No need to "wipe a small country off the map". Take any of the countless areas on Earth with low populations of ideally nomadic people and offer them a nice chunk of money if they'll be willing to, every few years with long advance warning, move out of the impact zone along with their livestock. Or simply pick an area with no people at all. Greenland would love some extra income, they're big into encouraging mining and have vast glacial landscapes which would be easy to find your impactors on (it'd have no relevant impact on the rate of melt, and meteor-hunting expeditions are often done in Antarctica because they stand out so well against the snow). Shallow seas might be a good option. Salars would be great - generally little to nothing lives there and they're naturally resurfaced annually, so the impactors wouldn't leave a scar. It all depends on how accurate you can be with your impactors.
As for the environment, when you're talking about vaporized rock ablating in the air and plumes of dust being kicked up on impact... it's really not going to be anything compared to what, say, volcanoes do, or wind erosion. Really, I'd expect less environmental impact than a normal terrestrial mine. You could probably even sell your tailings to people who want to build things out of rock from space;)
You don't have to pre-enrich it to those extremes. With a delta-V requirement of only dozens of meters per second, your cost to lob either single-stage concentrated ore, or even raw ore, back to Earth... hmm, let's do some calculations.
Solar panels for space usage are generally cited at 300W/kg (although with a large fixed installation one could probably do a lot better with concentrated solar or nuclear... and there's a lot of room for improvement on that 300 figure.. but let's go with it). 1kg to a NEO surface probably costs around $20k. So about $67 per watt. Let's go with a required delta-V of 50m/s. A coilgun shooting sintered ore would require 0,35 watt hours/kg at 100% efficiency... let's say 0,5 for losses. So $33 pays for 1kg return per hour. Let's say that of every kg you send to Earth 90% reaches the surface and is recovered (the rest ablating on reentry or being lost at the recovery site), so $37/kg. Let's assume that we only want to recover precious metals (even though nickel is worth about $10/kg, for example, and there's lots of other stuff worthwhile), and let's assume that the average precious metal price is $20k/kg (2/3rds the value of gold). If you only got a single hour's worth of returns out of it, you would only need to have refined your precious metal concentration of 0,5% to justify your costs to send it to Earth. From a single hour's worth of returns. If you got 20 years out of it, then your cost per kg to send to Earth (from the power perspective alone) is $0.0002/kg, and 200ppm ore at $20k/kg precious metal would pay for itself 19000x over.
This is why people complaining about the energy required to send things to Earth are not even close to having a valid complaint. It's a non-issue. Getting things to an asteroid is hard, but getting bulk material sent back is easy. It doesn't have to be concentrated. Heck, rather than the energy to send it back one should be more concerned with the energy to mine and sinter it into large shaped blocks for return, that's much more significant (probably in the ballpark of 0,1 to 5kWh per kg, depending on the methods employed - hundreds to thousands of times more than the energy cost to launch it back to Earth). And of course the capital costs to get your hardware sent there - your mining equipment, your coilgun or other launch method (heck, even a torsion catapult would work;) ) sent there, etc and keep it operational. And the vast amounts of prep work that would need to be done to convince investors that the technology is ready. But that said, the economic potential is huge.
Note that if one felt some reason to concentrate ore (probably not economically justifiable), there's lots of relatively easy "first stage" concentration methods available that can eliminate a large chunk of the bulk.
In general, for asteroid mining, even if your capital costs are 1-2 orders of magnitude more per unit throughput, it's probably a solid economic decision. 3 orders of magnitude, maybe. 4 or more orders of magnitude, probably not. Now it's easy to be pessimistic about people's ability to make and launch lightweight, microgravity-and-vacuum tolerant mining hardware, even for a couple orders of magnitude more money. But I personally would not put so much doubt in engineers' ability to do that sort of job. It's not going to happen tomorrow. Or next year. Or next decade. But in decades after that, it's certainly possible.
I don't get your argument. How is saying "I'm not going to take it from you" equivalent to "I hereby claim an asteroid in the name of the United States"? So do you think that the US government is required by the treaty to confiscate the material? Or if not, that some other entity is?
I don't get your line of argument. If a private entity mines an asteroid - the very using of space for the benefit of mankind repeatedly discussed as being beneficial in the OST - then what exactly do you think should happen to it? How should the government treat that material when it returns to Earth? Because everything is in the ownership of someone, whether private or governmental - the law doesn't account for things that no entity has a right or responsibility to.
And anyway: even if the government declared a right to confiscate (rather than an obligation to *not confiscate*) goods returned by private mining - in what way would the claimed right to confiscate the goods be a claim to confiscate the mine? If the US government confiscated a couple tonnes of copper would that be the same as the US government confiscating a copper mine? Of course not, one is the production facility, the other is a product.
1) Rockets are not "quite inefficient". Their Carnot efficiency is usually 80%, net propulsive efficiency around 70% - way better than a gasoline engine (~35%) or diesel engine (40-45%). What they suffer from is totally different: the rocket equation. This mandates exponentially increasing fuel needs to reach a given delta-V, with the exponent proportional to the ISP. But fuel costs have nothing to do with how expensive today's rockets are, we're nowhere near that limit. The Space Shuttle consumed about $2m of propellant to deliver 25 tonnes to LEO, or $80/kg. Using electricity at 100% efficiency and $0,80/kWh it would cost about $0,80/kg to reach orbit. Today's launch costs are about $5k-10k/kg for large launches (the Shuttle was said to be about $18k). So you can see that the fuel costs are just the tiniest fraction, and that it's the engineering challenges of cost-effective production and reuse that are the issue.
2) The "keeping power beaming losses reasonable" is the problem the parent was describing. There is no known way to efficiently transfer power to a small object over tens of thousands of kilometers. Direct transmission isn't even close with conventional conductors, a superconducting line would be many orders of magnitude too heavy, and the cable itself would not be a superconductor, and even if it were its cross section would be way too low. Batteries don't cut it in terms of energy density. And the requirements that climbers be very light precludes nuclear except for the most unrealistically-massive of space elevators. To make RF power beaming remotely efficient over such distances requires a receiving antenna taking up dozens of square kilometers. Laser power beaming means receiving end (solar cell) losses (which even if the solar cells are tuned to a particular frequency you're unlikely to do better than maybe 30-40%) and laser losses (high power lasers are generally in the ballpark of 0,1% efficient; diode lasers can reach up to 25% or so but have far too poor beam quality and are way too weak to be practical). And of course you need a frequency that minimizes atmospheric losses at that.
Perhaps some day power transmission over those distances might become practical, but today it isn't.
This is just the very start of the problems with space elevators, of course. I know space elevators make great books, but they're not practical in the real world. Look into actively suspended structures for your "direct climb to space" needs. They're buildable with today's materials and can get greater than 50% efficiency in energy transfer.
From the perspective of a space elevator, it's not. Read this paper linked from the article. There's no talk of space elevators, that's just their way to entice the reader into listening to them.
That is to say, the space elevator mention is just clickbait.
