Can Asteroid Mining Technology Serve as a Global Defense System?

[thorium1010]

Is it worth spending billions for some technology for deep mining in space. Isn't it easier to bring those asteroids to Earth and then mine it here on earth.

http://www.bbc.co.uk/news/science-environment-17827347

 

[Higgs Boson]

Google Chiefs Back Startup Mining Asteroids for Metals

--- http://www.bloomberg.com/news/2012-04-24/google-chiefs-back-startup-mining-asteroids-for-metals.html ---

It's an interesting article that apparently indicates a lot of big money backing about to be thrown at the problem.

Of course, imho at least, few of them have attempted to do the math ... while thankfully others among us have:

--- http://physics.ucsd.edu/do-the-math/2011/10/why-not-space/ ---

Open for discussion, but imho there are more pressing needs and better ways to spend the money at the moment.

 

[Astronuc]

Is it worth spending billions for some technology for deep mining in space. Isn't it easier to bring those asteroids to Earth and then mine it here on earth.

http://www.bbc.co.uk/news/science-environment-17827347

There's the matter of slowing it down and bringing it to the ground intact.

 

[Containment]

I have a feeling that at first and probably for a long time mining the asteroids will not be "worth it" however the technology developed to do such a thing probably will be more likely to be. Kinda like how going to the moon was not really "worth it" but the technology gained in doing so was more or less.

 

[Ryan_m_b]

I'll believe it when I see it. Sounds like a PR stunt to me, especially the projections of just a few decades ahead. Bear in mind the astronomical (pun intended) cost of the Apollo project just to get a brace of men on the Moon. I can't see a collection of companies wanting to spend the necessary tens of billions of dollars for decades on something that won't really pay off. I say won't really because economically they could invest those billions elsewhere to achieve their goals cheaper and more efficiently. There are plenty of recycling or mining technologies that could be developed and give far greater results.

Going to space to a large extent is ideological. There is really no good economical argument.

 

[wuliheron]

It's pretty clear their only real intention for now is to survey asteroids for their potential mineral contents, and the assumption is that future technology will make the venture cost effective. That's a pretty standard practice. For example, the US and the Russians surveyed Afghanistan for its minerals estimated at over a trillion dollars in value despite the fact no one has figured out to ship them from the land locked country. As prices go up and technology improves, so does the viability of shipping over longer distances. That's just how long term planning works in these modern times where technology advances so fast it would be foolish not to take such things into account when talking about ventures decades in the future. With the kind of money and influence involved in this one you can be sure the government will support them as well.

 

[jim hardy]

I'll believe it when I see it. Sounds like a PR stunt to me, especially the projections of just a few decades ahead.

I'm old enough to remember Howard Hughes' "Glomar Explorer", a cover story for deep ocean venture. The stated purpose was to pick up exotic mineral nodules from seafloor but what they were actually after was a Russian ballistic missile sub sunk out past Hawaii someplace.

What can you hide on an asteroid? Have we already lost something out there?

Where's our poster nsaspook?

 

[D H]

Of course, imho at least, few of them have attempted to do the math ... while thankfully others among us have:

--- http://physics.ucsd.edu/do-the-math/2011/10/why-not-space/ ---

There are always naysayers. Sometimes those naysayers are right. There's no future in tulip bulbs. But more often than not they are very wrong. Sailing to the Americas is a waste of money. There's a world market for maybe five computers. There's no money to be made on the internet.

Open for discussion, but imho there are more pressing needs and better ways to spend the money at the moment.

Since it's private money at stake here, it's really none of your business.

Most of these new space startups will fail. That's the nature of startups. A few won't, and they'll make a killing. That's also the nature of startups.

 

[Jimmy Snyder]

But more often than not they (naysayers) are very wrong.
...
Most of these new space startups will fail.

So which is it? Most succeed or most fail?

 

[Office_Shredder]

So which is it? Most succeed or most fail?

Most fail, but the claim that nobody will succeed is wrong.

