Orion project question
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kunkmiester
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Orion project question
If one made a "propulsion module" using a device based on a bomb pumped generator pulsing a fusion reactor of sorts, thus only deriving it's power from the deuterium(maybe D-T) in the primary and secondary, would you have to worry about HEMP when an Orion vehicle using them goes through the upper atmosphere?
Evil is evil, no matter how small
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kunkmiester
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I recall it being gamma rays stripping electrons out of the air. These moving along the field lines makes the current that produces the EMP. I'm not sure how many gamma rays you'd get out of a D-D or D-T bomb, or if the neutrons you'd surely get would be enough.
Orion would be one of the many wonderful uses of fission free nuclear bombs, provided the launch doesn't destroy the tech system we use.
Orion would be one of the many wonderful uses of fission free nuclear bombs, provided the launch doesn't destroy the tech system we use.
Evil is evil, no matter how small
Firing off a nuclear explosion in or just above the atmosphere would certainly produce an EMP. I have measured what amounts to EMP from a chemical explosion of a pound or two of C4 ... EMP can be produced by anything energetic enough to make ions move fast. Direction of the exhaust would have a great deal to do with it. Exhaust directed down would have more effect.
But it won't happen, and the reasons are at least as much political as technical. Orion is a tough enough sell to people opposed to nuclear weapons (even if called propulsive devices) in space. In the atmosphere or in LEO is a non-starter. If Orion ever flys, it will be a deep space device.
"Teensy little nukes," to quote David Brin in Startide Rising, would help diffuse the objection.
But it won't happen, and the reasons are at least as much political as technical. Orion is a tough enough sell to people opposed to nuclear weapons (even if called propulsive devices) in space. In the atmosphere or in LEO is a non-starter. If Orion ever flys, it will be a deep space device.
"Teensy little nukes," to quote David Brin in Startide Rising, would help diffuse the objection.
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CaptainBeowulf
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kunkmiester
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The propulsion module design in question doesn't use uranium or plutonium. This is the big question for the thread, since it's certain types of radiation that produce most of the affect for a HEMP, and without those radiations, the affect would be much reduced, perhaps to the point of being harmless as the ship passes through the zone where the initiations would produce the HEMP effect.
The other advantage of course is that without uranium or plutonium in the bomb, the fallout changes nature and amount to about as harmless as you can hope for.
These would be "teensy little nukes" for the most part, since I'd imagine the core device wouldn't produce more than several tons equivalent of fusion power. This device would likely set off a secondary designed to produce most of the yield above a few dozen tons of TNT.
The other advantage of course is that without uranium or plutonium in the bomb, the fallout changes nature and amount to about as harmless as you can hope for.
These would be "teensy little nukes" for the most part, since I'd imagine the core device wouldn't produce more than several tons equivalent of fusion power. This device would likely set off a secondary designed to produce most of the yield above a few dozen tons of TNT.
Evil is evil, no matter how small
One of my SF-writing buddies recently quoted another SF writer. Alas, I'm away from my files and can't look it up at the moment. The gist of it is that if humanity survives for as long as we like to think we will (tens of thousands of years being only a good start), they will look way back into their historical dustbin and realize that only in the first little sliver of recorded human history did the word "ship" refer to a craft designed for water.
We're at a point in our history where we are thinking about ships meaning something besides craft designed for water, and we are preoccupied with figuring out how to get up there. But once established in space, the question is more likely to be why we should bother to come back down into gravity wells at the bottom of which is a treacherous atmosphere. This business of launching from Earth to LEO is only a problem if we are on Earth.
It is a leap we need to make. I think I want cleaner than either NERVA or Orion. Hydrogen and oxygen are honestly not all that bad a chemical fuel system ... 460 seconds Isp. NERVA only gets you to around 850 seconds. Fuel cost is not presently the real problem. The high costs of launch are elsewhere. Increased Isp's real benefit is a better payload fraction so those other excessive costs pay off better, but I think we can get there with chemical fuels by economical mass production and efficient launches of Big Dumb Boosters even if we can't find a "nuclear option".
