Ares and Ares

neviden · 2006-09-12 09:28:20

there is nothing inherently wrong with a concept of asteoroid mining
But there is! So many people are totally infatuated with the low delta requirements that they refuse to accept the simple truth that the devil really is in the details!

The devil might lay in the details, but there is nothing that could not be solved with simple solutions..

First this crazy notion of spinning anything the size of a mining refinery is pretty silly

What is so crazy about making cylindrical object spin around it's axis by firing thrusters? bigger only means more propelant, but once it's spinning it will go on spinning forever and you will not need any more propelant.. and since the point of this spinning will to make 1G the stress on rafinery is the same as you would have on earth.. because, that's the point of the spin...

, the difficulty of docking with it in the first place rules that out pretty much. You can't have spinning and non-spinning sections really due to the unavoidable friction between the two parts.

yes, it would be very dificult to dock with a spinning station, but there are two points where you can atach spinning and non-spinning parts.. by.. hmm.. how do we manage to keep tires on moving cars? I hardly think nobody can develop ball bearings (to use the simplest method known) that will last for loong time.. and if something goes wrong, you can break off connection, fix, and redock..

The size and mass you would need is quite extreme, especially with some 2001 ring station docking bay arrangement, which is pretty much the only option. Definatly not a project for this half of the century.

"size and massis is quite extreme" = "useless material that is left"..

small autonomus ships with big grapple like that used in moving scrap metals around on earth.. "land" on the asteroid, grab onto rock and see what happends... If the rocks are made of gravel, then you only need to grab it with a grapple... if you do not dislodge a rock, then you are on the asteorid and you can start to drill
No! You are still thinking like you are on a body with gravity: a digging scoop or a grapple requires force to penitrate into the ground in order to get the digging implement around the dirt, which you don't have! The grapple will not even penitrate the ground!

Scrap metals gets picked up with things like that .. they dangle in air and close to grab things.. there is no need for gravity or outside force to grab pieces lying around.. you would have to target things that are sticking from the "surface" and then use force to close scoop.. if you slip just reopen them, and try again.. there is no need to digg in if material is this loose..

The same thing with a drill, it doesn't matter what the asteroid is made of, a drill can't bite into the surface without downward force; thats the way drills operate, they use the downward force to scrape up the dirt or whatever with it sharpend ends. Press the drill against the rock, and the only thing that gets dislodged is the drill, which gets pushed back into the air. Go swimming, and try to push the bottom of the swimming pool, and the only thing that happens is you get pushed tward the surface.

if you grab onto some rock you can use it for leverage for drill.. in that case you either manage to drill into rock (if it is solid and strong enough) or you brake off your anchorage point.. either case you get material you need.. and this would defentitly work in a swimming pool..

You will not suceeed with either method, because both these tools and all purely mechanical tools rely on applied force, and thanks to Newton's law the only thing you would accomplish is to push yourself back into space. You will get no material at all beyond whatever pebbles are sitting on the surface. This is why you would need some kind of rocket-driven anchor system.

there is no need to get anything more than pebbles, if you can get many tons of them.. just repeat untill you have enough of them..

And there is worthless materal; what if the rock you are digging is 90% junk and 10% water? That means its only ~1% hydrogen, the fuel of choice for reuseable nuclear vehicles. It would require such a huge digging operation that it really may not be worthwhile to mine the asteroid, ever.

why bother with nuclear with 1000s isp and only H2, if you already have H2 and O2 from water that wil give you 450s ips.. and you have more than enough sunlight to process water into propelant and refuel spaceship..

Which leads me to reiterate my last point, which you totally missed: that if you have to go through all this titanic trouble to dig up 1kg of fuel from an asteroid, who cares if you are saving 9kg by not having to launch it from Earth or Mars'es surface? Rocket fuel is rocket fuel, there is nothing magic or special about what you dig out of an asteroid. So, its just so much easier to crack Florida tap water or blocks of Martian polar ice or shovel the omnipresent Lunar dirt into a furnace in vast quantities, it doesn't matter that you'll burn 90% of it to deliver it, its still far cheaper!

why do this? because if you don't have to send everything from earth, you can send only what you DO need.. there is no way you can build 10.000 MT spaceship on earth and send it to LEO.. but if you can get unlimited propelant, structural materials and such simple things in space, then you only need to send the complicated things.. so that 10.000 MT spaceship becomes 9.500 MT spaceship made from material from space and propelant to get it somewhere and 500 MT electronics and complicated things sent from earth..

and we will need 10.000 MT spaceships if we wan't to send more than few people to mars..

