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#26 2005-01-20 18:50:14

Martin_Tristar
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From: Earth, Region : Australia
Registered: 2004-12-07
Posts: 305

Re: Orion Starship - Orion Starship

Martian Republic,

Yes the current economy in United States isn't going to work for the long term expansion into space. We have to develop alliances through work sharing ( ISS example ) that is not working or economy integration such as EU development with Canada and Mexico to start and call it North American Republic both Canadian Citizens and Mexican Citizens and US Citizens will have a major issue about merging into one country.

Or we innovate and expand our countries assets underwater and into space through innovation using robotics and and new building methods and processes. We need a "think tank" of building , construction, engineering and other development faculties that will expand the understanding into new regions for humans to live and work.

Then the comhined resources could match the growth into space required to expand humanity into the solar system.

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#27 2005-01-20 19:54:14

Martian Republic
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From: Haltom City- Dallas/Fort Worth
Registered: 2004-06-13
Posts: 855

Re: Orion Starship - Orion Starship

Martin_Tristar,

Actually I was thinking more along the line of Nationalizing the Federal Reserve System and calling together a worldwide economic summit to re-organize the world debt and even cancel a major portion of that debt. The present economic system is just about had it. So we should put it out of it misery and put together a new economic system that does work. Once the U.S. Government either take the Federal Reserve System into a Third National or under the Treasury Department, the that changes the whole scope of what the United States can do both down here and in space. Since the United States will have to generate long term credit for both rebuilding American and any space venture that we might choose to get into. I'm talking about generating credit in one to two trillion dollar range, because it going to take something in that order to kick start the U.S. Economy again. At that point we would be picking major project to fund like super train system, subways, power plants, NAWAPA, build a city on Mars in forty to fifty year time. It would take at least two generation to build a city on Mars, because for the first generation we would be developing the technologies and building the infrastructure so that we could build that city on Mars. If we did make it a national mission to build a city on Mars it would take at least generation to put use in a position to be able to build that city on Mars. For the United States to be able to do that, the U.S. Economy would have to double in size and the U.S. Would have to develop all kinds of new technologies to be able to do that. That why the United States should make the commitment to do that. It would permanently put the United States in first place as far as space technologies. Now if the rest of the world want's to come along. Well, OK! Or we could choose to go by our self if our stated mission is too big for the rest of the people on Earth.

Larry,

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#28 2005-01-20 20:27:06

Martin_Tristar
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From: Earth, Region : Australia
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Posts: 305

Re: Orion Starship - Orion Starship

Martian Republic,

I would first look at building a underwater city as a prelude to colonization of space becuase it has similar issues that we could study including human life science factors.

Secondary by-product would be an increase of the borders of United States into the ocean and develop the resources under the sea to expand the wealth of the country through taxation, resource leasing and population growth.

Thirdly, The use of the underwater city as a long duration living and working would be part of their mars training and crew motivation and social dynamics.

I agree that the debit and credit structure need an overhaul but they need to be expanded into a structure that will accommodate space locations and underwater locations with different financial concerns and issues, we might want to separate the land, sea, space activities within the treasury debt structure thus it could manage the value of the securities for the marketplace and can manage risks associated with the activities.

It hard to explain the complexities util we start working through them and managing the ever expanding country's GDP into space and under the sea.

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#29 2005-01-20 21:19:16

Martian Republic
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From: Haltom City- Dallas/Fort Worth
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Posts: 855

Re: Orion Starship - Orion Starship

There probably about 3/4 of the worlds resource that would be at our finger tips if we were to go into the oceans. As to how far we would go into the oceans for colonization I'm not sure of, but we have plenty of land inside the United States that we could develop like Alaska and most of the Western States too, which really has not been developed as such. But, the moon would be a good target to aim for our first effort when it comes to colonization. Assuming that there is frozen water at the South pole on the Moon and we start a twenty to thirty year colonization program to build a base on the Moon for one thousand or more people. We could have one heck of a build up program inside the United States and on the Moon in a twenty year period. The only question is, do will have the will power to do it. Then any Mars Colonization would be ten to twenty behind our Lunar Colonization program.

