The Feasibility of Capturing NEOs and Bringing Them To the Earth-Moon System and Then Mining Them For Profit

[Yarn]

In another forum, I was engaged in a sizable conversation with an aerodynamics student specializing in propulsion about the feasibility of capturing NEOs with vast amounts of mineral wealth into the Earth-Moon System and then mining them for profit through import of precious metals to Earth's surface so as to establish large amounts of self-sustaining space infrastructure that would bring us substantially closer to being able to construct and maintain space colonies.

 

It has come to my attention that some nickel-iron asteroids, such as 1986 DA, possess in excess of $6 trillion worth of Platinum embedded in, in this instance, dimensions of a 2km rock composed primarily of other heavy elements. Platinum, once refined, is worth more than $21,000 a pound. Although it is possible fusable elements like helium-3 could someday rake in more money per mass if fusion technology ever took off, as of today platinum is probably the most instrinsically valuable material we could hope to find in space and the one with the best chance of justifying capital investments towards its acquisition from therein.

 

It is thought in turn that several of the major mining sites from which we extract this resource on Earth gained their high concentration of it from long ago nickel-iron asteroid impacts. A problem with these impacts is that their intense violence ensured that a large portion of the mineral wealth contained in the colliding asteroids became diffused by them, thereby making mining less attractive than if the asteroids had magically landed intact and compact on the Earth's surface. The Moon of course has its own challenges for extraction, but it is thought asteroid impacts on the moon would've caused less diffusion because the moons lower gravity ensures a less violent collision. Also, since the moon doesn't geologically resurface, the minerals would not have the same tendency to sink over the course of many millions of years like heavy minerals do on the Earth. Mining the moon may be the most economically feasible method of mining space at present, and indeed one of the three main competitors for the lunar X-Prize has mining platinum group metals off the moon as one of its longterm objectives. However, one thing a captured NEO would have that the moon would not have is an extremely low extremely cheap escape velocity. With NEOs, for instance, we could propel mining operations with VASMIR ion engines (200 kw thrust of 5 newtons) alone. The moon requires more thrust to escape than any ion engine could provide, so it would require a chemical rocket of some sort. It has water (i.e. potential sources of H2 and O2) in polar craters that could be used to synthesize rocket fuel, but anyways, this thread is to be about NEOs.

 

There are several challenges then that we face towards mining NEOs. First we have to get them here, second we have to adjust their velocity finely enough to get them into orbit (probably lunar orbit for safety reasons), and third we would have to come up with an economically feasible way to mine them.

 

I have some things to say about how we might do these things, but I don't have sufficient background to have confidence in them.

 

So i'll layout a couple questions, as well as invite everyone to give their own ideas and skepticism regarding the feasibility and potential methods for fulfilling these 3 elements.

 

Is it feasible, within a time frame of 50 or so years, to influence the course of a 10^10 Kg sized NEO (which could be worth $60 billion supposing same ratio of mass to platinum as 1986 DA) into an orbit with the moon via use of ion engines?

 

We did calculations in the other forum to the effect that nuclear explosions are powerful enough that they can easily and extremely manipulate the velocity and trajectory of an object of that size, but would the object be able to survive nuclear explosions intact enough to remain useful?

Edited July 24, 2011 by Yarn

[InigoMontoya]

Have you taken into account that much of Platinum's value is due to scarcity? The point being that if you start dumping massive amounts of Platinum on the market (required if you want to make any money), the value will plummet. It's an economic Catch-22. If you want to make money, you have to sell it. But if you sell it, it no longer commands a high price.

 

Beyond that.... No, it is not feasible. Even if the engineering could be done, look at the politics. What do you think's going to happen if you tell the world, "Hey, we want to bring this asteroid home with us. Everything should be cool, but if we screw up a very large percentage of the Earth's populace could die. Oh, and our motive is money."

 

Yeah, I don't see that one going over so well.

