Science Forums 2

[Boerseun]

Originally Posted by Maddog

Using the concept of a Mass-Driver (material from the rock itself) is move the orbit of said rock to in proximity of Earth (not on it). No need to worry about dodging falling rocks.

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. 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.

Originally Posted by Maddog

This is what NASA does pie-in-the-sky concepts day-in and day-out to justify their existence. Are you saying we should STOP all development ???

That is clearly not what I've said, if you've read my posts.

NASA does some wonderful work, and the best they've done so far included robotic exploration. Consider the Voyagers, the Pioneers, the sequence of Mars Rovers. Apollo could be included in this list as well, if the prime mover for that particular venture wasn't political, which, sorrily, it was. They wanted to prove to the Russians that they've got superior rocketry, and they did. It was very hard for them to justify sending humans to the moon for any other reason, and once they achieved it, it fizzled out.

With "pie-in-the-sky" I mean grandiose ideas that has no justification apart from the fact that it's cool, and has very little practical application.

Originally Posted by Maddog

Recycling is a required solution for the near term if not afterwards. However, its efficiency is not 100% (at best we are 19-22% in capturing across the board, less in some items). So there is No way that Recycling alone will be the answer.

I find it ironic that you're willing to flatly dismiss any future advances in recycling technology, stating that there's "no way" for recycling to be the answer, yet you're putting your faith in grand futuristic schemes dependent on fickle public support?

Let's say recycling technology achieves a 50-60% recycling rate in the next ten to twenty years. How much of your asteroid are you going to cut off to serve as reaction mass? 50%? 60%? While there's a 50-100km thick layer of perfectly mineable resources right under your feet?

Originally Posted by Maddog

The rate of production of Chromium in about 1972
would have the expected of all know world reserves depleted by about the year 2000
because of one item -- the Automobile Chrome plated bumper. In the 80's what did we
do -- almost overnight (w/i 1 yr); stop making Chrome plated bumpers and moved to using plastic resin bumpers on all models.

I'm not too sure how big an impact chrome bumpers might have had on the chromium industry, but I will take your word for it. However, I suspect the poisonous nature of chromium hexaflouride had a bigger impact on Stateside production than the mere availability of the ore. As a case in point, in my town, Hernic Ferrochrome (Pty)Ltd is one of the biggest employers, and one of the biggest suppliers of chromium in the world. They have enough chrome to last for many, many years - with vast untapped seams lying in wait for higher commodity prices. Yet, they use hexaflouride in extracting chromium from the ore - which is the very same they would have to use for any chrome-bearing ore coming from space. Unless you want to ship tons of the stuff to Jupiter so that pure chrome can be shipped back to Earth - which seems highly unlikely in the face of high shipping costs. Either way, hexaflouride will be used, on Earth, to process the ore - regardless of where the ore came from.

Originally Posted by Maddog

This would not have made as much sense in 1903, yet would make perfect sense in 1957 (IGY). This is the major problem I see with you logic.

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. But imagine if the purpose of all flight was just to land in Antarctica? There's no market, any resources to be found there can be found much cheaper anywhere else on the planet (there's vast storehouses of coal in Antarctica, yet there's not a single coal mine to be found - international treaties notwithstanding). I think the logic should be pretty clear.

Originally Posted by Maddog

The needs may be different by the time we are to start moving commerce out to our solar system (w/i 100 years).

You can't reason based on the assumption that this will happen within 100 years. Please read my previous posts where I explain the difficulty of getting viable trade up and running between planets. It will take centuries of committed effort just to get population levels up to the levels required for a self-sustaining economy worthwhile trading with. Remember, trade is a two-way street. A bar of gold costing $1,000 might have made one-way trade worthwhile in the 1600's, when a ship costing $50,000 could carry $1,000,000 worth of the stuff. But what the ship cost $100,000,000,000 and that same bar of gold still cost $1,000? Won't it be more economical to simply get it from Earth? There are plenty, and I mean plenty, of gold-bearing seams that have been shut down because of low prices. Once the prices make it worthwhile, goldmines will spring up around known deposits like fleas on a dog, for many, many years still to come.

Originally Posted by Maddog

I am very skeptical whether a proper convincing argument is even possible when you are so closed off to the possibility. Your mind has already been made up.

My mind is not closed to the idea, far from it. Yet, all I hear is dreamy speculation of "what if" and the inevitability of it. I am yet to hear a single "proper convincing argument" in support of colonising other planets. I would really love to, however. So bring it on.

Originally Posted by enorbet2

Perhaps I was too vague. I am less interested in what can be found and brought back from Space Exploration than what we must learn and develop to muster the capability. From my point of view, and as I mentioned supported by the history of exploration, the exploration is the primary (the cake?) and the spoils (frosting?), secondary.