Just add RLV and stir. It can't possibly be any harder to build than such a mining operation.

RLV just lower costs.. it doesn't return any money just because it is RLV.. mining operation enables you to build large things in space that can enable you to extract something (gold?) to be sold on earth.. to pay those RLV..

GCNRevenger · 2006-09-12 09:51:23

No, I said that a way to gain competance in a particular skill was by trying; there are plenty of things that we can predict that trying will yeild little or no bennefit. Asteroid mining is one of these, that all the methods used to accomplish the mining will have to exert force on the asteroid, we know this from highschool physics, but thanks to Newton there isn't an efficient way to do this. There is just not, the only way to exert force is by using a rocket, which is not going to do, or else string thousands of kilometers of wire around the thing. Can it be done this way? Sure, but we know that it can't be done efficiently, and so the penalty of launching easy-to-get reasources from Earth/Moon/Mars is less than the penalty of trying to dig rocks. Scale is everything, that it will just be easier to increase the scale of a Earth/Moon/Mars fuel factory & launch system despite burning most of it for launch.

neviden · 2006-09-12 10:10:16

there are plenty of things that we can predict that trying will yeild little or no bennefit. Asteroid mining is one of these,

Unimited amount of propelant in mars orbit seems like a nice bennefit..

more propelant = more delta-v = faster travel = safer travel
more propelant = bigger ship = safer travel
more propelant = no need to send propelant from earth = cheaper travel
more propelant = bigger cheaper ship (use bigger cheaper things) = cheaper travel
more propelant = send to LEO = money, cheaper travel

that all the methods used to accomplish the mining will have to exert force on the asteroid, we know this from highschool physics, but thanks to Newton there isn't an efficient way to do this.

I proposed simple way that is not limited by mass.. it's not hard, it does not violate any laws.. and your response is "lalalalala.. I know you are wrong.."..

Tom Kalbfus · 2006-09-12 10:40:24

No, I said that a way to gain competance in a particular skill was by trying; there are plenty of things that we can predict that trying will yeild little or no bennefit. Asteroid mining is one of these, that all the methods used to accomplish the mining will have to exert force on the asteroid, we know this from highschool physics, but thanks to Newton there isn't an efficient way to do this. There is just not, the only way to exert force is by using a rocket, which is not going to do, or else string thousands of kilometers of wire around the thing. Can it be done this way? Sure, but we know that it can't be done efficiently, and so the penalty of launching easy-to-get reasources from Earth/Moon/Mars is less than the penalty of trying to dig rocks. Scale is everything, that it will just be easier to increase the scale of a Earth/Moon/Mars fuel factory & launch system despite burning most of it for launch.

I get a sense that you don't really want asteroid mining to work because it will interfere with your other ideas or so you think. I don't know why you think so. if I put my engineers hat on we still have inertia to work against in drilling against an asteroid. If you place a 1 ton drill on the surface of Phobos with the drill bit pointing downward, that drill doesn't weigh much against Phobos' gravity, but if the drill presses down to bite against the Phobos surface, it will also be pushing up against 1 ton of machinery. if the drill can extend outward while pushing into the surface and drilling and if it can get a sufficient hold onto Phobos surface by drilling downward far enough before the machinery lifts off the surface beyond the distance of the extended drill bit, the solidity of Phobo's surface will prevent the machinery from rising further and it will hold it fast. And by using the rocky surface of Phobos as an anchor, you can drill more drill bits into the surface and further secure the mining rigs grip on the moon. And once you have a fairly secure anchorage into the Moon's surface you can drill with very large drill bits down to significant depths and get out lots of material. We've never done this before, but it looks like you are afraid to think outside the box like it says at the bottom of your posts. Sometimes however thinking outside the box is what's called for, its called invention. If we are going to mine the asteroids we have to invent a new process, its as simple as that. Avoiding mining the asteroids and mining Mars instead because their is a gravity well to work against and we know how to mine in those conditions is just silly. Inventing a new mining process is only a little trouble, I'm sure some clever person can figure it out, maybe you don't want to , but I bet there is someone else who is willing to give it a try. We should start with probes to the asteroids and phobos, the simple sample return mission. If we can retrieve some samples from an asteroid we simply have to scale up the process and we have an asteroid mining operation.