[Yarn]

Have you taken into account that much of Platinum's value is due to scarcity? The point being that if you start dumping massive amounts of Platinum on the market (required if you want to make any money), the value will plummet. It's an economic Catch-22. If you want to make money, you have to sell it. But if you sell it, it no longer commands a high price.

 

Beyond that.... No, it is not feasible. Even if the engineering could be done, look at the politics. What do you think's going to happen if you tell the world, "Hey, we want to bring this asteroid home with us. Everything should be cool, but if we screw up a very large percentage of the Earth's populace could die. Oh, and our motive is money."

 

Yeah, I don't see that one going over so well.

 

Regarding the price of platinum, the vast majority of all platinum is used in a diverse assortment of industrial applications. Most of it, by a small majority, is used in making engines burn gas more completely. So it is as scalable as these applications are, and initially platinum from space will, as far as jewelry is concerned, be more valuable than that from Earth. No doubt the price will go down, but if space supply is the limiting factor on total supply then it could not go down far enough to make existing levels of space extraction unprofitable.

 

Regarding the safety issues, that would be why you would put it in lunar orbit rather than in Earth orbit. Trajectory calculations are reliable things, meaning so long as we lined up the object's trajectory well in advance there would be no risk of it colliding with the Earth when you have a practical margin of error of more than 380,000 km.

Edited July 24, 2011 by Yarn

[InigoMontoya]

Regarding the price of platinum, the vast majority of all platinum is used in a diverse assortment of industrial applications. Most of it, by a small majority, is used in making engines burn gas more completely. So it is as scalable as these applications are, and initially platinum from space will, as far as jewelry is concerned, be more valuable than that from Earth. No doubt the price will go down, but if space supply is the limiting factor on total supply then it could not go down far enough to make existing levels of space extraction unprofitable.

Agree to disagree.

 

Regarding the safety issues, that would be why you would put it in lunar orbit rather than in Earth orbit. Trajectory calculations are reliable things, meaning so long as we lined up the object's trajectory well in advance there would be no risk of it colliding with the Earth when you have a practical margin of error of more than 380,000 km.

True statement. Now explain to me how you're going to control the trajectory so precisely with nukes. You're talking about playing a game that has never been played before that has global implications if you fail at it. You may say it's easy; that anybody could do it. Funny thing... Space travel is supposed to be the same way, and yet NASA has killed off 14 astronauts in my lifetime alone. Now you want to play a similar game with unproven technologies involving massive unknowns and with the whole globe at risk if you screw it up? And you want to do this just so you can make a buck? Good luck finding the political will. And if you DON'T think that'll be a difficult task; you truly are naive.

Edited July 24, 2011 by InigoMontoya

[Yarn]

Agree to disagree.

 

 

True statement. Now explain to me how you're going to control the trajectory so precisely with nukes. You're talking about playing a game that has never been played before that has global implications if you fail at it. You may say it's easy; that anybody could do it. Funny thing... Space travel is supposed to be the same way, and yet NASA has killed off 14 astronauts in my lifetime alone. Now you want to play a similar game with unproven technologies involving massive unknowns and with the whole globe at risk if you screw it up? And you want to do this just so you can make a buck? Good luck finding the political will. And if you DON'T think that'll be a difficult task; you truly are naive.

 

The nukes are for gross adjustment, VASIMR ion engines could be used for fine adjustment. Once the trajectory of the object is set into the ball park of the Earth-Moon system, over the course of years, if I am not mistaken, VASIMRs could adjust the trajectory to wherever we wanted it therein.

 

A nuclear-powered VASIMR ion engine, though one has yet to be tested because VASIMR's are a very new technology and so far we are still working on and succeeding at weaker nonnuclear prototypes for near Earth use, could supposedly get humans to Mars in 39 days. That is a distance of more than 54 million km in a duration of 5 and a half weeks. However, NEOs are much more massive than spaceships. Still, for fine adjustment, we are looking at much smaller distances over far longer periods of time.