With that, I agree fully. I see the technological progress towards something like interplanetary or even interstellar human spaceflight as being the offshoots of research done for quite different purposes. For instance, a concept like "hibernation" to make centuries (or even millenia) long spaceflight possible, might very well be the result of medical research in how to make hibernation possible for humans who have to wait for organs to become available, for instance. Research can then be very well justified due to the immediate application it will have on Earth, and it will pay for itself.
Where exploration is the cake and the spoils the frosting, I see it very much in the light of robotic exploration being the cake (we get to explore the solar system for a pittance, relatively speaking), and human interplanetary flight might be the frosting when rocketry and propulsion have developed to the point (in support of expediting robotic exploration) that it might become appliccable to establishing a human presence beyond low Earth orbit.

Originally Posted by enorbet2

I am more of the mind of Carl Sagan concluding that the very struggle to survive such technologies required for inter-stellar travel implies a peaceful society.

With that, I agree fully, too. And that should serve as an indication of where our priorities should lie for the next few centuries. (my bold)

Originally Posted by enorbet2

That alone is a worthwhile and noble goal sufficient to justify the expenditure. Add the rapidly growing problem of over population and it's a given for me, considering the alternative "solutions".

There might be many reasons and justifications for colonizing the solar system, but overpopulation on Earth is not one of them. Some 300,000 more babies are born than people die, each and every day. Yes, Earth's population grows by a million by the morning of every fourth day. So we'll have to launch 300,000 people every day, and that will only maintain the population at the same level. Overpopulation on Earth is a local problem (planetary speaking), which will have to be solved locally.

Originally Posted by Moontanman

Moving things around the solar system is easy as long as you take long slow orbits and it is not energy intensive. Refined metals from any asteroid can be easily moved to Mars or the Earth by simply imparting a small deceleration to it and small motors that add or subtract tiny accelerations as you move it around. You are still thinking fast orbits from one planet to another. If your cargo can take years then you can use very easy orbits.

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.

Originally Posted by Moontanman

As for hitting people houses again you are assuming that these cargoes will just be dropped like rocks from the sky. I haven't noticed any of our decelerating space craft hitting people houses with any regularity.

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.

Originally Posted by Moontanman

So we just continue to rape the planet's surface when we could be getting refined metals from space with out the the pollution and destruction that mining and refining the ever more rarefied deposits of metal on the Earth leave behind?

The first caveman to pick up a piece of flint and chipped it into a knife, was the first miner, or the first to "rape the planet's surface". Mining is nothing new, nor strange. The pollution and destruction that you allude to regarding mining, is an artefact of technology. As technology improves, so too does the pollution and destruction go down. Compare, for instance, an 18th century coal mine in England to a modern day colliery.
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?

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?

Originally Posted by Moontanman

This argument doesn't hold water, the first airplane flights were just for fun, they had no reason nor did they need to have a reason.

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.

Originally Posted by Moontanman

People came up with things for airplanes to do. the airplane wasn't built with wow we need to fly to Europe next year. They were built to see if it could be done. Purpose for the airplane came later.

Rocketry was brougth to perfection by Werner von Braun, who built the V2 for Hitler to bomb London with. Von Braun later helped NASA land on the moon, using in a big way his V2 experience. I think Armstrong & co. should have at least planted a Britsh flag alongside the US flag, for the poor Brits who died serving as a testing range for moon rocket technology. But that's besides the point.

Originally Posted by Moontanman

I think I've given you several, resources, colonies, knowledge, and simple exploration. What else could there be?

And I think I've debunked them all. But for brevity, I will sum up:

1) Resources:
Nada. Every conceivable resource you can find on any asteroid, can be found on Earth, much cheaper, much safer, without the danger of destroying domestic markets as a 1,000 ton lump of pure gold falling out of the sky might do.

2) Colonies:
Colonies would imply that there is something for people to do out there. They can either gather resources, which even if economically viable, can be better, safer, and cheaper, be done by machines. Or, they can gather knowledge, which:

3) Knowledge:
Space-based telescopes, Mars Rovers, the Huygens probe, Voyagers 1&2, the Pioneers, the Venera landers, all of these have returned reams and reams of perfectly usable data without a single human on board. If we land a buggy on Mars and we later whish that the thing had a certain capability we haven't though of, that capability can be included in the next rover. The technology improves. If there's a big budget cut, we can safely shut down the system without any loss of life. Science is pure. Science is the interpretation of data; the gathering can be done by anybody or anything.

Once again, I'm sorry for appearing overly negative. But I haven't heard a single compelling argument in favour of human space flight and/or colonisation beyond low earth orbit. Don't get me wrong, however. I think it will be awesomely and amazingly cool. I think to be a citizen of some far-off planet will be rockingly awesome. But there must be a very valid and solid reason for blowing tons of public money, when we're battling with such issues as falling educational standards etc., for which there might be much better application of said tax monies than to chase resources that is uneconomical, unrealistic, and found right under your feet on Earth, in any case.