Just to be clear, the "vast stores" of water are only theoretical. There are no implications for Moon colonies. You are not going to try to extract water from glass beads. You would need to go through thousands of tons of regolith before extracting a single liter of water, and that's only if you have 100% efficiency, which you will not have.
If we ever decide to have Moon colonies we'll have 3 big problems: we won't be able to source easily carbon, hydrogen and nitrogen. I predict that when we'll have such colonies, the phrase "you're worth your weight in gold" will mean you are useless, since your weight in carbon, hydrogen and nitrogen will exceed many times your weight in gold (which can be sourced locally). Similarly, "you're full of shit" will be a high form of praise, since shit will be thoroughly recycled and highly valuable.
Certainly, getting those elements in larger quantities will be important, but by the time we have the cargo capacity to build colonies on the moon it seems likely that someone would be very happy to trade, say, 100t of Earth-sourced C/N/H for 100t of Moon-mined Au, shipping included.
I don’t expect there to be much in the way of heavy elements on the moon. It’s mostly made of lighter stuff that got blasted off in the collision with earth when the moon was formed.
The surface has been slowly bombarded long after the moons creation. So surface mining could have a very different elemental mix than subsurface mining.
~48.5 tons of material hits the earth’s atmosphere per day. The moons smaller, but suck impacts where likely more common in the past * 4 billion years and you’re talking a few feet of such material across the entire surface. https://solarsystem.nasa.gov/asteroids-comets-and-meteors/me...
Impact sites of larger asteroids are also great targets for mining operations. For example there's some speculation about the gigantic impact crater on the far side of the moon containing a gigantic metal lump below the surface
It's not entirely clear to me why you'd want to find asteroids on the moon rather than finding them in space, where the mass wouldn't hardly have to be lifted.
On paper, it would be easier to lift them from the moon than it would be to intercept and slow them down enough to land them on earth. When the asteroid hits the moon it expends huge amounts of energy in the impact, slowing it to the a near-stop as compared to its speed while free in space.
It may be possible to aerobrake asteroids at orbital velocities in earth's atmosphere, but that is a VERY dangerous proposition. It might work for small rocks, but a commercially-relevant chunk of iron would be a very dangerous object to point at earth.
The problem with asteroids is the population dynamics and time required with these heliocentric orbits. Yes, there are asteroids at a lower Delta-V than the surface of the moon. There might be only a handful that are even worth capturing and mining. If this scaled up, however, you would quickly deplete this population of NEOs.
While the Delta-V might be less, it's not less by MUCH because you spend most of your fuel getting to Earth's escape velocity in the first place. The Delta-V benefit is also balanced against a massive time lag involved in sending a robotic spacecraft to capture and boost it to an orbit where we can better access and refine it. Or you send the refinery to the asteroid for larger asteroids. Problem there - you'll basically have to build a new refinery for each asteroid. Even for larger NEOs at higher Delta-Vs, the mass is not all that much. It's also not clear that microgravity will be any better than 1/6th gravity.
There are very strong arguments for Lunar mining. We're talking about ~1 week for transit time from Earth to there. The moon can build vast Earth-like industry. You get to cherry-pick a wide variety of asteroid material types (except for volatiles) without building a new factory for each. Surface transportation isn't particularly hard. Materials to build solar panels are widely available.
Asteroids will be useful at some point, but only after we can reach the frost line. Otherwise, the asteroids we get will be parched and not offer much beyond what's on the moon, or what we can lift from Earth. After we get to the frost line, we will get vast troves of organic material, but this is at tremendous Delta-V cost and outrageously remote and time consuming to access.
A space elevator is really an optimization in reducing fuel costs for upfront investment. Such a thing becomes attractive past a certain volume of launches.
While it’s never necessary, it will make sense at some point.
Without an atmosphere can use coil guns etc to launch projectiles just as easily. You get more cargo capacity for lower investment and can still operate on solar or nuclear power.
If the moon rotated faster a space elevator might be more interesting but it would just be really slow, expensive, and a large risk if it where to break.
But shipping from the moon to the earth should be much cheaper? I don't have the math (so someone please do?) but based on the size of the Apollo 11, it seems to be trivial to send stuff to earth.
Looking at our handy solar system delta-v map[1] it takes 2.5 km/s of delta-v to get from the Moon's surface to an Earth intercept course (you can aerobrake to a landing) and 14.6 to get up from the Earth surface to the Moon's (no aerobraking, you have to use rockets to land). Also without an atmosphere you can use railguns and such to take off on the Moon, if you get more than a few km/s of boost on the Earth that way you'll burn up.
>> ... based on the size of the Apollo 11, it seems to be trivial to send stuff to earth.
You mean the worlds largest rocket? That machine that launched from the moon first had to be brought to the moon, a task requiring an enormous rocket and untold support structures on earth. Of course one might say "build the rocket on the moon from moon rocks" but that requires significant handwaving. Try smelting aerospace-quality metal in your garage before suggesting that anyone simply park an aluminum smelting facility in a lunar crater.
The machine that does this first has to leave Earth and land softly on the moon before it can start boosting stuff back. You can’t skip the first two steps.
The machine that does this needs to be built by a machine that is carried by the machine that is first built and launched from earth before you can start boosting stuff back.
It is feasible to build a space elevator on the moon with existing materials.
a recent megaprojects video claimed harvesting water from asteroids was more worth the time and money than to do the same for rare earth metals.
apparently bringing tons of rare earth metals back to earth would only lower their price and therefore not make the trip worth the money, but i guess this isn't a problem for the water that those asteroid might hold as that would still be not only valuable but worth the expense of harvesting it from asteroids.
if the moon is closer, and not only less complicated to harvest from but has the advantage that you can keep a permanent drilling rig set up without needing to re-land on a complicated surface every single time, that would seem better than harvesting water from asteroids to me
That seems like a bizarre take. Even with efficient fully reusable rockets, surely desalination will still be much cheaper than mining water from asteroids and bringing it back to Earth?
And sure, maybe bringing huge amounts of rare earth metals back might reduce the price a bit, but to the point where rare earth elements are cheaper per mass unit than water?
If we ever have a space elevator bringing water down from space could actually be a net negative expense, since you could be using the weight to carry stuff up out of the gravity well.
"If we ever have a space elevator" such a simple phrase doing a lot of rhetorical lifting. The logistics and problems of space elevators make them extremely unlikely in any timeframe that is less than fantasy.
it seems bizarre to me too, i'd also think the practical use of having stores of rare earth metals outweighs their initial value simply due to current inaccessibility but i think the video was saying this as a long-term business strategy wouldn't work, as the cost would decrease over time for the initial cost of all the engineering
i'm unfortunately unable to comment on the economics of space water
Seems like the 28 day, uh, day will be a bigger problem. Everything from keeping power on for 14 days without solar to keeping the temperature up to human habitability levels will be challenging won’t it?
It's a different kind of problem. The Moon is a big ball of stuff outside of the Earth's gravity.
If that's stuff is valuable, then the Moon is a very valuable target, and there is a reason to solve problems like the 28 days long day. If that's stuff isn't valuable, then the size of the day is an insurmountable issue.
If we ever decide to have Moon colonies we'll have 3 big problems: we won't be able to source easily carbon, hydrogen and nitrogen. I predict that when we'll have such colonies, the phrase "you're worth your weight in gold" will mean you are useless, since your weight in carbon, hydrogen and nitrogen will exceed many times your weight in gold (which can be sourced locally). Similarly, "you're full of shit" will be a high form of praise, since shit will be thoroughly recycled and highly valuable.