Orbiting Toroidal Space Colonies

[Moontanman]

I have promoted space colonies several times in widely varying posts. Often they were dismissed as living in a can in the vacuum of space. Here is a more descriptive version.

 

http://www.belmont.k12.ca.us/ralston/programs/itech/SpaceSettlement/70sArt/AC75-1886f.jpeg

 

What is an Orbital Space Colony?

[UncleAl]

1) International Space Station Freedom FUBAR Space Hole One Alpha, giggle.

2) If ya had 'em, what would ya do with 'em to justify cost and upkeep?

3) Annual Quadrantid, Orionid, Taurid, Leonid, Perseid, etc. meteor showers.

4) Orbital Debris Graphics

5) Massive solar coronal eruptions - everybody gets cooked. Incidence of radiation cataracts in Mir and ISS FUBAR asstronaughts is ~100%.

6) Where do you put the orbit? In close (to 200 mile atlitude) the orbit decays from residual air resistance. Out further you are in the van Allen radiation belts. Out further still and ground to orbit is way expensive (and lethally slow in an emergency).

7) Internal security.

 

Before you set out on an expensive trip it helps to have a destination.

[Thunderbird]

Moontanman are you familiar with the bio-sphere 2 project ?

fiasco

http://http://biology.kenyon.edu/slonc/bio3/2000projects/carroll_d_walker_e/lessons.html

[Moontanman]

Moontanman are you familiar with the bio-sphere 2 project ?

fiasco

http://http://biology.kenyon.edu/slonc/bio3/2000projects/carroll_d_walker_e/lessons.html

 

Your link didn't work but if you are referring to the big greenhouse in the desert it was far too small and relied on natural processes to maintain the atmosphere. what my link should have taken you to is far bigger, they even say habitats tens of kilometers across are doable and they wouldn't simply try to maintain a natural biosphere to feed the inhabitants and provide an atmosphere.

[Moontanman]

1) International Space Station Freedom FUBAR Space Hole One Alpha, giggle.

 

You are of course correct, all these "space stations" were doomed from the start, far too small and flimsy. You can't build in space by bringing materials from the earth.

 

2) If ya had 'em, what would ya do with 'em to justify cost and upkeep?

 

They are colonies, the initial purpose would be to expand the human race but they could also be a base for asteroid mining, zero gee manufacturing, places to grow food stuffs to support all types of space initiatives, (IE space power stations) and simply places to get away from the Earth. Any way you look at it they would have to pay for themselves in some way.

 

3) Annual Quadrantid, Orionid, Taurid, Leonid, Perseid, etc. meteor showers.

 

Meteors could be a problem although most sources seem to think they can be overcome by special materials for small ones and defensive measures for larger ones. I am not trying to dismiss this out of hand but meteors should not be a big a problem for a small object as they are for an object as big as the earth. Even a very large meteor shower for the earth where you might see several a second would not be a problem for a small object with a cross section many orders of magnitude smaller.

 

4) Orbital Debris Graphics

 

Since no colony would be in Earth orbit this is not a problem.

 

5) Massive solar coronal eruptions - everybody gets cooked. Incidence of radiation cataracts in Mir and ISS FUBAR asstronaughts is ~100%.

 

A large colony would would have walls more than thick enough to protect it's inhabitants from particle radiation, Magnetic fields and charged fields could provide even more. The thick walls would be more than enough protection from EMR.

 

6) Where do you put the orbit? In close (to 200 mile atlitude) the orbit decays from residual air resistance. Out further you are in the van Allen radiation belts. Out further still and ground to orbit is way expensive (and lethally slow in an emergency).

 

First of all, as I said colonies would not be in Earth orbit a really big colony wouldn't benefit from being rescued from the earth to begin with. No space craft would be big enough to carry hundreds of thousands of people back to earth. So this is a moot point. where in orbit? Lagrange points of Earth orbit and the moons orbit. Jupiter's Lagrange points, Saturn, the closer resources are to the colony the better the position. the whole idea of colonies is to get away from the Earth and close to resources. a colony could not be supported from earth or even built from the earth.

 

7) Internal security.

