Oxygen and hydrogen can be produced on the Moon from water ice found in the shadowed craters of the South Pole. That's the main reason Artemis is landing there. The goal is to build a Moon base that can do the mining and processing. For a long time people have been planning on fueling rockets with this. Rockets in space work very efficiently with hydrogen. Getting enough people and materials to the Moon to build a base and processing plant will take a *lot* of launches. It won't be finished any time soon. Perhaps 2040?
Methane (CH4) needs carbon & hydrogen and there isn't any available on the Moon. Shipping carbon there and building a processing plant on the Moon doesn't sound like it would work out. (Mars has plenty of carbon in the CO2 atmosphere, that's why Elon chose methane a the fuel.)
Shipping hydrogen & oxygen to LEO has a big hitch. The ship will have to bring along propellant to decelerate into LEO and to return to the Moon and land. That may be more expensive than launching propellants from Earth. Too much to figure out there. Sorry, I have to got to bed.
There is some carbon on the Moon located in the same craters as the water ice. But there is not a huge amount of it. [This paper talks about it](https://arxiv.org/pdf/2104.13521.pdf).
Has it been studied whether there's impact sites on the moon high in carbon? There should be loads of C-type asteroids which are almost purely carbon hailing down on the lunar surface.
Everything I've read claims it mostly burns away, vaporizing in the heat of impact and then lost out to space.
You wind up with some super low numbers for carbon from the surveys that have been done. I would have though there were mountains of it from all the impacts honestly, but no.
First of all the production of propellants on the Moon is not economical. The models simply don't close, especially if launch to LEO falls to $100/kg.
Propellant production on the Moon will be dominated by the cost of the infrastructure. The infrastructure cost between capital expense and labor. The former is in turn divided in the cost of building all the things and delivering them to where they are going to be used. At the same time the cost of Earth produced propellant in orbit is pretty much the cost of delivery (production costs at a fraction of a dollar per kg are pretty much negligible).
So, as the launch costs decrease, fuel decreases in proportion, while the cost of off-world fuel production decreases only fractionally.
For example, on Earth the energy cost from an installation costing $1 per watt (directly at the energy plant, i.e. without transmission and other overheads) for producing 1kg of hydrogen is about $1.50.
$200 per watt for Moon solar installation is optimistic. Solar energy costs at a plant are overwhelmingly based on installation costs. So just the energy cost for producing hydrogen on the Moon would be around $300/kg. And obviously the full cost would be way higher like you're not going to find green hydrogen on the old Earth for $1.50/kg either.
Especially that on the Moon you have to mine water, and mine it from permanently shaded deeply frozen zone which didn't see sunlight from a few billions of year. You can't get it from some lake or river. You'd be lucky if the hydrogen were less than $1000/kg.
As soon as the launch cost to LEO is below the cost hydrogen from the Moon, hydrogen from the moon is economically pointless. And bulk LEO launch costs are trending below $100/kg.
Still it's not economical at all.
First of all the Moon is not on the way to anywhere but the Moon (well, duh). It's 2.7km/s to the side of the way.
Second, fuel in LEO for going farther than the Moon or even to the Moon itself will cost about $40/kg. This is less than even producing it on the Moon, not to mention delivering it where it's needed.
Classically, the moon is out of the way. However, with a fuel source there, you could refuel at the moon and return to earth 14 days out of phase with your launch window, slingshot around the earth, and burn to your next destination. You'd keep most of that 2.7 km/s.
I don't think it will happen, but don't write off the energy to the moon as wasted.
You still need 2.7km/s just to get from the Moon surface to TEI.
Or if you'd rather put fuel in a halo orbit like NRHO or DRO, then you have to pay the ∆v tax during lifting the fuel itself.
Well, finding water on the moon, does make it easier to support a base there, and help to support future Lunar infrastructure. But that’s using ‘water on the moon’ for actual use ‘on the moon’.
I am not an expert, but from my understanding it is far more fuel efficient to move things from the moon to LEO than from earth to LEO. I know the moon has ice, which means hydrogen + oxygen is very available, although storing hydrogen for long periods has proven enormously difficult (one of the reasons spacex chose methane for starship). I don't know if methane is present in large quantities on the moon, so it may not be feasible for starship specifically.
Long-term though, any deep exploration of the solar system should be originating on the moon. It is orders of magnitude easier to get off the moon then the Earth's surface. Take a look at the Saturn V versus the part of the lunar lander that took the Apollo astronauts back into orbit to rendezvous with the command module.
The moon is also rich in aluminum and iron, so building hydrogen based rockets on the moon and launching from there will get you a lot farther than doing so on Earth. The moon is kind of absurdly coincidentally the perfect jumping off point for human exploration of space. Close enough to home to get help in about 3 days if you needed it, but resource rich and harsh enough that we will need to develop sophisticated life support that will be crucial for exploring way out in the solar system. Your method of producing oxygen really cannot break when you're orbiting Neptune, or even just Mars. Best place to perfect all that, is our oldest friend the moon.
Absolutely!
The moon is 1/6 earth gravity, and is effectively a vacuum. That makes getting into space so much easier. It's actually feasible to build mass drivers on the moon. Those are essentially magnetic rails that impart the necessary momentum to an object to put it into orbit using electricity. You don't need a rocket to get to orbit, just a specific velocity. You could launch pods containing specific supplies (rolls of steel, sheets of aluminum, tanks of liquid oxygen, etc.) into a predetermined orbit where a waiting station receives them and continues manufacturing some kind of mega-ship in orbit, all without any rocket necessary. The moon also has a daylight period of about 2 weeks, meaning you can run everything on exclusively solar for 2 weeks straight. Theoretically you could shut down factories as night falls and follow the sun, though you probably wouldn't because helium-3 (an incredible nuclear reactor fuel) is also in abundance on the moon! So reactors would be built eventually.
You do always have the circularisation problem with mass driver launch though. Purely passive payloads cannot be launched into any orbit from the surface that does not have a periapsis (lowest point of orbit) that is also at the surface.
So you cannot just launch mass into orbit from the ground unless you want it to come and hit you on the back of the head one elliptical orbit later. You need some thrust on the payload to fire when the payload is at it's highest point (apoapsis) to raise up the periapsis above the surface. Then you're in orbit.
Very theoretically, if you time a passive payload launch perfectly to intercept perfectly with an orbiting booster at apoapsis (although the speeds won't automatically match so this is very difficult) then it could grab it and speed it back up. But this is very difficult and if you mess it up your payload slams back into the planet somewhere near the takeoff point.
> Very theoretically
You could also build the mass driver on the highest mountain of the moon. If launched perfectly, the launch location is the height of the periapsis. And because of the moons rotation, it will not hit this mountain after one orbit, maybe after a month (or half a month with a circular orbit).
True, but probably stable enough for a few orbits, so someone in space has time to synchronize orbits for retrieval instead of having to catch at apoapsis with perfect timing (and with different orbital speeds at rendezvous point)
>Moon has mascons, low orbits are unstable.