Larry,

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#30 2005-01-24 11:19:11

SpaceNut
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From: New Hampshire
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Posts: 29,002

Re: Orion Starship - Orion Starship

The Space Review article Revisiting Project Orion

The engineering
Orion will not disappoint. The design achieves an Isp of 12,000 seconds with an Earth-launched payload capacity to LEO of 5500 tons. The fuel would be 800 nuclear bombs.

Not that bombs are lighter there would be an increase to the available payload that one could no deliver with this old style 50's vintage space craft.
The article goes on to mentioning NERVA

Internal combustion nuclear engines have an inherent limit. If the exhaust is too hot, it melts the rocket nozzles. This is an inherent limit in all non-pulsed designs. By using external combustion, fantastic temperatures hotter than the surface of the sun can be achieved, yet the plasma will cool sufficiently as it expands so as not to melt the pusher plate of the Orion.

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#31 2005-01-24 13:10:22

ANTIcarrot.
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From: Herts, UK
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Posts: 170

Re: Orion Starship - Orion Starship

Not to mention that while the orion nukes are travelling through the atmosphere to orbit, they can be stored in very secure and durable containers.

A NERVA though is, well, a nuclear reactor with a hole in the side. That seems a fundimental safety weakness to me. Though I'm sure it could be made 'safe' it could never be made as safe as a fully sealed orion nuke.

Though I would question the sanity of running the engine *inside* the atmosphere. And I worry the numer of anticipated deaths per launch is suspisiously low.

ANTIcarrot.

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#32 2005-01-24 14:04:25

GCNRevenger
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Re: Orion Starship - Orion Starship

The Orion though was originally intended to use its nuclear bombs for ground launch, which would cause a signifigant amount of fallout if nothing else from the massively neutron-irradiated soil around the launch pad, not to mention that radioactive daughter particles from the dozens of warheads themselves.

A NERVA or Timberwind fission engine on the other hand, would capture essentially all the radioactive material in the reactor fuel assemblies. Since solid-core fission engines aren't suited for ground launch anyway because of their low thrust/weight ratios and need for Liquid Hydrogen, the reactors would only be powerd up as an upper stage where their radiation would be inconsequential.

The utility of launching 1000's of metric tons in one go is obviously dubious, it would be a much better idea to invest in RLVs or space elevator research for ground launch and asteroid mining for bulk water.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#33 2005-01-24 14:35:46

reddragon
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Posts: 193

Re: Orion Starship - Orion Starship

Orion would certainly be a big improvement over what we have now for interplanetary travel, but I doubt it will ever actually fly. The legal hurdles and public opposition even to using the bombs only in space would be immense. (Besides there's a treaty banning nuclear weapons in space.) Using fission bombs for launch would never be approved, and rightly so. Even if nothing went wrong the fallout would kill people years later. I think fusion is our best bet for interplanetary travel. It would probably be as much work to get Congress and the public (as well as world opinion) to support Orion as it would be to develop fusion, and fusion would also help solve our energy problems on Earth and thereby generate an immediate profit for its inventor.

I don't know if fusion could ever be safely used for ground launch, though. If we really want to be moving a lot of payload up and down regularly I think we'll need a space elevator.


Far out in the uncharted backwaters of the unfashionable end of the Western Spiral arm of the Galaxy lies a small unregarded yellow sun.

             -The Hitchhiker's Guide to the Galaxy
              by Douglas Adams

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#34 2005-01-24 15:10:50

Cobra Commander
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Re: Orion Starship - Orion Starship

The utility of launching 1000's of metric tons in one go is obviously dubious, it would be a much better idea to invest in RLVs or space elevator research for ground launch and asteroid mining for bulk water.

It depends on what you're trying to do. Launching 5000 tons of communications satellites at a time encased in a giant Orion shell doesn't make much sense, but sending Mars colony ships is an entirely different matter.

Landing all that stuff poses its own problems of course.  ???

For all its faults Orion has two great virtues. It can launch thousands of tons from the ground, and it can be done right now with current technology. Nothing else offers that.