As the paper notes, "experimentally measured tensile Young's modulus for SWNTs ranges from 320 GPa to 1.47 TPa with the breaking strengths ranging from 13 to 52 GPa". A material with the density of SWNTs is generally considered to need at least 100-120 GPa irreversible yield strength (less than breaking strength) to make a "practical" elevator (although if you read those proposals it's hard to come across with any conclusion other than that they're being way too optimistic even with those numbers). Note: 13-52 GPa for individual tubes. Ropes of multiple tubes are 1-2 orders of magnitude weaker.
So what about these diamond nanothreads?
The yield strength experienced more than 25% reduction (from ~ 75 GPa to ~ 56 GPa) for the DNT-14 when the sample length increases from ~ 13 nm to 26 nm. Afterward, it fluctuates around 56 GPa. Unlike the yield strain, the yield strength for all considered DNTs saturates to a similar value (around 56 GPa) and exhibits a relation irrelevant with the constituent units for the investigated length scope (fro ~13 - 92 nm)
Their data is pretty consistent, with graphs showing a clear dropoff and stabilization around 56 GPa. Obviously nm-sized fibers are pretty worthless for the purposes of an elevator, there'd be way too little Van der Walls holding them together into a rope.
Now, these are just simulations. But more often than not real world seems to underperform simulations rather than overperform, so I wouldn't get too optimistic about the real-world greatly exceeding these figures. For example, early simulations of SWNTs said they'd be around 120GPa; few believe nowadays that they can even approach those figures.
But what about the density side of the equation? After all, a material can be weaker, but if it's correspondingly lighter, then that's not a problem. The density is not in the paper, but this cites the tenacity (breaking strength over mass) as 4.1e10^7 N-m/kg. While the yield strength is going to be a bit less than the breaking strength, it shouldn't be too far off - this means that the density should be somewhere less than - but not too much less than - 1,37g/cm^3. That's on the same order as SWNTs, unfortunately.
Short answer? We're still nowhere even remotely close to being even capable of making a space elevator.
Space elevators face such numerous problems anyway (really don't want to have to go into them all) that they're really not a fruitful avenue of pursuit. We'd do far better to direct such efforts to more realistic access methods, such as a Lofstrom loop or variant thereof, which requires no unobtanium and is far more efficient (space elevators lose huge amounts of energy to transmission losses, throwing away a large chunk of the advantage that they gain from bypassing the rocket equation). Active suspension via recirculating kinetic transfer, by one means or another, is something we can do today.
National ownership and private ownership are two entirely different things. The US has no right to grant or deny access to an asteroid, under the Outer Space Treaty. But once there's property in question within the United States (having been returned to the surface), ownership of that property is a key issue that needs to be decided by law. The US has made clear that it considers that the private property of the company in question. This is in no way "national appropriation by claim of sovereignty" to the asteroid. It's just saying, "Yup, you mined it, you own it, we're not going to confiscate it or anything of the sort"
First, the UK was trying to encroach on waters already owned; no such ownership claim exists to objects in space.
It's not that simple. In each case Iceland was pushing the boundaries of law on ownership of seas. Remember, there was a time where there was no such thing as coastal waters, and then later when there was no concept of an EEZ. In fact, Iceland was the first country to lay claim to an EEZ for fishing (Britain cried foul, but they helped pioneer the concept by laying claim to ocean-bottom mineral resources a couple years earlier in a different kind of EEZ). Now every coastal state has an EEZ, but back then it was a new concept.
For your other two points I think I may have lost the thread here. Or maybe you did. Either way, my point was that larger states can't always successfully bully smaller states by military might in today's international world. I don't see why that wouldn't apply to space as well.
. So far as we know the bulk of that material is stuff that's easy to get here on Earth: silicates, sulfides, iron, nickel etc. Judging from meteors found here on Earth there are exotic materials like iridium, but in trace quantities.
Not at all. In a similar thread I linked to a USGS study on the prospects of space mining that showed that for an entire class of asteroids the average precious metals concentration is 28 ppm, with findings as high as 200ppm. In bulk, not concentrates, no overburden. I mean, that's insanely rich deposits. The richest gold mine on Earth is something like 40ppm - with lots of overburden. Most are 1-2 orders of magnitude less rich than that.
The problem with Earth is that most of the precious metals in the planet have sunk into the depths, with the crust mostly containing only that which has been deposited by later bombardments. But asteroids (with the possible exception of large ones like Ceres) are undifferentiated. Look at 16 Psyche, for example - it makes up 1% of the total mass of the asteroid belt and it's an estimated 90% metal. Ever seen anything like that occurring naturally on Earth?;) Now Psyche itself wouldn't be an ideal target, it's a main belt asteroid, but still, it drives home how much these objects are not like Earth.
The platinum deposits in Canada's Sudbury Basin were delivered by a meteor
I think you're mixing things up. Sudbury is mainly mined for nickel - the platinum is recovered as a secondary product and is not the prime mining target (while not precious, nickel is a rather valuable mineral (nearly twice as valuable as copper), and Sudbury is one of the world's best deposits). And its minerals, while the result of a meteor strike, didn't come from the meteor itself. The meteor (now believed more likely to have been a comet than an asteroid) overwhelmingly converted to vapor and plasma and was blasted into the upper atmosphere and circulated around the Earth. The giant "wound" however, penetrated all the way down to the mantle, which bulged up and diffused with a giant pool of liquified rock and let to melt differentiation mineralization processes, creating areas of very rich deposits. The key issue is that overwhelmingly the minerals at Sudbury are believed to be terrestrial-sourced igneous deposit, even though the concentrations were caused by an impact.
You know, you post as AC but it's really obvious who you are, you have the same writing style everywhere you post;)
Anyway, here's what the treaty actually says:
Outer space, including the moon and other celestial bodies, is not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means.
I don't know, do failed landers actually count? I guess the earth equivalent would be someone sailing to a new island to claim it, launching boats to land on it, but getting stuck on a coral reef on the way in.;)
The missing part is making explicit that an entity owns what it mines and has the right to work the mines it develops. I think given the context it's pretty clear that this was expected, but it is an oversight. You know, if one corporation spent billions clearing the overburden off an asteroid, then another company comes in and just starts mining the ore in question... that's a big problem. It needs to be controlled. Really, it should be allocated out in blocks, with exclusive rights given to use the blocks but only if they're actively working those blocks within a certain timeperiod from their last renewal.
On Earth this is done by nations auctioning off resource extraction rights, but since there's no national ownership of territory in space, no nation could rightfully profit from selling off resource blocks. Blocks would either have to be free or for profits go to an international fund. In the early days, since nobody knows whether space mining actually will play out to be profitable at this point in time, one would expect them to start out free.
But of course all of this would require a new treaty.