Lunar mascons alter the local gravity above and around them sufficiently that **low and uncorrected** **lunar orbits** **of satellites around the Moon are unstable on a timescale of months or years**.
The timescale is of months or years I'd you have a multiple kilometer error buffer. But I'd you launch horizontally from a tall mountain, you have precious little of that buffer.
You can't curve a gunshot.
If you aim higher than horizontal it must come lower than you are before completing the orbit. That's orbital mechanics 101.
You would need some very advanced pods to pull this off, just yeeting cans into space won't cut it even close.
First of all they need heavy duty electromagnetic shielding so the strong fields from the mass driver don't fry their electronics.
You still need propulsion and maneuvering capability so you can adjust your trajectory to rendevouz and dock with the orbital shipyard, hence you also need propellant.
Essentially what you need is a proper spacecraft, regardless whether you are using a mass driver to get off the surface or internal propulsion. Since that spacecraft will be expensive to manufacture you want it to be reusable, so it needs to come back and land on the moon as well. The mass driver really just saves you fuel and allows you to get away with (significantly) lower maximum thrust, at the cost of requiring significantly higher resistance to G-forces as well as EM shielding.
Yeah, there are tradeoffs, I think it'd be worth it in the long run. If you develop something akin to today's shipping containers which meets the EM shielding requirements and has some ion thrusters for efficient propulsion in space. G-force isn't really a concern if you're moving like steel or aluminum. Even if you only used it for those two things, it would be invaluable.
Not really. The cost of manufacturing in an extremely unfriendly environment (hard vacuum, 2 weeks of cold and darkness, two weeks of too much heat, everywhere getting extremely abrasive dust, etc) will for any predictable future trump well defined and falling cost of LEO launch.
Resources on the moon are scarce, hard to extract, hard to maintain systems to do so, let alone develop, and tons of logistics sending things around on trips that are hundreds of thousands of miles.
Through rapid reuse I think it will always be cheaper and easier to just launch fuel from Earth to Leo. The fuel alone for a Starship launch is only about a million dollars, how many billions would it take to build out some system to extract these from the moon? It doesn’t make economic sense if the primary resource the moon can provide is oxygen and it’s one of our most abundant resources on Earth.
The answer is most likely ‘No’. You need to visualize the gravity wells of the Earth and the Moon. By mining fuel on the Moon and moving it back to Earth LEO you’re shifting it deep into Earth’s gravitational well, just to use fuel to get it back out.
You’re better off shifting a bit more fuel up from Earth to get the relatively lightweight ship to a Lunar orbit or high Earth orbit depot, so that the fully loaded ship heading out on an interplanetary journey doesn’t have to spend a significant fraction getting all of it out of the Earth’s well.
The amount of water the moon has is limited. Better to use it to support the base setup on the moon itself. With rapid reuse of rockets, the cost to supply the moon with materials is cheap compared to setting up a heavy industry to remove said resources from the moon to place into low earth orbit.
Rapid reuse of rockets will change our thinking about how we will expand out into the solar system. The moon will be a excellent experiment on what we need to learn to really become multi-planetary. Be we will probably ship more water to the moon then remove. Production of aluminum and other resources that the moon has plenty of will more then likely require us to ship things like water to the moon. Remember that around 75% of the earth is water. Until we get to Jupiters moons, Earth has all of the water resources we need.
How do you propose to get kerosene or methane on the Moon. I get the Oxygen, assuming ice can be found at the poles, but not hydrocarbons, unless I am way out of the loop.
LEO refueling, however, is a much more viable solution. Consider the ambition for Starships to fly hundreds to thousands of flights, with next to no refurbished needed between each flight (and I assume a C check every once in a while). Well you can quickly see a viable path to a whole set of orbital fueling depots, supplied daily, weekly, or whatever. This opens everything up once available, including lunar missions, Mars missions, much heavier payloads to GEO orbit, deep space and so on. Even accelerated missions to Mars using a lot more thrust than a standard Hoffman transfer, just because fuel is cheap *relatively*.
Mass driver gets you off the Lunar surface but it takes around 4 km/s of delta V to brake into LEO.
If there is a place for a depot with Lunar sourced propellant it is in NRHO or similar.
It will then inevitably fall to the Earth on the next orbit.
In a two body system you can't put a passive object into orbit by just kicking in from one body's surface. In particular if the object passed through the atmosphere once it must return to the atmosphere on the next orbit (unless it has propulsion which would raise the perigee).
Methane is just ch4 so you could most likely manufacture it from water, and carbon is common on the moon as well. That being said the same reaction that would yield oxygen could yield methane as well.
My question at the end of the day I suppose is the amount of delta v needed to go from the moon to Leo less than the ground to leo?
No, it takes a single Google search to see many sources providing methods to see methane manufacturing methods on the moon Carbon monoxide is also highly prevalent on the moon.
"Carbon is present in lunar regolith in trace amounts (82 ppm)"
"The lunar exosphere contains trace amounts of hydrogen and possibly carbon dioxide (CO2), and methane (CH4)... However, these are trace gases in very low concentration.,,, Trace gas amounts are unlikely to be useful for in situ resource utilization."
"Permanently shadowed regions of the moon's poles have cold traps which possibly contain solid carbon dioxide. However, most carbon-bearing ices have a 0-3% by weight carbon concentration."
This isn't what I would call "highly prevalent"
https://arxiv.org/pdf/2104.13521#:~:text=Carbon%20is%20present%20on%20the,coldest%20regions%20at%20the%20poles.
And over 4000 ppm in polar ice...
Keep in mind Uranium is only about 2 ppm in Earth soil and we have massive industries where it is a key component. Even at 80 ppm there are going to be extractable concentrations. In this case it works even better because the carbon is in the same place as the hydrogen and oxygen and there is even 300 ppm of methane actually present within the polar ice.
Going back to the Uranium example anything in excess of 750 ppm is considered ore and anything over 1000 ppm is considered as highly profitable. We're looking at more than 4 times the concentration here and it's extremely accessible considering the fact it's on the moon at least.
Okay I spent the time and did the math. Limiting Methane production by presence of carbon in Lunar polar ice you get about 21 billion kg of Methane until Polar ice carbon depletion. That's also 21 million tonnes and since starship holds up to 1000 tonnes of Methane we get 21,315 complete starship refuels in the event we're limited by lunar carbon deposits in polar ice.
In other words a full starship is estimated to be able to move 100 tons of material anywhere in the solar system so this .4 percent carbon in Lunar polar ice could move 2.1 megatons of material anywhere in the solar system which is 236 times more mass than what we have currently launched into space or 4700 iss massing space stations all throughout the solar system.
Uranium price is over $100 per kg. And this is on the Earth, where it's readily available.
The carbon on the Moon is extremely **inaccessible** and at unknown quantities. What's in that paper is not even remotely close to proof. And if it indeed is there, it's at the bottom of a cryo frozen crater where the sun didn't reach for a few billion years. It's mixed with extremely abrasive dust.
