Apparently McMurdo Station needs 7000 tons of assorted supplies each year. Assuming Moon Base runs on a similar scale, that's an initial annual budget of $7bn just for the shipping.
This assumes air and water are solved problems and don't need to be shipped.
Note that oxygen != air. 100% oxygen atmospheres are not a good idea for extended stays.
Nitrogen is not common on the Moon. Nor is carbon (for filtering or other organic applications.)
It's not easy to imagine a lunar base generating >$7bn of returns every year. Apart from space tourism, there isn't a whole lot you can do/build/sell on a moon base that has more value on Earth than it would cost to transport back here.
Of course you could argue Science, and that's fair enough. But literally all the commercial arguments I've seen have been "Something will no doubt appear" - which is possibly not going to win over rational investors.
> Apparently McMurdo Station needs 7000 tons of assorted supplies each year. Assuming Moon Base runs on a similar scale, that's an initial annual budget of $7bn just for the shipping.
This would never be a real scenario. McMurdo supply runs are not designed for such high transportation costs. With such transportation cost expectations you'd be pressed to lower the mass of the supplies in the first place so that the sum of the cost of preparing the supplies and the cost of transferring them were minimized. You need to compare two Pareto optima completely, not just one axis of them.
Yeah, but flipside, you're probably gonna need things on the Moon that you wouldn't for a terrestrial base. I think it's fair to assume that the $7bn a year figure is just a very rough number, but still a useful one for understanding just how outrageously expensive it would be to maintain a Moon base.
You kind of have a model of a lunar space station in the form of ISS. That's definitely not 7000 tonnes of supplies for a base. Maybe something like 15 tonnes per year or so.
ISS currently has 7 people on it, McMurdo Station varies between 250 and 1258. I don’t know the mass/year of the ISS resupply missions, neither including or excluding orbit reboosting fuel which a moon base can clearly ignore.
I'll take a look at the exact figures, but assuming the average number of people at McMurdo is 750, it's 9 tonnes per person per year, whereas in the case of ISS, it should be something like one third of this number per crew member at worst. Clearly they've already minimized the necessary supplies somewhat already.
A big difference is the ISS uses 24/7 solar where McMurdo can’t. Unfortunately powering a moon base is quite difficult do to the month long day night cycle, so it’s going to need nuclear or a lot of batteries.
That said, the ISS doesn’t do long distance missions dropping off equipment etc the way McMurdo and presumably any Moon Base would. So, the ISS isn’t that great of a model.
ISS doesn't use "24/7 solar". Insolation of the ISS depends on the beta angle and therefore ISS crucially relies on batteries for its continuous operation.
Here's the thing about a lunar base on the south pole of the Moon: It's assumed that it would manufacture its own propellant from local resources (water). That means that you're already storing electricity electrochemically because that's exactly how you make propellant from water. But that means that it's just a small leap to make the storage tanks slightly larger and siphon off a small portion of the hydrogen and oxygen to generate "baseline" electricity for the station. You already have all the equipment anyway, why not just add a fuel cell? We can do small fuel cells more easily than we can do small reactors anyway. And even just one spare cubic meter of your hydrogen tank provides you with 1.3 MWh of electricity. One extra meter of length on a 4.5 diameter tank provides you with over 10 MWh of electricity.
> You already have all the equipment anyway, why not just add a fuel cell?
According to the blog post, the dry mass of the fuel cells would mass similar to LiIon of the same energy storage capacity, not counting the mining equipment to get the lunar water.
That makes no sense whatsoever; fuel cell mass scales with power output, not with system capacity. Extra capacity incurs just slightly bigger tanks. No serious study I've seen assumes that long-duration storage (~100h or more) has fuel cells heavier than batteries. The last paper I've seen had batteries twice as heavy as the whole fuel cell system. I may try to find it again.
You need a part of the system anyway so you can't count those parts (water tanks, hydrogen tanks, oxygen tanks, electrolyzer) into any of the power options. They will be there regardless of whether you want them or not.
Also I've noticed that despite of what ben_w claims the article says, the article still assumes 100 kWh/t for a battery system and 1 MWh/t for a fuel cell system. So it doesn't really say that "the dry mass of the fuel cells would mass similar to LiIon of the same energy storage capacity", otherwise the numbers would be in the opposite order.
Right next to where it suggests 1 MWh/t “For the sake of argument”, it says:
"""Even using Lunar water, the mass of the cells, condensers, electrolysers, power electronics, storage tanks, and heat exchangers is comparable a Lithium-ion battery, while the round trip efficiency is much lower. And that’s not even including the mass overhead for mining lunar water!"""
Yes, but that makes no sense. Partly because as I said, lots of those components will be mandatory anyway so they should count into the fuel cell system at best only partially, and partly because pretty much the only part that scales with capacity is the tanks anyway. The rest scales overwhelmingly with average power instead.
Due to shipping and redundancy concerns redundant tanks are used to expand storage. So, the dry mass of tanks should scale nearly linearly with the total amount of water, hydrogen, and air stored.
Nobody said they don't. But 1) that doesn't make the fuel cells bigger (so the "similar dry mass of the fuel cells to batteries of a given capacity" is a category error), and 2) the additional tank mass is very mild. We can for example store 20.8 tonnes of hydrogen/oxygen mixture in a ~2 tonne tank. We know this because the Centaur stage does it. And those two tonnes of tankage correspond to ~50 MWh of electricity generated by a fuel cell. That's almost 300 tonnes worth of batteries in the form of 23 tonnes of mass, 21 of which might even not need transportation from Earth. Potentially up to a 100:1 win for Team Fuel Cells! ("Only" ~10:1 if you do carry water from Earth, but that's still substantial.)
Sure, dry mass of fuel cells vs dry mass for fuel cells vs total mass need for fuel cells.
Also, that’s just the start. Team fuel cells are also dramatically lower efficiency so you need a extra solar panels and all the associated equipment with that. Which again scales linearly with energy demands.
For non tracking panels at 100% efficiency and 200W/kg assuming an optimistic 1/2 of total weight for solar collection is panels runs around 50 kg per MWh per month on the moon.
Batteries at ~90% bump that to 55kg/MWH. Fuel cells at ~30% bump that to ~170 kg or another 110kg /MWh, not that significant but still important.
How does panel efficiency go into this? Those 200 W/kg are post-conversion, so whatever efficiency they have is already included.
> assuming an optimistic 1/2 of total weight for solar collection is panels
What does that even mean? 200 W/kg is system efficiency, so not just cells but all the structures involved.
> runs around 50 kg per MWh per month on the moon.
I don't get it. "MWh per month" is 114 watts. A 50 kg array at 200 W/kg has 10 kW peak. At the south pole, a non-tracking unifacial horizontally mounted and elevated array will have at least a ~30% capacity factor, a bifacial array will have a ~60% capacity factor. That's 3 kW or 6 kW on average, respectively, far from your 114 watts.
EDIT: Should have really been 1.4 kW instead of 114 watts - I calculated with 1 MWh per year by a mistake. Still a substantial difference from 3/6 kWh.
> Fuel cells at ~30%
A round-trip from a fuel-cell system will be at ~40%. Maybe ~50% if you use top equipment. But even bog-standard fuel cells are at ~50-55% (LHV) efficiency and bog-standard PEM electrolyzers are at ~80% efficiency, which should give you no less than a 40% round-trip.
It doesn’t but a measure of output from solar panels ignores the storage efficiency which is what we care about here.
> 200w/kg is system efficiency.
You listed that as the panels in your post.