Things don't always come down to that. Look at the Cod Wars between Iceland and the UK. Three times Iceland pushed the UK - a nuclear power with hundreds of times its population - back further and further out its shores. The UK had the military ability to crush Iceland like an ant. But Iceland succeeded by combination of making it economically unfeasible for the British to fish Icelandic waters (net cutters, for example) and well-played international geopolitical maneuvering (for example, threatening to give the NATO base at Keflavík to the Soviets if the US didn't exert pressure on the UK, while also successfully positioning itself as a small weak state being bullied by a large powerful one)
Anyway, the Outer Space Treaty was well meaning. Think of the context of the Cold War and how that was all playing out. It seemed logical to think that both nations would begin laying claim to various bodies (or parts thereof), say by landing as many landers as they could to them... which would inherently lead to disputes, just like happens with worthless pieces of land on Earth - with the each side supporting their claim by military means, just like happens on Earth. It was seen as a ripe grounds for an unchecked military escalation, and while it would start out on other celestial bodies, it would progress to LEO and GEO, and then to Earth.
They were probably way overly optimistic about the space of advancement in space technology (remember, this was 1967) and overly pessimistic about everything else. They certainly weren't trying to "block commercial mining"; the goal was simply to prevent a space arms race between rival powers. Quite to the contrary, the treaty talks frequently about encouraging the peaceful use of space for the benefit of humanity. There's just one detail missing, which is to make explicit that corporations or individuals own what they mine. Without that, there won't be much of any "use of space" beyond exploration.
Getting things *to* locations in space is inherently expensive. The cost of getting them *back* is not inherently so, if you don't insist on each return having a custom reentry vehicle and instead just shape it as its own reentry vehicle, with full expectation that it'll suffer some ablation during atmospheric entry. Some NEOs have only dozens of meters per second delta-V to reach earth intercept with an optimal trajectory and timing - a good baseball pitcher could do that unaided;)
They'll say, "oh, it's okay, there's enough of a size difference between those bodies that they don't count". But the thing is that there's no way that most of the current "8 planets" would have cleared their orbits without help from the giants. It's pretty much accepted science in astronomy that Jupiter, and to a lesser extent Saturn, scattered most of the bodies in our solar system. Mars has a Stern-Levison parameter (rating of the ability of a body to scatter small bodies) two orders of magnitude less than Neptune, and Neptune has multiple Pluto-scale bodies in its orbit. Pluto may be small compared to Neptune, but it's not so small in comparison to Mars, yet Mars has two orders magnitude less ability to scatter them. Mars didn't scatter these things away - Jupiter did. Heck, a number of the models show that the planets didn't even form in their current locations.
There's all this misuse of the Stern-Levison parameter out there to say things that it doesn't. The parameter is based around a probabilistic simulation of the body and a bunch of "small bodies" with a mass distribution and orbital distribution similar to our asteroid belt. But of course, that tells you very little - our asteroid belt only has the size and mass distribution that it does today because of the influence of other planets - and when I say "other planets", I really mean overwhelmingly Jupiter (only a tiny fraction of asteroids are in Mars resonances). Jupiter has stopped these bodies from coalescing into larger bodies and scattered the vast majority of its mass elsewhere. That's not the situation that the solar system was in during formation. There were numerous large "planetissimals" scattered around. The Stern-Levison parameter says absolutely nothing about the ability of a body to scatter large planetissimals. And even concerning scattering asteroids, it doesn't state that the scatters are enough to "clear the orbit", only that their angle changes on a pass by more than a given number of degrees.
Basic point: a standard based around the "8 planets" having cleared their orbit is a lie. The science says that most of them aren't responsible for clearing their own orbits.
And while we're at it: what sort of stupid standard puts Mars and Jupiter in the same group but in a different group than Pluto and Ceres? There was a perfectly reasonable standard under discussion at the IAU conference shortly before they switched what they were voting on: a definition built around hydrostatic equlibrium. A lot of the planetary scientists left thinking that this was the version that was going to be voted on, and being happy with either "no definition" or an "equilibrium definition", saw no need to stick around for the final vote. Hydrostatic equilibrium actually is valid science, and it's very meaningful. A body not in hydrostatic equilibrium is generally made of primordial minerals. It's the sort of place you'd go to research, for example, properties of how the solar system formed. A body in hydrostatic equilibrium has undergone mass conversion of its primordial minerals to new forms. It's undergone massive releases of energy (which may still be present, depending), associated action of fluids, etc, and are the sorts of places you would go to study mineralization processes, internal processes or search for life. They're very different bodies, and there's a very simple dividing line - one that's much easier to calculate/measure than a pseudoscience "cleared the neighborhood" standard.
Meh, the Orion design is obsolete anyway - there are much better designs nowadays for nuclear pulse propulsion. Medusa, for example. More efficient, lighter, lower radiation to the crew, easier shock absorption, and so on down the line.
And even the best public transport system generally isnt going to start and stop *exactly* where you need it, so there still is going to be *some* walking. Which some people with disabilities or health problems simply can't manage. And to achieve a good public transport system - with frequent stops, densely placed stops, relatively direct routes and affordable prices - is entirely dependent on population density far more than it is on "will". In places with high density, it's a relatively straightforward process to have a good public transport system. In places with moderate to low density, it can be difficult to nearly impossible. And weaknesses in public transport system are a viscious cycle: the less frequent the stops, the further spaced out they are, the longer the transit times, and the more expensive the rides - the fewer people will ride them. The fewer that ride the less frequent you have to have the stops, the further apart they need to be, the less direct the routes, and the less affordable the prices.
That was not my point. Ofc we can improve ISP. No idea how much that improves either 'performance' or drops price.
It improves performance a *lot*. As for price, it depends on how expensive that rocket system is. For first stages, an improvement in ISP's effect on the size of the rocket isn't that much greater than linear. But the further up the delta-V chain the engine is used, the more of an impact it has on everything that was used to get it there. An extra hundred sec ISP on a first stage might reduce the system mass by a third; on a second stage up to LEO, maybe cut it in half; on a kick stage for a Mars transfer orbit, maybe cut it by two thirds. On an ascent stage from the surface of Mars... well you get the idea. Shrinking down a rocket to a small fraction of its size - fuel, tankage, and engines - well, that's really significant. ISP is very, very important for upper stages. So you can afford to pay quite a bit for those top stages if it improves their performance. Just not an "unlimited" amount.
There is no way a high tech electrical engine will improve its performance by 10% regardless how much money or time you put into it: the efficiency is already between 98.5% - 99.5%, up to 99.9% in some cases.
This is getting a bit offtopic, but at least the electric engines in EVs don't usually run at nearly that high. Depending on the type they might average 85 to 94% on average. It varies over their load cycle.
