Science Forums 2

[Moontanman]

Mass Drivers work beautifully in principle, and would work very fine if you wanted to move an asteroid. But it will only work well if you're presented with a homogeneous aggregate of uniform-sized particles. Because what you're doing, in essence, is to use the asteroid for rocket fuel. Bits of it will be launched in the opposite direction of where you're planning on traveling.

You do not have a good idea of how a mass driver would work, no need for a uniform homogeneous aggregate. you put stuff in buckets, you accelerate the bucket and fling the stuff in it out into space, the bucket stays.

So imagine your asteroid is composed of one solid piece of iron/nickel. First, you have to cuts bits off which would be launched to supply you with the necessary thrust. I don't know about mining in space, but mining on Earth (essentially cutting pieces of rock out of the Earth) requires immense supporting industries to supply such mundane items as cutting tools, which have a notoriously short lifespan, given what you intend to do with them.

Again why would you move the asteroid into earth orbit? You refine the metals on site and move the refined metals to the earth. You use the left overs from the refining process as mass for the mass drivers. I can see a huge complex, moving slowly among the asteroids, it moves to an asteroid, refines the metals and starts them to earth with a robot type drive section attached. Then you move the complex to the next asteroid. BTW you make your own cutting tools, lasers and other things make great cutting tools.

Bingo. In my example about all airplanes flying to Antarctica, that would indeed make perfect sense in 1957. Because that would be purely for science. And we've achieved the perfect model for that - with the Mars Rovers. Robotized exploration is the ticket. It's cheap, expendable, scalable, and has vast application on the domestic economy of Earth.

Not to mention highly limited, can you imagine how limited our knowledge of Antarctica would be if we used robotic rovers that cannot be controlled directly for the exploration of Antarctica? It's doubtful we would know 1% of what we do now.

Granted. Fast straight-to-Earth orbits will take enormous amounts of fuel, slow orbits will take much less. But with easy, slow orbits, you're talking years of your resource payload slowly spiraling towards the sun, to be intercepted by Earth. Not to sound too much like a grouch, but commodity supply and demand doesn't quite support that scenario. People want stuff now. A company would rather invest in a mining operation somewhere in Africa that could show a return in a year or two than invest billions in the project you're proposing, which will only deliver a few decades from now.

Not if the potential profits were an order of magnitude higher. Once the "pipeline" was full shipments of refined metals could arrive every few days or weeks. No need to wait years on shipments.

As far as I can recall, you said that atmospheric braking is to be employed. And the reason that decelerating space craft don't hit people's houses with any regularity, is that their reentry is usually controlled by thousands of humans working in concert around the globe to plan, track, command, steer and manage the whole operation. And that is just for a single item coming down from orbit like, say, the Space Shuttle. But what you're proposing is more like Columbia's fatal re-entry, continuously, all around the globe, for chunks of rock big enough so as to not completely ablate during entry. And then there is to be a complete mining industry devoted to picking up the pieces as they scatter and fall all over the world. Two-thirds of your ore will be practically inacessable, seeing as they would fall into the ocean. They would merely serve to pollute the atmosphere, and be gone. I simply cannot see any sense behind it.

Again we are not talking about dropping rocks from orbit, the infrastructure for guiding space craft to the ground is already in place, shipments of refined metals would be brought in just like space craft, to controlled landings, not craters!

Besides, what, pray tell, might be the difference between "raping" the surface of the Earth, and "raping" an asteroid? If I understand your proposal correctly, there might be somebody living on that asteroid, after all?

No one has suggested asteroids have living ecologies, how can you equate chopping up a lifeless rock in space to destroying the ecology of huge areas of the earth?

Quote:
Originally Posted by Moontanman
At some point mining, even mining landfills, will destroy the environment. Such mining and re-refining of the metals contained there in will be just as bad as the original processes were. ]

Can you please elaborate on this assumption?

The metals in land fill have to be refined, things like mercury and pcbs are are released during this process, why do this on the earth when you don't have to?

They were cheap, and paid for by the Wrights themselves. The analogy is not applicable, because what you're proposing in colonising the solar system is dependent on public money. Vast streams of public money, continuously, for centuries. And all of that when we suddenly have to bail out gigantic corporations because something fundamental is broken in our understanding of economics. And that economy will be the underpinning of any succesfull interplanetary venture. If the technology reaches the level where crazy billionaires like Richard Branson can build a colony on Europa using off-the-shelf items, when it becomes private and out of the public domain, when private individuals can fund it (like the Dutch East India Company in the 1600's) then I'd be all for it. And then invoking the Wrights as an argument in favour, might hold water. But using public money, the Wrights simply don't feature.

Please explain what you mean by expense? If you used 25% of what is spent on the military humanity could own the inner solar system in 50 years, easily. at some point the lions share of expense would be shouldered by the colonies themselves. Once you stopped depending on earth for your supplies and resources the expense to the earth becomes moot. And yes i expect a economic system to develop in space independent of the earth. If we used 100% of what we spend on the military could be owning the entire solar system and be starting on the alpha centauri system in 50 years. expense is a relative thing.