[Moontanman]

Wow! Is it safe to stick my head out yet? I figured UncleAl would have tried to lop it off by now!

There is no doubt establishing the first of these colonies would be difficult and expensive but as the colonies in the "New World" were eventually able to not only support themselves they were able to be a powerful player in the affairs of the world.

Eventually building colonies will be similar to the building of cars. The first cars were built by hand one at a time, assembly line production put cars into the price range of nearly everyone. The same will be true for space colonies.

At first only governments and groups of governments will be able to build them but eventually smaller groups will be able to do so and then maybe even families will have their own "estates" in space.

Toroidal colonies can be stacked one on top of another to make mega cities of urban landscapes and even completely wild areas (at least in appearance).

Space colonies will be the start of bigger things maybe even the next step in the evolution of human culture, and the products of the colonies will become ever more important to the Earth and will enable the start of migration to the stars.

It might be hundreds or even thousands of years but the stars will be part of our future, if not we have no future.

[freeztar]

Originally Posted by Moontanman

It might be hundreds or even thousands of years but the stars will be part of our future, if not we have no future.

The closest star, Alpha Centauri, is 41.5x10^12 km (25.8 trillion miles) away. Traveling at 41.5 km/sec would put us there in 1 trillion seconds. That is equivalent to ~32,000 years!

Nonetheless, I think extraterrestrial habitation is a good idea/goal for humanity.

[Moontanman]

Originally Posted by freeztar

The closest star, Alpha Centauri, is 41.5x10^12 km (25.8 trillion miles) away. Traveling at 41.5 km/sec would put us there in 1 trillion seconds. That is equivalent to ~32,000 years!

Nonetheless, I think extraterrestrial habitation is a good idea/goal for humanity.

Magnetic sails could be used to propel these colonies to the stars, .1% of the speed of light should get you there in 4,000 years 1% in 400 years. Even if there are no planets there would be orbiting debris and that is all you need to colonize that solar system and then move to another. No need for faster than light or even relativistic travel just slowly going from one star to another. Say the number of stars double every thousand years, in a hundred thousand years it would be a lot of stars!

[Boerseun]

Up to this point, I've only heard the pros of spacecolonies in the asteroid belt.

There's a downside, however.

The popular notion is to hollow out these big chunks 'o rock, spin them up, and live on the inside in a comfy, almost earthlike, centrifugally-induced gravity.

There's a tiny problem with this, however:

You're proposing to remove round about 80% of the asteroid's mass through mining.

ALL the removed material must be removed somehow, otherwise you won't be able to spin the sucker up. You can't have a "resource" cloud hanging next to your spinning asteroid. It'll simply fly away.

Now, if you remove 80% of an asteroid's mass, you change its orbit. See it as a big rock-rocket. The expulsion of mass through your digging venture acts exactly like a big, fat, lazy rocket.

But consider this:

There are billions upon billions of asteroids between Mars and Jupiter. You pick one, you modify it to make it livable, thousands of pioneers move in, and now you've gone and changed the orbit. You'll have thousands of hectic collisions in your future with big rocks that haven't been mined yet - heavier than you, meaning you'll come off second best. Also, starting up a dodge'm track in the asteroid belt cannot be healthy for Earth in the long run, either.

If you wanna start up something in space, I proposed either Mars, or the Jovian moons. Any one of them is big enough not to have their orbits changed to a dangerous level by human activities.

Starting your enterprise in a gravity well like I propose above makes the shipping of resources hard, though. But that's the whole point, innit? You go where the resources are? Else we can just mine the resources with robots and be done with it. The whole reason for colonies is to exploit the resources for themselves - so what would it matter if it was in a gravity well?

But, in my own opinion, due to the nature of the asteroid belt, my advice would be to stay the hell away. They seem relatively stable now, the last big one to whack Earth was aroun 65 million years ago, doing the dinos in. We shouldn't tamper with them - any proposed "mining" activity will alter the orbit of whatever is being mined with unpredictable results. You might just find a nice nickle-bearing rock and destroy humankind in the process.

[Pyrotex]

Altering the orbit of an asteroid with "unpredictable" results would occur only if you refused to calculate the new orbital parameters with, say, a modest laptop computer. Ejecting the dug-out mass with a "mass-driver" would, in fact, effect even MORE changes in asteroid speed, and permit the residents to move the asteroid where it would endanger no one. There's plenty of space between Mars and the Belt, and between Earth and Mars, for thousands of stable asteroid orbits.

But still, no matter how you slice and dice, the big number 1 problem of space colonies will be: RADIATION.

There may be a solution on the horizon. I forgot where I read it (maybe here in Hypo), but scientists are experimenting with composite materials containing pockets of super-density. I can imagine huge sheets of graphene quilted together with nanotubes, so that the actual nuclear density exceeds that of Osmium-Iridium. A million such sheets, stacked together would be as thick as a piece of paper, and might ("might!") stop or reflect most radiation.

[Moontanman]

Originally Posted by Pyrotex

Altering the orbit of an asteroid with "unpredictable" results would occur only if you refused to calculate the new orbital parameters with, say, a modest laptop computer. Ejecting the dug-out mass with a "mass-driver" would, in fact, effect even MORE changes in asteroid speed, and permit the residents to move the asteroid where it would endanger no one. There's plenty of space between Mars and the Belt, and between Earth and Mars, for thousands of stable asteroid orbits.