Regarding rockets: there is simply not much margin anymore in changing the form of the exhaust tube, burn chamber etc
Actually you can. The general principles of how rocket engines work are fixed, of course - your exhaust will never exceed its local speed of sound in the throat, and then you want to expand it as close to ambient pressure as you want. But the details vary greatly. There's bell nozzles, linear nozzles, annular nozzles, aerospikes, throatless nozzles, atmospheric wake compression, and on and on. There's tons of different ways - developed, in development, and in theory - to pump and inject your propellants - where they need to be pumped at all. Even many propellants that are traditionally thought of as being in one state can be implemented in other states. There's various ways - developed, in development, and in theory - to prevent nozzle erosion. To improve regeneration. To reduce mass. And on and on and on. Rocket combustion is a rather complex thing and we're still trying to get a handle on it. Do you know that we still really don't know how aluminum burns in solid rocket propellant? There's something like five different competing theories. I mean, things like this are a Big Freaking Deal(TM), especially when such small improvements in upper stage ISP have such significance for lower stage mass. And even on your lower stages there's a lot of things that have a big effect on your system cost. For example, how to stop resonant shocks from ripping them up - a lot of people don't realize that one of the main benefits of adding aluminum first stage to propellant mixes is that the droplets of burning aluminum damp shocks. (yeah, it increases ISP too by raising the exhaust temperature, but it also has disadvantages, such as not contributing to expansion, slowing down gases (particularly near the nozzle), and impacting/eroding the throat (or even forming an accumulating slag)
Re, nuclear+chemical. There are proposals for this. The main issue isn't efficiency - the extra chemical energy doesn't make that much of a difference - but thrust. The downside to nuclear thermal is that the reactor is so heavy (fission is like that, unfortunately) that the mass ratio is only something like 3-4:1. That's really bad (you generally get 15-20:1 or even better for a chemical first stage). So the approach is to inject oxygen early in the ascent phase for added thrust, but only run on hydrogen higher up when gravity losses are lower. I'm really not that sanguine
Yes, people to run robots and comm time on the DSN. We're not talking about massive expenses here. The real expenses are the capital costs.
And also didn't mention that you can't just lob chunks of metal straight to Earth's surface,
Actually, you really just can. Even random rocks from space - not shaped for optimal entry shape, not cemented together by anything yet what nature chose to gie them - do this all the time. They have to be between a certain size range (too little and the whole thing ablates; too large and it explodes, either in the atmosphere or on impact), but the random creations of nature do it; delberately shaped and sintered projectiles should have no trouble with it, with (proportional to their mass) relatively little burnoff.
You would, of course, need a rather large area designated as the impact area; even with very precise aiming, by the time they get to Earth and undergo reentry the random variables will spread them out over a sizeable chunk of land. A large salar might be ideal, since they get resurfaced periodically so the impacts wouldn't be damaging the landscape.
By your same logic, the mining of minerals on Earth would be zero dollars per gram if the equipment was solar powered and automated
It's almost as if I didn't discuss capital and ongoing costs in my above post.
Launch costs really are key to the rate of development at the very least, in that they limit the rate in which funding can be raised for the necessary exploratory and test craft to be launched. Even if the economics for operating a mine on a NEO works out really well at present launch costs, you have to prove that you can do it before you can raise the billions to build it. And to prove that you can do it you have to launch a number of missions while you're still relatively poorly funded. They face the same problem that Bigelow has faced - a probably reasonable business plan but the early phases hinging around factors that they don't control.
It does nobody any good to pretend that the lack of a space economy is because investors are cowards and morons
I think you need to go back and read my last post again, particularly all of the "it's too early to say"/""we don't know"/"but time will tell"/etc lines. I'm not saying that at all. I'm saying that there very well could be a compelling case for asteroid mining even without any radical changes in space technologies. But there's a great deal of work to prove that before we can get to that point.
Are the other variants more dialectal? In addition to huoji ( / ) (fire chicken) what I read states that there's also qimianniao ( / ) (seven-faced bird), tujinji ( / ) (cough up a brocade chicken) and tushouji ( / ) (cough up a ribbon chicken)
On the other hand I would want to talk to Archimedes
You speak ancient Greek and can communicate with the dead? Okay, I'm impressed.;)
Thanksgiving trivia for the day: the word for "turkey" comes from extensive and long-running confusion about where the bird came from. For example, in English it's called Turkey. In Turkey it's called "hindi", referring to India. In India it's called Peru. In Peru it's called "pavo", referring to peacocks, which are native to south and southeast asia, such as India (cyclic there), Cambodia, Malaysia, etc. In Cambodia (Khmer) it's called "moan barang", meaning "French chicken", while in Malaysia it's referred to as "ayam belanda", meaning "Dutch chicken". Both of those in turn think it comes from India: in French it's called "dinde" (from "poulet d’Inde", aka "chicken of India"), while in Dutch it's "kalkoen", referring to a place in India. Greek has a number of local dialectal names, such as misírka, meaning "egyptian bird", while in Egypt it's called dk rm, meaning the Greek bird (even though the latter part of the name derives from Rome - the Italians, by the way, thinking it comes from India). One variant of Arabic even credits it to Ethiopia.
A couple languages deserve special credit for their words:
Best accuracy: Miami indian - nalaaohki pileewa, meaning "native fowl" Worst accuracy: A tie between Albanian (gjel deti, "sea rooster"); Tamil (vaan kozhi, "sky chicken"); and Swahili (bata mzinga, "the great duck") Most creative: Mandarin - many names with meanings such as "cough up a ribbon chicken" and "seven-faced bird" Least creative: Blackfoot: ómahksipi'kssíí, meaning "big bird". Hmm...
Except that your cost examples are based around the price of rocks brought back as a "oh and we're going to do this too" mission add-on. It would be like as if I flew to America to visit my grandmother for Christmas via purchasing a $700 plane ticket and while I was there I bought a $15 sweater and brought it back, and you said, "See, she paid $715 to go to America and buy a sweater - American sweaters are unjustifiably expensive!" You simply cannot take the cost of the Apollo mission, divide by the mass of rocks returned, and pretend that that's anything even remotely close to the cost of retrieval per gram.
What's the actual cost of space mining? It's too early to say. But the mining of NEOs could be as little as *zero* dollars per gram (excluding capital costs and maintenance), insomuch as it would be possible to fire sintered minerals (using solar power) via a coilgun onto an aerocapture trajectory. You don't actually have to have a rocket to bring them back. What would the capital costs be like? That we don't know - again, it's too early to say. But it's normal for large mines on Earth to cost billions of dollars, and what one can do with a large mine on Earth one could do with a vastly smaller mine on a NEO due to the superb mineral concentrations on some of them. There are a number of peer-reviewed papers putting forth that it could work out to be economical (I was reading one from the USGS just the other day) as a result of this.
But time will tell. It's going to take a lot more basic research and engineering before we can get a good sense of just what it would cost to get what sort of throughput of what sort of minerals.
As usual, "pop science" news overstated the case. We know that there's ppm quantities of water in most lunar regolith, but that's not what people usually talk about. There's also a good degree of confidence that there's a lot of *hydroxyl* group in a lot of places on the moon. But the connection between that and the group being specifically water is much weaker - and many missions sent to detect water in likely areas have failed. The best evidence for water have come from Chandrayaan and LRO, examining craters that were considered likely to find ice. They have both failed to find "slabs" of ice in the crater, but found evidence for ice grains in the regolith - about 5% according to LRO. On Earth that would be considered dry soil, but it's something at least.
Of course, if you're constraining yourself to such craters, you're really constraining where you can go. On the general lunar surface, the sun bakes water out of the regolith.
