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Asteroid as the basis of a Space Station

Posted by: SteveXE - Tue Dec 06, 2011 5:58 am
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Asteroid as the basis of a Space Station 
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Post Re: Asteroid as the basis of a Space Station   Posted on: Thu Mar 01, 2012 2:33 pm
Lourens wrote:
Toutatis is only a few kilometres a side, on the same order of magnitude as the largest trawling nets used for fishing. If it's a rubble pile, why not wrap a big net around it to keep the bits together?
A few problems with this. 1st, if the dust is anything like lunar regolith, it's ultrafine, powder. (We don't know, we'd have to go there, and find out.) It'd also complicate mining the rock, which we're there to do in the first place. Any mass we take would have to make our job easier, or it's just not worth it.
JamesG wrote:
And it still masses megatons, if that got moving, it would easily overwhelm the tensile strength of the material. Same goes for sintering the surface together.

Still, one of the projected hazards of dealing with these kind of asteroids is that disturbing them could kick up a dust cloud that takes forever to settle. It will become a haze of dust pollution getting in the way and into machinery. Putting it in a "sock" might be a way of mitigating that.
I'm not sure how a dust cloud is that big a deal. I'm talking about automated mining, which could use other sensors besides visual spectrum sights, so radar would penetrate the haze just fine. The crew are there mostly to make decisions, repair, and probably for a sense of adventure, most of the work is done by robots. The dust may interfere with the workings, but according to the Appollo missions, it does. Whether it's hangign in a cloud, or picked up in your treads, it's a factor you have to account for. That's why you send a mechanic.

Even massing megatons, we think it's one mass (It could be two, closely bound by gravity, which might explain it's complex rotation.) If that's the case, ther wouldn't be any relative motion to stretch the net, it's all going the same direction at the same speed. The trick is going to be keeping it that way, except the mass we're removing for mining purposes. As I pointed out, any mass leaving is going to have a small, but measurable effect on it's motion, so when it comes time to land, or lift off, we'll have to be careful not to change the orbit for a colision course, or out of the harmonic which makes this such a tempting target. That could mean the crews might not have the fuel to return with their cargo.

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Post Re: Asteroid as the basis of a Space Station   Posted on: Thu Mar 01, 2012 5:15 pm
Ok, so I'm refining the backgound for my Interplanetary Nomad story, assuming Toutatis is, in fact a rubble-pile with a few large solid cores in the 2 main masses. The mining ship I'm designing is cylindrical, with one side made up of conveyors that move inward, carrying regolith to a central furnace. This clears under the Base, so it slowly sinks in to bury it'self, until it reaches bedrock.

The furnace is a Plasma Gasifier, which superheats the regolith to vaporize the volatile elements, and melt the metals into a liquid slag. This can be further refined for building materials, and I'm thinking about using it to line the tunnel. Eventually, the idea is to clear off at least one of the cores, and seperate it as a stand alone base. Through later missions, the other can be cleared, making 2.

One is to be left in the original orbit, for hitchiking out to the main belt, and returning with more asteroids. The other, I'm planning to de-orbit, and re orbit to Venus. This planet happens to have an 8:13 harmonic with our's, so a Nomad base could ferry between them every 5 years. (This is fairly close to the Phi ratio, AKA "Golden Mean", or Fibonacci Fraction, so the cloud cukoo landers like to use it to draw Pentagrams around the sun.)

I'm intersted in Venus because 1) it's the closest to Earth, and 2) it's got more Atmosphere than it needs. If we're going to do any Terraforming, we're going to need enough gasses to cover the planet in question, such as Mars. And finally, it's relatively close to the Solar Power Supply, so there should be plenty of energy to run an Interplanetary Industrial Economy. While we could get our gasses from Earth, just as easier (our gravity well is slightly deeper, but we're right here, so we don't need to go and get it, and we have a moon.) but that's a bad idea, because we're using it.

