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Thread: Asteroid mining

  1. #181
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    Quote Originally Posted by Noclevername View Post
    ....

    So, could PG metals industrial value justify the return on investment if mined in space but brought to Earth for processing?
    Zubrin is pretty bullish about it in his ‘asteroids for fun and profit’ chapter in the Case For Space.

    He quotes a book by Prof Lewis (Uni of Arizona) which suggests a fairly typical 1 km S-type asteroid of 2bn tonnes could contain 200 m t of iron, 30m t of high quality nickel, 1.5 m t of cobalt and 7,500 t of platinum group metals. It would also contain not insignificant quantities of carbon and oxygen.

    This sounds a useful ‘reference‘ asteroid for analysing the costs and benefits.

    He then explores the basic economics.

    The PGM alone are worth around $300bn. But this is only 0.000375 % of the total bulk. So will need refining in situ. He suggests that the Nickel, iron, oxygen and carbon would only be of use in situ. Only the PGM (0.5%) and cobalt (99.5%j would be worth refining and bringing back to Earth.

  2. #182
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    Quote Originally Posted by Van Rijn View Post
    My understanding is that they are still a small percentage of the source material and delta-v is the biggest cost issue after cost of developing hardware, so you want to mine and process on site...
    The delta-v’s impact on fuel needed does seem to be a key driver of space costs generally, with the lower gravity of asteroids making them more accessible for less fuel than say Mars or the Moon...

    The Astrobank database lists Asteroid’s by delta-v with estimates of potential value and profit. Would be useful to look into the assumptions behind those estimates which look rather suspiciously precise.

    https://www.asterank.com/

    Interesting to see the top 5 by Delta- V [Delta-V]
    - Ryugu. [4.7]. Type - Cg. Apollo. Visited by Hayabusa in a sample return mission due back soon.
    - 1989 ML [4.9]. Type - X. Amor. Considered for visit but didn’t happen.
    - Nereus [5.0]. Type-Xe. Apollo. Considered for visit but didn’t happen. Potentially Hazardous Asteroid. Next close approach Dec 2021.
    - Bennu [5.1]? Type-B. Apollo. Osiris-REx there now, due to take a sample On 20th October.

    Apparently Ryugu, valued at $82.76 billion, will deliver the biggest profit of the top five at $30.08 billion - so why don’t we choose that one?!

  3. #183
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    Quote Originally Posted by DavidLondon View Post
    The delta-v’s impact on fuel needed does seem to be a key driver of space costs generally, with the lower gravity of asteroids making them more accessible for less fuel than say Mars or the Moon...

    The Astrobank database lists Asteroid’s by delta-v with estimates of potential value and profit. Would be useful to look into the assumptions behind those estimates which look rather suspiciously precise.

    https://www.asterank.com/

    Interesting to see the top 5 by Delta- V [Delta-V]
    - Ryugu. [4.7]. Type - Cg. Apollo. Visited by Hayabusa in a sample return mission due back soon.
    - 1989 ML [4.9]. Type - X. Amor. Considered for visit but didn’t happen.
    - Nereus [5.0]. Type-Xe. Apollo. Considered for visit but didn’t happen. Potentially Hazardous Asteroid. Next close approach Dec 2021.
    - Bennu [5.1]? Type-B. Apollo. Osiris-REx there now, due to take a sample On 20th October.

    Apparently Ryugu, valued at $82.76 billion, will deliver the biggest profit of the top five at $30.08 billion - so why don’t we choose that one?!
    Well, if you think the 26 months between launch windows to Mars is inconvenient, for Ryugu it's about twice as long. 40 months for 1989 ML, back down to 26 for 4660 Nereus, and 72 months for Bennu.

  4. #184
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    Quote Originally Posted by DavidLondon View Post
    The delta-v’s impact on fuel needed does seem to be a key driver of space costs generally, with the lower gravity of asteroids making them more accessible for less fuel than say Mars or the Moon...
    Well, it can be a driver, but it gets complicated. One of my annoyances is that I’ve seen few real attempts at trying to conceptualize an economic plan to mine the moon or asteroids. Maybe somebody is doing it behind closed doors, or maybe it is just considered too speculative at this point. Maybe it is a bit of both.