noosfractal · 2006-09-12 20:24:38

No! You are still thinking like you are on a body with gravity: a digging scoop or a grapple requires force to penitrate into the ground in order to get the digging implement around the dirt, which you don't have! The grapple will not even penitrate the ground!

What about using the momentum of ejected ore to keep the drill bit against the asteroid surface?

I'm imagining a drill bit like this ...

only larger, and perhaps more spinning bits around the edge of the torus. The spinning bits would direct the ore through the center of the torus and then there would be further spinning cylinders (perhaps plastic-coated or the like) inside a tube whose role is to accelerate the ore towards a waiting orbiter. The ore stream would then be caught in a net or bag and eventually towed back to Earth. I really don't see onsite refining at first.

dicktice · 2006-09-13 08:24:22

Ingenious, and capable of being proven on the air-cusion floor used to develop the Canadarms.

GCNRevenger · 2006-09-13 08:59:07

The devil might lay in the details, but there is nothing that could not be solved with simple solutions..

There are lots of things that don't have simple solutions, jet turbines, computer chip arcitectures, etc. Some things just aren't simple.

What is so crazy about making cylindrical object spin around it's axis by firing thrusters? bigger only means more propelant

Scale and docking. First off, the scale of propellant needed to spin something that big must be substantial, and will be a signifigant startup cost since you'd have to import the fuel before the refinery could be started up. Plus, when you add or remove material from the station, more propellant would have to be expended to spin up or spin down the gain or loss of mass.

You can't have spinning and non-spinning sections, since the friction of the bearing between them is nonzero, so the spinning section will pass off momentum to the non-spinning section. Unless you burn propellant constantly to counteract this. Starting to see a trend here? Alot of little propellant penalties for very big/heavy stations adds up to a serious decrease in efficiency. How much of the propellant you dig up will have to be burned for stationkeeping versus used to lift off Earth/Moon/Mars?

"size and massis is quite extreme" = "useless material that is left"..

Chicken and egg, you have to build a refinery to make metals or composites so you can build the refinery? Plus, if you want to build it of metal, asteroids with carbon and water generally have very little metal and vice versa. So you would have to build the refinery elsewhere and ship it to the asteroid at great expense.

there is no need for gravity or outside force to grab pieces lying around.. you would have to target things that are sticking from the "surface" and then use force to close scoop.. if you slip just reopen them, and try again.. there is no need to digg in if material is this loose

Wrong, you still need an anchor against the surface or else burn rocket fuel to maneuver the grapple, plus this hinges on useful material literally sitting on the surface as convienant chunks: this is silly, since if it is a light element asteroid all the useful volitiles (esp. water) will have boiled off long ago from surface rocks, and metal rich asteroids are more solid chunks of melted metal back when the solar system was hot. And even if this were not the case, asteroids of decent size like Phobos are coverd in a thick layer of dust like the Moon, which you can't dig up without down force. Try to use the grapple on it, and you'll dig up nothing.

And say you pull the surface rocks off to get the material under it? You'll have to move an awful lot of rock, and even once you have done that the underlying material will be more compacted anyway, so again the grapple nor a drill would do you a bit of good. I imagine you woud have to dig down fairly deeply to get at volitiles too, so how do you prevent the hole from collapsing?

why bother with nuclear with 1000s isp and only H2

I'm not talking whimpy solid-core nuclear rockets, but rather 3000-10,000sec advanced nuclear engines. With such power, even throwing away all the oxygen is still better, Hydrogen would still be preferred.

so that 10.000 MT spaceship becomes 9.500 MT spaceship made from material from space and propelant to get it somewhere and 500 MT electronics and complicated things sent from earth..

