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Comment: Re: Shut it down (Score 1) 201

That makes some sense - of course, figuring out how to get something to carve platinum out to that asteroid will be the fun part, but I guess if you found just the right orbit that came in closer to the Sun for a bunch of easy power - maybe. Seems more likely than Slashcode ever getting Unicode support, anyhow.

Comment: Re: Shut it down (Score 1) 201

Maybe some of the other grown up Republics in the world can help carry some of the ball.

Japan should handle its own defense. The The Poles, British, French and Germans theirs.

If everyone chips in, then none of us have to be the hated police and tax man.

A heavily armed Europe and militarized Japan - what could possibly go wrong? Well, joking aside, it's for the best. Germany is poised to conquer Europe just by calling in its debts, and Japan is culturally quite distant from 80 years ago. Sucks to be Taiwan, but not everyone can be a winner.

Comment: Re: Shut it down (Score 1) 201

By picking the shape and trajectory, we can have quite good accuracy on where to land the debris. Pick a piece of federal desert land and there you go.

Seriously, the scenario as I understand it is: we'd park an asteroid in a high orbit

Bad assumption right from the beginning. That's a terrible waste of energy. You mine an earth-crossing asteroid. Chunks mined off an earth-crossing asteroid can be put onto an earth-intersecting trajectory with only the tiniest of delta-V (you might have to wait a long time your payloads, but no problem there). The amount of delta-V is so low (dozens to hundreds of m/s) that you wouldn't even need to use a rocket, you could just kick it off with a railgun or similar. Then you don't brake it when it gets to earth - it brakes itself by crossing through Earth's atmosphere ("aerocapture"). There are various optional things one could do with the reentry chunks to assist, such as small rockets for trajectory adjustment en-route or small high-speed chutes to keep the asteroids from completely obliterating themselves on reentry / landing (no need for a soft landing, it's fine for them to hit moving at hundreds of meters per second). Both of these would be dwarfed orders of magnitude over by the mass of the return chunk.

All you, as a mining operation, need to do is get your operation up to the asteroid. You need to be able to mine off chunks, shaped appropriately for optimal reentry, and kick them off onto an ideal reentry trajectory toward your target impact zone - potentially with the various hardware systems described as above, but in the base case, not with anything at all. You need a source of power (solar, nuclear) for mining and to kick your chunks into their Earth-intercept trajectory. And of course you have to deal with a million and one details, starting with how to mine at all in microgravity and what targets would actually have commercially viable quantities of valuable minerals.

Comment: Re: Shut it down (Score 1) 201

Which is why you send as optimal of a size and shape as possible. Note that asteroids normally come in randomly and have random shapes. Humans can have a huge impact on the behavior by choosing an optimal shape and trajectory. And, as mentioned, drogue chutes could be used to further reduce the free fall velocity - not for a gentle impact, simply to keep the velocity down to a level that it won't completely obliterate itself in the atmosphere or on impact.

Comment: Re:I think its gonna be a long long time (Score 3, Interesting) 71

Yeah, but experience with gigantic hypersonic parachutes is also rather limited.

Again, it's really doubtful that there's any show stoppers here. But there's a lot that needs to be done before you can bet a whole mission on these sort of things. There's many thousands of little details that could kill the crew if they go wrong, so the odds of any one doing so must be kept to the tiniest fraction of a percent.

Comment: Re:I think its gonna be a long long time (Score 4, Informative) 71

Except that your terminal velocity on Mars is orders of magnitude higher than on Earth. Decelerate to subsonic then fall and you'll be back supersonic in no time.

I'm sure this is possible to do, but it absolutely requires more research and testing.

Comment: Re: Shut it down (Score 1) 201

You've fallen for the "discretionary spending" sales pitch. This pie chart is a bit old, and still has some war spending that we don't have for 2014, but it's still informative. http://usdebtclock.org/ is up to the minute, and cites every number.

Mostly what the federal government does is mail checks to old and/or poor people. Stuff like infrastructure and NASA is collectively an afterthought, and much (most?) of that is pork. As others have said, our government is a pension plan with a military.

I'd like to see more NASA, more roads, more NSF, more building anything, but that's just not the focus of the federal government these days.

Comment: Re: Shut it down (Score 1) 201

Relative spending doesn't matter the way you think it does. For example, it doesn't matter how much we spent if there's no aircraft carrier in a particular ocean the month we need one, and that requires a fixed minimum count of hulls. We've fallen below that count (and it will fall over time) - now we can pick a few places where we can project power, but as soon as we respond to one crisis, any asshole tinpot dictator can see we're tied up there and can send troops across his border.