Iron, aluminum, and titanium are very useful for making things
They're all tightly locked up as oxides, without the raw materials that we use to refine them on Earth being available. There are however tiny grains of raw iron in the regolith, so there is some potential to comb it out magnetically. Still, asteroids present by far better resource options in much greater concentrations.
There really is just no reason to do your work in a gravity well as deep as the moon's, and then have to break out of it, when you can just mine NEOs. Yes, it's "half the gravity of Mars", but it's vastly more than asteroids. Rockets with a couple thousand spare m/s delta-V don't just grow on lunar trees.
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No need to "wipe a small country off the map". Take any of the countless areas on Earth with low populations of ideally nomadic people and offer them a nice chunk of money if they'll be willing to, every few years with long advance warning, move out of the impact zone along with their livestock. Or simply pick an area with no people at all. Greenland would love some extra income, they're big into encouraging mining and have vast glacial landscapes which would be easy to find your impactors on (it'd have no relevant impact on the rate of melt, and meteor-hunting expeditions are often done in Antarctica because they stand out so well against the snow). Shallow seas might be a good option. Salars would be great - generally little to nothing lives there and they're naturally resurfaced annually, so the impactors wouldn't leave a scar. It all depends on how accurate you can be with your impactors.
As for the environment, when you're talking about vaporized rock ablating in the air and plumes of dust being kicked up on impact... it's really not going to be anything compared to what, say, volcanoes do, or wind erosion. Really, I'd expect less environmental impact than a normal terrestrial mine. You could probably even sell your tailings to people who want to build things out of rock from space ;)
You don't have to pre-enrich it to those extremes. With a delta-V requirement of only dozens of meters per second, your cost to lob either single-stage concentrated ore, or even raw ore, back to Earth... hmm, let's do some calculations.
Solar panels for space usage are generally cited at 300W/kg (although with a large fixed installation one could probably do a lot better with concentrated solar or nuclear... and there's a lot of room for improvement on that 300 figure.. but let's go with it). 1kg to a NEO surface probably costs around $20k. So about $67 per watt. Let's go with a required delta-V of 50m/s. A coilgun shooting sintered ore would require 0,35 watt hours/kg at 100% efficiency... let's say 0,5 for losses. So $33 pays for 1kg return per hour. Let's say that of every kg you send to Earth 90% reaches the surface and is recovered (the rest ablating on reentry or being lost at the recovery site), so $37/kg. Let's assume that we only want to recover precious metals (even though nickel is worth about $10/kg, for example, and there's lots of other stuff worthwhile), and let's assume that the average precious metal price is $20k/kg (2/3rds the value of gold). If you only got a single hour's worth of returns out of it, you would only need to have refined your precious metal concentration of 0,5% to justify your costs to send it to Earth. From a single hour's worth of returns. If you got 20 years out of it, then your cost per kg to send to Earth (from the power perspective alone) is $0.0002/kg, and 200ppm ore at $20k/kg precious metal would pay for itself 19000x over.
This is why people complaining about the energy required to send things to Earth are not even close to having a valid complaint. It's a non-issue. Getting things to an asteroid is hard, but getting bulk material sent back is easy. It doesn't have to be concentrated. Heck, rather than the energy to send it back one should be more concerned with the energy to mine and sinter it into large shaped blocks for return, that's much more significant (probably in the ballpark of 0,1 to 5kWh per kg, depending on the methods employed - hundreds to thousands of times more than the energy cost to launch it back to Earth). And of course the capital costs to get your hardware sent there - your mining equipment, your coilgun or other launch method (heck, even a torsion catapult would work ;) ) sent there, etc and keep it operational. And the vast amounts of prep work that would need to be done to convince investors that the technology is ready. But that said, the economic potential is huge.
Note that if one felt some reason to concentrate ore (probably not economically justifiable), there's lots of relatively easy "first stage" concentration methods available that can eliminate a large chunk of the bulk.
In general, for asteroid mining, even if your capital costs are 1-2 orders of magnitude more per unit throughput, it's probably a solid economic decision. 3 orders of magnitude, maybe. 4 or more orders of magnitude, probably not. Now it's easy to be pessimistic about people's ability to make and launch lightweight, microgravity-and-vacuum tolerant mining hardware, even for a couple orders of magnitude more money. But I personally would not put so much doubt in engineers' ability to do that sort of job. It's not going to happen tomorrow. Or next year. Or next decade. But in decades after that, it's certainly possible.
I don't get your argument. How is saying "I'm not going to take it from you" equivalent to "I hereby claim an asteroid in the name of the United States"? So do you think that the US government is required by the treaty to confiscate the material? Or if not, that some other entity is?
I don't get your line of argument. If a private entity mines an asteroid - the very using of space for the benefit of mankind repeatedly discussed as being beneficial in the OST - then what exactly do you think should happen to it? How should the government treat that material when it returns to Earth? Because everything is in the ownership of someone, whether private or governmental - the law doesn't account for things that no entity has a right or responsibility to.
And anyway: even if the government declared a right to confiscate (rather than an obligation to *not confiscate*) goods returned by private mining - in what way would the claimed right to confiscate the goods be a claim to confiscate the mine? If the US government confiscated a couple tonnes of copper would that be the same as the US government confiscating a copper mine? Of course not, one is the production facility, the other is a product.
Your post is simply incorrect.
1) Rockets are not "quite inefficient". Their Carnot efficiency is usually 80%, net propulsive efficiency around 70% - way better than a gasoline engine (~35%) or diesel engine (40-45%). What they suffer from is totally different: the rocket equation. This mandates exponentially increasing fuel needs to reach a given delta-V, with the exponent proportional to the ISP. But fuel costs have nothing to do with how expensive today's rockets are, we're nowhere near that limit. The Space Shuttle consumed about $2m of propellant to deliver 25 tonnes to LEO, or $80/kg. Using electricity at 100% efficiency and $0,80/kWh it would cost about $0,80/kg to reach orbit. Today's launch costs are about $5k-10k/kg for large launches (the Shuttle was said to be about $18k). So you can see that the fuel costs are just the tiniest fraction, and that it's the engineering challenges of cost-effective production and reuse that are the issue.
2) The "keeping power beaming losses reasonable" is the problem the parent was describing. There is no known way to efficiently transfer power to a small object over tens of thousands of kilometers. Direct transmission isn't even close with conventional conductors, a superconducting line would be many orders of magnitude too heavy, and the cable itself would not be a superconductor, and even if it were its cross section would be way too low. Batteries don't cut it in terms of energy density. And the requirements that climbers be very light precludes nuclear except for the most unrealistically-massive of space elevators. To make RF power beaming remotely efficient over such distances requires a receiving antenna taking up dozens of square kilometers. Laser power beaming means receiving end (solar cell) losses (which even if the solar cells are tuned to a particular frequency you're unlikely to do better than maybe 30-40%) and laser losses (high power lasers are generally in the ballpark of 0,1% efficient; diode lasers can reach up to 25% or so but have far too poor beam quality and are way too weak to be practical). And of course you need a frequency that minimizes atmospheric losses at that.