The the trick is to get up there and stay up there.
We're at a point in our history where we are thinking about ships meaning something besides craft designed for water, and we are preoccupied with figuring out how to get up there. But once established in space, the question is more likely to be why we should bother to come back down into gravity wells at the bottom of which is a treacherous atmosphere. This business of launching from Earth to LEO is only a problem if we are on Earth.
It is a leap we need to make. I think I want cleaner than either NERVA or Orion. Hydrogen and oxygen are honestly not all that bad a chemical fuel system ... 460 seconds Isp. NERVA only gets you to around 850 seconds. Fuel cost is not presently the real problem. The high costs of launch are elsewhere. Increased Isp's real benefit is a better payload fraction so those other excessive costs pay off better, but I think we can get there with chemical fuels by economical mass production and efficient launches of Big Dumb Boosters even if we can't find a "nuclear option".
The the trick is to get up there and stay up there.
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CaptainBeowulf
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I think, even at our current technological level, if we got a critical mass of manufacturing capability and habitat space up there it would become self-sustaining and then profitable.
To use a business analogy, the problem is start-up costs.
Redesign of stuff to work in zero-g/vacuum is quite doable, but still costs money. You need to be able to, say, smelt metal and cast components at a Lagrange point from materials you mine from asteroids.
Then you have to get it there. Even a shuttle derived big dumb booster is pretty dang expensive. And, before you could get a self-sustaining capability, you'd probably have to launch tens of thousands of metric tons of equipment from the surface of the earth. Amongst other things, you'd need:
- Space tugs for grabbing and moving small asteroids
- Mining equipment for mining on the moon and asteroids
- Smelters
- Fabrication plants for casting components
- Mining equipment specialized for mining or capturing ice/water
- Equipment for breaking water down into hydrogen and oxygen fuel
- Storage tanks for all sorts of stuff
- Enough habitation units fabricated on earth to house the several hundred people who would make up the "start-up staff" to operate all these things
- An initial stock of hydroponic facilities to grow food, before you could manufacture more
- Spaceplanes or capsules to move back and forth from Earth's surface while you do all this stuff
- Probably both compact nuclear reactors and massive photovoltaic arrays made on earth to provide enough power at the start
- Etc.
Once the critical base is established, they could make all the above themselves. Then it would be a comparative cakewalk to go on to the rest of the solar system, and to start building huge space habitat cities (those ring shaped things) that could house hundreds of thousands of people, etc.
Where does profit come in? One example is that alloys cast into shapes in space would probably be better than those cast on earth - no atmospheric contaminants, no subtle influence of gravity on the molecular lattice as it sets. You could probably drop components back down to the planet and sell them at a premium.
However, it raises another problem. If you stop and think about this as a government policy analyst, what are you creating when you do the above? Basically, a competitor. Can you indefinitely enforce sovereignty over "your" space colonists? No more than Britain could control the 13 colonies. Eventually, they're going to go their own way. They have more room to grow than you do on earth. They have access to more resources. They can make products you can't on earth, and sell them at profit. Their economy could grow larger than yours. A "spacer" confederacy in the solar system could become the local superpower, able to dictate terms to the old surface-locked powers on earth.
Has any superpower in history really invested a gigantic portion of its GDP over a period of decades to create a potential rival superpower?
There's really nothing in it for, say, the U.S. or China to create a self-sustaining space civilization. There are only the arguments of space enthusiasts and a few scientists. We like to present the very cogent argument that life on earth could be destroyed by a cataclysm, such as an asteroid strike, and that we shouldn't put all our eggs in one basket. For species survival, we should establish self-sustaining colonies off-world.
However, governments typically only react to crises. Your typical government analyst is going to say: "What are the chances that we'll really get a catastrophic asteroid hit in our lifetimes? What are the chances that we'll really get a runaway greenhouse effect on earth? What are the chances we'll really get crazy vulcanism? In the next thousand years? Right. One in a very large number."