First actual array output falls over time. Whatever it would be new is irrelevant you scale for how long it’s in use. Panels on the moon need to be mounted at an appropriate angle for maximum efficiency, cooling, they need wires to move electric from the panel to your power conversion, electronics to handle that power etc. You also get losses from lunar dust, etc. Simply saying all that doubles weight is a reasonable ballpark.
Don’t forget the moon is dealing with days of full sun panels need to maintain low temperatures for efficiency and you can’t just dump all that heat into the moon.
> I don’t get it
A 50kg array consisting of 25kg of solar panels, at 30% efficiency produces: 25 different 0.2kw panels for 30 percent of the time over 28 days times 24 hours = 25 * 0.200kw * 0.30 * 28 * 24h = 1008 kWh or 1.008 MWh.
Edit: 1.4kW * 28 days * 24h/day = 940 kWh or 0.94 MWh.
> A round-trip from a fuel-cell system will be at ~40%.
I have yet to read about an actual working system over 30% water to hydrogen to water. Do you have any citations or is this assuming some unknown breakthrough?
As dredmorbius points out, the ISS gets solar every hour of every day, so it really is 24/7. What it’s not is 60/24/7, because up to ~45 minutes of each hour may be in earths shadow.
I may not be a native English speaker, but Wikipedia tells me that "In commerce and industry, 24/7 or 24-7 service (usually pronounced "twenty-four seven") is service that is available at any time and usually, every day ... Synonyms include round-the-clock service (with/without hyphens), especially in British English, and nonstop service".
I struggle to fit "at some times during every hour" into this definition. If there's a 24/7 shop, I definitely don't expect not being able to enter it at some times, or even not being able to enter it 75% of the time.
In practice it’s common to use similar terminology for intermittent services.
For example a subway train might only be running every 30 minutes but it still lists hours of operation. The hotel help desk might not have someone there every second, but theirs a difference between someone putting up a “be back in 15 minutes sign” when their on a bathroom break rather than a closed sign when they are leaving for the day. Informally, the existence of a modest wait doesn’t preclude 24/7 service.
I definitely don't picture a 24/7 service as waiting up to 45 minutes every hour. By that time you're operating six hours out of every twenty four. You might not even be able to advertise yourself as 24/7 at that point in some places.
> For example a subway train might only be running every 30 minutes but it still lists hours of operation.
But that's a train. It never runs every single moment, so that doesn't make the times with once-per-30-minutes trains different from the times with once-per-10-minutes trains. On the other hand, if it's for example a grocery store, you definitely do expect being able to enter at any moment and purchase something if it advertises itself as "24/7" or "nonstop".
As a native English speaker, I agree with your assessment of “24/7”; linguistics aside, the core point of the argument is (or should be) that ISS power cycle is 90 minutes whereas a moon base would be 28 days, unless you can get power from the sun side to the dark side.
I’m unclear why the blog post is saying this is difficult, as it should be fairly straightforward to make aluminium cables in-situ and just leave them exposed on the surface, the atmospheric pressure on the moon is far lower than the minimum of the graphs on the linked Paschen's law Wikipedia page. (I’m not a physicist, there is a high chance I’m overlooking something any vacuum engineer would consider obvious).
If you're mentioning the cycle lengths, the ISS actually has it worse relatively to the length of its cycle than a south pole base on the Moon would have it since ISS can spend up to around 40% of its time in Earth's shadow whereas lunar night can be as little as several days long on some places of the south pole. And if you elevate the solar array by as little as several meters, I believe I saw some papers predicting a period without power as short as 2.5-3 days or so. So rather than a ~500:1 ratio of storage difficulty, it's at least improved to ~100:1 or so. Still fairly bad but not as bad as the simple cycle length ratio would suggest.
The notion of connecting several places with cables is a nice one, and also a neat optimization problem. We should be able to calculate the immediate power curves in different places. Finding a minimum cost combination could be the topic for an interesting study. Long-term, this is definitely what you'd want to do.
> you definitely do expect being able to enter at any moment and purchase something if it advertises itself as "24/7"
But what’s an acceptable delay before purchase. I have definitely spent more than 45 minutes waiting in the line for events etc while their currently open.
It’s all kind of moot as it’s clear what I meant is exactly the underlying reality, but I can see why you object.
So that’s 1% of the US military budget. Double it and it seems affordable? What is the return on aircraft carriers 8-11, when the next most powerful nation has 1.
The problem is that if you want one aircraft carrier on active deployment, you really need three physical carriers. One on patrol, one about to go on/off patrol, and another in maintenance. So really 11 carriers lets you actively patrol 3, maybe 4 zones. And again, that's just one carrier in that area, if you can to concentrate resources you might get a few more there, but then you're delaying maintenance/training. If anything the US needs more carriers as recent years have taught the navy.
>If anything the US needs more carriers as recent years have taught the navy.
This is an insane position. The US already has a bigger navy than the next 10 great navies combined, 8 of which are close allies. There has never in the history of the world been such a huge power imbalance (the British Empire at its height maintained a navy twice the size of its two biggest rivals). And you think they need a bigger one???
Not so insane if your goal is serious force projection in two or more disconnected theaters simultaneously. The US Navy does a lot more than sink enemy ships. Given that the US is in North American and is on friendly terms with Canada and Mexico, the vast majority of our force projection is facilitated by the Navy.
It's not about relative size, it's about desired capabilities. And if China ever makes a move on Taiwan, I think a lot of people will appreciate the "insanity" of those capabilities, just as they've appreciated our policing the world's oceans for the last 70 years.
< And if China ever makes a move on Taiwan, I think a lot of people will appreciate the "insanity" of those capabilities
How many carrier fleets do you need to protect a small colony? And of course, this is assuming the US would actually go to war with China over Taiwan, which is highly doubtful.
> just as they've appreciated our policing the world's oceans for the last 70 years.
That is highly debatable. Most of the world does not appreciate US imperialism.
> "That is highly debatable. Most of the world does not appreciate US imperialism."
Then I'll happily debate you and say that most of the word does appreciate US peacekeeping and aid. It's easy to throw around the imperialism word without context. What would you call the Belt and Road initiative by China which now practically owns Africa? And who do you think will defend against it when that situation escalates?
I think it's much easier to like Chinese imperialism with things like Belt and Road, which actually helps little people despite all of the downsides, than it is to love American imperialism, which largely consists of coups against democratically elected governments, forced work on US companies' plantations, civilian infrastructure bombing, paying and training terrorists (the taliban, first and foremost), weapon sales to terrorist belligerent regimes (Israel, Saudi Arabia, historically Irak, Iran), forced kidnappings and interrogations, mining the harbors of Nicaragua and ignoring the International Criminal Court penalties for this proven war crime, and so many others.
Of course, it should go without saying that most people would much rather live in the US than China. But to most people who are not citizens, the US is much scarier than China. Exceptions such as Japan, Israel, South Korea, Republic of China (Taiwan), Federal Republic of Germany after WWII are just that - exceptions.
According to Gallup poles, the majority of the world fears the US more than any other country.
Of course America has done harm. But tell me what peace has China kept over the last 7 decades? What little people are actually helped by the Uyghur genocide? By the One-China policy that ignores Taiwan and pressures the other southeastern nations? By the continued oppression of North Korea? By the resource depletion and territorial control in Africa as seen by the Congo power conflict? This is, quite literally, imperialism in action and often gets dangerously close to provoking war.
But sure, some misguided folks might prefer the lifetime dictators of Russia and China much better. I'm sure that'll last until a real conflict starts.
Are you claiming that the USA has been 'keeping peace'? The one country in the world that has been involved in each and every war that has happened in the last 70 years, often on the side of (or being) the aggressor? China,for all of the atrocities they carry out inside their country, has at least not started any wars.