 

[Jimmy Snyder]

These guys could save a lot of money on rocket fuel by just camping out in Evo's back yard.

 

[Ryan_m_b]

Sailing to the Americas is a waste of money.

I was hoping our resident space expert would see this thread I agree with you on the general point that we don't really know what tomorrow will bring but regarding this specific point about the Americas (I know you didn't mean it how I am responding to it but it's an interesting point).

I frequently encounter space enthusiasts (I use that term to mean people who grew up idealising John Wood Campbell stories and counting the days until they can move to Martian Domed City One) who compare manned exploration/colonisation of space to the settlement of the Americas. It's an attractive analogy but a deeply flawed one IMO. The cost of building a wooden sailing ship was negligable for a European nation. They also had free life support on the journey, a working ecology when they arrived and their technology base was primitive enough that a few hundred people could fufill the roles prevelant in society. Whatever the future of manned space travel is it will not ressemble this at all.

 

[Bararontok]

Question about Google's plan to mine asteroids

How will the probes send the large quantity of materials back to Earth? Because the news journals do not specify how this will be done.

Sources:

http://www.businessweek.com/news/2012-04-24/google-chiefs-back-startup-mining-asteroids-for-metals

http://news.yahoo.com/asteroid-mining-venture-backed-google-execs-james-cameron-011205183.html

 

[wuliheron]

I'm old enough to remember Howard Hughes' "Glomar Explorer", a cover story for deep ocean venture. The stated purpose was to pick up exotic mineral nodules from seafloor but what they were actually after was a Russian ballistic missile sub sunk out past Hawaii someplace.

What can you hide on an asteroid? Have we already lost something out there?

Where's our poster nsaspook?

That's a good point. A large number of rocket launches would require some kind of explanation to avoid escalating a new arms race. The X37 has been in orbit for over a year now without the public having the slightest clue what it is doing. The Pentagon is soliciting designs for disposable on-demand satellites, working on rocket designs to replace even the Saturn V, etc. while NASA scales back everything. I'd have to say it's pretty obvious the US government is more interested in dominating orbital space at this point then exploration.

 

[Ryan_m_b]

the claim that nobody will succeed is wrong.

That can only be established after the fact. The claim that nobody could succeed is different, all you have to do to falsify that is show that the science and technology are physically possible. Whether or not there will ever be a group that has a motive, will, means and resources is another matter.

 

[russ_watters]

I'll believe it when I see it. Sounds like a PR stunt to me...

I'll believe it when I see it. Sounds like arrogance to me.

 

[russ_watters]

Most fail, but the claim that nobody will succeed is wrong.

I'm still waiting for the first to succeed! SpaceX is almost there, but as cool as it is that they have nearly reached their goal of becoming the first commercial space flight company, it is also a long, long way from being able to mine an asteroid. Just don't make the mistake of believing that if an internet billionaire can get a satellite into space that they can therefore mine an asteroid. They are nowhere close to equivalent tasks. Relative to that, the Spacex guys are just kids playing in a sandbox.

 

[Ryan_m_b]

I'll believe it when I see it. Sounds like arrogance to me.

Indeed, have you seen some of the timescales floating around?

They even aim to create a fuel depot in space by 2020...
...The inaugural step, to be achieved in the next 18 to 24 months, would be launching the first in a series of private telescopes that would search for asteroid targets rich in resources...
...The intention will be to open deep-space exploration to private industry...
...Within five to 10 years, however, the company expects to progress from selling observation platforms in orbit around Earth to prospecting services.

Not only that but apparently the budget is only in the range of millions. Considering the long development struggle that private companies have had even to launch to LEO such figures are optimistic to the point of stupidity. Having said that I'm not ruling out the idea that one day a company might put into orbit some probes that periodically foray out to chip away at nearby asteroids but definitely not within these time scales without orders of magnitude more finnancial commitment (which begs the question why not spend that money on more efficient means of achieving the goals i.e. recycling/mining on Earth).