All of which is only relevant if we want to be the world's police force, of course. Was it worth the cost, to have 70 years with no large-scale war? I think it was, but we're no longer willing to be everyone else's defense budget. We can continue to protect ourselves, no doubt, but I believe turbulent times are ahead if that's all we do.

Comment: Re: Shut it down (Score 1) 201

Exactly - like I said, just pick someone we don't like, and deorbit all the chunks of asteroid we want to down on them, then just pick up the pieces. :)

Seriously, the scenario as I understand it is: we'd park an asteroid in a high orbit (you wouldn't want it dangerously low), maybe above GEO. Slicing off a chunk of platinum itself takes a bunch of energy, but lets pretend we could use a solar furnace or something (seems plausible). We've still got to change the orbit for a chunk of metal for a high orbit to a reentry trajectory - that's a non-trivial mass of fuel per kilo of payload, right? And the cost of getting that fuel to high orbit is nuts, so the economics don't work. But you're better at this math than I am - what do you come up with?

OTOH, if we start with a CHON asteroid in high orbit, and some automated way to process it into fuel (which I think you'd need to get it into orbit in the first place, but isn't that much of a stretch), then everything changes.

Comment: Re:Shut it down (Score 1) 201

really have a hard time understanding where you get the idea that US is so weak and irrelevant

There's a long distance between "superpower" and "weak and irrelevant", no?

We once had a military to fight "two and a half wars", with simultaneous control of every ocean. That's a superpower. We're at around half that strength now. Our naval power is mostly older hulls, and new capital ships are not being built at replacement rate. We'll still be able to project power, no doubt, but not like we used to. Now responding in strength in one part of the world means leaving "opportunities" elsewhere for territorial aggression. Oh well, everyone kept going on about how we shouldn't be the world's police force, and I guess we won't be - at least not in 2 places at once.

The comment about legacy yet relevant weapons really doesn't make sense to me.

Most of our (expensive) strategic force: large naval vessels, bombers, etc, are mostly older now. As we're building far fewer bombers/carriers/fighters/etc than we used to, that means we have mostly old stuff in service now - but still usable today given our likely opponents (though B1B bombers are easy for current opponents to shoot down, only usable after we've already won, really, and will still be in service for 20 more years). For a reduced mission that will be fine, but it's becoming evident that if Russia of China decides to expand its borders a bit, we'll be writing them stern notes.

Comment: Re: Shut it down (Score 1) 201

It costs more for the fuel to de-obit platinum safely than the value of platinum

Asteroids seem to deorbit pretty effectively on a fuel budget of zero.

Your return chunks of asteroid are their own ablative. Ideally you'd give them as optimal of a reentry shape and trajectory as possible, but you wouldn't brake them, you'd just aerocapture, and then give them just enough of a drogue chute that they don't disintegrate fully on impact.

Comment: Re: stealth (Score 1) 261

by lgw (#48684763) Attached to: Newest Stealth Fighter's Ground Attack Sensors 10 Years Behind Older Jets'

Do you understand the difference between "stealth", the B2's thing, which is "remaining undetected", and "stealthy", the modern thing, which is "no missile lock"?

Everyone understands that you can see F22s and F35s on radar. No one is unclear about this. What you can't do is get missile lock before they do. There are fundamental reasons that missile guidance uses short-wave radar (the original radar, from the 30s, was long wave, and military "over the horizon" and early detection radar still is).

Sure it's an arms race, a literal one in fact. That's normal for, you know, arms. But long-wave missile guidance isn't coming soon.

Comment: Re: Ground Control... (Score 1) 201

First: Why? everything in life is a risk

Because NASA is funded by politicians, who care very much about bad news. When a shuttle crashes there must be congressional investigations! Congresscretters must be seen doing something about it.

"Proof" in mechanical systems is usually demonstrated through redundancy which only gets you so far: Not nearly as far as the engineers are taught...

It's not the engineers who are confused about this. Nor is it the politicians. Both groups understand the situation well.

Comment: Re: Shut it down (Score 4, Insightful) 201

conservatives spend bribing old people with freebies

So Social Security, Medicare, and Federal Pensions (collectively over half the budget) are conservative programs now? Man, when did that happen - I can't keep up with these shifts in the political landscape!

Meanwhile, the defense budget is only 1/6th of the federal budget and falling. The left got their way: America's military dominance is fading. The Pax Americana is ending.
 

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