 

Several carefully placed multimegaton nuclear warheads could also be placed on the object to vaporize it in the event we messed up and it intersected with Earth. An asteroid of of 10^10 kg, though perhaps containing tens of billions in mineral wealth, would only be around a 100 meters across. Nuclear adjustment is the most sketchy part of the capture scheme because the nukes used would have to be weak enough to not obliterate the object, aka somewhere in the kiloton range if even that would work. This would mean we would to have use quite a few of them, perhaps a prohibitive number.

 

I am not sure whether VASIMR engines by themselves, perhaps by manipulating interaction with gravitational effects, could capture an object within 50 years. If they could, they would probably be the better choice.

Edited July 24, 2011 by Yarn

[Ophiolite]

Inigo introduced a point that would need to be considered: the drop in value of the platinum consequent upon its massive increase in availability. He has naively failed to notice that de Beers successfully created an artificial demand for a mid range value product then sustained the artificially high price for decades by controlling supply.

 

Two other points to be considered relating to the economics:

Many more materials other than platinum would be available from the NEO. Not all of them would be worth the trouble of extraction and return to the Earth, but some of them certainly would.

The ultimate decision on the economic value of the project would depend upon detailed estimates of platinum (and other) demand; consequent pricing; cost of implementing the project; the timescale of the project. There is insufficient data on each of these elements at present to say whether or not such a project would be viable.

 

Technically I have one major concern. We know that stony asteroids are probably not much more than rubble piles. We suspect the irons are more cohesive, but at this point I don't think the matter is settled. If they also lack cohesion the use of nuclear devices to divert them would, as well, disrupt them. Robotic and manned visits to NEOs could settle this matter and would be an essential first step for the project.

 

Politically this is not a challenging task if the issue of NEO cohesiveness has been dealt with. The loss of astronauts and cosmonauts in the space program has not halted the program. Over four hundred individuals have paid a deposit to make a sub-orbital flight on Virgin Galactic. Humans, despite recent tendency to wimpishness, are risk takers. (People also like to make money. If you tell everyone the price of their catalytic convertor is going to come down, they will love you.) In short, the political side can be handled.

[Realitycheck]

As far as I can tell (which isn't saying much), VASIMIR's employ a relatively substantial amount of thrust and would be kind of overkill being used as a tug. Wouldn't a regular ion engine suffice? Maybe there isn't necessarily anything wrong with too much thrust, but I'm just thinking about how tugboats always move real slow.

 

Err, I just reread that you stated that the moon would require VASIMIR's for moving. What does the moon have to do with it? Probably just a typo.

 

Maybe when you factor in the distance that these asteroids are from earth, then maybe mining them where they are is more efficient. I mean, you're either going to be mining them where they are or mining them in orbit, seems like kind of a waste of energy. Just a thought.

Edited July 24, 2011 by Realitycheck

[Ophiolite]

Err, I just reread that you stated that the moon would require VASIMIR's for moving. What does the moon have to do with it? Probably just a typo.

If we are reading the same sentence, then he is referring to placing the NEOs in lunar orbit to minimise the concerns over accidental Earth impact.

[Yarn]

The reason why we would need VASMRs, as opposed to traditional ion engines, is that NEOs are incredibly heavy. The $60 billion NEO I mentioned would weigh around 10 million metric tons. A traditional ion engine has a thrust measured in milinewtons. Even with VASMR, with its thrust being measured in whole newtons, the rate trajectory change would be small. Movie is about to start, gtg, more later

[InigoMontoya]

Inigo introduced a point that would need to be considered: the drop in value of the platinum consequent upon its massive increase in availability. He has naively failed to notice that de Beers successfully created an artificial demand for a mid range value product then sustained the artificially high price for decades by controlling supply.