If only we could figure out how to build pure fusion bombs, a "clean" Orion has great potential.  :hm:


Build a man a fire and he's warm for a day. Set a man on fire and he's warm for the rest of his life.

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#35 2005-01-24 16:31:32

GCNRevenger
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Re: Orion Starship - Orion Starship

I don't think we'll have the opportunity to worry about Lunar or Martian colonies until we can figure out how to get things into orbit so easily that we stop bothering to count tonnes and launches.

Orion, as nice as all that power is, doesn't seem all that useful to me for Cislunar or Martian trips due to the expense of its fission bomb "fuel." The complexity of the warheads and the expense of all that Plutonium rules out the use of Orion on a regular basis. Then there are the security concerns and the localized but intense fallout to worry about.

A pure-fusion device is not impossible, and infact is probobly within our grasp with advanced nanotechnological chemical explosives (see "nanoaluminum" explosives). However, they will still be expensive enough and so many will be required per trip that this method will probobly never find favor.

Externally-ignited fusion, using magnets, lasers, charged particle beams, or even antiprotons, will never be light enough for ground launch.

The future will go one of two ways:

1: HLLV rockets will launch componets for large cargo and crew cyclers, which will be fueled, crewed, and loaded by medium (20-25MT) or medium/heavy (~30-40MT) RLVs on both ends of the trip. Possibly with fueling from Earth being supplanted for mined asteroid water.

2: A space elevator and accompanying super space station will be built and reduce the cost to orbit so far construction, fueling, crew, and payloads can be sent up in light-to-medium bites continuously, with elevator cars forming a circut on either side of a ribbon type cable.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#36 2005-01-24 16:48:18

ANTIcarrot.
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From: Herts, UK
Registered: 2004-04-27
Posts: 170

Re: Orion Starship - Orion Starship

True, orrigonally orion was intended to be lauched for the ground, but following apollo it was also suggested to launch the engine into orbit and 'ignite' it there. The 10m version would have required between 6 and 9 100ton-HLLVs. A drop in diameter would of course mean a drop in performance. As Mr Dyson put it, "Nasa astranauths would be flying coach" rather than first class.

Still, there is no reason in theory why a larger pusher plate couldn't be assembled in orbit out of smaller pieces, in the same way large mirrors are made out of smaller ones. Up to a point at any rate.

In any case starting the orion in LEO eliminates many problems caused by starting it in the atmosphere; like flash blindness of observers.

ANTIcarrot.

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#37 2005-01-24 18:15:41

GCNRevenger
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Re: Orion Starship - Orion Starship

Perhaps, but I don't think that the pulse units will ever be simple enough for general purpose tooling around the solar system... special trips, like a manned expedition to Saturn or interstellar probe perhaps, but its just plain easier to use large quantities of liquid hydrogen then it is to build countless nuclear bombs. Especially with an advanced fission power source, like a Vapor-Core reactor hooked up to a VASIMR engine or yes, dare I suggest it, a Gas Core Nuclear Rocket.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#38 2005-01-24 20:07:42

ANTIcarrot.
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From: Herts, UK
Registered: 2004-04-27
Posts: 170

Re: Orion Starship - Orion Starship

or yes, dare I suggest it, a Gas Core Nuclear Rocket.

Oh no! That'll *never* work... tongue

Speaking of orion alternatives though, linear accelerators in theory beat all other systems hands down in terms of ISP (except antimatter) and it's buildable with todays technology. After all, if atom-smashers can accelerate subatomic particles to .9C, then there's no reason something similar couldn't be built in space. More realistically, throwing significant amounts of matter backwards at 10-100kmps is very possible with todays technology. Though such a ship would be delicate, it could use anything as 'fuel' without the expensive/complex requirements of mining hydrogen.

ANTIcarrot.