 

I not sure what you mean, a colony tens or even hundreds of kilometers across would be very robust and difficult to really damage. Keeping nuclear weapons and really powerful chemical explosives from people should not be a big problem. I would think that people who wanted to colonize bad enough to travel to and help build these structures would probably not be looking to kill everyone in them. At first you might get people with an agenda that might be other than colonization but after generations lived and struggled to build ever bigger and better habitats this would be an easier problem to get a handle on. I am not talking about forcing people to go to these colonies, this would have to be a labor of love not a punishment for malcontents.

 

Before you set out on an expensive trip it helps to have a destination.

 

This true, the destination would be the solar system, the galaxy and the future!

[UncleAl]

What wall will stop a gram meteor traveling at 20 miles/sec relative? Shaped charge jets top off at 1 mile/sec strike velocity. "capable of piercing armor equivalent to 900 mm thickness." That is 35 inches. Kinetic energy = (mv^2)/2.

 

"Babylon 5 is five miles long and weighs 2.5 million tonnes."

 

The Space Scuttle boosts maximum 22 tonnes into low Earth orbit (derated for "safety"). At 100% Official capacity it would be 114,000 launches. Lose the idiot Space Scuttle and only use the engines. That gains 60 tonnes of payload. Call it 80 tonnes payload/launch for only 31,000 launches. One launch/week for 600 years. giggle.

 

The Saturn 5 boosted 127 tonnes into low Earth orbit at 1/3 the Space Scuttle's cost/gram (constant dollars). 20,000 launches. One launch /week for 380 years. giggle.

[Moontanman]

What wall will stop a gram meteor traveling at 20 miles/sec relative? Shaped charge jets top off at 1 mile/sec strike velocity. "capable of piercing armor equivalent to 900 mm thickness." That is 35 inches. Kinetic energy = (mv^2)/2.

 

"Babylon 5 is five miles long and weighs 2.5 million tonnes."

 

The Space Scuttle boosts maximum 22 tonnes into low Earth orbit (derated for "safety"). At 100% Official capacity it would be 114,000 launches. Lose the idiot Space Scuttle and only use the engines. That gains 60 tonnes of payload. Call it 80 tonnes payload/launch for only 31,000 launches. One launch/week for 600 years. giggle.

 

The Saturn 5 boosted 127 tonnes into low Earth orbit at 1/3 the Space Scuttle's cost/gram (constant dollars). 20,000 launches. One launch /week for 380 years. giggle.

 

First, meteor strikes will be a problem that will have to be worked on but you are assuming we will build with materials like solid metal and there is no comparing a shaped charge designed to penetrate with a small rock that will vaporise on impact with no directional component. Metal or even silicate foam reinforced with carbon Nano tubes several meters thick will make up the walls. Cables made of carbon nano tubes will hold the colony together like an endless suspension bridge. The outer rotating walls will be even more protected by the fact they will be rotating. A rotating object is much harder to penetrate than a stationary one. Ever try to shoot out a rotating tire by shooting the moving out side of the tread?Large meteors can be stopped by high frequency solid state lasers. Really large ones can be avoided by moving the colony out of the way. These problems are solvable, I will say again, no one can build a realistic colony by lifting materials from the surface of the Earth, even nuclear light bulb rockets that can lift the entire international space station and more in one launch would be totally inadequate. large colonies will have to be build from materials already in space, from asteroids, burnt out comets, ice moons of Saturn, the Lagrange points of Jupiter would be the great manufacturing sites, lots of all the materials you need and low energy orbits needed to transport anything. Get away from geocentric thinking, to colonize the solar system we will need to use the resources found already in space.

[UncleAl]

Metal or even silicate foam reinforced with carbon Nano tubes several meters thick will make up the walls.

 

Shaped charge penetration depth for concrete is double that of armor plate. Carbon unravels to atoms by about 4500 C - diamond, graphite, vitreous, fiber, nanotubes, whatever. In hydrodynamic deformation mode the major shielding consideration is mass/cm^2 (not per volume). Ductile vs. brittle failure can be balanced, hence Chobham armor. Explosively shaped projectiles - fast-traveling solid lumps - hole Chobham armor, hence the DoD's panic in Iraq when its glacis plates went all Swiss cheesy from munitions not much larger than your fist detonated 10 meters distant. The solution? Pull out the expensive tanks and substitute cheap Hummers as targets. The enemy then used buried artillery shells and land mines to do the Hummers.