Huge powers are never your friends - that much is certain. Whatever they do is ultimately meant to further the goals of their own citizens (the wealthy and powerful, of course) - this is true of China, the USA, the USSR, and every other empire in history. Some small countries benefit from an empire's influence, when they happen to be in a place where that empire wants stability (for example, Romania has mostly benefitted from US colonization). Other small countries are devastated and thrown into dictatorship (Nicaragua, Cuba, Iran, Honduras, Guatemala, Vietnam, Yemen, Iraq, Afghanistan, Palestine, Syria, to name a few).
Yes, keeping the peace sometimes requires minor conflicts to prevent larger ones, and some regions are unstable at best. Meanwhile China has a population of 1.5B+ on its own and atrocities "inside" are still atrocities large enough to dwarf prior world wars. Same with the existence and suffering of nations like North Korea under their protection.
Your selective dismissal of conflict is telling. If you're afraid of, and dislike, the USA then that's unfortunate, but it doesn't leave much more to discuss.
Except that aircraft carriers are obsolete-- sitting ducks that will be sunk by long range guided missiles within hours of the next Great Power conflict. Submarine carriers with fleets of drones are the obvious replacement.
A true life-or-death Great Power conflict will likely end human civilization, regardless of who wins, due to nuclear weaponry. Why bother trying to win a war that everyone is bound to lose? Until then, submarine carriers are a lot more expensive.
The return is called Pax Americana, a global peace that has lasted a lifetime now. It’s easy to say it’s not worth it when our generations haven’t had to fight through world wars.
Also let's be honest, aircraft carriers are super awesome and fun and good for scaring brown farmers but in a modern war against an equal power they're not especially practical. Couple o' kinetic strikes and your $13 billion new toy is slag on the ocean floor for like, what... cost to get mass to LEO is $2600 per kg so if we want 100 special order deliveries of 1-ton rods from God that's $2.6mil per rod = $260 million to sink a $13 billion aircraft carrier and destroy how many billions of dollars worth of F22s and ammunition?
Like, I love aircraft carriers, they're so cool. But also physics says not so effective. :S
Rods from God are only simple at a high level, but as always the devil is in the details.
1. You have to position the rod satellite in the right orbit, or have enough so one is generally over the target.
2. Then when the order comes in to kill the carrier, your 1-ton rod plus satellite has to de-orbit from ~8km/s. Basically it needs the rocket that launched it, but up in orbit to drop it back down. (It's not quite so bad because gravity is assisting rather than fighting as during launch, but it's still a decent de-orbit vehicle.) The de-orbit takes time, and either you're dropping from ~1000km up or re-entering at some kind of ballistic arc from ~200km up.
3. Obviously the carrier will be maneuvering the moment that massive de-orbit burn is detected. So when course corrections will be necessary throughout the re-entry and maybe even into terminal flight, when your rod is hypersonic in the thickest part of the atmosphere, sheathed in sensor-blinding, comms-blackouting plasma.
(I'm assuming a CIWS—point defense gatling—throwing up a cloud of metal wouldn't do much to the rod, nor would an IR missile be able to hit the rod, but maybe those things could alter its trajectory enough to cause a miss.)
4. Then if you actually hit the target, did you over-penetrate it, smashing a 1m hole clean through the hull into the water, or did the rod explode like a bomb against the hull? (I assume the former but am very unsure here.) If it's just an unstoppable but small hole, damage repair teams would patch it and seal off those compartments to keep the ship fighting.
So in the end, you have a very expensive (let's use your $260M), unmaintainable hypersonic slug that everyone can see launch (and who launched it) and it might be able to poke some holes in a carrier.
Or you use normal hypersonic missiles, which should be harder to detect launching, more maneuverable, and might deliver explosive or nuclear payloads.
Or you launch a swarm of hundreds of relatively cheap anti-ship missiles and just overwhelm the carrier defenses that way.
So I agree the dominance of the carrier will last only as long as the next great powers war (and also that guided missile submarines might well be the future) but it's from fear of God raining down tungsten wrath.
Honestly the most important use of a carrier (especially for china) is going to be in supporting naval vessels interdicting against pirates harassing or stealing from oil tankers shipping from the middle east; china depends on mideast oil to feed its people. The us does not as of 2019-ish, and may in the short to mid term cease protecting international sea lanes especially in the mideast since we are rapidly disengaging out interests in the area (e.g. pulling out of Afghanistan).
Of course they can be mitigated. Knock out the targeting or launching platforms and you break the kill chain. Plus hypersonic cruise missiles and railguns are still mostly in the research phase, and it's looking like railguns might not really be workable at all.
1. Sure once we're under way but that doesn't change how good they are from a first strike perspective.
2. As a species we can land a rocket on a barge, do you think we can't land a big crowbar on a slowly moving target?
3. Might make 2 more difficult but a 1-ton tungsten rod is pretty durable.
Certainly more potent against a static target but with modern tech and one skilled, ethically ambivalent engineer, these days you could probably hit a row boat.
Because the barge is carefully positioned to be in a place this exact rocket drops from the sky.
Satellites are not 'sitting in orbit', they are falling on earth extremely fast, and not reaching it only because they fall sideways. Since they go very fast, they have immense momentum. To attack a target you have to steer that momentum elsewhere, and that takes a lot of energy and precision,and you also have a very small attack area for every satellite. So to cover all earth reliably you'll need a constellation with numbers like Musk's Starlink - i.e. thousands of satellites.
Do you really not understand the differences in difficulty between a cooperative, planned ahead rocket landing, and an adversarial attack on an actively evading target whose position may not be precisely known even at the start of the attack?
Due to limits imposed by basic physics there's no way to build a really stealthy satellite. The power source, whether solar or nuclear, necessarily generates a large radar and/or IR signature that can't possibly be hidden from military grade ground sensors.
What equal power? Even if you have the launch and weapons capability, kinetic bombardment from space is not effective against a moving vessel. Aircraft carriers are faster than you think. They're also incredibly important in air superiority, and controlling the air is what wins wars.
Assuming you can successfully attack one, you still have plenty of cruisers, assault ships, support craft, secondary/light carriers, subs, and several other carrier groups now headed straight for you. It's not like countries can't make a crazy plan to take out a single carrier right now, it's what would happen after that is the deterrent.
A paper I read recently (Harper 2016 - 10.1089/space.2015.0029) has numbers based on the supplies needed to the ISS.
The gist was, "Without some sort of recycling and/or use of in situ resources, meeting the lunar settlement goal of 100 people would require delivery of over 1 million kilograms of life-support consumables per year."
And then assuming a PLSS life support system you get to to needing about 5500kg of consumables delivered per person per year.
So ~5T/person/year, let's plug in the Starship launch costs: at $1mn/T, this is only $500mn/year for the whole base. This seems a little too good to be true.
Isn't this pretty much the point of such an endeavor though, or at least part of one?
There's a lot of science we'd like to do on the moon, chief of which would be to actually test the space-settlement self-sufficiency problems in an environment like that.
