How many M-Type asteroids will Earth (truly) need?

[GeeKay]

I read somewhere that a single 30m wide near-Earth asteroid (2012-DA14) may be worth some $20 trillion dollars in terms of its rare metals content. Meanwhile, the global precious metals market in 2022 was worth $290 billion dollars. That's approximately one hundredth of what DA14 could offer the world. Does this mean then that the mining of one small run-of-the-mill asteroid every few years would be plenty enough to satisfy Earth's needs for the foreseeable future? In other words having an entire offworld mining industry with fleets of asteroid mining outfits plundering the Main belt for its platinum-group metals etc, etc, would be superfluous. . . strictly for the birds, in fact?

Of course, this doesn't factor in surveying costs, those required by heavy plant infrastructure, transportation costs, risk factors and all the other negatives that must otherwise weigh down such an enterprise. Even so, just for the sake of argument - assuming, for instance, fusion-powered spacecraft are running the show by now instead of chemical rockets - would the above thought experiment still hold some water here?

PS. I've posted this question here in the Lounge, given that its topic addresses mineralogy as well as astronomy. Couldn't think where else to put it.

Correction: the ballpark figure quoted above should be one 69th rather than a 100th. My apologies.

[exchemist]

48 minutes ago, GeeKay said:

I read somewhere that a single 30m wide near-Earth asteroid (2012-DA14) may be worth some $20 trillion dollars in terms of its rare metals content. Meanwhile, the global precious metals market in 2022 was worth $290 billion dollars. That's approximately one hundredth of what DA14 could offer the world. Does this mean then that the mining of one small run-of-the-mill asteroid every few years would be plenty enough to satisfy Earth's needs for the foreseeable future? In other words having an entire offworld mining industry with fleets of asteroid mining outfits plundering the Main belt for its platinum-group metals etc, etc, would be superfluous. . . strictly for the birds, in fact?

Of course, this doesn't factor in surveying costs, those required by heavy plant infrastructure, transportation costs, risk factors and all the other negatives that must otherwise weigh down such an enterprise. Even so, just for the sake of argument - assuming, for instance, fusion-powered spacecraft are running the show by now instead of chemical rockets - would the above thought experiment still hold some water here?

PS. I've posted this question here in the Lounge, given that its topic addresses mineralogy as well as astronomy. Couldn't think where else to put it.

Correction: the ballpark figure quoted above should be one 69th rather than a 100th. My apologies.

My understanding of this subject is that the killer, economically, is the huge cost of the change of momentum required to bring extracted minerals back to Earth. These asteroids are on a very different orbit from that of the Earth and momentum change (rocket power) is very expensive, per kilo of payload.

By introducing fusion as a technical mcguffin  to overcome that obstacle, it seems to me one is already making the exercise so far from practical reality as to have little meaning. It then risks turning into one of those "What if the sky were made of concrete?" questions. 

[swansont]

1 hour ago, GeeKay said:

Does this mean then that the mining of one small run-of-the-mill asteroid every few years would be plenty enough to satisfy Earth's needs for the foreseeable future?

Assuming it would be economically feasible to retrieve these metals, I think the question this raises is what would happen if you could suddenly e.g. double the availability of these rare metals. IOW, are there efforts that are supply-constrained?

If the new availability drove prices down, it’s possible that you’d come up with new products that aren’t currently viable owing to cost.

[GeeKay]

1 hour ago, swansont said:

If the new availability drove prices down, it’s possible that you’d come up with new products that aren’t currently viable owing to cost.

Yes, I do wonder sometimes if future developments in nanotechnology and its ilk down here on Earth may dispense with the need to extract precious metals from asteroids in the first place. Even that isn't a given, of course. Few thing are.

[Phi for All]

Mining asteroids makes economic sense only if you leave the metals out there, for use in outer space endeavors. Imagine having tons of metal to work with that you didn't have to bring up from Earth's surface a few kilos at a time at hideous cost.

[Ken Fabian]

@GeeKay the alleged values don't mean much and any mining attempts, if ever, are likely to start small and probably continue to have a lot of very high costs to recover before achieving profitability - and not much affect the market price.

I am amongst the more pessimistic commenters when it comes to space but the resources in asteroids are real - notably Platinum Group Metals mixed in nickel-iron at 10's of parts per million (going by meteorite samples). Even the nickel-iron, raw and unrefined would be considered valuable here on Earth, just for the nickel content. Most things in space have no potential to make money but asteroid minerals are a real "prize" of enormous potential monetary value, so I think the interest will always be there.

 

3 hours ago, exchemist said:

My understanding of this subject is that the killer, economically, is the huge cost of the change of momentum required to bring extracted minerals back to Earth. These asteroids are on a very different orbit from that of the Earth and momentum change (rocket power) is very expensive, per kilo of payload.