 

[Aidyan]

I'm old enough to remember Howard Hughes' "Glomar Explorer", a cover story for deep ocean venture. The stated purpose was to pick up exotic mineral nodules from seafloor but what they were actually after was a Russian ballistic missile sub sunk out past Hawaii someplace.

Indeed. And officially the mission that found the Titanic was an oceanographic scientific research, but truth is that it was a cold war mission to look after a nuclear submarine wreck. The Titanic was discovered only because they had some time left to look after it.
But having said that, I don't know what kind of interest military could have in asteroids... do they?

 

[thorium1010]

Not only that but apparently the budget is only in the range of millions. Considering the long development struggle that private companies have had even to launch to LEO such figures are optimistic to the point of stupidity. Having said that I'm not ruling out the idea that one day a company might put into orbit some probes that periodically foray out to chip away at nearby asteroids but definitely not within these time scales without orders of magnitude more finnancial commitment (which begs the question why not spend that money on more efficient means of achieving the goals i.e. recycling/mining on Earth).

...The inaugural step, to be achieved in the next 18 to 24 months, would be launching the first in a series of private telescopes that would search for asteroid targets rich in resources...
...The intention will be to open deep-space exploration to private industry...

I Think the only reasonable idea and goal that could be acheived is exploration and surveying asteroids. And the time scales they predict would not be sufficient for it. However it is one small step better than nothing (i.e. surveying asteroids). As to claims such as deep space mining they could decades even if they don't factor in recession. 0What would be the payoff. Companies don't invest in technologies that mature decades later . what is a reasonable time for a silicon valley start up to show profitability ? I think that should answer the question.

 

[Ryan_m_b]

Indeed. And officially the mission that found the Titanic was an oceanographic scientific research, but truth is that it was a cold war mission to look after a nuclear submarine wreck. The Titanic was discovered only because they had some time left to look after it.
But having said that, I don't know what kind of interest military could have in asteroids... do they?

Apart from the fact that this would violate Article IV of the Outer Space treaty there is no military advantage beyond orbit. Putting my moderator hat back on let's ensure that we don't head down the road of space/military conspiracy.

 

[Ryan_m_b]

I Think the only reasonable idea and goal that could be acheived is exploration and surveying asteroids. And the time scales they predict would not be sufficient for it. However it is one small step better than nothing (i.e. surveying asteroids). As to claims such as deep space mining they could decades even if they don't factor in recession. 0What would be the payoff. Companies don't invest in technologies that mature decades later . what is a reasonable time for a silicon valley start up to show profitability ? I think that should answer the question.

I agree it is a good thing if the technology is developed. A major caveat to this for me though is whether or not it is the best way of achieving the goal of acquiring further resources. There are plenty of technologies on Earth (many that may benefit from this investment anyway) that could achieve this without the complication of going to space. Only a few years ago the material resources of Afganistan were estimated to be worth somewhere near $1 trillion but at the moment they are innaccessable due to economics. Why not work towards improving technologies (possibly automated) for mining on Earth?

Not to get too off-topic but ideally I'd like to see investment in better technologies, again possibly automated, for mining on land and sea as well as recycling. It would be great if we could send relatively cheap bots into a landfill site and have them (perhaps with a factory as well) strip everything down to component parts. Such technologies would also be a boon towards any effort for automonous in-situ resource allocation for a space mission whose justification is essentially ideology. In other words invest in Earth based technologies that may have space applications rather than the other way round.

Of course it's private money so they can do what they like with it but that's still my desire eitherway.

How will the probes send the large quantity of materials back to Earth? Because the news journals do not specify how this will be done.

Sources:

http://www.businessweek.com/news/2012-04-24/google-chiefs-back-startup-mining-asteroids-for-metals

http://news.yahoo.com/asteroid-mining-venture-backed-google-execs-james-cameron-011205183.html

I don't think there are any firm designs yet but the impression I get is that the probes scavange fuel from the asteroid so as to return with supplies.

 

[georgir]

How will the probes send the large quantity of materials back to Earth? Because the news journals do not specify how this will be done.