Perhaps some day power transmission over those distances might become practical, but today it isn't.
This is just the very start of the problems with space elevators, of course. I know space elevators make great books, but they're not practical in the real world. Look into actively suspended structures for your "direct climb to space" needs. They're buildable with today's materials and can get greater than 50% efficiency in energy transfer.
From the perspective of a space elevator, it's not. Read this paper linked from the article. There's no talk of space elevators, that's just their way to entice the reader into listening to them.
That is to say, the space elevator mention is just clickbait.
As the paper notes, "experimentally measured tensile Young's modulus for SWNTs ranges from 320 GPa to 1.47 TPa with the breaking strengths ranging from 13 to 52 GPa". A material with the density of SWNTs is generally considered to need at least 100-120 GPa irreversible yield strength (less than breaking strength) to make a "practical" elevator (although if you read those proposals it's hard to come across with any conclusion other than that they're being way too optimistic even with those numbers). Note: 13-52 GPa for individual tubes. Ropes of multiple tubes are 1-2 orders of magnitude weaker.
So what about these diamond nanothreads?
Their data is pretty consistent, with graphs showing a clear dropoff and stabilization around 56 GPa. Obviously nm-sized fibers are pretty worthless for the purposes of an elevator, there'd be way too little Van der Walls holding them together into a rope.
Now, these are just simulations. But more often than not real world seems to underperform simulations rather than overperform, so I wouldn't get too optimistic about the real-world greatly exceeding these figures. For example, early simulations of SWNTs said they'd be around 120GPa; few believe nowadays that they can even approach those figures.
But what about the density side of the equation? After all, a material can be weaker, but if it's correspondingly lighter, then that's not a problem. The density is not in the paper, but this cites the tenacity (breaking strength over mass) as 4.1e10^7 N-m/kg. While the yield strength is going to be a bit less than the breaking strength, it shouldn't be too far off - this means that the density should be somewhere less than - but not too much less than - 1,37g/cm^3. That's on the same order as SWNTs, unfortunately.
Short answer? We're still nowhere even remotely close to being even capable of making a space elevator.
Space elevators face such numerous problems anyway (really don't want to have to go into them all) that they're really not a fruitful avenue of pursuit. We'd do far better to direct such efforts to more realistic access methods, such as a Lofstrom loop or variant thereof, which requires no unobtanium and is far more efficient (space elevators lose huge amounts of energy to transmission losses, throwing away a large chunk of the advantage that they gain from bypassing the rocket equation). Active suspension via recirculating kinetic transfer, by one means or another, is something we can do today.
National ownership and private ownership are two entirely different things. The US has no right to grant or deny access to an asteroid, under the Outer Space Treaty. But once there's property in question within the United States (having been returned to the surface), ownership of that property is a key issue that needs to be decided by law. The US has made clear that it considers that the private property of the company in question. This is in no way "national appropriation by claim of sovereignty" to the asteroid. It's just saying, "Yup, you mined it, you own it, we're not going to confiscate it or anything of the sort"
It's not that simple. In each case Iceland was pushing the boundaries of law on ownership of seas. Remember, there was a time where there was no such thing as coastal waters, and then later when there was no concept of an EEZ. In fact, Iceland was the first country to lay claim to an EEZ for fishing (Britain cried foul, but they helped pioneer the concept by laying claim to ocean-bottom mineral resources a couple years earlier in a different kind of EEZ). Now every coastal state has an EEZ, but back then it was a new concept.
For your other two points I think I may have lost the thread here. Or maybe you did. Either way, my point was that larger states can't always successfully bully smaller states by military might in today's international world. I don't see why that wouldn't apply to space as well.
Not at all. In a similar thread I linked to a USGS study on the prospects of space mining that showed that for an entire class of asteroids the average precious metals concentration is 28 ppm, with findings as high as 200ppm. In bulk, not concentrates, no overburden. I mean, that's insanely rich deposits. The richest gold mine on Earth is something like 40ppm - with lots of overburden. Most are 1-2 orders of magnitude less rich than that.
The problem with Earth is that most of the precious metals in the planet have sunk into the depths, with the crust mostly containing only that which has been deposited by later bombardments. But asteroids (with the possible exception of large ones like Ceres) are undifferentiated. Look at 16 Psyche, for example - it makes up 1% of the total mass of the asteroid belt and it's an estimated 90% metal. Ever seen anything like that occurring naturally on Earth? ;) Now Psyche itself wouldn't be an ideal target, it's a main belt asteroid, but still, it drives home how much these objects are not like Earth.
I think you're mixing things up. Sudbury is mainly mined for nickel - the platinum is recovered as a secondary product and is not the prime mining target (while not precious, nickel is a rather valuable mineral (nearly twice as valuable as copper), and Sudbury is one of the world's best deposits). And its minerals, while the result of a meteor strike, didn't come from the meteor itself. The meteor (now believed more likely to have been a comet than an asteroid) overwhelmingly converted to vapor and plasma and was blasted into the upper atmosphere and circulated around the Earth. The giant "wound" however, penetrated all the way down to the mantle, which bulged up and diffused with a giant pool of liquified rock and let to melt differentiation mineralization processes, creating areas of very rich deposits. The key issue is that overwhelmingly the minerals at Sudbury are believed to be terrestrial-sourced igneous deposit, even though the concentrations were caused by an impact.
You know, you post as AC but it's really obvious who you are, you have the same writing style everywhere you post ;)
Anyway, here's what the treaty actually says:
Any questions?
I don't know, do failed landers actually count? I guess the earth equivalent would be someone sailing to a new island to claim it, launching boats to land on it, but getting stuck on a coral reef on the way in. ;)
The missing part is making explicit that an entity owns what it mines and has the right to work the mines it develops. I think given the context it's pretty clear that this was expected, but it is an oversight. You know, if one corporation spent billions clearing the overburden off an asteroid, then another company comes in and just starts mining the ore in question... that's a big problem. It needs to be controlled. Really, it should be allocated out in blocks, with exclusive rights given to use the blocks but only if they're actively working those blocks within a certain timeperiod from their last renewal.
On Earth this is done by nations auctioning off resource extraction rights, but since there's no national ownership of territory in space, no nation could rightfully profit from selling off resource blocks. Blocks would either have to be free or for profits go to an international fund. In the early days, since nobody knows whether space mining actually will play out to be profitable at this point in time, one would expect them to start out free.
But of course all of this would require a new treaty.
Things don't always come down to that. Look at the Cod Wars between Iceland and the UK. Three times Iceland pushed the UK - a nuclear power with hundreds of times its population - back further and further out its shores. The UK had the military ability to crush Iceland like an ant. But Iceland succeeded by combination of making it economically unfeasible for the British to fish Icelandic waters (net cutters, for example) and well-played international geopolitical maneuvering (for example, threatening to give the NATO base at Keflavík to the Soviets if the US didn't exert pressure on the UK, while also successfully positioning itself as a small weak state being bullied by a large powerful one)
Anyway, the Outer Space Treaty was well meaning. Think of the context of the Cold War and how that was all playing out. It seemed logical to think that both nations would begin laying claim to various bodies (or parts thereof), say by landing as many landers as they could to them... which would inherently lead to disputes, just like happens with worthless pieces of land on Earth - with the each side supporting their claim by military means, just like happens on Earth. It was seen as a ripe grounds for an unchecked military escalation, and while it would start out on other celestial bodies, it would progress to LEO and GEO, and then to Earth.
