OK, but they're talking about all the oxygen molecules that are in metals. And then digging 10 meters deep for the whole moon, assuming 100% can be extracted and get to the clickbaity number in the title.
Does anyone know how this compares to earth? And what amount of energy is needed to practically make some human usable oxygen?
And water - composing 71% of the earth - is two hydrogen, one oxygen atom. That's just the atoms of water itself, on top of that, a lot of oxygen is dissolved in the water itself.
tl;dr the earth has plenty of oxygen, it's not really a problem. Other gases are though.
The Earth doesn't need this because it has a breathable atmosphere, but you can just look at the oceans and ballpark figure that to about 8/10ths of their mass (the oceans, not the planet).
This is assuming the oxygen is used once then somehow eliminated. In practice that exhaled oxygen, as CO2, would probably be absorbed by plants, e.g. food crops, and recycled into O2.
Also, smelting aluminium takes a lot of power. The Tiwai Point Aluminium Smelter [1] uses 13% of New Zealand's electricity to separate the aluminium and oxygen.
On the plus side for power, on the moon solar panels can operate at maximum efficiency all day every day. Build a network that spans the circumference and you get a reliable power grid.
But even more so near the poles, where there's no need to build transmission lines around the entire circumference to access constant sunlight. Prime real estate for moonbases!
The tradeoff there is that due to the angle of incidence, for a given area of the moon's surface you get a lot less energy. That means angling your panels vertically and spreading them out very widely to capture the same energy as you would at the equator. Or build a huge solar panel wall as high as you can that rotates.
Unfortunately there are a whole host of new limitations, some obvious (no atmosphere) and some less so (moon dust is super abrasive because there's no wind or water to file it down).
Think of the extra-global supply chain disruptions that are possible though. We're talking easier to disrupt than a ship going sideways through a canal.
But when you have to move your panels, it suddenly involves lots of moving parts, that break down and require maintainance, etc.
Because ... microasteroids and co.
The missing atmosphere that gives you more light also do not protect you against countless small projectiles.
But when space is not a problem: I would just use solar foil. Not as efficient per square meter, but can cover much more area with a given volume and weight freight restraint.
> do not protect you against countless small projectiles.
They'll hit you all the same regardless of your movements. A very simple mechanical system that does a full rotation every 28 days would suffice.
If you don't need to import the solar foil from Earth, it becomes a much better alternative. Low maintenance means nobody needs to visit the surface to fix stuff.
Contrast that the asteroid materials/free space situation where the solar collector is made from a polymer film coated with thin films of metals and/or semiconductors to either reflect and concentrate or convert energy.
The title of that article suggests that oxygen is limiting but really you need 4 parts N2, Helium, SF6, or some other inert for one part of O2 if you don’t want everything to burn up. Those large airspaces in the O’Neill colonies are unrealistic for that reason.
H2O is limiting in terrestrial ecosystems and that is true in the rest of the universe. Part of the resolution of the Fermi ‘paradox’ is that most of the life in the universe is outside the frost line where a significant part of most bodies is water. Liquid water is generic in outer solar system bodies and probably some interstellar bodies where it takes tremendous luck for dry inner solar system bodies to have a thin sheen on the surface like we do.
I can picture a ‘Galileo’ on a slightly less cooked Io or more cooked Europa getting hassled by the church about the significance of oxygen in the Earth’s atmosphere. ‘Don’t you know life would be impossible without high levels of radiation?’
We're talking about arrays big enough to circle the moon, that's massive scale. Putting those on the poles will dramatically reduce the radiation you can intercept for a given area, and there's a lot less space at the poles than round the equator, because sphere. For smaller arrays the poles make perfect sense.
Unless the panels you describe can't rotate and always face up, there is no change in the amount of sunlight you get per area between the pole or the equator.
Except, as has already been pointed out, you have to space out angled panels much further apart longitudinally near the poles otherwise they block each other. We're going round in circles on this.
Consider a relatively modest 1km square patch of such a massive array. At the equator this patch will consist of panels laid out flat horizontally relative to the 'ground', with a 10m patch spaced every 10m (no gap). At 80 degrees latitude this patch will consist of panels angled up at 80 degrees in longitudinal strips. Let's say each panel is a square 10m x 10m. If the next strip towards the equator is placed 10m away from the foot of the strip 'behind' it, almost all of the strip behind will be obscured in it's shadow. In fact the strips would need to be spaced about every 60m instead of every 10m. That's 1/7th the density. Instead of 1 sq km of panel area you'd only have 0.14 sq km of panels.
If we circle the Moon, even near the poles, we are talking about many square kilometers of solar panels. Unless energy consumption by our lunar civilization is totally insane, I wouldn't mind some of the panels not generating power in some alignments (half of them wouldn't generate any power half of the time anyway).
If you're transmitting around the night side you could use the extreme cold to help with that. Transmitting when the sun is shining on your grid is another story.
The moon only has a 1.5 degree axis of tilt, so unlike on earth (23.5 degree tilt!) the seasons aren’t super pronounced.
It’s true that there are still short periods of darkness even at the poles, but they’re not months long like on Earth.
Further, you could still access 24 hour sunlight by building a transmission grid with multiple solar panels, but the length of the transmission lines required would be much shorter near the poles.
Here’s an actual visualization of the moons South Pole, a few points might not see months long full dark, but 99% of the area ends up in shadow several weeks. And that scales up to some areas being full dark throughout the year. https://svs.gsfc.nasa.gov/4770
Deep craters aside, the lunar poles get the most sunshine of any points on the moon. Lunar "night" lasts ~29.5 earth days at the equator, but much less, on average, at the poles.
You get similarly extreme cold temperatures (-180C or so) anywhere on the moon during darkness, even at the equator.
You get those temperatures on the surface, but the day and night time temperatures average out underneath the surface. As the moon has no atmosphere, long term human habitation needs to take place under the surface to survive micrometeorite bombardment. Larger impactors throw up huge clouds of debris which then impact across the moon up to the moons escape velocity ~2400 m/s ~5400 mph.
There are some advantages to those temperatures being so consistent, but a compromise location is probably the better alternative.
The big advantage of 'sunlight all the time' makes the pole the trump-card for lunar habitation. At least for the energy collectors. I suppose the energy could be bounced off a satellite to be delivered most anywhere on the moon. So habitation could be elsewhere. That lack of atmosphere has its advantages!
There is also an abundance of He3 in the upper crust of the moon. You could centrifuge that out and use it to fuel a D-He3 fusion reactor (assuming you could make such a reactor work terrestrially, ship millions of tons, and assemble such a facility on the moon).
D-He3 is the lowest temperature aneutronic fusion reaction. Not all fast neutron hardening problems go away because a small cross section of reactions will be D-D even at the higher temperature (and potentially short bursts of higher fast neutron flux if temperature control is inadequate and low). However, most of the energy comes out as fast charged particles, which is open to direct conversion. Ditching the steam cycle is a big deal in terms of plant size and weight.
Another plus, you don't need electricity to make a solar reflective furnace. The lower gravity would be helpful building a field of reflectors or a large arecebo-like dish in a crater.
The moon is a terrible place for solar power. Solar panel efficiency drops by about 0.5 percent per degree Celsius over 25C, which is a real issue when the moons daytime temperature hits 110C (230f) Aka past the boiling point of water.
The day night cycle is almost a month long which means you need extreme energy storage, but daytime temperatures go from colder than the arctic winter to past the boiling point of water. The poles don’t get as hot, but they also get months long night due to the moons axial tilt.