With the ISS as comparison, it's not going to be "bam 100 people" it's pretty obviously going to be a process of rotating in progressively larger crews while the systems and bottlenecks are worked out. Not to mention we'll benefit a lot from the sort of focused sustainability research this will generate.
there are experiments with moon simulant and mars simulant. both show that with proper prep, regolith is a sufficient grow medium. just as is, it sucks, but if you wash, and then fertilize, it will work. and then after the initial prep, you treat it like you would other soil.
there are a few really good proposals for lunar economy.
pulling glass for zblan fiber works better in micro g than here on earth. many theorize that low g on moon would also result in a higher quality product than we can make here in earth, and this quality of fiber is very expensive currently up to 1000+ epr meter, if it becomes trivial to make it on the moon, the moon very well could provide all of the manufacturing for the fiber optics here on earth.
there is the helium3 mining argument. although I'm not sure of demand.
it is cheaper to supply LEO from the moon than it is from earth. mining water, growing food, manufacturing rocket fuel, are all possible on the moon, and are a product for Leo space stations. nasa alone payss >6bil a year to resupply the ISS, that's not including Russia, esa, jaxa, etc. not all of these resupplies can be replaced by the moon, but a large portion of them do contain food, and basic products that theoretically could be manufactured on the moon.
mining various minerals on the moon like aluminum may be more expensive, especially at first. but how do you quantify the habitat destruction? regulations may force earth mining into oblivion and make moon a reasonable alternative. not likely to happen, but maybe it should.
as you stated tourism probably will be popular IF you can make it affordable to the middle class.
low g research as a service is also a good revenue model. many people pay good money to have their experiments performed in micro g, it's very reasonable to assume the same will be true for lunar g.
also, all moon/mars bases put a HEAAAAVY emphasis on Insitu resource utilization. early moon bases will be expensive and very likely a net loss. but almost every single plan I see around basically says "step 1. get there. step 2. achieve self sufficiency asap except for complex manufactured goods"
things like water, food, air, fuel, building materials, bio plastics, paper products, basic manufacturing/cnc/printing of tools and replacement parts. most thing short of chip production panel production and super complex manufactured goods are very achievable, and will theoretically mean that 10 years after moon base alpha, very few resupplies are needed
Yeah, but one of the big parts of the Brexit referendum’s two Leave campaigns was moping about a number merely twice that size being spent for all the combined benefits of a customs union and single market (the absence of which is now being blamed as a partial cause for empty supermarket shelves!), not something which cynics already deride as a billionaire size-measuring contest. Much as I love space, any proper space program — even ones well short of colonies — must do something tangible down on Earth.
I'd be careful taking anything from the brexit campaigns as evidence of anything. It was a baseless conclusion in search of excuses...
I take the wider point though. Its hard enough to get voters to find money for anything other than pensions, tax cuts or bombs.
People love criticizing Bezos and Musk for spending money on rockers. But I actually think they're fulfilling something we as a society have sadly neglected.
Will we ever get to some other metric than "money" WRT 'returns'?
I've always wondered about this WRT "black budgets" and the theories about Breakaway Civilizations; "Of what value does 'Money' have in Space?"
---
Lets assume that trillions are funnelled off into black budgets for [purposes] -- that assumes that hte 'money' (fiat currency (paper/the-concept-of-value/10101010s/etc)) is being used to pay for/buy [goods/services] -- Where the hell is all this money going? is there an economy and a place where such vast amounts are being spent.
Lets assume they are paying their engineers/suppliers/companies/etc - the Deep Workers far beyond the depths of SkunkWorks etc - where exactly is that money going? What are they buying.
This has been the biggest flaw for me in thinking about Breakaway Civs - and spending money/making money in Space.
If we were to assume that the moon had some set of valuable minerals/etc that would be beneficial to mine and then return to earth, where is the value in mining Tungsten on the Moon (given your shipping calc, for example) and bringing that back to earth unless the earth had none of said resource...
Personally, it would be interesting to think about how a production capability could be built on the moon to support the fabrication and manufacture of vessels on a lunar-orbitting ship-dock, which then could carry on to mars/wherever... and pull from the resources of metals on the moon, which AFAIK is supposed to have a lot of metal...
Further, why has Musk constantly talked about "going to Mars", but said seemingly very little about doing a dry-run, proto, etc to the Moon first?
Shouldnt building a Moon-base be much more immediately important than a Bezos-esque trip to Mars?
FFS SpaceX is talking about getting to Mars, but all the required life support eco-system requirements do not appear to have been even addressed?
Re: Musk and Mars - because that's his founding reason for SpaceX. His original idea was just "I have a lot of money, what's something absurd I can do?" and the answer was he wanted to land a greenhouse on Mars - then got jerked around trying to buy Russian rockets to do it and then realized he could just make his own rocket company.
Elon is slightly crazy as most billionaires are, he's just crazy in a very specific direction: some people buy mega yachts, he wants a SpaceX rocket to be landing humans on Mars.
Now in reality...SpaceX can't privately fund a manned mission anywhere. That's got to be a NASA/international thing - if only because the core competencies are so incredibly broad-ranging (SpaceX do rockets - and rockets are already a "here's 50 fields you can contribute a Ph.D to, we need all of them to make this work"). But if your goal is to go to Mars, then you talk about, and build towards, going to Mars and wait for NASA to say "hey we'd like to get the moonbase going".
Which is pretty much what has happened: I have no doubt that in the next 20 years we're going to see a manned mission to the Moon, and I'm very sure that it's going to be a Starship that takes it there.
I seriously doubt it. While China's made a lot of progress, there's no possible way the US government isn't suddenly going to discover a priority if there's a risk China gets another man on the moon first this century.
Wouldn't nitrogen and carbon just be kind of a one-time cost of any new expansion? Once they're there in a closed loop, you shouldn't need to constantly ship more.
I'm also curious about your assumption that any station on the moon needs to be run for profit from extractive activities or tourism. McMurdo uses a lot of supplies because it can. Its design is not as
self-sustaining or fault tolerant as a moon base would have to be. A slightly better analogy would be Amundsen Station.
Honestly I think the sanest model is one of progressively building a surplus atmosphere for reserves and to fill new modules. Ship food up, astronauts convert it to carbon dioxide and urea, and whatever of the latter you can’t convert back to proteins ends up as free nitrogen, which you can use to build air.
> It's not easy to imagine a lunar base generating >$7bn of returns every year. Apart from space tourism, there isn't a whole lot you can do/build/sell on a moon base that has more value on Earth than it would cost to transport back here.
Perhaps manufacturing? We might find out stuff that is better done in low gravity.
> Assuming Moon Base runs on a similar scale, that's an initial annual budget of $7bn just for the shipping.
Wow that seems like a lot, which figures for launch and payload delivery are you using? Because NASA was like $1mil per kg to LEO and isn't SpaceX like $5000?
Get back to me on 3He fuel mining in the regolith after (a) demonstrating a working 3He cycle aneutronic fusion reactor (hint: it's much harder than the D-T fusion cycle that we haven't got working yet, although ITER is supposed to demonstrate it), and (b) ruling out other aneutronic fusion fuels like, oh, proton-Lithium-7, or proton-Boron-11 ... which are only somewhat harder to achieve than 3He fusion, and which run on fuels readily available here on Earth.
(My gut sense is that if aneutronic fusion is practical at all then it'll be cheaper to build more expensive reactors that can run on terrestrial fuels so cheap we use them for car batteries and as an insecticide, rather than slightly less difficult reactors that are fuelled by magic extraterrestrial unicorn sparkle-dust.)
I saw a blog calculate that regolith He3 was so sparse that even with a reactor to use it in, one would make more energy from purifying the metals, coil-gunning the purified ingots just past the L1 point so they would fall to Earth, and setting fire to the ingots. Or, entirely separately, by pointing the ingots at electromagnets and collecting the energy from the induced currents from electromagnetic braking.
(I wish I could find the original and link to it. For all I remember it might have been you who wrote it).
Helium-3 from the moon will never be a commercially viable energy source. At best it might be captured incidentally as part of other mining operations and sold to research labs. There are just too many other fusion options that, while not as ideal, have fuels that are vastly easier to obtain.
It is likely that permanent low gravity will kill them even before boredom and depression from realization that the rest of their lives will have to be spent in those small confines.
