Delivering to Earth

[aero]

Yes, I've read about the Navy's rail gun. They must have made significant break throughs since I read about the mass driver propulsion unit. However, you should note that 5 600 mile/hour (mph) = 2.503 424 kilometer/second. That is, it is still a little weak, but surely not very long. You still have the power problem though.

[FinalFrontier]

Sure, but you're probably want to wrap the valuable metal in the cheaper stuff. Especially if you are thinking terminal velocity is sufficient braking for landing.. on land?

It depends on the cost trades.  Losing some metal due to entry may be cheaper than setting up and operating another "product line" to produce and encase the metal in "cheaper" stuff.

Boy, I don't know man.... We're talking gold bars here. Just launching them through the atmosphere? It just seems crazy!

What's wrong with simply sending it down on a Skylon or something?

Skylon does not exist yet. IT also is not designed to operate beyond LEO.

It also requires propellant like any other rocket for anything besides atmospheric operations. Meaning it would just be a very expensive and heavy ornament for deep space transportation. Velocities from the sent object heading to earth would be wrong vs. skylon orbital velocities so that rules a rendezvous/capture out.

No one is suggesting sending a Skylon to the Moon. Obviously, any gold bars would have to be transported from Lunar surface to LEO on a separate system where it could rendezvous with the Skylon or an X-37C or whatever. If the gold were to be recovered from the polar cold traps, more than enough rocket propellant could be extracted as a byproduct of the gold mining operation to power a reusable lander/reusable space tug to LEO and back. The propellant would essentially be for free: since some must be produced anyway, the marginal cost to produce 10x more than the minimum necessary is tiny compared to the initial investment.

But if one really wanted to be stingy with the propellant, IMO it would be better to aim the mass driver at L2, where it could be collected by a catcher spacecraft for very little delta v, and then delivered to LEO. There actually have been some proposals for sending winged vehicles to Lunar orbit. Whether such craft could do a direct reentry to Earth surface is beyond my paygrade to answer, however.

Thanks for clarifying I was under the impression you were suggesting sending a skylon spacecraft to the moon and back (verbatim as currently designed).

Not against sending winged vehicles BEO at all, although benefit would have to be weighed against the extra weight and debris risk.

As far as direct reentry that of course would depend on the heat shield and/or whether the vehicle could preform retro breaking.

[Warren Platts]

What's wrong with simply sending it down on a Skylon or something?

Skylon does not exist yet. IT also is not designed to operate beyond LEO. 

No one is suggesting sending a Skylon to the Moon. Obviously, any gold bars would have to be transported from Lunar surface to LEO on a separate system where it could rendezvous with the Skylon. The propellant would essentially be for free: since some must be produced anyway.

I have no idea why we are still talking about Skylon.  Now I see your mentioning reusable tugs.

The question is why? 

The mass driver concept is so ridiculously simple.  You put what you want inside a projectile.  You load it into the driver.  Then you point and you shoot.   So simple that Newton and H.G. Wells envisioned space travel with them.

Its not a matter of whether you could break even with a system that uses something like Skylon or not.  The method that will be chosen is the one that is cheapest.  There is no way I can see Skylon or any other of the recently proposed systems that require vehicles and propellant to have any chance of competing economically with a mass driver.

You keep forgetting that you're not in fact shooting dumb "slugs", as if you could simply poor molten gold into a mold as if you were making .50 caliber shot for a muzzle-loader. In fact, each "slug" would be a sophisticated spacecraft in itself that would have to manufactured on the Moon.

Take the Navy railgun example. Basically, they're shooting 20 kg guided projectiles at 2.5 km/sec. The latter velocity is just about enough to launch straight to Earth from the Moon, so they got that covered, I admit. But consider the launch rate: if you want to send back 1,000 mT of Au in one year, the gun would have to be fired 50,000 times per year, or 137 times per day (about 1 every 10 minutes). If the trip takes 10 days, that's a stream of 1,370 projectiles in space at any given moment.

Of course the Earth is constantly rotating, so you're shooting at a moving target. You will have to have a system of several target zones that ring the Earth, or else do a single, rapid-fire sequence (if you could fire the gun every 30 seconds, you could shoot off the daily quota in an hour) once per day.

