moon such as Uranus' Miranda, which at 470km diameter is just large enough to be pulled into a spherical shape by its own gravity, has a mass of $6.4 \times 10^{19}$ kg, or ~90000000 times as much mass as all the copper ever mined on Earth.

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    $\begingroup$ While the OP is concerned about the effects of mass removal, they are really asking for an answer to "are they genuinely serious about mining the Moon heavily?" That part may be difficult to answer if we can't nail down who "they" are. $\endgroup$
    – uhoh
    Jul 30 at 22:39
  • $\begingroup$ @uhoh By 'they', I suppose I mean prospector organisations, various nations and the like. $\endgroup$ Jul 31 at 9:55
  • $\begingroup$ @WhitePrime I'd left a comment under your question asking for clarification. If that's what you mean, it would be great if you edited your question and added that in. Thanks! $\endgroup$
    – uhoh
    Jul 31 at 14:21
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    $\begingroup$ Other answers do better than I could with the math and physical consequences here, so I'll just address the "are 'they' really interested in mining the Moon" portion of the question. The answer is yes. National space agencies (plus ESA) are pretty heavily engaged in this work to support in-situ activities. At the very least, that part is going to happen on some scale this decade. Whether it becomes commercially viable (likely volatiles at first) is an economics question. But there are money, intent, and policy all behind this. $\endgroup$ Aug 2 at 18:37
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Yes, people are serious about mining the moon. Here's a US government contract. (Currently inactive as it was issued and due in 2020.) But it constitutes a serious solicitation, and request for quotation.

An excerpt from the summary:

NASA/NSSC has a requirement for Purchase of Lunar Regolith and/or Rock Materials from Contractor.

It has fun things in it like this: (which I have excerpted and reformatted to be brief)

The Contractor shall:

  • Collect from 50g up to 500g of Lunar regolith and/or rock materials (“Collected Material”) from the surface of the Moon (Luna).

  • Be responsible for performing all activities necessary, including:

    • Determining method(s), providing and or developing equipment, deployment/launch/landing, and operation of all systems the Contractor’s method(s) requires. (this purchase does not include development, production, or launch of space vehicles)
    • ...

Note that 500g is not a moon-wobble-worthy amount of mass.

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    $\begingroup$ Love the last paragraph! $\endgroup$ Aug 2 at 8:05
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Motivation

The moon is rich in a few important natural resources, namely:1 2

Stuff Context Amount Utility Challenges
water data from orbiters indicate that the poles – particularly the South Pole – are rich in ice water. the water may have evolved on the moon naturally or deposited through bombardment by water-rich meteor strikes. 31,059 km2 of permanently shaded areas may be covered by thin ice coatings can be used for rocket bi-propellant fuel 1. thick ice sheets might not exist, 2. it's an exhaustible resource.
sunlight certain areas of the polar South Pole receive nearly constant light, while still being close to water ice sources. virtually unlimited supply solar cell arrays can capture the sunlight, establishing permanent crewed bases on the surface
3He isotope solar winds have implanted this isotope onto the regolith 1m tonnes, but that's still 10-20 ppb can be used for nuclear fusion 1. extraction might not be feasible, 2. extraction, if feasible, requires tonnes of processed regolith in order to acquire 1 g of 3He, 3. current fusion reactor prototypes use more energy than produced, 4. it's an exhaustible resource
N - 5 ppm in the regolith nutrient required for farming in a biosphere 1. very limited quantities, 2. it's an exhaustible resource
C originates from solar winds and micrometeorite impacts 82 ppm in the regolith required for farming; production of lunar steel 1. very limited quantities, 2. it's an exhaustible resource
Si the three most common minerals on the moon – plagioclase feldspar (usually anorthite), pyroxene, and olivine – all have Si in them. 21% of lunar surface materials by mass glass, fiberglass, and ceramics; solar cells; perhaps as semiconductive material if it can be purified enough 1. achieving purity to be used in solar cells and electronic chips could be challenging, 2. would require breaking down the minerals listed.
Al it's in anorthite 13% of the highlands by mass / 5% of the masa it's a good electrical conductor; it can also be burned for propulsion fuel 1. would require breaking down plegioclase
Ca it's in anorthite 10% of the highlands / 8% in the masa ceramics; it's a good electrical conductor in some situations; can be used to help make solar cells 1. would require breaking down plegioclase
Fe the iron in pyroxene, olivine, and iron-titanium minerals like ilmenite is all in the ferrous (2+) oxidation state, compared to iron on Earth which is also sometime in (3+) state. some of the iron on the moon is metal, often Fe-Ni, deriving from meteorite impacts. 5% of the highlands / 15% of the masa; also, 0.5% of the regolith by mass steels and alloys; dust: parts made through powder metallurgy 1. would require breaking down the minerals listed.
Mg nearly all is in pyroxene and olivine. for (+2) Mg, the same is true about what was said of (+2) Fe. 5.5% applications as an alloy in aerospace, automotive, and electrical applications 1. would require breaking down the minerals listed.
Ti there are basalts that contain a massive quantity of Ti, in the form of ilmenite, which it is 5-8% by mass. this is 10x as much Ti as Earth rocks. < 1% in highlands and between 1-5% in the masa alloys for lightweight spacecraft 1. would require breaking down ilmenite; 2. it's an exhaustible resource
REM / lanthanides rare earth elements, though common, are often very dispersed on our planet, and mineral deposits are rare; as a result, China extracts the vast majority of REM. rare depends on the element, but various industrial uses, including optical and ferromagnetic ones; automotive industry; "green technologies". extraction on the moon could end pure dependence on China 1. identifying deposits; 2. extraction