Venus is uninhabited, as far as we know, and has hunderds of times as much oxygen (or actually, Carbon Dioxide), so we'll probably never significantly deplete it by gas mining. (if we could, then it could be one of the first steps to terraforming it.) At this point, the Earth/moon system would be a transfer point, between Gasses from Venus every 5 years, and materials from the main belt every 4. That would be more than enough to build on the planetary scale, or habitats to evacuate the entire human race, possibly even make generation ships for interstellar travel.

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Post Re: Asteroid as the basis of a Space Station   Posted on: Thu Mar 01, 2012 5:26 pm
Psiberzerker wrote:
I'm not sure how a dust cloud is that big a deal. I'm talking about automated mining, which could use other sensors besides visual spectrum sights, so radar would penetrate the haze just fine.


That depends on its composition and how thick it is. If it has a high metallic content, radar will be screwed. The haze may wind up becoming like a cometary tail and coat sensors, solar panels, ect. of vehicles and equipment. If it coats or changes the albedo of heat radiator surfaces, you could have overheating problems.


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Even massing megatons, we think it's one mass


You think/hope its one mass. There is no proof of that one way or another. All asteroids above a certain size may be "rubble piles". Non-solid objects but without the gravity or fluidity to take on a spherical shape. These asteroids may be so delicate that just landing something on it may causes the whole object to start shifting around. Think of them as more like millions of small asteroids in close formation lightly bound by their gravity than a single object.

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If that's the case, ther wouldn't be any relative motion to stretch the net, it's all going the same direction at the same speed. The trick is going to be keeping it that way, except the mass we're removing for mining purposes.


Every molecule that isn't attached to its neighbor has its own inertial momentum. Any change in vector is going to induce stress and motion in every element of the object.

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As I pointed out, any mass leaving is going to have a small, but measurable effect on it's motion, so when it comes time to land, or lift off, we'll have to be careful not to change the orbit


Mass moving around will change its center of gravity and thus rotation, but won't affect the orbit much. Controlled landings and take offs of rockets won't induce any meaningful DV to the object. You would need something like a mass driver (rail gun) to do that.


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Post Re: Asteroid as the basis of a Space Station   Posted on: Thu Mar 01, 2012 5:59 pm
Psiberzerker wrote:
Ok, so I'm refining the backgound for my Interplanetary Nomad story, assuming Toutatis is, in fact a rubble-pile with a few large solid cores in the 2 main masses.


Ok, I'll buy that one.


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Eventually, the idea is to clear off at least one of the cores, and seperate it as a stand alone base. Through later missions, the other can be cleared, making 2.


By that time, it would probably look more like a ship/or station than an asteroid.

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One is to be left in the original orbit, for hitchiking out to the main belt, and returning with more asteroids. The other, I'm planning to de-orbit, and re orbit to Venus.


You mean orbit Venus or put it in a solar co-orbit with Venus?


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I'm intersted in Venus because 1) it's the closest to Earth, and 2) it's got more Atmosphere than it needs. If we're going to do any Terraforming, we're going to need enough gasses to cover the planet in question, such as Mars.


That's not likely. Mars would lose whatever gases you could deposit faster than you could get them there with anything short of crashing a comet into it. And even then it would still bleed off over a few centuries.

Actually Venus is a better candidate for your story. Say you successfully park your Chunk o' Toutatis near Venus. You use its material to build "sun shades" at Venus' L1 point of enough surface area to occult the solar radiation of the sun. This allows the planet to cool (eventually) and even have the CO2 freeze out of the atmosphere and reduce the pressures. It will never be Earth-like, but some of the polar highland regions might actually get near Earth range pressures and temperatures.