    Delta-v issues are at least partly affected by the transportation method used. The economics of chemical rockets fueled on Earth will be severe. If the fuel is derived from lunar or asteroid sources, it could be better. For NEO asteroids you might be able to avoid much of the issue using solar sails, although they would be subject to micrometeoroid damage over time. There are potential methods of launching mass off the moon without using rockets. If you do most or all of the processing at the site, you can minimize the issue if you only transport high value material.

    Mining and processing methods are also going to be different from methods used on Earth. For NEOs there is constant available sunlight. A lot of processing might amount to using a large parabolic reflector to melt material and spin it in a high speed centrifuge to separate it. But it will need to be mined first. If the asteroid is a rubble pile, that might not be too hard, but it would be a different story if it is solid. The asteroid will also probably need to be bagged, or dust will go everywhere.

    Getting it to the earth’s surface could also be an issue. If there isn’t a lot of mass, return craft like Starship could do it. On the other hand, I’ve thought about making crude return objects shaped for controlled entry but made with a regolith heat shield surrounding the valuable metal inside, that would be directed to land in lonely section of ocean.


    The Astrobank database lists Asteroid’s by delta-v with estimates of potential value and profit. Would be useful to look into the assumptions behind those estimates which look rather suspiciously precise.

    https://www.asterank.com/
    Interesting site, but yes, they need some large error bars on that. You can make some guesses on composition based on the asteroid’s spectral results and comparing it to meteorites, but that only tells you so much. You also need to make a mass estimate and that can be well off actual mass. And that doesn’t cover actual mining and transport costs. After all, if mining and transport costs were no object, any random chunk of land on Earth would be a valuable mining spot.

    Apparently Ryugu, valued at $82.76 billion, will deliver the biggest profit of the top five at $30.08 billion - so why don’t we choose that one?!
    At least it has been visited, so we have and will be getting more information on it, but it will take a properly developed mining plan at least before that can be considered.

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  5. #185
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    Quote Originally Posted by Van Rijn View Post
    Delta-v issues are at least partly affected by the transportation method used. The economics of chemical rockets fueled on Earth will be severe. If the fuel is derived from lunar or asteroid sources, it could be better. For NEO asteroids you might be able to avoid much of the issue using solar sails, although they would be subject to micrometeoroid damage over time. There are potential methods of launching mass off the moon without using rockets. If you do most or all of the processing at the site, you can minimize the issue if you only transport high value material.
    Building a working Lunar mass driver would be a darn sight harder than mining an asteroid, I think!

    Quote Originally Posted by Van Rijn View Post
    Mining and processing methods are also going to be different from methods used on Earth. For NEOs there is constant available sunlight. A lot of processing might amount to using a large parabolic reflector to melt material and spin it in a high speed centrifuge to separate it. But it will need to be mined first. If the asteroid is a rubble pile, that might not be too hard, but it would be a different story if it is solid. The asteroid will also probably need to be bagged, or dust will go everywhere.
    Easier to mine, but prospecting a rubble pile would also be more challenging than a solid body. The RP could be a random non-homogenous conglomeration, who knows what might be under the surface?
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  6. #186
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    Quote Originally Posted by Noclevername View Post
    Building a working Lunar mass driver would be a darn sight harder than mining an asteroid, I think!
    Perhaps or perhaps not. For one, there is a concept (I don’t recall the name) where you put the mass to be launched at the end of an arm that is spun up until it reaches orbital or escape velocity and then the mass is released. It might be a more practical option, but like the mass driver gets mass up just using solar or nuclear derived energy.

    And then there is the question, just how small can you make a mass driver that is still useful? The O’Neill mass driver concept is a monster intended to launch enough mass for huge space habitats, but what if you have something that launches grams at a time, but operates quick enough that the total mass launched still amounts to something? Instead of having one or two monsters, you might end up with dozens of mini launchers as demand increases.