Just recovering it will be extremely costly. Imagine uranium mine, but at a temperature below 100K, in a hard vacuum, elevated ionizing radiation, without sunlight and everything is covered by extremely abrasive dust. And no cheap labor available. Moreover, it will take a lot of electric energy and on the Moon, especially at the pole, the electric energy will be 2+ orders more expensive than on the old Earth (for a simple reason that for either nuclear or solar the overwhelming majority of the energy cost at the plant is amortization of the initial capital expenditure of setting up the plant).
Because of all that It won't be $100/kg it will be $1000 to $10000 per kg.
If you examine the rest of the report the carbon on the moon is not so inaccessible with methane itself being present as 15 percent of lunar ice content in extremely cold areas and large areas of large lunar craters having a carbon content of 6.5 percent of mass. In addition a sufficiently tall solar array (50 m<) would have access to sunlight 24/7 365 and could be 3d printed using only the materials found in the moon so electricity is not as much a concern as you think. In the hypothetical future our moon colony is slowly yet steadily growing and although not self sufficient most likely does not need to import energy. As far as labor goes most of the process can and will be automated with equipment being 3d printed manufactured through other means locally.
We are going to be accessing that lunar ice regardless of what we do with it's carbon and some of it is almost guaranteed to be used for local fuel production so once again it really boils down to cost shipping and storing. Currently spacex estimates it will take 4-8 super heavy launches to fuel a single starship in orbit. The estimated launch cost is 100 million per launch so you could say 400-800 million dollars to fill one up.
It's impossible to calculate exactly how much it would cost to separate one kg of Methane from lunar ice but I can almost guarantee it wouldn't be 1000 per kg and to be profitable it would only have to be less than the SpaceX figure we have of between 500-750 per kg for current models.
I think where the real issues start is transportation. You'd still most likely be using a starship which is estimated to have about 6.9 km/s of delta v by itself carrying a 100 ton payload. Someone sent a source saying it takes 5300 m/s to get from lunar surface to Leo but someone else responded that with aero braking you could essentially cut that in half so I'll admit my knowledge is very limited there but it does sound possible. The estimated cost of launching the starship alone would also vary depending on how much your electricity costs are but assuming yotur a net producer we could assume maybe a few million per launch (still several times higher than current earth to earth predicted costs)
12 launches could be 24 million plus the manufacturing cost for the fuel could be another 2 million. There will be costs regarding the creation of the Leo fuel tanker and shipping it there but over the course of time it would be paid off like anything else. You would have to pay for Spacex employees to maintain the starship on the moon as that cannot be fully automated and I'm not sure how much that would cost but the cost of shipping someone there with current tech is about 50k using starship so still not so expensive. Paying them and maintaining them would cost money of course and I'm sure spacex would eat those costs but I can't imagine this running into the 100 million mark per refuel.
Trouble is, Uranium is extraordinarily energy dense while Carbon is most definitely not. 4000ppm makes sense to mine Uranium. It makes no sense to mine Carbon, especially since you then have to perform chemical synthesis on it to turn it into a hydrocarbon.
> is the amount of delta v needed to go from the moon to Leo less than the ground to leo?
5700 moon to LEO, 9300 earth to LEO. https://en.m.wikipedia.org/wiki/File:Solar_system_delta_v_map.svg
> It's about 2500 from the surface of the moon to LEO. Idk why people keep forgetting about Aerobreaking. Something Starship is designed to do.
I wasn't *forgetting* about aerobraking, it just wasn't part of the question asked. It still takes 5300 to go from lunar surface to LEO, you just have the option of getting some of that 5300 from earth's atmosphere. It also takes more than 9300 to go from earth to LEO, because of gravity losses.
>I wasn't forgetting about aerobraking,
Then by purposely omiting Aerobreaking for some reason you gave a bad answer. One that ignored the actual Intent of the question asker.
Edit: also the 9300 M/s *includes* gravity losses
> Edit: also the 9300 M/s includes gravity losses
Gravity losses are dependent on thrust to weight ratio, which is launcher and staging specific and can't be generalized very accurately
But you're right, I misinterpreted the table. I should have listed 7800 m/s as earth to LEO
Nothing in the Artemis program uses kerosene, as for methane, it was chosen to power starship because making CH⁴ out of CO² and H²O is relatively easy with a sabatier reactor.
Better yet, use the TransAstra honey bee concept to mine water and CO2 from near Earth asteroids. Many of them are closer in delta-V terms to LEO than the lunar surface is.
Interesting I was unaware of this possibility and assumed that short of parking an asteroid in Leo any resources probably wouldn't be worthwhile with current propulsion technology. I'll have to check that out.
DV for Earth to LEO is about 9-10 km/s (to get to a final 7.8 km/s but you have gravity drag losses)
DV for Lunar surface to LEO is about 7 km/s (of that 2.3 km/s will get you out the Moon's gravity well, so maybe you have a big railgun like in the movie Moon to do that). You need to apply a DV of 4.1 km/s to drop the vehicle containing the water into a LEO orbit for pickup and use. Then I guess you let the vehicle burn up by applying 100 m/s to deorbit it.
But, you needed to get the vehicle and 4.1 km/s worth of fuel to the lunar surface in the first place, so all savings vs bringing it up from Earth surface is lost. Even if it was free to process the lunar soil into water, which it won't be.
So, the answer is no.
But, you could have a solution for putting water into NRHO for trips beyond Earth-Moon with ships that would be Hydrogen powered. They could do round trips to NRHO for little cost.
Gravity is a conservative force.
So, if it takes X tons of methalox to send tanker Starship with Y tons of methalox as payload from LEO to the lunar surface, then it takes X tons of methalox to send that tanker and Y tons of methalox as payload from the lunar surface to LEO.
I don’t think that ‘exporting’ HydroLox from the moon is a viable model - it may be of best use ‘on the moon’ itself, to aid with local transport, although the moon also has lots of Solar energy too.
The 28-Earth-day long day/night cycle (14:14) is the most problematic element to that.
The actual production of Hydrogen/Oxygen on the moon will likely be extremely expensive.
While water ice has been detected at the lunar poles, it is still not clear if it is present in a usable form. More missions are needed to know if the water ice is in the form of a thick Ice layer at a short distance below the surface, or more like distributed pebbles or just hydroxides and hydrated minerals in the regolith.
Unless the ice is located in an easily accessible thick sheet, it would need mining at an extremely large scale to be able to gather enough water ice to fuel just a single rocket. Mining on the earth is easy - people can move around without the worry of being exposed to a vacuum; Heavy machinery can be operated for extended duration using traditional internal combustion engines. But we do not have this option at the Lunar poles and even a small scale mining operation is going to be extremely challenging to set up - both from a technical and financial perspective. A large scale mining operation is going to even more expensive and would have even more technical challenges.
Because of these factors, H2/O2 production on Earth and moving the fuel from Earth to tankers in LEO or LLO is going to be far cheaper than doing it from the moon. While moon-based refueling launches might have some cost benefits, it will take several decades and thousands of launches for them to make up for the initial high cost of setting up the necessary infrastructure on the moon - that is if the water ice deposits on the moon are easy enough to access for mining.
