could we build (or rebuild) a planet with asteroids?

[R1]

Moving a single asteroid probably wouldn't be difficult,<br /><br />Couldn't we have a few asteroids unite, and then allow the process to attract further small asteroids<br />by gravity, and practically clean up the asteroid belt, and basically building our own<br />man-made planet? <br /><br />If we pushed the first one, or pair of, or even small group of a few, fast enough, could we also control<br />the ultimate orbital speed of the planetoid, or synthetic planet, perhaps even to match earth's orbit,<br />so that it's always closest to earth? I think we should.<br /><br />We could conceivably control it's ultimate rotation speed also, to allow it to end up as close to 24 hours<br />per day, or have it always facing us, couldn't we?<br /><br />Think of all the benefits to science that could be obtained from that, and all from just moving a few<br />asteroids initially!<br /><br />Here's a different version, why shouldn't we build smaller versions that initially get programmed to end up <br />ultimately in Mars? <br /><br />Or even the one larger planetoid, if we could somehow initially program it's orbit while<br />it's easy to move one or two, to end up in Mars, could we improve Mars so it will have a little bit more gravity,<br />so it can retain water vapors and other gases that earth can, but Mars can not?<br /><br /> <div class="Discussion_UserSignature"> </div>

 

[h2ouniverse]

Asteroid belt total mass is very small.<br /><br />Ceres alone accounts for 30% of the total mass.<br />Accreting all asteroid belt mass onto Ceres would make it just 3 times heavier / bulkier hence a diameter of just 1400km. (and oa mass of 1/2000 th Earth's mass)<br /><br />Even the entire Kuiper belt is assessed just one tenth of Earth's mass.<br /><br />Then your dwarf planet or planet would be red hot for hundreds of millions of years, to dissipate the accretion heat (all the kinetic energies canceled)<br /><br />Btw it would be a pity to lose all the cumulated free surface, for the doubtful asset of creating a slightly larger gravity field...<br />Ceres surface is about the one of India. <br />It's far better to have hundreds of Ceres to colonize rather than a single sphere.<br />I do not see the interest.<br /><br />Regards.<br />

 

[R1]

It wouldn't be much total mass, true, <br /><br />It's less than our moon in total, but aren't they going to get lost eventually from the Jupiter effect ?<br /><br /><br />I would rather have a controlled artificial planetoid nearby.<br /><br /><br /><br /> <div class="Discussion_UserSignature"> </div>

 

[vogon13]

Transporting asteroids across Jupiter's orbital resonances across the belt will take energy, gravity from an accreting mass won't do it. You will have to move ALL of the asteroids.<br /><br />That's a big project.<br /><br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[dragon04]

"Fusing" the asteroids together to provide a stable body would be a real trick indeed.<br /><br />I don't think super glue or cement will work. <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[mithridates]

Ha, I always daydream about this subject too. The asteroid belt's lack of mass (as the others have said) wouldn't make it a realistic proposal, but one similar subject I've always wondered about is whether a massive enough moon around Ceres would aid in keeping an atmosphere. As far as I know Ceres is capable of sustaining an atmosphere for a few hundred years. Since atmosphere is lost when the solar wind hits an object and causes the particles to escape its gravity, what if there were a sufficiently massive object close enough that a certain percentage of particles that would have been lost would remain within the binary system?<br /><br />It would be helpful if anybody knows of any studies done on the Earth and the Moon or other planets and their moons regarding that. <br /><br />Back to the original subject, I know anything on this scale is simply massive but I could see a possible use far (very very very far) in the future for combining asteroids of very small masses in order to create a larger object that has just enough gravity to make it easier to function. With almost no gravity you have possible troubles with kicking up dust and having the dust being attracted to you by static electricity as you try to get things done, and you have to pretty much strap yourself in to keep from flying out into space. I could see combining two if it would result in a single body that didn't have these problems. <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[mithridates]

Oh, and also since gravity is created by mass and not size, it would certainly be much easier (well, one tiny step farther away from sheer impossibility) to inject material from more massive asteroids into others. Fill up a crater on Ceres with material brought in from a denser asteroid, that sort of thing. <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[h2ouniverse]