    Easier to mine, but prospecting a rubble pile would also be more challenging than a solid body. The RP could be a random non-homogenous conglomeration, who knows what might be under the surface?
    I don’t know if it is more challenging. My understanding is that most small asteroids are probably not very differentiated. You aren’t likely to find rich ore in part of it.

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  7. #187
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    Quote Originally Posted by Van Rijn View Post
    ...One of my annoyances is that I’ve seen few real attempts at trying to conceptualize an economic plan to mine the moon or asteroids. Maybe somebody is doing it behind closed doors, or maybe it is just considered too speculative at this point. Maybe it is a bit of both.
    It is annoying trying to get hard evidence. Building a robust evidence base for estimating costs and benefits, including risks and assumptions, for projects is the biggest challenge for asteroid mining project development.
    Moving from an outline business case - which eg may have an options long list considering a load of potential target asteroids, refining method options, transport options etc - to a more detailed business case which identifies only a few Shortlisted options for more detailed analysis can be a lot of effort.

    And at the moment I sense that there are significant uncertainties (including radical uncertainties or ‘unknown Unknowns’) so even developing a robust outline case would be difficult. Which is why I think the focus right now is more on strategic context and fit analysis (ie for business case).
    Also the kind of business case needed in bids for public resources are likely to have different priorities than purely commercial business cases on important issues such as the discount rate assumed. So a range of differently inputs will be needed.

    If a business has invested commercial funds in developing an outline business case for a specific project then its entirely understandable for them to be reluctant to make all key details widely available for potential competitors to ‘free ride’ on the information assembled. At the same time, while some inputs will be commercially sensitive, a lot of the key inputs will probably be widely assumed if not publicly available and so can help us all get a sense of some of the key challenges facing a project.

    Robert Z sketches out a very rough but interesting analysis of costs and benefits for the reference asteroid from his book as I outlined in my post #181. He actually suggests further refinement of the material to deliver a 10% PGM, 90% cobalt split. He then concludes that, provided the right technology is put to work, the business case “could well be there’.

    He even concludes that, until asteroid supply sharply reduces the cost of PGMs On earth, the returns for the first miners could well be spectacular and sky-high. Even when the price falls - which as he rightly says would deliver huge benefits on earth from cheaper products such as fuel cells - there would still be normal profits to be made from asteroid mining while costs would fall as more experience is gained.

    So let’s choose an asteroid from the Asterank database and go for the sky-high bounty of first mover advantage without delay!

    To be fair on Robert Z, I think his book is a great presentation of a kind of vision case for investment in space. It is an inspiring book with lots of practical solutions. But I sense that Robert’s ‘almost there’ business case is just a bit vulnerable to what, in business case language, is called ‘optimism bias’.

    It will need the strength of much more substantial business case analysis if we are to persuade potential public, commercial or social investors to provide the finance.

  8. #188
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    Apols but my list of Asterank top 5 by delta-v omitted number 5.

    It is:
    - Didymos. Type Xk. Apollo and Amor. PHA. [Delta-v 5.2].
    NASA’s DART Mission is due to set off to Didymos (and it’s small binary companion Dimorphous otherwise known as Didymoon!) In July 2021 which will aim to impact the Moon with an ESA project proposed a few years later to analyse the results from the impact.

    Worth also mentioning no 7 on the Asterank list Anteros. It has a potential profit of over $1bn US$!

    The following assumptions are used in the value and profit estimates...

    Overview of estimates
    Value estimates are based on the mass of a given asteroid and its spectral type. Asteroid spectra is used to infer composition, which, in conjunction with current market prices, determine potential value.

    Accessibility estimates are based primarily on delta-v, but it also incorporate orbital characteristics such as perihelion, aphelion, eccentricity, and period. The formula is biased toward low delta-v with orbits that maintain a generally consistent distance from the sun (ie., no objects that swing far into the belt).

    Profit and ROI calculations are a combination of accessibility and value. The formula strikes a balance between high value and high distance and energy expenditure. Mining costs are factored in as a flat percentage of potential value”.