Photoelectric power isn't the only form of solar power.
But no matter how you slice it, that two weeks of darkness is a problem. You're going to need nuclear power up there. Fortunately, most of the objections to it on Earth don't apply up there. Space is already a radioactive hell scape in general, there's nothing alive to kill, there's no (currently-known) mechanisms for waste to propagate anywhere you didn't originally put it, etc. etc. We know we can build fission reactors small enough to put out reasonable amounts of power and fit into a payload of a rocket, since we have vessels powered by them already.
Yes RTG’s are by far more common but there have actually been real nuclear reactors in space. That said cooling during the day is a real though solvable problem.
>Solar panel efficiency drops by about 0.5 percent per degree Celsius over 25C, which is a real issue when the moons daytime temperature hits 110C (230f) Aka past the boiling point of water.
Don't they already handle these extremes in satellite solar panels?
Just align your radiators vertically so their flat surfaces point towards the horizon (ie the void of space). Actually you'd want to slightly angle them such that they are still pointing towards empty space but not at the next radiator over, but still you get the idea.
There are many possible solutions but they all add weight, complexity, and or inefficiency. For example further from the equator the lower the daytime temperature, but also directly translates into a lower subsurface temperature which has it’s own problems for a lunar colony.
The notion of temperature is quite weird on the Moon. There's no air over there, and temperature does not make sense in a vacuum. Or rather, there's some type of temperature, but it does not affect the solar panels, simply because the solar panels of countless satellites work just fine.
One could say that the 110C refers to the temperature of the regolith. But that's only if the regolith is directly exposed to the sun, which obviously will not be the case for the regolith underneath the solar panels. And even if it were the case, you can make the supports of the solar panels to be thermally insulating, and again, since there's no air, there won't be any way for the heat to travel from the regolith to the panels.
It’s not quite that simple as over 2 weeks of sunlight heat conducts a fair distance. Also, the regolith emits IR radiation so a shadow wouldn’t be nearly as cool in the daytime.
That said, there are options simply being further from the equator directly translates to lower daytime temperatures, but that also means lower subsurface temperatures. Really the point isn’t it’s impossible to use solar on the moon, just significantly more difficult than on a satellite.
Yeah, that's what I don't get: if you're going to invest effort and energy into reversing the oxidation of some element, why not choose carbon and decompose CO2? It will require non trivial amounts of energy either way.
> You might be familiar with this if you know about electrolysis. On Earth this process is commonly used in manufacturing, such as to produce aluminium. An electrical current is passed through a liquid form of aluminium oxide (commonly called alumina) via electrodes, to separate the aluminium from the oxygen. In this case, the oxygen is produced as a byproduct.
This is currently not the industrial reality.
Aluminum is typically produced via the Hall–Héroult process which involves a carbon source and emits CO2. (Alternative processes which only emit oxygen are possible, but presumably those are more expensive.)
Interesting, I didn't know this about ISS. I've fought a tiring battle to get my CO2 levels below 500ppm consistently, and it's night and day compared to the 800-1200ppm I used to measure. Can't even imagine what 5000ppm is like!
So, I bought one and it was great, but then randomly the CO2 sensor seemed to stop working after a few weeks. It stayed at the exact same ppm level without changing for a while. I sent an email to customer support and they shipped me a new one for free, and didn't even require me to send back the old one. Haven't had any issues since. I'm pretty happy with it.
Not the OP, but I've been using a model by Awair for a while now (looks like they've released a new product that's a bit more expensive since I got mine).
I work in a very small office shed, and if I leave the door and window closed tight it will quickly get over 2000 ppm (45-60 min). At that point I'm typically feeling more tired, and a bit foggy.
By keeping the window cracked I can keep the readings down in the 800-1100 range, and I feel much better.
Yes. I feel much more alert, but oddly I have a much harder time falling asleep. I've since started regular low-dose melatonin which helps a lot.
In particular I find I am much less groggy in the mornings, and stepping outside doesn't feel like a breath of fresh air.
The changes I made are not options for most. I have an industrial rooftop HVAC unit for a space about 5x larger than my home. The fans run continually and there is no fresh air exchange per se but part of the return duct runs through the attic which is not air-tight, more of an open cavity. I change the air filter every 3 months and keep the returns clean by vacuuming regularly. I try not to close doors to encourage circulation, and my bedroom door had an vent to the hall above it -- not sound or light proof, but doesn't restrict airflow.
The key that I've found is airflow. A closed room and a bunch of fans won't help you, but circulating the air of your entire home will make a big difference. It's important that your home breathes. An airtight home is actually very unhealthy, though heating/cooling is more efficient.
Lastly, cooking is the worst offender for poor air quality. Having a stove-top exhaust hood that actually filters and vents outside is so important. Cooking without exhaust or fresh air can easily bring the kitchen and surrounding areas near 1000ppm in under an hour. I keep my exhaust vent on more often than not and it makes a big difference. Negative air pressure is good: air is pulled in from outside.
Not GP (nor a metrologist) but 50% reduction is surely the important thing anyway, in a home setting, not the absolute figures? I don't think the curve could be much off, since they work by counting particles, so if it's reading high at 800ppm then it should be reading just as high at 500ppm right?
I have tested quite a few against calibrated commercial hardware at this point and they’re not as poorly calibrated for CO2 as you would think. The particulate counts and VOCs are usually only good for comparative measurements from the same device in my experience, and even then the drift is quite large.
I am desperately looking for one for the car, do you have anything to suggest?
Also, I am finding products that seem to require an Android or iOS device to work: no. They must be independent. If they had a webserver, nice idea, but all connections should be unrequired and switchable to off.
Correctly guessed, mainly CO2 (breathing). I did not know that CO can be relevant in the car. But of course, the more is evalued, the better. In fact, for example, I had similar concerns for CO for the house (free flames).
My understanding is that in a car, CO is normally a concern only if exhaust gas is somehow leaking into the passenger compartment.
Unless your car has the fans off and the windows rolled up for a really long time, I'd be surprised if CO2 was something you need to worry about. Maybe if you're sleeping in it with the windows rolled up?
CO in the house is definitely a concern. If you have a fireplace, woodstove, or furnace with a properly functioning chimney, you're unlikely to run into problems AFAIK. But people die every winter because they used a propane grill, or kerosene heater, or gas stove/oven in their house without proper ventilation. Or used a wood stove with ineffective / blocked chimney. So in colder climates having a functioning CO meter seems like a no-brainer.
Exactly. In the car, it may happen in winter that you could be working for some time with little ventilation. You may at some point feel dizzy, and realize you would like a meter to get the feedback that can teach you be more aware of the air quality, to regulate the balance between letting the hot air inside escape and letting the fresh air (both senses) in.
In the house, similar awareness could be beneficial.
But I have not yet found a decent product. It is unacceptable that one is supposed to have a Google account or similar in order to read a ruler or configure a blender.
I'd like to share a thought on this, which you may find helpful. I apologize if it comes across as presumptuous; I'm not good at finding the right wording for this kind of thing. It's a cautionary tale from my own life that may or may not resonate with you.
Sometimes I've had similar lines of questioning. Where it occurs to me that something might be a risk worth addressing, and so I'd better gather data until I'm confident everything is okay or that I'll have a way to notice when the risk becomes real.