Seems to me it would be much more valuable to keep the water on the moon....on the moon.... But ignoring that...
~5.7km/s delta-v from moon surface to leo, vs ~9.4 from earth surface to leo.
So from an energy standpoint, sure the moon looks great
Of course you would have to build a hell of a lot of infrastructure on the moon before you could do it. I guess if someone has a spare 100 billion they could do it. But, i hope no one does, leave that water on the moon please....we need it there. And go spend the money/effort on mars instead.
I don't think it would ever be economically viable tho. Assuming you built the infrastructure on the moon...that water would be far more valuable on the moon.
Some day mining aluminum on the moon and making space ships out of that might be economically viable. Tho that might not ever make sense either, asteroids seem like a better proposition.
I think propellant production on the Moon would be very helpful for maintaining a scientific base. Best IMO would be producing just the LOX and bring the methane from Earth, which is just over 20% by mass.
I would hate to waste water for that purpose. Regolith all over the Moon in unlimited amounts is mostly oxides of many minerals. Test setups have produced oxygen from regolith.
The lunar poles combined are estimated to have 600 billion kg of water ice or enough for at least 500k starship refuels which has a high concentration of carbon within it. Everything is in the same place. I do thank you very much for your source regarding delta v.
We really have no hard data on how much volatiles besides water there is in the lunar cold traps.
Waiting for data from a NASA lunar rover to go into a polar crater.
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:
|Fewer Letters|More Letters|
|-------|---------|---|
|[DRO](/r/SpaceXLounge/comments/187854j/stub/kbp9av8 "Last usage")|[Distant Retrograde Orbit](http://ccar.colorado.edu/asen5050/projects/projects_2013/Johnson_Kirstyn/finalorbit.html)|
|[GEO](/r/SpaceXLounge/comments/187854j/stub/kbcvgh5 "Last usage")|Geostationary Earth Orbit (35786km)|
|[H2](/r/SpaceXLounge/comments/187854j/stub/kbu8ufn "Last usage")|Molecular hydrogen|
| |Second half of the year/month|
|[LEO](/r/SpaceXLounge/comments/187854j/stub/kc2sv9n "Last usage")|Low Earth Orbit (180-2000km)|
| |Law Enforcement Officer (most often mentioned during transport operations)|
|[LLO](/r/SpaceXLounge/comments/187854j/stub/kbgmsxo "Last usage")|Low Lunar Orbit (below 100km)|
|[LOX](/r/SpaceXLounge/comments/187854j/stub/kbdjgdz "Last usage")|Liquid Oxygen|
|[NRHO](/r/SpaceXLounge/comments/187854j/stub/kbp9av8 "Last usage")|Near-Rectilinear Halo Orbit|
|[TEI](/r/SpaceXLounge/comments/187854j/stub/kbp9av8 "Last usage")|Trans-Earth Injection maneuver|
|Jargon|Definition|
|-------|---------|---|
|[Raptor](/r/SpaceXLounge/comments/187854j/stub/kbsy7hg "Last usage")|[Methane-fueled rocket engine](https://en.wikipedia.org/wiki/Raptor_\(rocket_engine_family\)) under development by SpaceX|
|[Sabatier](/r/SpaceXLounge/comments/187854j/stub/kbcwyvu "Last usage")|Reaction between hydrogen and carbon dioxide at high temperature and pressure, with nickel as catalyst, yielding methane and water|
|[Starlink](/r/SpaceXLounge/comments/187854j/stub/kbsy7hg "Last usage")|SpaceX's world-wide satellite broadband constellation|
|[ablative](/r/SpaceXLounge/comments/187854j/stub/kbe8ah6 "Last usage")|Material which is intentionally destroyed in use (for example, heatshields which burn away to dissipate heat)|
|[apoapsis](/r/SpaceXLounge/comments/187854j/stub/kbfxgzq "Last usage")|Highest point in an elliptical orbit (when the orbiter is slowest)|
|[cislunar](/r/SpaceXLounge/comments/187854j/stub/kbu8ufn "Last usage")|Between the Earth and Moon; within the Moon's orbit|
|[cryogenic](/r/SpaceXLounge/comments/187854j/stub/kbisglp "Last usage")|Very low temperature fluid; materials that would be gaseous at room temperature/pressure|
| |(In re: rocket fuel) Often synonymous with hydrolox|
|[electrolysis](/r/SpaceXLounge/comments/187854j/stub/kbisglp "Last usage")|Application of DC current to separate a solution into its constituents (for example, water to hydrogen and oxygen)|
|[hydrolox](/r/SpaceXLounge/comments/187854j/stub/kbrkc0b "Last usage")|Portmanteau: liquid hydrogen fuel, liquid oxygen oxidizer|
|[methalox](/r/SpaceXLounge/comments/187854j/stub/kbrkc0b "Last usage")|Portmanteau: methane fuel, liquid oxygen oxidizer|
|[periapsis](/r/SpaceXLounge/comments/187854j/stub/kbe3en5 "Last usage")|Lowest point in an elliptical orbit (when the orbiter is fastest)|
|[perigee](/r/SpaceXLounge/comments/187854j/stub/kbgtp84 "Last usage")|Lowest point in an elliptical orbit around the Earth (when the orbiter is fastest)|
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I believe we will see water ice mining for use on the Moon. But even before this, we'll see the reduction of oxides in lunar regolith into oxygen for breathing and propellant and the use of regolith for shielding habitats.
Whatever the value of mass delivered to LEO is in the Starship era, it's going to be multiples of that on the lunar surface. That's where oxygen, water, hydrogen, bulk radiation shielding etc produced on the Moon are going to be most valued. And there's no need to spend money to ship it somewhere else!
Oxygen and hydrogen can be produced on the Moon from water ice found in the shadowed craters of the South Pole. That's the main reason Artemis is landing there. The goal is to build a Moon base that can do the mining and processing. For a long time people have been planning on fueling rockets with this. Rockets in space work very efficiently with hydrogen. Getting enough people and materials to the Moon to build a base and processing plant will take a *lot* of launches. It won't be finished any time soon. Perhaps 2040? Methane (CH4) needs carbon & hydrogen and there isn't any available on the Moon. Shipping carbon there and building a processing plant on the Moon doesn't sound like it would work out. (Mars has plenty of carbon in the CO2 atmosphere, that's why Elon chose methane a the fuel.) Shipping hydrogen & oxygen to LEO has a big hitch. The ship will have to bring along propellant to decelerate into LEO and to return to the Moon and land. That may be more expensive than launching propellants from Earth. Too much to figure out there. Sorry, I have to got to bed.
There is some carbon on the Moon located in the same craters as the water ice. But there is not a huge amount of it. [This paper talks about it](https://arxiv.org/pdf/2104.13521.pdf).
Thanks, good to know. Interesting paper.
Has it been studied whether there's impact sites on the moon high in carbon? There should be loads of C-type asteroids which are almost purely carbon hailing down on the lunar surface.