Then there's the guidance systems. What are those going to need at a minimum? Probably at least a computer, a GPS, a radio system and antenna, so it can communicate, a reaction mass propulsion system, rocket nozzles, etc. These would most likely have to be imported from Earth. Assume they massed only 1 kg each: still, you're looking at $10K/kg for manufacturing costs and another $10K/kg for delivery costs, thus, $20K x 50,000 units = $1B/year. Not a deal breaker, since 1000 mT Au = $50B/year, but still, we're looking at 2% transpo costs before the guided projectiles are even assembled.

The assembly plant itself will be a sophisticated factory that will be assembling actual spacecraft running 3 shifts and pumping them out 1 every 10 minutes. Thus the mass for the railgun is actually dwarfed by the infrastructure behind it. It's the tip of a big iceberg.

In sum, the "simple slug" concept turns into a logistical nightmare when you look at the details.

Meanwhile, what would a conventional system look like?

First of all, the gold wouldn't have to be manufactured into spacecraft: it could literally be poured into molds to make conventional gold bars, a relatively simple process that could largely be automated.

The bars would then be loaded onto pallets and shipped in 30 mT batches. The space craft would have to launched at the rate of about 1 every 10 days--almost slow enough that a single, reusable lander could make the round trip, but you'd probably want a small fleet of 3 or 4 of them. These would rendezvous with the Skylon in LEO; the cargo would transferred, and then land conventionally at Heathrow. A couple of armored cars would be waiting on the tarmac, and the gold bars would be delivered straight to the vault.

Thus the expensive ground infrastructure required under the railgun solution is entirely avoided: no need for a team of scavengers to go out and basically remine and reprocess the gold after it explodes on the ground. All this remining infrastructure would have to be charged against the shipping costs.

Sure this would take a lot of propellant. If the goal is to ship 1000 mT Au to LEO, with a reusable lander, it would probably require that at least 6000 mT LH2/LO2 just for moving the gold, plus another 4000 mT to support the mining op. But if the propellant is cheap enough, it doesn't matter. Manufacturing propellant on the Moon is going to be mandatory anyway--the railgun isn't going to get you out of that necessity. But since water and propellant are bulk commodities, the production can be scaled to any desired consumption level relatively easily. A 10,000 mT production level would require filling about 6 Olympic sized swimming pools per year. Not that much, in other words, and in any case would not require any extra mining since it would be byproduct of the gold mining process.

So yes, I agree that the shipping method will be determined by what is cheaper. However, it's not at all clear that shipping via railgun is the cheaper solution. Most likely it will be more expensive than conventional rockets even in theory. In practice, it will certainly be a much more complex ballet, and so a screw up at any point would result in delays that could be hard to bounce back from. Using conventional rockets, the pace would be much less frenetic, and thus less risky, and more likely to be able to actually deliver the goods.

[Warren Platts]

Gold: 1,337° K

The long-term plan of planetary resources is to mine water and platinum group metals. Gold isn't even a PGM. In any case you are not going to get just gold. All the other stuff like platinum is just as valuable. So just make an alloy with a high melting point and refine it on earth.

The problem with PGM's is that the market for them (@ $50K USD/kg) isn't very big--it's on the order of $10B/year. Thus even if they managed to capture 50% of the PGM market, the total gross would be less than $10B/year.

Moreover, if you're talking asteroids, the business model isn't going to be the one where they capture small asteroids and process them in high Lunar orbit: a 1000 mT metal asteroid at 100 ppm PGM's at 100% recovery efficiency only amounts to 100 kg of PGM's, that at $50K/kg only equals $5M.

Thus, to make it worth it, they need to be attacking 100,000 to 1,000,000 mT metal asteroids that are too big to bring into the Earth's sphere of influence. In other words, you'll be launching from only-god-knows-where involving extremely variable azimuths and delta v's with distances measured in 10's to 100's of millions of kilometers and times measured in months and years. In which case, Will railguns even still work? Seems unlikely.

Thus if we're talking about using railguns at all to launch metals at Planet Earth, we're pretty much limited to talking about the Moon. And if that's the case, you'll most likely be going for polar cold trap gold deposits where there are extensive deposits of gold, which--for the time being at least--are (a) more valuable than PGM's, and (b) the market for which is much larger than PGM's meaning it can absorb more Au without depressing prices too much. And if we're going for gold in polar cold traps, more than enough water will be generated as a mining byproduct to make all the propellant needed to ship the gold to Earth using conventional rockets.