Every(?) time I've gone down that route, I later concluded that the concern really wasn't that big a deal, and that I'd just be hyper-focused on it because of anxiety or A.D.D. I.e., in the overall scheme of things, the true risks that deserve priority are pretty evident: good sleep and body weight, exercise, not smoking, keeping my finances in order, etc. I have a tendency to forget those primary issues when I start focusing on something that could, potentially, under some circumstances become a problem.
When I go down those rabbit trails, I end up reading a lot of articles, buying some unnecessary stuff from Amazon, planning for a project that realistically I'd never complete, and just worrying a lot.
If there's any takeaway from all this (for me, at least), it's "don't sweat the (probably) small stuff".
My CO2 sensor self calibrates to show 400ppm as outdoor / minimal concentration. I was very upset to find out that it's not correct. In the last 5 years outdoor concentration rose from ~400 to ~420. Guess my kids won't be able to maintain < 500ppm.
> It's likely that it will either be impossible or prohibitively expensive to keep CO2 levels at normal Earth standards.
I think we shouldn't use orbital space station where space and energy is very constrained as model for lunar base (where space and energy will be quite easy to get by comparatively).
Average person breaths out ~1kg of CO2 per day or ~400 per year [1]. Corn field absorbs ~4000 kg of CO2 yearly per 1000 m2 [2]. The same 1000 m2 field will produce ~4000 ears or 320 000 kcal yearly [3][4]
Assuming 2000 kcal for average person (so 730 000 kcal yearly) - we need 2000 m2 of corn fields to produce food for that person and just 100m2 to absorb CO2 from that person. Food will be a more important constraint in a self-sustaining base.
That means if we build lunar base in the lava tubes (that are often over 300 meters wide and go on for kilometers), we can keep them self-sustainable at density of 1 person per less than 10 meters of the lava tube.
That math seems a bit implausible if you look at it from a closed system perspective. For said 1000m^2 field, it has to get the carbon from somewhere to produce the food, that then powers 6 months worth of activity for said human. If a human via respiration can only provide a tiny fraction of it (per the inverse of the other statement regarding:amount of Co2 absorbed for the field), where does the rest come from? Decaying organic material? Soil? Both of those are problematic closed system wise.
There is a lot of very dubious math in everything from ‘amount of water consumed’ and ‘amount of carbon absorbed’, etc. which if you dig into it really doesn’t add up. This feels like one of them?
You would have to bring in enough carbon for the initial setup. Once you have enough material to grow the first crop, you will decompose previous crops to provide carbon and other nutrients for subsequent crops. In a closed system, none of that is being destroyed. In a real system you will get some losses (absorbtion by structural materials, population growth, leaks, etc) but these would be small compared to the overall amount, and easily made up with resupply at first and mined material over the long term.
It's so ironically steampunk that one of the main things we will supply to space stations at first will be coal :) And that each of them will need a big biofuel-fired powerplant just to produce food :)
That just shows that the actual problem in a base with self-sustaining food production will be the inverse - not enough CO2 to produce food instead of too much of it to breath.
To solve this you need initial biomass (or CO2) and then after the harvest you burn or otherwise decompose everything you didn't eat to close the cycle and get your CO2 (and some of the energy) back.
The easiest way to achieve that initial CO2 concentration would probably be to bring about ~3.5 tonnes of coal per person, burn it with oxygen mined from lunar soil generating energy for your initial base-building (24 MWh of heat about 40% of which you can convert to electric energy) and capturing the resulting 8 tonnes of CO2 for agriculture.
Of course you'd bring reasonably pure carbon, not the cheap dirty stuff we dig from the ground with heavy metals and sulphur in it. Also catalyst would be needed to avoid producing carbon monoxide.
Another concern is how much volume of air we need in these tubes to keep the atmosphere breathable and suitable for enough CO2 to supply plants.
Assume the tube is a cylinder 150m in radius and 10 meter in height (height is horizontal here ;) ). That's 700 000 m3 of air which should weight about 857 500 kg. At 410.28 ppmv CO2 in air we can calculate that 0.0623240117 % of the air mass should be CO2, which is ~535 kg in that 10-meter section of the tube. This is a long way off the 8 tonnes of CO2 needed to grow the plants, but they don't want all of that CO2 at once anyway - so we store the waste plant matter from harvest and burn it slowly over the year to keep CO2 concentration in air breathable.
We could also separate the atmospheres for plants and for people to optimize CO2 ppm for each, but that makes math more complicated :)
Carbon isn't plentiful on the moon's surface so you want to conserve it for long duration missions/permanent habitats. Unfortunately storing it as CO2 in the air isn't great for human health.
You need food production anyway for a sustainable moon base. After the harvest store waste plant matter and burn it over the next season to keep the CO2 concentration in air good for plants and for you. It's a closed cycle if you eat/burn everything you grew each growing season, and you can keep the air CO2 concentration stable by adjusting how much waste matter you burn vs how much CO2 is captured by the plants.
You need about 2000 m2 of corn to feed one person over 1 year and just 100 m2 of corn will capture the CO2 exhaled by that 1 person in 1 year. Assume we live in horizontal lava tubes 300m wide, let's say 10 meters of that tube per person to have some margin of error. That's <535 kg of CO2 in air in that section of the tube and ~8000 kg of CO2 captured in corn planted there the moment before harvest.
It's doable IMHO. At least napkin math checks out.
Corn is a great plant optimized for production per acre. On the moon it may be more beneficial to optimize for carbon stability.
Get plants with a more favorable Edible Carbon::Total Carbon ratio.
A plant that can be harvested continuously would also be beneficial.
The ideal plant may be something simple like grass. We can't eat it, so would need another intermediate step. Possibly Cows or Sheep. These would be grown for milk and not meat.
If you are bringing 8B people to the moon you are transporting some carbon. And O2, and H2, and a bunch of calcium and various spore elements such as some iron and manganese, etc.
pretty sure sooner or later you're going to have to figure out what to do with defunct colonists anyway and disassembling them is not the worst option...
Unless they live forever this will solve itself. At a guess most of the carbon and water that you are consuming has been re-cycled a couple of times already, and I'm pretty sure that at least some of that was part of a human configuration at some point in its past.
If we had the ability to transport large numbers of people to the moon and set up civilisation, we'd probably also have the ability to bring a minable carbon-rich comet or two into lunar orbit or smash them into the surface.
There is no way around that. If you sit down and seriously wargame what a space civilization looks like, in real space with no Star Trek shields, you get some interesting results.
One of the results that is really hard to avoid is that if there is a large-scale space civilization around, using the entire solar system... planets aren't really militarily defensible. Without some sort of technology like shields or something that don't seem plausible, they're just sitting ducks. Following along from there, that tends to mean that the planet-bound are going to try to be very highly controlling of the space civilization for as long as possible. They'll be torn between the high levels of wealth the space civilization is sending back down, which will rapidly become completely necessary to sustain their life style, and the fact that every ship in space is a deadly weapon. If you can get to the asteroid belt in a reasonable period of time, you can accelerate from there at a rate that is going to be uninterceptable by the time it gets to Earth.
There's a reason why there's a lot of sci-fi about the space settlers fighting Earth for independence. It's not a terribly difficult analysis to see that as a highly likely outcome. I've only sketched it here.
(As another for-instance... it becomes highly advantageous for Earth to do everything in its power to make darned sure those space colonies can't survive independently, up to and including full intelligence penetration to kill any research attempt to come up with alternate sources for hydrocarbons or nitrogen or complex manufacturing. But the economics and politics inexorably push towards doing more stuff in space for those in space, because it's a lot cheaper than the shipping costs, and as the space-bound get more wealthy and more numerous, eventually they can start smuggling equipment and find places to extract these resources even so....)