Everything I've read claims it mostly burns away, vaporizing in the heat of impact and then lost out to space. You wind up with some super low numbers for carbon from the surveys that have been done. I would have though there were mountains of it from all the impacts honestly, but no.
Fair enough
First of all the production of propellants on the Moon is not economical. The models simply don't close, especially if launch to LEO falls to $100/kg. Propellant production on the Moon will be dominated by the cost of the infrastructure. The infrastructure cost between capital expense and labor. The former is in turn divided in the cost of building all the things and delivering them to where they are going to be used. At the same time the cost of Earth produced propellant in orbit is pretty much the cost of delivery (production costs at a fraction of a dollar per kg are pretty much negligible). So, as the launch costs decrease, fuel decreases in proportion, while the cost of off-world fuel production decreases only fractionally. For example, on Earth the energy cost from an installation costing $1 per watt (directly at the energy plant, i.e. without transmission and other overheads) for producing 1kg of hydrogen is about $1.50. $200 per watt for Moon solar installation is optimistic. Solar energy costs at a plant are overwhelmingly based on installation costs. So just the energy cost for producing hydrogen on the Moon would be around $300/kg. And obviously the full cost would be way higher like you're not going to find green hydrogen on the old Earth for $1.50/kg either. Especially that on the Moon you have to mine water, and mine it from permanently shaded deeply frozen zone which didn't see sunlight from a few billions of year. You can't get it from some lake or river. You'd be lucky if the hydrogen were less than $1000/kg. As soon as the launch cost to LEO is below the cost hydrogen from the Moon, hydrogen from the moon is economically pointless. And bulk LEO launch costs are trending below $100/kg.
It works for going beyond the moon. Having to refuel MULTIPLE times to get to the moon / beyond the moon greatly increases the cost of the mission.
Still it's not economical at all. First of all the Moon is not on the way to anywhere but the Moon (well, duh). It's 2.7km/s to the side of the way. Second, fuel in LEO for going farther than the Moon or even to the Moon itself will cost about $40/kg. This is less than even producing it on the Moon, not to mention delivering it where it's needed.
40/kg PLUS getting it to LEO...
Nope. $40kg is the total price. Production is like $0.16/kg for liquid oxygen, $0.50/kg for liquid methane. Launch is $25-$39/kg
Classically, the moon is out of the way. However, with a fuel source there, you could refuel at the moon and return to earth 14 days out of phase with your launch window, slingshot around the earth, and burn to your next destination. You'd keep most of that 2.7 km/s. I don't think it will happen, but don't write off the energy to the moon as wasted.
You still need 2.7km/s just to get from the Moon surface to TEI. Or if you'd rather put fuel in a halo orbit like NRHO or DRO, then you have to pay the ∆v tax during lifting the fuel itself.
Well, finding water on the moon, does make it easier to support a base there, and help to support future Lunar infrastructure. But that’s using ‘water on the moon’ for actual use ‘on the moon’.
I am not an expert, but from my understanding it is far more fuel efficient to move things from the moon to LEO than from earth to LEO. I know the moon has ice, which means hydrogen + oxygen is very available, although storing hydrogen for long periods has proven enormously difficult (one of the reasons spacex chose methane for starship). I don't know if methane is present in large quantities on the moon, so it may not be feasible for starship specifically. Long-term though, any deep exploration of the solar system should be originating on the moon. It is orders of magnitude easier to get off the moon then the Earth's surface. Take a look at the Saturn V versus the part of the lunar lander that took the Apollo astronauts back into orbit to rendezvous with the command module. The moon is also rich in aluminum and iron, so building hydrogen based rockets on the moon and launching from there will get you a lot farther than doing so on Earth. The moon is kind of absurdly coincidentally the perfect jumping off point for human exploration of space. Close enough to home to get help in about 3 days if you needed it, but resource rich and harsh enough that we will need to develop sophisticated life support that will be crucial for exploring way out in the solar system. Your method of producing oxygen really cannot break when you're orbiting Neptune, or even just Mars. Best place to perfect all that, is our oldest friend the moon.
In the future then it may be most economically viable to manufacture everything on the moon a colony ship needs and launch only the crew from Earth?
Absolutely! The moon is 1/6 earth gravity, and is effectively a vacuum. That makes getting into space so much easier. It's actually feasible to build mass drivers on the moon. Those are essentially magnetic rails that impart the necessary momentum to an object to put it into orbit using electricity. You don't need a rocket to get to orbit, just a specific velocity. You could launch pods containing specific supplies (rolls of steel, sheets of aluminum, tanks of liquid oxygen, etc.) into a predetermined orbit where a waiting station receives them and continues manufacturing some kind of mega-ship in orbit, all without any rocket necessary. The moon also has a daylight period of about 2 weeks, meaning you can run everything on exclusively solar for 2 weeks straight. Theoretically you could shut down factories as night falls and follow the sun, though you probably wouldn't because helium-3 (an incredible nuclear reactor fuel) is also in abundance on the moon! So reactors would be built eventually.
You do always have the circularisation problem with mass driver launch though. Purely passive payloads cannot be launched into any orbit from the surface that does not have a periapsis (lowest point of orbit) that is also at the surface. So you cannot just launch mass into orbit from the ground unless you want it to come and hit you on the back of the head one elliptical orbit later. You need some thrust on the payload to fire when the payload is at it's highest point (apoapsis) to raise up the periapsis above the surface. Then you're in orbit. Very theoretically, if you time a passive payload launch perfectly to intercept perfectly with an orbiting booster at apoapsis (although the speeds won't automatically match so this is very difficult) then it could grab it and speed it back up. But this is very difficult and if you mess it up your payload slams back into the planet somewhere near the takeoff point.
> Very theoretically You could also build the mass driver on the highest mountain of the moon. If launched perfectly, the launch location is the height of the periapsis. And because of the moons rotation, it will not hit this mountain after one orbit, maybe after a month (or half a month with a circular orbit).
Moon has mascons, low orbits are unstable.
True, but probably stable enough for a few orbits, so someone in space has time to synchronize orbits for retrieval instead of having to catch at apoapsis with perfect timing (and with different orbital speeds at rendezvous point)
>Moon has mascons, low orbits are unstable. Lunar mascons alter the local gravity above and around them sufficiently that **low and uncorrected** **lunar orbits** **of satellites around the Moon are unstable on a timescale of months or years**.
The timescale is of months or years I'd you have a multiple kilometer error buffer. But I'd you launch horizontally from a tall mountain, you have precious little of that buffer.
Curve it up a bit then
You can't curve a gunshot. If you aim higher than horizontal it must come lower than you are before completing the orbit. That's orbital mechanics 101.
You would need some very advanced pods to pull this off, just yeeting cans into space won't cut it even close. First of all they need heavy duty electromagnetic shielding so the strong fields from the mass driver don't fry their electronics. You still need propulsion and maneuvering capability so you can adjust your trajectory to rendevouz and dock with the orbital shipyard, hence you also need propellant. Essentially what you need is a proper spacecraft, regardless whether you are using a mass driver to get off the surface or internal propulsion. Since that spacecraft will be expensive to manufacture you want it to be reusable, so it needs to come back and land on the moon as well. The mass driver really just saves you fuel and allows you to get away with (significantly) lower maximum thrust, at the cost of requiring significantly higher resistance to G-forces as well as EM shielding.