  9. #189
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    Bennu and asteroid mining...

    https://www.cnbc.com/2020/10/16/nasa...steroid-m.html

    Some interesting comments on the significance of the Osiris-Rex mission for asteroid mining.
    While Vogel thinks “the business case doesn’t quite close on” asteroid mining currently, he noted that there are several aspects of the mission that could be used in the future – a fact Lauretta further emphasized.

    “We do look at these near Earth asteroids as economic resources potentially,” Lauretta said. “It’s an expensive operation, but any mining operation is expensive to get up and running. And these do represent natural resources that are accessible in the solar system.

    “in some ways we’re the prospector,” Lauretta added. “We’re out there checking the composition of these materials and we’re bringing it back. It’s like the old geologists that was poking around in the mountains, bringing back the spec samples to the lab, see if it’s worth mining or not.””
    For more on Osiris-Rex see comments in the separate thread at:
    https://forum.cosmoquest.org/showthr...-astroid-Bennu
    Last edited by DavidLondon; 2020-Oct-24 at 10:05 AM.

  10. #190
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    Speaking of asteroid mining, I was a bit irritated by this article:

    https://www.yahoo.com/news/telescope...173059231.html

    Telescope gives closer look at asteroid worth $10,000 quadrillion
    It starts out by saying the asteroid is worth "more than the entire world economy." That's if you could get it on earth, and actually sell those things. But it also bothers me that it's so out of context. I don't know how much the sun is worth, but if hydrogen is about a dollar per kilogram, then the sun is worth a lot of money, but nobody ever mentions that. Not that I'd want to be the one to have to go fetch it.
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  11. #191
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    Thanks for the interesting article. 16 Psyche is certainly an interesting object and worth a discussion. It’s the largest M-type metallic asteroid known and the NASA mission to it mentioned in the article should discover a lot about metallic asteroids when it arrives in 2026.

    Quote Originally Posted by Jens View Post
    Speaking of asteroid mining, I was a bit irritated by this article:

    https://www.yahoo.com/news/telescope...173059231.html

    It starts out by saying the asteroid is worth "more than the entire world economy..."
    I agree that it is not especially helpful to focus on its potential value on earth. But at least they say that the forthcoming mission is not interested in bringing anything back.

    The following Universe Today article is also worth a look, but it also is a bit obsessed with its so-called value in the headlines.

    https://www.universetoday.com/142719...ecious-metals/

    So how likely is it to be a shortlist target for early asteroid mining? My hunch is that it’s more of scientific interest and one for later asteroid mining once the nearer asteroids such as those at the top of the Asterank database mentioned in above Posts (#182, #187, #188) like Ryugu or Bennu have been mined.

    The database suggests Psyche has a value of $28bn and potential profit of $1.78bn which is quite a lot less than the top targets, but doesn’t list its delta-v. So it’s not clear how much it would cost to reach it. You would also need to get refining infrastructure out to the main asteroid belt.

    Typical metallic asteroids are mainly iron and nickel - these are not really materials which are cost effective to bring back to earth. But typically they also contain metals like cobalt and very small but not insignificant quantities of platinum group metals which could be worth refining and bringing back to earth - it’s just that there are plenty of these in asteroids which are much nearer. Gold is also mentioned as being present on Psyche.

    My hunch is that by the time we seriously consider mining Psyche it will not be for many decades - even over a century - and at a time when we already have experience of NEO asteroid mining and are moving out beyond Mars and populating the asteroid belt.
    But others may be more optimistic?

  12. #192
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    Ice aside, Mars has surface deposits of high-grade ores (the sort of deposits that were largely exhausted on Earth centuries ago) that could be commercially mined and smelted into usable products with relatively little machinery. You could potentially see commercial mining of metals on Mars in a couple decades, with SpaceX's Mars operations as the main customer.

    Asteroid mining will be much more difficult, will involve longer transit times and a lot more R&D into how to effectively mine and process materials, but I expect mining on Mars will clear a psychological barrier and jump-start interest in mining asteroids as well. I wouldn't be surprised to see prospectors and sample collectors at Psyche at around the same time (as one of the biggest targets, if not as a near-term candidate for active mining), and mining R&D operations setting up on Phobos and Deimos.