 

Chobham armour - Wikipedia, the free encyclopedia

Not nearly good enough - weight vs. effectiveness - for gram meteors, including nanotube plus depleted uranium upgrades (density = 19 grams/cm^3) as described.

 

Get away from geocentric thinking, to colonize the solar system we will need to use the resources found already in space.

 

What transports labor? What does it breathe and eat? The Earth is differentiated by weathering and tectonics. Oxidizer is free and unlimited. The asteroid belt is random non-volatile star stuff. You can have all the nickel-iron you desire but not enough sunlight to melt it (intensity as 1/r^2). If you want copper for wires you are screwed, ditto limestone for cement, silicon for semiconductors, aluminum for beer cans... The moon doesn't have reduced metals at all nor does it have ore deposits.

 

Work out the distance then the Earth to target lightspeed delay. No real time conversation with the asteroid belt. Not nearly.

 

There is that little problem of cosmic radiation occasionally juiced by solar flares. The Earth's atmosphere at sea level is equal to 35.8 inches thickness of lead shielding. Work it out - 14.7 psi. Light element shielding won't stop hugely GeV protons. Heavy element shielding (g/cm^2 again) does pair formation thence 511 KeV photons, and neutrons from spallation. You need heavy elements to stop the photons but light elements to stop the neutrons. Everybody in Mir and ISS FUBAR gets radiation cataracts - and both are still shielded by the Earth's magnetosphere deflecting cosmic ray protons to the poles.

 

The only practical lunar colonization is tunnels about 30-50 feet under regolith against radiation and temperature. Nobody has volunteered lunar backhoes, robotic or manned. Explosives to excavate? You ride the bus, launch (major vibration) to soft touchdown. You need more work on the reduction to practice.

[Moontanman]

Shaped charge penetration depth for concrete is double that of armor plate. Carbon unravels to atoms by about 4500 C - diamond, graphite, vitreous, fiber, nano tubes, whatever. In hydrodynamic deformation mode the major shielding consideration is mass/cm^2 (not per volume). Ductile vs. brittle failure can be balanced, hence Chobham armor. Explosively shaped projectiles - fast-traveling solid lumps - hole Chobham armor, hence the DoD's panic in Iraq when its glacis plates went all Swiss cheesy from munitions not much larger than your fist detonated 10 meters distant. The solution? Pull out the expensive tanks and substitute cheap Hummers as targets. The enemy then used buried artillery shells and land mines to do the Hummers.

 

First a meteorite is not a shaped charge made to penetrate as far as possible. Say a dime sized meteor hits something, it's energy is does not cause a shaped charge type of explosion. The energy of impact simply vaporises a small crater in what ever it hits. The vapor doesn't have the penetrating power it's speed would suggest. It's very speed would hinder anything happening but a small crater. A rock foam layer a few meters thick would be able to take quite large meteor without the damage of a shaped charge. A shaped charge uses it's own casing to cause a high speed jet of metal vapor, a meteor doesn't have anything to direct it's vapor and the speed of impact is converted into heat not a directional spray of hot dense vapor. the idea is not stop the meteor but to have it expend it's energy as heat and only destroy a small area. something like ablative armor.

 

Chobham armour - Wikipedia, the free encyclopedia

Not nearly good enough - weight vs. effectiveness - for gram meteors, including nanotube plus depleted uranium upgrades (density = 19 grams/cm^3) as described.

 

This doesn't apply for the above mentioned reasons. Brute force isn't what will stop meteors. You use their own energy against them.

 

What transports labor? What does it breathe and eat? The Earth is differentiated by weathering and tectonics. Oxidizer is free and unlimited. The asteroid belt is random non-volatile star stuff. You can have all the nickel-iron you desire but not enough sunlight to melt it (intensity as 1/r^2). If you want copper for wires you are screwed, ditto limestone for cement, silicon for semiconductors, aluminum for beer cans... The moon doesn't have reduced metals at all nor does it have ore deposits.