They were probably way overly optimistic about the space of advancement in space technology (remember, this was 1967) and overly pessimistic about everything else. They certainly weren't trying to "block commercial mining"; the goal was simply to prevent a space arms race between rival powers. Quite to the contrary, the treaty talks frequently about encouraging the peaceful use of space for the benefit of humanity. There's just one detail missing, which is to make explicit that corporations or individuals own what they mine. Without that, there won't be much of any "use of space" beyond exploration.
Getting things *to* locations in space is inherently expensive. The cost of getting them *back* is not inherently so, if you don't insist on each return having a custom reentry vehicle and instead just shape it as its own reentry vehicle, with full expectation that it'll suffer some ablation during atmospheric entry. Some NEOs have only dozens of meters per second delta-V to reach earth intercept with an optimal trajectory and timing - a good baseball pitcher could do that unaided ;)
It could be dialectal. OR-eee-on is the proper pronunciation here in Iceland.
They'll say, "oh, it's okay, there's enough of a size difference between those bodies that they don't count". But the thing is that there's no way that most of the current "8 planets" would have cleared their orbits without help from the giants. It's pretty much accepted science in astronomy that Jupiter, and to a lesser extent Saturn, scattered most of the bodies in our solar system. Mars has a Stern-Levison parameter (rating of the ability of a body to scatter small bodies) two orders of magnitude less than Neptune, and Neptune has multiple Pluto-scale bodies in its orbit. Pluto may be small compared to Neptune, but it's not so small in comparison to Mars, yet Mars has two orders magnitude less ability to scatter them. Mars didn't scatter these things away - Jupiter did. Heck, a number of the models show that the planets didn't even form in their current locations.
There's all this misuse of the Stern-Levison parameter out there to say things that it doesn't. The parameter is based around a probabilistic simulation of the body and a bunch of "small bodies" with a mass distribution and orbital distribution similar to our asteroid belt. But of course, that tells you very little - our asteroid belt only has the size and mass distribution that it does today because of the influence of other planets - and when I say "other planets", I really mean overwhelmingly Jupiter (only a tiny fraction of asteroids are in Mars resonances). Jupiter has stopped these bodies from coalescing into larger bodies and scattered the vast majority of its mass elsewhere. That's not the situation that the solar system was in during formation. There were numerous large "planetissimals" scattered around. The Stern-Levison parameter says absolutely nothing about the ability of a body to scatter large planetissimals. And even concerning scattering asteroids, it doesn't state that the scatters are enough to "clear the orbit", only that their angle changes on a pass by more than a given number of degrees.
Basic point: a standard based around the "8 planets" having cleared their orbit is a lie. The science says that most of them aren't responsible for clearing their own orbits.
And while we're at it: what sort of stupid standard puts Mars and Jupiter in the same group but in a different group than Pluto and Ceres? There was a perfectly reasonable standard under discussion at the IAU conference shortly before they switched what they were voting on: a definition built around hydrostatic equlibrium. A lot of the planetary scientists left thinking that this was the version that was going to be voted on, and being happy with either "no definition" or an "equilibrium definition", saw no need to stick around for the final vote. Hydrostatic equilibrium actually is valid science, and it's very meaningful. A body not in hydrostatic equilibrium is generally made of primordial minerals. It's the sort of place you'd go to research, for example, properties of how the solar system formed. A body in hydrostatic equilibrium has undergone mass conversion of its primordial minerals to new forms. It's undergone massive releases of energy (which may still be present, depending), associated action of fluids, etc, and are the sorts of places you would go to study mineralization processes, internal processes or search for life. They're very different bodies, and there's a very simple dividing line - one that's much easier to calculate/measure than a pseudoscience "cleared the neighborhood" standard.
Meh, the Orion design is obsolete anyway - there are much better designs nowadays for nuclear pulse propulsion. Medusa, for example. More efficient, lighter, lower radiation to the crew, easier shock absorption, and so on down the line.
I couldn't stop thinking, "NASA invented time travel - I knew it! Insane theories one, regular theories a billion!"
Love the quality of the debates here on Slashdot.
Come on, you two haven't called each other poopy-heads yet!
And even the best public transport system generally isnt going to start and stop *exactly* where you need it, so there still is going to be *some* walking. Which some people with disabilities or health problems simply can't manage. And to achieve a good public transport system - with frequent stops, densely placed stops, relatively direct routes and affordable prices - is entirely dependent on population density far more than it is on "will". In places with high density, it's a relatively straightforward process to have a good public transport system. In places with moderate to low density, it can be difficult to nearly impossible. And weaknesses in public transport system are a viscious cycle: the less frequent the stops, the further spaced out they are, the longer the transit times, and the more expensive the rides - the fewer people will ride them. The fewer that ride the less frequent you have to have the stops, the further apart they need to be, the less direct the routes, and the less affordable the prices.
It improves performance a *lot*. As for price, it depends on how expensive that rocket system is. For first stages, an improvement in ISP's effect on the size of the rocket isn't that much greater than linear. But the further up the delta-V chain the engine is used, the more of an impact it has on everything that was used to get it there. An extra hundred sec ISP on a first stage might reduce the system mass by a third; on a second stage up to LEO, maybe cut it in half; on a kick stage for a Mars transfer orbit, maybe cut it by two thirds. On an ascent stage from the surface of Mars... well you get the idea. Shrinking down a rocket to a small fraction of its size - fuel, tankage, and engines - well, that's really significant. ISP is very, very important for upper stages. So you can afford to pay quite a bit for those top stages if it improves their performance. Just not an "unlimited" amount.
This is getting a bit offtopic, but at least the electric engines in EVs don't usually run at nearly that high. Depending on the type they might average 85 to 94% on average. It varies over their load cycle.