(Low gravity is extremely unhealthy. And even a relatively short 1-week stay in such conditions severely affects cardio muscles, so that super-healthy astronauts have to exercise for several hours per day to keep their heart in shape)
One has to wonder if you couldn't eventually just build a large centrifuge on the Moon. Put a toroid on some kind of magnetic bearing and rotate it. It should be easier than on Earth anyway since you're supporting only one sixth of the weight of the structure. Even just as sleeping/recreational facilities, it still might be worth it in the long run.
Fusion power plants already seem unlikely to be economically viable, given the huge radiation damage that the whole structure takes, requiring constant disposal of radioactive concrete (presumably via robots) and rebuilding the structure every 10 or so years. Adding lunar-mined fuel to the process seems to be going in the wrong direction.
I assume that catering to those 70 Uber wealthy might increase cargo needs slightly. But it would cut down on family visits. The kids might pay to have grandpa sent to the moon.
It looks like you are using a price of $1000 / kg to get that figure. Prices will be much lower than that once fully reusable rockets are widely deployed.
Currently, equipment costing tens of millions $USD are thrown away on every launch. It’s hard to overstate the shift fully reusable rockets will bring.
People were optimistic about LEO shipping costs when the Space Shuttle program just started, but it didn’t exactly work out economically. Partially reusable F9 was meant to decrease lunch costs, and it did, but not to the extent some hoped. Starship, no doubt, will bring prices down, but then again, even $1k/kilo to the moon surface sounds kind of… an aspirational stretch.
Ah, my bad. I somehow got mixed up and thought we were talking about LEO prices. I agree, going below $1K/kg to the Moon's surface may be hard even for Starship as it looks like it requries multiple tanker Starship launches to refuel the payload Starship waiting in orbit. I do think LEO prices will probably be lower than $1K/kg.
I believe Falcon 9 could be priced a good amount lower and still be profitable on a per unit basis (ignoring ongoing R&D) but SpaceX has little pressure to do so as there isn't a competitor with a similar offering. It's interesting, as once Starship is out it may somewhat cannibalize the Falcon 9 marketshare.
You raise a good point about the shuttle, however SpaceX can learn from that. I'd bet they are striving hard to make Starship more effectively and efficiently reusable than the Space Shuttle was. We shall see how successful they are with that. I'd be very surprised if it was not a significant improvement over the reusability of the shuttle.
Perhaps the real paradigm shift will occur once there are two or more companies with fully reusable rockets such that there is more competitive pressure to cut margins and lower prices.
I’m pretty sure Starship is going to be more economically viable than Space Shuttle ever was, I didn’t mean to compare them directly. And you’re right, $1k/kg to LEO doesn’t sound unattainable even for F9.
With the ride-sharing Starship is totally going to cannibalize Falcon rockets, but I thought that was the point all along? I wouldn’t be so quick to retire F9 though. Even if Starship adoption is smooth, it’ll take years to certify it for crewed flights. And there’s always market for smaller launch systems (Electron seems to be doing well).
The Space shuttle program was run by people who were in the taxpayer wealth extraction business. As we've seen already, no one really imagined how we could progress on costs when companies actually get into space transportation business
You’re totally right, Saturn V, Space Shuttle, SLS – all of them are great technology, but financially speaking, they were all doomed from the get go. I weren’t trying to compare NASA and Space X, I was trying to point out that optimistic outlooks on large reusable rockets usually don’t fully consider implications of increased complexity of such project.
SpaceX money is also made the same way. It's US gov money that funded much of the research anyway, US launch facilities that handle the launches, and SpaceX is charging the US government many times more per launch than it charges for commercial launches (they claim the government has extra requirements) .
Personally, I think the most viable long term option would be to build solar farms with 120 degrees separation on the moon's circumference so you'd always have a fairly constant amount of solar power generation & run a HVDC grid. From what I can make out, a 1000 Amps capable Aluminum Composite core power cable seems to weigh about 500kg per km [1](I may be mistaken here, happy to be corrected). Moon's circumference is about 10000 km & so you'd need about 7000km of cabling or about 3500 tons. That's only about 20-40 Starship trips to transport the cables itself. Maybe with some minimal cladding (no rain/ice etc on moon), it could possibly even be laid or
buried on the ground vs. requiring pylons. Once the solar panels are installed, there's little maintenance needed compared to earth (dust) and you could progressively add over time.
If you solved constant uninterruptible power though via solar, then you've solved a lot of other expansion problems.
So your real challenge is what can be done if you just lay cable over the surface - then you use that power source (and importantly: heating source - lunar night is why rover missions struggle to last over 2 weeks) to power your second-wave rovers which would lay in higher amperage stuff (which would basically just need to in contact with regolith while shielded from sunlight to be cooled).
Well, if you can manufacture high power aluminum cables on the moon, it would be worth some extra pain setting it up. Assuming any real plans for permanent settlement.
I find it odd that the author dismisses hydrogen storage largely based on the requirement to mine water for electrolysis and then goes on to propose using ~12,000 tonnes of water for thermal energy storage.
Well it requires a closed container that maybe has to take a few psi of water pressure. It doesn't require anything that can tolerate thousands of psi like hydrogen does.
That's a brilliant idea. You could store the hydrogen in some big balloons. There's no buoyancy on the Moon, so you don't need to anchor these balloons. You need to cover them with a dome to protect them from micrometeorites, but when you establish a Moon colony, building domes is the name of the game. At normal (on Earth) room temperature and pressure, a balloon with a radius of 10m holds about 60 kg of hydrogen. I did some back of the envelope calculations, and that would be enough to provide about 2 kW of power for the length of the lunar night (14 days).
It's funny, I never thought of electricity as being a big issue for a moonbase. There are so many ways to store potential energy - you could, for example, put a bunch of moon rock/dust on a platform and run electric motors to raise it for 14 days, and then, during the lunar night, allow the platform to lower and generate electricity. But the remarkable 300 deg temp swing is a dream for power generation, although the OP is right that you'd need a medium (e.g. lots of water) to harness it as a carnot engine. Still, fun to think about since it's a hard, but not unsolvable problem.
How about two/three sites around the Shackleton crater which beam power back and forth wirelessly across the crater as each site goes in and out of sunlight?
From a linked research article on the main site, they had a compelling plan bounce energy around with mirrors so you don't have reconversion losses. Tracking mirrors and solar panels. The light from the sun is highly collimated.
Interesting, but surely the last thing you want is complex mechanical systems involved that will quickly wear out due to lunar regolith, or having to transport large mirrors to the moon?
Sure you get losses from wireless transmission, but you can always just add more solar panels, as they're cheap, lightweight and compact.
You only need a small amount of power to keep things going during the 14 days of darkness, so you can avoid transfer losses by doing the intensive stuff during the 14 days in the sun.
> Light Bender is a novel concept for the generation and distribution of power on the lunar surface within the context of the Artemis mission and the “Long-Term Human Lunar Surface Presence” that will follow. The innovative concept is based on a heliostat that utilizes Cassegrain telescope optics as the primary means to capture, concentrate and focus the sun's light. A second key innovation is the use of a Fresnel lens to collimate this light for distribution to multiple end users at distances of a kilometer or more away without substantial losses. The redirected and concentrated solar energy is then converted to electricity at the end user’s location using small (2m-4m diameter) photovoltaic arrays that can be mounted on habitats, cryo-coolers, or mobile assets such as rovers or ISRU elements. This concept is superior to alternatives such as highly inefficient Laser Power Beaming, as it only converts light to electricity once, and to traditional power distribution architectures that rely on mass intensive cables.