 

Ore deposits are not likely in the asteroid belt or anywhere but on a planet. But the elements do occur there and with nuclear power huge amounts of metallic/rocky asteroids can be processed for everything in them. It has been estimated that even a one mile in diameter nickle/iron asteroid would contain enough metals such as platinum, gold, copper, and other heavy metal to make everyone on the earth rich. (not counting the cost of getting the object into earth orbit and processing.) since we don't want to move the metal anywhere to use it that will not be problem. More than enough trace metals can be processed from asteroids as well as hydrocarbons from such things as carbonaceous chonderites and water from old comet cores and small ice moons. Moving this stuff around will be easy since it doesn't have to move fast and can be moved around using minimum energy orbits. Much of the construction will be robotic in nature but people will have to be on site to direct the machines. Nuclear rockets are more than powerful enough to bring the first waves of workers but as the colonization technology matures much if not most of the workers will come from other colonies as their population expands. You have to think of it from the stand point of a slow process. How difficult would it be to transport the entire population of the new world from Europe in one shot. It would be easy to say it's impossible but as the colonies get more wide spread the population will increase on it's own. I am not talking about a one shot deal, this will be away of life and people will reproduce.

 

Work out the distance then the Earth to target lightspeed delay. No real time conversation with the asteroid belt. Not nearly.

 

I'm not sure what you mean by this, elaborate please.

 

There is that little problem of cosmic radiation occasionally juiced by solar flares. The Earth's atmosphere at sea level is equal to 35.8 inches thickness of lead shielding. Work it out - 14.7 psi. Light element shielding won't stop hugely GeV protons. Heavy element shielding (g/cm^2 again) does pair formation thence 511 KeV photons, and neutrons from spallation. You need heavy elements to stop the photons but light elements to stop the neutrons. Everybody in Mir and ISS FUBAR gets radiation cataracts - and both are still shielded by the Earth's magnetosphere deflecting cosmic ray protons to the poles

.

 

Radiation will be a problem, workers will have to be limited in how long they can work and where but farther from the sun will make these events (flares, magnetic storms) less powerful and charge fields and magnetic fields will help as the colonies are built but once they are built they will be big and thick enough to shield everyone from radiation. Mir and ISS are too small and thin to protect anyone from anything, their metal hulls actually make things worse from the by products of cosmic rays hitting metal.

 

The only practical lunar colonization is tunnels about 30-50 feet under regolith against radiation and temperature. Nobody has volunteered lunar backhoes, robotic or manned. Explosives to excavate? You ride the bus, launch (major vibration) to soft touchdown. You need more work on the reduction to practice.

 

Asteroids are big enough for tunnels to be dug to protect the workers from radiation. and nuclear power will be used to create intense magnetic fields and charge fields to protect workers.

[TheBigDog]

Modular and repairable. If you hit a pebble in space you need to minimize the affect on the ship and move on with life. Individually sustainable modular units lets a percentage of the ship be taken out without losing the ability to continue its mission.

 

Bill

[CraigD]

First a meteorite is not a shaped charge made to penetrate as far as possible. Say a dime sized meteor hits something, it's energy is does not cause a shaped charge type of explosion. The energy of impact simply vaporises a small crater in what ever it hits. The vapor doesn't have the penetrating power it's speed would suggest.

I believe MTman is thinking too intuitively in his comparison of meteors and explosives.

 

Shaped charges are explosive devices designed to overcome a fundamental shortcoming of simple, un-encased explosives: that their energy spreads from them in many directions. Though it’s uncommon to consider them so, the most common shaped charge devices in most peoples’ experience are small guns. The small amount of low explosive in a typical rifle cartridge, spread on an ordinary thin wood table and lit from the distance afforded by a long match, is harmless, while the same charge driving a bullet from a gun barrel readily penetrates the table.

 

A projectile, such as a small or large meteor, delivers all of its energy in a single direction. It is, essentially, the effective part of a shape charge, without all the less effective parts.

 

Our experience living in an atmosphere is that low-density “projectiles” such as puffs of gas or “soft” ones such as streams of water are less destructive than dense, hard ones such as bullets and arrows. However, in vacuum, such differences are less significant.