There was some evidence in 2020 that there may be more carbon than we thought on the moon [1]. I don't know if there have been further developments on this.
Hilarious that you people are so brainwashed. Not enough drag to influence the orbit that doesn't show even 1% of the "dark side" ever... But enough to sustain life... Funny how these "discoveries" (falsifications) never need to be on the orbit math for satellites ISS et all... Fake!
The moon’s area is about 38 million km², so that would be ‘only’ about 200 persons/km².
That’s less then I would have guessed (cities can have tens of thousands of people/km²), but still way over the current world average (excluding water areas) of about 15/km².
I tried to look up if nitrogen exists on the Moon, seems like it basically does not. I didn't realize how rare carbon is there either. We'd need to bring a _lot_ of things it seems.
Oxygen is actually pretty inert i.e. non-reactive and therefore safe to breathe in pure form (as aquatic divers do, I believe). The reason for that is most of atmospheric oxygen is composed of "triplet oxygen" referring to its outer shell electron configuration being rather stable. For reactions to occur triplet oxygen first needs to be activated and converted into "singlet oxygen" being rather aggressive chemically. This is a "kinetic" barrier that renders gaseous oxygen pretty harmless. This is also the reason why organic matter on earth does not spontaneously catch fire although CO2 + H2O is always energetically more favorable than every CXHXOX composition.
The best thing is that when you extract oxygen from aluminium, iron, and magnesium oxides is that you get oxygen AND materials to build your spacecraft. All in a place where you can take off much easier than from Earth.
The Moon is the most valuable real estate between Venus and Mars.
I saw a Scott Manley clip earlier about a newish rocket company that was building a launcher using rotational energy (flinging rockets towards space, their idea being that they can do away with the first stage of a rocket entirely). I wonder if a device like that would be able to launch a payload from the moon back to earth without needing fuel (besides maybe small maneuvers / course corrections).
This is a bit more flexible than a rail (which can only throw payloads on a single direction), but the Earth is always more or less on the same place in the sky from the Moon, so a rail /linear induction motor is probably the simplest way to do it. No need to have moving parts and, if the rail is long enough, the acceleration can be quite mild.
For safety, I'd not build it aimed directly at Earth, but require some trajectory corrections not to miss the planet. Otherwise it's just a weapon.
> Everything that is in space and big enough and can be roughly guided
When it's guided, you may be able to see it coming, see the jets for changing trajectory, and it can evade an impactor designed to turn it into a lot of smaller pieces that will burn up in the atmosphere. If it's just a rock covered in F22 paint it'll be a lot harder to see before it hits.
True up until the plasma sheath has burned away the radar absorbant coating and then generates a magnitude or more EMF than the object does at ambient space temperature.
Certainly you can. At that point it is on final trajectory and we simply have to put a missile under the object heading straight up. It depends on the type of rock we're talking about. If it's sufficiently large to be highly destructive upon splintering then we are in the realm of science fiction.
Anybody interested in this should play Policenauts. It is an amazing game by Hideo Kojima of Metal Gear fame. It features lots of details like that about life in space, very fleshed out, and is just altogether one of the best games ever made.
The big advantage of the rotating launcher is that you can aim it towards other targets, not only the Earth. You can take your shuttle from LEO to the Moon and then board the big spaceliner in her maiden voyage (because that's the last time it'll be on a planetary surface) towards Mars.
The better aligned to the desired trajectory you launch, the less delta-V you need to get where you want to be. If we launch a payload and, in order to get to where you want it'll need to do a u-turn, our launcher isn't helping.
We were discussing the installation of these on the Moon as a way to launch spacecraft. A straight rail would be aimed at a fixed point, but a centrifugal launcher could release its payload at any point and send it in any direction (as most interesting destinations in the solar system are on a single plane).
Even if we can sustain many individuals on the Moon it would likely be permanent for them as the long term physiology of such humans would be affected by the low gravity there.
Technically moon has enough oxygen to sustain 8B for indefinite time, while you have energy to convert it. If you're going to use oxygen from rocks, why not use it from CO2 that we produce
somewhat tangential - as a kid I loved science fiction and stories about the next great frontier. it was fascinating, the possibility of limitless exploration and new problems to solve.
perhaps my perspective has been skewed over time (or this concept was lost on my naivety at the time) but now it feels like interstellar colonization is more about an escape hatch for the inevitable end of civilization on earth. we'll destroy (intentionally or not) what we have here, set up shop somewhere else and start the process all over again?
Unlikely. If we have the technology to render dead worlds habitable we have the technology to render even a post-apocalyptic Earth habitable: a fraction of the difficulty, and you save a lot on rockets.
I hope I never see the day when a casual glance at a full moon reveals a large dust cloud from active moon mining obscuring part of the details that I've become familiar with over my lifetime.
I'm not sure the moon needs those type of scars.
Maybe they'll find a way to use an N99 filter dome over their operations.
The progress of man seems so naturally tuned towards destructive outcomes. We bounce from one fucked up scenario to another, each one an attempt to put a band-aid on a gaping wound left by our failure to consider how our technological progress seems to leave us with ever more urgent issues to address to insure our own survival and that of our descendants. Maybe we're the virus that is learning how to defeat the planet's immune system and ultimately kill it.
The surface of the moon is just a bunch of pockmarks left over from a millennia of collisions with other space objects. Is that really something worthy of preservation?
The moon and its near-side features are the single visual landmark shared by literally all of humanity which has ever existed. Many would call it sacred. We preserve all sorts of rocks on Earth which are similarly majestic/significant/sacred, despite being formed by random geological processes. Why not the visual façade of the moon?
I think OP doesn't realise how big the moon is. Those asteroid impacts kick up massive plumes of smoke, but we don't really notice it because the Moon is pretty freakin big.
OP here. Actually not OP, just top of this thread.
I'm actually a geophysicist. I do have a pretty good idea not only of how large the moon is, but of where it is in relation to earth, it's age, common rock types found there, origin theories, its effect on earth, its cultural usage down through time, etc.
In my own work I have used knowledge of tidal effects to help me correct seismic data to optimize subsurface resolution so that companies could determine whether there was a resource there that could be economically exploited.
I appreciate you taking the time to read my original post and to comment. This is exactly the sort of discussion I figured it would generate.
Sorry pal we not a virus we are life. When you see that dust cloud on the moon marvel at the technology required to pull that off rather than the visual indicators that you find disturbing. I love going to Death Valley and seeing the remnants of old gold mines and other activities of past. They are scars to some maybe but not to all.
Got me on that one though I was outside yesterday morning and the smell of wood smoke was very nice. That’s from a guy who has lived through many recent and past smoke filled summers that have been helped along (fueled) by those who wanted to stop progress by halting responsible logging. Their tool? The Spotted Owl. Sorry to see how well that is working out for them.
OP here (actually the top of this thread, not OP on the post). Thanks for commenting pal.
I've had lots of time to marvel at technology in my nearly 40 year oil and gas career. A lot of the work that I did when I started in the exploration end of that industry has now been used, even decades later, to drive exploitation in areas that I came to know and appreciate for their raw beauty and isolation. The rock cycle teaches us geoscientists (I'm a geophysicist) that time changes everything and not even the rocks are forever.
