[Firadeoclus]

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.

[kspacewalk2]

Which will of course tank the price of Au into the oblivion, since it is mostly speculative.

[slashdev]

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.

[Retric]

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...

[wongarsu]

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

https://en.wikipedia.org/wiki/South_Pole%E2%80%93Aitken_basi...

https://www.independent.co.uk/tech/nasa-moon-mass-crater-met...

[whatshisface]

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.

[sandworm101]

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.

[AlanSE]

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.

[Teever]

You can build a solar powered space elevator on the moon with existing materials .

[Retric]

That seems unnecessary as the moon is a vacuum so it’s relatively easy to just to fire something from the surface well past lunar escape velocity.

[soco]

2001 is just one of the zillion movies about a metal lump below the lunar surface...

[csomar]

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.

[Symmetry]

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.

[1]https://i.imgur.com/WGOy3qT.png

[sandworm101]

>> ... 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.

[fastball]

Escaping the moon's gravity well is basically all you need to get stuff back to Earth.

[robotresearcher]

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.

[Teever]

Not quite.

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.

[fastball]

You could build a railgun on the moon and launch stuff back to earth.