There is one caveat I will admit to, however: using Lunar propellant is going to be hugely energy intensive. We're talking 20 to 30 mW at a minimum. Whereas even if you were using the railgun, you would be converting electricity directly into kinetic energy (instead of first turning it into chemical energy). Thus energy requirements would be an order of magnitude less or better by using a railgun. But as I said above, there will still be a need to manufacture some propellant, unless they can figure out how to launch manned spacecraft using railguns...

[DarkenedOne]

You keep forgetting that you're not in fact shooting dumb "slugs", as if you could simply poor molten gold into a mold as if you were making .50 caliber shot for a muzzle-loader. In fact, each "slug" would be a sophisticated spacecraft in itself that would have to manufactured on the Moon.

The whole question of unguided vs guided comes down to the question of whether or not guidance in needed.  The Navy is thinking guided rounds because they want accuracy within a few meters as I understand it.  Also for a round traveling through air there is the influence of things like wind that cannot be redetermined. 

Will guided round be necessary I do not know. 

Take the Navy railgun example. Basically, they're shooting 20 kg guided projectiles at 2.5 km/sec. The latter velocity is just about enough to launch straight to Earth from the Moon, so they got that covered, I admit. But consider the launch rate: if you want to send back 1,000 mT of Au in one year, the gun would have to be fired 50,000 times per year, or 137 times per day (about 1 every 10 minutes). If the trip takes 10 days, that's a stream of 1,370 projectiles in space at any given moment.

That is how I envisioned it.  Don't see a problem here.   

Of course the Earth is constantly rotating, so you're shooting at a moving target. You will have to have a system of several target zones that ring the Earth, or else do a single, rapid-fire sequence (if you could fire the gun every 30 seconds, you could shoot off the daily quota in an hour) once per day.

Both ways work.

Then there's the guidance systems. What are those going to need at a minimum? Probably at least a computer, a GPS, a radio system and antenna, so it can communicate, a reaction mass propulsion system, rocket nozzles, etc. These would most likely have to be imported from Earth. Assume they massed only 1 kg each: still, you're looking at $10K/kg for manufacturing costs and another $10K/kg for delivery costs, thus, $20K x 50,000 units = $1B/year. Not a deal breaker, since 1000 mT Au = $50B/year, but still, we're looking at 2% transpo costs before the guided projectiles are even assembled.

Don't see a problem here either.  Although if your operation was 1000 MT per year than you probably would get a driver that can do significantly more than 20 kg.  With payload size it is an economy of scale.

The assembly plant itself will be a sophisticated factory that will be assembling actual spacecraft running 3 shifts and pumping them out 1 every 10 minutes. Thus the mass for the railgun is actually dwarfed by the infrastructure behind it. It's the tip of a big iceberg.

Why?  The shells would come in as a few pieces tops.  All the things you talked about can be made into a single module with a payload bay if you wanted.

In sum, the "simple slug" concept turns into a logistical nightmare when you look at the details.

Its all relative. 

Meanwhile, what would a conventional system look like?

First of all, the gold wouldn't have to be manufactured into spacecraft: it could literally be poured into molds to make conventional gold bars, a relatively simple process that could largely be automated.

Melting and pouring gold is trivial.

The bars would then be loaded onto pallets and shipped in 30 mT batches. The space craft would have to launched at the rate of about 1 every 10 days--almost slow enough that a single, reusable lander could make the round trip, but you'd probably want a small fleet of 3 or 4 of them. These would rendezvous with the Skylon in LEO; the cargo would transferred, and then land conventionally at Heathrow. A couple of armored cars would be waiting on the tarmac, and the gold bars would be delivered straight to the vault.

Thus the expensive ground infrastructure required under the railgun solution is entirely avoided: no need for a team of scavengers to go out and basically remine and reprocess the gold after it explodes on the ground. All this remining infrastructure would have to be charged against the shipping costs.

Sure this would take a lot of propellant. If the goal is to ship 1000 mT Au to LEO, with a reusable lander, it would probably require that at least 6000 mT LH2/LO2 just for moving the gold, plus another 4000 mT to support the mining op. But if the propellant is cheap enough, it doesn't matter. Manufacturing propellant on the Moon is going to be mandatory anyway--the railgun isn't going to get you out of that necessity. But since water and propellant are bulk commodities, the production can be scaled to any desired consumption level relatively easily. A 10,000 mT production level would require filling about 6 Olympic sized swimming pools per year. Not that much, in other words, and in any case would not require any extra mining since it would be byproduct of the gold mining process.