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#39 2005-01-24 20:26:58

Euler
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From: Corvallis, OR
Registered: 2003-02-06
Posts: 922

Re: Orion Starship - Orion Starship

Speaking of orion alternatives though, linear accelerators in theory beat all other systems hands down in terms of ISP (except antimatter) and it's buildable with todays technology. After all, if atom-smashers can accelerate subatomic particles to .9C, then there's no reason something similar couldn't be built in space.

You still need to get the energy to power the accelerator, and that usually means carrying fissile or fusible fuel with you.  As I have explained before in other threads, that limits you to a maximum possible Isp of about .04C for fission and .08C for fusion.

More realistically, throwing significant amounts of matter backwards at 10-100kmps is very possible with todays technology. Though such a ship would be delicate, it could use anything as 'fuel' without the expensive/complex requirements of mining hydrogen.

That is what an Ion Engine does now.

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#40 2005-01-24 23:29:50

Martin_Tristar
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From: Earth, Region : Australia
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Posts: 305

Re: Orion Starship - Orion Starship

The nuclear fission reactor type engines could be used for rapid transit between earth and moon at a reduced fuel consumption.  I would like also to see a feasibility on the use of fission ractor drive systems in a earth to orbit ( including a one-way booster attachment for leaving in orbit for space development of transfer vehicles for the moon, and long range larger probes for the outer parts of our solar system.

The Orion Engine Systems could be used from earth to mars and beyond. With Hyper velocity around the solar system colonization becomes a cost effective means to expand the space resources.

The first developments are needed within our solar system. With improvements the Mark 1 type drives will be replaced with Mark 2 and so on. But, we would have space stations, colonies and mining stations on asteroids and more.

Again alot of this technology, control mechanisms, software applications, testing and virtual testing process are all needed to be developed and installed before we even get a finish drive system off the ground and into space.

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#41 2005-01-25 06:47:50

ANTIcarrot.
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From: Herts, UK
Registered: 2004-04-27
Posts: 170

Re: Orion Starship - Orion Starship

Isp of about .04C for fission and .08C for fusion.

ISP is measured in seconds, and C is measured in meters per second. If you mean exhaust velocity then that's an ISP of 1.2 and 2.4 million seconds respectively. Which as I said, is about as good as it gets short of using anti-matter.

That is what an Ion Engine does now.

Really? They've built an ion engine that can instaniously switch between using freshly mined ice and rock as reaction mass? ??? Current ion-engine technology requires refined, pure, and rare gasses, which poses problems not present in a mass-driver system if you need to refuel half way through your journey. Ion engines also have corrosion problems not present in frictionless mass drivers.

It's by no means a perfect system, but it does offer advantages that ion engines do not.

ANTIcarrot.

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#42 2005-01-25 06:58:37

GCNRevenger
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From: Earth
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Posts: 6,056

Re: Orion Starship - Orion Starship

The trouble is that to power a linear accelerator up to high "exhaust" velocities, it takes a huge amount of power, which in turn takes a big heavy reactor. This limits the maximum practical speed you can achieve to about 4% of C.

Making a linear accelerator capable of ionizing and flinging light weight water or heavy weight metal ores will make it overal very inefficent compared to optimizing it to do only one. Jack of all trades, master of none, so to speak.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#43 2005-01-25 08:03:16

ANTIcarrot.
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From: Herts, UK
Registered: 2004-04-27
Posts: 170

Re: Orion Starship - Orion Starship

Making a linear accelerator capable of ionizing and flinging light weight water or heavy weight metal ores will make it overal very inefficent compared to optimizing it to do only one. Jack of all trades, master of none, so to speak.

Ah, no sorry - not making myself clear. I'm not talking of a linear accelerator in terms of high-energy-physics, but rather the bucket launcher design proposed for lunar mining. Used as an engine in orbit it could accelerate raw material in buckets and throw it out the back at speeds unatainable in many nuclear types of propulsion. Including, I'm sorry to say, all forms of nuclear-thermal rockets.

GCNRs woudl be perfect if you wanted to fly around and between, say, the moons of saturn, and it's probably the closest we can get to the 'magic rockets' seen in science fiction. But for getting to places like saturn and back again a mass driver would probably be better because of the very high potential ISP and very high 'fuel' tollerances.