  13. #193
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    Quote Originally Posted by cjameshuff View Post
    Ice aside, Mars has surface deposits of high-grade ores (the sort of deposits that were largely exhausted on Earth centuries ago) that could be commercially mined and smelted into usable products with relatively little machinery. You could potentially see commercial mining of metals on Mars in a couple decades, with SpaceX's Mars operations as the main customer.

    Asteroid mining will be much more difficult, will involve longer transit times and a lot more R&D into how to effectively mine and process materials, but I expect mining on Mars will clear a psychological barrier and jump-start interest in mining asteroids as well. I wouldn't be surprised to see prospectors and sample collectors at Psyche at around the same time (as one of the biggest targets, if not as a near-term candidate for active mining), and mining R&D operations setting up on Phobos and Deimos.
    If earth (before it was exploited) and Mars has surface deposits of high-grade ores, wont the moon have them too?

  14. #194
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    Quote Originally Posted by selvaarchi View Post
    If earth (before it was exploited) and Mars has surface deposits of high-grade ores, wont the moon have them too?
    Why would you expect that? Earth and Mars have atmospheres and hydrospheres, and surfaces that have been subject to weathering, wind and running water, a long history of volcanic activity melting, crystallizing, and re-melting rocks, Mars even has signs of tectonic activity like Earth's.

    The moon has the basalt it formed when it solidified, the exposed portion of which has been getting pulverized and mixed by impacts over the subsequent billions of years. If you're not after aluminum, iron, titanium, or magnesium, you're going to have to process huge masses of rock that probably wouldn't even be considered an ore on Earth or Mars to get it. It's not even going to be an especially good ore of those elements, most of what you handle is going to be silicon and oxygen. There's probably bauxite or a comparable clay mineral somewhere on Mars, there's certainly hematite and one of our rovers got stuck in a deposit of iron sulfate, there's almost certainly similar deposits of magnesium salts. The moon has basalts containing a couple tens of percent of ilmenite, there's likely deposits of rutile sands somewhere on Mars.

  15. #195
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    Quote Originally Posted by selvaarchi View Post
    If earth (before it was exploited) and Mars has surface deposits of high-grade ores, wont the moon have them too?
    I’m not a geologist, but a few thoughts on this:

    The moon may well have some kinds of high grade ore, but its geology has to be significantly different from that of Earth and Mars. The moon is thought to have been the result of a Mars sized planetesimal hitting Earth, with a lot of the denser material staying with Earth. Second, the Moon would have lost most of any water it did have fairly quickly. Water is very important in Earth and Mars geological processes and differentiation, so it is likely Mars has more usefully enriched types of ore than the Moon. Third, the Moon would have cooled down much more quickly than Earth or Mars, so would have had less time for geological processes to occur.

    Mars is smaller than Earth and also had less time for a highly active geology with water, but appears to be more like Earth geologically in many ways than the Moon. Mars also has had more atmosphere, especially in the past. Early in human history, iron nickel meteorites could be found here and there and were easy to use for making tools. It helped that smaller ones would be slowed down by the atmosphere before impacting. The Moon wouldn’t have had that.

    That said, the moon might have something like Sudbury basin, a major mining site. It is thought it was caused by an ancient asteroid or comet impact.

    Of course, Mars has a lot more volatiles than the Moon. The atmosphere would make it harder to build non-rocket mass launching systems but it would be easier to produce fuel for rockets, and to provide volatiles for inhabitants. Mars has a deeper gravity well than the Moon, but it still wouldn’t be very hard to fly single stage to orbit rockets.

    Phobos and Deimos are interesting. They have a pretty low delta-v requirement to reach them from Earth, and if they are mined, could be a huge boon to orbital development around Mars. But we don’t know that much about what they are made of. With luck, there may be water containing minerals under the surface, but the surface seems fairly dry.

    If Mars is developed, I suspect the activity in orbit will be as important as the activity on the surface for a long time.