Politicians can buy votes by spending money on more mundane things right now. Government departments have their own existing pet projects to channel money into. Building a civilization in space appears at best unnecessary and, if they were to think it through, a possible threat to their particular special interests.
So, we'll never get the huge start up money we would need at our current technological level. That's why we need some technological breakthroughs to access space: it needs to become cheap enough to get up there that the average people can do it themselves, and the world's governments won't be able to stop them.
To use a business analogy, the problem is start-up costs.
Redesign of stuff to work in zero-g/vacuum is quite doable, but still costs money. You need to be able to, say, smelt metal and cast components at a Lagrange point from materials you mine from asteroids.
Then you have to get it there. Even a shuttle derived big dumb booster is pretty dang expensive. And, before you could get a self-sustaining capability, you'd probably have to launch tens of thousands of metric tons of equipment from the surface of the earth. Amongst other things, you'd need:
- Space tugs for grabbing and moving small asteroids
- Mining equipment for mining on the moon and asteroids
- Smelters
- Fabrication plants for casting components
- Mining equipment specialized for mining or capturing ice/water
- Equipment for breaking water down into hydrogen and oxygen fuel
- Storage tanks for all sorts of stuff
- Enough habitation units fabricated on earth to house the several hundred people who would make up the "start-up staff" to operate all these things
- An initial stock of hydroponic facilities to grow food, before you could manufacture more
- Spaceplanes or capsules to move back and forth from Earth's surface while you do all this stuff
- Probably both compact nuclear reactors and massive photovoltaic arrays made on earth to provide enough power at the start
- Etc.
Once the critical base is established, they could make all the above themselves. Then it would be a comparative cakewalk to go on to the rest of the solar system, and to start building huge space habitat cities (those ring shaped things) that could house hundreds of thousands of people, etc.
Where does profit come in? One example is that alloys cast into shapes in space would probably be better than those cast on earth - no atmospheric contaminants, no subtle influence of gravity on the molecular lattice as it sets. You could probably drop components back down to the planet and sell them at a premium.
However, it raises another problem. If you stop and think about this as a government policy analyst, what are you creating when you do the above? Basically, a competitor. Can you indefinitely enforce sovereignty over "your" space colonists? No more than Britain could control the 13 colonies. Eventually, they're going to go their own way. They have more room to grow than you do on earth. They have access to more resources. They can make products you can't on earth, and sell them at profit. Their economy could grow larger than yours. A "spacer" confederacy in the solar system could become the local superpower, able to dictate terms to the old surface-locked powers on earth.
Has any superpower in history really invested a gigantic portion of its GDP over a period of decades to create a potential rival superpower?
There's really nothing in it for, say, the U.S. or China to create a self-sustaining space civilization. There are only the arguments of space enthusiasts and a few scientists. We like to present the very cogent argument that life on earth could be destroyed by a cataclysm, such as an asteroid strike, and that we shouldn't put all our eggs in one basket. For species survival, we should establish self-sustaining colonies off-world.
However, governments typically only react to crises. Your typical government analyst is going to say: "What are the chances that we'll really get a catastrophic asteroid hit in our lifetimes? What are the chances that we'll really get a runaway greenhouse effect on earth? What are the chances we'll really get crazy vulcanism? In the next thousand years? Right. One in a very large number."
Politicians can buy votes by spending money on more mundane things right now. Government departments have their own existing pet projects to channel money into. Building a civilization in space appears at best unnecessary and, if they were to think it through, a possible threat to their particular special interests.
So, we'll never get the huge start up money we would need at our current technological level. That's why we need some technological breakthroughs to access space: it needs to become cheap enough to get up there that the average people can do it themselves, and the world's governments won't be able to stop them.
While I agree, I feel you have it slightly backwards. I think it will become profitable, then self sustaining.CaptainBeowulf wrote:I think, even at our current technological level, if we got a critical mass of manufacturing capability and habitat space up there it would become self-sustaining and then profitable.