 

Yes, the differences in velocities are huge; most of any asteroid mining/refining operation would be making enough fuel/reaction mass for the rockets, which must have exceptional durability and long working life. That is probably the first test that needs to be passed - a rocket that can do a round trip between asteroid and LEO exclusively with "fuel" (and other consumables) produced out of asteroid resources. And do it over and over reliably with absolute minimum of ongoing supply from Earth.

Probably not an M-type. We need to know what those rockets will run on and know if a target asteroid has it. Off the top of my head I would target C-type; going by carbonaceous meteorites they contain the target mineral - nickel-iron with PGM's mixed in - as nodules and grains within a softer carbonaceous material that also contains significant amounts of water.

Can solar electric arc-jets use simple water for reaction mass? H2 + O2 chemical rockets present serious problems, including very large tanks as well as, ultimately, inadequate performance. I think things get harder if any rocket uses requires more exotic fuels, eg the Keck Institute of Space Studies proposal to capture a small asteroid and return in to near Earth space with a solar electric rocket using (if I recall) xenon for reaction mass. Seems very unlikely to find a source of xenon in an asteroid. Hydrazine is used with arc-jets and it seems possible (with water and a source of Nitrogen and equipment) to manufacture it, but water, even if less ideal, presents a simpler challenge to produce and store and use.

[Phi for All]

1 hour ago, Ken Fabian said:

I am amongst the more pessimistic commenters when it comes to space but the resources in asteroids are real - notably Platinum Group Metals mixed in nickel-iron at 10's of parts per million (going by meteorite samples). Even the nickel-iron, raw and unrefined would be considered valuable here on Earth, just for the nickel content. Most things in space have no potential to make money but asteroid minerals are a real "prize" of enormous potential monetary value, so I think the interest will always be there.

Am I missing something? Why would you bring it back here, where it would be really, really expensive nickel-iron, or really, really expensive platinum? I don't have numbers, but terrestrial mining has to be a lot cheaper in almost every aspect. Does not having to pay for mineral rights offset asteroid mining's inherent challenges and their costs, which include identifying and safely bringing the metals back to Earth?

We can keep the metal out in space to build HE3 gathering facilities, something we'll need more of for quantum computing and medical imaging. Not sure how I feel about mining the moon for it, but we don't need much to make a big difference and it's in limited quantities on Earth. It makes more sense to bring this back.

Anything we don't have to send offworld is a resource we get to keep, so I think it makes sense to use what we find out there out THERE as much as possible. At some point, we'll need the metals from asteroids for more projects out there.

[Ken Fabian]

@Phi for All

There may be imaginary "better" uses in space - never any shortage of those - but the only advanced industrialized economy that actually has high demand and high value uses for PGM's and can pay for them, the only one at all - is Earth's. The 'but we can use in space' is sort of right; most of what any proposed asteroid mining operation produces will be for use in space, as essential to being able to deliver resources of high value to Earth - like fuel for the rockets. There is no independent space economy only outposts of Earth's economy.

Sure, if my proposed test case worked it could deliver small amounts of usable asteroid materials eg water, raw nickel-iron, carbonaceous material to NEO there could be demand for them from whatever space stations there are. But what are those space stations doing that makes a profit? I've asked this before but no-one can answer without getting all imaginary. Taxpayer funded space stations that make no profits using such materials may reduce their costs doing that, but the overall totality still relies on Earth subsidy, just a bit less direct.

I don't think any projects in space can achieve self perpetuating growth unless the economics work. What are those activities in orbit that pay their own way with enough left over to support future growth? Subsidy until it works isn't good enough; we need a lot better than that to commit the levels of investment needed.

Without a way to deliver tangible returns to Earth investors it is just dreaming.

[Carrock]

On 3/18/2024 at 4:57 PM, exchemist said:

My understanding of this subject is that the killer, economically, is the huge cost of the change of momentum required to bring extracted minerals back to Earth. These asteroids are on a very different orbit from that of the Earth and momentum change (rocket power) is very expensive, per kilo of payload.

and similar comments...

 

There are a lot of issues with mining asteroids but I don't think this one is significant.

All the delta v you need is sufficient to arrange a first planetary flyby, with slowing and deflection towards another flyby planet, basically the reverse of the many flybys used to get spacecraft from earth to e.g. Jupiter. The minerals would also need entry protection to survive entry at somewhat more than earth's escape velocity.

e.g. a package which would miss a planetary flyby by ten million miles in 10 years' time would only need a delta v around 100mph.

 

[exchemist]

2 hours ago, Carrock said:

and similar comments...

 

There are a lot of issues with mining asteroids but I don't think this one is significant.

All the delta v you need is sufficient to arrange a first planetary flyby, with slowing and deflection towards another flyby planet, basically the reverse of the many flybys used to get spacecraft from earth to e.g. Jupiter. The minerals would also need entry protection to survive entry at somewhat more than earth's escape velocity.

e.g. a package which would miss a planetary flyby by ten million miles in 10 years' time would only need a delta v around 100mph.