But all the trouble to mine the reasources, refine the materials, fabricate the components, and maintain all that, and carry the remaining crew & payloads to the shipyard... is that really easier? Is that really better?

The trouble of maintaining such an operation, what if it takes 100's of tonnes of supplies to run such an outfit and the cost of it all, how can that compete against just increasing what you launch from Earth by an order of magnetude? With reuseable launch vehicles their cost goes down as flights go up substantially, so they will still be cheaper because its so much easier to build right here.

mining operation enables you to build large things in space

You can build large things in LEO too, except mine & refine everything on the ground, fabricate the parts, and only assemble them in orbit.

that can enable you to extract something (gold?) to be sold on earth

All trivial compared to the cost of colonization frankly. And why wouldn't you just mine the metals on the Moon? They have plenty of asteroids on the surface, and are right next door to their target market. You can even build a Lunar space elevator in theory with today's materials (Kevlar, Spectra).

GCNRevenger · 2006-09-13 09:02:51

Unimited amount of propelant in mars orbit seems like a nice bennefit..

There is unlimited propellant sitting on the Martian polar caps and floating in its atmosphere, perhaps underground as permafrost too. This is so much easier to dig up, it will be better and cheaper than trying to dig an asteroid in zero-G, despite having to burn most of it to launch it.

So no, no more propellant

it's not hard, it does not violate any laws

But it does! Unless the materials you want are nice convienant chunks sitting on the surface, which isn't going to happen.

GCNRevenger · 2006-09-13 09:24:54

I get a sense that you don't really want asteroid mining to work because it will interfere with your other ideas or so you think.

Ah yes, because I don't parrot the "asteroid mining = good" dogma, I must have a hidden, alterior, manipulative, Maciavellian agenda!

but if the drill presses down to bite against the Phobos surface, it will also be pushing up against 1 ton of machinery... the solidity of Phobo's surface will prevent the machinery from rising further and it will hold it fast

Heh yeah, except your drill rig will also spin in circles as soon as the drill bit gains traction with the surface... There is still a substantial amount of force needed to get a drill bit to even start, and I have doubts that just inertia would be enough. Even if it were however, you'll need alot of propellant to push around the drill rig. How efficient is that?

its called invention

Invention does not nessesarrily require radical thinking.

Avoiding mining the asteroids and mining Mars instead because their is a gravity well to work against and we know how to mine in those conditions is just silly. Inventing a new mining process is only a little trouble

No no, its all about efficiency, sure there are ways you can dig asteroids, but is it efficient to do so? On Mars all you have to do is cut blocks of polar glaciers and stick that into your solar/nuclear thermolosys rig, or shovel Lunar dust into a furnace, or crack Florida tap water on Earth. The point being, that its so easy to do it on the ground, that asteroid mining can't compete since its so hard despite the gravity well.

I am however saying that asteroid mining is never going to be as easy as surface mining; the challenges of working basically free-floating in space are such that there is no such thing as a simple, cheap solution. Therefore, with the advent of RLVs, it is reasonable to question if asteroid mining will ever be a good idea. We don't mine the ocean floor for minerals on Earth, yet there is a great deal down there, for the same reason.

If we can retrieve some samples from an asteroid we simply have to scale up the process and we have an asteroid mining operation

Nonsense, what works for a few grams of dust and rock may not and probably won't be good enough for mass quantities. Especially trying to chase veins of water ice deep through coal-like carbonacious asteroids.

GCNRevenger · 2006-09-13 09:30:10

What about using the momentum of ejected ore to keep the drill bit against the asteroid surface?
The ore stream would then be caught in a net or bag and eventually towed back to Earth. I really don't see onsite refining at first.

That would take an awful lot of power to exert the thrusts required to make such a drill work, nor would it provide the initial thrust required to start the drilling shaft.