Exactly, Cap'n ... what did Spain get out of colonizing the New World?
Yeah, they pillaged some gold and silver, and got some trade out of it, but mostly they found a place for people to live and prosper. That prosperity stayed, for the most part, in the New World.
That's the dirty litte secret of space. Anyone hoping to find something valuable to ship back is missing the real story. Yet that is the most obvious motive for going.
What we get is an eventual human diaspora. Presuming that does not trigger some other species to kill us before we multiply (a common enough SF theme), it virtually assures that very long history where we forget about ships on water.
Yeah, they pillaged some gold and silver, and got some trade out of it, but mostly they found a place for people to live and prosper. That prosperity stayed, for the most part, in the New World.
That's the dirty litte secret of space. Anyone hoping to find something valuable to ship back is missing the real story. Yet that is the most obvious motive for going.
What we get is an eventual human diaspora. Presuming that does not trigger some other species to kill us before we multiply (a common enough SF theme), it virtually assures that very long history where we forget about ships on water.
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CaptainBeowulf
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Yup, that's the real point. The one I want to see as well. I don't think government will get us there.
I support keeping a shuttle derived heavy lift launch vehicle right now because it's the best short to medium term solution. It can allow us to do things like a terrestrial planet finder telescope. It will allow a replacement space station, maybe a station at a lagrange point, maybe a few more moon missions. In theory it could get us to Mars, but I doubt any government will actually, when it comes down to it, end up spending the money over a period of time that would be needed for a sustained Mars mission.
What interests me most is the the medium to long term technologies that will render that SDHLV technologically and economically redundant.
Which comes first, profitable or self sustaining? I actually think it could be done either way.
If we make certain kinds of working fusion reactor, then helium-3 mining on the moon might become profitable without building support infrastructure up there.
On the other hand, I can't really see making a good return on investment on mining, say, one asteroid. You have to send up a whole lot of stuff to go grab it, bring it into a safe orbit, grind it up, package the ore or manufacture it into the alloys you want, and then bring that product back down.
But, if you reprocess a couple of asteroids into infrastructure in orbit or at a Lagrange point, you have what you need in place to go get more. (I'm assuming here you also make fuel from ice found on them, or from a comet you grab, or from ice on the moon.)
At that point, you start mining more stuff and sending it back to earth with minimum need to launch additional materials from earth. The only launches you need are for crew rotation and perhaps small specialty which could be reasonably carried on a compact LV. At that point you start to make ROI.
I guess there's the whole space tourism industry idea as well. If it works, it will be an example of profitable before self-sustaining. At this point I think the jury's still out. The next ten to fifteen years should reveal whether space tourism is a viable business model.
Satellite communications and observation is obviously already a profitable industry, but the margins aren't very large. They certainly aren't large enough to give the companies involved enough cash flow to experiment with anything larger than a Delta IV heavy, or to go beyond orbit. So it's a dead end so far as developing a self-sustaining spacefaring capability goes.
I support keeping a shuttle derived heavy lift launch vehicle right now because it's the best short to medium term solution. It can allow us to do things like a terrestrial planet finder telescope. It will allow a replacement space station, maybe a station at a lagrange point, maybe a few more moon missions. In theory it could get us to Mars, but I doubt any government will actually, when it comes down to it, end up spending the money over a period of time that would be needed for a sustained Mars mission.
What interests me most is the the medium to long term technologies that will render that SDHLV technologically and economically redundant.
Which comes first, profitable or self sustaining? I actually think it could be done either way.
If we make certain kinds of working fusion reactor, then helium-3 mining on the moon might become profitable without building support infrastructure up there.
On the other hand, I can't really see making a good return on investment on mining, say, one asteroid. You have to send up a whole lot of stuff to go grab it, bring it into a safe orbit, grind it up, package the ore or manufacture it into the alloys you want, and then bring that product back down.