 

A rough approximation of the penetration of a meteor can be had by comparing the vaporization energy of a hemisphere of water to the kinetic energy of the projectile. This given the required thickness of armor [math]r[/math] to stop a meteor of mass [math]m[/math] and speed [math]v[/math] as:

[math]r = k v^\frac23 m^\frac13[/math]

where [math]k[/math] is a constant [math]k = \frac3{4 \pi 100 c_p}[/math]

where [math]c_p[/math] is the specific heat of water. For a range of masses from micrometeor to boat-size, and speeds from human running to the fastest observed meteoroids, [math]r[/math] in meters is

Mass      Speed (m/s)
(kg)          10      40     100     400    1000    4000   10000   40000   72000
.001      0.0004  0.0010  0.0018  0.0045  0.0083  0.0209  0.0385  0.0970  0.1435
.004      0.0006  0.0015  0.0028  0.0071  0.0132  0.0332  0.0611  0.1540  0.2279
.01       0.0008  0.0021  0.0038  0.0097  0.0179  0.0450  0.0829  0.2090  0.3093
.04       0.0013  0.0033  0.0061  0.0154  0.0284  0.0715  0.1317  0.3318  0.4909
.1        0.0018  0.0045  0.0083  0.0209  0.0385  0.0970  0.1787  0.4503  0.6663
.4        0.0028  0.0071  0.0132  0.0332  0.0611  0.1540  0.2837  0.7148  1.0577
1         0.0038  0.0097  0.0179  0.0450  0.0829  0.2090  0.3850  0.9701  1.4355
4         0.0061  0.0154  0.0284  0.0715  0.1317  0.3318  0.6111  1.5399  2.2787
10        0.0083  0.0209  0.0385  0.0970  0.1787  0.4503  0.8294  2.0900  3.0926
40        0.0132  0.0332  0.0611  0.1540  0.2837  0.7148  1.3166  3.3177  4.9092
100       0.0179  0.0450  0.0829  0.2090  0.3850  0.9701  1.7869  4.5028  6.6629
400       0.0284  0.0715  0.1317  0.3318  0.6111  1.5399  2.8366  7.1477 10.5767
1000      0.0385  0.0970  0.1787  0.4503  0.8294  2.0900  3.8498  9.7009 14.3547
40000     0.1317  0.3318  0.6111  1.5399  2.8366  7.1477 13.1662 33.1767 49.0925
100000    0.1787  0.4503  0.8294  2.0900  3.8498  9.7009 17.8693 45.0277 66.6287

This simple model assumes a perfectly ablative shield material. In reality, armor must resist complicated effects such as spalling, while material in a space station may need to retain structural integrity when penetrated or pitted, and must resist structural failure due to cracking.

the idea is not stop the meteor but to have it expend it's energy as heat and only destroy a small area. something like ablative armor.

At common meteor speeds, any material (with the exception of some sort of exotic, beyond-current-material-technology substance like neutronium, that could elastically “bounce” the remnants of a collided meteor with little loss of total kinetic energy), is ablative.

Brute force isn't what will stop meteors. You use their own energy against them.

I don’t think you can use an impactor’s energy against it – even such mundane projectiles as armor piercing bullets and shells – which have maximum speeds of around 1000 m/s - are heated into a liquid and/or gas state on impact, yet are still effective penetrators.

 

Rather than attempting to armor a giant spacecraft, you could follow Bill’s advice about “just moving on with life [aboard a spacecraft]”, and make its skin as thin as structurally practical while providing adequate radiation shielding, accepting that an occasional meteor will cleanly penetrate it. Unless an inhabitant is unlucky enough to be in its path, or the designer or maintainer foolish enough to have a dusty, high-oxygen, explosive atmosphere, a layer of suitable dirt and glop should be able to quickly seal even a fairly large hole, making a meteor penetration a potentially loud and spectacular, but survivable, event.

 

I can’t do justice to the many good points raised in this thread in a single post, but want to just summarily comment on one:

But the elements do occur there and with nuclear power huge amounts of metallic/rocky asteroids can be processed for everything in them.

Details aside, this is, IMHO, the most important observation concerning the making of space colonies. As Uncle Al describes, the many costs of lifting materials from Earth are likely prohibitive for building large spacecraft with such materials, so such construction necessarily must use what’s already floating freely in space.