The mined asteroids will be in near Earth orbit, so any "sending" will mostly consist of "falling" :p
Granted, successful and safe reentry is not as trivial as I make it sound, but it is still uncomparably cheaper than the opposite - launching a payload to orbit.
Speaking of which, what makes you think they will even want to land the materials at all? They can instead just make use of them in space, saving us the huge expences that launching the same materials from Earth would involve. Of course, making use of minerals or metals directly in orbit is clearly a very long-term prospect, but so is the whole idea of the new organization. And at the same time water and fuel can also be "mined" from some asteroids, and these can be put to use right now.

 

[Astronuc]

The mined asteroids will be in near Earth orbit, so any "sending" will mostly consist of "falling" :p
Granted, successful and safe reentry is not as trivial as I make it sound, but it is still uncomparably cheaper than the opposite - launching a payload to orbit.
Speaking of which, what makes you think they will even want to land the materials at all? They can instead just make use of them in space, saving us the huge expences that launching the same materials from Earth would involve. Of course, making use of minerals or metals directly in orbit is clearly a very long-term prospect, but so is the whole idea of the new organization. And at the same time water and fuel can also be "mined" from some asteroids, and these can be put to use right now.

Some materials (namely those of the Pt-group) would be returned to earth. Others would remain in space for application to structure or as fuel or as water.

The idea of mining asteroids and the moon has been around for decades, and there are numerous symposia and reports on the subject.

 

[dodo]

What I understood from the press conference is that the mining will concentrate mostly on (a) water, which is intended to stay in space, and (b) minerals that are extremely rare on Earth but presumed frequent on asteroids, i.e. platinum; for the latter, it was mentioned that it is one of the few materials which cost more than the price to put them in orbit. It doesn't sound like large volumes need to be brought back to Earth for the business to be profitable.

Edit: Astronuc just got ahead of me. :)

 

[Ryan_m_b]

Some materials (namely those of the Pt-group) would be returned to earth. Others would remain in space for application to structure or as fuel or as water.

The idea of mining asteroids and the moon has been around for decades, and there are numerous symposia and reports on the subject.

What I understood from the press conference is that the mining will concentrate mostly on (a) water, which is intended to stay in space, and (b) minerals that are extremely rare on Earth but presumed frequent on asteroids, i.e. platinum; for the latter, it was mentioned that it is one of the few materials which cost more than the price to put them in orbit. It doesn't sound like large volumes need to be brought back to Earth for the business to be profitable.

Edit: Astronuc just got ahead of me. :)

One wonders why mining sites of asteroid impacts doesn't get quite so much attention. It would also be interesting to see where the Moon factors into this, it's a lot closer and also has minerals rare on Earth. Though public campaigns against Moon mining would probably be greater than that of asteroids.

 

[Astronuc]

One wonders why mining sites of asteroid impacts doesn't get quite so much attention. It would also be interesting to see where the Moon factors into this, it's a lot closer and also has minerals rare on Earth. Though public campaigns against Moon mining would probably be greater than that of asteroids.

Certainly places like Sudbury (a large nickel deposit) are well known. It's Pt-Rh-Pd and associated elements that are rather rare and are of most interest.

These folks have been interested in the subject of a long time.
http://www.planetary.org/home/
http://www.lpi.usra.edu/

The subject has been considered at symposia such as the Symposium on Space Nuclear Power and Propulsion and successor programs, e.g., STAIF and NETS, as well as AIAA meetings and others. Somewhere I have one of the older reports.

Back in the 1980s there was a NASA/USRA program to support graduate students in reviewing and possibly reviving the work done from the 1950s through 1970s in various areas of aerospace and nuclear technology. Part of that was looking at new technologies to realize things like colonizing the moon, mining asteroids and missions to Mars.

 

[russ_watters]

Indeed, have you seen some of the timescales floating around?

Not only that but apparently the budget is only in the range of millions. Considering the long development struggle that private companies have had even to launch to LEO such figures are optimistic to the point of stupidity.