And, if you capture the rock and dust, won't that blow the orbiter into space with similar thrust? "Whoops"

Edit: The recieving orbiter vehicle would need to burn as much rocket fuel as your drill would need to just push down with a rocket. No where near efficient enough.

Then you have the problem of the valuble water ice and other volitiles boiling off now that you've so convienantly crushed the ore and thrown it into space, to be captured in a big open-to-vacuum bag, probably exposed to the sunlight too.

And this kind of drill probably won't work with a nearly solid metal asteroid if you are wanting to harvest metals.

I really don't see onsite refining at first.

Pobably not, but what about the water and other volitiles?

Tom Kalbfus · 2006-09-13 13:33:41

I get a sense that you don't really want asteroid mining to work because it will interfere with your other ideas or so you think.
Ah yes, because I don't parrot the "asteroid mining = good" dogma, I must have a hidden, alterior, manipulative, Maciavellian agenda!
but if the drill presses down to bite against the Phobos surface, it will also be pushing up against 1 ton of machinery... the solidity of Phobo's surface will prevent the machinery from rising further and it will hold it fast
Heh yeah, except your drill rig will also spin in circles as soon as the drill bit gains traction with the surface... There is still a substantial amount of force needed to get a drill bit to even start, and I have doubts that just inertia would be enough. Even if it were however, you'll need alot of propellant to push around the drill rig. How efficient is that?

I believe NASA solved that problem during the Gemini program, they invented tools for working in space, one such was a drill with a counter rotation ring, that way it didn't spin the astronaut. Larger counter rotation rings would no doubt work. its not that I'm an engineer or something, but sometimes you sound like your saying, "Oh here's a problem we have to deal with, lets give up, there's no way anyone's going to solve it!" I bet you their is an engineer who upon reading that sentence is going to say, "what do you mean I can't solve it?" Breaking the light barrier, building starships, finding a cure for old age, and mining the asteroids are all at the same level of difficulty. In each of these endeavours you are going to encounter problems. if you say, "This has never been done, I give up the problem won't be solved by you. I may not be an engineer, but I think I have enough of an intuitive grasp to realize that mining the asteroids is not as hard as finging a way of traveling at 50% of the speed of light. I think if we are going to settle the Solar System, we'll have to find a way to use the asteroids. Mars doesn't have that much surface area, and Interstellar travel will be extremely hard and expensive. The easiest thing to do to accomodate our expanding civilization is to build free floating space settlements, and this will require asteroids alot more than lifting material off of planets.

its called invention
Invention does not nessesarrily require radical thinking.

I guess its a matter of how far you think "outside of the box". I don't think mining the asteroids is as far outside of the box as building an antigravity machine to lift yourself off the surface of the Earth. The further you go outside the box, the more likley you are to go wrong, on the otherhand the best answer might not be inside the box, so you have to look elsewhere for it.

Ian Flint · 2006-09-14 19:06:29

I think you guys are missing GCNR's point.

Sure, for the long term, when you have already built mining ships big enough to gobble up asteroids and use every element they contain, then and only then, will asteroid mining be more efficient than planetary mining.

I'm sure that GCNR would agree that small scale asteroid mining should be experimented with, but entire colonization programs shouldn't be based on it. And, we shouldn't delude ourselves into thinking that it will become cheap anytime soon.

dicktice · 2006-09-15 08:36:51

I would like to have some discussion here regarding mining asteroids from the inside out.

SpaceNut · 2006-09-15 09:46:38

How about using high powered cutting lasers to carve of pieces that can be captured by a mesh net.

Tom Kalbfus · 2006-09-15 11:25:41

Asteroids as you know aren't perfectly smooth or round, they are filled with crevices and craters. Once you get down into the solid part of the asteroid, then you can brace yourself against one part of the asteroids to drill into another part, you don't need rockets or gravity to do that. You can have tunneling machines that grab onto the walls of the tunnels they make and the ore can be transported to the surface of the asteroid for transport elsewhere for processing.

noosfractal · 2006-09-15 14:25:47

What about using the momentum of ejected ore to keep the drill bit against the asteroid surface?
The ore stream would then be caught in a net or bag and eventually towed back to Earth. I really don't see onsite refining at first.
That would take an awful lot of power to exert the thrusts required to make such a drill work

I think the required thrust perpendicular to the surface is fairly modest for this type of drill - the deep drilling guys use this sort of drill and don't exert much force through the drilling shaft beyond its own weight. Also, as noted by Tom below, once the shaft is started, you can use tracks or the like to keep burrowing.

nor would it provide the initial thrust required to start the drilling shaft.