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  16. #196
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    Quote Originally Posted by Van Rijn View Post
    I’m not a geologist, but a few thoughts on this:

    The moon may well have some kinds of high grade ore, but its geology has to be significantly different from that of Earth and Mars. The moon is thought to have been the result of a Mars sized planetesimal hitting Earth, with a lot of the denser material staying with Earth. Second, the Moon would have lost most of any water it did have fairly quickly. Water is very important in Earth and Mars geological processes and differentiation, so it is likely Mars has more usefully enriched types of ore than the Moon. Third, the Moon would have cooled down much more quickly than Earth or Mars, so would have had less time for geological processes to occur.

    Mars is smaller than Earth and also had less time for a highly active geology with water, but appears to be more like Earth geologically in many ways than the Moon. Mars also has had more atmosphere, especially in the past. Early in human history, iron nickel meteorites could be found here and there and were easy to use for making tools. It helped that smaller ones would be slowed down by the atmosphere before impacting. The Moon wouldn’t have had that.

    That said, the moon might have something like Sudbury basin, a major mining site. It is thought it was caused by an ancient asteroid or comet impact.

    Of course, Mars has a lot more volatiles than the Moon. The atmosphere would make it harder to build non-rocket mass launching systems but it would be easier to produce fuel for rockets, and to provide volatiles for inhabitants. Mars has a deeper gravity well than the Moon, but it still wouldn’t be very hard to fly single stage to orbit rockets.

    Phobos and Deimos are interesting. They have a pretty low delta-v requirement to reach them from Earth, and if they are mined, could be a huge boon to orbital development around Mars. But we don’t know that much about what they are made of. With luck, there may be water containing minerals under the surface, but the surface seems fairly dry.

    If Mars is developed, I suspect the activity in orbit will be as important as the activity on the surface for a long time.
    The mineral content of the Sudbury basin came from Earth, the impactor is just thought to have triggered volcanism that brought those minerals to the surface. The impactor itself is thought to have been a chondrite asteroid or a comet, not a nickel-iron asteroid. And the molten rock that came up would itself have come from rock that had gone through various processes that could separate and concentrate its components. Those are the kind of ores you'd expect to find on the moon, but even then you wouldn't expect to find as much of them.

    Phobos and Deimos are also within hours of travel and tens of milliseconds of lightspeed delay of the surface of Mars. Once ice mining and propellant manufacture are established on Mars, the easiest way to get to them may well be to land on Mars first, and a Mars colony would provide resupply and shelter in a location close enough for remote operation of equipment on the moons. It would even be feasible to ferry equipment back and forth between Mars and its moons for repair or modification...you could launch a replacement and have the original in your hands for inspection on the same day, when it might be a decade or more before you could get equipment back from an actual asteroid, and the cost of retrieving it would be far higher. Even if they lack valuable mineral or volatile resources, I think they'll be of interest for developing asteroid mining technologies.

  17. #197
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    On reading the discussion in posts #192-#196 it becomes clear that you need to consider the dependencies and interactions between off earth mining on the moon, mars and the asteroid belt together. The linkages between In situ resource utilisation and mining reinforce the point further - it doesn’t really make sense to look at the moon, or mars or the asteroid belt in isolation.

    The momentum beginning to be built around Artemis on the moon is already focusing attention on mining water and volatiles in deep craters at the poles. And all this lunar activity could well spill over into projects exploring extraction of other locations away from the poles and other materials such as valuable metals embedded in impactors.
    Yet in time the lunar experience will help inform early exploration of the mars system, including Phobos and Deimos. The Mars system is so much more remote from cislunar space that the pressure for ISRU will be significant. And the mining potential on mars for volatiles / propellant etc on Mars is very significant as cjameshuff makes clear in his posts.

    But the asteroids have enormous long term potential because of the large surface area with such a wide variety of materials, And the relatively low delta-V s for low mass objects make the near Earth asteroids potentially interesting objects for earlier extraction of water for use in earth orbit - building on the experience of early lunar and then Martian mining experience.

    So in a thread like this it’s difficult to look at asteroid mining in isolation. I guess the key question is what And when will asteroid mining benefit from lunar and then Martian mining experience, And what will be the distinctive contribution which asteroid mining will make in the short (ie a few decades), medium and long term....