ANTIcarrot.

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#44 2005-01-25 11:24:31

Euler
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From: Corvallis, OR
Registered: 2003-02-06
Posts: 922

Re: Orion Starship - Orion Starship

ISP is measured in seconds, and C is measured in meters per second.

Measuring Isp in terms of seconds only makes sense if you believe that force and mass are measured by the same units.  Otherwise it reduced to meters per second.

Ah, no sorry - not making myself clear. I'm not talking of a linear accelerator in terms of high-energy-physics, but rather the bucket launcher design proposed for lunar mining. Used as an engine in orbit it could accelerate raw material in buckets and throw it out the back at speeds unatainable in many nuclear types of propulsion. Including, I'm sorry to say, all forms of nuclear-thermal rockets.

If you want to get a very high Isp with a bucket launcher then you will either need a very big launcher or very small buckets.

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#45 2005-01-25 12:02:53

John Creighton
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From: Nova Scotia, Canada
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Posts: 2,401
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Re: Orion Starship - Orion Starship

The Orion though was originally intended to use its nuclear bombs for ground launch, which would cause a signifigant amount of fallout if nothing else from the massively neutron-irradiated soil around the launch pad, not to mention that radioactive daughter particles from the dozens of warheads themselves.

Maybe this is not such a problem. I enjoyed the quote:

Suppose we simultaneously enact a policy to cut the http://solstice.crest.org/repp_pubs/art … n.htm]coal contribution to global radiation by more than we added radiation to the atmosphere with the Orion launches (for example, by taxing Orion launches and using the money to buy coal emission permits)? Well, we would be saving lives on balance. The absolute moralist nevertheless would say, “No! Just save the lives and forget the Orion launch.”

Given we are launching 1000 tons a pop, can you imagine what could be launched. How many tons would you need to build a rotating space station that can survive outside of earths magnetic protection. How, long could you sustain a crew on that station with 1000 tons of supplies. Sure reusable vehicles are nice and the allow you to ferry crew back and forth but if the station is grand enough you don’t need to ferry crew or supplies as often. Sure Orion comes at a cost but so does everything that is worth while. Given the massive scale possible with such a vehicle I think it is most certainly worth while but it. If politicians which to pressure other avenues that is fine with me. There is more then one way to skin a cat.


Dig into the [url=http://child-civilization.blogspot.com/2006/12/political-grab-bag.html]political grab bag[/url] at [url=http://child-civilization.blogspot.com/]Child Civilization[/url]

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#46 2005-01-25 14:04:04

Earthfirst
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From: Phoenix Arizona
Registered: 2002-09-25
Posts: 343

Re: Orion Starship - Orion Starship

Orion ship makes sense too me, why should America worry about what other countrys think of us. We certianly din't in Irag. One way to get support would be to due a joint mission to mars or the moon to start bases with Russia. The US and Russia have thousand of nukes laying around. I think Russia would go for it like if they provide half the nukes. Since it was Russia and and the US that singed the test band treaty I think they would let Orion happen if they were in on it.
If France protest who cares? A joint project with Russia would get rid of a big international road block. I think the big reason why Nasa din't go with orion was that Sovets would copie are idea and saved their space program. The mer space sation could have been ten times bigger. It would have changed the cold war and and made it hotter with increased in the new space race. Now I think Russia and America could both benfit so that opens the gate. Only problem china and other countrys have nukes too and would copy us. India could send a man to the moon, with orion.


I love plants!

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#47 2005-01-25 14:09:22

John Creighton
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From: Nova Scotia, Canada
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Posts: 2,401
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Re: Orion Starship - Orion Starship

If France protest who cares?

Why should France protest. Didn’t they blow up a whole bunch of islands recently to test some new nuclear weapons? Oh yeah, and not the world didn't end as a result of those tests. Still I am willing to support other technologies instead. Orion is just one technologies that could help us on the road to a space fairing nation.