These people are not stupid, so what are the other possibilities?

These numbers simply may not be serius. They may be a publicity stunt designed to see if they can scare-up some investing.

 

[russ_watters]

What I understood from the press conference is that the mining will concentrate mostly on (a) water, which is intended to stay in space, and (b) minerals that are extremely rare on Earth but presumed frequent on asteroids, i.e. platinum; for the latter, it was mentioned that it is one of the few materials which cost more than the price to put them in orbit. It doesn't sound like large volumes need to be brought back to Earth for the business to be profitable.

What do you consider "large volumes"? Platinum and gold are worth about $25,000/lb. If they can put $10 billion into development and spend $10,000/lb to recover it, it would take 666,667 lb to break even.

And I consider those numbers absurdly optomistic.

 

[Ryan_m_b]

These people are not stupid, so what are the other possibilities?

These numbers simply may not be serius. They may be a publicity stunt designed to see if they can scare-up some investing.

Probably a combination of PR for show and to gauge the feedback from investors.

What do you consider "large volumes"? Platinum and gold are worth about $25,000/lb. If they can put $10 billion into development and spend $10,000/lb to recover it, it would take 666,667 lb to break even.

And I consider those numbers absurdly optomistic.

A bit of googling tells me that 666,667lbs is nearly 5 times global annual consumption. Even if they did achieve that the flooding of the market would most likely massively deflate the value.

 

[D H]

It would also be interesting to see where the Moon factors into this, it's a lot closer and also has minerals rare on Earth.

It's much more expensive in terms of Δv to go to the surface of the Moon than to go to the surface of a near-Earth asteroid. It's similar much more expensive to come back from the surface of the Moon than from to the surface of a NEO.

The Moon can factor in, however. It can make the trip to and from a NEO even cheaper if the vehicle steals some momentum from the moon via a gravitational slingshot. Using the Moon in this way could make the required Δv to the NEO less than Earth escape velocity.

Though public campaigns against Moon mining would probably be greater than that of asteroids.

Yeah. That fragile environment of the Moon needs to be protected.

 

[Ryan_m_b]

It's much more expensive in terms of Δv to go to the surface of the Moon than to go to the surface of a near-Earth asteroid.

Ah cool, good to know

Yeah. That fragile environment of the Moon needs to be protected.

It's not a case of environment, Antarctica has a fairly sparse ecosystem but it's a global reserve. There was a debate at my undergraduate university about the exploitation of space and there was a strong movement for keeping the Moon in a similar state. I'm not saying I agree but highlighting the issue.

 

[NeoDevin]

Many of the investors in this project are not looking for an ROI in the next few decades. Larry Page and Eric Schmidt have a history of investing in projects because he thinks they are exciting, of benefit to society, and may pay off in the long run (see: automatic cars for example). James Cameron recently financed his own trip to the Marianas Trench. Charles Simonyi is a repeat space tourist. All of these people have a history of spending huge amounts of money on things they think are exciting, beneficial for humanity/science, and/or have a small chance of paying off huge in the long run.

One of the founders, Peter Diamandis, founded the X Prize foundation. Both founders, Diamandis and Eric Anderson, are aerospace engineers and founded the company Space Adventures. They have experience making money from space technology (I believe Space Adventures has been profitable so far, but can't find any details).

Further, all the calculations earlier in the thread assume only one source of income. Their first intention is to 'produce' water (and probably other chemicals, maybe they can find a source of fuel) in space for other (government) space programs, to save them having to bring their own. This alone may be profitable in the long run, though probably not a very good ROI. Following that they intend to mine for stuff to return to Earth. If they intended to make their entire ROI from mining platinum, as pointed out above, they would flood the market and drive down the price, and it wouldn't work. However, there are other rare minerals that can be mined as well. It may be possible to produce net profit without flooding any particular market, especially when combined with the sale of water and other chemicals to other space programs.