In the grand scheme of things looking down through time it appears that a case could be made for humans being only the latest one of a series of afflictions that earth has endured in the past. No doubt earth is resilient enough to survive and establish a new equilibrium should we manage to deplete enough resources here that we can no longer survive as a species, and like rats escaping a flood, hop on any interstellar flotsam available in a bid to save ourselves from our own technologically-induced suicide.
Sounds like you have had a very interesting career. Congrats on that.
From my limited geological knowledge I presume the earth started off a a molten ball of elements that have partially solidified into what she is today. There have been many heinous things done to her throughout her life and in the end she will end up a big ball of fire as our sun expires. Our impact - both beautiful and ugly alike - on her will be forgotten. Somewhere in that leftover pile of rock will be whatever is leftover from you and I - probably just specks of dust - and likely pals for eternity.
Yessir. If we're really lucky there will be enough energy in that supernova so that we can both be blasted far enough and fast enough for both us specks to catch up to and hitch a ride with Oumuamua as it glides through the universe. Dust speck pals on a cosmic dust bunny, heading for some far-off celestial corner where we can rest, safe from the vacuum of space, watching the worlds go by. Certainly a long, strange trip it will be. Happy trails!
With that in mind, maybe on that journey all of our specks will find useful combinations of interstellar particulates and elements and will become the building blocks of new life somewhere else.
While the whole fiery ending here on earth may be a low spot for us collectively, you have to remember that every local minima is by definition the point after which things start looking up as the next cycle begins.
And virus, plants and animals we kill everyday also qualify for life.
We are happy to kill animals that stray into our gardens, but we convince ourselves we didn’t invade their habitats in the first place and committed a genocide against nature so that we can have some extra space over weekends.
I don't know why people are having such a visceral negative reaction to your post. The near face of the Moon has been since the dawn of humanity the single natural formation visible to and enjoyed by every (sighted) human who has ever existed. Preserving it for future humans seems not only natural, but imperative.
Your needless sarcasm belies the fact that you either missed or are ignoring that the OP's concern was about large persistent dust clouds obscuring major features. Not pockmarks.
You've been here ten years, so I would think you're familiar with HN guidelines [1], but please remember:
> Please don't sneer, including at the rest of the community.
> Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize.
There's a group of folks here that believe we should eliminate all exploration for the sake of ambiguous and vague goals of "preservation". They pop up in every discussion of the future, demanding explanations for why people of whom they have no affiliation should use resources of which they have no ownership for purposes over which they have no reasonable control.
Consider directing your volunteer HN moderation at that absurdity.
Dust clouds won’t happen on the moon due to lack of an atmosphere. You can get a localized dust plume, but not fine particles drifting away for thousands of miles in the manner of, say, the California fires.
I actually considered this with the understanding that any dust clouds would be localized and persistent due to the lower gravity on the moon. The finest fraction of moon dust will remain suspended longer than here on earth and the absence of wind will localize the effects. This suspended dust will over time, blur our view from earth of the areas being actively exploited for minerals, oxygen, etc.
I don't see the practicality of conducting mining operations under a dome to localize and control dust so the machinery being employed will be outside any containment and when you do this on a massive scale to potentially support interplanetary travel you will raise a cloud of dust that will take a long time to settle.
I am opposed to this. Since we are two different people with different life's experiences, you don't have to be.
I think you are making a lot of assumptions about the visibility of any possible dust cloud.
First, you have to take into account size. The smallest feature on the moon that can be seen with the naked eye is ~ 300km in diameter. IF aesthetics are your main concerns, plumes smaller than this should be no problem.
2nd, I don't agree that dust will remain suspended longer. Dust on earth is suspended in the atmosphere, which the moon lacks. On the moon, dust follows a parabolic trajectory, like a thrown rock on earth.
Last, lunar dust is the same color as the lunar surface. like a white cloud on a white background, it would be extremely difficult to differentiate.
I personally think a dust cloud on the moon would be cool, but this is beside the point.
I understand your viewpoint. I disagree that dust from mining on the moon would be cool and that the dust would be mostly invisible. Once mining begins, if the processing is successful and their objectives are met, the operations will most likely scale up and that is when the ability to spot these changes from earth will become easier.
to be clear, We are already talking about a hypothetical scenario where there are 8 billion people living on the moon, and your concern is that the mining could further scale up beyond this?
If you are not interested in engaging further on the technical question of if dust would be visible, or the relative value of aesthetics vs utility, I guess there isn't anything to discuss at all.
Suspension requires an atmosphere! All dust particles on Earth experience a 9.8 m/s² acceleration towards the surface of the Earth, but other forces from the moving gases in Earth's atmosphere around them can easily overcome that for a small particle.
All dust particles on the Moon will experience a 1.62 m/s² acceleration towards the surface of the Moon — which is lower — but there are no gases to stop them. They are on a ballistic trajectory from wherever they they were launched. They will impact the surface of the Moon in fairly short order, unless you launch the dust at orbital or escape velocity (upwards of 2 km/s in both cases).
Even if all dust particles settle in minutes due to lack of an atmosphere, the fact that they will need to continue mining operations indefinitely to sustain their existence means that an observer on earth will likely be able to determine where they are by the permanent changes they make to the moon surface. It only requires one to monitor the moon over an extended time period. The scale of the operation will define how long that time period will be.
A larger scale operation that might provide oxygen or fuel for boosters traveling away from earth might need to operate full-time for extended periods so that mining operations will be creating a cloud of dust constantly and though it may settle slowly, it will probably be detectable.
Since many of the moon mining plans involve using it as a base for operations away from earth it seems unlikely that these operations would be one and done. I think that once you prove that you can satisfy that need for fuel or air to breathe in your operations and processing that it will only ramp up with time as new uses will be discovered.
I could be wrong. It would not be the first time nor is it likely to be the last.
The future: The moon as prison planet. At the top of the gravity well, only the most hardened convicts arrive to serve out their sentences in this new Oz. Put to hard labour mining resources, ceaselessly administered and regulated by the state automatons. Almost all sentences to the moon are one-way.
There's a lot of valuable Helium-3 on the lunar surface. It's very impractical today to contemplate using it, but if materials science ever advanced enough that we could construct a space elevator, it might be feasible to do exactly that because 1 ton of Helium-3 can apparently generate 1.5x the energy of a Tsar Bomba.
I'm reading Peter F. Hamilton's Salvation just now, and Zagreus is used as a kind of penal colony, with global corporations having their own clandestine security forces that rendition anyone that opposes them.
I realize it's an issue for my grandchildren's great grandchildren, but does anyone wonder if future generations will look up at the moon and wonder what their ancestors saw because it's been defaced (moon pun) by mining?
It would also make a great advertising billboard! Imagine looking up at the night sky from anywhere on earth and seeing a giant, glowing Apple or McDonald’s logo carved into the moon’s surface!
You ever wonder what Manhattan used to look like before New York City was built or San Francisco Bay? We’ve leveled mountains mining coal and covered deserts and seas with oil rigs. Unfortunately this is not a new problem for humans.
The moon has no magentic field. There is no protection from cosmic rays, not enough gravity to keep an atmosphere, not for nothing that there is currently no known life there.
Life needs more than oxygen. Why do we keep positioning the Moon as some sort of life boat for when we muck up Earth past the point of survivability?
220 comments
[ 3.1 ms ] story [ 259 ms ] threadDoes anyone know how this compares to earth? And what amount of energy is needed to practically make some human usable oxygen?
tl;dr the earth has plenty of oxygen, it's not really a problem. Other gases are though.