  18. #198
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    Quote Originally Posted by DavidLondon View Post
    On reading the discussion in posts #192-#196 it becomes clear that you need to consider the dependencies and interactions between off earth mining on the moon, mars and the asteroid belt together. The linkages between In situ resource utilisation and mining reinforce the point further - it doesn’t really make sense to look at the moon, or mars or the asteroid belt in isolation.

    The momentum beginning to be built around Artemis on the moon is already focusing attention on mining water and volatiles in deep craters at the poles. And all this lunar activity could well spill over into projects exploring extraction of other locations away from the poles and other materials such as valuable metals embedded in impactors.
    Yet in time the lunar experience will help inform early exploration of the mars system, including Phobos and Deimos. The Mars system is so much more remote from cislunar space that the pressure for ISRU will be significant. And the mining potential on mars for volatiles / propellant etc on Mars is very significant as cjameshuff makes clear in his posts.

    But the asteroids have enormous long term potential because of the large surface area with such a wide variety of materials, And the relatively low delta-V s for low mass objects make the near Earth asteroids potentially interesting objects for earlier extraction of water for use in earth orbit - building on the experience of early lunar and then Martian mining experience.

    So in a thread like this it’s difficult to look at asteroid mining in isolation. I guess the key question is what And when will asteroid mining benefit from lunar and then Martian mining experience, And what will be the distinctive contribution which asteroid mining will make in the short (ie a few decades), medium and long term....
    The asteroids are not that low delta-v to reach, even near-Earth asteroids, and travel times are long. A minimum-energy trip to Bennu, for example, takes a little under 5 km/s and 2-4 years, every so often there's a ~16 month opening that takes a bit more delta-v. That'll get you to Mars a good bit faster than a minimum-energy trajectory, well under 9 months. And the more similar the orbit is to Earth's, the longer the time between launch windows is. Low mass only means you can escape an object easily, but the hard part is changing your solar orbit. And those near Earth have long lost all their ices, you'll be left baking water out of hydrated minerals.

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    Quote Originally Posted by cjameshuff View Post
    The asteroids are not that low delta-v to reach, even near-Earth asteroids, and travel times are long. A minimum-energy trip to Bennu, for example, takes a little under 5 km/s and 2-4 years, every so often there's a ~16 month opening that takes a bit more delta-v. That'll get you to Mars a good bit faster than a minimum-energy trajectory, well under 9 months. And the more similar the orbit is to Earth's, the longer the time between launch windows is. Low mass only means you can escape an object easily, but the hard part is changing your solar orbit. And those near Earth have long lost all their ices, you'll be left baking water out of hydrated minerals.
    .
    Thanks cjameshuff. Useful points.

    I have been reading an interesting recent book ‘The Moon’ by Andrew Merton which makes a widely stated point that what matters in space is delta-V and not distance. And that it takes no more delta-V from earth to reach near earth asteroids or even the Martian moons than the earth’s moon.
    I guess this is from a commercial perspective in the context of servicing earth orbit or earth-moon Lagrange point habitats with water for drinking /fuel /air. Once you have established regular supply logistics, maybe the time taken is less important? Like others he concludes that asteroids could become an important source for this demand, potentially competing with and eventually displacing the moon. I guess you are suggesting the business case for this may not be straightforward.
    If so this is a major challenge for early development of asteroid mining to meet emerging demand in cislunar space. This matters because it has been suggested that the off earth economic development over the next several decades (maybe even next 100 years or so) will be mostly in cislunar space.

    So, if the business case for asteroids to meet the earth-moon system demand is weak, we are looking at a longer - 20 or even 30 year plus? - timescale for asteroid mining to take off at any scale.

    Merton also mentions the tensions which exist within the space enthusiast communities, especially in the US, between those favouring early investment focused on the moon against those focused on Mars. I suspect this is linked to US government spending priorities over the next decade or two. (Incidentally I find his comments on these tensions - including a suggestion that it can become fiercely competitive! - quite fascinating).

    For the lunar advocates, NEO asteroid mining of volatiles is perceived as a threat to lunar development which could result in marginalisation
    of lunar investment. I guess the longer term use of asteroids to supply other materials for cislunar orbit are also considered a threat.