All of that is in addition to the fact that they get patents on all the technologies they develop along the way. Robotics, automation, aerospace, mining, telescopes, maybe some radiation shielding. Any of these technologies can have more immediate applications here on Earth. They can either spin off other companies along the way, or license the technology to other companies. Given that virtually every technology that needs to be developed for asteroid mining has direct and immediate applications in existing markets, it could end up being profitable even if they never bring back so much as a drop of water.

In summary: I think it's likely that this will work, in the sense that they will eventually bring something back from an asteroid. They have enough money behind it, from people who are not averse to risky, long term investments in exciting new technologies, and enough different avenues for producing revenue for it to work. That's not to say that the investors won't lose a lot of money in the process (or possibly just make less than they would in other more conventional investments), but they all have the money to lose.

My only concern is with the company name, Planetary Resources: It sounds just vague enough to be straight out of a distopian sci-fi movies. Kind of like Umbrella Corporation, Omni Consumer Products, Buy 'N Large, or the Soylent Corporation.

 

[Higgs Boson]

Reality check for asteroid miners ...

http://cosmiclog.msnbc.msn.com/_news/2012/04/24/11375462-reality-check-for-asteroid-miners?lite

But hey! Their website is already up and running - at least that's a start ...

http://www.planetaryresources.com/

Excerpted quote from the MSNBC article linked above:

"There's a significant probability that we may fail," company co-chairman Eric Anderson acknowledged during today's big reveal at Seattle's Museum of Flight.

At least two things are certain: Planetary Resources is already bringing in income, and it's intending to launch real hardware within two years. "This company is not about paper studies. ... We're not just talking about it. We've done enough of that," Anderson said.

 

[Arch2008]

The trick is to create an industry to do this as you go. We already know how to launch spacecraft to NEO. Build a small fleet of more efficient Shuttle 2.0 craft and pay for the trips by carrying commercial satellites to orbit. The first missions also carry the modules of a modest space station where the deep space vehicles will be assembled by crewmembers. The space station could also have a space tourism hotel module to pay for itself. The booster pods for the now defunct shuttles were perfect for these kinds of constructs but were foolishly allowed to burn up upon re-entry. So the bottom line start up cost is relatively low and doesn’t require any new technology.

Next, a simple group of automated probes go do a recon of which asteroids you should mine first. This survey would then be followed by a larger probe that nudges the target asteroid into NEO where the raw materials are extracted. The probe could use pellets made from material on the asteroid itself and shot out of a rail-gun on the probe to provide the thrust. A solar sail could deploy the probe to the asteroid, so once again, low cost and existing tech. Silicon from the Moon can be fused in solar powered kilns on the space station to make ceramic re-entry tiles. A simple re-entry pod could be constructed in orbit and used once per cargo load sent to Earth. The tiles might even be sold as souvenirs, since they were “Moon rocks”. As the asteroid u-haul process gains momentum, more ambitious programs could be funded. Once it starts, there’s really no reason to stop at one trillion dollars. A ten mile diameter nickel-iron asteroid has more ore on it than has been mined on Earth in all of history.

Spaceward ho!

 

[D H]

A ten mile diameter nickel-iron asteroid has more ore on it than has been mined on Earth in all of history.

The subject of this thread, Planetary Resources, is not talking about mining nickel or iron. Mining nickel or iron simply is not feasible yet, and won't be for a long, long time.

This thread (and this site) is not the place for fanciful scifi dreams.

 

[Ryan_m_b]

This thread (and this site) is not the place for fanciful scifi dreams.

AKA near-verbatim reiterations of the Mars Trilogy

 

[Higgs Boson]

The subject of this thread, Planetary Resources, is not talking about mining nickel or iron. Mining nickel or iron simply is not feasible yet, and won't be for a long, long time.

This thread (and this site) is not the place for fanciful scifi dreams.

Sooooo ... exercising one's imagination is verboten around here, these days, Delta Hotel?

 

[redrum419_7]

Sooooo ... exercising one's imagination is verboten around here, these days, Delta Hotel?

Apparently so.

 

[Ryan_m_b]

Sooooo ... exercising one's imagination is verboten around here, these days, Delta Hotel?