Note that many of these are in very small supply by mass, and effectively acquiring them completely would not alter the moon's mass materially. Much of the ppm and percentages I provided are for the surface-level only; the deeper layers may never be touched at all.

Helium

The last person to walk the moon was a geologist named Jack Schmitt, who studied the composition on the moon. He's essentially the only natural or physical scientist who's stepped foot on the moon. He has since written a book, Back to the Moon (2007), which he proposes long-term renewed exploration and expedition to the moon, revolving around the nucleus of mining 3-He for energy production purposes as socioeconomic justification for such return. Demonstrating a political bias, he also delved into the goriness of a pro/con analysis of various private or public methods of achieving this, positing that some are better than others, and arriving at the dubious result that the private sector was the superior solution to this. In order for the detailed plans for lunar mining to be successful, it would need to attract significant private-sector investment, according to him,3 and the legality of who has claim over hypothetical mining operations remains unclear (theoretically nothing seems to prevent private ownership; the 1967 UN Outer Space Treaty only prevents political ownership).3 4

Either way, assuming that we could extract and find a way to use the Helium for fusion as a solution to the eventual decline of fossil fuel quantities available, and as a way to stem the effects of greenhouse gas emissions, the amount of Helium that would be extracted would only be a few hundred thousand tonnes at most, which is insignificant w.r.t. to the mass of the moon.

Extracting other elements

The moon is 73q tonnes, so assuming 1 metric ton removed each day, it would take 220 million years to deplete just 1% of the mass.4

enter image description here Source: 911 Metallurgist, as posted by JPL NASA4

Need to make a cost-benefit determination as to whether or not the risks involved in causing some level of altered orbit or affecting gravitational tides is worth the value produced from extracting the natural elements on the moon. It appears that the risk is very low, assuming the rate of removal is steady and slow. For some things, such as REM / lanthanides, the risk/reward ratio looks fairly attractive because they are valuable but only represent a trifling small proportion of the mass. But the same could be said about Titanium, Iron, and Silicon near the surface.

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  • $\begingroup$ I do not whatsoever wish to slight the writer of the answer I chose to accept. But, I would've chosen your brilliant one if it had come earlier. $\endgroup$ Aug 2 at 2:54
  • $\begingroup$ Contrarily to @White Prime, I do not find this answer very eye-opening. True, there is an inventory of "items of interest". But the answer avoids discussing whether the resources are for bringing back to Earth or to be used in-situ. I would wish to see comparisons such as abundance on E vs on M (A_E/A_M), cost of extraction (C_E/C_M), values for usage (V_E/V_M). That's the cost-benefit analysis I wish to see, to be convinced whether "they are genuinely serious". $\endgroup$
    – Ng Ph
    Aug 2 at 17:28
  • $\begingroup$ White Prime, thanks, I hope that it was helpful $\endgroup$ Aug 4 at 18:36
  • $\begingroup$ to be fair, I already addressed several of your concerns, even if hard ratios for all of the materials weren't given. many of the rocks on the moon have high iron, aluminum, and magnesium content, which would be used to make alloys. I said that titanium is 10x more in ilmenite than Earth rocks. I mentioned that the water, sunlight, C, and n would be used on the moon, whereas the metals and He would be brought back for industry and nuclear fusion. I also talked about how lanthanides are sparse on Earth. this all makes me think that you didn't fully read my answer, or you misinterpreted parts. $\endgroup$ Aug 4 at 18:43
  • $\begingroup$ as for asking the ratios related to costs incurred from extraction and transportation, those numbers might not even be known or estimates in the public purview. asking for such level of detail is, from my standpoint, unreasonable, considering how long it took for me to even make my answer as extensive as it is. it's not like I'm getting paid to write this content. $\endgroup$ Aug 4 at 18:43
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It might be more correct to say there are people who are serious about liking the idea of mining the moon. There are no serious space agency programs or commercial enterprises attempting to do so. It should be noted that NASA and other space programs do look at in-situ resource utilisation apart from promoting the idea of a future - eventually - where mining space based resources could be commercially viable.

In-situ resource utilisation is technically "mining" but at very small scales - either to reduce payloads/improve overall mission capabilities or as experiments intended to show that it is possible to improve overall mission capabilities by such means. This allows use of mineral resources that would not otherwise be economically viable - in effect competing against high launch and transport costs, not against Earth's mineral resource costs. Economically viable commercial mining that exploits lunar minerals for use by commercially viable space industry or export to Earth is far beyond current capabilities.