So yes, I agree that the shipping method will be determined by what is cheaper. However, it's not at all clear that shipping via railgun is the cheaper solution. Most likely it will be more expensive than conventional rockets even in theory. In practice, it will certainly be a much more complex ballet, and so a screw up at any point would result in delays that could be hard to bounce back from. Using conventional rockets, the pace would be much less frenetic, and thus less risky, and more likely to be able to actually deliver the goods.

1.  We have deorbited and recovered many things, and when it is done right they come down intact and in a small area.  The spacecraft would come down intact within a certain area just like Stardust did, just like the Soyuz does, just like every thing we return to Earth.  This whole remine and reprocess thing is ridiculous.

2.  If using chemical rocket propulsion than what you are describing will take far more than a factor of 6 times the material mined. 

3.  As far as complexity and risk goes a mass driver is a single stage to Earth system whereas the system you described is a two stage to Earth system.  In fact it would probably be better if you used some low thrust high impulse system to transfer from lunar orbit to LEO, which would make it a three staged system.  In complexity mass drivers are clearly superior.  They involve no space rendezvous.  In risk they are also superior in that it is far less risky to shoot a gun than it is to launch and reenter. 

4  THe system you describe requires enormous amounts of propellant, which you so casually dismiss as being trival.  The whole point for the conception of mass drivers in the first place was to avoid the need for vast quantities of propellant.  10000 mT of propellant is not trival in space.  You must factor in where your going to get such large volumes of propellant into your solution. 

Conventional rockets can only seem superior until you factor in propellants.  Mass drivers avoid the need for propellant that is why they were considered in the first place.

[Warren Platts]

You keep forgetting that you're not in fact shooting dumb "slugs", as if you could simply poor molten gold into a mold as if you were making .50 caliber shot for a muzzle-loader. In fact, each "slug" would be a sophisticated spacecraft in itself that would have to manufactured on the Moon.

The whole question of unguided vs guided comes down to the question of whether or not guidance in needed.  The Navy is thinking guided rounds because they want accuracy within a few meters as I understand it.  Also for a round traveling through air there is the influence of things like wind that cannot be redetermined. 

Will guided rounds be necessary I do not know. 

Your target on Earth is going to be on the order of 1 arcsecond, even if you have a target of several square kilometers. Is the aiming going to be that good? I sincerely doubt it. Just look at the pictures: one of those things goes off, it looks like a 16" Might Mo round going off. Even if you've got subarcsecond pointing capability (and that's not trivial--it doesn't exist now), the vibration of launch is going to induce small errors that get magnified over the 384400 km from Earth to Moon. Some sort of station keeping and guidance in satellites is pretty much standard equipment. Clearlym, the burden of proof that some sort of guidance system is not needed is on you.

Then there's the guidance systems. What are those going to need at a minimum? Probably at least a computer, a GPS, a radio system and antenna, so it can communicate, a reaction mass propulsion system, rocket nozzles, etc. These would most likely have to be imported from Earth. Assume they massed only 1 kg each: still, you're looking at $10K/kg for manufacturing costs and another $10K/kg for delivery costs, thus, $20K x 50,000 units = $1B/year. Not a deal breaker, since 1000 mT Au = $50B/year, but still, we're looking at 2% transpo costs before the guided projectiles are even assembled.

Don't see a problem here either.  Although if your operation was 1000 MT per year than you probably would get a driver that can do significantly more than 20 kg.  With payload size it is an economy of scale.

The problem is you're no longer shooting a cheap, dumb slug: you're shooting an expensive, guided projectile. Thus, if your guided, 1-piece shells with their payload bays cost 2% of the payload, you're already in a losing proposition, since cost of Skylon could reasonably range from $1000 to $250 per kg--2% to 0.5%.

The whole point of the railgun system is that it's supposed to save money--which isn't going to be much in any case, since the cost of shipping gold using conventional rockets is less than the typical daily fluctuation in the price of gold anyway!

Meanwhile, what would a conventional system look like?

The bars would then be loaded onto pallets and shipped in 30 mT batches. The space craft would have to launched at the rate of about 1 every 10 days--almost slow enough that a single, reusable lander could make the round trip, but you'd probably want a small fleet of 3 or 4 of them. These would rendezvous with the Skylon in LEO; the cargo would transferred, and then land conventionally at Heathrow. A couple of armored cars would be waiting on the tarmac, and the gold bars would be delivered straight to the vault.