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Post Re: Asteroid as the basis of a Space Station   Posted on: Thu Mar 01, 2012 6:47 pm
JamesG wrote:
You mean orbit Venus or put it in a solar co-orbit with Venus?
A harmonic coorbit between Earth, and Venus with a period of about 5 years for ferrying goods/personell back, and forth.
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That's not likely. Mars would lose whatever gases you could deposit faster than you could get them there with anything short of crashing a comet into it. And even then it would still bleed off over a few centuries.
I agree, people seem to be obsessed with Mars as the first extraterran colony, but it's surface gravity is too low to Ever hold a permanent atmosphere like we're used to. And, as you say, it would take centuries, probably dissapating in the process without a massive addition all at once.
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Actually Venus is a better candidate for your story. Say you successfully park your Chunk o' Toutatis near Venus. You use its material to build "sun shades" at Venus' L1 point of enough surface area to occult the solar radiation of the sun. This allows the planet to cool (eventually) and even have the CO2 freeze out of the atmosphere and reduce the pressures. It will never be Earth-like, but some of the polar highland regions might actually get near Earth range pressures and temperatures.
Without a doubt, but the sun-shade idea would only cool it, not deal with the cause of the problem, CO2, nor the sulfuric acid-rain which would also make it less than ideal to live on. This is a bit beyond the central theme of an Asteroid base, but my proposal uses genetically engineered balloon like plants to strip off oxygen by photosynthesis at high altitude, above the brimstone clouds. Since the energy is coming from sunlight, it's not adding to the greenhouse effect, and there's some shading too. The great thing is, we don't have to build the whole thing, simply make them capable of reproducing, and spreading across the skies on their own. Therefore, we'd be using a cumulative effect to counter a cumulative effect. And lastly, this frees up a lot of oxygen to be shipped around to our other interplanetary projects, such as space habitats, main belt asteroid mining (the crews will ned to breathe something.), and potentially terraforming.

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Post Re: Asteroid as the basis of a Space Station   Posted on: Thu Mar 01, 2012 11:20 pm
Where are these floating balloon plants going to get all of the other nutrients they need to live, much less self replicate? Gotta have more than just CO2.

Cooling the planet will allow the sulfuric acid and etc. to condense and fall out of the atmosphere where it will catalysis locking up some of the carbon into rocks and generate water. Basically starting the same process that occurred on Earth (maybe, depending on what the geochemistry is on the surface after all these billions of years of being cooked). If nothing else, you could completely "turn off the sun" and let the entire atmosphere freeze and the CO2 precipitate out into ice sheets, then gradually allow it to thaw or process it somehow. Hit the "reset button" on the planet.


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Post Re: Asteroid as the basis of a Space Station   Posted on: Fri Mar 02, 2012 12:45 am
JamesG wrote:
Where are these floating balloon plants going to get all of the other nutrients they need to live, much less self replicate? Gotta have more than just CO2.

Cooling the planet will allow the sulfuric acid and etc. to condense and fall out of the atmosphere where it will catalysis locking up some of the carbon into rocks and generate water. Basically starting the same process that occurred on Earth (maybe, depending on what the geochemistry is on the surface after all these billions of years of being cooked). If nothing else, you could completely "turn off the sun" and let the entire atmosphere freeze and the CO2 precipitate out into ice sheets, then gradually allow it to thaw or process it somehow. Hit the "reset button" on the planet.


Sulphur is one of those Nutrients, to make peptides into proteins, but as the main effect we're looking for here is carbondyoxide remediation, and I'm talking about Genetic Engineering, we could conceivably make an extremely simple organism, or symbiotic colony, of green algae in a fungoid substrate. Photosynthesis makes sugar (C6H12O6) out of 6 each of CO2, and Water. The only other nutrients that would be needed in trace quantities would be Sulpher, and Nitrogen, both of which are present. About the only thing that's relatively rare there is Hydrogen, mostly in Flourides, and Chlorides. That could be suplimented by orbital factories from the solar wind.

You can't freeze Venus to below the freezing point of CO2, (-80 centigrade, at sea level, on Earth), because it's too close to the sun. Even if we could, the idea is to make it liveable, and dry ice glaciers aren't a great place for humans. We also need free oxygen to breathe, which is in short supply there, unless you reverse the greenhouse effect by liberating it.

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Post Re: Asteroid as the basis of a Space Station   Posted on: Fri Mar 02, 2012 1:06 am
Psiberzerker wrote:
Sulphur is one of those Nutrients, to make peptides into proteins, but as the main effect we're looking for here is carbondyoxide remediation, and I'm talking about Genetic Engineering, we could conceivably make an extremely simple organism, or symbiotic colony, of green algae in a fungoid substrate. Photosynthesis makes sugar (C6H12O6) out of 6 each of CO2, and Water. The only other nutrients that would be needed in trace quantities would be Sulpher, and Nitrogen, both of which are present. About the only thing that's relatively rare there is Hydrogen, mostly in Flourides, and Chlorides. That could be suplimented by orbital factories from the solar wind.