But, if you reprocess a couple of asteroids into infrastructure in orbit or at a Lagrange point, you have what you need in place to go get more. (I'm assuming here you also make fuel from ice found on them, or from a comet you grab, or from ice on the moon.)
At that point, you start mining more stuff and sending it back to earth with minimum need to launch additional materials from earth. The only launches you need are for crew rotation and perhaps small specialty which could be reasonably carried on a compact LV. At that point you start to make ROI.
I guess there's the whole space tourism industry idea as well. If it works, it will be an example of profitable before self-sustaining. At this point I think the jury's still out. The next ten to fifteen years should reveal whether space tourism is a viable business model.
Satellite communications and observation is obviously already a profitable industry, but the margins aren't very large. They certainly aren't large enough to give the companies involved enough cash flow to experiment with anything larger than a Delta IV heavy, or to go beyond orbit. So it's a dead end so far as developing a self-sustaining spacefaring capability goes.
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kunkmiester
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Some of this is actually what I'd intend to do with it. I'm running with this in a sci-fi story, but the real world wouldn't stop it except politically.
Space infrastructure is a chicken-egg problem. If you have an Orion drive, you can solve it all at once. The original designers were thinking million-ton payloads would be the low end of what's possible. If you can launch a million tons, you can launch a Bernal Sphere, or other "smaller" space habitat. This would be your primary living quarters, your manufacturing facilities, space docks already loaded down with space ships of all types--
You get some chickens AND eggs up there at once. Falcon 9 should be plenty for lifting people, though you'd want a capsule design for more than 7 people I'd think. And the business model isn't hard either--a corporation runs it, collecting rent for maintenance and such, renting out living space, working space, ships, whatever. Whoever gets up there can rent a spot/ship and as long as they can provide some sort of rent to keep the place going, they won't care. This wouldn't be too much different than other large buildings that are owned by a company that rents out space.
And countries WOULD do this if they had any way to get away with it. It's not just economic, IIRC having colonies in the New World was a bit of a pride point for most Europeans. At the same time, talking about economic and political competitors is kind of silly. Sure, the US fought Britain for independence, but 90% of the British Empire didn't have to fire a shot. A colony model might work better at first, but at some point you would switch to a model much like the British Commonwealth to allow peaceful independence that allow beneficial trade to continue while allowing a culturally drifting populace to go their own way.
Space infrastructure is a chicken-egg problem. If you have an Orion drive, you can solve it all at once. The original designers were thinking million-ton payloads would be the low end of what's possible. If you can launch a million tons, you can launch a Bernal Sphere, or other "smaller" space habitat. This would be your primary living quarters, your manufacturing facilities, space docks already loaded down with space ships of all types--
You get some chickens AND eggs up there at once. Falcon 9 should be plenty for lifting people, though you'd want a capsule design for more than 7 people I'd think. And the business model isn't hard either--a corporation runs it, collecting rent for maintenance and such, renting out living space, working space, ships, whatever. Whoever gets up there can rent a spot/ship and as long as they can provide some sort of rent to keep the place going, they won't care. This wouldn't be too much different than other large buildings that are owned by a company that rents out space.
And countries WOULD do this if they had any way to get away with it. It's not just economic, IIRC having colonies in the New World was a bit of a pride point for most Europeans. At the same time, talking about economic and political competitors is kind of silly. Sure, the US fought Britain for independence, but 90% of the British Empire didn't have to fire a shot. A colony model might work better at first, but at some point you would switch to a model much like the British Commonwealth to allow peaceful independence that allow beneficial trade to continue while allowing a culturally drifting populace to go their own way.
Evil is evil, no matter how small
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CaptainBeowulf
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The thing is, the British Empire morphed into the Commonwealth in part because of the example of the U.S. I think the bureaucrats in Whitehall realized that you might eventually get reruns of 1776 in Canada, Australia and New Zealand. At the beginning of the 20th century the Boers put up quite a bit of resistance to direct British control. As for the other primarily ethnically non-British colonies, the spread of nationalism meant that wars of national independence would happen sooner or later.