Dig into the [url=http://child-civilization.blogspot.com/2006/12/political-grab-bag.html]political grab bag[/url] at [url=http://child-civilization.blogspot.com/]Child Civilization[/url]

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#48 2005-01-25 15:08:47

GCNRevenger
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From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Orion Starship - Orion Starship

Given we are launching 1000 tons a pop, can you imagine what could be launched. How many tons would you need to build a rotating space station that can survive outside of earths magnetic protection. How, long could you sustain a crew on that station with 1000 tons of supplies. Sure reusable vehicles are nice and the allow you to ferry crew back and forth but if the station is grand enough you don’t need to ferry crew or supplies as often. Sure Orion comes at a cost but so does everything that is worth while. Given the massive scale possible with such a vehicle I think it is most certainly worth while but it. If politicians which to pressure other avenues that is fine with me. There is more then one way to skin a cat.

No,

Do not be bamboozled by the huge 1,000MT figure, as huge as it is that kind of lifting power will not be useful for the real development of space. Development will never take place until we can build things in space, and it will never take place until we have reuseable medium launch capability... at which point, Orion does not make sense.

In any case, ANY mega-super-heavy launch system (Orion, Sea Dragon, larger NOVA concepts) do not make sense since there is no granularity of capacity: that if you need smaller loads sent more often, you are in trouble. There is also the issue that a structure built on Earth has to handle the G-forces of our strong gravity AND the dynamics of launch in assembled form. A structure in orbit does not need to be able to handle the high G-loadings or vibration from launch, and thus can be much lighter.

Orion might be good for ultrahigh thrust/Isp speciality jobs, like pushing asteroids or manned missions to the outter plants from Earth orbit, but never for day in/day out ground launch. The cost of the warheads themselves will be huge, to say nothing of the vehicle... oh, and you cannot use exsisting intermediate-yeild warheads, they are too powerful, too heavy, and not designed for the purpose.

A word about Anti's railgun drive...

"But for getting to places like saturn and back again a mass driver would probably be better because of the very high potential ISP and very high 'fuel' tollerances."

Nope. The extreme mass of the railgun and its systems will be so large that no practical ship could be built that would get anywhere. To have a high practical Isp for a given system, you would require a very low thrust too.

Bad idea. Just use hydrogen for goodness sakes!


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#49 2005-01-25 15:37:08

John Creighton
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From: Nova Scotia, Canada
Registered: 2001-09-04
Posts: 2,401
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Re: Orion Starship - Orion Starship

Orion might be good for ultrahigh thrust/Isp speciality jobs, like pushing asteroids or manned missions to the outter plants from Earth orbit, but never for day in/day out ground launch. The cost of the warheads themselves will be huge, to say nothing of the vehicle... oh, and you cannot use exsisting intermediate-yeild warheads, they are too powerful, too heavy, and not designed for the purpose.

Vehicles are expensive anyway. The shuttle is a billion dollars a launch. There are about 6 shuttle launches a year, so if the Orion type vehicle can be built that will cost on average 6 billion per launch then it will be well worth it science it will lift nearly 10 times what can be done in 6 shuttle launches. BTW, could an Orion be built that could be reusable with a week or a month turnaround time.

In any case, ANY mega-super-heavy launch system (Orion, Sea Dragon, larger NOVA concepts) do not make sense since there is no granularity of capacity: that if you need smaller loads sent more often, you are in trouble. There is also the issue that a structure built on Earth has to handle the G-forces of our strong gravity AND the dynamics of launch in assembled form. A structure in orbit does not need to be able to handle the high G-loadings or vibration from launch, and thus can be much lighter.

Granularity in capacity is nice but if you have a way to launch stuff much cheaper in a large package then you learn to make the best of it. Plan ahead. Send all your space probes up in one package and despachache them in orbit if necessary. Launch all your satellites up in one package and them ferry them to the right location in solar tugs. If it can significantly lower the launch cost then the lack of granularity can be compensated for by other means. Perhaps the ISS crew will be required to make 6 moth stays in case of emergency perhaps the international space station will be replaced by one with artificial gravity and its own propulsion unit. Orion may or may not be the best step forward, but to me it looks like a step forward. Anyway, lets start pricing the fuell and see if that is one of the significant costs.