... or even better, infrared telescope. (Both, really, at once.) With the mirrors separated from the focus by miles, they could be simple optically flat surfaces, as many as you like; and so far apart, the resolution would be unmatchable. It would probably be most useful for deep-field imaging, because to can't point it; you rely on it happening to point at something interesting, which likely means stars in galaxies very far away.
The idea I have always liked, though have never done the numbers on, is a giant “heat pipe” that would circle the moon. You could put it on any latitude you want, but you effectively take advantage of the temperature gradient to continuously flow a gas/liquid around the moon. That in turn turns turbines attached wherever you need the power.
the only answer is nuclear, simply because of energy density required for space applications.
the creators of the original solid-core Krusty/Kilopower reactor are trying to commercialize the tech, I hope they have enough funding (@sama, I hope this is on your radar) https://www.spacenukes.com/
“The answer is nuclear” is repeated often but often is an innumerate answer. Kilopower for most uses in the inner solar system performs considerably worse than solar. The power to weight ratio of Kilopower is about 6-7W/kg, no better than old time RTGs. UltraFlex solar panels do about 150W/kg near 1AU.
Nuclear in the lunar case may be useful for base power due to the long lunar night which makes storage pretty heavy, but nuclear is actually usually WORSE performance than solar, producing much less power for the same mass. It’s only in the outer solar system around Jupiter or in niche cases like lunar night where nuclear has a solid lead on solar. Otherwise it’s similar or worse, besides being a lot more expensive. ~$100 million for 10kWe Kilopower.
i think you are missing the point of Kilopower, it was to build a working micro reactor prototype on realistic timeframe and actually ship it, they have designed the extension of this to MW scale where energy density is order of magnitude better.
Nuclear scales better than any other source of energy. How many sq feet of solar panels do you need for 1, 10, 100, 1000, 10000 MWe, now translate it to lbs and $$$ cost (including shipping to the moon or mars base), also consider dust and lunar night conditions affecting solar use.
if you look at scaling it vs. weight and cost (including maintenance and replacement panels over 20-30 years), solar is no competitor to nuclear.
No, the larger nuclear power plants (50kWe) NASA has developed to reasonable TRL are still around the same power to weight ratio. Nuclear, in addition to everything else like the dynamo and the reactor itself, requires heavy radiators.
Also, Kilopower has a SHORTER lifespan of about 15 years whereas solar can last 30-50 years (solar degradation is much slower than is often claimed, at least when we’ll engineered and in the absence of high humidity) as there’s no moving parts and nothing to refuel. Remember, terrestrial nuclear reactors are regularly refueled (annually?) and maintained.
The traditional argument has always been that nuclear scales better than solar, but usually such comparisons are looking at sandbagged, outdated solar panels and very low-TRL nuclear designs relying on super high rejection temperatures (ie unrealistic) or shorter lifespans.
I’m not anti-nuclear by any stretch, and I fully support increased funding and deployment of nuclear power, but I think there has been a lot of hand waving by some nuclear advocates. If you look at actually achievable, near term nuclear designs, none of them perform anywhere near as good as solar does in orbit near 1AU, and it’s not even close. It’s surface applications or outer solar system where nuclear has a chance against solar. Outside of those cases, solar is much more powerful for a given weight (meaning cheaper to transport) plus being far cheaper to build and not requiring special launch vehicle risk mitigations (currently, the only nuclear-rated launch vehicle is Atlas V… and every nuclear launch must be approved by the executive branch).
(A human Mars base may benefit from a mix of power sources for resiliency purposes.)
No. The lunar night is 14 days long, which means you need 336 kWh of storage for every kilowatt of constant power. In orbit, you only need maybe 30 minutes of battery, so 0.5-1kWh per kilowatt of power. Mars surface has a similar day/night cycle as Earth, plus a need for margin for dust storms, so nuclear is roughly the same mass as solar if you need near constant power, but still solar is potentially cheaper if you need a LOT of power.
That’s pretty reasonable. Particularly since nuclear (fission or radioisotope) produces a lot more heat than electricity (thermal to electrical conversion efficiency is just 23% for Kilopower and 3-9% for RTGs), so using it for base heating during the night is a much better argument. And even some solar powered rovers like Spirit and Opportunity used small radioisotope heat sources to stay warm.
On the moon, Nuclear has basically the opposite problem of solar: Long, hot days mean that nuclear power generation is hard to cool during the lunar day.
This means that nuclear for the moon is basically directly competing with batteries and other storage solutions in terms of weight/risk/difficulty.
>Unfortunately, it turns out that the minimum altitude necessary to avoid any shading is 2750 m, rather taller than any structure ever built on Earth.
Well, you wouldn't be building it on earth. The gravity on the moon is 1/6 as strong, which I understand means it could be 6x as tall as anything on earth. Granted, this would still be massive, but closer to reasonable.
>there are numerous places on the surface of the Moon, including close to polar regions, that are always in view of Earth.
As I recall, the moon is tidally locked - half of it is always visible to the earth, the other half never is. Is he just qualifying that the poles are the exception?
>Microwave antennas positioned here could receive power beamed up from the surface of the Earth from one of at least three stations such that one is always in view.
Why based on earth? This means you have to deal with earth's atmosphere, which creates other problems. My suggestion would be to put satelites at the moon-earth lagrange points, and have them beam power around. Knowing nothing about the analysis of these things, this would probably lead to a simpler array. You could also probably eliminate the proliferation concern this way, eg by putting it at the L2 point.
ALICE is a rocket propellant made of aluminum and water. Both are available on the surface of the moon. Just make it using solar panels where the sun shines, and ferry it around using lunar rovers. If it can be used to propel rockets, it can be used to power turbines for electrical generators.
And if people don't like old-fashined turbine-based dynamos, then, why not go for Alcoa's aluminum-based battery [2] ? The lunar regolith (dirt) contains plenty of oxygen and aluminum [3].
This may be feasible as a long term solution, but how do you bootstrap the energy-intensive process of extracting and purifying aluminum in the first place?
You can bring let's say 100 tons of aluminum from Earth. At an energy density of 1.3 MWh/ton [1], you'd have 130 MWh of storage. And since there are 336 hours in the lunar night of 14 days, that corresponds to a power capacity of about 0.4 MW, which should be fairly decent for the bootstrap period.
I’d imagine they’ll need to do a number of electrochemical reactions to make oxygen to breathe and fuel to burn, etc... Use an oversized solar array and store the chemical products in tanks. Batteries are chemical stores too, no? Anyhow, not sure of the efficiency of all these reactions, but more panels could help until further reaction improvements can be made.
The article does consider that option via splitting and storage of water, and then recombination via hydrogen fuel cells.
According to the article the mass of the storage vessels needed to store 2 weeks of pressurized hydrogen and oxygen are comparable with the mass of batteries you'd need, although I haven't done the calculations myself... Intuitively I would expect this to be more efficient than batteries though.
I think the point here is rather that power load at night can be much lower than power load during the day, if most of the energy is going to optional processes like making oxygen and/or rocket fuel.
Yeah. Nuclear may not make sense here on Earth -- even Antarctica -- where the environmental and human health consequences are practically unavoidable (especially when implemented by the lowest bidder), but space outside of LEO is another matter. NASA is in fact looking at it. https://cen.acs.org/energy/nuclear-power/NASA-thinks-nuclear.... Although the idea of migrating researchers to a sunlit base when night falls at their primary base has potential, it's probably going to be more practical to stand up a whopping big RTG or full-on fission reactor a distance off from the habitats. Space borne fission plants are going to be necessary anyway if we're ever going to send people to the outer solar system (Jupiter, Saturn, Uranus, Neptune). We might as well learn how to make them work on the Moon ("It's a damned research project!").
