The normal argument I see against this is that it's easier to mine nearby asteroids. You can reach them without needing to deal with another gravity well -- both landing your mining equipment and launching the mined material again are expensive and potentially risky.
Getting things down is obviously far less of a problem than getting things up.
The hope is a long run situation where industrial activity is self sufficient enough up there that less stuff has to go up. And most things are just coming down into the gravity well. That's the only way it could ever be economical, or ecologically sensible.
But I'm pretty pessimistic about our ability to execute to get there from here.
I think the problem with getting things down will be political.
Any entity capable of precisely delivering enough mass to survive reentry from lunar orbit is now in possession of a weapon of mass destruction, equivalent to a small nuke.
In the late 50s, the U.S. Air Force considered deploying "rods from God," essentially tungsten telephone pole satellites that could hit silos or other hardened targets at near-orbital velocity. Since they weren't inherently explosive, they skirted the Outer Space Treaty. Ultimately they were considered too provocative to deploy.
Imagine a man-made asteroid with several times that mass, coming in from lunar orbit. I'd guess about 10x the energy of a tungsten rod in low orbit, if it wasn't aerobraked or what not. No state which lacks the capability would be happy about it!
Heinlein explored this in The Moon Is A Harsh Mistress. Anyone with the ability to "violently land" small asteroids and/or large rocks on Earth with location precision will have enormous political power.
Plugging some numbers into wolfram alpha, a 90,000 kg object (about 12 cubic meters of iron, for example) moving at the reentry velocity we'd expect from lunar orbit (10 km/s) would have about the equivalent kinetic energy of a 1kT nuke, which is quite small.
You'd have to lob a really big rock at those speeds to get to the megaton range. (Or from interstellar distances, since energy scales with v^2.) Seems infeasible for a near-future lunar mining op. But it also demonstrates how powerful nuclear weapons are.
It all depends on how fast it can be pushed by the mass driver, but the weapon would need to ingest ~4e+15 Joules to impart a megaton of energy into something.
I wonder if there wouldn't be a point where the impactor would be squashed enough to fuse some tritium, but, then, it's no longer just a kinetic weapon.
I mean, that is already the case for anyone who can launch a satellite. So US, Russia, China, the EU, Iran, India, Israel, both Koreas and Japan. Which helpfully are the only people who could mine in space. So I don't think this is really a limit...
Yes, and in practice dropping such a death rock would be viewed the same as using a nuclear (or mass chemical) weapon, and the response from nuclear powers, etc. would be commensurate.
>Trained as an MIT engineer and NASA geophysicist, with an international law degree to boot, Pinault is a partner at Airbus Ventures, an early-stage venture capital firm focused on planetary challenges.
> early-stage venture capital firm focused on planetary challenges.
Maybe, the ones pushing Helium-3 mining on Moon despite completely obvious challenges (extremely low concentration that no one ever does in terms of mining, fusion being prerequisite, plus it's on the moon) also know something about the moon, space, Helium3 but that didn't stop half the public from buying the BS.
It's like suggesting us commute by fighter jets. Can it be done for a demo? Sure, but the whole concept is total fiction that relys on the publics ignorance on the subject to propagate.