Far less actually. From Wikipedia:
> The total mass of Earth's hydrosphere is about 1.4 × 10^18 tonnes, which is about 0.023% of Earth's total mass
The Earth doesn't need this because it has a breathable atmosphere, but you can just look at the oceans and ballpark figure that to about 8/10ths of their mass (the oceans, not the planet).
Mars would be a better comparison to the moon.
Also, smelting aluminium takes a lot of power. The Tiwai Point Aluminium Smelter [1] uses 13% of New Zealand's electricity to separate the aluminium and oxygen.
[1] https://en.wikipedia.org/wiki/Tiwai_Point_Aluminium_Smelter
Circumference of the moon: 10,921km
Longest power transmission line: 2,543km (Belo Monte-Rio de Janeiro transmission line, Brazil)
So it sounds quite feasible actually
But even more so near the poles, where there's no need to build transmission lines around the entire circumference to access constant sunlight. Prime real estate for moonbases!
What if the moon was just a mining and energy "moon" how amusing would that be.
Without atmosphere, you just point the panel to the sun and you'll get 100% power again regardless of how low the Sun is over the horizon.
Because ... microasteroids and co.
The missing atmosphere that gives you more light also do not protect you against countless small projectiles.
But when space is not a problem: I would just use solar foil. Not as efficient per square meter, but can cover much more area with a given volume and weight freight restraint.
They'll hit you all the same regardless of your movements. A very simple mechanical system that does a full rotation every 28 days would suffice.
If you don't need to import the solar foil from Earth, it becomes a much better alternative. Low maintenance means nobody needs to visit the surface to fix stuff.
Contrast that the asteroid materials/free space situation where the solar collector is made from a polymer film coated with thin films of metals and/or semiconductors to either reflect and concentrate or convert energy.
The title of that article suggests that oxygen is limiting but really you need 4 parts N2, Helium, SF6, or some other inert for one part of O2 if you don’t want everything to burn up. Those large airspaces in the O’Neill colonies are unrealistic for that reason.
H2O is limiting in terrestrial ecosystems and that is true in the rest of the universe. Part of the resolution of the Fermi ‘paradox’ is that most of the life in the universe is outside the frost line where a significant part of most bodies is water. Liquid water is generic in outer solar system bodies and probably some interstellar bodies where it takes tremendous luck for dry inner solar system bodies to have a thin sheen on the surface like we do.
I can picture a ‘Galileo’ on a slightly less cooked Io or more cooked Europa getting hassled by the church about the significance of oxygen in the Earth’s atmosphere. ‘Don’t you know life would be impossible without high levels of radiation?’
Consider a relatively modest 1km square patch of such a massive array. At the equator this patch will consist of panels laid out flat horizontally relative to the 'ground', with a 10m patch spaced every 10m (no gap). At 80 degrees latitude this patch will consist of panels angled up at 80 degrees in longitudinal strips. Let's say each panel is a square 10m x 10m. If the next strip towards the equator is placed 10m away from the foot of the strip 'behind' it, almost all of the strip behind will be obscured in it's shadow. In fact the strips would need to be spaced about every 60m instead of every 10m. That's 1/7th the density. Instead of 1 sq km of panel area you'd only have 0.14 sq km of panels.
It’s true that there are still short periods of darkness even at the poles, but they’re not months long like on Earth.
Further, you could still access 24 hour sunlight by building a transmission grid with multiple solar panels, but the length of the transmission lines required would be much shorter near the poles.
Of course this means seriously low temperatures as in below negative 150 range. https://svs.gsfc.nasa.gov/Gallery/moonpole.html
You get similarly extreme cold temperatures (-180C or so) anywhere on the moon during darkness, even at the equator.
There are some advantages to those temperatures being so consistent, but a compromise location is probably the better alternative.
D-He3 is the lowest temperature aneutronic fusion reaction. Not all fast neutron hardening problems go away because a small cross section of reactions will be D-D even at the higher temperature (and potentially short bursts of higher fast neutron flux if temperature control is inadequate and low). However, most of the energy comes out as fast charged particles, which is open to direct conversion. Ditching the steam cycle is a big deal in terms of plant size and weight.
The day night cycle is almost a month long which means you need extreme energy storage, but daytime temperatures go from colder than the arctic winter to past the boiling point of water. The poles don’t get as hot, but they also get months long night due to the moons axial tilt.
But no matter how you slice it, that two weeks of darkness is a problem. You're going to need nuclear power up there. Fortunately, most of the objections to it on Earth don't apply up there. Space is already a radioactive hell scape in general, there's nothing alive to kill, there's no (currently-known) mechanisms for waste to propagate anywhere you didn't originally put it, etc. etc. We know we can build fission reactors small enough to put out reasonable amounts of power and fit into a payload of a rocket, since we have vessels powered by them already.
https://en.wikipedia.org/wiki/Solar_thermal_energy#High-temp...
Don't they already handle these extremes in satellite solar panels?
That is a very good question, because larger panels would mean more mass and cost more.
So careful balancing of the factors? or a different panel formula?
The notion of temperature is quite weird on the Moon. There's no air over there, and temperature does not make sense in a vacuum. Or rather, there's some type of temperature, but it does not affect the solar panels, simply because the solar panels of countless satellites work just fine.
One could say that the 110C refers to the temperature of the regolith. But that's only if the regolith is directly exposed to the sun, which obviously will not be the case for the regolith underneath the solar panels. And even if it were the case, you can make the supports of the solar panels to be thermally insulating, and again, since there's no air, there won't be any way for the heat to travel from the regolith to the panels.
That said, there are options simply being further from the equator directly translates to lower daytime temperatures, but that also means lower subsurface temperatures. Really the point isn’t it’s impossible to use solar on the moon, just significantly more difficult than on a satellite.
> You might be familiar with this if you know about electrolysis. On Earth this process is commonly used in manufacturing, such as to produce aluminium. An electrical current is passed through a liquid form of aluminium oxide (commonly called alumina) via electrodes, to separate the aluminium from the oxygen. In this case, the oxygen is produced as a byproduct.
This is currently not the industrial reality.
Aluminum is typically produced via the Hall–Héroult process which involves a carbon source and emits CO2. (Alternative processes which only emit oxygen are possible, but presumably those are more expensive.)
https://en.wikipedia.org/wiki/Hall%E2%80%93H%C3%A9roult_proc...
It won't cause lunar warming. But it will still be a problem and require significant energy and other resources.
It's likely that it will either be impossible or prohibitively expensive to keep CO2 levels at normal Earth standards.
See also: the ISS which operates with much higher atmospheric CO2 levels (up to 5000ppm) than would be considered healthy on earth (up to 1000ppm).
I work in a very small office shed, and if I leave the door and window closed tight it will quickly get over 2000 ppm (45-60 min). At that point I'm typically feeling more tired, and a bit foggy.
By keeping the window cracked I can keep the readings down in the 800-1100 range, and I feel much better.
In particular I find I am much less groggy in the mornings, and stepping outside doesn't feel like a breath of fresh air.
The changes I made are not options for most. I have an industrial rooftop HVAC unit for a space about 5x larger than my home. The fans run continually and there is no fresh air exchange per se but part of the return duct runs through the attic which is not air-tight, more of an open cavity. I change the air filter every 3 months and keep the returns clean by vacuuming regularly. I try not to close doors to encourage circulation, and my bedroom door had an vent to the hall above it -- not sound or light proof, but doesn't restrict airflow.
