Kinetic orbital bombardment is utterly worthless from a military perspective.

People tend to have a completely inaccurate view on this because of bad popsci, out-of-context feasibility studies from the 1950s and fiction that just leans toward the "fantasy" on that.

The reasons for this is are very simple:

1) There is no "high ground". Being in orbit does not enable you to throw things "down" for free, thats simply not how orbital dynamics work. All the impact energy you have to pay for up front, and delta-v on some orbital object is almost inevitably more expensive than the equivalent amount of explosives on the ground.

2) Anything launched from beyond earth orbit would be unusably delayed. And telegraphed.

3) The concept does not have a single selling point from a military perspective; not really faster than an ICBM, penetration is limited by newtonian physics regardless of speed and more expensive than just delivering the equivalent amount of explosives (or nuclear payload) via missile.

edit: Yes an interplanetary transport system could be weaponized. But so could the explosives currently used in mining (~tens of millions of tons per year), no one cares.

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andrewflnr 4 hours ago | parent [-]

If North Korea or Iran could hold the world hostage with a threat of a mass-extinction-level event, they absolutely would. Similar for many terrorists of various stripes. Are you sure the control systems of whatever company ends up trying to bring back mass from space will be sufficiently resilient to hacking? I'm not. So, I worry.

And we're not even talking about "orbital" bombardment. We're talking about a continuous stream of material at well above escape velocity, whose delta-V is already paid for. Simply redirecting a few pieces of this stream would not be more telegraphed than any other attack. By the way, are you sure the control systems of the mine owners are resilient to coercion of their executives by "legitimate" terrestrial governments? I'm not. None of your reasons are effective.

The energies are substantially more than mining explosives, with wildly different properties as far as threat detection and mitigation. To put it charitably, that's a quite silly comparison.

Edit: now that I'm thinking about it, maybe the best mitigatiom would be to extrude all the mined material into some other very high surface area shape that can't survive reentry, no matter the mass, but can survive being accelerated for the trip home. Maybe a big long truss, with the engine at one end. And then also limit the payload size.

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pfdietz 4 hours ago | parent | next [-]

Moving 1000 tons of Te back to Earth, and moving maybe 10^14 tons to hit Earth, are rather different capabilities.

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andrewflnr 4 hours ago | parent [-]

1000 tons of Te would only be a fraction of what's brought back by a realistic mining operation. Don't you also want all the platinum and palladium and gold hiding out there? Don't you want the iron for building space habitats? No, we'll bring back as much as we can manage, whether it's availability or transport logistics or fear of attacks that turns out to be the limiting factor.

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pfdietz 3 hours ago | parent [-]

1000 tons is how much Te is mined each year on Earth.

Global annual production of platinum is 180 tons.

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andrewflnr 3 hours ago | parent [-]

How is that relevant to the weaponizability of space mining systems, the thing I was actually talking about?

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pfdietz 2 hours ago | parent [-]

It shows that the claim that space mining enables mass-extinction level events is nonsense. Space mining can involve 11 orders of magnitude less mass annually than the K/T mass extinction impact.

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andrewflnr an hour ago | parent [-]

The bar for mass extinction is much, much lower than the K/T impactor. The bar for widespread human suffering and death is much, much lower again. (edit: the bar for general terrorism is much, much etc.) You and myrmidon keep trying to anchor the conversation around these strawman criteria and mechanisms (i.e. "orbital bombardment", as if that was the topic). I'm sure it's just motivated reasoning but god damn is it hard to distinguish from bad faith argument.

	▲	pfdietz 22 minutes ago \| parent [-]
		> The bar for mass extinction is much, much lower than the K/T impactor. Clearly not, otherwise there would have been many more mass extinctions. In any case, shifting that by a couple of orders of magnitude doesn't save the argument.

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roughly 4 hours ago | parent | prev [-]

What’s your opinion on the US’s MAD nuclear strategy?

	▲	andrewflnr 4 hours ago \| parent [-]
		It's pretty bad. I hate it. I wish there was a better one but I'm pretty sure that ship has sailed. Let's try to do something smarter with space mining.