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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 n
by ericbarrett 4y ago
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!
- ryandrake 4y agoHeinlein 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.
- jelliclesfarm 4y agoTANSTAAFL. And it led the Moonies to a rebellion. And the AI Mike basically kills itself. No happy endings there.
- Thrymr 4y agoThe Moon Is a Harsh Mistress.
- rbanffy 4y ago> equivalent to a small nuke Not necessarily a small one.
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- ericbarrett 4y agoPlugging 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.
- rbanffy 4y ago> at those speeds 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.
- LatteLazy 4y agoI 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...
- cmrdporcupine 4y agoYes, 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.