    For Mars advocates, the attitude may be more complex. Zubrin and others have stressed that Mars will be the source of choice for any inputs for main belt asteroid mining which can be produced on Mars - citing the delta V benefits cf earth. This case would be strengthened further by using some technology (like a sky hook) to get material off the surface of Mars to Phobos. So there are synergies between Mars and asteroid investment - but perhaps Mars advocates would rather see investment focused on Mars rather than the belt over the next few decades,

    So what I take from this is that, while the long-term (60 plus years?) prospects for asteroid settlement look good, there is likely to be an extended period where main belt Asteroid investment should be linked to, and perhaps follow, investment in the Mars system. And asteroid mining is not as straightforward as suggested in Zubrin’s chapter on ‘asteroids for profits and fun’.

    Do others agree?

  20. 2020-Nov-01, 03:49 PM
    Reason
    Duplication with #199

  21. #200
    Join Date
    Feb 2005
    Posts
    12,001
    Comets might be easier, if the news of them having the consistency of cappuccino froth is correct. I wonder if topology would allow for a “cubing bag” to be vibrated through them, then opened up somehow.

  22. #201
    Join Date
    Mar 2004
    Posts
    19,362
    I’m wondering how many comets have both low delta-v requirements and still have volatiles? Most comets would be hard to reach, but there have been comet missions.

    Oh, sort of related, I ran into an interesting idea I hadn’t heard of. See here:

    https://www.nasa.gov/content/comet-h...-and-low-cost/

    They call it a “comet hitchhiker”. - the idea is to have a trajectory taking a spacecraft past a small body, which it snags by firing a type of harpoon at the object, on a long carbon fiber (thin, high strength) cable, and once it is caught, reels itself in. It’s is a way to transfer momentum from comets or perhaps asteroids to spacecraft, but not catastrophically (it’s like improved lithobreaking). Neat idea, except I wonder how effective the “harpoon” would be.

    Conceivably, this could also be useful for robot miners.

    "The problem with quotes on the Internet is that it is hard to verify their authenticity." — Abraham Lincoln

    I say there is an invisible elf in my backyard. How do you prove that I am wrong?

    The Leif Ericson Cruiser

  23. #202
    Join Date
    Jun 2007
    Posts
    5,933
    Quote Originally Posted by Van Rijn View Post
    I’m wondering how many comets have both low delta-v requirements and still have volatiles? Most comets would be hard to reach, but there have been comet missions.

    Oh, sort of related, I ran into an interesting idea I hadn’t heard of. See here:

    https://www.nasa.gov/content/comet-h...-and-low-cost/

    They call it a “comet hitchhiker”. - the idea is to have a trajectory taking a spacecraft past a small body, which it snags by firing a type of harpoon at the object, on a long carbon fiber (thin, high strength) cable, and once it is caught, reels itself in. It’s is a way to transfer momentum from comets or perhaps asteroids to spacecraft, but not catastrophically (it’s like improved lithobreaking). Neat idea, except I wonder how effective the “harpoon” would be.

    Conceivably, this could also be useful for robot miners.
    You'd need to be able to unreel cable at plausiblility-stretching speeds with carefully controlled drag force for it to actually amount to much delta-v. I have a hard time seeing it working much beyond a few tens of m/s, let alone 10 km/s.

  24. #203
    Join Date
    Sep 2004
    Location
    South Carolina
    Posts
    5,069
    Recent paper on the ethics of asteroid mining:


    https://arxiv.org/abs/2011.03369

    Asteroid Resource Utilization: Ethical Concerns and Progress

    Andrew S. Rivkin, Moses Milazzo, Aparna Venkatesan, Elizabeth Frank, Monica R. Vidaurri, Phil Metzger, Chris Lewicki

    As asteroid mining moves toward reality, the high bar to entering the business may limit participation and increase inequality, reducing or eliminating any benefit gained by marginalized people or developing nations. Consideration of ethical issues is urgently needed, as well as participation in international, not merely multilateral, solutions.
    Do good work. —Virgil Ivan "Gus" Grissom

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