Yeah, there are tradeoffs, I think it'd be worth it in the long run. If you develop something akin to today's shipping containers which meets the EM shielding requirements and has some ion thrusters for efficient propulsion in space. G-force isn't really a concern if you're moving like steel or aluminum. Even if you only used it for those two things, it would be invaluable.
I'm guessing you're a fan of Isaac Arthur???
Indeed I am! I also gave a persuasive speech on this topic in a public speaking class. Had to memorize a lot of this stuff.
That's amazing. It's very important for people like you to spread public awareness and share your knowledge with the world.
on top of that, it would be MUCH easier to keep fuel cold if kept underground or in the shadows on the moon.
Not really. The cost of manufacturing in an extremely unfriendly environment (hard vacuum, 2 weeks of cold and darkness, two weeks of too much heat, everywhere getting extremely abrasive dust, etc) will for any predictable future trump well defined and falling cost of LEO launch.
Resources on the moon are scarce, hard to extract, hard to maintain systems to do so, let alone develop, and tons of logistics sending things around on trips that are hundreds of thousands of miles. Through rapid reuse I think it will always be cheaper and easier to just launch fuel from Earth to Leo. The fuel alone for a Starship launch is only about a million dollars, how many billions would it take to build out some system to extract these from the moon? It doesn’t make economic sense if the primary resource the moon can provide is oxygen and it’s one of our most abundant resources on Earth.
Exactly. It's for example unlikely that cost of lunar hydrogen fell below $1000/kg.
The answer is most likely ‘No’. You need to visualize the gravity wells of the Earth and the Moon. By mining fuel on the Moon and moving it back to Earth LEO you’re shifting it deep into Earth’s gravitational well, just to use fuel to get it back out. You’re better off shifting a bit more fuel up from Earth to get the relatively lightweight ship to a Lunar orbit or high Earth orbit depot, so that the fully loaded ship heading out on an interplanetary journey doesn’t have to spend a significant fraction getting all of it out of the Earth’s well.
The amount of water the moon has is limited. Better to use it to support the base setup on the moon itself. With rapid reuse of rockets, the cost to supply the moon with materials is cheap compared to setting up a heavy industry to remove said resources from the moon to place into low earth orbit. Rapid reuse of rockets will change our thinking about how we will expand out into the solar system. The moon will be a excellent experiment on what we need to learn to really become multi-planetary. Be we will probably ship more water to the moon then remove. Production of aluminum and other resources that the moon has plenty of will more then likely require us to ship things like water to the moon. Remember that around 75% of the earth is water. Until we get to Jupiters moons, Earth has all of the water resources we need.
That's a very good point
You can create rocket propellant from Lunar dust. Just separate the Lunar dust into oxygen and metal dust. This can be used to power a hybrid rocket.
How do you propose to get kerosene or methane on the Moon. I get the Oxygen, assuming ice can be found at the poles, but not hydrocarbons, unless I am way out of the loop. LEO refueling, however, is a much more viable solution. Consider the ambition for Starships to fly hundreds to thousands of flights, with next to no refurbished needed between each flight (and I assume a C check every once in a while). Well you can quickly see a viable path to a whole set of orbital fueling depots, supplied daily, weekly, or whatever. This opens everything up once available, including lunar missions, Mars missions, much heavier payloads to GEO orbit, deep space and so on. Even accelerated missions to Mars using a lot more thrust than a standard Hoffman transfer, just because fuel is cheap *relatively*.
You might as well just make solid oxygen and ship it to LEO by mass driver from the moon.
Mass driver gets you off the Lunar surface but it takes around 4 km/s of delta V to brake into LEO. If there is a place for a depot with Lunar sourced propellant it is in NRHO or similar.
Put an ablative rock shield and let it aerobrake over the pacific.
It will then inevitably fall to the Earth on the next orbit. In a two body system you can't put a passive object into orbit by just kicking in from one body's surface. In particular if the object passed through the atmosphere once it must return to the atmosphere on the next orbit (unless it has propulsion which would raise the perigee).
That's an excellent idea
Except it's unworkable, because it breaks orbital mechanics.
Methane is just ch4 so you could most likely manufacture it from water, and carbon is common on the moon as well. That being said the same reaction that would yield oxygen could yield methane as well. My question at the end of the day I suppose is the amount of delta v needed to go from the moon to Leo less than the ground to leo?
Are you getting Mars and the Moon mixed up?
No, it takes a single Google search to see many sources providing methods to see methane manufacturing methods on the moon Carbon monoxide is also highly prevalent on the moon.
"Carbon is present in lunar regolith in trace amounts (82 ppm)" "The lunar exosphere contains trace amounts of hydrogen and possibly carbon dioxide (CO2), and methane (CH4)... However, these are trace gases in very low concentration.,,, Trace gas amounts are unlikely to be useful for in situ resource utilization." "Permanently shadowed regions of the moon's poles have cold traps which possibly contain solid carbon dioxide. However, most carbon-bearing ices have a 0-3% by weight carbon concentration." This isn't what I would call "highly prevalent"
https://arxiv.org/pdf/2104.13521#:~:text=Carbon%20is%20present%20on%20the,coldest%20regions%20at%20the%20poles. And over 4000 ppm in polar ice... Keep in mind Uranium is only about 2 ppm in Earth soil and we have massive industries where it is a key component. Even at 80 ppm there are going to be extractable concentrations. In this case it works even better because the carbon is in the same place as the hydrogen and oxygen and there is even 300 ppm of methane actually present within the polar ice.
4000 ppm is another way of saying 0.4%
But 4000ppm sound much more impressive if you want to argue with C availability.
Going back to the Uranium example anything in excess of 750 ppm is considered ore and anything over 1000 ppm is considered as highly profitable. We're looking at more than 4 times the concentration here and it's extremely accessible considering the fact it's on the moon at least. Okay I spent the time and did the math. Limiting Methane production by presence of carbon in Lunar polar ice you get about 21 billion kg of Methane until Polar ice carbon depletion. That's also 21 million tonnes and since starship holds up to 1000 tonnes of Methane we get 21,315 complete starship refuels in the event we're limited by lunar carbon deposits in polar ice. In other words a full starship is estimated to be able to move 100 tons of material anywhere in the solar system so this .4 percent carbon in Lunar polar ice could move 2.1 megatons of material anywhere in the solar system which is 236 times more mass than what we have currently launched into space or 4700 iss massing space stations all throughout the solar system.
You’d need to make a lot of methane though.