 

I’d take it a step further, and suggest that it’ll also be necessary to use energy already freely available in space. By far, the most abundant energy source there is sunlight.

 

Though the details are … well … detailed, consider this “first, build a factory-making factory” scenario:

• A Earth-built spacecraft rendezvous with an asteroid..
  
• Using a large earth-built Fresnel lens, asteroid material is smelted into useful engineering material
  
• This material is fabricated into more Fresnel lenses, smelters, and fabricators.
  
• Repeat
  

Though the engineering challenges of such a scheme are great, it is not thwarted by a shortage of sunlight and asteroid material.

[Thunderbird]

What this comes down to simple economics. The amount of energy, time, and expense for such a venture would greatly out weigh any returns or benefits.

 

I do not see how this would be solving population problems for one thing. The amount of energy and resources to transport and keep one human in space would be in the millions annually.

 

You could build cites under, or on the sea cheaper.

You could mine resources from or own earth cheaper, we have no shortage of minerals.

You can distil sea water cheaper.

You could turn deserts into farmland cheaper.

You could turn technology eco friendly cheaper.

all of these alternatives combined would cost much less in resources to feed, house burgeoning populations in the far future than the cost it would take to maintain even a small city in space, not to mention the quality of life that would be enjoyed by an earthling , compared to a human living in the contained artificial environment.

 

I am sorry I just do not see this as a viable solution to anything. Unless it was financed in the a private sector for individuals who could afford the novelty of vacation in space. It would cost billions just to do it on a very small scale, but it could possibly expand from there. Keep in mind however the cost for a government agency provided by tax payers under the guise of the benefiting mankind's future will never be a option. It would only be a select few that would ever get to go, and would never make ethical sense for the common man to pay for it.

[UncleAl]

You are arguing flea farts in a hurricane. Matthew 7:4 "Or how can you say to your brother, 'Let me take the speck out of your eye,' and behold, the log is in your own eye."

 

If you need one truly huge launch/week for 600 years to orbit your whole thingie, it matters not what your thingie is. If you must commute to the asteroid belt, you won't. If you get it all hung together in place - no matter where and what it is - and it doesn't pay for its $quadrillion self, it isn't.

 

If you cannot solve the propulsion problem you have nothing in space. You cannot, you don't. 1960 to 1970 a handful of unrepentent Nazis - starting with a V-2, slide rules, and immigrant machinists - went to the moon big time for $135 million/pop. In 2008 NASA - with the Space Scuttle, 10240 processor Columba supercomputer, CAD/CAM/CNC machining - cannot get back to the moon with $1.5 billion launches. Do you comprehend the real world problems?

 

Building a skyscraper starting with its fifth floor is unrealistic. Design a 1000 tonne payload Earth to moon heavy lifter and we'll talk.

 

NASA HATE CRIMES, II

[Moontanman]

You are arguing flea farts in a hurricane. Matthew 7:4 "Or how can you say to your brother, 'Let me take the speck out of your eye,' and behold, the log is in your own eye."

 

If you need one truly huge launch/week for 600 years to orbit your whole thingie, it matters not what your thingie is. If you must commute to the asteroid belt, you won't. If you get it all hung together in place - no matter where and what it is - and it doesn't pay for its self, it isn't.

 

If you cannot solve the propulsion problem you have nothing in space. You cannot, you don't. 1960 to 1970 a handful of unrepentent Nazis - starting with a V-2, slide rules, and immigrant machinists - went to the moon big time for $135 million/pop. In 2008 NASA - with the Space Scuttle, 10240 processor Columba supercomputer, CAD/CAM/CNC machining - cannot get back to the moon with $1.5 billion launches. Do you comprehend the real world problems?

 

Building a skyscraper starting with its fifth floor is unrealistic. Design a 1000 tonne payload Earth to moon heavy lifter and we'll talk.

 

NASA HATE CRIMES, II

 

1000 ton launch capability? No problem

 

http://nextbigfuture.com/2007/07/gaseous-core-nuclear-design-liberty.html

 

Again you are assuming we would do this all at once with launches from the earth, only the barest and smallest part would come from the earth at the start. virtually all the materials and would come from space not the earth. as for paying for it's self did the first colonies to North America pay fro themselves? what if the queen of Spain had said the new world was too far away and to transport millions of people would not be practical in any sense of the word? it will be a slow process not a one shot deal.