That's quite a handwavium leap. Sugar synthesis doesn't just happen, it takes all kinds of enzimes, other chemical machinery, and lots of water. What you are describing is closer to nanomachines than biology.


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You can't freeze Venus to below the freezing point of CO2, (-80 centigrade, at sea level, on Earth), because it's too close to the sun.


You can if you block out the sun.


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Post Re: Asteroid as the basis of a Space Station   Posted on: Fri Mar 02, 2012 3:07 am
JamesG wrote:
That's quite a handwavium leap. Sugar synthesis doesn't just happen, it takes all kinds of enzimes, other chemical machinery, and lots of water. What you are describing is closer to nanomachines than biology.
Ok fine, it's science fiction, did I mention that? All those enzymes are made out of primarilly carbon, oxygen, and hydrogen(Carbo-hydrates) polymerized together with nitrogen, and sulpher.

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You can if you block out the sun.
With a solar shade large enough to cover a planet the size of the Earth half the distance from the sun, at the libration point, millions of miles away, that's a lot more "handwavium". What're you going to make it out of, how is it going to get there, and how do you prevent all that surface area from 1 vaporizing, and 2 sailing into the planet?

Assuming you pull off all those miracles, remember, we're trying to make the planet Livable? Who wants to live on a glacier of dry ice? Make that a lot of handwavium for nothing.

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Post Re: Asteroid as the basis of a Space Station   Posted on: Fri Mar 02, 2012 3:45 am
Psiberzerker wrote:
Ok fine, it's science fiction, did I mention that? All those enzymes are made out of primarilly carbon, oxygen, and hydrogen(Carbo-hydrates) polymerized together with nitrogen, and sulpher.


Go wiki up the biochemistry of photosynthesis.

You said you wanted hard sci-fi. I'm making it hard for you. :P

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With a solar shade large enough to cover a planet the size of the Earth half the distance from the sun, at the libration point, millions of miles away, that's a lot more "handwavium". What're you going to make it out of, how is it going to get there, and how do you prevent all that surface area from 1 vaporizing, and 2 sailing into the planet?


Its just a piece of mega-engineering. We could probably do it today if we put our minds and resources to it. You could take your several cubic KMs asteroid and pound it into a few hundred, several thousand KM^2 diameter shades only a few millimeters thick and use the interrupted solar energy to maintain its station keeping. You don't have to block all of the light reaching the planet, as little as 50% will probably do the trick.

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Assuming you pull off all those miracles, remember, we're trying to make the planet Livable? Who wants to live on a glacier of dry ice? Make that a lot of handwavium for nothing.


The idea is to break the planet's run-away green house effect. Chilling it is only the first step and a way of getting the atmosphere under control and in a form that can be converted into something more pleasant. Much like a large percentage of the Earth's surface is what we would call inhospitable because its at the bottom of crushing water pressure, so to would be Venus, but there may be places that are "just right".


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Post Re: Asteroid as the basis of a Space Station   Posted on: Fri Mar 02, 2012 5:34 am
JamesG wrote:
Go wiki up the biochemistry of photosynthesis.
I did. I may still be a bit of a nijbe here, but I think I've seen enough to know what you expect of your fellow posters. I'm not them, I do, in fact research all the related subjects, and make an effort not to post unless I have a good idea of WTF I'm talking about. That's Natural Photosynthesis, and I feel fairly confident that it can be simplified, a lot.

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Its just a piece of mega-engineering. We could probably do it today if we put our minds and resources to it. You could take your several cubic KMs asteroid and pound it into a few hundred, several thousand KM^2 diameter shades only a few millimeters thick and use the interrupted solar energy to maintain its station keeping. You don't have to block all of the light reaching the planet, as little as 50% will probably do the trick.
1st off, you said cool it to the point that the CO2 precipitates out. Survey says? EHHHHHNT! Now, you can backpedal a bit to lowering it to survivable temperatures, and that may be a bit more realistic, but that still doesn't change the fact that the surface pressure is comperable to under 27' of water on Earth, the air it'self is corrosive, and we still can't breathe it.