Apparently so.

Of course not, speculation and imagination are welcomed. So long as they stay within the rules. Arch's post would have been acceptable if he backed anything he said up with some actual science to validate his points rather than just wishy-washy SF claims. For example: what are the potential candidates for a space shuttle replacement and is there a business argument for their production? Could a single space tourist module on a small space station pay for the program? What are the energy costs of propelling large fuel tankers to space and how are they suitable for spacecraft construction? etc etc etc.

 

[lpetrich]

Asteroid mining? Seems like a nonstarter. I seriously suspect that there won't be much by way of ore deposits in the asteroid belt, because of the lack of geological activity in most asteroids. To see why, let's review how how ore bodies form. Geologists have now gotten a good understanding of that, and we can use that understanding to see what one can expect of elsewhere.

Ore genesis - Wikipedia
Processes of Ore Formation

• Fractional crystallization of magma bodies.
• Sorting of immiscible components of magma bodies.
• Hydrothermal processes: water dissolving some minerals in hotter rocks and those minerals precipitating out in cooler rocks.
• Diffusion of minerals into cracks and the like ("lateral secretion").
• Precipitation from bodies of water, like salt being left behind when water evaporates.
• Mechanical sorting.
• Being left behind by other materials getting leached away by water flowing through.
• Release by volcanoes.

Most of these processes require liquid water, and only the Earth and Mars have such processes near their surfaces. There is even some evidence of such processes on Mars, in the form of evidence of carbonates and sulfates.

So we are stuck with igneous processes, rock melting. By the square-cube law, only a relatively large object can have such processes, so have any asteroids had them? The evidence, surprisingly, is yes. Certain meteorites, the "HED meteorites", have spectra similar to Vesta's surface, meaning that they likely came from Vesta.


So the smaller asteroids are unlikely to contain useful ores, except perhaps if they are fragments of some larger one that had had magma differentiation.


One could get the rarer elements by chewing through large quantities of asteroid, but it would be cheaper to do that with Earth rocks or seawater. But there *might* be some elements where mining asteroids might be worthwhile: the rarer "siderophiles". These are elements with a chemical affinity for iron, like gold and the platinum-group elements. The Earth's crust is depleted in them relative to stony and especially to iron asteroids, so one could mine gold by chewing through some iron asteroids.
Goldschmidt classification - Wikipedia
Mineralogy Notes 3
Abundances of the elements 3.1.3

 

[Aidyan]

But would it not be less costly to mine a very small asteroid (say only few dozens of meters wide) ON Earth than mining it in space? One has to de-orbit it, splash it into the ocean and retrive it. Then we can mine it easily at home. Obviously safety is the big issue here, if it wrongly hits a city it is a disaster. But I think atmospheric reentry is a complex but not impossible science.

 

[D H]

But would it not be less costly to mine a very small asteroid (say only few dozens of meters wide) ON Earth than mining it in space? One has to de-orbit it, splash it into the ocean and retrive it.

No. Nobody sane is discussing the concept of de-orbiting an asteroid. Think about it.

 

[SHISHKABOB]

basically: you'd need A LOT of energy to take something going many km/s and slow it down to zero along with the energy needed to compensate for gravitational potential energy

it'd be silly

 

[thorium1010]

No. Nobody sane is discussing the concept of de-orbiting an asteroid. Think about it.

It maybe a silly/insane question .why is it impossible to bring small asteroids back to earth?
would it destabilise the asteroid belt or we cannot control the velocity it enters Earth's atmosphere. Or the energy required is too great for it to viable.

 

[SHISHKABOB]

It maybe a silly/insane question .why is it impossible to bring small asteroids back to earth?
would it destabilise the asteroid belt or we cannot control the velocity it enters Earth's atmosphere. Or the energy required is too great for it to viable.

it's because you're talking about taking a GIGANTIC ROCK from *space* to the *ground* without it just crashing and blowing some stuff up

we don't even have our spacecraft re-enter the atmosphere at slow speeds. How do you suggest we give an asteroid a "soft landing"? It's a totally unpractical idea.

also: no it wouldn't destabilize the asteroid belt, the only thing stabilizing the asteroid belt is the sun

 

[lpetrich]

It's possible to work out the numbers -- soft-landing an asteroid is TOTALLY impractical. Let's see what one needs to do.