Hi,<br />I still think that would be a terrible waste of colonizable material. <br />For instance, Pluto and Eris have each areas equivalent to Russia (or US+Canada). Total Pluto+Eris = 35 millions of km2.<br />Merge them into a single dwarf and you get a 2970km-wide object with just 27 millions of km2. = /> You lose 25% of colonizable surface and close-to-surface volume.<br /><br />Continue with other Kuiper Belt bodies and the destruction of accessible surface amplifies so that you finally lose almost all of the initial one. You end up with a (red hot) object that has become a (very impractical!!!) gravity well. (*)<br /><br />A very very bad strategy imho.<br />Regards.<br /><br />(*) as a reminder, being currently at the bottom of a deep gravity well is what prevents mankind from colonizing space. We need to spend a tremendous amount of energy for each travel. Why reproduce the situtation elsewhere?<br />Also, most of Earth's mass is absolutely unusable for us, being too hot and too deep (the magma and the core).

 

[ashish27]

Right, instead of gathering asteroids together we should convert one single medium sized asteroid into a spaceship as shown many science fiction series most notably Gene Rodenberry's Andromeda. The Neiztchien fighter Tyr Anansazi lived in one such asteroid.<br />To convert an asteroid into a spaceship we need to first dig out rooms in it and then fit propulsion engines on the exterior.<br />Seems funny but I wouldn't be surprised if this indeed becomes man's way of venturing into deep space in the far future.

 

[h2ouniverse]

in reply to<br /><br />-----------<br />aren't they going to get lost eventually from the Jupiter effect <br />---------------<br /><br />at a short term (say 1 billion years, before M31 arrives), no.<br />The issue to me is the accessibility to matter. and for that, it is far better to keep it in the form of asteroids...<br /><br />Regards<br />

 

[tdamskov]

Simply hollow out the asteroid, fill with air and spin up for artificial gravity. Not only do you keep your atmosphere and a suitable gravity, you also gain protection from radiation as well. If you need to move it closer to the sun for heat/energy, the mined out mass can be used with a mass driver.

 

[vogon13]

Not sure how an asteroidal satellite would help Ceres hold an atmosphere.<br /><br />Additionally, Ganymede and Callisto are much more massive and colder and do not retain appreciable atmosphere, so I don't expect Ceres to have any chance at all.<br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[R1]

alright, well these are all good points, maybe Ceres, or any of the few of the largest ones, could very well be better than<br />trying to gather all, or even most of them, or any of them, for that matter.<br /><br />I like that idea of 'converting' one into a spaceship, too.<br /><br />Would it be a reasonably easy, (and a good idea,) to move one on two of the large ones to an orbit closer to earth?<br />With the asteroid belt fragmented it just doesn't seem like its a safe environment to do a lot of construction and mining<br />work in. I realize the asteroids are really sparse, but yet it seems more dangerous when I consider a lot of traffic in there,<br />as well as human crews that would be working in there for many days or weeks at a time. I imagine there's also<br />a lot of dust and gravel or brick sized objects that may have not yet been mapped, that could potentially cause<br />problems or injuries. <div class="Discussion_UserSignature"> </div>

 

[yevaud]

This is the best method, agreed.<br /><br />Our best trick is to do exactly this with multiple large Asteroids, making each a small colony. It's efficient, moves humanity outwards in hundreds of small increments, and provides a great deal of raw material and valuable elements. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[mithridates]

Well, Ganymede and the others are the result of billions of years of being left to their own designs, whereas pretty much any fairly well-sized body in the Solar System can be made to have an atmosphere for a few hundred years, I believe. That's a moment on the Solar System's time scale but for humans it could be long enough (since it can be replenished). <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[mithridates]