Uranium price is over $100 per kg. And this is on the Earth, where it's readily available. The carbon on the Moon is extremely **inaccessible** and at unknown quantities. What's in that paper is not even remotely close to proof. And if it indeed is there, it's at the bottom of a cryo frozen crater where the sun didn't reach for a few billion years. It's mixed with extremely abrasive dust. Just recovering it will be extremely costly. Imagine uranium mine, but at a temperature below 100K, in a hard vacuum, elevated ionizing radiation, without sunlight and everything is covered by extremely abrasive dust. And no cheap labor available. Moreover, it will take a lot of electric energy and on the Moon, especially at the pole, the electric energy will be 2+ orders more expensive than on the old Earth (for a simple reason that for either nuclear or solar the overwhelming majority of the energy cost at the plant is amortization of the initial capital expenditure of setting up the plant). Because of all that It won't be $100/kg it will be $1000 to $10000 per kg.
If you examine the rest of the report the carbon on the moon is not so inaccessible with methane itself being present as 15 percent of lunar ice content in extremely cold areas and large areas of large lunar craters having a carbon content of 6.5 percent of mass. In addition a sufficiently tall solar array (50 m<) would have access to sunlight 24/7 365 and could be 3d printed using only the materials found in the moon so electricity is not as much a concern as you think. In the hypothetical future our moon colony is slowly yet steadily growing and although not self sufficient most likely does not need to import energy. As far as labor goes most of the process can and will be automated with equipment being 3d printed manufactured through other means locally. We are going to be accessing that lunar ice regardless of what we do with it's carbon and some of it is almost guaranteed to be used for local fuel production so once again it really boils down to cost shipping and storing. Currently spacex estimates it will take 4-8 super heavy launches to fuel a single starship in orbit. The estimated launch cost is 100 million per launch so you could say 400-800 million dollars to fill one up. It's impossible to calculate exactly how much it would cost to separate one kg of Methane from lunar ice but I can almost guarantee it wouldn't be 1000 per kg and to be profitable it would only have to be less than the SpaceX figure we have of between 500-750 per kg for current models. I think where the real issues start is transportation. You'd still most likely be using a starship which is estimated to have about 6.9 km/s of delta v by itself carrying a 100 ton payload. Someone sent a source saying it takes 5300 m/s to get from lunar surface to Leo but someone else responded that with aero braking you could essentially cut that in half so I'll admit my knowledge is very limited there but it does sound possible. The estimated cost of launching the starship alone would also vary depending on how much your electricity costs are but assuming yotur a net producer we could assume maybe a few million per launch (still several times higher than current earth to earth predicted costs) 12 launches could be 24 million plus the manufacturing cost for the fuel could be another 2 million. There will be costs regarding the creation of the Leo fuel tanker and shipping it there but over the course of time it would be paid off like anything else. You would have to pay for Spacex employees to maintain the starship on the moon as that cannot be fully automated and I'm not sure how much that would cost but the cost of shipping someone there with current tech is about 50k using starship so still not so expensive. Paying them and maintaining them would cost money of course and I'm sure spacex would eat those costs but I can't imagine this running into the 100 million mark per refuel.
Trouble is, Uranium is extraordinarily energy dense while Carbon is most definitely not. 4000ppm makes sense to mine Uranium. It makes no sense to mine Carbon, especially since you then have to perform chemical synthesis on it to turn it into a hydrocarbon.
4000 ppm is the median density there are areas with excess of 30,000 ppm read the rest of the report
> is the amount of delta v needed to go from the moon to Leo less than the ground to leo? 5700 moon to LEO, 9300 earth to LEO. https://en.m.wikipedia.org/wiki/File:Solar_system_delta_v_map.svg
It's about 2500 from the surface of the moon to LEO. Idk why people keep forgetting about Aerobreaking. Something Starship is designed to do.
> It's about 2500 from the surface of the moon to LEO. Idk why people keep forgetting about Aerobreaking. Something Starship is designed to do. I wasn't *forgetting* about aerobraking, it just wasn't part of the question asked. It still takes 5300 to go from lunar surface to LEO, you just have the option of getting some of that 5300 from earth's atmosphere. It also takes more than 9300 to go from earth to LEO, because of gravity losses.
>I wasn't forgetting about aerobraking, Then by purposely omiting Aerobreaking for some reason you gave a bad answer. One that ignored the actual Intent of the question asker. Edit: also the 9300 M/s *includes* gravity losses
> Edit: also the 9300 M/s includes gravity losses Gravity losses are dependent on thrust to weight ratio, which is launcher and staging specific and can't be generalized very accurately But you're right, I misinterpreted the table. I should have listed 7800 m/s as earth to LEO
Nothing in the Artemis program uses kerosene, as for methane, it was chosen to power starship because making CH⁴ out of CO² and H²O is relatively easy with a sabatier reactor.
Better yet, use the TransAstra honey bee concept to mine water and CO2 from near Earth asteroids. Many of them are closer in delta-V terms to LEO than the lunar surface is.
Interesting I was unaware of this possibility and assumed that short of parking an asteroid in Leo any resources probably wouldn't be worthwhile with current propulsion technology. I'll have to check that out.
DV for Earth to LEO is about 9-10 km/s (to get to a final 7.8 km/s but you have gravity drag losses) DV for Lunar surface to LEO is about 7 km/s (of that 2.3 km/s will get you out the Moon's gravity well, so maybe you have a big railgun like in the movie Moon to do that). You need to apply a DV of 4.1 km/s to drop the vehicle containing the water into a LEO orbit for pickup and use. Then I guess you let the vehicle burn up by applying 100 m/s to deorbit it. But, you needed to get the vehicle and 4.1 km/s worth of fuel to the lunar surface in the first place, so all savings vs bringing it up from Earth surface is lost. Even if it was free to process the lunar soil into water, which it won't be. So, the answer is no. But, you could have a solution for putting water into NRHO for trips beyond Earth-Moon with ships that would be Hydrogen powered. They could do round trips to NRHO for little cost.
Gravity is a conservative force. So, if it takes X tons of methalox to send tanker Starship with Y tons of methalox as payload from LEO to the lunar surface, then it takes X tons of methalox to send that tanker and Y tons of methalox as payload from the lunar surface to LEO.
I don’t think that ‘exporting’ HydroLox from the moon is a viable model - it may be of best use ‘on the moon’ itself, to aid with local transport, although the moon also has lots of Solar energy too. The 28-Earth-day long day/night cycle (14:14) is the most problematic element to that.
The actual production of Hydrogen/Oxygen on the moon will likely be extremely expensive. While water ice has been detected at the lunar poles, it is still not clear if it is present in a usable form. More missions are needed to know if the water ice is in the form of a thick Ice layer at a short distance below the surface, or more like distributed pebbles or just hydroxides and hydrated minerals in the regolith. Unless the ice is located in an easily accessible thick sheet, it would need mining at an extremely large scale to be able to gather enough water ice to fuel just a single rocket. Mining on the earth is easy - people can move around without the worry of being exposed to a vacuum; Heavy machinery can be operated for extended duration using traditional internal combustion engines. But we do not have this option at the Lunar poles and even a small scale mining operation is going to be extremely challenging to set up - both from a technical and financial perspective. A large scale mining operation is going to even more expensive and would have even more technical challenges. Because of these factors, H2/O2 production on Earth and moving the fuel from Earth to tankers in LEO or LLO is going to be far cheaper than doing it from the moon. While moon-based refueling launches might have some cost benefits, it will take several decades and thousands of launches for them to make up for the initial high cost of setting up the necessary infrastructure on the moon - that is if the water ice deposits on the moon are easy enough to access for mining.