Actually you can. The general principles of how rocket engines work are fixed, of course - your exhaust will never exceed its local speed of sound in the throat, and then you want to expand it as close to ambient pressure as you want. But the details vary greatly. There's bell nozzles, linear nozzles, annular nozzles, aerospikes, throatless nozzles, atmospheric wake compression, and on and on. There's tons of different ways - developed, in development, and in theory - to pump and inject your propellants - where they need to be pumped at all. Even many propellants that are traditionally thought of as being in one state can be implemented in other states. There's various ways - developed, in development, and in theory - to prevent nozzle erosion. To improve regeneration. To reduce mass. And on and on and on. Rocket combustion is a rather complex thing and we're still trying to get a handle on it. Do you know that we still really don't know how aluminum burns in solid rocket propellant? There's something like five different competing theories. I mean, things like this are a Big Freaking Deal(TM), especially when such small improvements in upper stage ISP have such significance for lower stage mass. And even on your lower stages there's a lot of things that have a big effect on your system cost. For example, how to stop resonant shocks from ripping them up - a lot of people don't realize that one of the main benefits of adding aluminum first stage to propellant mixes is that the droplets of burning aluminum damp shocks. (yeah, it increases ISP too by raising the exhaust temperature, but it also has disadvantages, such as not contributing to expansion, slowing down gases (particularly near the nozzle), and impacting/eroding the throat (or even forming an accumulating slag)
Re, nuclear+chemical. There are proposals for this. The main issue isn't efficiency - the extra chemical energy doesn't make that much of a difference - but thrust. The downside to nuclear thermal is that the reactor is so heavy (fission is like that, unfortunately) that the mass ratio is only something like 3-4:1. That's really bad (you generally get 15-20:1 or even better for a chemical first stage). So the approach is to inject oxygen early in the ascent phase for added thrust, but only run on hydrogen higher up when gravity losses are lower. I'm really not that sanguine
Yes, people to run robots and comm time on the DSN. We're not talking about massive expenses here. The real expenses are the capital costs.
Actually, you really just can. Even random rocks from space - not shaped for optimal entry shape, not cemented together by anything yet what nature chose to gie them - do this all the time. They have to be between a certain size range (too little and the whole thing ablates; too large and it explodes, either in the atmosphere or on impact), but the random creations of nature do it; delberately shaped and sintered projectiles should have no trouble with it, with (proportional to their mass) relatively little burnoff.
You would, of course, need a rather large area designated as the impact area; even with very precise aiming, by the time they get to Earth and undergo reentry the random variables will spread them out over a sizeable chunk of land. A large salar might be ideal, since they get resurfaced periodically so the impacts wouldn't be damaging the landscape.
It's almost as if I didn't discuss capital and ongoing costs in my above post.
Launch costs really are key to the rate of development at the very least, in that they limit the rate in which funding can be raised for the necessary exploratory and test craft to be launched. Even if the economics for operating a mine on a NEO works out really well at present launch costs, you have to prove that you can do it before you can raise the billions to build it. And to prove that you can do it you have to launch a number of missions while you're still relatively poorly funded. They face the same problem that Bigelow has faced - a probably reasonable business plan but the early phases hinging around factors that they don't control.
I think you need to go back and read my last post again, particularly all of the "it's too early to say"/""we don't know"/"but time will tell"/etc lines. I'm not saying that at all. I'm saying that there very well could be a compelling case for asteroid mining even without any radical changes in space technologies. But there's a great deal of work to prove that before we can get to that point.
Are the other variants more dialectal? In addition to huoji ( / ) (fire chicken) what I read states that there's also qimianniao ( / ) (seven-faced bird), tujinji ( / ) (cough up a brocade chicken) and tushouji ( / ) (cough up a ribbon chicken)
(hope Slashdot doesn't mess up the characters)
You speak ancient Greek and can communicate with the dead? Okay, I'm impressed. ;)
Thanksgiving trivia for the day: the word for "turkey" comes from extensive and long-running confusion about where the bird came from. For example, in English it's called Turkey. In Turkey it's called "hindi", referring to India. In India it's called Peru. In Peru it's called "pavo", referring to peacocks, which are native to south and southeast asia, such as India (cyclic there), Cambodia, Malaysia, etc. In Cambodia (Khmer) it's called "moan barang", meaning "French chicken", while in Malaysia it's referred to as "ayam belanda", meaning "Dutch chicken". Both of those in turn think it comes from India: in French it's called "dinde" (from "poulet d’Inde", aka "chicken of India"), while in Dutch it's "kalkoen", referring to a place in India. Greek has a number of local dialectal names, such as misírka, meaning "egyptian bird", while in Egypt it's called dk rm, meaning the Greek bird (even though the latter part of the name derives from Rome - the Italians, by the way, thinking it comes from India). One variant of Arabic even credits it to Ethiopia.
A couple languages deserve special credit for their words:
Best accuracy: Miami indian - nalaaohki pileewa, meaning "native fowl"
Worst accuracy: A tie between Albanian (gjel deti, "sea rooster"); Tamil (vaan kozhi, "sky chicken"); and Swahili (bata mzinga, "the great duck")
Most creative: Mandarin - many names with meanings such as "cough up a ribbon chicken" and "seven-faced bird"
Least creative: Blackfoot: ómahksipi'kssíí, meaning "big bird". Hmm...
Except that your cost examples are based around the price of rocks brought back as a "oh and we're going to do this too" mission add-on. It would be like as if I flew to America to visit my grandmother for Christmas via purchasing a $700 plane ticket and while I was there I bought a $15 sweater and brought it back, and you said, "See, she paid $715 to go to America and buy a sweater - American sweaters are unjustifiably expensive!" You simply cannot take the cost of the Apollo mission, divide by the mass of rocks returned, and pretend that that's anything even remotely close to the cost of retrieval per gram.
What's the actual cost of space mining? It's too early to say. But the mining of NEOs could be as little as *zero* dollars per gram (excluding capital costs and maintenance), insomuch as it would be possible to fire sintered minerals (using solar power) via a coilgun onto an aerocapture trajectory. You don't actually have to have a rocket to bring them back. What would the capital costs be like? That we don't know - again, it's too early to say. But it's normal for large mines on Earth to cost billions of dollars, and what one can do with a large mine on Earth one could do with a vastly smaller mine on a NEO due to the superb mineral concentrations on some of them. There are a number of peer-reviewed papers putting forth that it could work out to be economical (I was reading one from the USGS just the other day) as a result of this.
But time will tell. It's going to take a lot more basic research and engineering before we can get a good sense of just what it would cost to get what sort of throughput of what sort of minerals.
As usual, "pop science" news overstated the case. We know that there's ppm quantities of water in most lunar regolith, but that's not what people usually talk about. There's also a good degree of confidence that there's a lot of *hydroxyl* group in a lot of places on the moon. But the connection between that and the group being specifically water is much weaker - and many missions sent to detect water in likely areas have failed. The best evidence for water have come from Chandrayaan and LRO, examining craters that were considered likely to find ice. They have both failed to find "slabs" of ice in the crater, but found evidence for ice grains in the regolith - about 5% according to LRO. On Earth that would be considered dry soil, but it's something at least.
Of course, if you're constraining yourself to such craters, you're really constraining where you can go. On the general lunar surface, the sun bakes water out of the regolith.
They're all tightly locked up as oxides, without the raw materials that we use to refine them on Earth being available. There are however tiny grains of raw iron in the regolith, so there is some potential to comb it out magnetically. Still, asteroids present by far better resource options in much greater concentrations.
There really is just no reason to do your work in a gravity well as deep as the moon's, and then have to break out of it, when you can just mine NEOs. Yes, it's "half the gravity of Mars", but it's vastly more than asteroids. Rockets with a couple thousand spare m/s delta-V don't just grow on lunar trees.