If you were moving one closer to Earth you would also want to make sure that the orbit was a good one though, because with an orbit too similar to ours you'd have a really long period of time in between launch windows. That's why Ceres is an easier target than Mars in terms of frequency, even though it takes about an extra month or two to get there (Dawn's taking a long time of course because it's taking a very long route with an ion engine). <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[R1]

right, ok, so it could be an orbit closer than Mars, and it could be stationary relative to earth, just<br />not closest to earth, but instead at the point where a trip to and from earth is the shortest possible.<br /><br />I'm a bit confused about an atmosphere:<br /> Even with all the asteroids put together, the total mass would be less<br />than our moon. Vogon seems to be right in that neither asteroid would therefore have enough mass to <br />hold an atmosphere, since our own moon is losing gases constantly to the solar wind.<br />I'm confused because Holmes would have not been able to remain spherical, is it<br />that the giant sphere is all particles and no gas ? <br /><br />How could a small asteroid, for example Ida's moon Dactyl, be best moved closer to earth?<br />At about 1.4 km in diameter, it seems to be large enough (maybe too large?) to make<br />some kind of a midway station to Mars and anywhere we go out of it.<br /><br />Would it take impossible amounts of fuel to move something this big as described?<br /><br /><br />wiki link to Dactyl:<br />http://en.wikipedia.org/wiki/Dactyl_%28moon%29<br /><br /><br /><br /><br /> <div class="Discussion_UserSignature"> </div>

 

[MeteorWayne]

An orbit in the Asteroid belt cannot be stationary with respect to earth.<br />The length of an orbit is directly related to it's orbital distance. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[R1]

oh, no I meant for the asteroid that that we bring closer to earth, in the recent revision. I'm afraid the<br />same might apply, however. Although If it's going to store fuel in addition to food and supplies, it<br />may be a simple matter to use small amounts of fuel to maintain a good position. This may not be as<br />critical of a need, though. For example, when a ship is sent from earth, the asteroid could then simply be advanced<br />at that time to rendevouz with the shipment from earth. I think the biggest problem would be bringing it<br /> to an orbit between Earth and Mars. Would the amount of fuel needed be unreasonable?<br />I'm thinking of a small asteroid, like the Dactyl moon or one even smaller, perhaps under 700 meters in diameter.<br /><br /><br /> <div class="Discussion_UserSignature"> </div>

 

[vandivx]

I do hope that all of you on this thread who contemplate such engineering are staunch defenders of capitalism and not proponents of today's green philosophy etc<br /><br />it always amazes me the split pple have when on one hand they see man virtually as a pest on the surface of Earth who is spoiling it by interfering with its 'natural development' by his activities and on the other hand they may contemplate such fundamental and far reaching projects as on this thread<br /><br />also anybody who worries about overcrowding in near future, let them settle northern Canada or Sweden/Norway or Siberia etc, after that is all densely populated including both north poles areas lets talk about settling away from Earth<br /><br />actually we should first also settle our seas and oceans because that would be infinitely easier any way you look at it than any moon/planet settling, hell we should first settle underground too, lots of space in man made caverns holding new cities...<br /><br />vanDivX <div class="Discussion_UserSignature"> </div>

 

[R1]

Well vanDivx, population and green philosophy have nothing to do with this post whatsoever,<br />I am so glad to say <img src="/images/icons/smile.gif" />, so that's taken care of. Or such is my hope.<br /><br />My perspective is from the expansion of science in the manned exploration of space,<br />which is in fact just around the corner, and its development is in fact ongoing as I type this.<br /><br />About capitalism, I don't know much to discuss here, but what alternative is there, <br />communism? fascism? imperialism? socialism? about the only thing to do with capital expenditure<br />that I can think of is that I'm pleased to see a requested budget allotment of <font color="yellow"> 9 Billion </font>ollars<br />for exploration alone within 4 1/2 years (about 50% of the total budget request for Nasa <img src="/images/icons/smile.gif" />! for 2012 alone).<br /><br />see link (under 2012 budget request allotments):<br />www.nasa.gov/pdf/168652main_NASA_FY08_Budget_Request.pdf<br /><br />as for exploring caves and oceans, actually earth science, relax, approx. 1.4 billion dollars is the allotment request<br />for each year from '07 thru '12 <br /> <div class="Discussion_UserSignature"> </div>

 

[nexium]