Thus the expensive ground infrastructure required under the railgun solution is entirely avoided: no need for a team of scavengers to go out and basically remine and reprocess the gold after it explodes on the ground. All this remining infrastructure would have to be charged against the shipping costs.

Sure this would take a lot of propellant. If the goal is to ship 1000 mT Au to LEO, with a reusable lander, it would probably require that at least 6000 mT LH2/LO2 just for moving the gold, plus another 4000 mT to support the mining op. But if the propellant is cheap enough, it doesn't matter. Manufacturing propellant on the Moon is going to be mandatory anyway--the railgun isn't going to get you out of that necessity. But since water and propellant are bulk commodities, the production can be scaled to any desired consumption level relatively easily. A 10,000 mT production level would require filling about 6 Olympic sized swimming pools per year. Not that much, in other words, and in any case would not require any extra mining since it would be byproduct of the gold mining process.

So yes, I agree that the shipping method will be determined by what is cheaper. However, it's not at all clear that shipping via railgun is the cheaper solution. Most likely it will be more expensive than conventional rockets even in theory. In practice, it will certainly be a much more complex ballet, and so a screw up at any point would result in delays that could be hard to bounce back from. Using conventional rockets, the pace would be much less frenetic, and thus less risky, and more likely to be able to actually deliver the goods.

1.  We have deorbited and recovered many things, and when it is done right they come down intact and in a small area.  The spacecraft would come down intact within a certain area just like Stardust did, just like the Soyuz does, just like every thing we return to Earth.  This whole remine and reprocess thing is ridiculous.

I thought you wanted to shoot dumb slugs and crash land them on Earth at supersonic speeds. You do this, then you are definitely in the remining and rerefining business. Soyuz and Stardust both have guidance systems and parachutes. I wouldn't blame you for choosing this route though. These won't be cheap, however.

2.  If using chemical rocket propulsion than what you are describing will take far more than a factor of 6 times the material mined. 

No, that's about right. If anything, that's a conservative estimate that doesn't take into account aerobraking. If aerobraking were used it would be more like 2000 mT to send it to Earth. But, like I keep saying, if your propellant cost is nearly free, it doesn't matter whether you 2000 or 6000 tonnes to ship the 1000 tonnes.

3.  As far as complexity and risk goes a mass driver is a single stage to Earth system whereas the system you described is a two stage to Earth system.  In fact it would probably be better if you used some low thrust high impulse system to transfer from lunar orbit to LEO, which would make it a three staged system.  In complexity mass drivers are clearly superior.  They involve no space rendezvous.  In risk they are also superior in that it is far less risky to shoot a gun than it is to launch and reenter.

The transfer to the Skylon won't be a big deal. The gold would be in a single container. Using Skylon (or something like an X-37C) would be simpler since it would involve far fewer actual flights, and the product would be ready for the vault once it's landed.

4  THe system you describe requires enormous amounts of propellant, which you so casually dismiss as being trival.  The whole point for the conception of mass drivers in the first place was to avoid the need for vast quantities of propellant.  10000 mT of propellant is not trival in space.  You must factor in where your going to get such large volumes of propellant into your solution.  Conventional rockets can only seem superior until you factor in propellants.   

I already explained where the propellant if going to come from: it's a byproduct of the gold mining process. Even if the Au concentration were an unheard of 1000 ppm and the water content only 6%, 1,000,000 mT of regolith would have to excavated which could be expected to produce around 60,000 mT of H20 that could in turn produce up to 40,000 mT of LH2/LO2 (mass ratio 5). If the mine was set up using ACES-style landers, there would be a ready made tank farm capable of holding 1000 or more mT of LH2/LO2. Any given launch would only use between 40 and 70 mT of propellant at any given time.

Your aversion to the propellant thing is powered by mere intuition. When you look at the actual numbers, it stacks up quite nicely. Cost projections of $100/kg or less at Lunar surface are quite reasonable. Thus, using aerobraking and Skylon the shipping cost per kg from Lunar surface to Earth surface could reasonably get down to $500/kg, which is 1% of the price of gold. Given that, why even bother with mass drivers?

[RanulfC]

Backing up to the OP, delivering stuff to Earth, if you ever want to have a market for this tether sending stuff up and down, you might want to consider supporting my, ahem, modest proposal to put 100k humans on the Moon in forty years.