But still, no matter how you slice and dice, the big number 1 problem of space colonies will be: RADIATION.

There may be a solution on the horizon. I forgot where I read it (maybe here in Hypo), but scientists are experimenting with composite materials containing pockets of super-density. I can imagine huge sheets of graphene quilted together with nano tubes, so that the actual nuclear density exceeds that of Osmium-Iridium. A million such sheets, stacked together would be as thick as a piece of paper, and might ("might!") stop or reflect most radiation.

I am not promoting hollowing out asteroids, I am promoting using the materials in space to construct toroidal rotating space colonies. Radiation will be a problem, special materials (rock foam is one), magnetic fields, charge fields, mass can negate this problem. If the colony is big enough the walls can be thick enough to block radiation. It is a problem but not an insurmountable one. Every one seems to have their own paradigm as to what a space colony is, T-bird thinks it's a tin can, others think of a hollow asteroid, some think of a think fragile metal tube. I think of a robust donut shaped object made of carbon nano tubes and rock and metal foam. Instead of mirrors I would like to see light collected by and transfered by fiber optics so we could eliminate the weak link of mirrors and transparent windows. Some of my ideas have not been identified with space colonies but to me using them is obvious. When you build something like this you have to look outside the box and use disparate technologies if they are the best at getting the job done. I started to post this in the engineering section instead of space. The technology is out there but it's up to us find it and bring it into the fold. Instead of just naming reasons why it can't be done lets hunt for solutions to the problems. Most are already available we just need to bring them together.

[Thunderbird]

Why would we need to do all this? I still do not understand how the cost is jusified by any benifits.

[Pyrotex]

Okay MooMan,
no hollowed out asteroids. It's space colonies. But can we have a conversation about shape / geometry?

The best use of materials that maximizes both internal volume and usable "floor-space" (that is, horizontal load-bearing area) is the cylinder, not the toroid.
Both can be spun on their axis to provide centripetal force. Both would use mirrors to reflect sunlight down their spin axis and then outward (from the axis) to illuminate the "floor-space" within.

The cylinder has another advantage, in that it can be built in modules, "disks" that can be attached at the back-side of the growing cylinder, much like soldering nickels together to make a cylinder.

Both cylinders and toroids can be attached together in pairs in order to cancel out the angular inertia. Angular inertia is inconvenient in space. Set up your colony to point at the Sun from a distance of 1 AU, and 6 months later, it points directly AWAY from the Sun. Major bummer. Building them in linked pairs lets you slowly turn the structure as it revolves about the Sun.

[Moontanman]

Originally Posted by Thunderbird

Why would we need to do all this? I still do not understand how the cost is jusified by any benifits.

No matter how green we are humans will eventually destroy the earth's ecosystems and humans will become extinct. The Earth is finite, the human race is not. the only way the human race and the Earth's ecosystem can survive is for humans to move into space. Any culture that is not advancing is declining, there is no way to maintain a static society. Colonies are a way to obtain natural resources with out destroying the Earth's ecosystems, materials that cannot be made o the earth can be made in space (metal foam is one of the potentially most useful things we could make in space, huge crystals, zero gee bearings, the list is quite long.) To make these things will require people living in space. It would be far too expensive to maintain small factories from the Earth. Finally how can you put a price on the insurance value of not having all your eggs in one basket should a planetary disaster occur? Humans got to where they are by advancing, expanding to the next level, the next level is space. No matter what we do the Earth will become uninhabitable sooner or later. I love the Earth, I want to do all I can to make it a better place but no matter how hard I or everyone else tries it will eventually die. We can either Terra form other planets which will eventually die just like the earth or we can start making small versions of the Earth in the form of space colonies. If we do we will never run out of resources or space and we will have the opportunity to occupy the entire galaxy and leave all the planets to evolve in their own way. Not only will we survive but the genome of the Earth will survive as well. We will take as many animals and plants with us as we can. the more complex we make our artificial ecosystems the better they will be for us. Does any of this make sense to you?

[Moontanman]

Originally Posted by Pyrotex

Okay MooMan,
no hollowed out asteroids. It's space colonies. But can we have a conversation about shape / geometry?

The best use of materials that maximizes both internal volume and usable "floor-space" (that is, horizontal load-bearing area) is the cylinder, not the toroid.
Both can be spun on their axis to provide centripetal force. Both would use mirrors to reflect sunlight down their spin axis and then outward (from the axis) to illuminate the "floor-space" within.

The cylinder has another advantage, in that it can be built in modules, "disks" that can be attached at the back-side of the growing cylinder, much like soldering nickels together to make a cylinder.

Both cylinders and toroids can be attached together in pairs in order to cancel out the angular inertia. Angular inertia is inconvenient in space. Set up your colony to point at the Sun from a distance of 1 AU, and 6 months later, it points directly AWAY from the Sun. Major bummer. Building them in linked pairs lets you slowly turn the structure as it revolves about the Sun.

I agree, toroids make better sense if they are stacked on each other like many bicycle wheels attached at the hub. many moderately sized ones make more sense than one huge toroid, each toroid could be a different ecosystem and or city. If one was holed catastrophically the others would be unharmed and be there to repair the damage and rescue the inhabitants.