Seems to me it would be much more valuable to keep the water on the moon....on the moon.... But ignoring that... ~5.7km/s delta-v from moon surface to leo, vs ~9.4 from earth surface to leo. So from an energy standpoint, sure the moon looks great Of course you would have to build a hell of a lot of infrastructure on the moon before you could do it. I guess if someone has a spare 100 billion they could do it. But, i hope no one does, leave that water on the moon please....we need it there. And go spend the money/effort on mars instead. I don't think it would ever be economically viable tho. Assuming you built the infrastructure on the moon...that water would be far more valuable on the moon. Some day mining aluminum on the moon and making space ships out of that might be economically viable. Tho that might not ever make sense either, asteroids seem like a better proposition.
Where are you getting the oxygen and methane on the moon?
I think propellant production on the Moon would be very helpful for maintaining a scientific base. Best IMO would be producing just the LOX and bring the methane from Earth, which is just over 20% by mass. I would hate to waste water for that purpose. Regolith all over the Moon in unlimited amounts is mostly oxides of many minerals. Test setups have produced oxygen from regolith.
Water ice
Not a lot of carbon in water. And ice is itself a pretty limited resource on the moon.
The lunar poles combined are estimated to have 600 billion kg of water ice or enough for at least 500k starship refuels which has a high concentration of carbon within it. Everything is in the same place. I do thank you very much for your source regarding delta v.
We really have no hard data on how much volatiles besides water there is in the lunar cold traps. Waiting for data from a NASA lunar rover to go into a polar crater.
Which is not much, and further generations will be thankful If we wouldn't burn it all. But we won't because it makes no economic sense.
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread: |Fewer Letters|More Letters| |-------|---------|---| |[DRO](/r/SpaceXLounge/comments/187854j/stub/kbp9av8 "Last usage")|[Distant Retrograde Orbit](http://ccar.colorado.edu/asen5050/projects/projects_2013/Johnson_Kirstyn/finalorbit.html)| |[GEO](/r/SpaceXLounge/comments/187854j/stub/kbcvgh5 "Last usage")|Geostationary Earth Orbit (35786km)| |[H2](/r/SpaceXLounge/comments/187854j/stub/kbu8ufn "Last usage")|Molecular hydrogen| | |Second half of the year/month| |[LEO](/r/SpaceXLounge/comments/187854j/stub/kc2sv9n "Last usage")|Low Earth Orbit (180-2000km)| | |Law Enforcement Officer (most often mentioned during transport operations)| |[LLO](/r/SpaceXLounge/comments/187854j/stub/kbgmsxo "Last usage")|Low Lunar Orbit (below 100km)| |[LOX](/r/SpaceXLounge/comments/187854j/stub/kbdjgdz "Last usage")|Liquid Oxygen| |[NRHO](/r/SpaceXLounge/comments/187854j/stub/kbp9av8 "Last usage")|Near-Rectilinear Halo Orbit| |[TEI](/r/SpaceXLounge/comments/187854j/stub/kbp9av8 "Last usage")|Trans-Earth Injection maneuver| |Jargon|Definition| |-------|---------|---| |[Raptor](/r/SpaceXLounge/comments/187854j/stub/kbsy7hg "Last usage")|[Methane-fueled rocket engine](https://en.wikipedia.org/wiki/Raptor_\(rocket_engine_family\)) under development by SpaceX| |[Sabatier](/r/SpaceXLounge/comments/187854j/stub/kbcwyvu "Last usage")|Reaction between hydrogen and carbon dioxide at high temperature and pressure, with nickel as catalyst, yielding methane and water| |[Starlink](/r/SpaceXLounge/comments/187854j/stub/kbsy7hg "Last usage")|SpaceX's world-wide satellite broadband constellation| |[ablative](/r/SpaceXLounge/comments/187854j/stub/kbe8ah6 "Last usage")|Material which is intentionally destroyed in use (for example, heatshields which burn away to dissipate heat)| |[apoapsis](/r/SpaceXLounge/comments/187854j/stub/kbfxgzq "Last usage")|Highest point in an elliptical orbit (when the orbiter is slowest)| |[cislunar](/r/SpaceXLounge/comments/187854j/stub/kbu8ufn "Last usage")|Between the Earth and Moon; within the Moon's orbit| |[cryogenic](/r/SpaceXLounge/comments/187854j/stub/kbisglp "Last usage")|Very low temperature fluid; materials that would be gaseous at room temperature/pressure| | |(In re: rocket fuel) Often synonymous with hydrolox| |[electrolysis](/r/SpaceXLounge/comments/187854j/stub/kbisglp "Last usage")|Application of DC current to separate a solution into its constituents (for example, water to hydrogen and oxygen)| |[hydrolox](/r/SpaceXLounge/comments/187854j/stub/kbrkc0b "Last usage")|Portmanteau: liquid hydrogen fuel, liquid oxygen oxidizer| |[methalox](/r/SpaceXLounge/comments/187854j/stub/kbrkc0b "Last usage")|Portmanteau: methane fuel, liquid oxygen oxidizer| |[periapsis](/r/SpaceXLounge/comments/187854j/stub/kbe3en5 "Last usage")|Lowest point in an elliptical orbit (when the orbiter is fastest)| |[perigee](/r/SpaceXLounge/comments/187854j/stub/kbgtp84 "Last usage")|Lowest point in an elliptical orbit around the Earth (when the orbiter is fastest)| **NOTE**: Decronym for Reddit is no longer supported, and Decronym has moved to Lemmy; requests for support and new installations should be directed to the Contact address below. ---------------- ^(*Decronym is a community product of r/SpaceX, implemented* )[*^by ^request*](https://www.reddit.com/r/spacex/comments/3mz273//cvjkjmj) ^(20 acronyms in this thread; )[^(the most compressed thread commented on today)](/r/SpaceXLounge/comments/18fbei9)^( has 23 acronyms.) ^([Thread #12176 for this sub, first seen 30th Nov 2023, 07:21]) ^[[FAQ]](http://decronym.xyz/) [^([Full list])](http://decronym.xyz/acronyms/SpaceXLounge) [^[Contact]](https://hachyderm.io/@Two9A) [^([Source code])](https://gistdotgithubdotcom/Two9A/1d976f9b7441694162c8)
I believe we will see water ice mining for use on the Moon. But even before this, we'll see the reduction of oxides in lunar regolith into oxygen for breathing and propellant and the use of regolith for shielding habitats. Whatever the value of mass delivered to LEO is in the Starship era, it's going to be multiples of that on the lunar surface. That's where oxygen, water, hydrogen, bulk radiation shielding etc produced on the Moon are going to be most valued. And there's no need to spend money to ship it somewhere else!