You scratch my project, and I'll scratch yours, or something.

Well, that's actually a good basis/rationale/reason for an extended tether transport system since it emplaces a lot of infrastructure in Earth-Luna space

They "system" CAN be "propellantless" as long as traffic down and up are pretty well matched. Taking people and equipment up and returning materials to Earth would do that...

Randy

[rklaehn]

Gold: 1,337° K

The long-term plan of planetary resources is to mine water and platinum group metals. Gold isn't even a PGM. In any case you are not going to get just gold. All the other stuff like platinum is just as valuable. So just make an alloy with a high melting point and refine it on earth.

The problem with PGM's is that the market for them (@ $50K USD/kg) isn't very big--it's on the order of $10B/year. Thus even if they managed to capture 50% of the PGM market, the total gross would be less than $10B/year.

Given that PGM are tremendously useful in all sorts of applications, I would think that the world market would expand significantly if you could get the price down a bit.

Moreover, if you're talking asteroids, the business model isn't going to be the one where they capture small asteroids and process them in high Lunar orbit: a 1000 mT metal asteroid at 100 ppm PGM's at 100% recovery efficiency only amounts to 100 kg of PGM's, that at $50K/kg only equals $5M.

Thus, to make it worth it, they need to be attacking 100,000 to 1,000,000 mT metal asteroids that are too big to bring into the Earth's sphere of influence. In other words, you'll be launching from only-god-knows-where involving extremely variable azimuths and delta v's with distances measured in 10's to 100's of millions of kilometers and times measured in months and years. In which case, Will railguns even still work? Seems unlikely.

I think the railgun idea is not too well tought out in the first place. Sticking a tether to the source asteroid and exploiting its angular momentum to accelerate the payloads would make much more sense.

And why should it matter how far away the asteroid is as long as you can give the payload the required delta-v with the required precision.

Thus if we're talking about using railguns at all to launch metals at Planet Earth, we're pretty much limited to talking about the Moon. And if that's the case, you'll most likely be going for polar cold trap gold deposits where there are extensive deposits of gold, which--for the time being at least--are (a) more valuable than PGM's, and (b) the market for which is much larger than PGM's meaning it can absorb more Au without depressing prices too much. And if we're going for gold in polar cold traps, more than enough water will be generated as a mining byproduct to make all the propellant needed to ship the gold to Earth using conventional rockets.

You can use a rotating tether to launch payloads from the moon as well. There was a thread about the concept a while ago. Makes much more sense than a railgun. Nobody has ever built a railgun that doesn't need to be rebuilt after a trivial number of shots (<100). Or are people using railgun as a generic name for an electromagnetic accelerator now?

[RanulfC]

The [ahem... 3,000,000 kg] tether station is actually the key piece.

Apoligies, but I won't be able to get to those links for a couple weeks.  I assume 3000 tonnes would need to be all one piece?  Or can a couple of splices break that up?

It can be broken up into modular sections as needed. In fact it can "bootstrap" sections of itself during construction as it goes. 
 
Randy

[RanulfC]

You can use a rotating tether to launch payloads from the moon as well. There was a thread about the concept a while ago. Makes much more sense than a railgun. Nobody has ever built a railgun that doesn't need to be rebuilt after a trivial number of shots (<100). Or are people using railgun as a generic name for an electromagnetic accelerator now?

Pretty much

The more correct term for the concept would probably be "coil-gun" rather than rail-gun but what they are talking about it an accelerator that does NOT tear its guts up every other shot

The thread on slinging stuff from the Moon is title (appropriatly of course ) "Sling stuff FROM the Moon..."

And can be found here: http://forum.nasaspaceflight.com/index.php?topic=5420.0;all

Randy

[Warren Platts]

Gold: 1,337° K

The long-term plan of planetary resources is to mine water and platinum group metals. Gold isn't even a PGM. In any case you are not going to get just gold. All the other stuff like platinum is just as valuable. So just make an alloy with a high melting point and refine it on earth.

The problem with PGM's is that the market for them (@ $50K USD/kg) isn't very big--it's on the order of $10B/year. Thus even if they managed to capture 50% of the PGM market, the total gross would be less than $10B/year.

Given that PGM are tremendously useful in all sorts of applications, I would think that the world market would expand significantly if you could get the price down a bit.

I agree 100%. But if PGM's are only worth $20/kg, they are not going to be worth importing back to Earth.