The key that I've found is airflow. A closed room and a bunch of fans won't help you, but circulating the air of your entire home will make a big difference. It's important that your home breathes. An airtight home is actually very unhealthy, though heating/cooling is more efficient.
Lastly, cooking is the worst offender for poor air quality. Having a stove-top exhaust hood that actually filters and vents outside is so important. Cooking without exhaust or fresh air can easily bring the kitchen and surrounding areas near 1000ppm in under an hour. I keep my exhaust vent on more often than not and it makes a big difference. Negative air pressure is good: air is pulled in from outside.
So just curious for my own designs, how certain are you about those ppm numbers you listed?
I'm thinking that the specific CO2 concentrations matter if one wants to relate the readings to various research on human mental performance.
Also, I am finding products that seem to require an Android or iOS device to work: no. They must be independent. If they had a webserver, nice idea, but all connections should be unrequired and switchable to off.
I would have assumed CO2 from the context, but since you mentioned cars I'm wondering if you mean CO, VOCs, and/or PM32.
Unless your car has the fans off and the windows rolled up for a really long time, I'd be surprised if CO2 was something you need to worry about. Maybe if you're sleeping in it with the windows rolled up?
CO in the house is definitely a concern. If you have a fireplace, woodstove, or furnace with a properly functioning chimney, you're unlikely to run into problems AFAIK. But people die every winter because they used a propane grill, or kerosene heater, or gas stove/oven in their house without proper ventilation. Or used a wood stove with ineffective / blocked chimney. So in colder climates having a functioning CO meter seems like a no-brainer.
In the house, similar awareness could be beneficial.
But I have not yet found a decent product. It is unacceptable that one is supposed to have a Google account or similar in order to read a ruler or configure a blender.
Sometimes I've had similar lines of questioning. Where it occurs to me that something might be a risk worth addressing, and so I'd better gather data until I'm confident everything is okay or that I'll have a way to notice when the risk becomes real.
Every(?) time I've gone down that route, I later concluded that the concern really wasn't that big a deal, and that I'd just be hyper-focused on it because of anxiety or A.D.D. I.e., in the overall scheme of things, the true risks that deserve priority are pretty evident: good sleep and body weight, exercise, not smoking, keeping my finances in order, etc. I have a tendency to forget those primary issues when I start focusing on something that could, potentially, under some circumstances become a problem.
When I go down those rabbit trails, I end up reading a lot of articles, buying some unnecessary stuff from Amazon, planning for a project that realistically I'd never complete, and just worrying a lot.
If there's any takeaway from all this (for me, at least), it's "don't sweat the (probably) small stuff".
I think we shouldn't use orbital space station where space and energy is very constrained as model for lunar base (where space and energy will be quite easy to get by comparatively).
Average person breaths out ~1kg of CO2 per day or ~400 per year [1]. Corn field absorbs ~4000 kg of CO2 yearly per 1000 m2 [2]. The same 1000 m2 field will produce ~4000 ears or 320 000 kcal yearly [3][4]
Assuming 2000 kcal for average person (so 730 000 kcal yearly) - we need 2000 m2 of corn fields to produce food for that person and just 100m2 to absorb CO2 from that person. Food will be a more important constraint in a self-sustaining base.
That means if we build lunar base in the lava tubes (that are often over 300 meters wide and go on for kilometers), we can keep them self-sustainable at density of 1 person per less than 10 meters of the lava tube.
[1] https://www.nrdc.org/onearth/waiting-exhale#:~:text=So%20bre....)
[2] https://www.canr.msu.edu/news/corn_fields_help_clean_up_and_...
[3] https://www.quora.com/How-many-ears-of-sweet-corn-are-in-an-...
[4] https://www.nutritionix.com/i/usda/corn-1-ear-medium-6-0.75-...
There is a lot of very dubious math in everything from ‘amount of water consumed’ and ‘amount of carbon absorbed’, etc. which if you dig into it really doesn’t add up. This feels like one of them?
To solve this you need initial biomass (or CO2) and then after the harvest you burn or otherwise decompose everything you didn't eat to close the cycle and get your CO2 (and some of the energy) back.
The easiest way to achieve that initial CO2 concentration would probably be to bring about ~3.5 tonnes of coal per person, burn it with oxygen mined from lunar soil generating energy for your initial base-building (24 MWh of heat about 40% of which you can convert to electric energy) and capturing the resulting 8 tonnes of CO2 for agriculture.
Of course you'd bring reasonably pure carbon, not the cheap dirty stuff we dig from the ground with heavy metals and sulphur in it. Also catalyst would be needed to avoid producing carbon monoxide.
Another concern is how much volume of air we need in these tubes to keep the atmosphere breathable and suitable for enough CO2 to supply plants.
Assume the tube is a cylinder 150m in radius and 10 meter in height (height is horizontal here ;) ). That's 700 000 m3 of air which should weight about 857 500 kg. At 410.28 ppmv CO2 in air we can calculate that 0.0623240117 % of the air mass should be CO2, which is ~535 kg in that 10-meter section of the tube. This is a long way off the 8 tonnes of CO2 needed to grow the plants, but they don't want all of that CO2 at once anyway - so we store the waste plant matter from harvest and burn it slowly over the year to keep CO2 concentration in air breathable.
We could also separate the atmospheres for plants and for people to optimize CO2 ppm for each, but that makes math more complicated :)
https://en.wikipedia.org/wiki/BIOS-3
You need about 2000 m2 of corn to feed one person over 1 year and just 100 m2 of corn will capture the CO2 exhaled by that 1 person in 1 year. Assume we live in horizontal lava tubes 300m wide, let's say 10 meters of that tube per person to have some margin of error. That's <535 kg of CO2 in air in that section of the tube and ~8000 kg of CO2 captured in corn planted there the moment before harvest.
It's doable IMHO. At least napkin math checks out.
Get plants with a more favorable Edible Carbon::Total Carbon ratio.
A plant that can be harvested continuously would also be beneficial.
The ideal plant may be something simple like grass. We can't eat it, so would need another intermediate step. Possibly Cows or Sheep. These would be grown for milk and not meat.
The Apollo took 51hrs to get there, unmanned missions took 4-5 days
Half the books I've read about lunar colonies would probably disagree. :D
One of the results that is really hard to avoid is that if there is a large-scale space civilization around, using the entire solar system... planets aren't really militarily defensible. Without some sort of technology like shields or something that don't seem plausible, they're just sitting ducks. Following along from there, that tends to mean that the planet-bound are going to try to be very highly controlling of the space civilization for as long as possible. They'll be torn between the high levels of wealth the space civilization is sending back down, which will rapidly become completely necessary to sustain their life style, and the fact that every ship in space is a deadly weapon. If you can get to the asteroid belt in a reasonable period of time, you can accelerate from there at a rate that is going to be uninterceptable by the time it gets to Earth.
There's a reason why there's a lot of sci-fi about the space settlers fighting Earth for independence. It's not a terribly difficult analysis to see that as a highly likely outcome. I've only sketched it here.
(As another for-instance... it becomes highly advantageous for Earth to do everything in its power to make darned sure those space colonies can't survive independently, up to and including full intelligence penetration to kill any research attempt to come up with alternate sources for hydrocarbons or nitrogen or complex manufacturing. But the economics and politics inexorably push towards doing more stuff in space for those in space, because it's a lot cheaper than the shipping costs, and as the space-bound get more wealthy and more numerous, eventually they can start smuggling equipment and find places to extract these resources even so....)