Quote:
The idea is to break the planet's run-away green house effect. Chilling it is only the first step and a way of getting the atmosphere under control and in a form that can be converted into something more pleasant. Much like a large percentage of the Earth's surface is what we would call inhospitable because its at the bottom of crushing water pressure, so to would be Venus, but there may be places that are "just right".


Or, we could at least try to deal with all of those first steps in 1 swell foop, and use pseudo biological processes to do it automatically so it doesn't require any gigaengineering (3 orders of magnitude more than Mega) beyond the ship to get it there. I don't think you understand the scale of the sheild you're proposing. To do it on Earth, we'd need one with the diameter of the moon, all right? Now, Venus is half the distance from the sun, so double that diameter, square the area, then move it out to the libration point, and you're talking about several times the diameter of the planet.

http://en.wikipedia.org/wiki/Terraforming_of_Venus

There's your wiki artical.

Now, assuming you made it, you'd have to keep it there. You can move it inward, to counteract the solar wind, but that's not constant, with storms, and it's close enough to be perturbed by the gravity of mercury zipping by a couple times a year. That means making it capable of thrusting, without collapsing to compensate. I'm not saying it can't be done, I just figure we'll have bottom up genetic engineering first.

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Post Re: Asteroid as the basis of a Space Station   Posted on: Fri Mar 02, 2012 6:13 am
Psiberzerker wrote:
That's Natural Photosynthesis, and I feel fairly confident that it can be simplified, a lot.


I'm sure the Nobel Committee is eagerly awaiting you with baited breath.


Quote:
1st off, you said cool it to the point that the CO2 precipitates out. Survey says? EHHHHHNT! Now, you can backpedal a bit to lowering it to survivable temperatures, and that may be a bit more realistic, but that still doesn't change the fact that the surface pressure is comperable to under 27' of water on Earth, the air it'self is corrosive, and we still can't breathe it.


You are getting obnoxious and immature again.

You'll never be able to breathe Venusian atmosphere, short of magical powers to install an Earth's atmosphere an hydrosphere there. And even then, the planet's lack of a magnetic field and sluggish orbital period would mean that without a shield, your nice atmosphere would quickly go back to being just as nasty as it was.

There are only a few of ways of reducing the mass and volume of a planetary atmosphere. Burn it off, freeze it down, or lock it up into rocks and organic goo. Earth used the later method. On contemporary hellish Venus, the most "practical" way is to freeze it and then rewarm, "reinflate" it the way you want to, perhaps by finding a way to unlock a lot of nitrogen out of the rocks along with converting the existing composition into oxygen and water, so that Terran-like lifeforms could possibly survive in some locations. But that, even in the best of cases, is a multi millennial process and project.

Quote:
Or, we could at least try to deal with all of those first steps in 1 swell foop, and use pseudo biological processes to do it automatically so it doesn't require any gigaengineering


What do you think terraforming is? Sorry, there is no easy solution.

The root problem Venus has is too much heat & solar energy. Any scheme has to address that first.


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Post Re: Asteroid as the basis of a Space Station   Posted on: Fri Mar 02, 2012 8:09 am
JamesG wrote:
You are getting obnoxious and immature again.
Sorry.

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You'll never be able to breathe Venusian atmosphere, short of magical powers to install an Earth's atmosphere an hydrosphere there. And even then, the planet's lack of a magnetic field and sluggish orbital period would mean that without a shield, your nice atmosphere would quickly go back to being just as nasty as it was.
Which brings us back to my original proposal, using the liberated Oxygen for other projects, like oxidizer for burning fuel, and atmosphere for large scale habitat building with the captured asteroids.