We can put tiny habitats at the mass center of a million asteroids. The air pressure would cause the asteroid to expand to destruction with air pressure inside a void bigger than a few cubic meters if the asteroid radius is less than one kilometer. Possibly we could band the asteroid like a large box to keep it from expanding. Small asteroids don't have enough gravity.<br />Also we can expect any size asteroid hollowed out and spun fast enough to produce significant gravity to disintigrate. Possiblly we can connect two hollow asteroids with a tether and spin them around each other to produce significant gravity, but we will need lots of banding.<br /><br />If we can make asteroid material into something a million times stronger than steel, we can build a hollow Earth size (thin wall) planet and inflate it with hydrogen from one of the gas giant planets; but it will have about the gravity of our moon due to low average density and low mass, so it will lose several percent of it's atmosphere on the outer surface per century. We could possibly locate it orbiting Earth with a circular orbit and a radius of about one million kilometers. From Earth, it would appear to be slightly larger than our moon. It could have several concentric spheres only a few meters different in radius, with the outer spheres transparent to let in sunlight, then we only loose atmosphere when a meteor breaks the outer spheres.<br />Somewhere around twice the radius of Earth, the surface gravity will be about one g, but we will need about twenty times as much hydrogen, and one million times stronger than steel may be marginal, if hit by a one kilometer asteroid. The above paragraph is far future.<br /><br />Near term, it is thought that there are hundreds asteroids, over one kilometer, which have approximately the same orbit as Earth, so we only have to travel a few million kilometers to reach habitats for the first 10,000 off planet humans. Neil

 

[tdamskov]

You miss the point of green conservation on Earth, then. <br /><br />It's not about having "room" for people, it's about preserving the biosphere of Earth while supporting a specific amount of people. Many of the sparsely populated areas of Earth are also sparse in energy and biological life - it makes no sense to populate them and then having to support them with food, energy and materials from elsewhere. Currently, humanity is nowhere near living sustainable in any sense of the word; our numbers, energy needs, and lust for modern lifestyles are rising, to the point where Earth simply cannot sustain the requirements for resources without massive impact on the biosphere.<br /><br />Adding artificial biospheres in space would allow humanity to lessen the strain on Earths habitats while also providing some security against species threatening disasters. But of course it's taking the very long view: as a solution it won't be be relevant in this century (or maybe even the next).

 

[tdamskov]

A combination of hollowing out and strengthening would probably be the most feasible. Most large internal spaces would have to be lined and supported with strong materials doing double duty as pressure containment (relieving external pressure on the rock) and thermal regulation. Water is an excellent heat store, but it's not clear if heat loss or heat buildup would be the major issue.<br /><br />Large parts of a human habitat in an asteroid need only be tunnels and rooms, not large cavities. Tunnels are far easier to protect against breaches and don't put as much stress on the structural integrity of the rock.<br /><br />Still, it's hard to visualize the requirements of building a human habitat with a possible lifetime of millions of years.<br />

 

[nexium]

If we consume energy at the first world average, inside the asteroid, disposal of waste heat will be the problem for even a moderate human density = 27 cubic meters per person. All waste heat needs to be radiated into space by the outer surface of the asteroid plus what ever heat is absorbed from the Sun.<br />Initially, it will take a year or so to heat the inside of the asteroid from 100 degrees k to 300 degrees k, if we can avoid heating it during the excavation. More likely, average rock temperatue will exceed 300 k before the excavating is complete.<br />There are tradeoffs between large cavity and tunnels, if we only have micro gravity. People would need to carry GPS (or mapquest) to avoid getting lost in a maze of tunnels. Air purifing, waste disposal, comfortable temperature, communications, light level and procurement of miscellaneous are all easier in a large free fall cavity. The same number of cubic meters as tunnels have lots more surface area to inspect for cracks than a spherical cavity. All cracks are dangerous in the outer wall: Analysis of innerwall crack hazard is very complex. If we have 4 psi of atmosphere inside (mostly oxygen) this produces a very large stress while negligible gravity produces very little stress; just the opposite of tunnels below Earth's surface. Neil