It should be noted that there are no exceptional mineral resources of high economic value found on the moon - and very little likelihood of high grade ore bodies such as mining on Earth exploits; the geological processes that formed them on Earth are mostly absent. The presence of valued minerals at low concentrations is not sufficient to make them exploitable. Concerns that so much mining could be done that it could change the moons orbit have no real basis - there is no mineral resource there of sufficient value or abundance, nor technological capability to do so.

It does seem likely that high concentrations of nickel-iron (which may contain Platinum Group Metals at tens of ppm) will be found in impact craters but that may be the best commercial ore there is to be found - and that can be found in much greater abundance in asteroids and the metals they contain can be found and exploited on Earth at much lower cost.

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It really comes down to the plans of future space explorers and what resources would be available on the Moon and how beneficial they could be.

Currently there are a lot of maybes. The Moon has water resources (as ice), it also has helium 3 and titanium. We don't know if any of them are present in economic quantities or how easy of difficult it would be to mine and process the resources. Ice and titanium would be useful now and in the future. Helium 3 however, is currently a bit of a dream for some. We first need to prove we can make the ever elusive sustainable nuclear fusion reactor.

Sourcing materials for space exploration on Earth and sending it into space is expensive, partly due to the strength of gravity on Earth. The Moon's gravity is $\frac{1}{6}$ that of Earth's which makes it easier to get things off the Moon and into the cosmos.

Stuff that is mined from the Moon and sent into space means the some stuff that could be mined on Earth is used on Earth. We may need that.

If we are to continue space exploration and expand our efforts, mining the Moon, Mars, asteroids, or whatever cosmic resources are out there are all potential options but we first need to quantify what resources are available and that will require further additional expensive exploration.

Flying a probe over the Moon can tell us what resources are present on the surface of the Moon as a thin veneer. It doesn't gives us the depth of such resources which is required to give quantities. Additionally we know nothing of the potential underground resources on the Moon or elsewhere. Is there copper, zinc or nickel 100 meters below the surface, or deeper? We need drilling rigs to give us that knowledge.

It's an recursive Catch 22 situation, we need funding and initiative to explore and discover potential. We then have to decide what that knowledge and discovered potential may be and whether it is worth repeating the cycle for more knowledge and potential. After a number of iterations someone will decide whether a mine will be established on the Moon, or elsewhere. Its performance will influence decisions about other potential mines on the Moon and elsewhere.

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    $\begingroup$ The common materials on the Moon can be quite useful, too: commons.wikimedia.org/wiki/File:Moon_vs_earth_composition.svg . Aluminium, magnesium, iron, silicon, oxygen, titanium. Even raw rocks can serve as radiation shield. To get them into space we could use a solar powered sling shot, mass driver or space elevator rather than flying through heavy Earth's atmosphere with rockets. $\endgroup$
    – darsie
    Jul 31 at 7:33
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The common materials on the Moon(as well as asteroids, but most of the good ones are much further away and not practical momentarily) are very useful to humans and are far more accessible on the Moon than on Earth(most of Earth's stuff is in its mantle or core). Mining these materials on Earth's crust causes huge pollution that WILL kill in a matter of decades, rather than the millenia(at our current rate of material consumption) it would take to alter the Moon's orbit with mining.

"I mean, guys: the Moon is actually pretty damn small"

The Moon is huge by our standards, more than huge enough to power humanity's material needs for centuries with almost no change of mass(of course, we will advance technologically, but that also means going out to the asteroid belt to get even more materials).

Conclusion:

Our current technological,"prowess" will barely make a scratch on the Moon should we go to mine materials there. The actual horrific aftermath is if we don't go back to the Moon to mine, and keep poisoning our planet. Don't worry about far-future humanity maybe altering the Moon's orbit. Worry about us, right now, poisoning our own planet in desperation for resources. The sooner we stop mining on earth and start mining on the Moon, the better.

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  • $\begingroup$ "causes huge pollution that WILL kill in a matter of decades", to quote Carl Sagan, extraordinary claims requires extraordinary evidence. What the evidence for such a claim? $\endgroup$
    – Fred
    Jul 31 at 9:23
  • $\begingroup$ I should've been clearer when I said 'the Moon is actually pretty damn small'. I meant it's relatively small. It's small enough to be affected by concentrated mass removal. $\endgroup$ Jul 31 at 10:04
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    $\begingroup$ @WhitePrime except as has been pointed out already, it's not. The notion that mining could affect the moons orbit to a measurable degree is nonsense, the suggestion that it would actually be hazardous simply has no basis in reality. $\endgroup$ Jul 31 at 13:43
  • $\begingroup$ @Christopher James Huff I made a small edit. $\endgroup$ Jul 31 at 15:36
  • $\begingroup$ @Fred let me rephrase. It has a strong probability of killing us. As for evidence, simply go to a mining facility, note that there are hundreds of thousands of those across the world and even more to refine the materials, there's your evidence right there. $\endgroup$
    – Gregory
    Aug 1 at 7:03

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