 

OK, Interesting. Roughly how many of the requisite planetary alignments would there be per year, or per decade? 

[Carrock]

1 hour ago, exchemist said:

OK, Interesting. Roughly how many of the requisite planetary alignments would there be per year, or per decade? 

For something like the Voyager grand tour, less than one a century...

For a slow journey, all you need is the delta v to get to the first flyby and for course corrections; any asteroid chosen with this in mind would have frequent low delta v options, I'd guess one every year or two. Planetary alignments, possible journeys and required delta v would likely be all worked out long before any mining.

There would be a balance between the cost of rocket fuel etc to minimise journey time and the cost of mined resources unavailable during the journey.

NASA manages these flybys regularly and, it seems, generally chooses to keep time to ultimate target at less than ten years.

 

 

 

[exchemist]

33 minutes ago, Carrock said:

For something like the Voyager grand tour, less than one a century...

For a slow journey, all you need is the delta v to get to the first flyby and for course corrections; any asteroid chosen with this in mind would have frequent low delta v options, I'd guess one every year or two. Planetary alignments, possible journeys and required delta v would likely be all worked out long before any mining.

There would be a balance between the cost of rocket fuel etc to minimise journey time and the cost of mined resources unavailable during the journey.

NASA manages these flybys regularly and, it seems, generally chooses to keep time to ultimate target at less than ten years.

 

 

 

I had an idea it might be something like that. So then the issue would be whether a commercial scale mineral transport operation could function with such long intervals.

[Ken Fabian]

@Carrock

Seems to me we would try for Near Earth Objects (NEO's) by preference. Atiras asteroids are inside Earth's orbit around the sun without crossing it, Atens are inside but do cross it, Apollos are outside and cross it and Amors are outside and don't. They seem likely to have recurring "windows" where lowest delta-v will be possible. I wouldn't start with the Asteroid Belt.

I've suggested C-type (carbonaceous) asteroids by choice, for the water content (for reaction mass) however in general those are more likely to be found further out in the solar system and the Near Earth ones more likely to be S-type (stony). All probably contain nickel-iron but whether they contain carbonaceous or others suitable for extracting fuel/reaction mass is not clear. But the fact that carbonaceous meteorites are common suggest that carbonaceous asteroids could amongst those NEO"s. And if going further afield then there are Mars' moons, which appear to be carbonaceous. Any potential target would deserve some survey sampling.

Edited March 20 by Ken Fabian

[Carrock]

11 hours ago, Ken Fabian said:

@Carrock

Seems to me we would try for Near Earth Objects (NEO's) by preference. Atiras asteroids are inside Earth's orbit around the sun without crossing it, Atens are inside but do cross it, Apollos are outside and cross it and Amors are outside and don't. They seem likely to have recurring "windows" where lowest delta-v will be possible. I wouldn't start with the Asteroid Belt.

I've suggested C-type (carbonaceous) asteroids by choice, for the water content (for reaction mass) however in general those are more likely to be found further out in the solar system and the Near Earth ones more likely to be S-type (stony). All probably contain nickel-iron but whether they contain carbonaceous or others suitable for extracting fuel/reaction mass is not clear. But the fact that carbonaceous meteorites are common suggest that carbonaceous asteroids could amongst those NEO"s. And if going further afield then there are Mars' moons, which appear to be carbonaceous. Any potential target would deserve some survey sampling.

Unless Atiras asteroids cross Venus' orbit no flyby assist is possible. It would be necessary to change the payload's orbit such that its aphelion is at earth's distance from the sun. This would generally require a lot more than 10mph or even 100mph delta v. Similarly for Amor asteroids which don't cross Mars' orbit the payload needs to be decelerated for an earth distance perihelion. There is only one convenient planet to aim for and if the asteroid's orbital period is similar to earth's you may have to wait years for a lowish energy/fast transit window.

Quote

From Wikipedia

The Aten asteroid with the smallest known perihelion is also the one with the highest known eccentricity: (137924) 2000 BD19 has an orbit with an eccentricity of 0.895, which takes it from a perihelion of 0.092 AU, well within Mercury's orbit, to an aphelion of 1.66 AU, which is greater than the semi-major axis of Mars (1.53 AU).

That Aten asteroid does look quite promising...

Within reason you want an asteroid from which as many planets as possible can be reached occasionally by a low delta v burn. I suspect, without (years of) calculation that asteroids from which Mars, Jupiter and Saturn can sometimes be reached with low delta v would be good. Several asteroids in different orbits could effectively spread out the windows.

 

The point of planetary flyby is to donate to or abstract from the flyby planet's velocity and momentum with a very small initial delta v rather than obtain it all from burning fuel.

You would only need a tiny amount of fuel (tons of payload per gallon of fuel) which I expect would be present in adequate quantities in most asteroids.

b.t.w. I'm still very dubious about asteroid mining....