A fair, but I believe irrelevant point. If, by some miracle, somebody managed to make capture such an asteroid and actually make money doing it... Somebody else could simply capture another one. And their job would be easier as they'd be able to leverage the lessons learned by the first group to make it work. De Beers can pull some stunts because it's difficult to create a diamond mine out of thin air... But in this case, somebody in effect could.

 

Many more materials other than platinum would be available from the NEO. Not all of them would be worth the trouble of extraction and return to the Earth, but some of them certainly would.

Now THAT, is an excellent point.

 

Politically this is not a challenging task if the issue of NEO cohesiveness has been dealt with. The loss of astronauts and cosmonauts in the space program has not halted the program. Over four hundred individuals have paid a deposit to make a sub-orbital flight on Virgin Galactic. Humans, despite recent tendency to wimpishness, are risk takers. (People also like to make money. If you tell everyone the price of their catalytic convertor is going to come down, they will love you.) In short, the political side can be handled.

And in every case you mention, the risk is 100% assumed by volunteers. This would not be the case for the scenario in question. Agree to disagree on the political side.

 

 

 

 

edit: Finally decided to run some numbers to address the engineering aspects of it

 

According to a quick google, VASMRs run at an Isp of about 5400 s.

 

Lets assume that we need a dV of 1 km/s. That's pretty damned low, really, but we'll assume we've got a juicy asteroid somewhere really, really close.

 

dV = go * Isp * ln(MR) => 1000 = 9.81 * 5400 * ln(MR)

 

=> ln(MR) = .019

 

=> MR = 1.019

 

MR = (Minert + Mreaction) / Minert

 

Minert = 10^10 kg

 

=> Mreaction = 191e6 kg = 191,000 metric tons.

 

 

Wowzers. That's a whole crapload of reaction mass. By comparison, a fully loaded aircraft carrier weighs in at approximately 106,000 metric tons.

 

So basically, you'll need to get approximately *TWO* Nimitiz class aircraft carriers to your asteroid to bring it back. Note: That's not what you have to leave Earth with, that's what you have to arrive at your asteroid with.

 

Feasible in 50 years?

 

Not even.

Edited July 25, 2011 by InigoMontoya

[CaptainPanic]

The problem is very simple: you can only spend so much money to make a particular metal.

Or, if we approach it from the other side: every kilogram of asteriod that is brought into orbit costs a certain amount of money. Most of that asteriod isn't even worth it to be put into orbit, let alone to be brought down to the surface.

 

For the large majority of metals, it's just not worth the fuel to slow down an asteroid into orbit around either the Earth or the Moon. Tin is one of the more expensive metals and that goes for just 28 $/kg.

 

I'm not gonna do any calculations today, but I think you might be better off to mine the precious metals on the moving asteroid (not in orbit), and attach your nukes and ion thrusters only to the product (the really expensive metals) to send that into earth orbit. That way, you only have to accelerate/decellerate a tiny fraction of the total mass.

[Airbrush]

Realitycheck: "...mining them where they are is more efficient. I mean, you're either going to be mining them where they are or mining them in orbit, seems like kind of a waste of energy...."

 

Captain Panic: "...better off to mine the precious metals on the moving asteroid (not in orbit), and attach your nukes and ion thrusters only to the product...."

 

I agree. Leave the asteroids where they are, and mine them where they are. Only expend the energy necessary to ship the valuable materials to Earth. What good is it to ship a lot of useless rocks and debris here?

 

First find the rich deposits by robotic probes. Then either with the help of humans, or totally automated, establish mining equipment on the rock. Ideally, you may even manufacture some of your equipment using the materials on the rock.

Edited July 25, 2011 by Airbrush

[Yarn]

Gold is worth nearly as much as Platinum and therefore could also be worth extracting. However, all the other present metals aren't worth enough to justify extraction, and they make up the vast majority of the NEO.

 

It would take a longtime to get to and from a typical NEO. You would frequently be dealing with trips of tens of millions of km.