Quote:
There are only a few of ways of reducing the mass and volume of a planetary atmosphere. Burn it off, freeze it down, or lock it up into rocks and organic goo. Earth used the later method. On contemporary hellish Venus, the most "practical" way is to freeze it and then rewarm, "reinflate" it the way you want to, perhaps by finding a way to unlock a lot of nitrogen out of the rocks along with converting the existing composition into oxygen and water, so that Terran-like lifeforms could possibly survive in some locations. But that, even in the best of cases, is a multi millennial process and project.
Right, but cooling it down to cryogenic temperatures, then heating it back up would at least double that time. 2000 years is still much longer than one. Regardless, your solar shield idea wouldn't be stable on those timescales for the aforementioned reasons, and even if it would be possible, it would take yet more time. If we're talking about spending generations on such a project, then any time saving we can do would be worth it, and multiplying the problem would be counter-productive at the very least.

As far as the Nobel Prize Comittee is concerned, they'll have to wait, as I'm an engineer, not a biologist. I'm just trying to apply Occam's Razor here to see what steps can be excized, or at least pared down to make it remotely doable before the sun expands to a red giant, and make the plans moot. You think that's bad, you should see my original idea to move Mercury into orbit as a moon, and use it to speed up Venus' rotation.

I do appreciate your feedback, it helped me a lot. That's why I post these things in places like this, and expose them to criticism. It helps me think them through more thoroughly than I can by myself. Unfortunately, I feel we've strayed far enough from the OP on Asteroid exploitation for now.

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Post Re: Asteroid as the basis of a Space Station   Posted on: Fri Mar 02, 2012 8:28 am
JamesG wrote:
That depends on its composition and how thick it is. If it has a high metallic content, radar will be screwed. The haze may wind up becoming like a cometary tail and coat sensors, solar panels, ect. of vehicles and equipment. If it coats or changes the albedo of heat radiator surfaces, you could have overheating problems.
Good points.

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All asteroids above a certain size may be "rubble piles". Non-solid objects but without the gravity or fluidity to take on a spherical shape. These asteroids may be so delicate that just landing something on it may causes the whole object to start shifting around. Think of them as more like millions of small asteroids in close formation lightly bound by their gravity than a single object.
Right, but still a mass of rubble. I was refering to the posibility that it's two, or more non-contact masses that have a bit of the roiling semifluid mess you're refering too roughly between them, which probably means a couple solid cores under all that. (Or a "Contact Binary.") On the other end of the ruble pile spectrum, it could be a more coheisive single mass of countless peices held together enough by gravity to be counted as "1 mass" as far as velocity, and momentum are concerned. Not on the molecular level, there is some heat in there, but the smaller peices not moving in relation to each other. Now, this isn't solid by any stretch of the imagination, but that would make mining easier, if it could be done safely.

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Every molecule that isn't attached to its neighbor has its own inertial momentum. Any change in vector is going to induce stress and motion in every element of the object.
Right, but if those individual momenta are in the same direction, with the same speed, they're moving together. Just like the Ursa Major Cluster, a Mass of seperate, but gravitationally bound stars have a net momentum as they move.

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Mass moving around will change its center of gravity and thus rotation, but won't affect the orbit much. Controlled landings and take offs of rockets won't induce any meaningful DV to the object. You would need something like a mass driver (rail gun) to do that.
Which would probably break it up to the aforementioned shotgun pattern of potential impactors. That's what I was talking about, not changing the entire orbit of the mass to hit the Earth. The force of such a mass driver would be much more likely to break up a rubble pile than a careful planned landing, and anything you accellerated with the railgun would have a different trajectory, which could turn them into impactors. Probably ones that would burn up in our atmosphere, but a threat to anything we have in space, such as sattelites. bsides, the idea is I don't want to change the net orbit, it's convenient for hitching rides out to the main belt.

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Post Re: Asteroid as the basis of a Space Station   Posted on: Fri Mar 02, 2012 8:36 pm
I think venus would be better suited for gradual resource removal via robotics and automation. That bieng said I think that terraforming is not really as essential as a reliable ship with a self contained fuel factory. Just suit up go outside work etc and then go back to the ship to live. Terraforming assumes we should adapt planets...... it seems like adapting people would be less wor'k via genetics and nanotech.

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