Dig into the [url=http://child-civilization.blogspot.com/2006/12/political-grab-bag.html]political grab bag[/url] at [url=http://child-civilization.blogspot.com/]Child Civilization[/url]

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#50 2005-01-25 18:54:13

GCNRevenger
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From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Orion Starship - Orion Starship

Vehicles are expensive anyway. The shuttle is a billion dollars a launch. There are about 6 shuttle launches a year, so if the Orion type vehicle can be built that will cost on average 6 billion per launch then it will be well worth it science it will lift nearly 10 times what can be done in 6 shuttle launches. BTW, could an Orion be built that could be reusable with a week or a month turnaround time.

Granularity in capacity is nice but if you have a way to launch stuff much cheaper in a large package then you learn to make the best of it. Plan ahead. Send all your space probes up in one package and despachache them in orbit if necessary. Launch all your satellites up in one package and them ferry them to the right location in solar tugs. If it can significantly lower the launch cost then the lack of granularity can be compensated for by other means. Perhaps the ISS crew will be required to make 6 moth stays in case of emergency perhaps the international space station will be replaced by one with artificial gravity and its own propulsion unit. Orion may or may not be the best step forward, but to me it looks like a step forward. Anyway, lets start pricing the fuell and see if that is one of the significant costs.

Nonsense, launch granularity most certainly cannot be worked around by "thinking ahead." I don't think you fully appreciate just how excessive using Orion or other "ultraheavy" (~500+MT) superlauncher is. Even one Orion's capacity would exceed the mass of all the space satelites ever launched by man, civilian or military. That is a silly idea, the sheer risk of Orion failing and obliterating a trillion dollar payload alone makes the idea of mega payload launch a senseless one. Orion should only be employed where its unique abilities are worthwhile, like pushing supermassive objects (asteroids, comets) or for outter solar system (beyond Saturn) and interstellar missions.

And there are things that absolutely demand granularity... launching and returning people for instance. Some cargos are also time-sensitive and cannot wait years or even months for launch, such as fueled RTGs for space probes, living things, and so on. Launching cryogenic rocket fuel without a MASSIVE condenser system is also a non-starter, since the fuel would boil off and be gone.

There is also no possible way such a ship could make a monthly or even faster then 6mo schedule. Why? The ground under the thing would be intensely radioactive for months before you could even get near it. Then there is the fun of hoisting the thing off its pusher plate (landing gear would be obliterated, it must decend plate-first), inspect the plate, and load the thing in the middle of nowhere with no infrastructure. It is not a practical reuseable vehicle.

A spaceplane, a two-stage jet-RP1+rocket-H2/O2 100% reuseable medium (20MT or 18 crew) spaceplane, flown fifty times a year can easily access launch costs below the so-called "magic" $500/lbs range, and lower then that when operated by the dozen. Literally daily flights to orbit, operated 100% commertially like a specialty airline, a mere eleven of them could match Orion's maximum likly yearly payload with two flights a year. Make it a one-piece Scramjet vehicle, and the costs could be cut much further.

The future always has been intermediate sized RLVs, and now that technology is ALSO within our grasp too.

I know you will next jump and say "but this doesn't have to be an either/or proposition!," but it is, every penny spent on Orion could have gone some place else, developing a Scramjet spaceplane or a space shipyard or an asteroid mine or a Lunar base or whatnot. This is an essentially zero-sum game.

There is also the problem that the practical mass of Plutonium available to make Orion pulse units out of will never be big enough to make it practical for anything besides special flights, even with diverted Plutonium production from commertial fission power reactors. The units themselves will also have to be developed brand new, as no current warhead meets its needs.

It is just a bad investment for development, plain and simple.

Edit: More thoughts,

-Space probes do need to follow a particular launch window or else require a propulsion stage of rediculous size that would eliminate Orion's lift advantage.

-It is not possible to make a miniaturized Orion and still be practical for ground launch due to the minimum yeild and mass of nuclear warheads and the efficency drops with pusher plate size faster then mass.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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