[1] https://phys.org/news/2020-05-carbon-emissions-moon-theory-b...
There is also some water on the moon - and some hydrogen we could use to make water.
Now we just need to deal with the temperature ranging from -173,+127 and then we can build a nice moon base.
They are literally scraping top layer and smelting it for aluminium with oxygen as a side product.
https://scholar.google.com/scholar?q=mining+moon+oxygen&hl=d...
"Sillicates." (Emphasis on the "ates".)
Oxygen is an integral part of most rock-forming minerals.
'Nuff said.
That’s less then I would have guessed (cities can have tens of thousands of people/km²), but still way over the current world average (excluding water areas) of about 15/km².
Cuz if it’s just pure oxygen I’m pretty sure that’s not safe.
Only for growing plants, we would have to bring some or extract it somehow?
I tried to look up if nitrogen exists on the Moon, seems like it basically does not. I didn't realize how rare carbon is there either. We'd need to bring a _lot_ of things it seems.
The Moon is the most valuable real estate between Venus and Mars.
For safety, I'd not build it aimed directly at Earth, but require some trajectory corrections not to miss the planet. Otherwise it's just a weapon.
Everything that is in space and big enough and can be roughly guided, can be a devastating weapon.
Which is why I love the idea of peaceful space exploration and am not so happy about the latest developements to arm the space again.
When it's guided, you may be able to see it coming, see the jets for changing trajectory, and it can evade an impactor designed to turn it into a lot of smaller pieces that will burn up in the atmosphere. If it's just a rock covered in F22 paint it'll be a lot harder to see before it hits.
https://en.wikipedia.org/wiki/Mass_driver
First time I heard about it was in:
https://en.wikipedia.org/wiki/The_High_Frontier:_Human_Colon...
There is also an amazing English translation, and a blog on how it was done: https://lparchive.org/Policenauts/Update%2042/
Unless you are talking about launching it at lunar escape velocity directly at earth orbit.
perhaps my perspective has been skewed over time (or this concept was lost on my naivety at the time) but now it feels like interstellar colonization is more about an escape hatch for the inevitable end of civilization on earth. we'll destroy (intentionally or not) what we have here, set up shop somewhere else and start the process all over again?
I'm not sure the moon needs those type of scars.
Maybe they'll find a way to use an N99 filter dome over their operations.
The progress of man seems so naturally tuned towards destructive outcomes. We bounce from one fucked up scenario to another, each one an attempt to put a band-aid on a gaping wound left by our failure to consider how our technological progress seems to leave us with ever more urgent issues to address to insure our own survival and that of our descendants. Maybe we're the virus that is learning how to defeat the planet's immune system and ultimately kill it.
https://www.space.com/34372-new-moon-craters-appearing-faste...
(Not to mention, OP was talking about large obscuring dust clouds. Not pockmarks.)
I think OP doesn't realise how big the moon is. Those asteroid impacts kick up massive plumes of smoke, but we don't really notice it because the Moon is pretty freakin big.
I'm actually a geophysicist. I do have a pretty good idea not only of how large the moon is, but of where it is in relation to earth, it's age, common rock types found there, origin theories, its effect on earth, its cultural usage down through time, etc.
In my own work I have used knowledge of tidal effects to help me correct seismic data to optimize subsurface resolution so that companies could determine whether there was a resource there that could be economically exploited.
I appreciate you taking the time to read my original post and to comment. This is exactly the sort of discussion I figured it would generate.
What value do we place on things that we have all enjoyed and marveled at? Which one or which group of us gets to speak for all of us?
I for one am glad that sentiment no longer prevails.
I've had lots of time to marvel at technology in my nearly 40 year oil and gas career. A lot of the work that I did when I started in the exploration end of that industry has now been used, even decades later, to drive exploitation in areas that I came to know and appreciate for their raw beauty and isolation. The rock cycle teaches us geoscientists (I'm a geophysicist) that time changes everything and not even the rocks are forever.
In the grand scheme of things looking down through time it appears that a case could be made for humans being only the latest one of a series of afflictions that earth has endured in the past. No doubt earth is resilient enough to survive and establish a new equilibrium should we manage to deplete enough resources here that we can no longer survive as a species, and like rats escaping a flood, hop on any interstellar flotsam available in a bid to save ourselves from our own technologically-induced suicide.
With that in mind, maybe on that journey all of our specks will find useful combinations of interstellar particulates and elements and will become the building blocks of new life somewhere else.
While the whole fiery ending here on earth may be a low spot for us collectively, you have to remember that every local minima is by definition the point after which things start looking up as the next cycle begins.
You've been here ten years, so I would think you're familiar with HN guidelines [1], but please remember:
> Please don't sneer, including at the rest of the community.
> Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize.
[1] https://news.ycombinator.com/newsguidelines.html
Consider directing your volunteer HN moderation at that absurdity.
I actually considered this with the understanding that any dust clouds would be localized and persistent due to the lower gravity on the moon. The finest fraction of moon dust will remain suspended longer than here on earth and the absence of wind will localize the effects. This suspended dust will over time, blur our view from earth of the areas being actively exploited for minerals, oxygen, etc.
I don't see the practicality of conducting mining operations under a dome to localize and control dust so the machinery being employed will be outside any containment and when you do this on a massive scale to potentially support interplanetary travel you will raise a cloud of dust that will take a long time to settle.
I am opposed to this. Since we are two different people with different life's experiences, you don't have to be.
Thanks for adding to the discussion.
First, you have to take into account size. The smallest feature on the moon that can be seen with the naked eye is ~ 300km in diameter. IF aesthetics are your main concerns, plumes smaller than this should be no problem.
2nd, I don't agree that dust will remain suspended longer. Dust on earth is suspended in the atmosphere, which the moon lacks. On the moon, dust follows a parabolic trajectory, like a thrown rock on earth.
Last, lunar dust is the same color as the lunar surface. like a white cloud on a white background, it would be extremely difficult to differentiate.
I personally think a dust cloud on the moon would be cool, but this is beside the point.
Thanks for contributing to this discussion.
If you are not interested in engaging further on the technical question of if dust would be visible, or the relative value of aesthetics vs utility, I guess there isn't anything to discuss at all.
Suspension requires an atmosphere! All dust particles on Earth experience a 9.8 m/s² acceleration towards the surface of the Earth, but other forces from the moving gases in Earth's atmosphere around them can easily overcome that for a small particle.
All dust particles on the Moon will experience a 1.62 m/s² acceleration towards the surface of the Moon — which is lower — but there are no gases to stop them. They are on a ballistic trajectory from wherever they they were launched. They will impact the surface of the Moon in fairly short order, unless you launch the dust at orbital or escape velocity (upwards of 2 km/s in both cases).
A larger scale operation that might provide oxygen or fuel for boosters traveling away from earth might need to operate full-time for extended periods so that mining operations will be creating a cloud of dust constantly and though it may settle slowly, it will probably be detectable.
Since many of the moon mining plans involve using it as a base for operations away from earth it seems unlikely that these operations would be one and done. I think that once you prove that you can satisfy that need for fuel or air to breathe in your operations and processing that it will only ramp up with time as new uses will be discovered.
I could be wrong. It would not be the first time nor is it likely to be the last.
https://youtu.be/L5foZIKuEWQ
Longer version: https://youtu.be/JrBdYmStZJ4
Life needs more than oxygen. Why do we keep positioning the Moon as some sort of life boat for when we muck up Earth past the point of survivability?