Right, you need thrusters to get going.

And, if you capture the rock and dust, won't that blow the orbiter into space with similar thrust? "Whoops"
Edit: The recieving orbiter vehicle would need to burn as much rocket fuel as your drill would need to just push down with a rocket. No where near efficient enough.

Two ideas here.

The first is that the orbiter will be collecting mass so that the added momentum of the ore stream will accelerate it less and less. If you don't mind that the orbiter is getting further away (it does have to return to Earth at some point after all) then you can just plan for the vector that the ore stream will add.

If that doesn't work, then perhaps it would be again possible to use ejected ore to counter the vector. I'll assume the orbiter has access to more power than the miner. If the orbiter can accelerate 1% of the received ore to 100 times the velocity of the ore stream (or 10% of the received or to 10 times the velocity, etc), then it can remain in relative position while still collecting ore.

Then you have the problem of the valuble water ice and other volitiles boiling off now that you've so convienantly crushed the ore and thrown it into space, to be captured in a big open-to-vacuum bag, probably exposed to the sunlight too.

There is sure to be some loss, but I don't think it'll be 100%. We can improve on efficiency later, I'm just trying to think of something that is cheap and will get a load of whatever is valuable. The bag may have to be more of a funnel to a collection point, particularly for volatiles.

And this kind of drill probably won't work with a nearly solid metal asteroid if you are wanting to harvest metals.

Are some really solid metals and not some sort of compound ore? Wow. No, I don't think this drill would work for that scenario. I guess it'd be brittle because of the low temperature. Maybe you could shatter it first with a shaped explosion directed through a plane some yards below the surface you want to mine. Hard to automate though.

Probably your best bet would be to blow hot CO over the metal to extract via a carbonyl, but the added complexity is horrible.

I really don't see onsite refining at first.
Pobably not, but what about the water and other volitiles?

You are probably right about the volatiles, but the refining effort isn't too bad because of the free vacuum.

noosfractal · 2006-09-15 15:04:56

I would like to have some discussion here regarding mining asteroids from the inside out.

If the asteroid rotates, then a shaft dug parallel to the surface would have a "floor" to work against due to centrifugal force.

If you were only just below the surface, you push out the "floor" from below you (or some of it anyway) and it would fly out to a waiting orbiter.

Oh, I like it - using the asteroid's own rotational energy to dismantle it.

Hey, if you attach a standard electric generator at a pole of rotation, you'll get your electrical energy for free - maybe we could use gigawatt lasers to carve it up.

Grypd · 2006-09-16 08:35:19

Assuming you are wanting volatiles then the asteroid of choice will be the NEA class of asteroid. These are believed to be 40% by class ex comets. They will still have substantial volatiles but with a crust to stop there distinctive tails forming.

To mine would be a case of attaching to the asteroid maybe with the use of a corkscrew device with an initial push to enter the crust and the screw to then dig in. From there it will be possible to snake out tendrils to heat the volatiles which will be collected and allow the tendrils to dig in further.

From there the miner will keep heating the surrounding area to create a cavern collecting the volatiles which can be collected. There will also be rock and metals in suspension inside the NEA and these can also be collected for processing elsewhere.

Some of these tendrils will ark back out and these can form further anchoring points and these will also provide tanker points where robotic tankers can collect the volatiles away to where they are wanted.

Another substantial class of asteroids is silicates and these will also be an option to be mined the same way though they will have less volatiles and more minerals in the form of nickel-irons.

dicktice · 2006-09-16 12:08:34

By "miner" I presume you mean a robotic, remote-presence machine operated in shifts by the crew of a prospecting vehicle situated near the asteroid in queastion, eh?

noosfractal · 2006-09-16 13:34:08

By "miner" I presume you mean a robotic, remote-presence machine operated in shifts by the crew of a prospecting vehicle situated near the asteroid in queastion, eh?