-

This asteroid will be accelerated by the Earth's gravity, and when it reaches the Earth's atmosphere, it will be traveling at a little over the Earth's escape velocity, about 11.2 km/s. How much propellant will one need to consume to soft-land it?

Over a century ago, Konstantin Tsiolkovsky showed how to find how much. His rocket equation, for initial mass m_i, final mass m_f, effective exhaust velocity v_e, and velocity change v:

v = v_e * log(m_i/m_f)

Relation to specific impulse: v_e = I_sp*g_E, where I_sp is the specific impulse, and g_E is the acceleration of the Earth's gravity at its surface, about 9.81 m/s^2.

So to avoid consuming much more propellant than asteroid, the rocket must have an exhaust velocity more than the Earht's escape velocity.

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The asteroid must be supported by the rocket engines as it makes its landing. That requires that the thrust be greater than (asteroid mass)*g_E.

So for a thousand-ton asteroid, that requires a thrust of a million kilograms-force or 10 million Newtons. Bigger asteroids require more thrust, of course. I won't get into English-system mass and force units.

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So let's see what's available. Spacecraft propulsion - Wikipedia has a big compendium of numbers in its "Propulsion methods" table, and Wikipedia's articles on various rocket engines often list the engines' numbers.

The highest-thrust engines that have been successfully run are chemical-combustion ones, at 1 to 2 million Newtons, and hydrogen-oxygen ones can get about 4.5 km/s of exhaust velocity. Ones with non-cryogenic propellants can get as much as 3 km/s. Because of the nature of their energy sources, it's difficult to get much more exhaust velocity than that.

So they are unsuitable.

One can get more energy per unit mass with nuclear reactions, and thus greater exhaust velocity, but there are problems here also. A nuclear reactor heating hydrogen can get around 9 km/s or thereabouts, which is still too low to be suitable. It cannot get much more than that without melting the reactor. Nuclear-bomb propulsion can get greater exhaust velocity, but it has certain other problems. Inertial confinement fusion would also get high exhaust velocity, but that mechanism has yet to produce energy breakeven in the lab.

So they are unsuitable also.

In contrast to these thermal systems, there are various nonthermal propulsion systems, like ion engines, that are in various stages of development. The Dawn spacecraft , currently at Vesta, has 3 ion engines, each with exhaust velocity 30 km/s and thrust 0.09 Newtons. Most other nonthermal engines have similarly low thrust.

These are still more unsuitable ones.

So there's no way that soft landing an asteroid is going to work.

 

[Higgs Boson]

So there's no way that soft landing an asteroid is going to work.

Unless someone engineers a really big catcher's mitt.

(Sorry, had to throw a little humor in there.)

Seriously though, from what I have read it appears to me, (and this remains no less feasible imho), that their intention is to manipulate said asteroid into some sort of orbit where it may be mined in space.

It is pie in the sky scifi though, I agree.

 

[Antiphon]

It will take a Dutch metallurgical genius to solve this problem. Someone who loves goooooold.

 

[Aidyan]

Why making things complicate? De-orbit slightly a NEO asteroid between the Earth and the Sun so that it takes the path towards Venus (not much thrust needed for that), 'aereobrake' it in Venus' atmosphere such that inserts itself into a synchronous orbit with the Earth + a component for Venus-Earth orbit transferal, and then, once it reaches Earth (at zero orbital velocity) let the thing simply fall freely and splash somewhere in a safe place in the ocean. It would be something like a Tunguska event, but at thousands of miles away from any inhabitated region. Maybe there is a problem with a Tsunami wave, but I think that if the asteroid is not too big, it will not harm. So, why not?