[Moontanman]

A more complete article about nuclear light bulb rockets.

 

BRUCE BEHRHORST ARTICLE LIST

[Moontanman]

What this comes down to simple economics. The amount of energy, time, and expense for such a venture would greatly out weigh any returns or benefits.

 

Not true, simply spreading the human race out from the Earth has the priceless benefit of allowing the human race to survive a planetary disaster.

 

I do not see how this would be solving population problems for one thing. The amount of energy and resources to transport and keep one human in space would be in the millions annually.

 

Only if you assume the energy and resources had to come from the earth.

 

You could build cites under, or on the sea cheaper.

 

Who would want to live in a tin can under the sea?

 

You could mine resources from or own earth cheaper, we have no shortage of minerals.

 

While this can be debated why would you want to continue to destroy the environment to mine minerals on the Earth when the same minerals are available from space in much larger quantities and cheaper. it doesn't cost much to bring something to the Earth from space.

 

You can distil sea water cheaper.

 

What does this have to do with space colonization?

 

You could turn deserts into farmland cheaper.

 

Maybe, but there is only so much desert and turning it to farm land destroys the desert as a unique environment and desert cannot be farmed with out other environmental costs. Desert has been turned into toxic waste land many times when irrigation is used to grow crops. A bad idea almost always in the long run.

 

You could turn technology eco friendly cheaper.

 

No matter how Eco friendly technology is it still doesn't solve all the problems of pollution, mining, disaster, lack of space (too many people), war, poverty, the list goes on. Space colonies can be made as the population expands always staying ahead of the curve. If disaster strikes it cannot strike all the colonies at once but disaster can strike the whole earth at once.

all of these alternatives combined would cost much less in resources to feed, house burgeoning populations in the far future than the cost it would take to maintain even a small city in space, not to mention the quality of life that would be enjoyed by an earthling , compared to a human living in the contained artificial environment.

 

You still cannot get away from the idea these colonies would be somehow stifling tin cans. The inside would be like living in a glacier valley a couple miles across and several miles long. Lots of space both for people and nature. Eventually the Earth will be far more crowded than these colonies would be. as fro the cost of maintaining them, again I'll say the Earth will not support these colonies, they will support themselves from resources at hand not from resources brought from the earth. I can see thousands of colonies in the Lagrange orbits of Jupiter using the huge number of asteroids and ice chunks orbiting there. Once established these colonies can build their own copies of themselves from materials at hand and from personal at hand as well. No support from the earth will necessary in the long term.

 

anything. Unless it was financed in the a private sector for individuals who could afford the novelty of vacation in space. It would cost billions just to do it on a very small scale, but it could possibly expand from there. Keep in mind however the cost for a government agency provided by tax payers under the guise of the benefiting mankind's future will never be a option. It would only be a select few that would ever get to go, and would never make ethical seI am sorry I just do not see this as a viable solution to nse for the common man to pay for it.

 

You are still looking at this like it is some kind of short term venture financed by the Earth for all eternity. This will be the establishment of independent worlds with their own economy, governments, and reasons for living. Not a space station that has to be supplied from the earth and existing at the whims of the earth. Once the infrastructure of this space civilization is established it becomes self sustaining and separate from the earth.

[UncleAl]

Gaseous core nuclear design, the Liberty Ship

Remember the crapstorm over Cassini's Pu-238 thermoelectric generators? The world will not tolerate Florida becoming Chernoble, ditto all points downwind. Where do you do the second launch, either way?

 

Nuclear rocket propulsion! HA HA HA! Welcome to 1950. You got clever ways to shield it without adding mass? Nuclear airplanes, nuclear cars, nuclear tricycles! First, we kill all the engineers...

Why is better for people to die doing mundane matters as part of mundane lives than to risk dieing trying to achieve something audacious...

Everybody has something worth dying for. What have you got that is worth living for?

Chemical rockets are likely fancy balloons filled with fuel.

Uncle Al suggests you read a reference before posting it. Have you ever designed a rocket bell? They have different aspect ratios for in-atmosphere and out-of-atmosphere operation.