However, I think that the general public consciousness has now forgotten that period, and so the clock has been reset, so to speak. (Americans, of course, celebrate independence day and read about the importance of democracy and overthrowing tyrants in their school history textbooks, but I don't think the general public understands the historical context of that time anymore.)
Why did 1776 happen in the first place? Basically, Parliament and the government bureaucracy saw the Colonies as their possessions. They had fought wars to defeat the French, Dutch and others in the New World. They had invested a great deal, and subsidized the creation of the Colonies. Joint stock companies headquartered in London owned a lot of stuff in the Colonies. Ethnically, the Colonials were primarily British. There were plenty of Dutch, Germans, French etc., but then again, there was always a lot of population movement in northwestern Europe. There were plenty of people in Britain who were ethnically part French, part Dutch, part German etc., within their known ancestry.
(Of course the ancient Celtic Britons were related to the Celts of Gaul, Iberia and northern Italy, then a bit of Roman was mixed into all of them, and finally the Anglo-Saxon migration and the Viking settlement in the Danelaw had added a large amount of Germanic... but I don't think most people were really aware of that distant history.)
Basically, the majority of the representatives in Parliament were unable to adjust their world view to see the demands of the Colonists as legitimate. There were dissenting views. IIRC Pitt and the opposition party at the time of the American War of Independence were against fighting the Americans. There were also some petitions which garnered tens of thousands of signatures between 1775 and 1780 against fighting the Colonies. Nonetheless, the prevailing of much of the elite was that Britain had created the Colonies, and so it had an inherent right to control them.
George III's attitude, of course, reinforced this position. But it was there anyway.
I suspect that today's U.S. or China would view any space infrastructure subsidized by their governments and built and launched by corporations headquartered in their territories with the same attitude. That infrastructure would be "theirs." People living in it demanding independence essentially would be perceived as rebels or corporate thieves.
In addition, there's the whole military aspect. Space is the ultimate military high ground. An independent spacefaring nation in the solar system would occupy that high ground, and could fire stuff down at earth to get compliance from the planet's governments. Think, for example, of the "rods from god" systems we already have conceptualized (automated weapons platforms which can fire tungsten rods from orbit at targets on earth.) The superpowers' military forces and politicians would be loathe to cede independence to a new entity which would be so well-placed militarily.
I highly doubt anyone in the government thinks this way right now. However, as space based stuff becomes more self-sustaining, the warning bells might start ringing. That could lead to the major governments actually attempting to drastically and artificially restrict further development in space. They would want relatively small populations of government employees (ie. NASA and air force personnel) who would be rotated back to the Earth's surface regularly in order to ensure continued political loyalty.
(This actually has a parallel in U.S. history as well: Britain wanted to restrict European settlement to east of the Appalachians. It wanted the west to remain an area of resource exploitation - primarily furs and timber - which were generally harvested and traded to British merchant firms by native tribes with whom treaties had been signed. As late as the war of 1812 Britain was still trying to some extent to block U.S. expansion westward.)
So, in the short to medium term (basically the next several decades) I could see a renewed space race between the U.S. and China for national pride reasons. The E.U. and Russia would also be involved, but probably as secondary players. India might also get seriously involved at some point.
However, I think there would be a point at which they would start to rein things in. At that point, the only way to continue to develop a true spacefaring civilization would be for access to space to be cheap enough that a genuine mass migration would get underway.
Now, other changes could happen as well. It might be that the major world powers will eventually become more cooperative, and would be willing to create a new space nation with representation at the U.N. There would be some sort of non-aggression pact between all the surface powers with the tech level to launch stuff into space, and the space nation(s). This might be combined with some sort of further collective agreement to pool money to send out interstellar ships, and seed other star systems with new human nations. This is the sort of scenario I would prefer... but given human history, it's at least a 50% chance that you would get the conflict-ridden model instead.
However, I think that the general public consciousness has now forgotten that period, and so the clock has been reset, so to speak. (Americans, of course, celebrate independence day and read about the importance of democracy and overthrowing tyrants in their school history textbooks, but I don't think the general public understands the historical context of that time anymore.)