Yes, except that I would advocate significant expenditure to develop adequate telepresence technology (i.e., that copes with the up to an hour round trip communications time) so that the operators can be situated on Earth, and later Mars, rather than near the target asteroid. However, I do appreciate that the high level of automation required for this may not be achievable in the near future.

noosfractal · 2006-09-16 13:38:36

From there it will be possible to snake out tendrils to heat the volatiles which will be collected and allow the tendrils to dig in further.

I'm having a hard time visualizing how robotic tendrils might work. Are there any protoypes/references you could point me to that would help?

Grypd · 2006-09-16 15:15:59

In some ways I really should have said a robotic worm like the article below.

Robot Worm

They would heat there way through the volatiles leaving a cable behind in which we could put heat through and collect the melted volatiles. These would be the tendrils and some of these robotic worms could be designed to drill there way along from the miner and to make further anchor points for more miners or to create a place for automated tankers to collect melted volatiles and unrefined minerals.

By "miner" I presume you mean a robotic, remote-presence machine operated in shifts by the crew of a prospecting vehicle situated near the asteroid in queastion, eh?

Certainly we will need to have surveyed the asteroid but it does not make sense to use Human crews. It does make sense to have as much automated as possible and telepresence is quite possible as mining will be a slow process and constant attention to the devices will not be needed.

Tom Kalbfus · 2006-09-17 08:30:32

I would like to have some discussion here regarding mining asteroids from the inside out.
If the asteroid rotates, then a shaft dug parallel to the surface would have a "floor" to work against due to centrifugal force.
If you were only just below the surface, you push out the "floor" from below you (or some of it anyway) and it would fly out to a waiting orbiter.
Oh, I like it - using the asteroid's own rotational energy to dismantle it.
Hey, if you attach a standard electric generator at a pole of rotation, you'll get your electrical energy for free - maybe we could use gigawatt lasers to carve it up.

Most asteroids probably don't rotate fast enough to have an outward centrifugal force at its equator. Asteroids are like giant mountains in space, I'm not sure that they wouldn't just fall apart and break up into chunks if rotated too fast. I think a solid metal asteroid with no faults and fissures could rotate quite fast. I've even heard proposals that you could make a space colony out of that, you simply focus the sun's rays on one of the poles and you melt a cavity in the center of the asteroid, and later on you add atmosphere, water and dirt, and you have a rotating asteroid colony. But I kind of doubt that most asteroids are one solid chunk of metal, I think they are in part at least held together by their own feeble gravity, the large ones anyway.

Grypd · 2006-09-17 15:41:54

Most asteroids probably don't rotate fast enough to have an outward centrifugal force at its equator. Asteroids are like giant mountains in space, I'm not sure that they wouldn't just fall apart and break up into chunks if rotated too fast. I think a solid metal asteroid with no faults and fissures could rotate quite fast. I've even heard proposals that you could make a space colony out of that, you simply focus the sun's rays on one of the poles and you melt a cavity in the center of the asteroid, and later on you add atmosphere, water and dirt, and you have a rotating asteroid colony. But I kind of doubt that most asteroids are one solid chunk of metal, I think they are in part at least held together by their own feeble gravity, the large ones anyway.[/quote]

Most asteroids will be found to be stony/Irons or C type. This means they will be easy to work on. Pure metal solid asteroids apart from there immense potential wealth are rare.

Still rotation of asteroids can be solved. If we use the engineering principle of Yo-Yo's then spin can be stopped by mass changes and long strings.

dicktice · 2006-09-17 21:32:30

Imagine a solar-powered laser cutting torch in the vacuum of space. (I'm reminded of the qarish paintings on some covers of Wonder Stories and other pulps of the 1930's, in which passenger spaceships are depicted horribly being cut into sections by beam weapons, with the beams brightly coloured of course. How about situating our prospecting ship some distance from a rotating asteroid, and slicing it into manageable hunks as it rotates, just like a baloney sausage?

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