A smallish chunk of Strontium-90 would safely power quite a lot of moonbase for years, as the Soviets did their remote lighthouses. Strontium-90 is the ideal radionucleide; emitting negligible gamma rays or neutrons, it just sits producing heat.
For power in the cloudtops of Venus, Titan, Saturn, Uranus, or Neptune, a full-scale nuclear reactor is as simple as a naked atomic pile hanging near the bottom of a big fabric tube with a wind turbine at the top, supported by a balloon. All the radiative output goes into heating the air around the pile, which rises and drives the wind turbine, which is the only moving part.
On the gas giants, it would have to be supported by a hot-air balloon, because the atmosphere is hydrogen.
On all four planets, surprisingly, gravity is very close to Earth-normal. (On Titan it is rather less.) Orbital velocity at the gas giants is much higher, though, so as comfortable as it might be there, it's hard to get home from them.
The tricky part about nuclear in space is that you either manufacture the fuel somewhere off Earth too, or you need to launch it from Earth, with a non-zero chance of the rocket failing and tons of highly radioactive fuel contaminating the atmosphere.
I would probably risk that on a rocket that proved to be reliable enough, say, 500 launches in a row without a single failure.
In practice you wouldn’t send a giant amount of fissile material in one shipment from the earth’s surface, you would put small amounts up at a time. Multiple trips to the moon would be needed anyway.
That reduces the maximal extent of the problem if something goes amiss, but increases the total risk of at least one launch going amiss.
In practice, if something like that happened, environmental organizations would lobby hard to put a permanent stop on launching radioactive fuel from Earth, regardless of the actual extent of the contamination.
It’s both hilarious and sad that we don’t talk about nuclear because other countries will think we’re building bombs. I definitely think the space treaty has to go and be replaced by a reasonable treaty that allows militarization of space.
Right now it’s akin to nobody building planes that can Cary more than a single person (and no cargo) because they know it gives the other party an advantage
You're creating an imaginary strawman and arguing against it here.
The space treaty does not ban nuclear power, only nuclear weapons. Nuclear power is just for the most part not worth it, and in the rare cases where it has been worth it, we've used it, in the form of RTGs because that's the only form of nuclear that has ever made sense for any space mission we've launched. Nuclear power is talked about a ton in the space community, with everything from "here's a way we could potentially power spacecraft to bases" to "hey, maybe we could build a nuclear powered rocket engine and get much better mass ratios when we send things to mars".
I said that because nuclear weapons are restricted when anyone wants to build anything nuclear in space it gets put on the back burner because no one wants to piss of other countries (who are understandably afraid of it being a covert weapon.)
I didn’t create a strawman, you did by claiming I did and then arguing against that. You did by claiming it’s talked about in the “space community,” whatever that means, when we’re talking about actual space infrastructure in the implementation phase.
It is simply not the case that nuclear weapons being restricted means anything nuclear in space gets put onto back burner. And there is no serious opposition from the poliferation from despite your strawman that there is and your strawman that it is forbidden by the outer space treaty. This is not a strawman on my part, I am directly addressing the argument you actually made in your comment, even if I was wrong it would not be a strongman, and I resent the fact that you would say "no you" when it is obviously false.
Space community here is just a throwaway phrase I used for the various entities involved in Space, space agencies like nasa and the esa, research agencies like darpa, and the huge groups of contractors around them. For instance the latest award of funding that I'm aware of from the US is that General Atomics was awarded $22 million in April of this year for nuclear thermal propulsion research (and theoretically to demonstrate it on orbit by 2025, I'm fairly skeptical that they will meet that goal): https://www.ga.com/general-atomics-awarded-darpa-contract-to...
>I definitely think the space treaty has to go and be replaced by a reasonable treaty that allows militarization of space.
It's hilarious how you and MichaelZuo (and every one of the idiots who denounced the US Space Force before its creation) don't actually know what the Outer Space Treaty says.
The treaty does not ban "militarization of space". As gpm said, it only bans weapons of mass destruction in space. Space has been heavily miltarized for 60 years; for the entirety of the space age, military and intelligence agencies have been far, far larger users of space than civilians.
Yes. We are only putting it off at the moment and it’s hampering progress. If we could put nukes in space it would remove the stigma of using nuclear energy. And other countries could build their defenses so they aren’t as worried. We should build a more realistic treaty that doesn’t hamper progress.
Well I mean you do live up to your username but you surely understand that there could be second and higher order effects of such a change in policy and geopolitics? And that these effects could be so great as to overwhelm whatever merits and demerits the first order effects obtain?
Although positive and productive effects may accrue it seems highly unlikely when all things are considered that they would outweigh the negative effects and externalities.
Sadly the moon's gravity is 1/6th of the earth's, so each block would have to be six times the mass, or you would have to lift it six times as high to store the same amount of energy.
What do you need for basic human life support? Light, oxygen generation/CO2 removal, water, and electricity for vehicles and work appliances.
Oxygen and water can be stored in tanks sufficient enough to ride out the 14 days dark cycle, LED lighting is extremely efficient (especially if everything is under 9m of moon soil, so no light can escape useless to space), the only thing that may be a problem is CO2 removal - no idea how much energy that uses.
I think CO2 depends heavily on what you're doing with it.
You filter CO2 out of the atmopshere using zeolite beds at relatively low temperature/high pressure, you then recharge those by venting the beds at relatively high temperature/low pressure.
If you're venting the CO2 to space (they do on the ISS), I don't have numbers/proof to back this up but you probably don't need much energy at all. You just pass air through the absorbing bed at ~1ATM (i.e. with a fan), and a heat exchanger from the venting bed to the absorbing bed might even be enough to keep the temperatures in the right range.
If you're capturing the CO2 afterwards however, you probably need some more energy-expensive machinery. Again, I don't have numbers, but you're definitely talking about running a compressor to force the venting CO2 into a tank now, and you might want to compress the absorption side as well to get a bigger pressure gradient.
The only real use of that captured CO2 is to recycle it into something useful (e.g. O2 and CH4 using the sabatier reaction), and that reaction is going to be endothermic, but you can probably just store the CO2 until you have sunlight and do it then.
Agreed, it would be quite an operational hazard and probably an unethical experiment to leave astronauts on the moon for long periods. Factoring in appropriate safety margins for equipment, supplies, physiology and rescue flights, they could only stay there a few months at a time in any case.
I'm not trained in STEM at all but these discussions are always a little confusing for me because if our goal is to bootstrap mining/manufacturing in space, why does everyone jump to expensive, complicated and inefficient solutions like "energy lasers" when we've had power lines for like 150 years and can make them on-site much more easily?
Its likely because bringing a smelter and wire drawing machine don’t feel “space age”. Also most people think of small bases where its not cost effective to bring a bunch of manufacturing capacity as quite a few processes don’t scale down well. Mining is another issue as you would need to find good sources of each major metal within transportable distance of your base.
With the current capital cost of ~$50/W to beam power, its reasonable to think about for small endeavors, but for a base designed for 100k people making power lines onsite is better, as you will need that manufacturing capacity for other things anyway.
The article mentioned why very quickly while discussing building multiple solar farms so that at least some aren't in shadow at the same time: sending enough cable up on rockets to connect all of them would be more expensive than the "expensive, complicated and inefficient solutions".
Well, cables are going to be cheaper at some distance and power beaming will be cheaper at a greater distance, and the question is, where's the crossover.
Look at the efficiency numbers on contact free charging pads. "Beaming" fails for power transmission immediately; it needs other factors to justify the efficiency hit; and once you're out of near field its much much worse.
Solar panels are quite useful, and they are essentially just beamed power receivers. And if you focus the beam instead of just using a glowing ball of hydrogen, go with a more efficient wavelength and remove all the atmospheric losses, it actually becomes quite efficient.