[gbaikie]

Gold: 1,337° K

The long-term plan of planetary resources is to mine water and platinum group metals. Gold isn't even a PGM. In any case you are not going to get just gold. All the other stuff like platinum is just as valuable. So just make an alloy with a high melting point and refine it on earth.

The problem with PGM's is that the market for them (@ $50K USD/kg) isn't very big--it's on the order of $10B/year. Thus even if they managed to capture 50% of the PGM market, the total gross would be less than $10B/year.

Given that PGM are tremendously useful in all sorts of applications, I would think that the world market would expand significantly if you could get the price down a bit.

I agree 100%. But if PGM's are only worth $20/kg, they are not going to be worth importing back to Earth.

I think you confusing rare earths with PGM.

"The six platinum group metals are ruthenium, rhodium, palladium, osmium, iridium, and platinum."
http://en.wikipedia.org/wiki/Platinum_group

Ru: Ruthenium: "The metal is priced at about $30/gram"
http://www.radiochemistry.org/periodictable/elements/44.html
Rh: Rhodium: Rhodium costs about $1,000/troy oz.
Pd: PALLADIUM: The metal sells for about $150/troy oz.
Os: OSMIUM:"The price of 99% pure osmium powder - the form usually supplied commercially - is about $100/g"
Ir: IRIDIUM: Iridium costs about $500/troy ounce (as of 1990)
Pt: PLATINUM: The price of platinum has varied widely. More than a century ago platinum was used to adulterate gold and was worth nearly eight times more than gold in 1920. The price in January 1990 was about $500/troy oz

All from: http://www.radiochemistry.org/periodictable/index.shtml

[Warren Platts]

Gold: 1,337° K

The long-term plan of planetary resources is to mine water and platinum group metals. Gold isn't even a PGM. In any case you are not going to get just gold. All the other stuff like platinum is just as valuable. So just make an alloy with a high melting point and refine it on earth.

The problem with PGM's is that the market for them (@ $50K USD/kg) isn't very big--it's on the order of $10B/year. Thus even if they managed to capture 50% of the PGM market, the total gross would be less than $10B/year.

Given that PGM are tremendously useful in all sorts of applications, I would think that the world market would expand significantly if you could get the price down a bit.

I agree 100%. But if PGM's are only worth $20/kg, they are not going to be worth importing back to Earth.

I think you confusing rare earths with PGM.

"The six platinum group metals are ruthenium, rhodium, palladium, osmium, iridium, and platinum."
http://en.wikipedia.org/wiki/Platinum_group

Ru: Ruthenium: "The metal is priced at about $30/gram"
http://www.radiochemistry.org/periodictable/elements/44.html
Rh: Rhodium: Rhodium costs about $1,000/troy oz.
Pd: PALLADIUM: The metal sells for about $150/troy oz.
Os: OSMIUM:"The price of 99% pure osmium powder - the form usually supplied commercially - is about $100/g"
Ir: IRIDIUM: Iridium costs about $500/troy ounce (as of 1990)
Pt: PLATINUM: The price of platinum has varied widely. More than a century ago platinum was used to adulterate gold and was worth nearly eight times more than gold in 1920. The price in January 1990 was about $500/troy oz

All from: http://www.radiochemistry.org/periodictable/index.shtml

I'm aware of the price of PGM's now. If you want PGM coins, this is the place to go:

http://www.americanelements.com/

The point is the high mining, processing, refining, and transportation costs involved in space mining sets a floor or minimum price that any space commodity must command in order to break even. With the technology foreseeable in the near future (and this even includes sling-a-trons), my best guess is that anything less than 1 to 10 $K/kg will not be profitable.

So, sure the demand for PGM's would increase at a lot if you could get the price down to $1K/kg, but all you'll wind up doing is putting yourself out of business. This happens all the time in the minerals industry: cf., dry natural gas producers in the USA.

Thus, it would be desirable for a mining company to have a monopoly on Lunar mining. Unfortunately, under the OST, it'll be a free-for-all, unless the companies get together and form an OPEC-like cartel and voluntarily restrict production in order to keep prices propped up.

[Archer]

Are warheads of nuclear missiles (ICBM) guided during their descent?
They are very accurate.

[RanulfC]

As a thought of a way to move payloads off the Lunar surface this might be a consideration:
http://ntrs.nasa.gov/search.jsp?R=20030018907

Randy