Why did 1776 happen in the first place? Basically, Parliament and the government bureaucracy saw the Colonies as their possessions. They had fought wars to defeat the French, Dutch and others in the New World. They had invested a great deal, and subsidized the creation of the Colonies. Joint stock companies headquartered in London owned a lot of stuff in the Colonies. Ethnically, the Colonials were primarily British. There were plenty of Dutch, Germans, French etc., but then again, there was always a lot of population movement in northwestern Europe. There were plenty of people in Britain who were ethnically part French, part Dutch, part German etc., within their known ancestry.
(Of course the ancient Celtic Britons were related to the Celts of Gaul, Iberia and northern Italy, then a bit of Roman was mixed into all of them, and finally the Anglo-Saxon migration and the Viking settlement in the Danelaw had added a large amount of Germanic... but I don't think most people were really aware of that distant history.)
Basically, the majority of the representatives in Parliament were unable to adjust their world view to see the demands of the Colonists as legitimate. There were dissenting views. IIRC Pitt and the opposition party at the time of the American War of Independence were against fighting the Americans. There were also some petitions which garnered tens of thousands of signatures between 1775 and 1780 against fighting the Colonies. Nonetheless, the prevailing of much of the elite was that Britain had created the Colonies, and so it had an inherent right to control them.
George III's attitude, of course, reinforced this position. But it was there anyway.
I suspect that today's U.S. or China would view any space infrastructure subsidized by their governments and built and launched by corporations headquartered in their territories with the same attitude. That infrastructure would be "theirs." People living in it demanding independence essentially would be perceived as rebels or corporate thieves.
In addition, there's the whole military aspect. Space is the ultimate military high ground. An independent spacefaring nation in the solar system would occupy that high ground, and could fire stuff down at earth to get compliance from the planet's governments. Think, for example, of the "rods from god" systems we already have conceptualized (automated weapons platforms which can fire tungsten rods from orbit at targets on earth.) The superpowers' military forces and politicians would be loathe to cede independence to a new entity which would be so well-placed militarily.
I highly doubt anyone in the government thinks this way right now. However, as space based stuff becomes more self-sustaining, the warning bells might start ringing. That could lead to the major governments actually attempting to drastically and artificially restrict further development in space. They would want relatively small populations of government employees (ie. NASA and air force personnel) who would be rotated back to the Earth's surface regularly in order to ensure continued political loyalty.
(This actually has a parallel in U.S. history as well: Britain wanted to restrict European settlement to east of the Appalachians. It wanted the west to remain an area of resource exploitation - primarily furs and timber - which were generally harvested and traded to British merchant firms by native tribes with whom treaties had been signed. As late as the war of 1812 Britain was still trying to some extent to block U.S. expansion westward.)
So, in the short to medium term (basically the next several decades) I could see a renewed space race between the U.S. and China for national pride reasons. The E.U. and Russia would also be involved, but probably as secondary players. India might also get seriously involved at some point.
However, I think there would be a point at which they would start to rein things in. At that point, the only way to continue to develop a true spacefaring civilization would be for access to space to be cheap enough that a genuine mass migration would get underway.
Now, other changes could happen as well. It might be that the major world powers will eventually become more cooperative, and would be willing to create a new space nation with representation at the U.N. There would be some sort of non-aggression pact between all the surface powers with the tech level to launch stuff into space, and the space nation(s). This might be combined with some sort of further collective agreement to pool money to send out interstellar ships, and seed other star systems with new human nations. This is the sort of scenario I would prefer... but given human history, it's at least a 50% chance that you would get the conflict-ridden model instead.
What I'm wondering is how long it will be until someone like Bigelow sets up their own Golden Rule habitat (from the Heinlein nove). In fact, from what he's announced publicly, I wouldn't be surprised if Bigelow setting up his own Golden Rule is part of the reason he's invested in space habitats like he has.