> Solar panels are quite useful, and they are essentially just beamed power receivers
Yes, but they are because their power source is unbelievably large and free. If you look at their efficiency from the perspective of what the sun puts out, they're laughable.
Problem is, with the moon beams we don't have infinite and free source power to waste on inefficiency.
> And if you focus the beam instead of just using a glowing ball of hydrogen, go with a more efficient wavelength and remove all the atmospheric losses, it actually becomes quite efficient.
Focusing the beam is not that easy, you need to hit a moving spot of minimal size with an extremely powerful laser. Avoiding all atmospheric losses is probably not going to work, either. Lastly, you need to get those transmitters built on earth, which, as the OP points out, quite land intensive.
It is a theoretical option, but I would not call it efficient.
> Yes, but they are because their power source is unbelievably large and free
Power sources on earth are also plentiful and almost free, compared to building stuff on the moon (at least until we have a lot more infrastructure up there)
Its probably more realistic to put a few satellites in orbit of the moon and beam power from them. This keeps the distances down so the transmitter and receivers can be more reasonably sized.
If you also switch to laser power beaming, they can illuminate the existing solar farm so a separate receiver is not needed.
Wouldn't you just use earthlight and normal solar panels? The internet says moonlight is 1/345th the power of sunlight but once you factor in Earth's larger radius and larger albedo you get 1/9th the power of sunlight. IE you just use 10 times as many solar panels to get you through the night.
Even if you are off by orders of magnitude, there may still be a useful thought in here.
Find a large symmetrical crater pointing directly at Earth. Silver its surface with very cheap to transport BoPET (Mylar). Once installed, there's no need to worry about the sheets flying off or dust blowing over since there is no wind. Place a solar / thermal collector at the crater's focal point. Reap power from earth-light.
If you choose a large crater, an MVP system can go live with just a small collector and small portion of the crater silvered. It can subsequently scale as your growing operations demand more power.
It can do double-duty in broadcast communications too.
We don't need the heat for fire. Maybe for comfort though. The moon gets mighty cold at night. Its temperature range is about 80 to 370 Kelvin.
You could use the same kit to radiate away some of that intense daytime heat too. Spread it across all of Earth.
Now as to solar PV, in principle it might be doable I guess. But I am not able to make the necessary calculations. How large would the crater need to be for 10MW say?
Even as a heat engine, you might get useful power out. If you could achieve say 150 - 200 celsius difference between your concentrator and night time temperature of the surrounding rocks. Which rocks serve as both the engine's heat-sink and a relatively comfy foundation for your habitat.
> The internet says moonlight is 1/345th the power of sunlight but once you factor in Earth's larger radius and larger albedo you get 1/9th the power of sunlight.
That sounds weird. As per Wikipedia, Sun's apparent magnitude is around -26.7, full Moon's is -12.7, so the Sun is 400000 times brighter than the Moon under the best circumstances. Earth being larger can't correct this by three orders of magnitude.
> Achieving a beam that narrow (1/2000000 rad) from the Earth would require a phased array spaced out over a much larger area, at least 200 km at 5 Ghz (6cm).
I doubt they'd want a very large band but in microwave work I dunno what counts as "large".
and i'm a little afraid to go look deeper into this because i'll wind up tearing up junkyard microwave ovens and building something i shouldn't.
The headlight vs. sun comparison (which I think was an edit?) is irrelevant because we're comparing the amount of energy deliverable over distance. The energy delivered by the sun (at a tenable band) vs. the energy delivered by the remote transmitter on earth, after the 'link budget' has been applied (taking into account distance, atmospheric attenuation, and so on) are the two things that need to be compared.
solar constant: 1.36 kW / m^2
earth-to-moon range: 400 km
parameters from the article:
frequency: 5 GHz -> wavelength: 6cm
earth antenna array linear dimension: 200 km
transmit power density: 100 W/m^2
Let's assume that the earth antenna array elements are 50m wide, and spaced out such that they cover 1% of the total 200km * 50m area, for a total antenna aperture of 1e5 square meters (10% of the SKA).
Combining the stated transmit power density of 100 W/m^2 with the antenna area, we get a total transmit power of 10 MW.
Throw it at Friis:
power density at moon = transmit power * earth antenna area / (range^2 * wavelength^2)
= 10e6 watts * 1e5 m^2 / ( 400e3^2 m^2 * 0.06^2 m^2)
= 1.73 kW / m^2
Atmospheric attenuation at 5 GHz is pretty minimal. If we conservatively assume 20% loss, I think we still end up with a higher power density at a single frequency than from the sun across the entire spectrum.
I don't think anything like this will ever be built, but I don't see why it is impossible. Where's the mistake?
I beg you pardon, im not arguing for the idea of a earth to moon microwave power link as viable. or sensible. I think it's beautifully insane, i have severe doubts about the actual practicality of such a thing, etc.
But thats the thing: now i want to do a mad max maser on a truck with maybe dozens of magnetrons if i could tow a generator...
It fits with my "Orbital Slingshot" project so well, too.
It's a totally silly idea to built a big ass slingshot that throws things as high as possible. I figure calling it an "Orbital Slingshot" makes it at least as viable and investment worthy as some of the other efforts [1] and [2] forex.
If I can get my daughter to do some artwork I might fire up a web page for it finally.
Hey, please don't break the site guidelines like this. We ban that sort of account.
If you know more than someone else, that's great, but then please share some of what you know so the rest of us can learn. If you can't or don't want to, no problem—but either way, please don't post putdowns.
This thread would be interesting if you would show your work. I'm here for interesting ideas, not people declaring their expertise without educating us.
The only assertions I've made are that im interested in this idea. The assertions the blog post made included a link to another post [1] under the text "I have written more than once about how silly this idea is". referring to "the space-based solar power trope."
One of you is performing some mildly interesting speculation out of confessed limited knowledge. One of you is being rude, insulting, claiming to be the expert, but offering no new information.
One of you is contributing to the thread, at least. It's not you.
The one that the receiver is the most sensitive to. The fact that sunlight comprises many wavelengths is the reason why single-junction cells have comparatively low efficiency.
Direct transmission (e.g., microwave beamed power) might be a more viable alternative. You'd need high towers, and lots of them (smaller radius, nearer horizon), but wouldn't have the mass budget of running wire.
Mining and refining aluminum takes a huge amount of power, so you’re back to hauling tons of wire to build the initial infrastructure. Mining is definitely the way to go after that bootstrap stage, but this question remains: is this the best bootstrap plan?
You have a shitton of solar power at your disposal during the lunar day. Lunar surface is raked by the full solar constant of power, no atmosphere = no attenuation. That is quite a sizzle.
So you can smelt a lot of aluminium during the fortnight when the sun is up. And build a web of wires around the entire Moon so that during the cold and dark lunar night you can get power from the other side of the Moon.
But one of the key observations from this article is that we won't be power constrained, we will be constrained by consistent power, since power at night costs far, far, more than power during the day.
If we can ship some extra solar panels up and refine aluminum during the day, to reduce the cost of power at night, it seems likely to be entirely worth it.
This assumes air and water are solved problems and don't need to be shipped.
Note that oxygen != air. 100% oxygen atmospheres are not a good idea for extended stays.
Nitrogen is not common on the Moon. Nor is carbon (for filtering or other organic applications.)
It's not easy to imagine a lunar base generating >$7bn of returns every year. Apart from space tourism, there isn't a whole lot you can do/build/sell on a moon base that has more value on Earth than it would cost to transport back here.
Of course you could argue Science, and that's fair enough. But literally all the commercial arguments I've seen have been "Something will no doubt appear" - which is possibly not going to win over rational investors.